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An assessment of the knowledge, attitudes, and behavior regarding pesticide application of Thai orchid nursery workers
Kamlang-ek, Venika, Ph.D.
University of Hawaii, 1990
U·M·I 300 N. Zeeb Rd AnnArbor, MI 48106
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AN ASSESSMENT OF THE KNOWLEDGE, ATTITUDES, AND BEHAVIOR REGARDING PESTICIDE APPLICATION OF THAI ORCHID NURSERY WORKERS
A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAII IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PUBLIC HEALTH AUGUST 1990
Venika Kam1ang-ek
Dissertation Committee: D. William Wood, Chairperson Jerrold M. Michael Arthur M. Kodama Walter K. Patrick Richard A. Dubanoski iii
e Copyright 1990 by Venika Kam1ang-ek iv
ACKNOWLEDGMENTS
The completion of this dissertationwould not have been possible without the guidance and encouragement of a great number of people. Although it is not possible to list all the individuals here at this time, I would like to express my deepest gratitude to the Thai Military for continuing financial support both for my academic training and for this research project. I also gratefully acknowledge the special assistance of all the members of my doctoral studies committee for their kind guidance and support which made this dissertation possible. Special appreciation is extended to Associate Professor D. William Wood, my chairperson, for his most valued comments on my research proposal, for kindly providing me with relevant literature necessary to my research, and for giving invaluable advice regarding the interpretation of the data in this research project. I would like to express my most sincere gratitude to Dean Jerrold M. Michael, Associate Professor Arthur M. Kodama, Associate Professor Walter K. Patrick and Dean Richard A. Dubanoski for their helpful guidance and assistance in editing the final draft of this dissertation. At the Mahidol University School of Public Health in Bangkok, I would like to express my sincere appreciation to Dean Debhanom Muangman, Associate Professor Chompusakdi Pulket, Associate Professor Thonglaw Dejthai and Mrs. Sumalee Singhaniyom for their most valuable comments on my research proposal and for kindly providing me with their v individual points of view on my research study. I wish to thank my tutor, Mr. William T. Carlon III, for his continuous assistance in the editing of this paper. Sincere appreciation is also offered to the Shell Oil Company and the Extension Agricultural Officers in Phasi Charoen, Ta1ing Chan, Nong Khaem in Bangkok and Krathum Baen, Ban Phaeo in Samut Sakhon province and Sam Ph ran in Nakhon Pathom province and all the orchid workers in this study for their cooperation throughout the process of data collection. Finally, immeasurable indebtedness is expressed to my father for his unfailing encourpgement during my studies and his outstanding support. I wish to express my deepest gratitude to my mother who passed away with cancer in 1983. I always kept in mind that I should try to help anyone who was touched by cancer. That is how I first became interested in pesticide research and why I have tried to help the agricultural workers who are at risk of this disease. In closing, it is my fond hope that this research will be beneficial to the Thai workers using pesticide in Thailand. vi
ABSTRACT
This investigation examines the knowledge, attitudes, practices and behavioral observation in the use of protective equipment among pesticide users at orchid nurseries in Thailand. An experimental group of 270 people and a control group of 250 were selected by random assignment from two separate orchid-growing areas near Bangkok. An experimental survey questionnaire, field observation and blood cholinesterase testing for toxic effects were the methods used to collect data. Data collection included: baseline data on pesticide exposure, obtained by the Tintometric and the Cholinesterase B test to search for blood cholinesterase activity; the performance of an intervention trial, wherein the experimental group was given health and safety training regarding pesticide use while the control group was given training in pest control; and field observation of all participants as well as a post-test of knowledge retention using the original questionnaire in order to evaluate the learning of contents of the health and safety training. Final blood testing of cholinesterase activity was done in order to determine the differences in results between those workers who had used protective equipment and those who had not. Through demonstrations and pictures, the experimental group was given training in the correct ways to apply pesticides and how to use protective equipment. The control group training consisted only of vii various methods of pest control. Overall, the health and safety training intervention was moderately successful in raising the knowledge and correct practice levels regarding the use of protective equipment in the experimental group. In the final observation of their behavior when spraying pesticide, the control group also showed improvement in the use of protective equipment. This indicates that most nursery workers are aware of the need to wear various articles of protective apparel but are reluctant to do so because of discomfort caused mostly by hot and humid weather. The blood testing proved that both the Tintometric and Cholin esterase Bmethods are effective in checking cholinesterase activity in a field situation. However, toxic effects from pesticides accumulate slowly and major changes in blood chemistry are difficult to detect in the short term. v;;;
TABLE OF CONTENTS
ACKNOWLEDGMENTS ...... iv ABSTRACT ••• ...... vi LIST OF TABLES ...... x LIST OF ILLUSTRATIONS ...... x;; CHAPTER I INTRODUCTION • 1 Development of Pesticide Use • 1 Pesticides and the Environment. 3 Pesticide Use in Thailand 5 Statement of Prob1em ••••••• 10 Pesticide Problems in Other Countries 17 Research Questions • • • • ••••. 19 Hypotheses •••••••••••.• 20 CHAPTER II REVIEW OF THE LITERATURE • 22 Literature on the Problem 22 Unsafe Use ••••• 22 Occupational Exposure ••••••. 24 Hazards to People • • • • • • • • • . • 28 Prevention of Hazards •••••..•• 29 Literature on Methodology of Cholinesterase Activity . 30 Literature on Application of Research ...• 35 Cultural Problems and the Transfer of Pesticide Technology •••.•..•.. 35 Health Behaviors and Pesticide Awareness •• 37 Implication for the Thai Farmers 42
CHAPTER III RESEARCH METHODOLOGY •••••• 45
Research Des ign • • • • • • . • • • . . . 45 Field Survey Administration 46 Sample and Sampling Techniques. 51 Deve1opment of Scales ••••••••.• 52 Data Collection •••••••••. 55 Biological Monitoring of Agricultural Workers Exposed to Pesticides; Cholinesterase Activity in Other Countries • . • • .• .••• 60 Cholinesterase Activity •..•.. 62 ix Health and Safety Program in the Experimental Group •••••• 63 Pest Controlling Program in the Control Group ••••• 63 CHAPTER IV RESEARCH FINDINGS •••••••• 65 Study Focus •••••••••••••• 65 Description of the Management of Data •. 67 Missing Case Analysis (Lost Cases Analysis) ••••••••• 67 Coding of the Data ••••• 72 Description of Study Population ••••• 72 CHAPTER V ANALYSIS II ••••••.•.•• 114 Discriminant Function Analyses 129 Discriminant Function Variables • 130 CHAPTER VI DISCUSSION AND CONCLUSION •••• 148 Interpretation of Chapters IV and V• 148 Results of Hypotheses Testing •• 152 Limitations of the Study •••• 157 Suggestions for Further Research 160 Conclusion ••••••••••• 162 APPENDICES .• ...... 170 A. Interview Schedule 170 B. Results of Preliminary Interview Questionnaires for Persons Engaged in Agriculture •.•••• 178 C. The Tintometric Test and the Cholinesterase B Test ...... 181 D. Operational Definitions • 191 E. Location and Mapping 193 F. Health and Safety Program and Pest Control Program. • 199 G. Translation of the "Booklet of Health and Safety in Using Pesttcide" •••• 205 REFERENCES .••••••.••••••••••••• 215 x
LIST OF TABLES
Table Page 1.1 Formulated Agro-pesticides, the Approximate Amount of Pesticides Imported into Thailand from 1976-1981 ..•• . .•••.•••••• 7 1.2 Types, Quantities and Value of Pesticides Imported ; n 1986 ••••••••••••••.•• 9 1.3 Pesticide Product Imports (January-September) • 9 1.4 National Statistics of Illness and Death from Toxic Substances in Thailand During 1979-1984 15 1.5 Age Groups of Pesticide Poisoning Cases Admitted to the Hospital ••••••••••••••.•••• 16 2.1 Number of Cases of Occupational Disease Attributed to Pesticides and Agricultural Chemicals in California, 1957 • • . • • • • • • • .....••. 26 2.2 Time of Onset of Symptoms 34 4.1 How the Population in the Experimental Group was Divided .•••••••. •• 69 4.2 How the population in the Control Group was Divided •••••••••••••. 70 4.3 Comparison of Age Characteristics of the Experimental Group and the Control Group for all Cases •.•••.•••••...•... 73 4.4 Comparison of Sex Characteristics of the Experimental Group and the Control Group for all Cases ••••• 74 4.5 Comparison of Marital Status Characteristics of the Experimental Group and the Control Group for all Cases •••.•••••••••••••••••.• 75 4.6 Comparison of Education Characteristics Between the Experimental Group and the Control Group for all Cases •••••••••••••••••••••.• 76 4.7 Comparison of Working History Characteristics of the Experimental Group and the Control Group for all Cases ••••••••••••••••••••••••• 78 xi Table Page 4.8 Comparison of Duration of Spraying Characteristics of the Experimental Group and the Control Group for all Cases ••••••••••••••••..••••.•• 79 4.9 Knowledge levels of the Appropriate Use of Protective Clothing for all Subjects before Training. •••• •• 80 4.10 Attitudes Towards the Appropriate Use of Protective Clothing for All Subjects Before Training. • • • • 85 4.11 Practice levels of the Appropriate Use of Protective Clothing for All Subjects Before Training. .•.. .• 88 4.12 Correct Practices Observed at Pre-Test (Before Training) .••••••••••••••••.• 92 4.13 Data on Pesticide Exposure Obtained from Health Examinations of Orchid Workers After Spraying Pesticide ...... 104 5.1 Percentage Breakdowns of Discriminant Function for Using a Mask (Post-test) ••••••••• 132 5.2 Percentage Breakdowns of Discriminant Function for Using Gloves on Spraying (Post-test) 135 5.3 Percentage Breakdowns of Discriminant Function for Using a long-Sleeved Shirt (Post-test) 137 5.4 Percentage Breakdowns of Discriminant Function for Usi ng a Rai ncoat (Post-test) .•••.•• 139 5.5 Percentage Breakdowns of Discriminant Function for Usi ng Boots (Post-test) •••.•••..• 141 5.6 Percentage Breakdowns of Discriminant Function for Usi ng long Pants (Post-test) ••••••• 143 5.7 Percentage Breakdowns of Discriminant Function for Cholinesterase (Post-test) and Using Gloves on Spraying, long Pants, a Mask in Post-test ••••• 145 5.8 Predictors of Actual Use of Protective Equipment in Knowledge, Attitudes, Practices and Observation and the Cho1i nesterase Level. •••.•••••• 146 xii
LIST OF ILLUSTRATIONS
Figure Page 4.1 Mileage Distance Chart in Both Experimental and Control Groups ••• ••••• 66 4.2 Flow Chart of Cases in Study. 71 4.3 Percentages of Correct Responses in Knowledge Pre-, Mid-, and Post-Tests for All Subjects •••••• 82 4.4 Comparison of Owners' and Workers' Percentages of Correct Responses in Knowledge Pre-, Mid- and Post-Tests ..••.•...••....••. 83 4.5 Percentages of Correct Responses in Attitudes Pre-, Mid- and Post-Tests for All Subjects •• 86 4.6 Comparison of Owners' and Workers' Percentages of Correct Responses in Attitudes Pre-, Mid- and Post-Tests • • • • • ••••••••••• 87 4.7 Percentages of Correct Responses in Practices Pre-, Mid- and Post-Tests for All Subjects •• 89 4.8 Comparison of Owners' and Workers' Percentages of Correct Responses in Practices Pre-, Mid and Post-Tests • • • • • • • • • • • • • 90 4.9 Percentages of Correct Practices for All Subjects Observed at Pre- and Post-Tests 93 4.10 Comparison of Owners' and Workers' Percentages of Correct Practices Observed at Pre- and Post-Tests •••..••.•••..•.••. 94 4.11 Comparison of Data in Pre-Tests and Post-Tests for Knowledge, Attitudes, Practices and Observation for Both Groups ••••••••• . ••••••••• 96 4.12 Comparison of Data in Pre-Tests and Post-Tests for Knowledge and Attitudes in Owners' and Workers' Groups .•.•••••.••..••.•••••.•. 98 4.13 Comparison of Data in Pre-Tests and Post-Tests for Practices and Observation Owners' and Workers' Groups ..••••••..•••....••• 99 xiii Figure Page 4.14 Comparison of Cholinesterase Results for Pre-Test and Post-Test • • • ••••••••••••.•• 100 4.15 Comparison of Cholinesterase Results for Pre-Test and Post-Before Spraying, Post-After Spraying Testing 101 4.16 Comparison of Cholinesterase Resu1ts'for Factory and Pre-Test and Post-Before Spraying, Post-After
Spray; ng . • . • • . . . . . $ ••••••••• 102 4.17 Protective Equipment Knowledge Average of Summed Scores for Owners and Workers ••••••••• 106 4.18 Protective Equipment Attitudes Average of Summed Scores for Owners and Workers ••••••• •• 107 4.19 Protective Equipment Practices Average of Summed Scores for Owners and Workers •••••••• •• 109 4.20 Protective Equipment Use by Observation Average of Summed Scores for Owners and Workers ••••••• 111 4.21 Comparison of Experimental and Control Groups of the Scores in Knowledge, Attitudes, Practices and Observation in the Pre-Test, Mid-Test, and Post- Test ...... 112 5. 1 Chi-Square Analyses Results for Socia-Demographic Variables •..•••.•..•.•.•.•.••.. 116 5.2 Chi-Square Analyses Results for Knowledge Variables for Pre-, Mid-, and Post-tests •••••••••• 117 5.3 Chi-Square Analyses Results for Owners and Workers of Positive Responses for Individual Items on Knowledge Pre- and Post-tests by Overall Positive Responses on All Tests ••••••.••••••• 118 5.4 Chi-Square Analyses Results for Attitudes Variables for Pre-, Mid-, and Post-tests •••••••••• 120 5.5 Chi-Square Analyses Results for Owners and Workers of Positive Responses for Individual Items on Attitudes Pre- and Post-tests by Overall Positive Responses on All Tests ••••.•..•••••• 121 5.6 Chi-Square Analyses Results for Practices Variables for Pre-, Mid-, and Post-tests •••••••••••• 123 xiv Figure Page 5.7 Chi-Square Analyses Results for Owners and Workers of Positive Responses for Individual Items on Practices Pre- and Post-tests by Overall Positive Responses on All Tests ••••••••••••.• 124 5.8 Chi-Square Analyses Results for Owners and Workers of Positive Responses for Individual 'Items on Behavioral Observation Pre- and Post-tests by Overall Positive Responses on All Tests ••••. 125 5.9 Chi-Square Analyses Results for Owners and Workers of Positive Responses for Individual Items on Behavioral Observation Pre- and Post-tests by Overall Positive Responses on All Tests •••• 127 5.10 Chi-Square Analyses Results for Knowledge, Attitudes, Practices and Behavioral Observation Variables for Pre-test and Post-tests •••••• 128 5.11 Canonical Discriminant Function 1 in Using a Mask in Post-test •.••.••.•• •••..•..• 131 5.12 Canonical Discriminant Function 1 in Using Gloves on Spraying in Post-test ••••• ·. . . .. 134 5.13 Canonical Discriminant Function 1 in Using Long-sleeved Shirts in Post-test ••••• · .. . .. 136 5.14 Canonical Discriminant Function 1 in Using a Raincoat in Post-test ••••••..• ·...... 138 5.15 Canonical Discriminant Function 1 in Using Boots in Post-test ••••.••••.•• ·.. ... 140 5.16 Canonical Discriminant Function 1 in Using Long Pants in Post-test ••••••••• ·. . . 142 5.17 Canonical Discriminant Function 1 in Using Gloves, Long Pants, a Mask from Cholinesterase Level in Post-test ••••••••••.•• 144 6.1 Observed Improvements in the Use of Specific Protecti ve Equi pment •••••••• .. .. . 155 Map 1 Provinces of Thailand ...... 197 2 Strategic Area for BMR Development 198 CHAPTER I INTRODUCTION AND STATEMENT OF PROBLEM
Pesticides are designed to kill. Agricultural workers whose occupations bring them in close and constant contact with pesticides die, often of pesticide poisoning, often of long-term, debilitating diseases. This study, in part, examines and offers methods of mediating this observed relationship.
Development of Pesticide Use
A pesticide can be defined as a chemical agent that can be used to cause the death of, or the regulation of, organisms that man con siders detrimental to his existence. The intended target species of pesticides are then the insects, plants, fungi, rodents, mites and any other organisms that negatively affect man, causing, for example, reduced crop yields, disease infestation, general nuisance situations (mosquitoes) or real estate destruction (termites, nematodes). By far, the most researched pesticides are the insecticides. In fact, it has been noted that only recently has entomology returned from the near total devotion to insecticide pursuits to the more traditional areas of endeavor. The first insecticides (1860s) were arsenic compounds which are stomach poisons that eventually cause muscle paralysis and death to organisms that eat them. Around World War II (1939), the most widely recognized insecticide ever developed was placed on the market. That organic chemical is DDT, a long-term, 2 highly effective,, broad-spectrum insecticide that causes repetitive nerve discharges and eventually kills the insect (Firestone, 1983). The development of synthetic organic pesticides passed through an accelerated phase during the decades following World War II. The discovery of the insecticidal activity of DDT, lindane and the organo~ phosphates was followed rapidly by the introduction of carbamates. Increases in production were followed by the recognition that such increased use of synthetic chemicals would be accompanied by extensive human and environmental impact (Po1ishuk et a1., 1977). Chemical pesticides hold a unique position among the environmental contaminants since distribution in the environment is the way they are used. Pesticide use in the U.S. was regulated by federal and state govern ments, but continued evolution of the regulatory position has been necessitated by increasing usage and changes in patterns of use. However, in many cases there has been inadequate information on which to base definitive regulatory action. Data have accumulated slowly, but during the 1950s and 1960s there was a major effort to develop sensitive and selective techniques of analysis and bioassay. During the 1970s much greater attention was focused on the implications of pesticide use for human health (Plimmer, 1981). Manis desire to stay healthy and avoid the discomfort caused by pests and to fight their competition for food led to the extensive use of pesticidal chemicals. Unfortunately, pesticides .do not only affect the target pests, but rather do harm to nontarget organisms such as man, wildlife animals, livestock, and aquatic life. Some pesticide residues find their way via the food chain and water supply 3 to man, where they end up in man's body and to some degree deposited in fatty tissue for a long time. Nevertheless, pesticides constitute an important group of chemicals contaminating the environment.
Pesticides and the Environment
Pesticides are introduced into the environment in two major ways: intentional application for pest control as opposed to unintentional or accidental spillage and dumping. Pesticides are introduced into the environment intentionally by direct application in agriculture to fight losses caused by pests, and to water resources to control vector-borne diseases and protect the public health. These direct application activities have their benefits as well as risks. Agricul tural applications of pesticides (i.e., crops, soil, landscape, livestock, and forests) constitute the major direct or intentional route of introducing pesticides into the environment. Pesticides cause a lot of problems when they enter the water and the air. Finally, fish and birds die. Spear (1980) reported that organophosphate pesticide residues have been responsible for periodic outbreaks of acute intoxication among California fieldworkers for over 30 years. In 1971, California established re-entry intervals to protect workers against overexposure to these residues. These intervals are stipulated times which must elapse between pesticide application and entry into the field for work involving substantial foliar or soil contact. The re-entry strategy depends upon a relatively predictable relation between time post application and the level of the pesticide residue. It now appears that there are thiophosphates for which the residue hazard is not 4 related to time in a stable way. This circumstance and the continued occurrence of poisoning incidents have focused attention on the quantititave aspects of the relationships between pesticide residue and toxicological response in humans. In the last decade, considerable progress has been made in elucidating these relationships and it now appears to be possible to outline the data requirements for a compre hensive regulatory solution to this long-standing occupational health problem. In the Hawaiian Islands, the ratio of chlorinated pesticide residues in the Ala Wai Canal water to residues in algae, sediments, and fish was 1:4,000 :9,000 :32,000, respectively (Bevenue et al., 1972). Streams draining agricultural areas have been found to have surges corresponding to the pesticide application times which contributed to the contamination process of Lake Utah with residues of the organochlorine pesticides (Bradshaw et al., 1972). In fish and wildlife, residues of the organochlorine insecticides have been detected at relatively low levels in many parts of the United States. They have been found in pheasants and grouse in South Dakota (Greichus et al., 1968); in oysters, clams, and fish in California (Modin, 1969); in adults and fetuses of fur seals in Alaska (Anas and Wilson, 1970); and in mice, rats, and mongooses in Hawaii (Bevenue et al., 1975). DDT and metabolites residues may have been responsible in egg shell thinning and the decline in the populations of five aquatic bird species on the coast of Texas (King et al., 1978). The organochlorine pesticide residues find their way through the food chain and occupational exposure to the human body where they are 5 stored in the adipose tissue due to their lipophilicity. Residues of DDT and metabolites, gamma-benzenehexachloride, and dieldrin were detected at the part per million levels in human adipose tissue between 1969-1972 in Texas (Burns, 1974).
Pesticide Use in Thailand
Thailand is located in a tropical area where there is plenty of rainfall which is suitable for growing a large variety of crops. The total land area of the Kingdom is approximately 542,400 square kilometers, with an estimated population of 54.96 million in 1988. About 81,000 square kilometers are under cultivation, of which 61,000 square kilometers are devoted to rice farming and 20,000 square kilometers are taken up by such crops as coconuts, rubber, field crops, fruit trees, vegetables and forest trees. It is estimated that 10% of the cultivated area of the country is devoted to upland crops such as corn, sorghum, cassava (tapioca), cotton, sugarcane, jute and kenaf. Thailand also grows many oil-producing crops such as castor beans, soybeans, peanuts, etc. Much of the land is under rotational cropping.
From these diverse agro-ecosystems~ Thailand has numerous pests which can inflict considerable damage on agricultural production. They range
from insects, plant diseases~ and weeds to rodents. It has been estimated that losses due to pests in Thailand account for not less than 115,000 million baht (US $5 billion) per year. Agricultural production in Thailand depends heavily on pesticides to increase yield. Thus, pesticides have become more and more essential to acquire good yields in cultivation. This can be noted from the increasing trend of pesticide importation into Thailand. These pesticides include 6 insecticides, fungicides, herbicides, rodenticides and some other minor pesticides. The early importation of pesticides into Thailand was in the form of finished products. In order to reduce the cost of these pesticides some companies, later on, imported technical grade ingredients and formulated them locally. In this case, the price is competitive in local markets (Boonchob, 1983). According to Staring (1984), the supply and distribution of pesticides in Thailand are mainly the concern of the private sector. Until recently almost 100% of the importation, formulation and manufacturing, and more than 80% of the distribution of agro-pesticides is done by private firms. As of the early 1980s there were 114 importers, 23 packers, 7 formulators and 4 exporters registered; however, many companies combine different activities or undertake various enterprises under more than one registered name. About 80% are sole agents and brokers of overseas pesticide producers, while the rest have facilities to mix, package and market the various products. As a result, 300-350 trademarked pesticides can be found in retail shops throughout the country. Staring also reported that "in the past it was not very feasible to produce materials for pesticides, because of the lack of basic ingredients and technical knowhow. But with the discovery of natural gas and the planned development of the petro-chemical industry, Thailand now has the possibility of producing pesticide materials" (p. 179). Subsequently, some agro-chemical companies have now begun to formulate pesticides locally from imported technical grade materials. Production of pesticides involves only the formulation of materials 7 in liquid or solid form, which are all imported as shown in Table 1.1. The types of pesticides produced will depend on the popularity of brand names. New products may be produced and promoted locally. Low cost and highly effective pesticides will become popular in a short period of time.
Tablel.l Formulated Agro-Pesticides, the Approximate Amount of Pesticides Imported into Thai1and from 1976-1981
Import (in tons) Formulated products 1976 1977 1978 1978 1980 1981
Insecticides 2,530 4,006 5,790 5,236 6,747 6,572 Herbicides 1,277 2,857 5,843 5,700 7,000 9,773 Fungicides 689 1,130 2,814 3,029 2,653 2,624 ------Value ($US million) Formulated products 1976 1977 1978 1979 1980 1981
Insecticides 3.40 5.73 13.17 17.13 24.19 18.86 Herbicides 4.06 3.18 11.41 14.03 14.99 21.01 Fungicides 1.12 2.95 3.88 5.02 5.84 6.04
Source: Agricultural Regulatory Division, Department of Agriculture.
The Thai government has a policy to promote the pesticide industries in Thailand. The National Committee on Fertilizer and Pesticide Industry Development has been set up to develop the industry. Promotional privileges can be granted by the Board of Investment. 8 In 1986, the Ministry of Agriculture and Co-operatives declared 274 pesticides as poisonous articles and registration is required prior to import, manufacture and distribution (Putthipreechapongs and Tayaputch, 1987). Production and trade of pesticides in Thailand is controlled by two Acts. The first one is the Industrial Article Act of 1969, which was amended in 1975. The other one is the Poisonous Article Act of 1967, which was amended in 1973. According to this Act, no poisonous pesticide, listed in the Government Gazette, shall be brought in or imported or taken out of the country or manufactured for trade purposes, or bought by any person unless permission has been obtained from a government official. Each year a large amount of pesticides is imported into Thailand, about 80% of which is in the form of technical grade ingredients. Agro-Chemicals News in Brief reported that the pesticides used in Thailand were imported from 31 countries, mainly the United States, Europe, Japan and others in the form of finished products and technical grade material. Types, quantities and values of pesticides imported into Thailand in 1986 are shown in Table 1.2. Compared to 1985, there was a decrease of 8% in quantity and 2% in value. The decrease is attributable to the lower imports of herbicides, since paraquat is being increasingly manufactured locally. In 1987 and 1988, almost all pesticide products used in Thailand were imported, and high import figures reflected a healthy market situation. From Table 1.3, imports of pesticides and other related products rose by 33.5% to about 63 million $US in the first nine months of 1988 (Jinanon, 1989). 9
Table 1.2 Types, Quantities and Value of Pesticides Imported in 1986
Quantity (tons) (technical grade + Value Pesticides finished product) ($US mi 11 ion)
Insecticide 7,085 31.5 Herbicide 4,081 14.7 Fungicide 3,710 8.3
Source: Agro-Chemica1s News in Brief 10(3), July, 1987.
Table 1.3 Pesticide Product Imports (January-September)
Volume (tons) Value ($US mill i on) Type 1988 1987 +% 1988 1987 +%
Insecticides 5,268.9 5,007.9 +5.2 28.07 20.75 +35.2 Herbicides 6,207.9 4,874.1 +27.0 23.95 18.05 +32.7 Fungicides 4,202.2 3,898.5 +7.8 8.66 6.64 +33.5
Source: Agro-Chemica1s News in Brief, 12(1), January, 1989. 10 Because of the availability of farmland and water resources for agricultural production, agro-chemicals will continue to be in high demand in Thailand. This can be ascertained from the local consumption which is increasing every year. It is expected that during 1981-1985 the demand for pesticides increased by about 60% in value terms. The great increase in pesticide use in Thailand during the past decade has undoubtedly contributed much to increased productivity and higher yields of agricultural products. But unfortunately, increased use of pesticides often results in increased abuse of pesticides as well. At the present time, Thai farmers are being exposed to the dangers of pesticides in greater numbers than ever before. This is particularly evident in the orchid nurseries of Thailand since this sector is currently experiencing a boom and the ever increasing demand for beautiful flowers brings with it all the dangers associated with the widespread use of toxic pesticides.
