Water Quality in the Laguna De Bustillos of Chihuahua, Mexico

Water Resources Management III 155

Water quality in the Laguna de Bustillos of Chihuahua, Mexico

H. Rubio Arias1, R. A. Saucedo1, C. R. Lara1, K. Wood2 & J. Jimenez3 1Campo Experimental la Campana-Madera del Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias, Mexico 2New Mexico Water Resources Research Institute, U.S.A. 3Facultad de Zootecnia de la Universidad Autonoma de Chihuahua, Mexico

Abstract

This paper discusses the water within Laguna de Bustillos, Mexico from a qualitative perspective. The following variables were measured at 18 randomly selected sampling sites: lithium (Li), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), antimony (Sb), selenium (Se), thallium (Ti), vanadium (V), and zinc (Zn). Also measured were pH, total solids, total nitrogen (N- ammoniacal and N-organic), temperature, electrical conductivity (EC), and coliforms (total and fecal). A Kruskal-Wallis test was performed for all variables. Of all metal variables, Fe and Mn were present in excessive amounts at all sites reaching values higher than 100 ppm and 1.00 ppm, respectively. Variables with the most undesirable levels were total coliform and fecal coliform that reached values as high as 460*103 NMP/100mL in a sampling point close to an urban city called Cuauhtemoc. These results show the high levels of some contaminates in the Laguna de Bustillos and represent the formal data needed to request help from different regulatory authorities. Keywords: water quality, metal concentration, coliform bacteria, Anahuac, Cuauhtemoc, Chihuahua. 1 Introduction The Laguna de Bustillos is located in the central part of the state of Chihuahua, Mexico. This lake is located in a watershed known as Laguna de Bustillos-

Laguna de Mexicanos (1). This laguna is one of the 60 natural lakes in Mexico (2) and has been an invaluable ecological resource as well as has served many human needs. It is a shallow lake, heavily silted due to soil erosion coming from a denuded watershed and classified as very contaminated (1). Its surface area is estimated at 3,302.7 km2 (3). It has three main gully systems that drain into the lake with the most important one being the Arroyo de la Vieja. The watershed has a human population of approximately 120,000, mostly living in two major cities named Cuauhtemoc and Anahuac. The city of Cuauhtemoc is about 2,300 meters above sea level and most of the city’s surface and sewer drainage goes to the Laguna de Bustillos. Anahuac was once an important industrial center with cellulose, plywood, and viscose plants. Water from these plants drained into the Laguna de Bustillos. In addition, there are other nearby small communities called “ejidos” that are rather scattered in cattle and farming lands. The Laguna de Bustillos at one time contained abundant fish, water fowl, and other migratory birds in the autumn and winter seasons. Local farmers ate fish during the spring and summer as well as using the lake for recreational purposes. The National Commission for Knowledge of the Biodiversity (3) reported the presence of the following fish types: mud darters (Etheostoma australe), Mexican darters (Etheostoma pottsi), and west Mexican redhorses (Moxostoma austrinum) as well as the following endemic species: ornate minnows (Codoma ornate), pupfish (Cyprinodon spp), Chihuahua chubs (Gila nigrescens), Rio Grande chub (Gila pulchra), Chihuahua shiners (Notropis Chihuahua), Tamaulipas shiners (Notropis braytoni), and fathead minnows (Pimephales promelas). Nevertheless, in the period 2000-2002 high incidence of fish mortality occurred and ducks, geese, and other bird species did occur in numbers as high as previously. In addition, the declining environmental quality of the people living close to the Laguna de Bustillos was noted. Data and specific information on the current conditions of natural resources in the Laguna de Bustillos-Laguna de Mexicanos watershed is extremely limited and incomplete. The objective of this study is to provide a general view of the water contamination of the Laguna de Bustillos as the first step for further evaluation of potential harmful effects on human, fish, and wildlife health.

