Parts 1 and 2

TOXICOLOGY INVESTIGATION INTO

BINKILL GARBAGE BIN FUMIGATION PRODUCT

FOR

WASTE AND COMMUNITY PROTECTION DIVISION

PENRITH COUNCIL

Parts 1 and 2

TOXICOLOGIST: CHRIS DERRY UNIVERSITY OF WESTERN SYDNEY JUNE 2010

ABSTRACT

In March 2010 the University of Western Sydney was requested by Penrith City Council to carry out a toxicological assessment of the potential use by residents of Penrith Council area of a commercial pesticide product, Binkill, with potential for exposure to residents, their families and pets.

The product was to be used as recommended by the manufacturer by residents as a slow release fly killer contained in a capsule to be placed by householders in bulk collection bins for green and kitchen waste, with the intention of controlling flies and their immature forms during storage, pending collection as part of a municipal composting operation.

Part 1 of this toxicology report concerns a critical review of the research literature relating to dichlorvos and naphthalene as the main active ingredients. This review was not to be merely a summary of findings in relevant literature, but an evaluation of those findings with relevance to the safe use of the product in the intended household setting, with exposition of any problems which might be envisaged from a toxicological perspective.

Part 2 of the report is an original health risk assessment based on the use of Binkill itself in terms of the device which is used to contain the active ingredients, labelling of the product packaging and device, risk to Penrith Council staff or public in terms of storage, handling use and disposal of the product, and potential local threats to the environment as a consequence of using the product. In this section potential hazards were identified, risks characterised and a framework established for their prioritisation. Information gathered in terms of this scientific research was required to inform Council to enable them to take proactive measures for managing risk, and to enable them to move forward with the current widely-supported recycling program, with regard to duty of care towards Penrith City residents, visitors, staff, and others.

Some initial conclusions of the investigation were that dichlorvos was a good pesticide of choice for the intended application in terms of its relatively low health risk, effectiveness in killing adult flies and immature forms of the family Muscidae, ability to dissipate rapidly, and ease of availability and use.

Problems with which Council should be concerned in terms of the intended, Council- sanctioned use were identified and described with recommendations for Council action. The main problems included labelling inadequacies, visible chips of pesticide material outside the capsule in the surrounding plastic wrapping, and inadequate child-proof nature of the packaging. A number of other items with acceptably low risk were identified for the information and general consideration of Council and the manufacturer.

In addition to the specific safety recommendations mentioned above, suggestions for educational material for residents, and a controlled system for distribution of the product at residential level, were made.

TOXICOLOGY REPORT ON

BINKILL GARBAGE BIN FUMIGATION PRODUCT

FOR

WASTE AND COMMUNITY PROTECTION

PENRITH COUNCIL

PART 1: TOXICOLOGY REPORT ON DICHLORVOS AND NAPHTHALENE

TOXICOLOGIST: CHRIS DERRY UNIVERSITY OF WESTERN SYDNEY JUNE 2010

INDEX

SECTION PAGE DICHLORVOS 3

Introduction 3 Status of dichlorvos in Australia 3 Background to the organophosphate (OP) pesticides 7 Toxicity of dichlorvos relative to other substances 8 Forms of dichlorvos pesticides in use 9 Why dichlorvos is regarded as safer than many other pesticides 10 Present uses in Australia 11 Application methods which may be prohibited in Australia 12 Future of pvc resin strips for small space fumigation 13 Future of dichlorvos/naphthalene blocks for small space fumigation 14 Physiological action of dichlorvos 15 Health outcomes of poisoning 16 First aid treatment 19 Environmental toxicity: animals 20 Environmental toxicity: plants 20 Environmental fate 20 Identifiers of dichlorvos 21 Properties of dichlorvos 21 Storage of dichlorvos 22 Spills and leaks 22

NAPHTHALENE 24

Sources and qualities 24 Exposure and health effects 24 Mode of action 27 Toxicodynamics/kinetics 27 First Aid 27 Ecological effects 28 Properties of naphthalene 28

REFERENCES 30

APPENDIX 1: DATA BASES REVIEWED 33

TABLE PAGE

Table 1: Substances less toxic than dichlorvos in air 8 Table 2: Substances more toxic than dichlorvos in air 9 Table 3: Method of application, and preliminary APVMA recommendation 12

Disclaimer: The report was produced after consultation of the resources shown in Appendix 1 and includes comments by the toxicologist. The contents do not represent the official opinion of the University of Western Sydney. 4

DICHLORVOS

INTRODUCTION

Part 1 of this toxicology report is based on a critical review of the literature relating to dichlorvos and naphthalene as the main active ingredients in the fumigant product, Binkill. In other words, it is not merely a summary of findings in relevant literature, but an evaluation of those findings with relevance to the safe use of the product in an intended household setting, with implications. A list of resources consulted in the preparation of this report is contained in Appendix 1 of Part 1.