Statement of Problem
There are more than 25,000 species of orchids found indigenous to the regions stretching from Japan and Korea right down the Indo Malaysian regions to New Guinea and Australia (Pinske, 1986). Orchid enthusiasts in Thailand originally imported a few plants and cultured them for the cut-flower market. It has always been an important policy to continue to preserve and improve the quality of exported flowers. Orchids are now a good business for exporting to many countries in Europe. There are many kinds of orchid nurseries, ranging from the large farms which have a lot of workers to small nurseries in which the family helps to take care of the orchids. In the family-operated 11 nurseries, each person has many jobs to do in tending the orchids. Even young children are taught how to work in the orchid nursery. The pests of orchids include aphids, bugs, mites, thrips, scale insects, snails, etc. They can damage any part of the plant including the flowers. For effective control of the pests it is important to use insecticides and fungicides. Many kinds of insecticides are being used to protect the blooming orchids that are exposed to pests. The workers often mix many kinds of pesticides to spray at the same time and therefore they tend to use quite a lot each time. Pesticide use for the control of plant, human and animal pests is presently common throughout the world. Pesticide benefits relative to their uses in agriculture and in public health are commonly known, since they are well documented, but the pesticide hazards to human
society and the envi~onment are less well understood, and research
- I .... on hazards is less well supported than research on pesticide benefits (Deema, 1983). Data from Siriraj Hospital, which covers mostly the urban Bangkok population, show that during 1980-1984 there was a total of about 1,700 cases of pesticide poisoning, mainly females in the 15-29 age group. About 500 cases were in the 0-12 age group, which is suggestive of the accidental poisoning of young children. In 1985, the Public Health Ministry reported that they received notice of 2,600 cases of pesticide poisoning from the whole country (73 Provinces) and provinces such as Kanchanaburi, Sukhothai, Nakorn Pathom, Samut Sakorn, Chachoengsao, Nakorn Suwan, and Nakorn Rajchasima had more than one hundred cases each. No data were found to evaluate the prevalence of health hazards associated with chronic pesticide exposure. 12 In Thailand, chemical control is mainly used for plant pest control. When there is an incidence of plant pest outbreak, the first thing that farmers will think of is what kind of pesticide should be used. There is little financial support from the administration for research on the hazards of pesticides or research on biological activities of pesticides. Notwithstanding the increase of pesticides applied annually for the control of plant pests, crop losses due to pests have never decreased. There are several reasons for this. One is due to the fact that single crop cultivation is practiced in large areas in Thailand where enough food exists for plant pests to thrive on. Secondly, the pesticides used are not always the most suitable for controlling pests. Thirdly, farmers do not practice good field sanitation after harvesting so that food residues are left in the field for plant pests to survive on until the next growing season. It' has been accepted that the application of agricultural pesticides for plant and animal pest control will not indefinitely reduce losses due to pests. Further, it is also understood that many other problems are associated with pesticides; e.g., pesticide residues in the environment, pesticide residues in food, human and animal hazards associated with pesticides, plant pest resistance to pesticides and outbreaks of infestation by other plant, human and animal pests. Though costs to the public health and the protecting of the environment are high for society, the socioeconomic benefits of pesticides are presently seen to be more important to the society. 13 The benefits of pesticide use have to be carefully evaluated against the cost for each particular pest complex and environmental situation. For most farmers, pesticides are used for only one purpose, and that is to control plant pests as quickly as possible. They have no time to consider whether the pesticides they are now using are or will be hazardous to their health (in most cases farmers spray or dust their own pesticides) or are polluting the environment which results in unsuitable conditions for man's life system. Most farmers do not have enough knowledge about pesticides and have no opportunity to select suitable pesticides according to governmental recommendations. This lack of knowledge increases the possibility of pesticide residues being left in or on food. The fact that 49% of heads of households in Thailand had only a primary school education presents a problem in providing education concerning toxic substances (Report of the Occupational Health Department in Mahidol University, 1984). One of the main problems concerning pesticide use in orchid nurseries is that orchids are generally grown near the house of the owner thereby exposing his entire family to the toxic effects of pesticide drift. It is therefore important for these farmers to take additional safety measures in the spraying, mixing, loading and storing of toxic chemicals. Without such precautions, innocent people could become the victims of pesticide abuse. Thailand is in the tropics, where both temperature and humidity are quite high. Because of hot weather and high humidity, it is inconvenient for the farmers to wear total protective clothing while applying pesticides. Knowledge regarding pesticide toxicity is also 14 not believed to be widespread among the farmers. It is difficult to obtain accurate information on the incidence of poisonings due to pesticides. However, it is a reasonabie assumption that every year a large number of people in Thailand, especially those working in agriculture and horticulture, are poisoned by the pesticides they use. Poisoning may result from careless handling of pesticides by the people engaged in their application. Pesticide poisoning may even result from continuous contact, by absorption through the skin, or by the inhalation of the toxic vapor by the workers in the course of the normal handling of the material, or by swallowing it accidentally. The exact mechanism by which pesticides affect human beings and other mammals is not known in all cases. However, some of the signs and symptoms of pesticide poisoning are known. The user of pesticides should become familiar with these signs and symptoms. Early recognition of poisoning, prompt removal of the source of exposure, and treatment may save a life. Some symptoms are often more obvious to others than to the victim himself. Any abnormal action may indicate the onset of poisoning. Howard (1980) noted that The major symptoms ••• for pesticide poisoning [are] pupil constriction, muscular cramps, muscular weakness and the more general symptoms of vomiting, dizziness, nausea, headache, abdominal pain, chest tightness, blurred vision, difficulty in breathing and heavy perspiration. The common symptoms of pesticide poisoning are headache, nausea, tremors, convulsions, difficulty in respiration, paralysis or coma, etc. The local effects on skin, nails and eyes underline the necessity for the careful handling of pesticides, particularly in concentrated form, together with the need for attention to personal hygiene. Such advice would be given for any irritant or caustic material. (p. 220) 15 Table 1.4 National Statistics of Illness and Death from Toxic Substances in Thailand During 1979-1984
Survey No. of No. of Year Illnesses Deaths
1979 1,835 18 1980 1,851 15 1981 2,170 17 1982 2,187 10 1983 2,353 17 1984 2,795 11
Data from Statistics of Epidemiology Department, Thai Ministry of Health
A research report done by Wongphanich et ale (1985) entitled "Pesticide Poi soning Among Agricultural Workers in Rayong Province, 1984-1985" examined hospital records related to cases of pesticide poisoning. From a total of 15 hospitals, they recorded 1 to 5 cases of pesticide poisoning per month with 66% of them indicating serious health problems. The report goes on to say that the largest number of poisonings were from bipyridyle, followed by organophosphates and carbamates. The age groups of the pesticide poisoning cases admitted to the hospital are given in Table 1.5. Rauyajon (1984) reported that: Careless use of insecticides can indeed harm the users. According to a survey of 426 families in Rachaburi concerning poisonous materials, it was found that more than half of the families in agriculture experienced some kind of illness after using insecticide 16 to spray their plants. Because nearly one-third (29.4%) of the population studied were farmers, this study was able to investigate knowledge about the dangers of insecticide among a sample population. The most common problems mentioned by these respondents included fainting (80.6%), nausea and vomiting (53.7%), skin rashes (24.6%), blurring of vision (21.2%) and diarrhea (14.9%). (pp. 48-51)
Table 1. 5 Age Groups of Pesticide Poisoning Cases Admitted to the Hospital
Age (yrs.) %of Patients under 20 31.8 20 - 29 38.6 30 - 39 11.4 40 - 49 6.8 50 and over 11.4 Data from Wongphanich et al., "Pesticide Poisoning Among Agricultural Workers in Rayong Province, 1984-1985" (1985)
Agricultural workers can be divided into two groups according to the degrees of risk from pesticide poisoning: those who mix, load, and apply pesticides, and those who work in the fields after the pesticide has been applied. The group at highest risk (mixers, loaders, and applicators) must be protected by regulations specifying medical supervision, protective clothing, and closed-transfer systems for mixing and loading pesticides. Field workers are at risk when exposed to unremovable residues of pesticides on foilage. These workers should be protected by reentry times which allow pesticide residues to degrade to safe levels (Peoples, 1981). 17 Pesticide Problems in Other Countries
Jeyaratnam et ale (1987) investigated the extent of acute pesticide poisoning in selected agricultural communities in Indonesia, Malaysia, Sri lanka and Thailand, as well as the contributing factors, because it was believed that this type of poisoning was a major problem in developing countries, but not in the industrialized countries despite their extensive use of pesticides. The study confirmed the existence of this problem, which was found to be due to inadequate knowledge of the safe practices in the use of pesticides among users and to the lack of suitable protective clothing for use by agricultural workers in hot and humid climates. Darmansyah (1977) pointed out that: Indonesia had accepted WHO recommendations to use less toxic pesticides only, abandoning pesticide formulations with an oral lD50 50 mg/kg body weight or a dermal lD50 500 mg/kg body weight, until such time as the Agricultural Extension Services were able to conduct safety programs adequate for the handling of highly toxic pesticides. There was a need for pesticide formulations specifically designed for the climatic conditions of Southeast Asia. Pesticide Protection teams, consisting of a medical doctor, a pharmacist, and sanitarian, were set up in 12 Indonesian provinces; and workshops were organized for them, dealing with the agromedical approach to pesticide management. The program had been extended to 27 provinces. (pp. 169-178)
Pesticide management and safety programs have developed very slowly in Southeast Asia in part because of a lack of competent personnel in the rural areas to communicate knowledge of good farming practices directly to the farmers. Further, no single situation within a country can be looked upon as a solitary problem independent of existing conditions in other areas. Most countries in the region have 18 established some sort of government regulation or act on pesticides, but outside of Australia and Japan they are rarely functioning, enforced, or effective. More effort should be paid towards realization of priority problems, instead of attempting to cover all aspects of the problem with a minimum of personnel. Donham and Mutel (1982) reported that agricultural medicine encompasses the anticipation, recognition, diagnosis, treatment, prevention, and community health frame of the agricultural population which encounter daily a variety of occupational and environmental health hazards, such as toxic chemicals and infectious agents. Agricultural workers had excess rates of chronic illness, excess disability from respiratory conditions, and the highest death rate from occupationally related accidents.
The problems~Thai orchid workers are very recognizable when they are observed working in fields nearby their houses. They were clearly more careless because they could walk back and forth between their houses and their work. Unsafe acts occur all the time, such as never washing their hands while they were having lunch, or while they smoked cigarettes. Even though orchid nurseries in Thailand have a large number of workers, this population and its occupational health risks are as yet unstudied. This research examined behavioral risks and health problems of these workers during the eight months of field research in an area surrounding Bangkok, Thailand. In general, pesticides were seen to be used rather carelessly and even indiscriminantly without taking proper safeguards in agricultural practices. Before this study, there 19 had been a lot of research about orchid nurseries in terms of horticul ture. In this research, however, the focus was on the workers· health and safety practices. In fact, this group of workers can serve as an example of agricultural workers who use pesticides with unsafe practices. This field research could improve the probability that orchid farmers will have a safer life. Hopefully, Thailand will develop a list of unsafe pesticide use practices which might be prohibited by law. This would contribute to the safety of farmers· lives, both in short-term and long-term effects. Although there are little data currently available on the incidence of pesticide poisoning, the workers· health was a main concern in the undertaking of this research. Pesticide exposufe has led to a variety of chronic diseases and, without this type of research, people will be at a loss to explain the origin of their physical illnesses. With the increasingly widespread use of pesticides in Thailand, it will be necessary to investigate the harmful consequences as an important step in preventive medicine.
Research Questions
In developing the research questions for this study, the role of several factors was predicted by blood cholinesterase activity in the blood serum of orchid workers in Thailand. The pre-test and post test blood cholinesterase levels of spray workers were determined by using the Cholinesterase B test and the Tintometric method. Specific objectives of the study were to answer the following questions: 20 1. What are the knowledge levels, attitudes and practices of orchid nursery workers with respect to the toxicity and harmful effects of pesticides? 2. Does health and safety training affect the behavior of sprayers in terms of pesticide use? 3. 00 the nursery workers believe they are susceptible to the harmful effects of pesticides? 4. Why do nursery workers not use protective equipment? 5. What is the relationship between cholinesterase levels in the blood and the levels of worker's knowledge, attitudes and practices in the use of pesticides?
Hypotheses
The study's hypotheses are concerned with the relationships between and among variables. It is hypothesized that: 1. The behavior of sprayers who have received health and safety training will be more positively affected than those who did not receive such training. 2. Individuals who have greater levels of knowledge, more positive attitudes, and more appropriate practices in using pesticides will use protective equipment more often than other groups. 3. Individuals who believe they are susceptible to the harmful effects of pesticides are more likely to use protective equipment than individuals who do not believe they are susceptible to such effects. 4. Individuals who use protective equipment have much better results regarding blood cholinesterase level than those who do not use protective equipment. 21 5. Individuals who have higher levels of knowledge and more appropriate attitudes towards using pesticides will have better results of cholinesterase than other groups who are less knowledgeable and have inappropriate attitudes. This chapter has reviewed the significance of the problems of how pesticides are used in Thailand, and how they affect public health through exposure to the dangers of these toxic substances due to the present lack of suitable controls. The final section presented the research questions and objectives. In summary, it is well known that pesticides are poisonous chemicals but, when used properly, their advantages far outweigh the risks. The risks involved in the use of pesticides can be minimized by educating the farmers and distributors in the safe handling and safe application of the pesticide product. The next chapter relates the study to the literature of unsafe acts of pesticide usage, and to the prevention of pesticide hazards. Also discussed in the behavior of the worker in using or not using protective equipment and finally a review of the theoretical background of blood cholinesterase activity. 22
CHAPTER II REVIEW OF THE LITERATURE
This chapter first discusses the literature related to the problems of concern to this study: the unsafe use of pesticides, occupational exposure to pesticides, the hazards of pesticides to people, and the prevention of such hazards. Then, the methodology of analyzing blood cholinesterase as a measure of human exposure to pesticides is discussed. Finally, the larger issues of the incursion of technology into rural societies and human perceptions of health and illness are considered in terms of their influences upon practices of pesticide use.
Literature on the Problem
Unsafe Use
Frequently, a man who uses pesticides a great deal considers himself to be a "self'-t.euqht;" expert. Not too infrequently, it is this sort of expert or skilled individual who becomes careless. When a dangerous process becomes automatic or routine, it also becomes increasingly hazardous. Most patients who suffer from pesticide poisoning are involved in the formulation of the compounds, or in their agricultural application. Accidental exposure has been reported, as a result of eating pesticide-contaminated, unwashed fruit (Ratner, Oren &Vigder, 1983), and of drinking contaminated residential water (Dean et al., 1984). However, pesticide intake through food, water, and air has been neglected, since the amount of intake was thought 23 to be insignificant. Studies on the subtle effects of this chronic exposure to pesticides have only recently begun. Most cases of poisoning are due to misuse; correct use with inadequate protection is probably the second most common cause (Copplestone, 1980). Furthermore, many pesticides accumulate in the body, and a succession of small does of a chemical, or even related chemicals, collect and can be as fatal as one large dose. This is an unseen pesticide hazard, because although the operator may be extremely careful when first using a pesticide, when he experiences no illness effects, he may become progressively more careless (Bindra &Singh, 1977). The majority of Thai orchid farmers do not know much about the dangers of pesticides and do not use them with sufficient caution. Various types of insecticides may be used differently according to the directions and precautions associated with each kind. Regulation of pesticide use combining agricultural information for the farmer with surveillance of his practices in the handling of pesticides is often the best way to minimize occupational poisoning and restrict residues on the crops brought to market. Many pesticide accidents involving children can be attributed to the improper storage of chemicals. Accidental ingestion of pesticides mostly occurs in situations where they are transferred from the original labelled containers into unlabelled containers which are placed in a house near foodstuffs, medicines, etc. 24 Occupational Exposure
Studies of agricultural workers are valuable in assessing the potential association of pesticides with cancer. Since many of these compounds are known to be carcinogenic under laboratory conditions, attention has been focused on these chemicals as a possible causal factor. Herman et a1. (1985) reported that the concentration of sprayed pesticides in a worker's body is affected by the amount of worker1s skin exposed to pesticide residues. The hands, arms, chest, stomach, and thighs received most of the dermal exposure; particularly, the arms and the hands received the major portion of the pesticide residues. It was concluded, based on the low dermal and respiratory toxicity of the pesticide, that the dosages did not pose a threat to the health of the worker. The National Institute for Occupational Safety and Health (1984) noted that the conditions of heat and humidity increase the amount of poisonings when the farmers spray, because "it is difficult to force operations and farmers to wear heavy clothing for their own protection" (pp. 250-255). Durham and Wolf (962), in discussing the effects of high temperature on the toxicity of various insecticides, noted that many physiological factors promote toxicity, such as high rates of skin absorption of parathion. Bonsall and Goose (1986) observed that skin absorption was relatively consistent in all the studies they noted, ranging from 3% in Indonesia to 6.3% in Thailand, and concluded that there is a "significant increase in the abi 1ity of the skin to absorb chemicals in high temperature and humidity conditions" (pp. 45-59). 25 Sobeih (1986) investigated how the open space of open farms makes weather conditions of rain, wind, sunshine, and humidity important factors in cropworkers' exposure to pesticide residues. The efforts of this study were directed toward the measurement of respiratory exposure of workers and applicators to pesticide residues, along with the estimation of foliar residue levels in plastic bubble and glass greenhouses. The pesticides evaluated were carbaryl, benomy1, methomy1, oxamy1 and captan. Venting and sunny weather were factors that contributed to the rapid dissipation of airborne pesticide residues. Surface residue levels were affected by the pesticide formulation and the method of application. One reason for studying orchid nurseries is that they are a fairly new and expanding industry, in which there is extensive use of a wide variety of pesticides. Studies on people subjected to pesticide exposure through their occupations, such as pesticide factory workers and pest control operators, provide a wealth of information about toxicity. General data on occupational diseases caused by pesticides indicate the source of the hazards. For instance, Table 2.1 shows that in California in 1957 the major problem was in the manufacture and use of organophosphorus insecticides, pointing out the necessity of improving handling processes. Such studies do not necessarily provide the means to prevent or control occupational health problems (West, 1969), but they certainly give scientists a clue as to the possible safety levels of individual pesticide formulations. A more recent survey (Whitlock et a1., 1972) has shown that there were 627 poisonings in a 12-month period in southern California. Thus 26
Table 2.1 Number of Cases of Occupational Disease Attributed to Pesticides and Agricultural Chemicals in California, 1957
Farms Service Manufacturing
Organophosphatesa 109 67 23 Chlorinated hydrocarbonsb 27 14 7 Cyanamide 2 2 1 Lead and/or arsenic 3 9 3 Herbicides 19 16 3 Fertilizers 19 4 2
aOne death by demeton poisoning bInc1udes some fumigants such as methyl bromide and carbon tetrachloride Source: Kleinman et a1. (1960) regions of occurrence have not changed, and there appears to be very little change in occupational hazards. In Japan, there were about 6,000 cases of parathion poisoning in the years 1953-1959 (Namba & Hiraki, 1958). Silverio (1969) estimates that the most commonly seen organophosphate poisoning cases are those of children poisoned by malathion, dich1orvous, and parathion. One type of danger involves contaminants like those present in malathion, a supposedly safe insecticide. Some of the contaminants inhibit carboxyl esterase, the enzyme that makes malathion safe to mammals, and most likely contributed to an epidemic of malathion poisoning among malaria workers in Pakistan (Miller &Mukhtar, 1982). 27 If pesticides are handled carelessly over an extended period of time, long-term health consequences could arise. The problems arising from long-term hazards are very complex and are not well understood. Hoffman (1985) reported that the contamination of the milk supply of the island of Oahu, Hawaii, with the pesticide heptachlor, ••. resulted in the prenatal exposure of infants whose mothers consumed milk and milk products during the period of contamination. Heptachlor is a neuro toxic, lipophilic, organochlorine pesticide which bioaccumulates as it progresses up the food chain. Heptachlor is known to pass the placenta in postnatal exposure of breastfed infants. While heptachlor is a known carcinogen its teratogenic effects were unknown. (p. 3)
A similar problem has occurred in Delhi, India; Zaidi et ale (1989) report how the widespread use of DDT in India has resulted in an increased level of the insecticide in the ecosystem and, therefore, there are possible health hazards. Considering the magnitude of potential exposure, it is all the more startling to find less neuropsychological research on pesticide effects than on almost any other neurotoxic substance in common use. There are probably several reasons why pesticide-exposed individuals and neuropsychologists do not encounter each other more often, reasons that depend upon both individual and sociocultural factors. For what- ever reason, the limited numbers of clinical and research personnel engaged in neuropsychologically related pesticide investigations cannot even begin to address the complexity and magnitude of the problem, the potential dangerousness of these materials, or the frequency of human toxic reactions (Goetz, 1985). 28
Hazards to People
The effect of organophosphorus insecticides on those suffering from acute poisoning is the development of ataxia, and paralysis of limb extremities develops between 8 and 14 days after initial exposure to the toxin (Johnson, 1983). Mild behavioral symptoms can include fatigue, headache, dizziness and abdominal complaints. Extreme weakness or paralysis may result from acute exposure. Carbamates, like organophosphate pesticides, also inactive acetylcholinesterase. Acute symptoms include 1ightheadedness, blurred vision, salivation, weakness and muscle fascicu1ations (Stopford, 1985). According to Gershon and Shaw (1961), many changes in personality have also been reported as a function of exposure to organophosphate and other pesticides. Early case studies describe schizophrenic and depressive reactions to organophosphate poisoning. Patients with manic depressive psychosis, anxiety and depressive neurosis or schizophrenia frequently exhibit degrees of hypercho1inesterase. Minor increases are also associated with electric shock therapy. High serum cholin esterase level has been frequently found in cases where obesity accompanied diabetes. Spastic children exhibit a high serum level of cholinesterase, presumably a reflection of increased activity at the neuromuscular junction (Areeku1, 1981). Emotional effects of organophosphates are consistent with what is known about the cholinesterase-inhibiting properties of pesticides, since percutaneous injections of anticholinesterase in human volunteers produced initial feelings of fatigue, followed by subjective feelings of tenseness inside (Bowers, Goodman &Sim, 1964). 29 Walker (1988) made a study from the self-reports of pesticide victims, noting the "incidence of stress-related symptoms •••• in 817 farm men and women and 109 urban residents. Nearly 50% of the farm sample reported constant occurrence of the symptoms of having trouble relaxing, loss of temper, and .fatigue" (p, 10). Ecobichon and Joy (1982) described a case of carbamate exposure in a 55-year-old farmer who hand-sprayed a vegetable garden with carbaryl. Acute symptoms included severe vertigo, visual impairments, paresthesias, fatigue and memory loss. Photophobia, mild paresthesia and memory loss continued to be experienced one year after exposure, with the patient reportedly needing to continually compensate for memory impairment with written reminders.
Prevention of Hazards
Soerjani (1988) noted that pesticide production and usage in nine Asian countries--India, the Republic of Korea, Indonesia, Malaysia, Pakistan, Thailand, the Philippines, Sri Lanka and Bangladesh--have an impact on public health and the environment.
Problems of pesticide use include: the pesticide treadmill, increasing pesticide application and decreasing efficacy leading to an increase in the complexity of pest problems and unequal sharing of benefits and environmental risks among various community groups; side effects on nontarget organisms, the environment and public health, and poisoning during production, storage, distribution and application; lack of appropriate information; legislation problems, violation of pesticide codes and enforcement problems. (pp, 219-234)
In Thailand, there is a great need to have regulations to control pesticide application as well as a need for farm agents to inspect 30 agricultural fields. These officials must know what protective equipment is available in Thailand and what kind of protective equip ment can be used by and is suitable for Thai farmers. A study in Thailand concerning actions taken after the spraying of insecticides to assure that no residue is left on the body or clothes found that 98.5% of the respondents wash their hands, 97.8% wash their outfits and 80.7% clean up the equipment (Rauyajon, 1984). A Thai researcher reported that 81% of the retail shops stored pesticides separate from foodstuffs. All the pesticides were fully labeled and sealed tightly. Of the shops visited, 85.4% sold nose masks, 63.4% gloves, 49% caps, and 19.5% boots. However, no shops sold aprons or respirators (Wongphanich, 1985). Although protective equipment may be available in many shops in Thailand, it is not used much because it is uncomfortable to wear or it makes the farmers sweat because the weather is so warm. They use short pants when they spray pesticide; they do not wear 10ng sleeved shirts, long pants, or boots because they feel it is very difficult to work with those things on.
Lite~ature on the Methodology of Cholinesterase Activity
Health hazards for man occur mainly from occupational overexposure to carbamate insecticides resulting in poisoning characterized by cholinergic symptoms caused by inhibition of the enzyme AChE. The main routes of exposure are inhalation and skin. From controlled human studies, it is clear that poisoning symptoms can be seen a few minutes after exposure, and can last for a few hours. After recovery starts, within hours the symptoms disappear and the ChE activity in 31 erythrocytes and plasma returns to normal, because the carbamate is rather rapidly metabolized and the metabolites excreted. Nelson and Crawford (1972) summarized the general toxicities of various organophosphates to humans, and concluded that
There are individual susceptibility differences in man that make all estimates of toxicity only approximations in any case. However, there is one great advantage in assessing the effects of organo phosphates on man: their precise mode of action is well known. As far as their acute actions are concerned, these compounds owe their toxicities to their ability to inhibit cholinesterase. Some compounds have their main action on pseudocholinesterase. Some compounds have their main action on pseudocholin esterase while other compounds have a stronger action on acetylcholinesterase. Pseudocholinesterase will hydrolyze acetylcholine only at higher acetylcholine concentrations than exist normally. Slight to moderate inhibition of pseudocholinesterase without inhibition of acetylcholinesterase would not raise tissue acetylcholine levels. Pseudocholinesterase acts to reinforce acetylcholinesterase when tissue acetylcholine levels are elevated. Some compounds apparently irreversibly block cholinesterase while other compounds do not form as strong bonds with the enzyme. (p. 226)
In mode of administration the organophosphate level in the blood apparently rises rapidly before that in the central nervous system goes up. On the other hand~ if the contact is through vapor, mist, application on skin, etc.~ it is possible that the local symptom (not the central effects) can precede the fall in cholinesterase activities in the blood. Although other side effects are known for certain compounds, these are neither abrupt nor fatal. Thus the methods for estimating the degree of poisoning are well enough developed so that chronically or mildly poisoned individuals can be detected before external symptoms begin to appear. Such local effects include irritation of the skin, contraction of the pupil, and asthma-like 32 respiration difficulty. A cause-effect relationship exists between the dose, the severity of symptoms, and the degree of cholinesterase inhibition. Basically there are two groups of organophosphates whose differences in mechanism of action result in qualitatively different effects on blood cho1inesterases. However, the data relating blood cholinesterase levels to specific toxic· symptoms of organophosphate and carbamate poisoning in man are rather limited. The latter require metabolic conversion in the body, so that there is a period before their effect on cholinesterase occurs. With respect to the former,
Lebrun (1960) observed that lI af t er two oral doses of Dipterex the plasma cholinesterase could be reduced to 10% and that of the red cells to 50% of normal value without the appearance of toxic symptoms" (P. 579). In reviewing the significance of blood cholinesterase inhibition, Gage (1967) supports the idea that IItoxic effects are not likely to be encountered if the red cell and plasma activities remain above 50% and 25%, respectively, of their normal values. A threshold limit for blood cho1inesterases is 30% inhibition, above which the worker involved must avoid further contact with the insecticide. This conclusion is based on the fact that blood cholinesterase levels vary to the extent of 15-25% for plasma and 10-15% for red ce11s11 (p. 159). Aside from establishing threshold levels, there are other useful purposes for checking blood cholinesterases. First, recovery from poisoning can be effectively monitored by this method. For instance, studies of recovery from parathion poisoning have concluded that 33 although in general symptomatic recovery is quick, in some cases recovery in cholinesterase levels takes as long as 10 weeks. During such a recovery period, patients are advised to avoid further exposure. Second, cholinesterase inhibition measurements can assist in estab lishing safe doses for various organophosphate and carbamate insecti cides (Leach, 1953). Zavon (1965) reported that "a prolonged low-level exposure to organophosphate insecticide did not usually cause clinical illness until red cell cholinesterase activity decreased to 20 percent or 25 percent of the individual's pre-exposure level ll (p. 51). A 40% decrease in red cell cholinesterase activity from the pre-exposure value is a danger signal and a decrease of 60% is an indication for cessation of working with organophosphate insecticides. Workers identified as cholinesterase-inhibited on routine surveillance should not be returned to work involving potential re-exposure to organophosphates or carbamates until their cholinesterase activity has returned to the previously established base-line. If a base-line is not available, however, decisions regarding return to work are complicated by the fact that patterns of recovery for cholinesterase activity are not well understood. The base-line must be established when the worker has not been exposed to organophosphates for at least 30 days; a minimum of two pre-exposure tests should be performed at least three days, but not more than 14 days, apart. If these two tests differ by as much as 20%, a third sample must be tested. The base-line is obtained by averaging these tests. 34 Jeyaratnam et a1. (1982) reported from a government district hospital in Sri Lanka on 23 persons who had been admitted after using the knapsack type of spraying equipment during the paddy cultivation season of May-July, and noted that symptoms of acute pesticide poisoning occur during spraying operations or at the latest within 4 hours of cessation of spraying. Table 2.2 shows the time relation ship between the onset of symptoms and spraying operations. More than half of the patients developed symptoms either during spraying or within one hour of stopping work. All of the patients were aware of symptoms within 4 hours after cessation of spraying. There was no observed relationship between severity of the patients' condition and time of onset of symptoms (p. 205).