2 Materials and methods

The Laguna de Bustillos is located in the City of Cuahtemoc, Chihuahua, Mexico. Its location is in the polygon: latitude 28° 58’ 12” - 28° 15’ 00” N; longitude 107° 09’ 36” - 106° 15’ 00” W and is 2,300 meters elevation. The laguna is flanked on the north by a mountain called “Sierra Azul” and near some Ejidos close to the mountain’s foot. On the west side are Mennonite colonies, which are famous in Chihuahua for very efficient milk production and a famous Mennonite cheese. On the south are the cities of Cuauhtemoc and Anahuac. On the east are sloping hillsides. It is important to note that Mennonites are good producers who apply high levels of fertilizers on to agricultural lands with subsequent runoff going to the Laguna. Precipitation averages about 480 mm

WIT Transactions on Ecology and the Environment, Vol 80, © 2005 WIT Press www.witpress.com, ISSN 1743-3541 (on-line) Water Resources Management III 157 mostly as rain during summer (July to September) and some snow events during winter (December to February). The average annual temperature is 15.7°C. The area is used mostly agricultural crop and milk production. In summary, the Cuauhtemoc area is considered as the granary of the state. In October 2004, a water sample was collected into a sterile 1 L polypropylene bottle from each of 18 randomly selected sites. These sites will be referred to as sites 1-18. An additional water sample was collected in a sterile 1 L glass bottle to analyze for presence of coliforms. These last samples were transported immediately to the laboratory of the Faculty of Chemistry at the Autonomous University of Chihuahua for coliform determination. Each sampling point was properly geo-referenced. The location of the sampling sites is shown in figure 1.

Figure 1: Sampling points in the Laguna de Bustillos, Chihuahua, Mexico.

Measurements of pH, Temperature (T) and Electrical Conductivity (EC) were taken at the time of water-sample collection. Total Dissolved Solids was determined in the Faculty of Zootechnic in Chihuahua. Water samples for metals were analyzed in the laboratory of the National Institute for Investigations of Forests, Agriculture, and Livestock (INIFAP) to determine Li, As, Cd. Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, Ti, V and Zn using flame atomic absorption spectrometry. A Kruskal-Wallis H-Test (non-parametric statistics) was performed for each metallic variable and differences were noted at the 0.05 level of significance. This test may compare populations that require no assumptions concerning the population probability distributions (4)

3 Results and discussion

According with pH values, the water of Laguna de Bustillos should be characterized as basic water. Values of pH ranged from 8.9 to 9.5. Temperature values ranged from 22° to 29°C, and this depended in the time of selection. The EC values were very homogenous in a range from 4.0 to 4.9 mmhos/cm. Total Dissolved Solids values were very high; this is important because waters with high TDS values become warmer because suspended solids darken the water and absorb heat. Consequently, warm water hold less 02 than cold water, so 02 levels will decrease. The Kruskal-Wallis H-test showed significant differences for the variables As, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn and Li (Table 1); but no significant differences were noted for Cd and Mo. In addition, the elements Sb, Se and Ti were not found at any of the sampling points. The maximum As concentration was found at point 8 reaching 0.255 ppm. This point is near the city of Anahuac where discharges from the cellulose plant are found. The maximum Co concentration was found at points 3 and 4 where it reaches 0.063 ppm at both points. Chromium was found at all sampling points. The maximum Cr concentration was 0.631 ppm and was found at point 13. The data suggested that Cr is homogenously present across the Laguna. It is unknown if this effect is a natural process or might be due to anthropogenic effects. Copper was also found at all sampling points while reaching the maximum concentration at point 7 with 0.977 ppm. The Cu presence in the water may be related to the runoff of agricultural areas where high levels of pesticides are applied. Iron was present at all sampling points and is by far the most abundant metal in the water of Laguna de Bustillos. A concentration of Fe as high as 249.7 ppm was found at point 9. Manganese was another element that was found at all sampling points. A high concentration was measured at point 3, which was 4.75 ppm. Niquel was also found at all sampling points. The highest concentration was found at point 8 reaching 0.607 ppm. The highest Pb concentration was 0.45 ppm and was found at sampling point 13, which is very close to Mennonite owned lands that are characterized by high input agriculture and abundant mechanical devices. Vanadium is a metal commonly put into alloys with Fe and steel. This metal was found at all sampling points and had the highest value of 1.08 ppm at point 9. Zinc concentrations of 0.835 ppm were measured at point 9; however, it is important to point out that this element was detected at all sampled points. This is important because the lethal concentration values for Zn for freshwater fish are in the range of 0.066-2.600 mg/liter (5). Moreover, it is generally known that Zn exerts adverse reproductive effects on aquatic organisms, and fish may accumulate Zn in their body tissues leading to magnification in the food chain. Lithium was also found at all sampling points. The highest value was 0.887 ppm and found at point 11. It is generally known that lithium in water may form lithium hydroxide that is toxic to aquatic organisms and therefore, undesirable for human consumption.