Table 2.2 Time of Onset of Symptoms
Number of Time patients
While spraying - < a half hour after 7 a half hour after - < one hour after 6 one hour after - four hours after 10 Total 23
Ref: Data reported from a government district hospital in Sri Lanka by Jeyaratnam et a1. (1982) 35 Literature on Application of Research
Cultural Problems and the Transfer of Pesticide Technology
The real essence of culture lies in what we think about our attitudes, our social forms, and our religious beliefs; the universal belief in the superiority of one's culture is a powerful force for stability. The attitude of fatalism is closely allied to the forces of tradition and constitutes a barrier equal in strength to these forces (Jones, 1979). In nonindustrial societies, a very low degree of mastery over nature and social conditions has been achieved. Under such circumstances, it is not surprising that people have few illusions about the possibility of improving their lot. Afatalistic outlook is the best adjustment the individual can make to an apparently hopeless situation. Some cultures value novelty and change positively, for their own sake. The fact that something is new and different is sufficient reason to examine it and perhaps to try it. It is clear that in societies where positive structures against being tempted by novelty are strong, where sayings are quoted to validate tradition, and where fear of criticism haunts the would-be innovator, a fertile field for a broad program of social change does not exist until after a good deal of preliminary cultivation has been done (Helman, 1985). Problems of cultural adjustment to innovation lie behind the problems of pesticide use in Thailand. The idea of using pesticides to kill pests came to Thai agricultural workers from the United States and Europe. Thai farmers adapted the idea to their farms and tried to adjust pesticide use to their own ways~ Thai farmers generally 36 do not know the trade-names or ingredients of the pesticides that they use. They learn about the direct action of the pesticides through personal experience and through information from neighbors that helps them in decision-making about pesticides. The farmers tend to use the same trial and error methods with pesticides as with other agricultural methods. Therefores liquid concentrates with acute toxicity are popular. The farmers prefer to see immediate results from the insecticides that they uses selecting fast-acting, highly toxic types (Stone, 1983). Generally, when Thai farmers apply pesticides in their fields, they only think about killing pests and making a profit from their farms. They are not concerned with the hazards of pesticides to their bodies, but rather they become careless after they get used to them, and do things such as walk around their farms with bare feet and without a long-sleeved shirt or long pants. When a dangerous process becomes automatic or routine, it also becomes increasingly hazardous. Jeyaratnam, lun and Phoon (1987) reported that "agricultural laborers were studied in Indonesia, Malaysia, Sri lanka, and Thailand to determine the extent of acute pesticide poisoning •• A program of education and training for the safe use of pesticides for occupa tionally exposed workers was suggested" (pp. 521-527). However, the implementation of such a program is not easy. For example, farmers tend to be receptive to methods that they can see and evaluate directly, and skeptical about information concerning new protective equipment that is communicated through mass media or classroom-type workshops. This may be so because the desire 37 to read and write usually comes late in the development of peasant society. Villagers do not look upon literacy as an abstract thing that is good in itself. It is something that takes time and hard work, and when it is achieved it has no meaning for most of them. If they read and write, they will readily accept new methods they could observe directly and evaluate in the field.
Health Behaviors and Pesticide Awareness
The major reason for distinguishing health and illness behaviors is the suspicion, now reasonably well-documented, that different sets of determinants are needed to understand them. Illness behavior takes place in the presence of symptoms which may sometimes be compelling enough to provide all the motivation the person may need. Health behavior, on the other hand, takes place in the absence of symptoms, and thus the issue is educating people and finding the right cues or triggers for action. For a variety of reasons, an individual may be unable to carry out his or her health behaviors. These reasons may involve the physical, social, and/or psychological state of the person (Kirscht, Becker, &Eveland, 1976). Social disapproval and family criticism, as well as deeply ingrained habits, may interfere with following the regimen (Kirscht &Rosenstock, 1979). In fact, a great variety of obstructing or facilitating factors are likely to influence whether the behaviors are carried out (Aday &Andersen, 1975). Rosenstock (1980) described health and safety actions as influenced by the individual's motivation, his perceived susceptibility to illness, the perceived severity of illness, socially and individually determined 38 beliefs about the efficacy of alternative actions, psychological barriers to action, interpersonal influences, and one or more cues or critical incidents which serve to trigger a response. Health behavior involves a number of social and behavioral issues, including thoughts and feelings, interpersonal relationships, and the influence of social class and culture (Dimatteo &Dinicola, 1982), as well as the health delivery system and its policies. Philosophically, human behavior does not occur in a vacuum but within a social system. The Health Belief Model, in its original form, was developed from the phenomenological theory of the life space, first formulated by the psycno10gist Kurt Lewin (1951). The developers of the Health Belief Model were social psychologists who worked within the public health service. Their basic concern was to determine why people avoided preventive measures (such as immunizations) and health screenings even when these were provided at no cost (Rosenstock, 1974). The Health Belief Model hypothesized that people seek and comply with health care regimens only under specific conditions. They must possess some minimal level of health knowledge and motivation toward health. They must also believe they are vulnerable to a threatening illness condition and concerned that the treatment can be efficacious, and that the cost of such control is not too high in view of the benefits. The phenomenological orientation on which the Health Belief Model is based asserts that current dynamics within the individual affect health behavior. It is the person's present beliefs and expectations that influence what he or she will do. Of course, the individual also must feel threatened by the disease (having high 39 susceptibility and severity) and must feel that he or she has some power to overcome it. In general, the Health Belief Model derives from a naive cognitive orientation, and usually belief content is not of interest, except as an example of, or vehicle for, the structural and process variables. In contrast, Skinner (1971) believes human behavior should not be attributed to nonphysical affective states. Feelings, attitudes, intentions and ideas simply accompany or follow behavior, and to under stand the cause of behavior one must investigate antecedent external circumstances. In many ways, attitudes and beliefs were overemphasized in social psychology under an assumption that they were closely tied to behavior (Kelman, 1974). In the discovery that attitudes have rarely been demonstrated to predict specific behaviors (Wicker, 1969), reactions ranged from shock to elaborate justification to reconsider ation. Some theorists have turned the whole business on its head, making attitudes a consequence of, or self-induced "explanation" for, behavior (Bem, 1967). Some have developed better elaborated theories of specific belief components that are intended to relate more closely to behavior (Ajzen &Fishbein, 1975) in place of the traditional attitude concept, and some have sought to specify the place of attitudes in relation to other factors concerning behavior. It has been generally recognized that any specific behavior is multiply determined and that situational forces provide powerful constraints on behavioral expression of more general beliefs. 40 Kirscht (1973) mentioned that the socio-psychological approach focuses particularly on patients' beliefs, perceptions, attitudes, and motivations: In terms of preventive health behavior, the Health Belief Model is one of the most influential socio psychological approaches; designed to account for the ways in which healthy people seek to avoid illness• ••• If the individual perceives greater threat from an ill health condition, or if health motivation is increased, or if the perceived value and/or likelihood of an action to reduce a threat is increased, or if the costs of an action that is efficacious against a threat are reduced, or if some combination of these changes takes place, then the likelihood of the action is increased. (pp. 3-12)
People have innumerable beliefs, but they do not act in accordance with, or in recognition of, all their beliefs at a given time. Some notion of variable salience is needed to bring belief systems into play. For the Health Belief Model, it was recognized that activation of the pertinent beliefs was necessary; this function was given to cues, either internal or external, that triggered the latent cognitions. Cues, however, have never been explicitly studied (Rosenstock, 1966). The Theory of Reasoned Action, formulated by social psychologists Martin Fishbein and Icek Ajzen (1975), asserts that human social behavior (including cooperation with medical regimens and preventive measures) is not controlled by unconscious motives; it is not thought less. Rather, the theory holds that people decide to engage or not to engage in a given action by carefully considering its implications. Behavior is under volitional control and is a function of the person's intention to perform or not to perform the particular behavior. Ajzen and Fishbein make a firm distinction in their theory between attitudes 41 and beliefs. Beliefs regarding the value of the goal and one's expectation of attaining it combine to produce an attitude toward the behavior. Kasl and Cobb (1966) refer to preventive health behaviors as those actions taken to prevent the occurrence of disease. In relation to pesticides, preventive behaviors include actions such as wearing protective clothing, gloves, leather and canvas shoes, and eye goggles when spraying pesticides on the crop. Pesticide-related behaviors are activities undertaken by individuals for the purpose of preventing, discovering suitable remedies for, and recovering from pesticide poisoning. In other words, pesticide-related behaviors refer to preventive health behaviors, illness behaviors, and sick-role behaviors. Pesticide-related behavior, therefore, should be critically investigated by using a careful combination of theoretical models. Models of behavior prediction have long been of interest to the behavioral sciences. Overe 30 years of research in the measurement of attitudes has provided methodologies which reliably assess attitudes toward the performance of specific behaviors. The predictive power of these techniques is improved if measures of attitudes and behavior correspond in context, target, action and time elements (Ajzen & Fishbein, 1977). The way a person behaves and the practical consequences of that behavior form part of an observable, physical system. And the system can be controlled by programming positive and negative reinforcements. Serious misconception about health and safety methods for using pesticides on the part of farmers should be encountered through 42 field-level training programs using handouts rather than written or lecture-style teaching methods. And one should consider Robins and K1itzman 's (1988) assertion that successes in "design, implementation, and evaluation of health programs were associated with differences in employee assessment of the usefulness of health and safety training, changes in employee work practices, working conditions, and organizational handling of health and safety problems" (pp , 451-472l. Husman (1988) concludes in his research in Finland that occupa tional health services for farmers seem to be effective by making work behavior safer and establishing adequacy and effectiveness in actual situations at the behavioral level. Further, it should not be forgotten that farmers have financial problems too; they might not have money to buy protective equipment. It is clear that the recipients of public health aid, agricultural extension projects, and community development programs are learning novel techniques, acquiring facility in the handling of new tools, and changing attitudes and customs that impinge on many areas of their lives.
Implication for the Thai Farmers
A commonly-discussed characteristic Thai quality is the desire to be free of supervision and to be independent. Mole (1973) noted that people in Thailand seem to always operate on two distinct levels of consciousness: one is their feelings and desires while the other is their external behavior.
The Thai social structure ••• maintains a rather strict code of behavior in superior-subordinate 43 relationships. For instance, in this code a sub ordinate is never expected to contradict his superior as the latter is credited with being knowledgeable in his position. Moreover, subordinates become rather dependent on the superior in private life as well as on the job•••• Beneath a surface submission there seems to be d striving or longing for independent action and freedom from restriction. (p. 53)
The cycle of life of all status groups in Thai society revolves directly or indirectly about activities associated with Buddhism, since almost every community has its Buddhist temple and its monks. Religion was and still is to a major extent the keystone of Thai culture. Cosmological and astrological beliefs have dictated the concept and form of the governmental structure and of rituals, and affect the timing of most human activities. While this is in total accord with the Buddha1s teaching, the concepts of supernatural power and deities continue to affect human relations, religious and agricultural rituals, and the arts. Regardless of philosophical concepts, most Thais seem to believe in karma and reincarnation: do good, receive good; do evil, receive evil. This concern with merit and karma cannot be ignored in the evaluation of Thai value-behavior patterns. From the point of view of this study, the orchid farmers had the same behavioral pattern, which made them hold mistaken beliefs and attitudes about using pesticides. They did not have an awareness of the need for safe practices in applying pesticides because they believe in the concept of merit and karma. They thought that they did their job as best they could, and whether they got sick from the fumes of the pesticides depended on their karma. 44 How careless they were seemed to be influenced by their background: age, sex, education, or experience in their jobs. They tended to have more of an awareness of applying pesticides carefully if they had a good education or were older. Thai farmers received their knowledge from their community about what was shown by experience to be incorrect or correct for applying pesticides and about using the protective equipment. How they applied pesticides depended on their understanding. As long as they recognized these certain basic concepts of using pesticides, they would have more thoughtful attitudes toward applying them. In conclusion, the discussion of the theoretical literature in this chapter describes the complexity of the situation regarding Thai orchid workers. Although the workers seem to be resistant to changing their unsafe acts in using pesticides, the fact is that if they know about the dangers of pesticides they might increase their sense of awareness and change their behavior. The next chapter describes the research methodology and includes a discussion of the research design, sampling methods, sample size and methods of data collection. 45
CHAPTER III RESEARCH METHODOLOGY
This chapter describes the research methodology used in this study including a discussion of the research design, sampling methods, and sample size. A second section describes methods of data collection, field survey administration, design of the structured interview schedule and pretests for validity and reliability of the question nairs. Finally, a method of detecting cholinesterase levels, including a discussion of the development of scales is presented.
Research Design
This study used a combination of survey and repeated measures data collection methods to observe and interview subjects during two different time intervals. Beginning in February, 1988, all of the research subjects were given a checklist of actual behaviors, and observations of their pesticide handling were conducted. In June, the participants were divided into two relatively homogeneous groups and given a questionnaire about their knowledge, attitudes and practices in terms of pesticide spraying and usage. The questionnaire was administered during an interview conducted by a public health researcher. To allow for the study of the variables in this research, a questionnaire probing the socio-demographic characteristics of the respondents and their attitudes was prepared. The topics covered in the questionnaire included: 46 1. Socio-demographic information; 2. Knowledge of correct pesticide application; 3. Attitudes toward application methods. Actual behavior in using pesticides was observed and recorded. Blood cholinesterase activity was measured by the Cholinesterase B test and the Tintometric method. The research was conducted with an aim toward testing a hypothesis related to the problems of unsafe acts in applying pesticides in Thailand.
Field Survey Administration
Atotal listing of all orchid nurseries was obtained from the extension division of the Agriculture Department, which showed that there were more than 7,000. In November, 1986, 170 orchid nursery workers from areas around Bangkok were screened by questionnaire in an attempt to select a first sample to examine a series of hypotheses related to pesticides and orchid workers. later, a homogeneous group of 400 individuals was selected as the target population for the research project. Those individuals selected were all in reasonably good health and had similar educational and socioeconomic backgrounds. They were later divided into two similar groups on the basis of their residence in two areas separated by more than 24 miles, to prevent inter-grQup contact (the division is discussed in more detail in Chapter IV). In May, 1987, the agricultural extension office in Bangkok was contacted and more information was obtained about the density of orchid farms in Thailand. The highest densities were in Phasi Charoen, Taling Chan and Nong Khaem regions in Bangkok, and Krathum Baen and Banplang 47 districts in Samut Sakorn province and Samphran district in Nakorn Pathom province. In June, 1987, agricultural extension officers from Banplang and Krathum Baen districts in Samut Sakorn province and Samphran district in Nakorn Pathom province attended pest control classes. These individuals were in good general health and were asked about their knowledge of pesticide application. Information obtained from orchid nursery owners showed generally high levels of education and low levels of alcohol consumption and tobacco use. In July, 1987, before using them in the field, the questionnaires were pre-tested on subjects in Loei province (northeastern Thailand) where they were given to Grade 5 Thai students in order to assess the readability of the questions. Following this trial, some questions were revised and others eliminated. In December, 1987, the main office of the agricultural extension branch was contacted and asked for permission to do the research in each area. The planning schedule was given to the branch to allow for the arrangements of times and areas, and for the explanation of how to complete the checklist on each orchid nursery. Twenty officers were provided by the Ministry of Agriculture for doing the checklist. In January, 1988, the revised questionnaire was completed and subjected to a pre-test with 50 Thai orchid farmers who had farms in Chiangmai (northern Thailand); this was not the same group as in June 1987. The method of "back translation" was used to finally prepare this version because the Chiangmai farmers have their own dialect, which is not the same as that of the central part of Thailand (Brislin, 48 Lonner, &Thorndike, 1973). After moving back and forth between languages, a concept might be shown to have been readily expressible in the original version. Fifty individuals, all of whom were nursery owners, were given the pre-test. As a result of this trial, the first part of the questionnaire on lifestyle was not changed, but the parts on knowledge, attitudes, and practices in using pesticides and the checklist of actual behaviors in using pesticides were revised, keeping only the content but changing the way the questions were written and the multiple choice answers. In February, 1988, 12 university graduate students in social sciences who had some working experience in conducting face-to-face interviews were engaged for this study. These interviewers were trained to maximize their consistency in interview delivery. First, they were assigned practice interviews in the field. Second, an intensive course was held emphasizing a working knowledge of using pesticides correctly, the specific objectives of the study, data collection and interviewing techniques. Finally, all of the questions on the interview sheet were reviewed to assure that the interviewers clearly understood the intent and flow of the questions. From the middle of February until the middle of March, 1988, the participants were divided by random assignment into two groups each of 200 participants for the pre-test: Group 1 (the experimental group) and Group 2 (the control group). Interviewers were divided into two groups, A and B, that were assigned to households in the same sub district in each area. After obtaining details regarding each area and mapping where the household samples resided, we learned that almost 49 all of the research areas could be accessed by car, except for the Banplang district, which could be accessed by boat. Both the experi mental and control groups then completed the questionnaire to evaluate their knowledge, attitudes, and practices in using pesticides. After the interviewers finished their task, they distributed two cards, pink cards and blue cards, which were reminders of blood sample appointments and training timetables respectively. When finishing this process, the agricultural officers were not allowed to ask the participants any questions. They used the checklist of actual behaviors when they conducted their observation of pesticide handling by all participants during their subsequent visit with the orchid workers over the following four-week period. Near the end of March, 1988, baseline data on pesticide exposure were obtained by using the Tintometric and the Cholinesterase B test to search for blood cholinesterase activity. One month was spent on pre-test data collection and two weeks on collecting blood samples at centers such as schools nearby the nurseries. We offered trans portation to the centers, but some of the workers could not come for various personal reasons, such as the export company wanted them to cut flowers immediately or there was heavy rain. The people who came for a blood examination did not spray insecticides before having the exam. Regarding the blood samples, the blood cholinesterase activity was measured by both the Cholinesterase B method and the Tintometric method during pre-testing, but the Cholinesterase B method was the only one used in the post-test. This was because the Shell Oil Company offered to participate only in the pre-test. 50 In the middle of April, 1988, Group 1 (the experimental group) was given health and safety training (Appendix F) regarding pesticide use while Group 2 (the control group) was given training in pest control rather than health and safety training (Appendix F). Three weeks after the blood examinations, we conducted a health and safety program for the experimental group and a pest control program for the control group, and, when the training was concluded, each respondent in each group completed the original questionnaire (mid-test). We followed up each respondent and the resu1t.s were compared. In June, 1988, all participants were observed in field settings. In July, 1988, all groups, containing the same respondents as in the pre-test groups two months after training, were scheduled to be given a final field observation and to complete the original questionnaire (post-test) for the last time in order to evaluate the retention of the health and safety training contents. However, many orchid workers and temporary workers and, unfortunately, some of the respondents had quit their jobs and they were dropped from the study. In addition, blood testing of cholinesterase activity was done in order to confirm the differences in results for those workers who had used protective equipment. At that time, blood samples were collected before spraying and at least three hours after spraying. As a final assurance of equal treatment of each group, a health and safety booklet was given to the experimental group after the health and safety training but not to the control group until after all the required data had been collected (copy in Appendix G). Final data collection was done from the first week in August until the first week in September, 1988. 51 Sample and Sampling Techniques
After we distributed personal questionnaires in Thailand in November 1986, information from 170 subjects was obtained. These subjects consisted of 128 males and 42 females, and their ages ranged from 20-60 years. The majority of these participants were in the Nongkhaem region of Bangkok province, and in Samut Sakorn province. Most had attained at least Grade 4 education or higher. Most respondents had been doing this type of work for 6-10 years. In general, insecticides were used either in the morning, evening or both. They sprayed pesticides four times a month or more by themselves and almost all of them were owners of orchid nurseries. They mentioned using insecticides such as Diphos 50, Dithane LF, Lannate, Azodrin, Mitac, M-777, and Orthocide. They tended to mmix many kinds of insecticides at the same time (Appendix B). A sample size of 400 was selected to assure that statistically significant differences could be detected, if they existed. This meant that for mean differences (d), given a power level of 0.8 and a
criterion of P < 0.05, values of (d) greater than 0.25 could be found. For Pearsonian correlations, (r) values greater than 0.15 were detectable (assuming the same values of power and pl. Finally, R-squre values greater than 0.1 with k=3 were detected with these same parameters. in determining individual samples within each household, the names of all owners of each nursery were listed by the main Agricultural Extension Office in Bangkok, and then a random selection was made from among the higher density villages, because some Villages had a small 52 number of orchid farms. In addition to the sample core in each area, we also tried to interview everyone that we had on the list. However, if we could not find a specific person, we would pick another one in the same household.
Development of Scales
Another aspect of data quality, besides response rate, is the accuracy and completeness of responses to questions. A personal inter view makes it easier to build rapport between interviewer and respondent, motivating the respondent to fuller and more accurate answers. Dillman (1978) found that questionnaires up to 12 pages, or 125 individual responses, produced response rates that did not depend on length. Beyond that length, which represents a relatively short questionnaire, increasing length decreased response rate. The structured interview schedules which were prepared cover all the variables in the study objectives as follows: Part 1. Socio-demographic characteristics. Part 1 concerned general lifestyle information based on the Thai social-cultural background. The questionnaire included the following sections (variables a4 to a33): age, sex, marital status, education, orchid nursery position as employer or employee (to determine financial resources for purchasing safety equipment and responsibility for providing pesticide safety training, a key factor in examining the use of protective equipment), the number of years worked at the orchid nursery, alcoholic beverage consumption, smoking habits, and duration of spraying insecticides. 53 After the pretest data collection was completed, the data were entered on a micro computer and analyzed. Part 2. Questionnaire for knowledge of using pesticides. The questionnaire inquired about the knowledge of pesticide use, knowledge of the hazards and dangers in pesticide use, and in using protective equipment, spraying, mixing, loading, and storing (variables a44 to b15). The statements required a response from multiple choice answers and were collected three times: the pre-test was the first time; the mid-test, after completion of training, was the second; and the post-test, two months after training, was the third. Part 3. Attitudes towards the use of pesticides and of protective equipment. Individuals evaluated personal safety in view of the toxicity of pesticides, including perceived harmful effects from using pesticides and perceptions concerning the toxicity and health dangers of using pesticides. Attitude scales used Osgood's technique (Osgood, Seui, &Tannenbaum, 1964). Attitudes questions included the variables b16 to b31. These were collected three times as above. Part 4. Section 1. Practices questions. The questionnaire focused on the practices in using pesticides and in using protective equipment and spraying (variables b42 to b78). The questions required a response from multiple choice answers and were collected three times as above. Part 4. Section 2. Practices in actual behavior using pesticides. Observations of actual behaviors in using pesticides were collected. Field observers used a checklist to record their observations 54 (variables clO to c18). The statements were judged to be correct actions or incorrect actions (by answering yes or no) as determined by observation of behavior by the agricultural officials, who were chosen after a screening interview and carefully trained in the procedures of the checklist. These data were collected twice: the pre-test was the first time, and the post-test, two months after training, was the second. The agricultural officials were not allowed to ask any questions, but only used the checklist of actual behaviors to conduct this observation of pesticide handling during any visits to the orchid participants. Part 5. Blood cholinesterase activity and estimation. The results of the blood samples (variables c20 to c45) included: pre-test sgpt (SERUM-GLUTAMIC-PYRUVIC-TRANSMINASE), pre-test sgot (SERUM-GLUTAMIC-OXALOACETIC-TRANSAMINASE) pre-test cholinesterase, post-test sgpt (before spraying), post-test sgpt (after spraying), post-test sgot (before spraying), post-test sgot (after spraying), post-test cholinesterase (before spraying), post-test cholinesterase (after spraying). Part 6. Health examination of orchid workers. This questionnaire (variables f4 to f7) assessed age, sex, nature of work (mixing, spraying, mixing and spraying), and also asked about the frequency of spraying insecticide, how much area is sprayed on each farm, how many people help each time, and symptoms after spraying. A baseline of blood cholinesterase was established from industrial workers who had never been involved with pesticides. These control group data (variables g4 to g10) represented age, sex and the results 55 of blood cholinesterase testing by the Cholinesterase B test (Wako Pure Chemical Industries).
Data Collection
In order to achieve the objectives of this study, both open-ended in-depth interviews of key informants and structured naturalistic observations of sprayers were conducted. The primary purpose of the initial interviews of key infonmants was to assure that all salient factors potentially affecting personal protection, environmental modification, unsafe acts and unsafe conditions in their work places were assessed in this experimental survey. The criteria for the selection of key informants was the probability that the interviewee could and would have access to intimate data on the person who applied pesticides in this field survey. The questionnaires were used to assess knowledge, attitudes, beliefs, and practices of pesticide use. Only the behavioral observation part was conducted by the agricultural officials in each area. The main purpose of the field observations was to observe the sprayers in terms of their acceptance or rejection of the usual protective equipment, their continuance of careless behaviors such as storing pesticide containers in the wrong place after they finished using the pesticides, their awareness of the toxicity of pesticides, and their families, neighborhood and animals. Bulmer (1983) mentioned that in developing countries it is particularly important to avoid trivial or unnecessary inquiries, not only for the sake of efficiency of time, but also because of the expense involved. Therefore, only the essential characteristics of the population were selected. The 56 economic characteristics were eliminated because the respondents were worried about their tax situation and afraid that the economic details might be referred to the government. That was a very sensitive issue for them in this research. Blood cholinesterase activity in the sprayers was measured. First of all, both the Tintometric method and the Cholinesterase B test were used to examine blood cholinesterase activity to obtain baseline data. Secondly, only the Cholinesterase B test was used on blood samples after pesticide application training two months later. This was because the Shell Oil Company offered to participate only in the pre test. However, the differences in results between the two methods used in the pre-test were non-significant. If an interview is the most appropriate means of data collection, and the questionnaire has been pretested and designed to gather this information, the next step is selecting interviewers for the main study. In selecting these individuals, a researcher should consider the demographic characteristics of the interviewers, such as age, sex, education, etc., which would support and help in the matching of interviewer and respondent. The interviewers in this research project were preselected on the basis of their educational background and experience in assessing general information from respondents about demographic characteristics of experimental and control groups in a sample. The interviewers were trained prior to the observations of the sprayers. An interviewer's personal appearance should make a positive first impression on potential respondents. This may determine whether or 57 not they agree to participate. In a developing country like Thailand, wearing a governmental uniform would bias the kinds of responses villagers would give. Dress should be appropriate to the type of responses desired. In this research, the agricultural officers did a walk-through survey and collected data by using a checklist. They did not wear uniforms daily, except when they had a conference or meeting. This made the workers familiar with them, and thus it was easier to obtain observations of actual behavior in using pesticides by checklist questionnaire. The interviewers visited any orchid nursery whenever they wanted and had no specific time for their visits. The owners were not prepared before the observations of safety practices in use or storage of pesticides. Twelve university graduates in social sciences who had some working experience in face-to-face interviewing were used for this study. Even though these interviewers had such experience, we reviewed the following points with them: the role of an interviewer, how to handle the first meeting with the respondent, questions commonly asked by respondents (purpose of survey, who is responsible for survey, how to find out more about the survey, limits of confidentiality), confidentiality procedures, appropriate setting for the interview, techniques for building rapport, how to ask the questions (e.g., consistently ask questions exactly as they appear on the interview schedule), how to deal with pauses, when to probe and types of probes that are acceptable (e.g., probes should be neutral), how to record responses (e.g., paraphrasing is not permitted as it may distort the response), checking the questionnaire (e.g., this should be done 58 immediately after taking leave of the respondent), how to end an interview. The interviewers were provided with a training course to maximize their consistency in interview delivery. The training course included three hours of classroom instruction. Interviewers were also assigned practice interviews in the field. An intensive course was held emphasizing a working knowledge of using pesticides correctly, the specific objectives of the study, data collection and interviewing techniques. All of the questions in the interview schedule were reviewed to ensure that the interviewers clearly understood the intent and flow of the questions. A structured interview schedule with close ended questions was prepared to encompass all variables listed for the descriptive and analytic study. In order to obtain highly valid and reliable data, we established contact with the agricultural officers in each sub-province and gave them some planning information, including date and time to let them know when to lead the interviewers to the owners of orchid nurseries, so that they could plan to do their field observations one week later. The Hawthorne Effect (Roethlisberger &Dickson, 1939)--workers knowing that they are being observed change their behavior--was kept in mind when designing this field research, because the orchid workers would not behave "naturally" when they knew they were being observed and studied. Finally, the agricultural officers chose the best possible means for collecting observational data. The duties of the agricultural extension officials were to solve the problems about pest diseases and fertilizer and to arrange exhibitions of orchids for 59 export companies and the nurseries. Therefore, the nursery workers tended to behave more naturally because they might have thought that the agricultural officials had come to suggest useful things rather than to observe their behavior. Since this study was conducted in a field context, several potential problems, including limited resources and limited time, were evident. Therefore, in cases where the original respondents were found to be away during the study or otherwise not available for interview, they were dropped. Each day, the collected information was edited and corrected, and at the same time the data were entered into the SPSS-PC+ program. Whenever we encountered cases in which we had questionable information, improperly coded answers, or missing data, the samples were re-interviewed by the same inter viewer at the earliest possible opportunity. In this second interview, only the problematic items were included. Furthermore, in the coding of data for analysis, nominal or categorical codes were chosen for some continuous data due to the fact that many of the respondents preferred to use ranges of data in their answers. This preference was related to the respondents' educational level. Measures of association were collected through the questionnaires. The data consisted entirely of categories of cases. Therefore it was most appropriate to use chi-square analysis. There were a large number of variables, some of which were very complex. However, variables which were not associated with dependent variables or not substantively important variables were left out. However, in the case of multivariate data, there were few associated variables. A Smallest Space Analyses (SSA) and/or 60 Multidimensional Scalogram Analysis (MSA) might allow for further analyses of the underlying structure of the data (Guttman, 1968). Researchers try to ensure that their research findings are relatively free of error and that the observations are able to achieve this objective. Rosenthal and Rosnow (1984) concluded that there are three criteria to approach in research design: "One criterion, termed validity, essentially means the degree to which we observe what we purport to observe. The second criterion, reliability, is the degree to which our observations are consistent or stable. The third criterion, precision, refers to the sharpness or exactness of our observations" (p. 76). The less error there is, the more reliable the observation, and so a measurement that is free of error is a correct measure. In this study, the questionnaire had a pre-test for the different groups, and inappropriate questions were rewritten.
Biological Monitoring of Agricultural Workers Exposed to Pesticides; Cholinesterase Activity in Other Countries
Both plasma and erthrocyte cholinesterase have been used as indices of exposure assessments of low-level chronic residue exposure among fie1dworkers. Jeyaratnam, Lun and Phoon (1986) noted that whole blood cholinesterase activities were determined (by Edson's tintometric method) for agricultural pesticide users exposed to organophosphorus compounds in Indonesia, Malaysia, Sri Lanka and Thailand. Analysis of the data demonstrated a universal relat~onship between cholinesterase 61 levels and the time between the last exposure to organophosphorus compounds and the day of blood collection for cholinesterase determin ation. It is suggested that
it takes approximately 5 days before blood cholinesterase levels revert to their normal values. Blood samples were collected from a total of 1,383 randomly selected subjects, and analysis was performed in the field. Data analysis indicated that 45.7 percent and 45.2 percent of the workers in Sri lanka and Malaysia, respectively, had whole blood cholinesterase values of 75.0 or lower on the tintometer scale, whereas in Indonesia and Thailand, only 17.2 percent and 1.5 percent, respectively, had such whole blood cholinesterase values. A universal relationship was seen between whole blood cholinesterase levels and the time between last pesticide exposure and day of blood collection and analysis. In Malaysia, after an average of 5.2 days, all pesticide users had whole blood cholinesterase levels of 87.5 to 100.0; the difference in whole blood cholinesterase levels between agricultural workers and controls was statistically significant. No relationship was seen between blood cholinesterase level and age or sex of the workers. (pp. 195-201)
Regeneration of plasma activity is more likely to be seen during this short period because of its more rapid rate of recovery. Further increases on subsequent determinations would confirm the diagnosis. The workers affected should be kept from work involving exposure to these chemicals until their red cell cholinesterase has regenerated. Erythrocyte rather than plasma values are recommended as the end point because the former better reflect physiological effects on the nervous system. In determining when regeneration has been completed, consider ation should be given to the fact that the red cell cholinesterase activity of a healthy person may normally vary by 10% upon retesting. If a value increases by more than 10% over a value drawn ten days 62 previously (using the conservative estimate of 1% per day for red cell cholinesterase recovery), the baseline may not yet have been reached. In most cases, agricultural workers are forced to return to work for economic reasons long before their red cell cholinesterase can be demonstrated to have completed regeneration and very often before their symptoms have completely resolved (Coye, 1986). In addition to the acute symptoms of cholinergic excess, eNS symptoms are often seen as sequelae to cases of acute poisoning, and in association with chronic exposures to low levels of organophosphates. When these nonspecific symptoms were investigated in farm worker studies, group correlations were found between the prevalence of symptoms and the moderate levels of cholinesterase inhibition encountered, presumably reflecting the association between inhibition as an index of exposure and this effect. Neither the presence nor the severity of these symptoms are well correlated with cholinesterase inhibition for individuals (Levin, 1976).
Cholinesterase Activity
Cholinesterase is an enzyme that hydrolyzes choline esters and is found mainly in nerve junction. The most widely accepted method for establishing organophosphate/carbamate exposures is to measure the cholinesterase levels in the blood of the patients known or suspected of having been poisoned. There are many methods available for the assay of blood cholinesterase. These may be classified into two types: rapid screening methods and methods requiring a well trained laboratory staff and special equipment (see Appendix C). 63 Health and Safety Program in the Experimental Group
The purpose of this program was to help the participants under stand the hazards to pesticide applicators by oral contact, inhalation, or skin exposure and learn how to protect themselves; learn first aid for accidents in using pesticide; and know how to use pesticides corectly and how pesticides work, including the following: (1) mixing and storage of pesticides, (2) how to properly handle damaged con tainers, (3) becoming aware of pesticide residues in the environment. The essential things are how to choose, use, and care for equipment to increase safety in spraying pesticide. We tried to help them to recognize how pesticide labels can help them by following instructions given for maintaining a safe environment in the handling of pesticides. In every category, we provided slides and selected only the protective equipment that could be applied in agricultural work: goggles, mask, respirator, and head covering. We also included mask, gloves and boots that we borrowed from an equipment company which sold such protective equipment to industrial workers but which could be used in agriculture. We wanted the sprayers to touch or try to put on the equipment so that they would have a better idea of what each piece of equipment looked like. We prepared a health and safety booklet, which is included in Appendix G, and gave it only to the experimental group.
Pest Controlling Program in the Control Group
The purpose of this program was to help the participants under stand about the variety of chemicals available on the market for the control of pests and diseases. Generally, each chemical may be 64 effective and specific for the control of a particular pest or disease. It is very important that we know at least how to diagnose the trouble before using any chemical. We tried to helm them understand the most common features of pests--how they develop and the kinds of damage they do--and also analyze the various types used to control pests and how to combine these types for the best results, including how to mix pesticides among wettable powders, emulsifiable concentrates (powder mixed with water solution), liquid concentrates and flowable formula ti ons •. We remi nded them that when they mi."eed more than two or three kinds of pesticides together and sprayed them at the same time because they wanted to save time, they would be using an overload dose of pesticide that is useless, because it makes pests resistant to pesticides, and therefore would cause the sprayers to lose the cost benefit of pesticides. Therefore a proper formula should be used during a pest outbreak. In summary, a discussion of the research design, including sampling methods and sample size, has been presented. The next chapter focuses on the details of the population, socio-demographic characteristics of the sample, knOWledge, attitudes and practices related to actual behavior regarding pesticide application, and findings concerning the results of the blood cholinesterase cases. 65
CHAPTER IV RESEARCH FINDINGS
This chapter presents the descriptive findings of the study. The focus of the discussion is on the socio-demographic characteristics of the sample and the knowledge, attitudes, and practices related to actual pesticide application behavior. In addition, summaries of findings concerning blood cholinesterase assessments using the Cholinesterase B method will be presented.
Study Focus
Amajor focus of this study is identifying factors that help to explain why people use or fail to use protective equipment and to attempt to alter those patterns. This is of interest because many organophosphorus pesticides can readily penetrate the skin and eyes, and thus enter the body. Both male and female orchid nursery workers were interviewed in this study. Their ages were from 20-60 years and they lived in selected areas surrounding Bangkok. Respondents examined were in reasonably good health and had similar educational and social back grounds. The participants were divided into experimental and control groups. Each lived and worked in one of the two locations used in the study. These locations were quite similar in climate and geography but far enough apart to insure no easy transfer of information between groupings. The experimental and control groups lived at least 24 miles from each other (Figure 4.1). 66
EPC 0 THE EXPERIMENTAL OROUP
ETC EPC· PHASI CHAROEN' 9 0 ETC· TAUNO CHANO ENK • NONO KHAEM ENK 15 18 0 CKB 36 33 24 0 THE CONTROL OROUP CKB • KRATHUM BAEN CBP 60 57 51 24 0 CBP • BAN PHAEO cSP • SAM PHRAN csp 30 39 27 18 36 0 EPC ETC ENK CKB CBP csp
Figure 4.1. Mileage Distance Chart in Both Experimental and Control Groups 67 Orchid nursery farms in Thailand range from large farms with many workers to small nurseries in which the family helps to take care of the orchids. There is a profitable business in exporting orchids to many European countries and to Japan. For this reason, many farm owners have started to grow orchids for export. There are now a lot of areas in Bangkok and nearby where population samples could be collected. Our experimental samples came from the following places: --Phasi Charoen region: Bangpie, Bangklanige, Bangkla and Khongkuang subdistricts; --Taling Chang region: Banglamard, Bangchiuknag, Bangprom, Saladang, and Tanweewatana subdistricts; --Nong Khaem region: Luksong, Nongkhangphlu and Nong Phaem subdistricts. The control samples were collected in Samut Sakorn province: --Krathum Baen district: Bangyang, Suanlonge, Khongmardire, Thaseo, Thamae, Thatarate and Nongnaugkhi subdistricts; --Banplang district: Suansom, Khaseadpatana, Khongton, Nongbrue, Nongsonghong and Luksam subdistricts; and also in Nakorn Pathom province: --Samphran district: Samphran, Raikhing, Krathumloum, Krathumsmal, and Aoumyai subdistricts. (See map in Appendix E.)
Description of the Management of Data
Missing Case Analysis (Lost Cases Analysis)
The design of this study became extremely complicated in terms of the tracking of its cases. This was because many of the cases 68 dropped out of the study during the health and safety training program or the pest control program or when blood samples were collected. In addition to the groups under study, an unexposed control group was used to provide a standard for blood cholinesterase activity. In the post-test process, we planned to collect blood samples twice, before spraying and after spraying. However, some of the cases changed their minds and were dropped from the collection of blood samples. Tables 4.1 and 4.2 illustrate the coding system used to track cases in this study. To make it somewhat easier to follow, Figure 4.2 is presented as a flow chart to show where cases went. The total study sample was 922 cases. There was an experimental group of 270 cases, a control group of 250 cases, an unexposed control group of 296 cases, and a group of 106 workers who only gave blood samples. The experimental group was divided into a health and safety training (H-TR) subgroup of 80 cases, and a non-health and safety training (NH-TR) subgroup of 190 cases, as shown in Table 4.1. Although non-health and safety training subgroups are listed here to show the division of the experimental group, in data analysis these subgroups were treated as controls. The control group was divided into a pest disease controlling (P-TR) subgroup of 39 cases and a non-pest disease controlling (NP-TR) subgroup of 211 cases, as shown in Table 4.2. 69 Table 4.1 How the Population in the Experimental Group was Divided
Owner Worker Group Coding (cases) (cases)
Health and H-TR-BL 56 14 safety TRaining &BLood sample
Health and H-TR-NBL 8 2 safety TRaining &Non-BLood sample Non-Health and NH-TR-BL 105 15 safety TRaining &BLood sample Non-Health and NH-TR-NBL 60 10 safety TRaining &Non-BLood sample POSt-test &Health POS-H-TR-BL 56 14 and safety TRaining &BLood sample Non-(POSt-test) NPOS-H-TR-NBL 6 &Health and safety TRaining & Non-BLood sample POSt-test &Health POS-H-TR-NBL 2 1 and safety TRaining &Non-BLood sample POSt-test & POS-NH-TR-NBL 4 1 Non-Health and safety TRaining &Non-BLood sample Non-(POSt-test) & NPOS-NH-TR-BL 105 15 Non-Health and safety TRaining &BLood sample Non-(POSt-test) & NPOS-NH-TR-NBL 56 9 Non-Health and safety TRaining &Non-BLood sample 70
Table 4.2 How the Population in the Control Group was Divided
Owner Worker Group Coding (cases) (cases)
Pest disease P-TR-BL 35 4 conTRolling & BLood sample Non-Pest disease NP-TR-BL 126 13 conTRolling & BLood sample Non-Pest disease NP-TR-NBL 66 6 conTRo 11 i ng & Non-BLood sample
POSt-test &Pest POS-P-TR-BL 17 2 disease conTRolling &BLood sample Non-(POSt-test) NPOS-P-TR-BL 18 2 &Pest disease conTRo 11 i ng & BLood sample Non-(POSt-test) & NPOS-NP-TR-BL 126 13 Non-Pest disease conTRolling &BLood sample Non-(POSt-test) & NPOS-NP-TR-NBL 55 6 Non-Pest disease conTRolling & Non-BLood sample POSt-test & POS-NP-TR-NBL 11 0 Non-Pest disease ConTRolling & Non-BLood sample r-- -r----1ISTUDY POPULATION I UNEXPOSED CONTROL I I IN.922 I . N• 296 --- I I NH-TR I WORKER ONLY BLOOD I IN.190 I CONTROL GRJ N • 106
H-TR-NB~ (0).8,(W~ i' NPOS-NH-TR-BL P08-H-TR-BL (0) • 105, (W) • 15 (0) • 66, (W) • 14
POS-H-TR-HBl NP08-H-TR-NBl HPOS-NH-TR-NBL (0) • (W) • 1 (0) • 2, (W) • 1 e, (0) • 58, (W) • 0
Figure 4.2. Flow Chart of Cases in Study
"'-J ~ 72 Coding of the Data In this study, data coding was done by the field supervisors with the assistance of the researcher. The final editing and data entry done using the SPSS-PC+ software package (Norusis, 1988). Thus, the total number of variables for any analysis could not exceed 200, meaning that several data sets had to be created and then merged for specific analyses.
Description of Study Population Our socio-cu1tura1 approach to the study population emphasizes the importance to health behavior of health values, lifestyles, and health or medical orientations. For example, sex, age, and education are all associated with seeking care behavior or utilization behavior. The general characteristics of the respondents of this research are all presented in the following set of tables. Table 4.3 shows that more than 20% of the owners and less than 5% of the workers are over 50 years old; the owner group is older than the worker group. Most typically, the owners are 25-39 years old and the workers are 20-29 years old. Table 4.4 presents the number of males and females in the experimental and control groups. There are more males than females in both groups; there are more than four times as many males as females. Married subjects, as shown in Table 4.5, are more frequent in both experimental and control groups; however, while the owners have a high proportion of married people in both groups, the workers have a high proportion of single people in the experimental group. Table 4.6 shows similarities in education for both the experimental and control groups; however, a higher proportion of owners than of workers finished grade 4, which suggests that the owners are better educated than the workers. Table 4.3 Comparison of Age Characteristics of the Experimental Group and the Control Group for all Cases
Experimental Group Control Group Age H(O) H(W) NH(O) NH(W) P(O) P(W) NP(O) NP(W) Total <19 l( 12.5) 7(87.5 - - 2( 50.0) 2(50.0) 12( 2.4) 20-24 19( 63.3) nt36.7) - - 16( 72.7) 6(27.3) 52(10.2) 25-29 29( 80.6) 7(19.4) l(100.0) - 40( 93.0) 3( 7.0) 2( 66.7) 1(33.3) 83(16.3) 30-34 36( 94.7) 2( 5.3) - - 34( 82.9) 7(17.1) 79(15.6) 35-39 32 ( 94.1) 2( 5.9) l( 50.0) l(50.0) 30( 93.8) 2( 6.3) l(100.0) 69(13.6) 40-44 25( 89.3) 3(10.7) - - 30( 90.9) 3( 9.1) l(100.0) 62(12.2) 45-49 26( 92.9) 2( 7.1) - - 22(100.0) 3(100.0) 53(10.4) 50-54 18( 90.0) 2(10.0) 2(100.0) - 27(100.0) 4(100.0) 53(10.4) 55-59 12(100.0) 1(100.0) - 5(100.0) 1(100.0) 19( 3.7) 60-60+ 17(100.0) 9(100.0) 26( 5.2) Total 215( 90.3) 36(14.3) 5( 83.3) 1(16.7) 215( 90.3) 23( 9.7) 12( 92.3) 1( 7.7) 508(100.0)
H(O) /H(W) = Health and Safety Training for Owner/Worker NH(O)/NH(W) = Non-Health and Safety Training for Owner/Worker P(O)/P(W) = Pest Disease Control Training for Owner/Worker NP(O)/NPnO = Non-Pest Disease Control Training for Owner/Worker
...... w Table 4.4 Comparison of Sex Characteristics of the Experimental Group and the Control Group for all Cases
Experimental Group Control Group Sex H(O) H(W) NH(O) NH(W) P(O) P(W) NP(O) NP(W) Total
Male 181(86.2) 29(13.8) 5(83.3) 1(16.7) 168(89.8) 19(10.2) 10( 90.9) 1(9.1) 414( 81.3) Female 35(83.3) 7(16.7) - - 47(92.2) 4( 7.8) 2(100.0) - 95( 18.7) Total 216(85.7) 36(14.3) 5(83.3) 1(16.7) 215(90.3) 23( 9.7) 12( 92.3} 1(7.7) 509(100.0)
H(O)/H(W) = Health and Safety Training for Owner/Worker NH(O}/NH(W} = Non-Health and Safety Training for Owner/Worker P(O}/P(W) = Pest Disease Control Training for Owner/Worker NP(O)/NP(W) = Non-Pest Disease Control Training for Owner/Worker
...... ~ Table 4.5 Comparison of Martital Status Characteristics of the Experimental Group and the Control Group for all Cases
Marital Experimental Group Control Group Status H(O) H(W) NH(O) NH(W) P(O) pew) NP(O) NP(W) Total
Married 163(91.6} 15( 8.4} 4(100.0} - 163( 91.6} 15{ 8.4} 12(92.3} 1(7.7} 373( 74.0} Single 50(71.4} 20(28.6} 1( 50.0} 1( 50.0} 48( 85.7} 8(14.3} 128( 25.4} Other* 3( 66. 7) 1( 33.3} - - 4(100.0} 8( 0.6} Total 216(85.7) 36(14.3} 5(83.3} 1(16.7} 215( 90.3} 23( 9.7} 12(92.3} 1(7.7) 509(100.0)
*Other includes widowed, divorced, and separated
H(O)/H(W) = Health and Safety Training for Owner/Worker NH(O)/NH(W) = Non-Health and Safety Training for Owner/Worker P(O)/P(W) = Pest Disease Control Training for Owner/Worker NP(O)/NP(W) = Non-Pest Disease Control Training for Owner/Worker
...... U1 Table 4.6 Comparison of Education Characteristics Between the Experimental Group and the Control Group for all Cases
Educa- Experimental Group Control Group tion H(O} H(WO} NH(O} NH(W} P(O} P(W) NP(O) NP(W) Total
A* 15( 62.5} 9(37.5) 6( 75.0) 2(25.0) -- 34( 7.9) B* 114( 89.8) 13(10.2} 2(100.0) 115( 88.5) 15(11.5) 6( 85.7) 1(14.3) 266( 65.8) C* 38( 77.6) 11(22.4) 1( 50.0) 1(50.0) su 94.4) 3( 5.6) 1(100.0) - 106( 16.8) D* 40( 97.6) 1( 2.4) -- 35( 92.1) 3( 7.9) 5(100.0) - 84( 7.2) E* 8(100.0) 2(100 .0) 8(100.0) - - - 18( 2.3) Total 215( 86.3) 34(13.7) S( 83.3) 1(16.7) 215( 90.3) 23( 9.7) 12( 92.3) 1( 7.7) 508(100.0)
~ = Less than Grade 4 i3 = Finished Grade 4 i: = Finished Grade 6 i) = Finished High School i: = Attended University
H(O)/H(W) = Health and Safety Training for Owner/Worker NH(O)/NH(W) = Non-Health and Safety Training for Owner/Worker P(O)/P(W) = Pest Disease Control Training for Owner/Worker NP(O)/NP(W) = Non-Pest Disease Control Training for Owner/Worker
""-J (J'l 77 Table 4.7 shows a high proportion of those who worked on other farms before the orchid farm in both the experimental and control groups; a higher proportion of owners than of workers had a history of work on other farms. Table 4.8 shows that the most common length of time spent spraying in both the experimental and control groups was two hours per day. Additional data were collected about the smoking habits in the experimental and control groups. There was a high proportion of non smokers among both the owners and the workers. Most (>65.0%) did not smoke. There was a high proportion of non-drinkers in both the experimental and control groups and a high proportion of beer drinkers among the drinkers in both the experimental and control groups. All the details above show the demographics of the orchid sprayers in both the owner and worker groups. In total, 73.1% of all subjects were owners and 26.9% were workers. The spraying group comprised 15.2% of all subjects, the mixing group 16.8%, and the mixing and spraying group 68%. The experimental health training group comprised 41.8% of all subjects, the non-trained experimental group 1%, the pest training control group 38.5% and the non-trained control group 18.7%. The percentages of the blood test groups are divided in seven groups as follows: the blood sample taken at pre-test group 26.1%, the sample for pre-test and post-test (before spraying) group 0.8%, the sample for pre-test and post-test (after spraying) group 8.4%, the sample for pre-test and post-test (before spraying and after spraying) group 10.6%, the sample for post-test (before spraying) group 0.5%, the post-test (after spraying) group 15.6%, the sample Table 4.7 Comparison of Working History Characteristics of the Experimental Group and the Control Group for all Cases
Work Experimental Group Control Group History H(O) H(W) NH( 0) NH(W) P(O) P(W) NP()) NP(W) Total
A* 50(80.6) 12(19.4) 3(100.0) 35(87.5) 5(12.5) l(100.0) 105( 20.7) B* 166(87.8) 23(12.2) 3( 75.0) 1(25.0) 180(90.9) 18( 9.1) 11( 91.7) 1(8.3) 403( 79.3) Total 216(86.1) 35(13.9) 5( 83.3) 1(16.7) 215(90.3) 23( 9.7) 12( 92.3) 1(7.7) 508(100.0)
*A =worked on orchid farm *B = worked on other farms before orchid farms
H(O)/H(W) = Health and Safety Training for Owner/Worker NH(O)/NH(\O = Non-Health and Safety Training for Owner/Worker P(O)/P(W) = Pest Disease Control Training for Owner/Worker NP(O)/NP(W) = Non-Pest Disease Control Training for Owner/Worker
--.J co Table 4.8 Comparison of Duration of Spraying Characteristics of the Experimental Group and the Control Group for all Cases
Hours Experimental Group Control Group per day H(O) H(W) NH(O) NH(W) P(O) P(W) NP(O) NP(W) Total
1 82( 90.1) 9( 9.9) 3(100.0) - 60( 89.6) 7(10.4) 2(100.0) - 163( 34.8} 2 102( 84.3} 19(15.7) 2(100.0) - 78( 88.6} 10(11.4} 5(100.0} - 216{ 46.1) 3 24( 77.4} 7(22.6} - l{100.0} 52( 94.5} 3( 5.5} 3(100.0} - 90{ 9.4} 4 4( 80.0} l{20.0} - - 15(100.0} - l{100.0} - 21{ 6.3} 5 4(l00.0) - - - 10( 76/9) 3(23.1) 1( 50.0) 1(50.0) 19( 3.4) Total 216( 85.7) 36(14.3) 5( 83.3) 1( 16.7) 215( 90.3) 23( 9.7) 12( 92.3) 1( 7.7) 509(100.0)
H(O)/H(W) = Health and Safety Training for Owner/Worker NH(O)/NH(W) = Non-Health and Safety Training for Owner/Worker P(O)/P(W) = Pest Disease Control Training for Owner/Worker NP(O)/NP(l~) = Non-Pest Disease Control Training for Owner/Worker
..... \0 80 for post-test (before spraying and after spraying) group 13%, and the non-blood sample group 25%. Finally, only 19.7% of all respondents took the mid-test, while 80.3% did not. The socio-demographic characteristics of the sample provide a picture of the study population and also serve to help understand factors which may determine knowledge, attitudes, and actual behavior of the sample. The knowledge levels of the appropriate use of protective clothing for subjects before training are shown in Table 4.9. Correct responses range from 28% to 91.5%, with about 60% being the average proportion correctly responding across all items.
Table 4.9 Knowledge Levels of the Appropriate Use of Protective Clothing for all Subjects before Training
Content Number Correct Knowledge %
Long Pants 508 433 85.2 Long Sleeves 509 461 90.6 Necessary Raincoat 499 214 42.9 Boots 508 142 28.0 Necessary Hat 508 465 91.5 Necessary Mask 507 417 66.1 Necessary Gloves 508 163 32.1 81 The proportion of respondents giving correct answers (Figure 4.3) increased from the pre-test to the mid-test declined somewhat «20%) by the post-test. However, the increase from pre-test to post-test shows that there was some retention of knowledge over the long term. Further, for some items (long pants, long-sleeved shirt, and hat) the scores on the pre-test were over 50%. When there is good knowledge to begin with, it is difficult to increase that knowledge. The owners had a high score for knowledge at the pre-test; they knew a lot already. When they got the new knowledge in the health and safety training, the mid-test scores were slightly before the pre test. This might be due to an error of measurement, the owners' confusion about the content of the health and safety program. For example, when we asked about the use of long pants in the pre-test, they answered "yes," but after the health and safety training finished, they changed to "no" because they had never used the kinds of protective clothes like those displayed in the training. However, two months later, they forgot about what they had been shown, and they went back to the right choice. There was the same pattern for the use of boots; they thought that the boots displayed in the training were military style, and would make it difficult for them to walk on a dirt pathway. The workers had different patterns than the owners, in that the mid test was higher than the pre-test. It seems that they easily trusted the information and they would make the right choice, but after two months, they forgot their knowledge and then would make the wrong one. Large differences existed between owners' and workers' scores (Figure 4.4). Owners' scores were at least 4-5 times greater than 82
'20r------,.-----, 120
PANTS SLEEVES RAINCOAT BOOTS HAT MASK GLOVES
_PRE-TEST _ MtDTEST I>} POST-TEST
Figure 4.3. Percentages of Correct Responses in Knowledge Pre-, Mid-, and Post-Tests for All Subjects 83
100 r------,
80 .- - -'- - :::::
60 -- _! \: __ __ Ii -- -}: 40 ";::' .:::. <:' '.; 20 J
o PANTS SLEEVES RAINCOAT BOOTS HAT MASK GLOVES
_ PRE(O) _ PRE(W) II MID(O) _ MID(W) 1mba POST(O) o POST(W)
Figure 4.4. Comparison of Owners' and Workers' Percentages of Correct Responses in Knowledge Pre-, Mid and Post-Tests 84 workers' scores. Also, the owners' scores showed an increase in the post-test; post-test scores were at least 4 and sometimes 5 points greater than the mid-test scores, which were much lower than either pre- or post-test scores. It seems that the owners felt that they received knowledge in the training program; they would think about what is right or wrong and consider what they should believe. The workers' scores followed a pattern which showed that the pre-test scores were lower than the mid-test scores which in turn were lower than the post-test scores. It seems that in the mid-test the workers were able to recall the content that we presented and they could select the right choices, but they forgot quickly. Individuals evaluated their attitudes towards the use of protective equipment for personal safety in view of the toxicity of pesticides, as shown through the attitude scales. These scales used Osgood's technique. The attitude levels towards the appropriate use of protective clothing for subjects before training are shown in Table 4.10. Here, the proportion of correct responses range from 22% to 79.8%, with about 50% being the average proportion correctly responding across all items. It appears that "addttive" protective clothing (e.g., gloves, goggles, raincoat, etc.) is less often seen as lIappropriatell protective clothing than basic clothing (e.g., shirt, pants, hat, etc.). In three out of six instances, the proportion of respondents giving correct answers (Figure 4.5) increased on at least four items on the mid-test (immediately after training) and declined somewhat «10%) by the post-test given two months later. 85 Table 4.10 Attitudes Towards the Appropriate Use of Protective Clothing for All Subjects Before Training
Content Number Correct Attitude %
Inconvenience of hat 510 285 55.9 Inconvenience of Mask 510 112 22.0 Gloves are Optional 510 184 36.1 Inconvenience vs Long Clothing 509 409 79.8 Difficulty of Raincoat 510 168 32.9 Boots are Optional 510 233 45.7
Large differences also existed between owners' and workers' scores (Figure 4.6) with owner scores at equal level between pre-test and post-test in four instances, at least 2 points higher in the pre-test than the post-test in one instance, and at least 2 points lower in the pre-test than the post-test in one instance. Worker scores followed a different pattern than that of all scores; for workers, pre-test scores were lower than the mid-test scores which were higher than the post-test scores. For owners, mid-test scores were lower than either pre-test or post-test scores in five instances. The pattern for attitude scores thus follows that for knowledge scores. The questionnaire focused on the respondents' practices in using pesticides and in using protective equipment. The statements were presented in terms of multiple choices. The practice levels for the appropriate use of protective clothing for subjects before training are shown in Table 4.11. We can see the proportion of correct 86
100 r------.