Table 1: The H-Test values, maximum concentration, in elements evaluated in the Laguna de Bustillos, Chihuahua, Mexico.

Element H-Test Value Maximum Point number concentration (ppm) Arsenic 36.03 0.255 8 Cobalt 37.93 0.063 3 and 4 Chromium 47.18 0.631 13 Copper 39.39 0.977 7 Iron 44.86 249.7 9 Manganese 49.15 4.75 3 Nickel 43.63 0.607 8 Lead 50.48 0.45 13 Vanadium 46.08 1.08 9 Zinc 47.48 0.835 9 Lithium 50.15 0.887 11

Table 2: Microbiological results from water samples in Laguna de Bustillos, Chihuahua, Mexico.

Sampling Total Coliform Fecal coliform Total Nitrogen point NMP/100mL NMP/100mL mg/L 1 23*103 460 3.18 2 15*103 4*103 2.96 3 1100 150 3.42 4 9*103 23 3.67 5 7*103 7*103 2.36 6 4*103 23 2.76 7 240*103 43*103 3.27 8 4*103 **DNA 4.68 9 460*103 460*103 5.14 10 1100*102 1100*102 13.81 11 240*103 93*103 7.95 12 9*103 4*103 4.68 13 9*103 9*103 3.42 14 9*103 9*103 2.62 15 9*103 4*103 3.08 16 43*102 23*102 2.97 17 23*103 7*103 3.54 18 9*103 **DNA 4.22 **Data not available

Results with respect to coliform tests and nitrogen determinations are in table 2. Total coliform and fecal coliform counts as high as 460*103 were observed at point 9, which is close to the sewage discharge point of city of

Cuauhtemoc. These results showed that the water of Laguna de Bustillos should not be used, at least at the present time, for recreation because probably is a potential source of infection. Some research has showed that this kind of water may cause dermatitis, gastroenteritis, meningitis, Pontiac fever and leptospirosis (6). Several researchers question the accuracy of using coliform organisms to assess the safety of water arguing that their presence does not necessarily indicate the presence of fecal contamination; however, in this particular study, and because of extremely high levels of coliform indicators, we should assume fecal contamination of the water of the Laguna. Total nitrogen results showed the highest value was obtained at sampling point 10 with 13.81 mg/L. Most of the nitrogen was in the form of organic nitrogen.

4 Conclusion

This study showed that water of the Laguna de Bustillos was contaminated with several elements, but levels of Fe, Mn, Ni, V, Zn and Li must be of great concern, in special for flora and fauna. The risk of infections, especially to rural people that constantly use the Laguna de Bustillos for recreation, can be increased due to the high levels of coliforms found in this study. Also, children and elderly people may be particularly vulnerable.

Acknowledgments

The authors acknowledge and thank the Produce Foundation of Chihuahua for partial financial help. The authors also thank Luis Regalado, Ejidatario en Cuitlahuac; and Edmundo Saucedo and Aurelio Olivas for their help and assistance in data collection.

References

[1] CNA, 2003. Comision Nacional del Agua. Estadisticas del agua en Mexico. Reporte. [2] ADS, 2004. Agua y Desarrollo Sustentable. Situación del agua en Mexico. Junio del 2004/año 2/No. 16. http://www.aguaydesarrollosustentable.com /200406/Articulo3.html. [3] CONABIO, 2002. Comision Nacional para el Conocimiento y Uso de la Biodiversidad. Arriaga, L., Aguilar, V., Alcocer, J., Jimenez, R., Muñoz, E., and Vazquez, E. Coordinadores. Regiones hidrologicas prioritarias. Mexico. [4] McClave, J.T. and Dietrich, F.H. 1985. Statistics, Third edition. Dellen Publishing Company and Collier Macmillan Publishers. [5] WHO, 2001. World Health Organization. Zinc. Environmental Health Criteria 221. Geneva 2001. [6] Levine, W.C., Stephenson, W.T., and Graun, G.F. 1991. Waterborne disease outbreak. 1986-1988. Journal of Food Protection 54(1):71-78.