HAT MASK GLOVES LONG CLOTHES COAT BOOTS
_ PRE-TEST _ MIDTEST ';<1 POST-TEST
Figure 4.5. Percentages of Correct Responses in Attitudes Pre-, Mid-, and Post-Tests for All Subjects 87
10Qr------,
80
60
40
20
o HAT MASK GLOVES LONG CLOTHES COAT BOOTS
• PRE(O) _ PRE(W) rz::J MID(O) • MID(W) Emml POST(O) o POST(W)
Figure 4.6. Comparison of Owners' and Workers' Percentages of Correct Responses in Attitudes Pre-, Mid and Post-Tests 88
Table 4.11 Practice Levels of the Appropriate Use of Protective Clothing for All Subjects Before Training
Content Number Correct Practice %
Long Pants 510 409 80.2 Long Sleeves 510 456 91.2 Boots 189 84 44.4 Use Other Protection 509 485 95.3
responses ranges from 44.4% to 95.3%, with about 78% being the average proportion correctly responding across all items. The proportion of respondents giving correct answers (Figure 4.7) in practices increased at the mid-test on all items: using long pants, long-sleeved shirt, and boots, and using other protective equipment including hat, head covering, goggles, mask and gloves. However, the scores declined somewhat (20%) by the post-test. Large differences existed between owners' and workers' scores (Figure 4.8), with owners' scores at least 4-5 times greater than workers' scores in the post-test. For the owners, in at least three items the post-test was greater than the mid-test, but the mid-test was lower than the pre-test. Workers' scores were different from the owner pattern. The pre-test score was lower than the mid-test score which was higher than the post-test score. It may be that the owners were older and had a higher education than the workers, and that they needed to integrate the knowledge from the health and safety training 89
120 r-.------'--...,
PANTS SLEEVES BOOTS OTHER EQUP.
_ PRE-TEST _ MIDTEST 0 POST-TEST
Figure 4.7. Percentages of Correct Responses in Practice Pre-, Mid-, and Post-Tests for All Subjects 90
100 -.------,
80
60
% 40
20
o PANTS SLEEVES BOOTS OTHER EQUP.
_ PRE(O) _ PRE(W) o MID(O) _ MID(W) imml POST(O) o POST(W)
Figure 4.8. Comparison of Owners' and Workers' Percentages of Correct Responses in Practices Pre-, Mid-, and Post-Tests 91 before they could work out and apply in practice the use of protective equipment in the correct way. The pre-test and mid-test seemed to indicate that they were skeptical about using new techniques and felt confused in their answer choices. Workers' scores were different from the owner pattern. The pre-test scores were lower than the mid-test scores which were lower than the post-test scores. The workers' scores suggest that they fed back whatever we wanted them to learn. They appeared to remember the. contents immediately afterwards, but they never really understood why they should use protective equipment and finally could not retain their new knowledge. The pattern for practice scores thus follows that for knowledge scores. Our final piece of descriptive data of this sort is from the observations made by the agricultural field workers. The observation levels regarding the appropriate use of protective clothing for subjects before training are shown in Table 4.12. The proportion of correct responses ranges from 5.7% to 95.6%, with about 39% being the average proportion correctly responding across all items. The proportion of respondents observed using correct methods (Figure 4.9) increased at least 7 points over the scores on the pre test for five items after two months training. Large differences existed between owners' and workers· scores (Figure 4.10), with owners' scores at least six times greater on the pre-test and post-test than worker scores. For owners, post-test scores were lower on at least three itmes (gloves on-mix, gloves on-spray and long pants) than pre-test scores. Perhaps the owners were perplexed about what they wanted to use for protective equipment and 92
Table 4.12 Correct Practices Observed at Pre-Test (Before Training)
Content Number Correct Practice %
Hat 525 379 72.2 Goggles 525 40 5.7 Mask 525 244 46.5 Gloves on-Mix 525 36 6.9 Gloves on-Spray 525 35 6.7 Raincoat 525 502 95.6 Long Sleeves 525 493 93.9 Long Pants 525 72 13.7 Boots 525 46 8.8 93
100 ...------,
80
HAT GOGGLES MASK GLO MIXGLO SPA. COAT SLEEVES PANTS BOOTS
_ PRE-TEST _ POST-TEST
Figure 4.9. Percentages of Correct Practices for All Subjects Observed at Pre- and Post-Tests 94
120 r------,
100
HAT GOGGLES MASK GLO M. GLO SPA. COAT SLEEVES PANTS BOOTS
• PRE(O) _ PRE(W) 0 POST(O) III POST(W)
Figure 4.10. Comparison of Owners' and Workers' Percentages of Correct Practies Observed at Pre- and Post-Tests 95 what they learned or knew from the training, and they could not accept some of the equipment which caused them discomfort in their work. However, the total items of the owners' scores on the post-test were better than the pre-test, which suggests that the owners followed good practices after they learned the new ways. The workers' scores followed a different pattern from the owners' on all items. The pre test score was higher than the post-test score on at least six items but in at least three items the pre-test score was lower than the post-test score. The workers, being less educated than the owners, only believed what we told them, never thinking about why we recommended that they use protective equipment. Finally, it appears that they could not retain the practices, as we noted when we observed them later. The comparison of knowledge, attitudes, practices, and behavioral observation levels in the appropriate use of protective clothing on the pre-test and post-test is shown in Figure 4.11. We can see that the high proportion of correct responses in the knowledge post-test was better than the pre-test, the attitude pre-test was a little lower than the attitude post-test, the practices pre-test was about equal to the practices post-test, and behavioral observation on the post test showed an improvement over the pre-test. The total pattern in both the experimental and control groups in knowledge, attitudes, practices and behavioral observation showed that, in general, the subjects got the message about new ways, tried to find out the truth, and finally realized what the correct way was. When they went to work, they knew about the equipment which was 96
100r------..,
KNPRE KNPOS PRPRE PRPOS ATPRE ATPOS OPRPREOPRPOS
_SAD _FAIR o GOOD
Figure 4.11. Comparison of Data in Pre-Tests and Post-Tests for Knowledge, Attitudes, Practices and Observation for Both Groups 97 suitable for them. However they needed to have more practice in how to use the equipment and help in solving their problems. Figure 4.12 and Figure 4.13 show the total pattern of the difference between the owners and the workers in five ranges of total scores: very bad, bad, fair, good, very good. Owners' scores were 3-4 times greater than the workers' scores. The owners had a higher proportion correct on the post-test for attitudes, practices, and observations, while the workers had a lower proportion correct. It seems that the owners understood how to protect themselves in an appropriate way. The workers, however, remembered and believed what we taught them, but did not understand the content clearly. They had no idea what it was but they felt sure that it must be good, and so they started to memorize it but finally could not retain it. A comparison of the results of the cholinesterase levels in the pre-test, post-test before spraying, and post-test after spraying are shown in Figure 4.14. There are three ranges: low, normal, high. The low levels which were shown in the post-test before spraying and the post-test after spraying were due to accumulations of pesticides which remained in the field. It seems that the post-test before spraying and the post-test after spraying show the same low range of cholinesterase level in both groups of owners and workers, as shown in Figure 4.15. Figure 4.16 shows a comparison of results of cholinesterase levels in factory and agricultural workers. Most of the pre-test and factory workers were at normal level but both the post-test before spraying and the post-test after spraying workers had low levels of 98
100r------,
80
40
o VB.(O) VB.(W) B.(O) B.(W) F.(O) F.(W) G.(O) G.(W) VG.(O) VG.(W)
• KNPRE _ KNPOS 0 ATPRE Iii ATPOS
Figure 4.12. Comparison of Data in Pre-Tests and Post-Tests for Knowledge and Attitudes in Owners' and Workers· Groups 99
120 r------.
100
60
40
20
OL--~-..J..oL.- VB.(O) VB.(W) B.(O) B.(W) F.(O) F.(W) G.(O) G.(W) VG.(O)VG.(W)
- PRPRE _ PRPOS DOBSPRE _ OBSPOS
Figure 4.13. Comparison of Data in Pre-Tests and Post-Tests for Practices and Observation in Owners' and Workers· Groups 100
80------,
60
% 40
20
01....-.1-- LOW NORMAL
_ PRE-TEST _ POST-BS 0 POST-AS
POS-BS = Post-Test Before Spraying in Agricultural Worker POS-AS = Post-Test after Spraying in Agricultural Worker
Figure 4.14. Comparison of Cholinesterase Results for Pre-Test and Post-Test 101
100 r------,
80
% 60
40
20
o LOW(O) LOW(W) NOR.(O) NOR.(W) HIGH(O) HIGH(W)
_ PRETEST _ POSBS 0 POSAS
POS-BS = Post-Test Before Spraying in Agricultural Worker POS-AS = Post-Test After Spraying in Agricultural Worker
Figure 4.15. Comparison of Cholinesterase Results for Pre-, Post-Before Spraying, Post-After Spraying Testing 102
120
100
80 % 60
40
20
0 LOW NORMAL
_ FACTORY _ PRE-TEST 0 POS-BS ..paS-AS
FACTORY = Factory Worker PRE-TEST = Pre-Test in Agricultural Worker POS-BS = Post-Test Before Spraying in Agricultural Worker POS-AS = Post-Test After Spraying in Agricultural Worker
Figure 4.16. Comparison of Cholinesterase Results for Factory and Pre-Test and Post Before and Post After Spraying 103 cholinesterase. Some of the factory workers had low levels but less than 40% of this number were found to have had potential pesticide exposures off their factory jobs. The baseline for blood cholinesterase consisted of 296 industrial workers who had never been involved with pesticide and acted as a control group for this aspect of the study. They varied in age from 20-39 years old, and consisted of 69.9% males and 30.1% females. Although there was a lower proportion of female to male than among the orchid workers, a balanced proportion was not believed to be necessary. Jeyaratnam, Lun and Phoon (1986) reported that "no relationship was seen between blood cholinesterase and age or sex of the workers ll (p. 201). The results of blood cholinesterase testing by the Cholinesterase B method gave a normal range (1140-1590 lUll) of 65.6%, and below normal range (660-1139 lUll) of 34.4%. When we compared with the orchid nursery worker, the results of blood cholinesterase testing by the Cholinesterase B method gave a normal range (1140-1590 lUll) of agricultural owners 81.4% and agricultural workers 77.8%, and below normal range (660-1139 lUll) of agricultural owners 18.6% and agricultural workers 22.2%. The questionnaire to investigate signs and symptoms of pesticide poisoning included the following variables: age, sex, and the frequency of spraying insecticide. The results showed that the workers sprayed once a week (68%) or twice a week (31.4%) at each farm and they had 1-5 people (84.5%) help them each time. The duration of spraying ranged from one hour (25.8%), two hours (34.2%), three hours (14.3%), and four hours (3.3%), to more than four hours (3.3%). They each had 1-4 II rai " or 0.4-1.6 acres (94.5%) of land. 104
Table 4.13 Data on Pesticide Exposure Obtained from Health Examinations of Orchid Workers After Spraying Pesticide
Sign and Symptom Number of Cases Percentage
Headache 2 0.60 Weakness 7 2.11 Skin irritation 12 3.63 Eye irritation 14 4.23 Sweating 19 5.74 Combined headache and dizziness 20 6.04 Combined thirst, throat irritation and sweating 36 10.88 Combined weakness, dizziness, vomiting, 22 6.65 salivating, tremors, sweating, thirst, and throat irritation Combined weakness, dizziness, skin 70 21.15 irritation, thirst and throat irritation No sign or symptom 129 38.97
Total 331 100.00 105 The data that we collected confirmed that the participants experienced the known signs and symptoms of pesticide poisoning. Also seen among the cases of exposure to pesticides was a slower than normal reaction to light by the pupils of the eyes. However, contrac tion of the pupils does not invariably occur, and it may result from the local effects of minute amounts of material in the eye with no other systemic reaction. Nurses noted that even some of the sprayers who used protective equipment showed signs and symptoms of pesticide poisoning. It seems that some of their protective equipment is not effective, and there is a need for the sprayers to find better equipment to protect themselves. Figure 4.17 shows the scores of appropriate protective equipment knowledge average of summed scores on the pre-test, mid-test, and post-test for owners and workers in the experimental and control groups. The mid-test scores and post-test scores were higher than the pre-test. For both owners and workers in the experimental and control groups there was this same pattern. Figure 4.18 shows the scores of approprite protective equipment attitudes average of summed scores at pre-test, mid-test, and post test for owners and workers in the experimental and control groups. The mid-test scores in the owners· experimental group were higher than the others and the mid-test scores in the owners· and the workers' control groups were equal to each other. It seems that the owners· attitudes showed a different pattern in the experimental group. The scores were higher after they had health training but were lower on the post-test (two months later), which had higher scores than the 106
4.------, 3.5
3
8CORE8 2
1.5
0.5 o EO EW CO CW
_ PRE-TEST _ MID-TEST 0 POST-TEST
EO • EXPERIMENTAL GROUP/OWNER EW • EXPERIMENTAL GROUP/WORKER
CO • CONTROL GROUP/OWNER CW • CONTROL GROUP/WORKER
Figure 4.17. Protective Equipment Knowledge Average of Summed Scores for Owners and Workers 107
7.------~
EO EW co CW
_ PRE-TEST _ MI D-TEST 0 POST-TEST
EO • EXPERIMENTAL GROUP/OWNER EW • EXPERIMENTAL GROUP/WORKER
CO • CONTROL GROUP/OWNER CW • CONTROL GROUP/WORKER
Figure 4.18. Protective Equipment Attitudes Average of Summed Scores for Owners and Workers 108 pre-test. In the control group, the scores were the same as pre-test scores after they had the pest identification (pest controlling), which did not involve the protective equipment. For the workers' attitudes in the experimental and control groups there was a different pattern. In the experimental group the scores were higher after they had health training and a little lower on the post-test (two months later); in the control group the scores were the same as pre-test scores after they had the pest identification but the post-test scores were a little higher than the pre-test. Figure 4.19 shows the scores of appropriate protective equipment practices average of summed scores at the pre-test, mid-test, and post-test for owners and workers in the experimental and control groups. The mid-test scores in the owners' experimental group were higher than the others and the mid-test scores in the owners' and the workers' control groups were a little higher than the pre-test and the post-test scores. It seems that the owners' practices showed a different pattern in the experimental group. The scores were higher after they had health training but were lower on the post-test (two months later), which had higher scores than the pre-test. In the control group, the owners' scores were a little higher than the pre-test scores after they had the pest identification (pest controlling) but much lower than the experimental group in both owners' and workers' scores. For the workers, in the experimental group the mid-test scores were higher after they had health training and a little lower on the post test (two months later), and in the control group the mid-test scores were a little higher than the pre-test scores after they had the pest 109
5,------,
EO EW CO CW
_ PRE-TEST _ MID-TEST 0 POST-TEST
EO • EXPERIMENTAL GROUP/OWNER EW • EXPERIMENTAL GROUP/WORKER
CO • CONTROL GROUP/OWNER CW • CONTROL GROUP/WORKER
Figure 4.19. Protective Equipment Practices Average of Summed Scores for Owners and Workers 110 identification and a little lower on the post-test. Between the pre test and the post-test, the experimental and control groups were alerted to the dangers of pesticides from the broadcase of a television and a radio program, which may have influenced them. The positive result in both owners and workers in the control group might be due to knowledge gained through these broadcasts. The other factor is the Hawthorne effect, in which they try to please their supervisors by improving their behavior. Figure 4.20 shows the scores of appropriate protective equipment use by observation average of summed scores at the pre-test, mid-test, and post-test for owners and workers in the experimental and control groups. Post-test scores in both owners· and workers' experimental and control groups had the same pattern: they were higher than pre-test scores. Although the post-test scores in the owners' and workers' control group were higher than the pre-test scores, these post-test scores were lower than the post-test scores of the experi mental group. Figure 4.21 shows the scores of Figures 4.17, 4.18, 4.19, and 4.20--appropriate knowledge, attitudes, practices and observation in protective equipment--average of summed scores at the pre-test, mid-test, and post-test for owners and workers in the experimental and control groups. The owners' and workers' experimental groups have the same pattern of knowledge, attitude, and practice scores: the mid-test was higher than the pre- and post-tests. However, the observation scores for the owners were much higher than for the workers. The owners' and workers' control groups have the pattern of knowledge 111
6r------,
5
4 8CORE
3
2
o EO EW CO CW
_ PRE-TEST _ POST-TEST
EO • EXPERIMENTAL GROUP/OWNER EW • EXPERIMENTAL GROUP/WORKER
CO • CONTROL GROUP/OWNER CW • CONTROL GROUP/WORKER
Figure 4.20. Protective Equipment Use by Observation Average of Summed Scores for Owners and Workers 112
7r------.
6
5
4 SCORE 3
2
o KNR KNM KNS ATR ATM ATS PRA PRM PRS aSR ass
_EO _EW Dca .cw
KNR = Knowledge-Pre-Test, KNM = Knowledge-Mid-Test, KNS = Knowledge-Post-Test
ATR = Attitude-Pre-Test, ATM = Attitude-Mid-Test, ATS = Attitude-Post-Test
PAR = Practice-Pre-Test, PAM = Practice-Mid-Test, PAS = Practice-Post-Test
OBR = Observation-Pre-Test, OBS = Observation-Post-Test
Figure 4.21. Comparison of Experimental and Control Groups of the Scores in Knowledge, Attitudes, Practices, and Observation in the Pre-Test, Mid-Test, and Post-Test 113 and practice scores on the mid-test and post-test being higher than pre-test scores, but the attitude scores for both owners and workers were almost the same level for the pre-, mid-, and post-tests. The respondents in both the owners' and workers' experimental and control groups show a pattern of change on the pre- and post-tests in that the health and safety training either improved or changed the behaviors observed on the post-test in terms of using protective equipment. In this chapter, the research findings, including socia-demographic characteristics of the sample, as well as knowledge, attitudes, and practices related to actual behavior regarding pesticide application, have been presented, along with findings concerning the results of the blood cholinesterase testing. The next chapter focuses on the details of chi-square analysis and discriminant analysis. 114
CHAPTER V ANALYSIS II
In this chapter, the balance of the research findings are presented in the next several sections, each of which has as its focus a specific type of data analysis. Each section reports the related general analytic information as well as more specific findings. The chapter begins with a discussion of the chi-square analyses which were used to examine the relationships among the independent variables (knowledge in using pesticides, attitudes towards using pesticides, past behavior in using pesticides, and also health and safety training) and dependent variables (behavior in using pesticides by observation of actual behaviors and blood cholinesterase activity in fresh blood by the Cholinesterase B method). Due to the large number of variables being examined, it is important to clarify the processes employed for variable reduction and presentation. As the first step, all variables were descriptively reviewed. This method was used to get a better understanding of the whole picture of the findings. Then, chi-square analysis was used to isolate relationships among a number of important variables. Chi-square analysis was found to be appropriate since most of our variables were categorical. As an attempt to determine the results of using Pearson Correlation as the measure of association between these variables a matrix of correlations (r) was created. Of the 28 possible correlations 14 were statistically significant. Eleven of 115 the 28 were statistically significant if chi-square is used. The overlap (significant on both) is 78% (11 of 14). Thus, chi-square was used. The probability threshold used to define statistical significance was P < .05. These relationships of interest were chosen to provide an initial assessment of the hypotheses of the study. In the second part, discriminant function analyses were employed to give a final quantitative multivariate interpretation of our hypotheses. Figure 5.1 shows statistically significant relationships among the five variables used to define socio-demographic characteristics of the population. The variables used have been operationally defined elsewhere and are named as Age, Sex, Marital Status, Education Level, and Status (Owner or Worker). Of the ten possible paired associations, seven had chi-square results that were statistically significant
(P < 0.05): Marital Status and Age, Marital Status and Sex, Education and Age, Education and Marital Status, Status and Age, Status and Marital Status, Status and Education. Figure 5.2 shows the extent to which the relationships between pairs of 15 knowledge variables were statistically significant in their associations. The variables used in the analyses were the wearing of long pants, long-sleeved shirts, boots, mask, and gloves in the pre-test, mid-test, and post-test. Of interest are the relationships between pre-, mid-, and post-test knowledge of the use of various protective apparel. In total, of the 120 possible relationships, only
seven were statistically reliable (P < .05). In Figure 5.3, knowledge of the use of specific protective equipment is associated with the respondents' summary knowledge of 116
1 2 3 S S 4 S S 5 S S S 1 2 3 4 5
S = Statistically Significant (P < 0.05) 1 = Age 2 = Sex 3 = Marital Status 4 = Education 5 = Status (Owner and Worker) Figure 5.1. Chi-Square Analyses Results for Socio demographic Variables 117
s- - - - s - - - s s
s -
1 2 3 4 5 6 7 8 9 10 11 12 13 14
S = Statistically Significant (P < 0.05) Long Pants 1 = Pre-test, 2 = Mid-test, 3 = Post-test Long-sleeved Shirts 4 = Pre-test, 5 = Mid-test, 6 = Post-test Shoes (Boots) 7 = Pre-test, 8 = Mid-test, 9 = Post-test Mask 10 = Pre-test, 11 = Mid-test, 12 = Post-test Gloves 13 = Pre-test, 14 = Mid-test, 15 = Post-test
Figure 5.2. Chi-Square Analyses Results for Knowledge Variables for Pre-, Mid-, and Post-tests 118
1 B o 0 2 0 B 0 3 B 0 0 4 - 0 W - 6 B B 6 - B 0 7 B B 0 8 - B B B 9 B 0 0 10 - B
11 B 0 0 0 12 - 0 B 13 B 14 - B KNR KNS ATR ATS PAR· PAS OBSR OBSS
Statistically Significant CP < 0.05) B = Both Owner and Worker o = Owner W= Worker Knowledge: Long Pants 1 = Pre-test, 2 = Post-test Long-sleeved Shirts 3 = Pre-test, 4 = Post-test Raincoat 5 = Pre-test, 6 = Post-test
Figure 5.3. Ch1-Square Analyses Results for Owners and Workers of Positive Responses for Individual Items on Knowledge Pre- and Post-tests by Overall Positie Responses on All Tests 119 protective equipment. Of the possible 112 associations, 17 were statistically reliable for both owners and workers. Fifteen were statistically significant for owners only and only one association was statistically significant for workers only. In general, it appears that knowledge of the use of specific protective equipment is only occasionally associated with the summative measure of pre-test knowledge. This suggests that the detailed method of assessment of knowledge used in this study was necessary in order to achieve a complete understanding of the participants' knowledge of protective equipment use. Figure 5.4 shows the extent to which the relationship between pairs of 15 attitude variables were statistically significant in their associations. The variables used in the analyses were the wearing of a hat, long pants, long-sleeved shirts, boots, mask, and gloves in the pre-test, mid-test, and post-test. Of interest are the relation ships between pre-, mid-, and post-tests attitudes toward the use of various protective apparel. In total, of the 120 possible relation ships, only eight were statistically reliable (P < .05). In Figure 5.5, attitudes towards the use of specific protective equipment are associated with the respondents' summary attitudes toward protective equipment. Of the possible 80 associations, ten were statistically reliable for both owners and workers. Twelve were statistically significant for owners only and there were none statistically significant for workers only. In general, it appears that pre-test attitudes toward the use of specific protective equipment are only occasionally associated with the summative measure of pre-test 120
1 _ 2 - 3 S - 4 5 6 - - -s 7 - - -- - 8 - - -- - 9 - - -s 10 - - 11 - - S 12 - - S 13 - - --- 14 ------15 ------1 2 3 4 5 6 7 8 9 10 11 12
S = Statistically Significant (P < 0.05) Hat 1 = Pre-test, 2 = Mid-test, 3 = Post-test Mask 4 = Pre-test, 5 = Mid-test, 6 =Post-test Gloves 7 = Pre-test, 8 = Mid-test, 9 = Post-test Clothes 10 = Pre-test, 11 = Mid-test, 12 = Post-test Boots 13 = Pre-test, 14 = Mid-test, 15 = Post-test
Figure 5.4. Chi-Square Anaiyses Results for Attitudes Variables for Pre-, Mid-, and post-tests 121
1 0 - 0 - - 0 - B 0 - - B 0 - B - 0 - - 0 - B B - B - 0 - - 0 - 0 B - B - 0 - 1 - 0 - B - B KNR KNS ATR ATS PAR PAS OBSR OBSS
Statistically Significant CP < 0.05) B = Both Ownwer and Worker. o = Owner W= Worker Attitude Hat 1 = Pre-test, 2 = Post-test Mask 3 = Pre-test, 4 = Post~test Gloves 5 = Pre-test, 6 = Post-test Clothes 7 = Pre-test, 8 = Post-test Boots 9 = Pre-test, 10 = Post-test Knowledge: Pre-test = KNR, Post-test = KNS Attitude: Pre-test = ATR, Post-test = ATS Practice Pre-test = PAR, Post-test = PAS Observation: Pre-test =OBSR, Post-test =OBSS
Figure 5.5. Chi-Square Analyses Results for Owners and Workers of Positive Responses for Individual Items on Attitudes Pre- and Post-tests by Overall Positive Responses on All Tests 122 attitudes and post-test attitudes toward using protective equipment. This also suggests that the detailed method of assessment of attitudes used in this study was necessary in order to achieve a complete under standing of the participants' attitudes toward protective equipment. Figure 5.6 shows the extent to which the relationships between pairs of 12 practice variables were statistically significant in their associations. The variables used in the analyses were the wearing of long pants, long-sleeved shirts, boots, and others such as gloves, mask, and hat in the pre-test, mid-test, and post-test. Of interest are the relationships between pre-, mid-, and post-tests practices in the use of various protective apparel. In total, of the 72 possible relationships, only eight were statistically reliable (P < .05). In Figure 5.7, practices in the use of specific protective equipment are associated with the respondent's summary practices in protective equipment. Of the possible 64 associations, six were statistically reliable for both owners and workers. Thirteen were statistically significant for owners only and two associations were statistically significant for workers only. In general, it appears that pre-test practices in the use of specific protective equipment are only occasionally associated with the summative measure of pre-test practices and post-test practices in using protective equipment. Figure 5.8 shows the extent to which the relationships between pairs of 16 behavioral observation variables were statistically significant in their associations. The variables used in the analyses were the wearing of a hat, mask, gloves (mix), gloves (spray), raincoat, long-sleeved s~rts, long pants and boots in the pre-test, mid-test, 123
1 2 S 3 S 4 5 6 7 8 s 9 s 10 - - - 11 - - - 12 - -- - s 1 2 3 4 5 6 7 8 9 10 11
S = Statistically Significant (P < 0.05) Long Pants 1 = Pre-test, 2 = Mid-test, 3 = Post-test Long-sleeved Shirts 4 = Pre-test, 5 = Mid-test, 6 = Post-test Shoes (Boots) 7 = Pre-test, 8 = Mid-test, 9 = Post-test Other Equipment 10 = Pre-test, 11 = Mid-test, 12 = Post-test
Figure 5.6. Chi-Square Analyses Results for Practices Variables for Pre-, Mid-, and Post-tests 124
1 B 0 0 2 - 0 B 3 0 0 0 W 4 - 0 0 B 5 0 B 6 - 0 7 B 0 0 8 - 0 B W
KNR KNS ATR ATS PAR PAS OBSR OBSS
Statistically Significant (P < 0.05) B = Both Owner and Worker o = Owner W= Worker Practice: Long Pants 1 = Pre-test, 2 = Post-test Long-sleeved Shirts 3 = Pre-test, 4 = Post-test Boots 5 = Pre-test, 6 = Post-test Other Equipment 7 = Pre-test, 8 = Post-test
Knowledge: Pre-test = KNR, Post-test = KNS Attitude: Pre-test = ATR, Post-test = ATS Practice: Pre-test = PAR, Post-test = PAS Observation: Pre-test =OBSR, Post-test =OBSS
Figure 5.7. Chi-Square Analyses Results for Owners and Workers of Positive Responses for Individual Items on Practices Pre- and Post-tests by Overall Positive Responses on All Tests 125
1 - 2 3 -s - 4 s- 5 6 s- S 7 s- S -s 8 9 - 8- 10 11 -s - - 8 - 12 S -8 - 8 13 -8 - 8- 8 - - 8 14 15 - 8- 8 - 16
S = Statistically Significant (P < 0.05) 1 = Pre-test, 2 = Post-test Hat 3 = Pre-test, 4 = Post-test Mask 5 = Pre-test, 6 = Post-test Gloves (Mix) 7 = Pre-test, 8 = Post-test Gloves (Spray) 9 = Pre-test, 10 = Post-test Raincoat 11 = Pre-test, 12 = Post-test Long-sleeved Shirts 13 = Pre-test, 14 = Post-test Long Pants 15 Pre-test, 16 Post-test Boots = =
Figure 5.8. Chi-Square Analyses Results for Behavioral Observation Variables for Pre-, Mid-, and Post-tests 126 and post-test. Of interest are the relationships between pre-, mid-, and post-tests behavioral observations of the use of various protective apparel. In total, of the 128 possible relationships, only 24 were statistically reliable (P < .05). In Figure 5.9, behavioral observation of the use of specific protective equipment is associated with summary observations of the respondents' use of protective equipment. Of the possible 128 associations, five were statistically reliable for both owners and workers. Thirteen were statistically significant for owners only and two associations were statistically significant for workers only. In general, it appears that pre-test observations of the use of specific protective equipment are only occasionally associated with the summative measure of pre-test observations and post-test observa tions of using protective equipment. This again suggests that perhaps the detailed method of recording observations of actual use of protective equipment employed in this study was necesssary in order to achieve a complete understanding of the participants' actual use. Figure 5.10 shows the extent to which the relationships between pairs of a total of knowledge, attitude, practice, and behavioral observation variables were statistically significant in their associations in the pre-test and post-test. Of interest are the relationships between pre-test and post-test in the other groups: knowledge and practices, knowledge and behavioral observation in the pre-test, knowledge and attitudes, attitudes and practices in both pre- and post-tests. In total, of the 32 possible relationships, ten were statistically reliable (P < .05). 127
1 - 2 - 0 3 - B 4 - B 5 - 6 - 0 7 - 0 B 8 - B 9 - 0 10 - B 11 W W 12 - 0 0 13 - 0 14 - 0 15 0 0 16 0-
Statistically Significant (P < .05) B = Both Owner and Worker o = Owner W= Worker Practice Long Pants 1 = Pre-test, 2 = Post-test Long-sleeved Shirts 3 = Pre-test, 4 = Post-test Boots 5 = Pre-test, 6 = Post-test Other Equipment 7 = Pre-test, 8 = Post-test Knowledge: Pre-test = KNR, Post-test = KNS Attitude: Pre-test = ATR, Post-test = ATS Practice: Pre-test = PAR, Post-test = PAS Observation: Pre-test =OBSR, Post-test =OBSS Figure 5.9. Chi-Square Analyses Results for Owners and Workers of Positive Responses for Individual Items on Behavioral Observations Pre- and Post-tests by Overall Positive Responses on All Tests 128
1 - 2 3 4 - SS 5 S - S 6 - S 7 S 8 - 1 2 3 4 5 6
S = Statistically Significant (P < 0.05)
Knowledge: Pre-test = 1, Post-test = 2 Attitude: Pre-test = 3, Post-test = 4 Practice: Pre-test = 5, Post-test = 6 Observation: Pre-test = 7, Post-test = 8
Figure 5.10. Chi-Square Analyses Results for Knowledge, Attitudes, Practices and Behavioral Observation Variables for Pre-test and Post-tests 129 We found that the relationship between each of the total scores on knowledge, attitudes, practices and behavioral observation in using each kind of protective equipment was better than results across these variables for each kind of protective equipment.
Discriminant Function Analyses
In this section, results of the discriminant function analyses are presented. Discriminant function analysis was used to identify factors that might predict the knowledge, attitude, practice and observation levels in using protective equipment. All variables that were significantly associated in the chi-square analyses were chosen for this analysis. In the discriminant function analyses, two criteria of patterns of using protective equipment were examined. They were: (1) the criteria that indicate which groups (experimental or control) seek unsafe acts in terms of knowledge, attitude, practice and behavioral observation scores after receiving health training compared to the data before training and (2) the criteria that indicate which groups were associated with blood cholinesterase activity. Since there were a number of suspected discriminating variables, unnecessary variables were eliminated using a stepwise inclusion procedure. The Wilks Method Discriminant function analysis is a step wise analysis based on minimizing the overall Wilks' Lambda (Norusis, 1985); thus, the variables that minimized overall Wilks· Lambda were selected. 130 Two separate discriminant analyses were run: first, with patterns as the independent variable and general demographics, and, second, with dependent variables.
Discriminant Function Variables
Eighteen potential variables were analyzed in the stepwise discriminant function in order to discover the predictor variables that would maximally discriminate between people who used protective equipment and those who did not. The eight explanatory variables were: 1. KNPRE KNOWLEDGE PRE-TEST 2. KNPOS KNOWLEDGE POST-TEST 3. ATPRE ATTITUDE PRE-TEST 4. ATPOS ATTITUDE POST-TEST 5. PRPRE PRACTICE PRE-TEST 6. PRPOS PRACTICE POST-TEST 7. OPRPRE OBSERVATION PRE-TEST 8. OPRPOS OBSERVATION POST-TEST and the ten dependent categorized discriminant function variables were: 1. CP12 MASK (POST-TEST) 2. CB13 GLOVES ON MIXING (PRE-TEST) 3. CB14 GLOVES ON SPRAYING (PRE-TEST) 4. CP14 GLOVES ON SPRAYING (POST-TEST) 5. CP15 RAINCOAT (POST-TEST) 6. CP16 SHIRT (POST-TEST) 7. CBl7 PANTS (PRE-TEST) 8. CP17 PANTS (POST-TEST) 9. CP18 BOOTS (POST-TEST) 10. CP41 CHOLINESTERASE (POST-TEST-BEFORE SPRAYING)
Because a stepwise procedure was used to derive the following discriminant function analyses, in addition to variables in predictive efficiency, variation in the discriminating factors should be expected. As a result, a separate analysis will be presented for each piece of protective equipment as well as for the summary variables. Figure 5.11 represents the combined distribution of the scores in using a mask in post-test for two groups, and it can be seen that Canonical Discriminant FuncLion 1 200 + +
F 2 l' 150 + 2 + e 2 q 2 u 2 e 100 + 2 + I n I 2 I o I 222 I y I 2 2 2 50 + 1 2 2 + 122 1 2 1 2 1112122 2 x------+------+------+------+------+------x OuL -4.0 -2.0 0.0 2.0 4.0 Out Clam~ 1111111111111111111111111111122222222222222222222222222222222 Cenlroidl:l 1 2
Figure 5.11. All-groups Stack Histogram Canonical Discriminant Function 1 in Using a Mask in Post-test -' w -' 132 there is overlap between the categ9ries of the predicted variable (use of mask). In this figure a typical discriminant function predictant is presented. The figure is a graphical representation of the extent to which the subcategories of the variables of interest (use of mask) are categorized by the array of predictor variables (observation-post test and practice-post-test). Table 5.1 shows that in total, 89% of the cases were correctly classified by those mask (post-test) variables. In fact, for affirmative responses, the predictor variables improved prediction by 43.5% over what could be expected by chance alone (50%). With respect to the appropriate use of a mask, the summary measure of all protective equipment use variable at the observation post-test and practice test was the most powerful predictor. This suggests that we found the total scores of observation post-test and the practice post-test were the best improved use in mask. When the observers walked through survey in the post-test, they found the sprayers using the mask.
Table 5.1 Percentage Breakdowns of Discriminant Function for Using a Mask (Post-test)
No. of Predicted Group Membership Actual Group Cases o (No) 1 (Yes)
Group o (No) 99 75 24 75.8% 24.2% Group 1 (Yes) 292 19 273 6.5% 93.5% Percent of "grouped" cases correctly classified: 89.00% 133 Figure 5.12 represents the combined distribution of the scores for each subcategory of the variable of interest (use of gloves). It can be seen that there is overlap between the subclasses. In this figure a typical discriminant function predictant is again presented. The figure is a graphical representation of the extent to which the subcategories of the variables of interest (use of gloves on spraying) are categorized by the array of predictor variables: observation (post-test), knowledge (post-test) and practices (post-test). Table 5.2 shows that nearly 91% of the cases were correctly classified by those gloves on spraying variables in the post-test group. In fact, for affirmative responses, the predictor variables improved prediction by 42.0% over what could be expected by chance alone. The use of those gloves on spraying was best predicted by the knowledge post-test and practice post-test. This suggests that after the participants got training, they had a clear idea about the use of gloves and protected themselves when they sprayed pesticides. The results for the post-test shows an improvement in glove use over the pre-test. The participants must have accepted the idea of protecting themselves by using gloves when spraying pesticides in their fields. Figure 5.13 represents the combined distribution of the scores for the two subgroups of the variables "long-sleeved shirts" use, and it can be seen that there is overlap between the subgroups. In this figure the typical discriminant function predictant is presented. The figure is a graphical representation of the extent to which the subcategories of the variables of interest (use of long-sleeved shirts) Canoni6al Discriminant Function 1 200 + 1 + 1 1 F 1 l' 150 + 1 + I e 1 2 I I q 1 1 I I u 1 1 I e 100 + 1 1 + n 1 1 o 1 1 y 1 11 50 + 1 11 + 11 11 11 11 I 1 1111 11 22 2 I Outx------+------+------+------+------+------x-4.0 -2.0 0.0 2.0 4.0 Out ClasM 1111111111111111111111111111111111111222222222222222222222222 Centroids 1 2
Figure 5.12. Canonical Discriminant Function 1 in Using Gloves on Spraying in Post-test
~ w ~ 135 are categorized by the array of predictor variables: observation (post-test) and knowledge (post-test).
Table 5.2 Percentage Breakdowns of Discriminant Function for Using Gloves on Spraying (Post-test)
No. of Predicted Group Membership Actual Group Cases 0 1
Group 0 303 273 30 90.1% 9.9% Group 1 88 7 81 8.0% 92.0% Percent of "grouped" cases correctly classified: 90.54%
Table 5.3 shows that 81% of the cases were correctly classified by those long-sleeved shirts variables in the post-test. In fact, for affirmative responses, the predictor variables improved prediction by 30.7% over what could be expcected by chance alone. The use of long-sleeved shirts was best predicted by the observation post-test and knowledge post-test. It seems to be that they came to understand that using long-sleeved shirts helped protect their skin from contact with pesticide fumes. Figure 5.14 represents the combined distribution of the scores for two groups, and it can be seen that there is overlap between the subgroups. In this figure a typical discriminant function predictant is presented. The figure is a graphical representation of the extent to which the subcategories of the variables of interest (use of a Canonical Discriminan~ Function 1 160 + +
F r 120 + + e: 1 q: 1 u: 1 2 e 80 + 1 1 + 11: 11 1 c: 11 1 y: 111 11 40 + 111 11 + 111 111 1111 1111 1 11111 11111 22 , Outx------+------+------+------+------+------x-4.0 -2.0 0.0 2.0 4.0 Out Clas~ 1111111111111111111111111111111111111222222222222222222222222 Centroids 1 2
Figure 5.13. Canonical Discriminant Function 1 in Using Long-sleeved Shirts in Post-test .... W 0\ 137 raincoat) are categorized by the array of predictor variables; observa tion (post-test) and practices (post-test).
Table 5.3 Percentage Breakdowns of Discriminant Function for Using a long-sleeved Shirt (Post-test)
No. of Predicted Group Membership Actual Group Cases o (No) 1 (Yes)
Group o (No) 29 23 6 79.3% 20.7% Group 1 (Yes) 362 70 292 19.3% 80.7%
Percent of "grouped ll cases correctly classified: 80.56%)
Table 5.4 shows that 75% of the cases were correctly classified by those raincoat variables in the post-test. In fact, for affirmative responses, the predictor variables improved prediction by 24.9% over what could be expected by chance alone. The use of a raincoat was best predicted by the observation post-test and practices post-test. This suggests that some might think that using a raincoat is not necessary for them, and also that the warm weather makes a raincoat inappropriate. Figure 5.15 represents the combined distribution of the scores for two groups of the vari ab1e "use of boots," and it can be seen that there is overlap between the subgroups. In this figure a typical discriminant function predictant is presented. The figure is a Canonical Di8criminan~ Function 1 160 + +
F t: 120 + + ~ i 1 q : 1 u : 1 ~ 80 + 1 + n : 1 c : 1 y: 1 1 1 2 40 + 1 1 1 2 + 111 2 1 1 1 12 2 2 1 1 11 1 11 1 12 2 I OuLx------+------+------+------+------+------x-4.0 -2.0 0.0 2.0 4.0 Out Class 1111111111111111111111111111111111222222222222222222222222222 CenLroids 1 2
Figure 5.14. Canonical Discriminant Function 1 in Using a Raincoat in Post-test ..... w OJ 139
Table 5.4 Percentage Breakdowns of Discriminant Function for Using a Raincoat (Post-test)
No. of Predicted Group Membership Actual Group Cases o (No) 1 (Yes)
Group 0 (NO) 28 22 6 78.6% 21.4% Group 1 (Yes) 363 91 272 25.1% 74.9% Percent of "grouped" cases correctly classified: 75.19%) graphical representation of the extent to which the subcategories of the variables of interest (use of boots) are categorized by the array of predictor variables: observation (post-test) and attitudes (post test) • Table 5.5 shows that only about 50% of the cases were correctly classified by those boots variables. In fact, for affirmative responses, the predictor variables improved prediction by 15% over what could be expected by chance alone. The use of boots was best predicted by the observation post-test and attitude post-test. This suggests that there were some who thought using boots was useless or uncomfortable. They were used to bare feet or slippers in previous practices when they walked in mud and dirt, and might have felt that it was inconvenient to wash boots after work in the field. However, they still improved their behavior in that after training, they used boots much more than before. Canonical Discriminant FuncLion 1 200 + +
F 2 l' 150 + 2 + I e I 2 I q I 2 I u I 2 e 100 + 2 + I I 11 I 2 I I I e I 222 I I I y I 222 I 50 + 222 + 222 22222 I 2 1 2 2 2 2 2 2 x------+------+------+------+------+------x Ou~ -4.0 -2.0 0.0 2.0 4.0 Out Clays 1111111111111111111111111111222222222222222222222222222222222 Cent.roids 1 2
Figure 5.15. Canonical Discriminant Function 1 in Using Boots in Post-test
~ ~ o 141
Table 5.5 Percentage Breakdowns of Discriminant Function for Using Boots (Post-test)
No. of Predicted Group Membership Actual Group Cases o (No) 1 (Yes)
Group o (No) 292 129 163 44.2% 55.8% Group 1 (Yes) 100 35 65 35.0% 65.0% Percent of "grouped" cases correctly classified: 49.49%
Figure 5.16 represents the combined distribution of the scores for the subgroups of the variable "use of long pants," and it can be seen that there is overlap between the subgroups. In this figure a typical discriminant function predictant is presented. The figure is a graphical representation of the extent to which the subcategories of the variables of interest (use of long pants) are categorized by the array of predictor variables: observation (post-test), practices (post-test) and attitudes (post-test). Table 5.6 shows that 74% of the cases were correctly classified by those pants (post-test) variables. In fact, for affirmative responses, the predictor variables improved prediction by 13.5% over what could be expected by chance alone. The use of long pants was best predicted by the observation post-test, attitude post-test and practice post-test. This suggests that there were some who thought using long pants was useless or uncomfortable. They were accustomed to using short pants in previous practices. They felt that long pants Canonical Discriminant Function 1 160 + +
F 2 r 120 + 2 + e 2 q 2 u 2 e 80 +, 2 + 11 , 222 c I 222 I y I 2 222 40 + 2 222 + 2 2 222 2 2 2 2 2 2 2 , 112 1 222 2 x------+------+------+------+------+------x Out -4.0 -2.0 0.0 2.0 4.0 Out Cla~8 1111111111111111111111111111222222222222222222222222222222222 CenLroids 1 2
Figure 5.16. Canonical Discriminant Function 1 in Using Long Pants in Post-test
..J ~ N 143 were properly for going out. Also they might be confused about which kind of long pants are appropriate for use in their fields.
Table 5.6 Percentage Breakdowns of Discriminant Function for Using Long Pants (Post-test)
No. of Predicted Group Membership Actual Group Cases 0 1
Group 0 328 248 80 75.6% 24.4% Group 63 23 40 36.5% 63.5% Percent of "grouped" cases correctly classified: 73.66%
Figure 5.17 represents the combined distribution of the scores for the cholinesterase variable. It can be seen that there is overlap between subgroupings. In this figure a typical discriminant function predictant is presented. In this figure we see a graphical representa tion of the extent to which the subcategories of the variables of interest (use of gloves, long pants, a mask in post-test) are categorized by the array of predictor variables from cholinesterase (post-test). From Table 5.7 we see that 70% of the cases were correctly classified by those cholinesterase (post-test) variables. In fact, for affirmative results, the predictor variables cholinesterase level improved prediction in less than normal by 23.7% over what could be expected by chance alone: the use of gloves on spraying, long pants, a mask, as shown in that level. This suggests that even with the use Canonical Discriminant Function 1 160 + 1 + 1 1 F 1 r 120 + 1 2 + e 1 2 q 1 2 u 1 1 e 80 + 1 1 + I n I 1 1 I o I 21 1 I y I 11 1 40 + 11 21 + 11 11 11 11 22 I 1 111111 111111 2 I X------+------+------+------+------+------X Out -4.0 -2.0 0.0 2.0 4.0 Out Chu~s 1111111111111111111111111111111111222222222222222222222222222 Centroids 1 2 -~-_._------
Figure 5.17. Canonical Discriminant Function 1 in Using Gloves, Long Pants, a Mask from Cholinesterase Level in Post-test -I .:: ~ 145 of protective equipment, there was still the danger of pesticide contact for the participants. Perhaps the equipment that they used was outdated or ineffective.
Table 5.7 Percentage Breakdowns of Discriminant Function for Cholinesterase (Post-test) and Using Gloves on Spraying, Long Pants, a Mask in Post-test
No. of Predicted Group Membership Actual Group Cases 1 «1140) 2 (1140-1590)
Group 156 115 41 <1140 73.7% 26.3% Group 2 30 15 15 1140-1590 50.0% 50.0% Ungrouped Cases 210 152 58 72.4% 27.6% Percentage of "grouped" cases correctly classified: 69.89%
Table 5.8 shows the summary of predictors of actual use of protective equipment in observation, practices, attitudes, knowledge in the post-test, and the cholinesterase level related to actual use of protective equipment. Generally, observation was the best predictor of actual behavior in using protective equipment and also the best measure of specific evidence for actual use. As for the practices, the respondents generally told in the questionnaires what they would use in the field, but they obviously changed their minds. People may not necessarily do what they say they will do. As for the attitudes, Table 5.8 Predictors of Actual Use of Protective Equipment in Knowledge, Attitudes, Practices and Observation and the Cholinesterase level
Predictor in Post-Test Actual Use Accuracy Observation Practice Attitude Knowledge Chol
Mask 89% X X X Pants 73% X XX X Gloves on Spraying 90% X X XX Boots 49% X X Shirts 80% X X Raincoat 75% X X
-' .Jlo m 147 the respondents may have a positive attitude toward the use of protective equipment, particularly boots and long pants, but the right attitudes did not lead them to do the right thing. As for the knowledge, it was not a good predictor of actual use, and therefore a new way to give orchid workers more knowledge and better attitudes should be tried. Notion the certain type of protective equipment seem to be more related to cholinesterase level than others. Specifically, the mask, gloves-on spraying and long pants are the best predictors. We suggest that appropriate protective equipment should be inexpensive, easy to carry around and of good quality to protect from the fumes of pesticides. Chi-square analysis was used to find an appropriate way to solve the problem as follows from the hypotheses and to determine which variables were categorical. In the second part, discriminant analyses helped to give a final quantitative interpretation of the hypotheses. The next chapter presents the results based on the findings and a discussion. 148
CHAPTER VI DISCUSSION AND CONCLUSION
This chapter presents a summary and discussion of study findings. Suggestions for the direction of future research and implications for strategies for influencing protective equipment use are presented. The results from the discriminant function analyses and Chi-square analyses demonstrate the intensity of the socio-demographic, knowledge, attitude and practice characteristic variables in influencing the use of protective equipment. These results will lead us either to accept or to reject the hypotheses of this study. Based on the findings and discussions we also propose a set of recommendations regarding health and safety program development and the improvement of training of respondents in future studies.
Interpretation of Chapters IV and V
The socio-demographic backgrounds of both experimental and control groups were homogeneous, but there were differences between owners and workers. The owners had a much higher educational level than the workers. During the health and safety training, detailed information was presented to the workers and the owners; pictures were used to teach the correct way to apply pesticides and use protective equipment. Although both groups received new knowledge, the owners had higher knowledge scores than the workers from the beginning. If the owners already had a good knowledge of how to use protective equipment, it 149 is questionable whether the training helped them to change their behavior or not. The owners' scores on questions of knowledge did not change significantly, which suggests that either they did not always trust the information or they spent some time thinking about it and finally accepted an answer as correct. This was reinforced in their high scores on the behavioral observations. The new knowledge acquired in this training program might not have been enough to change their practices in protective equipment use. The workers had a lower base score but appear to have remembered what we told them, even though they sometimes did not fully comprehend it. They believed that it was fact (similar to "rote Iearntnq," in which children learn their numbers by repetition and memorization), but this only made them remember, not necessarily understand. However, when we told them to learn this information, they had no idea what it was but felt sure that it must be good, and so they started to memorize what we taught. An industrial hygienist might see the point of "at r i sk" in the characteristics of sprayers between both the owner and worker that were different. The workers had more potential pesticide exposure than the owners because they had different skills in knowledge, attitudes and practices, and supported funds. In this situation, the workers are in a very dangerous position and need help quickly. These findings should be viewed from the perspective of their general meaning as well as their specific meaning for the training of these particular owners and workers. We should have a general interest in the retention of knowledge of the use of protective 150 equipment and adaptation to correct practices. Finally, the extent to which both groups integrated their new knowledge and readjusted their own ways to protect themselves should be of general interest. For these changes to occur, we believe they must have altered their attitudes if they came to accept what was taught to them. At this point we believe it is important to have a follow-up program offered and the government should arrange for a seminar supporting long-term behavioral change. The health and safety training designed for this research project can be applied to any training program involving pesticide applicators. After analyzing the results of this health training, modifications can be made in the design, which can serve as a model for future safety training for all people involved in applying pesticides. The Ministry of Health might be able to provide similar training programs throughout Thailand for all agricultural workers based on the results of this research. This research can also provide specific suggestions through which the Public Health Department at Mahidol University can design a course concerning PESTICIDE DANGERS IN THE ENVIRONMENT. In addition, we plan to recommend that Mahidol University provide a short training course in PROPER PESTICIDE USE for rural health workers so that everyone can become more aware of the dangers now present throughout Thailand. We could also try to convince the government that there is a need for a mobile team to provide pesticide safety training to villagers in all parts of Thailand. The most important goal of our project was to increase public and governmental awareness of the growing problem of widespread pesticide use and the dangers therein. 151 At present, the use of protective equipment among the agricultural workers of Thailand is known but what is not always clear is which type is effective for the job, even though widespread use of dangerous pesticides is constantly increasing. This research reveals some of the reasons why protective equipment is not being used. If poor attitudes are responsible, remedies for changing such attitudes can be proposed. The results of blood cholinesterase activity provide only an approximate measure of the cholinesterase level which is colorimetric but which does not me~sure the actual quantity of cholinesterase. If there has been a change in behavior, there may not be a change in the cholinesterase level of the blood. This is just another benchmark as to whether there had been continued exposure in one group; other measures were used as well. The blood results have shown that we cannot accurately determine the difference between pre-test and post-test exposure. 'However, we still benefited by learning that the Tinometric method and the Cholinesterase B method can be used in field studies in pesticide exposure since they give blood results immediately. Our results showed a depression of cholinesterase level that depended on the pesticide exposure of the sprayers who had accumulated a higher or lower concentration of pesticide fumes. It also depended on whether the sprayers' bodies could resist the exposure or not. For example, sprayers who spray in the same field might not have the same cholinesterase level. Some of them might show a decrease in cholinesterase level immediately, but others might show an increase over normal cholinesterase level which is revealed through other 152 diseases such as diabetes mellitus, cirrhosis, acute hepatitis, etc. While analyzing the blood cholinesterase level, we screened for other enzymes such as SGPT (SERUM-GLUTAMIC-PYRUVIC-TRANSMINASE), tested for hepatic tissue damage, and did SGOT (SERUM-GLUMATIC-OXALOACETIC TRANSAMINASE), testing for liver disease or severe heart problems. We did not find any cases of these diseases, and also less than 10% of the samples showed an above normal cholinesterase level in the pre test and the post-test. This may have been due to an innate bodily resistance against pesticides. A few sprayers who showed a normal level of cholinesterase in the post-test before spraying showed an upswing in the level after they were exposed to the pesticide fumes. We learned that the results of the blood cholinesterase in the sprayers, especially the workers, are lower than the normal level meaning that they had had potential pesticide exposures. Also, we found that these low levels of cholinesterase were associated with the protective equipment use: a mask, gloves on spraying and long pants. We learned from the results that even though they try to use protective equipment, they still had low levels of the cholinesterase meaning that the effectiveness of the equipment was low. When more people use the protective equipment, they will try to continue in using more items of protective equipment.
Results of Hypotheses Testing
The overall assumption of this study is that people seek and comply with health-care regimens (preventive regimens such as health screening, or rehabilitative regimens such as treatment for a diagnosed disease) only under certain specific conditions. We applied this 153 assumption to the use of protective equipment, and in safety conditions in pesticide usage. We believe that people must possess some minimal level of health knowledge and motivation towards good health. They must also come to believe that they are vulnerable to a threatening illness condition. They must be convinced that treatment can be efficacious (i.e., that it is indeed possible to obtain control over the disease), and that the cost of such control is not high in view of the benefits. In essence, this is what has been described as the Health Belief Model (Rosenstock, 1974). As we now specify this model to the circumstances surrounding pesticide applications in Thailand, we will begin to examine our series of subhypotheses. First hypothesis (Development of knowledge): The behavior of sprayers who have received health and safety training will be more positively affected than those who did not receive such training. Chi-square analysis of the data supported this hypothesis. The behavior of sprayers in the experimental group changed much more than in the control group. The results supported the hypothesis and were significant statistically (Chi-square value of 36.7522, df 12, P-value 0.0002). Second hypothesis (Knowledge-Attitude-Practice relationship): Individuals who have greater knowledge, better attitudes, and better practices in using pesticides will use protective equipment more often than other groups. Discriminant function analyses supported the notion that individuals who have greater knowledge, better attitudes, and better 154 practices in using pesticides will use protective equipment more often than other individuals. The results showed an improvement in the patterns of use of protective equipment. Observed improvements in use of different types of protective equipment--masks, gloves for mixing, gloves for spraying and long-sleeved shirts, and long pants- are shown in Figure 6.1. This suggests that knowledge, attitude and practice in one area may influence behavior in a related area. A comparison of the results of both pre-test and post-test shows improved behavior after the owners and workers had the health training for four items: shirt, maks, gloves-on spraying, and gloves-on mixing. However, there was a major decrease in the proper use of boots and slight decrease in the proper use of long pants. It seems that some of the participants were confused about using boots because they were not used to wearing them. Furthermore, they had many reasons for not using boots, such as they made it difficult to walk in the fields. Similarly, there was confusion about the proper use of long pants. Third hypothesis (Susceptibility and Vulnerability): Individuals who believe they are susceptible to the harmful effects of pesticides are more likely to use protective equipment than individuals who do not believe they are susceptible to such effects. Chi-square analysis suggested that the results were all statis tically non-significant, that the relationship is a weak one in this sample. Fourth hypothesis (Effectiveness of Equipment): Individuals who use protective equipment have much better results regarding blood cholinesterase level than those who do not use protective equipment. 155
50.------,
40
30
.. 20
SHIRT PANTS GLO. M. GLO. S. MASK BOOTS
_ PRE-TEST _ POST-TEST
Figure 6.1. Observed Improvements in the Use of Specific Protective Equipment 156 Chi-square analysis supported the hypothesis. Individuals who use protective equipment such as mask, long pants and gloves-on spraying have much better results regarding blood cholinesterase level than those who do not use protective equipment in both the experimental group and the control group. The results confirmed the hypothesis and were significant statistically (Chi-square value of 25.0309, df 8, P-va1ue 0.0015). Fifth hypothesis (Know1edge-Attitude-Protection linkage): Individuals who have greater knowledge and appropriate attitudes towards using pesticides will have better results of cholinesterase than other groups which have less knowledge and inappropriate attitudes. Chi-square analysis for the samples suggests that the results were all statistically non-significant. However, the results of the blood samples in the group that had been continuously exposed to pesticide for at least three hours showed a lower level of cholinesterase activity. In addition, mild and moderate toxicity symptoms of pesticide poisoning were found in this group. The health and safety training helped the experimental group to improve their knowledge regarding pesticides and to have better practices in using protective equipment. With their new knowledge, they remembered to wear a long-sleeved shirt and long pants when spraying pesticide but they were still not comfortable wearing boots. In this research, the best ways of using protective equipment and correctly applying pesticides in their fields were provided to the members of the experimental group. It was difficult for those 157 who have never used protective equipment from the start. They had many reasons for not using protective equipment, such as the hot weather, and the problems of incorrect size, expense, and perceived ineffectiveness of the protective equipment. Finally, they have a need to learn how to use protective equipment and know about the toxicology of pesticides. They need to open their minds and be more aware when applying pesticides and this may require a massive education program and a much wider scientific literacy before acceptance.
Limitations of the Study
It has often been observed that people generally conform to what is expected of them by people in positions of authority. Thai workers sometimes did not give sincere responses to questions concering their behavior in applying pesticides but instead answered in such a way as to please the researcher. This was so even though we attempted to solve the problem by focusing instead on the relationship between attitudes and actual behavior. One example on the attitude questions was when respondents trying to be cooperative would choose "uncertain, II even if they may have wanted to answer II agree II or "disagree." Another example involved alcoholic beverage and smoking habits where non-smoking and non-drinking were shown to have unusually high percentages. Field observations also gave misleading results if the workers were able to prepare for the visit of the research staff. To counter this, the agricultural officers made their observations on a random schedule without notifying the farmers. If the results were incon clusive, they would request a second observation for verification of 158 the data. Most of the observers did a very good job at the pre-test, but they did not realize that the post-test was equally as important. The results at the post-test were not as good. There were a lot of problems in finding individuals in both experimental and control groups willing to join the health and safety training course. For example, just one day before the health training started, it rained very hard and flooded the nurseries. We were con cerned that some farmers would not be able to come to the center by themselves, so we arranged for a mini-bus to deliver them to the center. Also, some of the individuals declined to join this course because they had to deal with export companies who had ordered flowers for immediate delivery. In the end, only 80 members of the experimental group participated, in the health and safety training, and this included a high proportion of owners. Although we were disappointed with the turnout, we felt that this number was still adequate for our purposes. In addition, there was more interest shown by the experimental group than in the control group because of the subject matter of their respective training. Some trainers reported that the people in the control group seemed bored, because they felt they were learning nothing new, while the experimental group believed they were receiving new information on health and safety. There may have been different results if the members of the two groups had traded places. In terms of blood testing, there was a problem in that both the Tintometric method and the Cholinesterase B method were used in the pre-test, but in the post-test only the Cholinesterase B method was 159 used. This was because the Shell Oil Company offered to participate only in the pre-test. However, the differences in results between the two methods used in the pre-test were non-significant. Thus, our post-test results would appear valid. We had hoped to focus on the respondents who sprayed and applied specific pesticides in the orchid nursery fields. In actual practice, however, many chemicals are mixed together to deal with various pests. It is probably impossible to measure exposure to only one or two particular formulations even if a laboratory is used for analysis. Some owners who did not spray frequently and whose results were normal in the pre-test requested to know whether their blood results were safe or not. In the post-test, we wanted to test only the workers who were actual sprayers. We wanted to know the differences in the results before spraying and after spraying, and so we wanted to take blood samples just before spraying and three hours after. However, we encountered two problems. First, people did not want to have blood drawn before spraying, because they felt that the pre-test blood drawing had been enough. Secondly, at the time of blood collection there was rain and some subjects, who had their blood drawn before spraying, cancelled their spraying and did not want to have blood drawn afterward. For this reason, not every participant gave three separate blood samples. Comparisons are therefore difficult, because there were less than 100 people who (1) completed the health and safety training and (2) gave all of the required blood samples. 160 Suggestions for Further Research
If this type of study is to be attempted again, it may be advisable to conduct the health and safety training program with the owners and the workers in different groups, or to include only the owners or only the workers in the study. Because of the differences in socio demographic background, it is difficult to approach owners and workers in the same way. The next questionnaire might include questions that would allow the participants to express their opinions about using protective equipment and to tell about when they used protective equipment for the first time. On the other hand, because of the problems in the current study of people saying that they were going to do things which they never did, and answering the questionnaire trying to please the interviewer, observations might be made a more important part of the next study. However, it will be very important to properly train the people who will do the observing. In the current study, there was a problem in getting the recruited agricultural officials to follow the experimental design. They did not understand how to collect data carefully or recognize the importance of following the same procedures with each data collection. Further, considerable time must be devoted to observations. In the current study, the respondents would sometimes use protective equipment during the time of the observations, and once the observer left for a while they would give up using it. The period of observation should be stretched over an entire year, and the respondents should not be informed of the schedule for observing them. 161 Another problem of the current study that should be overcome is that the respondents often felt tired of the training. When they heard the word IItraining,1I they would feel like a student again and want to escape. This was because the government has been trying to train the villagers and they had had too many courses before this study started. The next study might try to approach the respondents in different ways, such as using pamphlets, movies, or television or radio programs, and let them receive their knowledge gradually. It might be a good idea to recode a radio program, let the respondents listen to it, and have them discuss some of the ideas of the program in small groups. Their reactions in the groups could be observed. At the end of training, they could practice the use of protective equipment. Indeed, considerable thought must be given to the type of training program which will lead to lasting behavioral change. People, when they want to change their behavior, should not feel like they should do so only under supervision, or acquiesce to a symbolic acceptance. They should want to adopt the new behavior, to the point of effective ness. They may study how to use protective equipment and then believe that they are doing enough if they do small things correctly 10% of the time. This situation is very dangerous because they may become stubborn and not open their minds to the fact that their behavior remains very dangerous. If they try to use one, two or three kinds of protective equipment, that is good for a start; they can take time to understand more and finally adopt the behavior 100% of the time. 162 Conclusion
At present, one of the major problems in most countries is the lack of a definitive government policy for the provision of occupational health services. Both industrial and agricultural workers have problems in working with toxic substances. With the prevalence of chronic diseases from incorrect pesticide application and in the absence of medical screening, workers in developing countries are at extreme risk for aggravating general health problems due to inadequately controlled occupational hazards. This is an important feature of developing countries and requires a special approach. For this reason of exposure, environmental pollution is of global concern. The health problems associated with workers exposed to pesticide fumes need our critical attention. The health hazards of such agents have been inadequately investigated and there is a need for such work. It is important to consider these data in relation to the traditionally accepted health problems of the majority of agricultural nations of the developing world. It would be agreed that, by any standard, the subject of pesticide poisoning assumes an important position in an agricultural country such as Thailand, a position which is likely to be held in other agricultural nations of the region. In areas where farming is carried out at subsistence levels and in small industries, rural and suburban health services belonging to government should institute preventive measures. In addition to primary care, these services should be prepared to deal with the prevention of specific occupational health problems, such as toxicity 163 of pesticides, respiratory diseases due to various dusts, and occupational accidents. When there are critical health problems in the community, the government should set up a committee to solve these problems. For example, Hawaii currently has a problem in controlling the use of pesticides. Several different government agencies are responsible for regulating pesticide use and presently these agencies are not we11 coordinated and have overlapping responsibilities. There is no doubt that legislation is necessary, provided there is a reasonably effective machinery for implementing it. Nevertheless, experience has shown that it cannot be the only, or even the major, means by which governments try to achieve objectives. There are essential components in human nature and behavior. Conscience, understanding and cooperation help in the assessment of needs and the creation and development of effective health services where organizations are capable of estab lishing them on their own. Such a sense of responsibility for the health and safety of workers can be stimulated by education and training, and by demonstrating the economic value of a healthy work force. It is undoubtedly as important as, or even more important then, legislation and enforcement, and more lasting and effective. Governments have an obligation to ensure the safety and health of workers. This invariably creates problems of delineating areas of responsibility, powers of entry and enforcement, and coordination, both locally and with international agencies. lack of a definite policy base or distribution of activities leads to problems in legislation. However, it is difficult to decide whether the policy basis leads to 164 the provision of legislation or vice versa. Legislation is first enacted by the Ministries concerned so as to involve a policy basis for the establishment of occupational health services. Legislation in occupational health and safety is necessary in developing countries. Account should be taken of past experience and of specific national priorities. Legislation should be comprehensive. The responsibilities and functions of government bodies, management and labor should be clearly defined and emphasis should be laid on coordination. Legislation is of limited usefulness in the absence of an adequate and well-equipped administrative body, and it is essential to give special attention to enforcement. This leads to insufficient or inadequate implementation of legislative requirements and usually leads to ineffective enforcement of laws. In Thailand, legislation is outdated, inadequate or vague in powers of enforcement, and in revision and updating. Overcoming this problem will depend on the system of government or parliamentary procedure, by having enabling legislation to formulate regulations from time to time without the need to pass through lengthy parliamentary procedures or government decree. This will not be an easy task for a country like Thailand. At the present time it would be quite difficult for the government to effectively regulate the powerful international companies involved in the production and distribution of pesticides which are in great demand. Instead the government should focus on the comprehensive training of the pesticide applicators in the correct use of protective equipment. 165 There is also a need for the provision of statutory regulations and Codes of Practice, especially for the use of highly toxic substances and the control of high-risk occupations. These regulations should include exposure limits, both threshold values and maximum permissible limits, with specific medical or health-based surveillance programs, including safety standards and procedures. The regulations should also restrict the importation of particularly dangerous pesticides. Health and safety is a significant problem in any country. There is insufficient information on the magnitude of the health problems affecting workers in different occupational sectors and particularly the underserved working population. Some of the areas where such vital information is lacking is in relation to the incidence and prevalence of occupational disease, accident notification and frequency rates. Often, this information may be available but not accessible because of administrative complexities or legal intricacies. Lack of such vital information hinders the determination and the sound epidemiolog ical and statistical basis for determining priorities in occupational health. Here are some examples of some practices and procedures of pesticide use that should be legally standardized: (1) Sellers or buyers of the pesticide should have a license obtained after participating in a government-sponsored training program and passing a government-standard examination, and the license should be renewed every three years; (2) used containers should be returned to the sellers, who must dispose of them, and, at the same time, the government 166 must have a place for the proper disposal of pesticide containers; (3) the government should support projects to encourage using protective equipment, such as having some funds for a farmer's bank to supply loans for buying protective equipment. The government should have a policy of providing incentives to any companies which sell protective equipment in the industrial sector to think about selling to those in agriculture who also want and need protective equipment. All pesticides should be stored under lock and key so that human beings (especially children), livestock, and pets cannot come into unauthorized contact with them. The locks should be high so as to be out of reach of youngsters. Further, no one should sleep in a room where pesticides are stored. In general, good labeling of pesticides is the most important single factor in their safe use. They should never be transferred to a container usually used for storing food, beverages, or medicines. The herbicide should be stored separately so as to avoid cross-contamination or erroneous use which may result in crop damage. Occasionally, the containers in stores should be checked for corrosion and leaks so that deffective ones can be replaced before they pose a hazard. It is also desirable to remove from storage only the amount of material needed for one day's application. The concentrated or diluted pesticides should not be left unattended in the field or at the site of application. The mixing and preparing of the pesticide dilutions should be done in an open or in a well-ventilated place. Contaminated absorbent material, like sawdust, waste-cotton, rags and soil, should be 167 transferred into suitable containers for disposal. The containers holding unwanted pesticides should not be taken to an incinerator. On the contrary, they should be buried at a depth of at least 50 cm. at a safe disposal site. The liquids can be poured into a pit in such an area. After collecting as much of the spill as possible, a contaminated area, especially in and around houses, should be thoroughly cleaned with plenty of water containing a detergent or washing soda. The washed area should be used only after it has dried. Spray fluids may become surplus owing to miscalculations in estimating the requirements, failure to apply all the prepared spray, poor performance of the sprayer, etc. The unwanted spray fluid should be first offered to a person in need of it. If no one needs it, the spray fluid should preferably be disposed of in the waste disposal area. To be successful, these and other aspects of education must be directed toward the improvement of human health. In this study, we found that 90% of respondents sold the containers or gave the pesticide away; they never had a specific place for disposal. These problems can be overcome by the collection and collation of baseline information on conditions of health and hazards in the working environment. To this can be added the collation of data in representative samples of workers' health and of work places of various types and sizes. Investigations should be carefully evaluated for any pesticide to which workers will be exposed. The toxicologist is guided in selecting the studies most relevant for safety evaluation by an understanding of (1) the physiochemical properties of the chemical; (2) the conditions of use and degree of exposure, including 168 the possibility of generating toxic derivatives when the chemical is mixed with various chemicals; (3) the type of exposures which may be continuous or accidental; and (4) possibly toxicologic information already available on other chemicals with similar chemical structure and reactive chemical groups. When a new chemical is being used on a large scales careful clinical surveys of the workers and monitoring of the work places should be planned. An important objective of experimental and clinical
ll investigations in toxicology is the proposal of II safe levels of exposure. Measurements of chemicals or their metabolites in biologic material (expired air, bloods urine) allow estimation of the intensity of exposure to the chemicals. Biologic monitoring may also be used to detect early biochemical changes (e.g. s acetylcholinesterase inhibition) before the occurrence of adverse health effects. The study shows that workers should be given a chance to participate in a well-planned health and safety training program which can give them a good understanding of using protective equipment. After the training, they should be allowed to practice for themselves using the equipment. At first they may experience discomfort (as with a mask or boots)s but after a while they will become used to the equipment. Only then will they be sure of the value of protective equipment, and only then will there be a real attitude change. Private chemical companies have recently shown some interest in conducting surveys of the health of pesticide users. But ultimately it is the government that must take decisive action in following up on the survey results and protecting the health of agricultural workers. 169 Afirst step would be to arrange training sessions throughout the country in the proper use of pesticides. Factory workers who have been wearing protective equipment in handling toxic chemicals could be used as resource people in the health and safety training. To safeguard the health of Thai agricultural workers, everyone involved in the use of pesticides should be required to complete this training. . Using the results of this study, the Ministry of Health and the Ministry of Agriculture should have an appropriate policy action, and work together to solve the pesticide prcb1em and also improve the effectiveness of protective equipment for the agricultural sprayers in Thailand. 170
APPENDIX A INTERVIEW SCHEDULE
An Assessment of the Knowledge, Attitudes, and Actual Behavior Regarding Pesticide Application By Thai Orchid Nursery Workers
VENIKA KAMLANG-EK Public Health Sciences School of Public Health University of Hawaii
The study consists of four parts:
1. Aquestionnaire pertaining to life style and social background 2. 'A questionnaire for knowledge 3. Aquestionnaire for attitudes 4. Aquestionnaire for pactices and a checklist of actual behavior using pesticides It is important to answer all items. If you have any questions, please ask the supervisor before you begin. Thank you for answering the questions.
Name of Interviewer ------Start interviewing at ------finish at Total Minutes ------171 Part I. Background and Life Style Questionnaire Section 1. I.D. No. --- Name ------Household identification number: ---- Address ------District ------i. Age at last birthday: years Birthdate: / / Month Day Year 2. Sex: (l) Male (2) Female 3. Marital Status
(1) Married (2) Single (3) Widowed (4) Divorced (5) Separated 4. Educat ion (1) lower than grade 4 (2) completed up to grade 4 (3) finished grade 6 (4) high school (5) university or college (7) other (specify) ------5. Orchid Nursery position (1) owner (2) temporary employee (dat ly) (3) permanent employee (monthly) 6. Did you work on other farms before the orchid nursery? (1) Yes (2) No 7. Do you drink alcoholic beverages? (1) No. (2) Yes. If yes, what kind of alcoholic beverages do you drink? (1) beer) (2) liquor (3) home brewed liquor (7) Other (specify) _ 172
8. At the present time. do you smoke cigarettes? (1) Yes. (2) No. 9. If yes, how much do you smoke? _____ cigarettes per day 10. How long have you been smoking? years 11. What kind of cigarettes do you smoke? (l) Filter (2) Non-filter --1 KRONGTHIP --4 PRECHAN --2 SAM IT --5 GRADTHONG 3 .SAIFON 6 KRUNGTHONG
Part II. Directions Please put a check mark (J') next to your answer. (There are no right or wrong answers.) Choose only ONE answer. If you believe that the statement is completely correct, check #1. Example: 1. Insecticide is useful for agriculture. (/) 1. Correct ( ) 2. Not sure ( ) 3. Incorrect
Part II. Questionnaire for knowledge in using pesticides When spraying insecticide, what is suitable clothing for spraying?
1• Pants (0) short (l) long (0) others 2. Shirt (0) short sleeved (1) long sleeved (0) other 3. Raincoat (1) Necessary (0) Unnecessary 4. Shoes (0) slippers (0) rubber shoes (1) boots (0) no footwear 5. Hat (1) Necessary (0) Unnecessary 173
6. Mask (l) Necessary (0) Unnecessary 7. Gloves (1) Necessary (0) Unnecessary
Part III. Attitudes towards the use of insecticides and protective equipment Attitudes Questionnaire What do you think of the following statements? Please check only one choice for each statement: Agree, Uncertain, Disagree (~ indicates the correct answer.
Option Agree Uncertain Disagree Statements (1) (2) (3)
1- A hat offers protection from the 0 0 (1) fumes of insecticide during spraying but it is inconvenient to use.
2. Although a mask which covers the 0 0 (1) mouth and nose is very good for workers spraying insecticide, it sometimes makes one feel uncomfortable and easily tired.
3. Gloves are very important when 0 0 (1) spraying insecticide but their use should be optional.
4. Long-sleeved shirts and long pants 0 0 (1) are inconvenient for working.
5. Wearing a raincoat to cover your 0 0 (1) shirt makes it difficult to spray insecticide. 174
Option Agree Uncertain Disagree Statements (1) (2) (3 )
6. It is not necessary to wear boots 0 0 (1) while spraying insecticide because the feet do not come in contact with insecticide.
7. It is not necessary for healthy 0 0 (1) people who do not have allergies to wear protective equipment
Part II1. Section 1. Practices Questionnaire When spraying, what do you usually do regarding the following? 1. Pants: What kind of pants do you usually wear? (0) Short (1) Long (7) Other (specify:----- 2. Shirt: What kind of sleeves do you usually wear? (0) Short sleeves (1) Long sleeves (7) Other (specify: ) 3. Shoes: What kind of footwear do your usually wear? (0) Slippers (0) Rubber shoes (1) Boots (0) Never wear any shoes
Part IV. Section 2. Checklist of Behavior in Using Pesticide (To be completed by researcher following observation/interview) 175
J.D. No. ----- Name ------Regular time of spraying insecticide _ Observation at household: They use protecti ve equipment or not. (Check the action first and see whether they do it or not.) 1. Put a hat on (1) Do (0) Don't 2. Wear goggles (1) Do (0) Don't 3. Wear a mask (1) Do (0) Don't 4. Wear gloves (1) Do (0) Don't when they mix insecticide
5. Wear gloves (1) Do (0) Don't when they spray insecticide 6. Wear a raincoat (1) Do (0) Don't 7. Wear a shirt (1) Long sleeves (0) Short sleeves (0) Don't wear a shirt 8. Wear pants (1) Long pants (0) Short pants 9. Wear boots (1) (0) Don't (1) Other, specify:
Part V. Health examination of orchid worker 10 No. ------No. of blood sample _ Name ------Age Sex _ 176
1. Nature of work: (1) Mixing (2) Spraying (3) Mixing + Spraying 2. How many times do you spray each week? times 3. How many rai of land do you have? rais 4. How many people do you have helping you to spray or mix and how long does each person spend helping you each time? Persons Hrs/person 5. When you sleep, do you take a sedative? () Take every time () Take sometimes () Never take 6. Did you sleep well last night? ( ) Didn't sleep () Woke up sometimes ( ) Slept well 7. Do you have a cold now?
() No, I don I t () Yes, I do. 8. If you have a cold now, did you take medicine for it? () No, I didn't () Yes, I did 9. Did you have any of the following symptoms today? (Mark only the symptoms which the patient experienced. Skip the others.)
Symptom Degree/amount ---- Have a symptom Never Fever Headache Weakness Dizziness Vomiting Salivating Thirsty Eye i rritati on 177
10. Examination of pupils both before and after spraying or mixing: Pupils Before spraying or mixing After spraying or mixing Size: Normal Constricted Size: Normal Constructed 178
APPENDIX B RESULTS OF PRELIMINARY INTERVIEW QUESTIONNAIRES FOR PERSONS ENGAGED IN AGRICULTURE
Total of agriculture workers = 170 participants Sex: Male = 128 persons Female = 42 persons 1. Age of participants 10-19 4 persons 20-29 30 30-39 43 40-49 49 50-59 25 60-69 14 No answer 5 2. Number of participants in each district 2.1 Luksong Subdistrict Nongkneem Region 61 2.2 Bangborn Subdistrict Bangkhunthian Region 8 2.3 Samphran District Nakorn Pathom Province 6 2.4 Banmai Subdistrict Nongkhangphlu Region 6 2.5 Thaseo Subdistrict Nakorn Pathom Province 3 2.6 Suansom Subdistrict Samutsakhorn Province 4 2.7 Thamai Subdistrict Krathumbeen District, Samut Sakhorn Province 16 2.8 Bangyang Subdistrict Samut Sakhorn Province 62 3. Education Read/write lower than grade 4 16 Grade 4 ·77 Higher than grade 4 77 4. Orchid nursery position Owners 99% 5. How long have you used insecticides? 1-5 years 51 6-10 years 71 More than 10 years 48 6. When you spray insecticides, do you spray by yourself? Yes 113 No 57 179
7. Please tell the name of insecticides usually used: No. Trade name Common name 1. Carsade Dimethoate 2. Diphos 50 Dich1orvos 3. Difolatan 40 Captafo1 4. Difo1atan 80 Captafol 5. Dimethoate Dimethoate 6. Dithane IF Mancozeb 7. Di ovit Wettable Sulfur 8. Brassica1 PCNB or Quintozene 9. lannate Methomy1 10. Mitac Amitraz 11. Azodrin Monocrotophos 12. Orthocide Captan 13. M-777 Dicofo1 8. How many times do you spray insecticide each month? 4 times per month 99% 9. Have you used the insecticide named "lannate"? Yes 10. When you spray "Lannate" in the nursery, do you mi x it with other pesticides? No 11. During June-September every year, what kind of insecticides do you use? Same list as item #7 12. At what time do you spray insecticides in the nursery field? In the morning 49 persons In the afternoon 21 In the evening 46 In the morning and evening 52 13. Have you or your family suffered from pesticide poisoning in the last year? No 14. If you have ever suffered from pesticide poisoning, where did you usually seek treatment? Cl inic 31 persons Hospital 26 Self-treatment 15 No treatment 19 180
15. Will you agree to answer a questionnaire from an interviewer at your nursery during May-September? Agree 95%
16. Will you agree to allow about 1 ml. of blood to be drawn for testing? Agree 99% 17. Will you agree to participate in health training, if it is offered? Agree 80%
THANK YOU FOR ANSWERING THE QUESTIONNAIRE 181
APPENDIX C THE TINTOMETRIC TEST AND THE CHOLINESTERASE B TEST
I. Biochemical Methods for Measurement of Effects
Blood cholinesterase testing can be used in examining slow, chronic poisoning cases, particularly with organophosphates which are known to form a stable complex with cholinesterase. Thus, the monitoring of blood cholinesterase would be most applicable for diagnosing the long-term effects of thiophates or the effects of oral ingestion of true phosphates and carbamates. Analytical methods have been developed for the detection of a variety of compounds that are found inteact or as metabolites in biological samples from workers exposed to pesticides. Such tests are used primarily in research settings to describe patterns of absorption, metabolism, and excretion, to derive exposure limits for occupational exposure, to evaluate the adequacy of these limits and of work practice in field settings, and to confirm the etiology of poisonings for medico-legal purposes. Researchers have reviewed methods used in studies of occupational pesticide exposure, with particular attention to validation in terms of dose-response relation ships, to technical complexity and cost, to the requirements for analytical quality control, and to the utility of these methods for field research purposes. Biological monitoring for intact pesticides or metabolites in agricultural workers is limited to a few chemicals, notably pentachlorophenol, methyl bromide, and chlordimeform. 182 Biological screening of agricultural workers, which is limited at present to pesticide mixers, loaders, and applicators, consists almost exclusively of measurements of cholinesterase activity to estimate inhibition by organophosphate and carbamate compounds. Researchers have reviewed the measurement and interpretation of cholin esterase activity in occupationally exposed populations and the correlation between cholinesterase activity and symptoms of acute and chronic illness among agricultural workers (Coye, Lowe &Maddy, 1986). World Health Organization (W.H.O.) (1986) reported that the most Widely adopted approach is to measure the cholinesterase levels in the blood of patients known or suspected to be poisoned. There are two distinct types of cholinesterase in the blood, erythrocyte cholinesterase and plasma cnolinesterase. There are a number of different names for these substances, which are listed below: 1.1. Red cell cholinesterase. a. Other names: erythrocyte cholinesterase, AChE true, acetylcholinesterase type I. b. Characteristics: acety1-methylcholine is a preferred substrate; excess substrate inhibition. (optimum ACh concentration 10 m.). 1.2. Plasma cholinesterase. a. Other names: ChE, pseudocholinesterase type II. b. Characteristics: hydrolyzes butyrylcholine faster than erythrocyte cholinesterase; no excess substrate inhibition. Witter (1963) mentioned that "there are basically three different techniques for cholinesterase assay in human blood: (1) potentiometric (i.e., pH changes), (2) radiometric, and (3) colorimetric determination 183 of either the reaction products (acetic acid for pH-metry) or the remaining unhydrolyzed substrate. The pH-metry technique has been used most commonly in the past. In a typical case, blood samples are taken from the fingertip or ear and put into a heparinized capillary tube, which is sealed and centrifuged" (p. 537). Brown and Bush (1950) described "cholinesterase activity of people who had been exposed to parathion as ranging from 1 to 8 mg/10m and concluded that 2-8 mg/10m is potentially dangerous" (p. 633). When there are, for example, data on in vivo inhibition of blood cholin- esterases in human poisoning cases, in vitro comparisons against animals could give valuable information about species differences in susceptibility (Sachse &Voss, 1971).
II. Biological Monitoring of Agricultural Workers Expsed to Pesticides: Cholinesterase Activity
Blood cholinesterase tests are valuable tools for determining the danger levels in human poisoning. Their usefulness is particularly apparent for people occupationally liable to constant insecticide exposure. Direct tests for blood insecticide levels and urinalysis for specific insecticide residues and/or specific metabolites offer great promise in detecting early or mild poisoning when the source is known. According to Kasiman (1982), the results of monitoring cholin esterase activity levels should be compared with the individuals' base line levels, and the criteria used in monitoring are as follows: 2.1 25% depression from base line level indicates probable overexposure. 184 2.2 50% depression from base line level indicates serious over exposure. The person should be removed from work until his cholinesterase level returns to normal. 2.3 75% depression from the base line indicates very serious overexposure. The person should rest until his cholin esterase level returns to normal (p. 193).
Both the tintometric and in vitro colorimetric methods were chosen as methods to determine the results of cholinesterase activity in this research. It is necessary to have a second method to confirm data accurately.
1. Tintometric Methods
In 1953, Limperos and Ranta described a simple and speedy colori meter method which had already been successfully used in North America. The principle of this method is that the cholinesterase activity of the sample determines the rate of color change in a system comprised of the enzyme (blood sample), substrate (acetylcholine) and indicator solution (soluble bromthymol blue, green blue at pH 7.2, continuously changing to orange-brown at pH 6.2). The color of the test solutions at the end of 20 minutes was correlated with the final pH by using a pH electrode. The color scale for cholinesterase activity was divided into: orange, 100%; brown, 75%; olive-brown, 50%; olive green, 25%; and green, 0%. Based on this method, a series of permanent colored glass standards calibrated at intervals of 12.5% normal cholinesterase activity was developed for use as a color comparator for field use. The criteria based on the Tintometer method in relation to whole blood cholinesterase are as follows: 185 100% - 75% of normal No actions but retest in near future. 75% - 50% of normal Over-exposure probable; repeat test. If confirmeds suspend from further work with organic phosphorus insecticides for 2 weeks; then retest to assess recovery; 50% - 25% of normal Serious over-exposure: repeat test. If confirmeds suspend from all work with insecticides. If indisposed or ills arrange medical examination. 25% - 0% of normal Very serious and dangerous over-exposure. Repeat test; ifconfirmeds suspend from all work pending medical examination (p. 453). Tintometric methods for estimating the degree of poisoning are well enough developed so that chronically or mildly poisoned individuals can be detected before external symptoms begin to appear. The tinto metric method was described by Edson in 1958. Fingerstick whole blood samples from exposed subjects and from a control (nonexposed) person are allowed to incubate with acetylcholine and the indicator bromothymol blue. Changes in colors reflecting the acid produced by hydrolysis of the acetylcholine s are measured by comparison with color-tinted glass standards. The time required to reach 100% of acetylcholin esterase activity is established with the control samples and then applied to that for the exposed subjects. Values from separate days are not directly comparable.
2. Cholinesterase B Method
The Cholinesterase B test is a colorimetric method for the determination of cholinesterase activity in serum. Wako Pure Chemical Industries, Ltd. in Japan has recently developed an assay kit, Cholinesterase Bs for the simple and accurate determination of cholinesterase activity. Cholinesterase B is an enzyme-coupled assay 186 in which cholinesterase catalyzes the hydrolysis of benzoylcholine, and the choline that is liberated is oxidized in a reaction catalyzed by choline oxidase, resulting in the formation of stoichiometric amounts of hydrogen peroxide. The hydrogen peroxide formed reacts with phenol and 4-aminoantipyrine in the presence of peroxides to produce a red pigment that is quantified spectrophotometrically. The assay has excellent reproducibility and involves only two steps which together requires only about 20 minutes. Cholinesterase B has overcome the disadvantages of conventional assay methods and can be readily adapted to autoanalyzers. The method is quite precise, with good reproducibility. The initial cost of the mini spectrophotometer is approximately double that of the tintometer, but subsequent reagent costs are low. In particular, baseline data can be compared with later values for the same subject (World Health Organization, 1978).
A. Characteristics of the Cholinesterase B Test
1. Simple procedure (2 steps) 2. Rapid assay (approximately 20 minutes) 3. The calibration curve is linear up to 3,000 I.U. 4. Assay results in international units can be easily converted to different pH values 5. Adaptable to autoanalyzers
B. Chemical Principles of the Cholinesterase B Test
When a sample of serum is added to the Substrate-Enzyme Solution (containing benzoylcholine as substrate) and the mixture is incubated at 37 degrees centigrade, the benzoylcholine is hydrolyzed to choline 187 and benzoic acid in a reaction catalyzed by cholinesterase in the serum. The liberated choline is converted to betaine by the action of choline oxidase (also contained in the Substrate-Enzyme Solution). This hydrogen peroxide participates in the oxidative condensation between phenol and 4-aminoantipyrine in the presence of peroxidase to produce a red quinone pigment. The enzymatic reaction is terminated by addition of a cholin esterase inhibitor (neostigmine methylsuphate). The red color developed in a given time period is quantified by measuring absorbance at 505 nm and is directly proportional to the cholinesterase activity in the speci men.
C. Reaction Formula
19 +_ [Q- C- 0 -eH - CH - N (CH OH + H z 2 3)3] 20 Benzoylcholine
ChE ~ [HO-CH -CH -N+(CH )] OH- +~ ')-COOH rn z z 3 3 Benzoic acid
+ _ choline-oxidase - + [HO - CH - CH -N (CH + 20 .. 2H + OOC-CHZ-N (CH Z 2 313'OH 2 Z02 3)3 Hydrogen peroxide Betaine ••• (2) Peroxidase 2 H 0 +~ OH+H C-C .. C-NH ~ H .. C-N ..< :>.. 0 2Z'=./- 3 I 1 2 3C-CII Pheno 1 H C - N C" 0 H -fl C .. 0 3 \ / 3C \/ N N
~4-aminoantiPYrine ~ Red quinone pigment ~.l ~~ ~ max 505 nm ••••• (3)
D. Calibrations 1. Dilute the Standard Solution as indicated in the table below to prepare a series of standard solutions for calibration. 188
Standard Dilution for Calibration
Standard Solution Deionized or Cholinesterase (stock soluti on) Water Activity (1,000 ru/u (ru/u
1.0 m1 1.0 ml 500
2. Using three test tubes, take the diluted standard solution for calibration and Standard Solution (stock solution) as indicated in the table below.
Standard Solution
Test Diluted Standard Standard Solution Cholinesterase Tube Solution for (stock solution) Activity No. Calibration (lUll>
1 0.02 ml 500 2 0.02 m1 1,000 3 0.04 m1 1,990*
*The usual amount of test serum is 0.02 m1; however, 0.04 ml of the Standard Solution was taken in this case. The equivalent cholinesterase activity value given in the table has been corrected accordingly.
3. The assay is then performed as described in Procedure (Wako Pure Chemical industries, Ltd. in Japan). The measured absorbances are plotted against the equivalent cholin- esterase activities of the standard solutions for calibration and a calibration curve is obtained. 189 v. Quality Control
A quality control program is recommended for all clinical laboratories. The analysis of control sera in both the normal and abnormal ranges with each assay is recommended for monitoring the performance of the procedure. The values obtained for the controls should fall within the manufacturer's stated acceptable range.
Calibration curve
Hitachi Spectrophotometer Model 124 Light path: 10 mm Wavelength: 505 nm Control: Blank test
0.6 Absorbance
0.4
0.2
0..A.- ...a-__-"-_---'r--_-.:. _ 500 1000 1500 2000 2500 Cholinesterase Activity (lUll) 190 F. Results
Calculations 1. From the calibration curve: The cholinesterase activity (lUll) of the specimen is estimated by interpolation of the measured absorbance (As) on the calibra tion curve. 2. By calculation: The absorbances of serum (As) and Standard Solution (Astd) are measured against the blank test and the cholinesterase activity in the specimen is calculated as follows: International unit:
Activity (lUll) As x 1,000 = Astd
Conversion of cholinesterase activity (lUll) to ~ pH is performed as follows:
~ pH: pH = (0.00068 x x) + 0.02 (x = activity value in lUll) Sample calculation: Absorbance of serum As = 0.380 Absorbance of Standard Solution Astd = 0.290 Cholinesterase activity (lUll) = 0.380 X1,000 = 1,310 0.290
pH = (0.00068 X 1,310) + 0.02 = 0.91 191
APPENDIX 0 OPERATIONAL DEFINITIONS
1. A sprayer is one who sprays pesticides and is either an employee or an employer. 2. Protective equipment includes such things as a hat, goggles, mask, gloves, raincoat, long-sleeved shirt, long pants, and boots that are used for protecting sprayers from pesticide fumes. 3. Unsafe acts are those in which the sprayers incorrectly applied pesticides and caused dangerous problems for their families and themselves. 4. Unsafe conditions are the situations or conditions where the orchid worker incorrectly arranged the storage, or disposed of the pesticide container or transferred pesticides in the wrong way. 5. Pesticide is a toxic substance that is used for killing weeds, pests, and fungi in the fields.
6. II Rai II is the unt t of area ; n That 1and used ; n 1and measurement and is equal to 0.4 acres (1 acre = 2.5 rail. 7. Cholinesterase is an enzyme that hydrolyzes cho1ineesters and that is found especially in blood plasma. 8. Tintometric methods for estimating the degree of poisoning are well enough developed so that chronically or mildly poisoned individuals can be detected before external symptoms begin to appear. This method was first described by Edson (1958, pp. 21-25). 192 9. Cholinesterase B test is a colorimetric method for the determination of cholinesterase activity in serum. Wako Pure Chemical Industries, Ltd. in Japan recently developed this assay kit, Cholin esterase B, for the simple and accurate determination of cholinesterase activity. 10. SGOT is the acronym for Blood (Serum) Glutamic-Oxaloacetic Transaminase. The purpose of this test is to detect and differentiate between varying forms of liver disease or severe heart problems. 11. SGPT is the acronym for Blood (Serum) Glutamic-Pyruvic Transminase. The purpose of this test is to detect and evaluate treatment of acute hepatic disease and distinguish between myocardial and hepatic-tissue damage. 193
APPENDIX E LOCATION AND MAPPING
The main orchid growing areas of the world are in Latin America, Asia and the Pacific. There are more than 1,000 species of orchids found indigenous to the regions stretching from Japan and Korea down the Indo-Malaysian regions to New Guinea and Australia. The variety of orchid for cut-flowers that was first utilized (1965) was the Dendrobium Pompadour which is commonly known as IIMadame" among 1ayman orchid growers. This Dendrobium hybrid originated in France more than 30 years ago as a result of intensive breeding work. Soon after that discovery, some orchid enthusiasts in Thailand imported a few plants of the hybrid and cultured them for fun. It was found later that the environmental conditions in Thailand are highly suitable for this variety of orchid. It, thus, gained widespread popularity within a very short period of time thereafter and, as a result of intensive propagating effort, has become a favorite variety for the cut-flower business. One important factor that has persisted for more than ten years from the time that Thailand first started exporting orchids is that orchid users overseas are well accustomed to the Pompadour orchid variety as evidenced by the constant presence of such flowers from Thailand in almost every prominent flower stand in Europe, indicating its widespread popularity abroad. It has always been an important policy to continue to maintain and improve the quality of exported flowers. For technological reasons as well as common observation, 194 it is well recognized that repeated growing and propagation of the same variety for extended periods of time and in the same place have a deteriorating effect on flower quality. Orchids by nature are hardy plants and will grow without many problems. However, under conditions of mismanagement, problems come all the same. Some common problems are pests, diseases and certain physiological disorders. For effective control of pests, it is important to identify the lIinvader ll correctly in order to apply the proper control measures. That is the reason why a lot of insecticides and fungicides are used to control pests in nursery plants. Since 1932, Thai people have been ordering many kinds of orchids from Europe, Singapore and Indonesia for their hobby. By 1954, they had developed the techniques for raising orchids and had become educated in the feeding and protection of orchid plants. Three years later in 1957, the orchid farmers established a community for exchanging experience and knowledge which was spread through radio, television, newspapers, and magazines. That was the real beginning of orchid farms in Thailand. In 1957, they started an education program in universities related to agriculture. In 1966, they began to export their production to other countries such as Japan and Europe. There are seven main areas for orchid farms in Thailand consisting of 2,931 acres: (1) Bangkok (1,266 acres composed of sub-provinces Phasi Charoen--442 acres, Taling Chan--300 acres, Nong Khaem--524 acres) and the nearby provinces of Samut Sakhon (343 acres), Nakhon Path om (1,200 acres), and Samut Prakan (54 acres); and only 57 acres from other provinces including (2) Chiang Mai, (3) Nakhon Sawan, 195 (4) Nakhon Ratchasima, (5) Udon Thani, (6) Chon Buri. and (7) Songkh1a per farm. The more than 2,000 orchid farms average 1.2 acres. Bangkok is the capital of Thailand and the center of business. education, banking. communication and transportation. including a large international airport needed to export the orchids by air to other countries. The Chao Phraya River, the main river of Thailand, passes through this region. Most of the area in the central part of Thailand is a large plain suitable for agriculture. Surrounding Bangkok are 24 districts but only three districts have orchid farms and these were selected for the experiment group: Phasi Charoen district with 85 villages in Bangpie. Bangk1anige. Bangk1a and Khongkuang subdistricts.
-- Ta1ing Chan district with 94 villages in Bang1amard. Bangchiuknag, Bangprom, Sa1adang, and Tanweewatana subdistricts.
-- Nong Khaem district with 84 villages in Luksong, Nongkhangph1u and Nong Khaem subdistricts.
The control samples were collected in two districts of Samut Sakhon province which is near the Gulf of Thailand:
-- Krathum Baen district with 54 villages in Bangyang, Suan1onge. Khongmardire. Thaseo. Thamae. Thatarate and Nongnaugkhi subdistricts. 196 Ban Phaeo district 91 villages in Suansom, Khaseadpatana, Khongton, Nongbrue, Nongsonghong and Luksam subdistricts; and also in Nakhon Pathom province.
Sam Ph ran district with 109 villages in Sam Phran, Raikhing, Krathumloum, Krathumsma1, and Aoumyai subdistricts. 3: I1J "'C ...... ", 0 . ~ ~/'\ lIN <-I. ::s n ·10 en VI 0 ...... ::l" I1J .....-I, I1J ::s .\ /~J43) 0. \ ·'L\ f\ ( /7\.. ---/ 3' ~ ~ ''\
~16---- \ f'
Andaman Sea ..... 1.0 "'-J
• 12
UeRGUI o Provinces of Thailand ARCHIPELAGO ' 1 Antt rp.,...... l' ~ "'i_I
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1 4ng Thong 37 PI"l8't'IO " 2 Buriram 38 P!'l.tc".~un 3 Chlcho!ngsa.... 39 Ph.lch.bu~, Gulf .. ena, Nit '0 Pt\lch~t ~ .' !) .. 5 Cl'lliylprhH'1"'. A 1 PP''tluanu1o'' of 6 Chanthabur. 42 Phrl N !'lor: i Chiang ~a' 51 yuflha~'A '~r~ e Chiang Rai 43 Ph'ac 47 . Thailand .. Chon Sun .U Phull;lt 10 Chumphon 0I! Prachin Bun \ /' 11 Kala.,n ..e P'achu'D Kl'l.r-o khol"'t ~ P~el 12 Klmphaeng 47 Ranang ' t3 Klnchan.burl ole Ratchaburr ..J '4 Khon Klen 019 Rayon; 15 Krabi 50 Ro; Et 62 16 Krung Thep 51 SakC'n Nakhon M.".n,k."<.'l" 52 Samul Praltan 17 Lamping S3 Sam...1 Sakhon 18 Lamgtu,,1n SA Sim~t Songk"roim '35 '" li Loei 55 S,ra Bur. 20 L.op aura 56 Satu' 21 Mae Hong Son S7 SinlJ B.,r, ~ 22 Maha Sar.kham Slukel i R n se 23 N.k"on NIY0io,. 59 SongkhliJ "ftllbt 24 Nakhon Palhor" 60 SUU'IC'!h" 25 N.""on Phanom 61 Suph,n Sur, 2e Nakhon RatchUIrr.a 62 Sural T".nr 27 Nlk.hon 5,wln 63 Sunn 28 Nakhon 5i Tharr-mclr,1l 6.t Talt 29 Nil' 65 Trln~ Strait 30 NaralhlWl1 66 Tr.! 31 Nong Khl' 67 Ubcn R.tel'll""" 01 .• ,56 32 Nonthabur. 66 Udcn Thanl 33 Pal"um ltla;l' 69 U'h'l ThjJnl Ma/ar:r:a ..-'~~i 34 Patlan. 7'0 UlfarJchl ~-'! ~ J~ Phlngng. :'1 "la ~ 36 Phaltt1a'ung :'''} YuC'lhon po::. r-ces ""le -e-e I.,~·!' -"~'C~ I~ t-e: ·"s"E"~"I..' ".~J!~;S y 1\0 i lYO I~- i I o lID 100 'lnlllo. '00 '-. 1O(
198
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Map 2. Strategic Area for BMR Development
198
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e10pment
APPENDIX F HEALTH AND SAFETY PROGRAM AND PEST CONTROL PROGRAM
Objectives for the health and safety training program:
1. To understand the hazards to pesticide applicators by oral contact, inhalation, or skin exposure and to learn how to protect themselves; to learn first aid for accidents in using pesticides.
2. To determine how to choose, use, and care for protective equipment to increase safety in spraying pesticides.
3. To know how to use pesticides correctly and how pesticides work, including the following: -- mixing and storage of pesticides how to properly handle damaged containers becoming aware of pesticide residues in the environment
.... \0 \0 Learning Experiences
Learning Teacher Student Objectives Contents Duration Activities Activities Materials
Health and Safety training Toxicology 1 day for -Explain new -Listen -Chart program for pesticide -How poisons work theoretical words and make applicators in the -Measures of exposure training it easy to -Take notes -Overhead Experimental group -Dose-effect relation- understand projector ships 9:00-10:00 a.m. -Ask quest ions 1. To understand the hazards -Other factors -Use examples when they -Slides to pesticide applicators by affecting toxicity don't under- oral contact, inhalation, or -Toxicity testing -Relate the stand skin exposure and learn how -Acute toxicity teaching to the to protect themselves; to --Chronic toxicity work which the learn first aid for students will be accidents in using pesticides Pesticide poisoning S)lnptoms doing -Respiratory exposure -Skin exposure -Give summar ies of the main First aid for pesticide Break 15 mins. points poisoning -Discuss the problems
No o Learning Experiences
Learning Teacher Student Objectives Contents Duration Activities Activities 14aterfa15
2. To determine how to -Protective clothing and 10:15 a.m. -Show equipment -Participate -Overhead choose, use and care for other safety devices 12:00 p.m. in the projector protective equipment to -Use hand-out activity -Chart increase safety -Types of protective in spraying pesticides clothing -Explain the -Listen -Slides method of -Coveralls cleaning -Aprons equipment -Spray suit -Gloves -Give summaries -Hats of the lIain -Boots points -Care of clothing -Discuss the -Types of eye, mouth problems and face protection (e.g., goggles)
-Types of respiratory equipment (e.g., gas masks)
-Use and cleaning of respirators
N ....o Learning Experiences Learning Teacher Student Objectives Contents Duration Activities Activities .'ateria15
3. To know how to use -How to handle 10:15 a.m. -Demonstrate -Observe the -Slides pesticides correctly pesticides to mixing of method of and how pesticides work 12:00 p.m. pesticides mixing -Transporting including the pesticides -Test how much following: -Listen students -Storing pesticides already -mixing and storage -Answer -Shelf life of know questions -how to properly handle pesticides -Give summaries damaged containers -Mixing and loading of the main -becoming aware of pesticides points pesticide residues -Pesticide spills in the environment and fire -Personal clean-up
N o N Objectives for pest control program
1. To understand the most common features of pests, how they develop and the kinds of damage they do. 2. To analyze the various types of pesticide available to control pests and how to combine these types for the best results.
Learning Experiences
Learning Teacher Student Objectives Contents Duration Activities Activities Ilateria 15
Pest Control training -Introduction 1 day for Program for pesticide -Definition of "pest" theoretical applicators in the and training control group -development of insects
1. To understand the most -pesticide damage: 9:00- -Get the student's -Listen and -Overhead common feature of pests, -lffe cycle and 10:00 a.... attention in pest take notes projector how they develop; and the environment development and -Chart kind of damage they do -pesticide residues pesticide residues -Slfdes -Give a summary 15 min. break
N o w Learning Experiences
Learning Teacher Student Objectives Contents Duration Activities Activities Materials -Overhead Z. To analyze the -pesticide classifications 10:15 - -Present the projector various types of and formulations 11:30 a.m. facts and pesticides you can information -Labels and Labeling -Slides use to control pests and how to combine -Pesticide compatibility -Use hand-outs -Listen -Chart these tyPp.s for the and combinations best results for controling pests -Ask one of the -Answer the students to questions describe the debt ls about labels
N o ~ 205
APPENDIX G
TRANSLATI ON OF THE II BOOKLET OF HEAL. TH AND SAFETY IN USING PESTICIDE"
Pesticides are "Pest-Killers" But They Could Also Be a Down Payment on Death for Humans
Pesticide use for the control of plant, human and animal pests is presently common throughout the world. Pesticide benefits relative to their uses in agriculture and in public health are common1y known, since they are well documented, but the pesticide hazards to human society and the environment are less well understood. In Thailand, chemical control is mainly used for plant pest control. Agriculture is growing in importance in Thailand where there are many kinds of fruit, vegetables and flowers. Orchid nursery growing is becoming a profitable business for export to many countries in Europe and to Japan. For effective control of the orchid pests, it is important to use insecticides and fungicides. Many kinds of insecticides are being used to protect the blooming orchids that are exposed to pests. When there is an incidence of plant pest outbreak, the first thing that an administrator will think of is what kind of pesticide should be used. For most farmers, pesticides are used for only one purpose, and that is to control plant pests as quickly as possible. The workers can mix many kinds of pesticides to spray at the same time and there fore they tend to use quite a lot each time. They take no time to consider whether the pesticides they are now using are or will be 206 hazardous to their health (in most cases farmers spray or dust their own pesticides) or are polluting the environment, which results in unsuitable conditions for human life. Rarely does any pesticide kill all the target pests. Each time a pesticide is used, it selectively kills the most vulnerable pests. Some pests avoid the pesticide, and others are able to withstand its effects. Pests that are not destroyed pass along to their offspring the trait that allowed them to survive. Finally, the pesticide users need to find a substitute for the pesticide that they have been using, and still they cannot solve their pest problems. Every year they have to order more pesticides. The amounts of pesticide ordered in 1974 (9,000 tons) and in 1980 (24,000 tons) show an increase of more than double. In the next 20 years, the increase will surely be much more than this, and agricultural workers should think about how pesticides will accumulate in their bodies day by day. If you collected money day by day, you would be rich. But it is not the same with pesticides. Some day you might get sick from an unknown cause, and you could not be sure if it came from the toxicity of pesticides which had accumu lated in your body to the point of chronic disease. Finally, when you got sick, you would spend your money to cure the disease, and that would be your final decision. Some people might not see the connection between pesticide misuse and chronic disease, and might not take pesticide safety seriously, because it might take a long time before the pesticides affect them or their families. 207 There are a lot of unsafe acts happening all the time. People become more and more careless because they can walk back and forth between their houses and their work, and so they never wash their hands before having lunch or smoking cigarettes. Farmers dispose of pesticides without considering the environment; the pesticides enter the water and air and, finally, fish and birds die through unintentional or accidental spillage and dumping. Another problem is through direct application in agriculture; farmers spread pesticide through their unprotected neighborhoods causing public health problems. It is important to understand that pesticide containers such as bottles should not be sold. Do not be so concerned about making a little extra money that you push a dangerous situation onto the public. Someday those bottles will be reused, and they might return to your community again. Polluted irrigation systems can harm crops, soil, landscape, livestock, and forests, and constitute the major direct or intentional route of introducing pesticides into the environment. They can cause illegal residues in crops, milk, fruit, vegetables and meat. Most farmers do not have enough knowledge about pesticides, and this lack of knowledge increases the possibility of pesticide residues being left in food. That is the worst consequence of pesticide misuse, which nobody seems to think about. When there is an increased demand for insecticide, there is more opportunity for insecticides to accumulate in the bodies of sprayers. 208 How Pesticides Harm Man
At present, we can see various types of pesticide for sale in the market. The pests of orchids include aphids, bugs, mites, thrips, insects, snails, etc. They can damage any part of the plant, including the flowers. There are many types of pesticide formulations (wettable powder, emulsifiable concentrate, granules and liquid). Each type of pesticide formulation has both advantages and disadvantages. Choosing among them should depend on such things as the site of application, safety to man and the environment. Pesticides are poisonous to plants, animals and humans, and can cause injury. They are toxic. The product hazard--the danger that injury will occur to man--depends on the toxicity of the active ingredient plus the exposure to the product. Pesticides enter the body by three routes: being swallowed, being inhaled and penetrating the skin. Many accidental pesticide deaths are caused by eating or drinking the product. But some mixers, loaders, and applicators die or are injured when they breathe a pesticide vapor or get pesticide on their skin. Repeated exposure to small amounts of some pesticides can cause sudden severe illness. Most pesticides can enter the body through the skin. We may get more into our bodies this way than we would by accidentally swallowing or inhaling it while working. With some pesticides, skin contact alone can cause death. It depends on the toxicity of each pesticide, which ranges from low toxicity (comparatively free from danger), to moderate toxicity, to high toxicity. Pesticide poisoning may even result from continuous contact, by absorption through the skin, by the inhalation 209 of the toxic vapor by workers in the course of normal handling of the material, or by swallowing the pesticide accidentally. The exact mechanism by which pesticides affect human beings and other mammals is not known in all cases. However, some of the signs and symptoms of pesticide poisoning are known. The user of pesticides should become familiar with these signs and symptoms. Early recognition of poisoning, prompt removal of the source of exposure, and correct treatment may save a life. There are two general types of toxicity: acute and chronic. Acute toxicity refers to the ability of a pesticide to cause injury, sickness or death as the result of a single or short-term exposure. Chronic toxicity refers to the ability of a pesticide to cause injury, sickness or death as the result of a long-term exposure.
Symptoms of Pesticide Poisoning
You should know what kinds of sickness are caused by the pesticides you use. We also should know the conditions under which each type of pesticide may make you sick. There are two kinds of symptoms of pesticide poisoning. Some only the victim can notice, such as nausea or headache. Others, like vomiting, also can be noticed by someone else. All pesticides in the same chemical group cause the same kind of sickness. This sickness may be mild or severe, depending on the pesticide and the amount absorbed. But the pattern of illness caused by one type of pesticide is always the same. Having some of the signs and symptoms does not always mean you have been poisoned. Other kinds of sickness may cause similar signs and symptoms. Headache and a feeling of being unwell, for example, may signal the start of many 210 kinds of illness. It is the pattern of symptoms that makes it possible to tell one kind of sickness from another. Get medical advice quickly if you or any of your fellow workers have unusual or unexplained symptoms when starting work or later the same day. If you suspect a person has been poisoned, do not leave him alone. Do not let yourselves or anyone else get dangerously sick before calling your physician or going to a hospital. It is better to be too cautious than too late. Take the container (or the label) of the pesticide to the physician. Never carry pesticide containers in the passenger space of a car or truck.
Synthetic Organic Pesticides
Organophosphates--Most of these are insecticides, miticides or nematicides. Some cornmon ones are parathion, monocrotophos (Azodrin) and diazinon. They injure the nervous system by inhibiting cholin esterase, an enzyme. The signs and symptoms go through stages, which normally occur in this order: Mild Poisoning - fatigue - headache - dizziness - blurred vision - excessive sweating and salivation - nausea and vomiting - stomach cramps or diarrhea Moderate Poisoning - unable to walk - weakness - chest discomfort - muscle twitches - constriction of the pupil of the eye - earlier symptoms become more severe 211 Severe Poisoning - unconsciousness - severe constriction of the pupil of the eye - muscle twitches - secretions from mouth and nose - breathing difficulty - death, if not treated
Illness may be delayed a few hours. But if symptoms start more than 12 hours after you are exposed to the pesticide, you probably have some other illness. Check with your physician to be sure. Repeated slight exposures to organophosphates and other cholines terase inhibiting pesticides can cause a progressive and gradual reduction of cholinesterase activity. Only slight, if any, indications appear before severe symptoms occur suddenly from a slight exposure. Symptoms of such a gradual poisoning are weakness, poor appetite and a vague feeling of discomfort or uneasiness. Gradual poisoning by organophosphates and carbamates can be detected early by periodic blood tests for cholinesterase activity. The initial test should follow several weeks of no exposure to these pesticides to obtain a normal value. Such a pre-exposure test may be of value in diagnosing poisonings even if periodic tests are not made. Carbamates--The only carbamates likely to make you ill on the job act almost like organophosphates. Some common carbamates are aldicarb (Temik), methomyl (Lannate, Nudrin) and carbaryl (Sevin). They produce the same symptoms as organophosphates if we are poisoned by them. But the injury they cause can be corrected more easily by a physician. For this reason, most carbamates are safer than organo- phosphates. The label will warn us of the danger. 212 Data from Siriraj Hospital, which covers mostly the urban Bangkok population, show that during 1980-1984 there were a total of about 1,700 cases of pesticide poisoning, mainly females in the 15-29 age groups. About 500 cases were in the 0-12 age group, which is suggestive of the accidental poisoning of young children. In 1985, the Public Health Ministry reported that they received 2,600 cases of pesticide poisoning from the whole country (73 provinces), and provinces such as Kanchanaburi, Sukhothai, Nakhon Pathom, Samut Sakhon, Chachoengsao, Nakhon Suwan, and Nakhon Rajchasima had more than 100 cases each. No data were found to evaluate the prevalence of health hazards associated with chronic pesticide exposure.
First Aid Procedures
If you get a pesticide on your skin: - Remove the pesticide as quickly as possible. Remove all contaminated clothing. Prompt washing may prevent sickness even when the spill is very large. Do not forget about hair and fingernails. Wettable powders and other solid formulations or suspensions are easy to remove with plain water. So are most emulsifiable concentrates and emulsions. However, soap or detergent should be used if readily available and its use does not delay washing with water. Solutions of pesticides in petroleum oil or other solvents are harder to remove without soap or a detergent. Detergents work better. Washrooms and emergency field washing facilities should have detergents rather than plain soap. If you splash a pesticide into your mouth or swallow it: - Rinse out mouth with plenty of water. - Drink large amounts of milk or water. - Go or be taken to a physician immediately. - It is sometimes dangerous to cause vomiting; follow label directions. If you get a pesticide in your eyes: - Flush eye thoroughly with clear water. - Go or be taken to a physician immediately. 213 Protecting Your Body
Pesticides can enter the body in many ways. The main ones are: - getting the pesticide on your skin or in your eyes - inhaling it - swallowing it.
To prevent this, we must wear protective clothing and equipment. No safety recommendations can cover all situations. Common sense should tell you to use more protection as the toxicity of the pesticide or the chance of exposure increases. The pesticide label will tell you the kind of protection you need. Remember to bathe, using a detergent, when you finish working with pesticides or pesticide-contaminated equipment. Any time you spill a pesticide on yourself, wash immediately.
Protective Clothing
Body Covering--Any time you handle pesticides, you should wear at least: - a long-sleeved shirt and long-legged trousers, or - a coverall type garment.
These clothes should be made of closely woven fabric. When handling pesticide containers or very toxic materials, you should also wear a liquid-proof raincoat or apron. Wear trousers on the outside of the boots to keep pesticides from getting inside. Gloves--When you handle concentrated or highly toxic pesticides, wear liquid-proof neoprene gloves. They should be long enough to protect the wrist. Gloves should not be lined with a fabric; the lining is hard to clean if a chemical gets on it. Sleeves should 214 usually be worn outside of the gloves to keep pesticides from running down the sleeves and into the gloves. If spray is being directed upward by a handgun, then the gloves should be worn outside the sleeves. Hat--Wear something to protect your head. A wide-brimmed, water proof hat will protect your neck, eyes, mouth and face. It should not have a cloth or leather sweatband. These sweatbands are hard to clean if chemicals get on them. Plastic "hard hats" with plastic sweatbands are good. They are waterproof and cool in hot weather. Boots--Wear unlined neoprene boots. However, some fumigants are readily absorbed by neoprene boots. Trousers should be worn outside boots. Gogg1es--Wear goggles when there is any chance of getting pesticides in your eyes which will absorb many pesticides. Even relatively non-toxic pesticides can severely damage the eyes. You can wear goggles alone or with a mask. Wash goggles at least once a day. Elastic fabric headbands often absorb pesticides and are difficult to clean. Have some spares so you can replace them often. Respiratory protective equipment--The respiratory tract--the lungs and other parts of the breathing system--is much more absorbent than the skin. You must wear approved respiratory protective equipment such as a mask. 215
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