The report is not designed as a scientific treatise on the substances and their potential health impact, but as a guide to Council offering sufficient clarity and explanation to elucidate the content and implications of use of the product, in terms of the original scientific literature.

STATUS OF DICHLORVOS IN AUSTRALIA

Binkill is described by the Australian Pesticides and Veterinary Medicine’s Authority (APVMA) as a home garden product, with a dichlorvos content of 80 g/kg and a naphthalene content of 800 g/kg, used in the control of flies and maggots in garbage bins. It was one of the first four products containing dichlorvos to be approved and registered for use by the APVMA and is still registered with the product code 47695.

In December 1996 the APVMA announced that it would be carrying out review of seven chemicals of concern, including dichlorvos, and produced a preliminary review document for public and institutional consideration and comment in June 2008. This is still open for consultation (APVMA, 2008). This concern was apparently born of growing international concern relating to the impact of a range of pesticide products on health and the environment, and the investigation, in response, of a range of pesticide products by the American Environmental Protection Agency (EPA).

In the report on preliminary findings from the APVMA (2008) a large number of practices involving application of liquid dichlorvos have been disapproved of, and advice has been given that they should be modified or discontinued. At present comments on these recommendations are being called for from the public and certain relevant scientific disciplines. It is probable that when the review is finalised legislative change may be sought to control some of these applications. Disapproval has been based more on an inability to adequately protect staff from the chemical using known approaches and available personal protective equipment (PPE), than on its extensive use in food products both for local use and for export from Australia.

In this regard, over 55% of dichlorvos use in Australia is for agricultural application with up to 10 000 tonnes of grain being treated daily for export and local use. Despite the extensive use of dichlorvos in many food production and storage industries, two Australian Total Diet Surveys in 2002 and 2003 respectively, performed under the strict control of the Food Standards Australia New Zealand (FSANZ), failed to detect the pesticide in any of the food

5 items surveyed although application to most of these had occurred (APVMA, 2008). This lack of residue makes dichlorvos exceptional among directly applied pesticides.

This lack of residue is partly due to dichlorvos’ volatility in comparison with the other organophosphate (OP) pesticides in common use. It has a vapour pressure of 145 mg/m3 at 20°C, with a boiling point of 140 ºC. It therefore has to be dissolved in a less volatile substance to prevent ready evaporation at room temperature, and as it is non-polar it is dissolved in other non-polar substances such as oil, long-chain alcohols, naphthalene and plastic resins, such as PVC resin.

Its properties of volatility and non-polar solubility give it advantages and disadvantages. Because it vaporises easily it can be used as a fumigant whereas other OP pesticides cannot. This gives it the useful property of penetrating stored grain and other material to reach insects which it also penetrates by dissolving in their fatty structures and reaching target sites in the arthropod nervous system. As a result it does not have to be sprayed onto surfaces like other OP pesticides, where a residue can remain to be potentially picked up by the hands of staff or to be ingested by the consumer. A disadvantage is that it can enter the human body by all three main exposure routes, inhalation, ingestion and contact, easily passing the cellular phospholipid barrier as a non-polar substance. It is also very penetrative, going into cracks and crevices and even dissolving in plastic material and structures from which it is then slowly released.

After fumigation using dichlorvos dissolved in a slow-release liquid it can remain in air pockets between structures and substances or is slowly released from non-polar substances in which the oil or alcohol base has dissolved. This presents a post-fumigation hazard and the APVMA advises a four-day vacancy with airing prior to occupation when dichlorvos liquid in solvent base has been used to fumigate indoor habitable spaces.

Once inside the human body its action presents a physiological paradox. It is extremely rapidly metabolised (broken down) its half life being an incredible 8 to 20 minutes (Leikin & Paloucek, 2008) so that repeated exposures do not present the same accumulation hazard noted with many other pesticides. It has also not been proven to cause cancer when ingested, inhaled or on contact, which is probably related not only to its properties but also to the high rate of metabolism already commented on. In the very short time it is in the body, however, it binds irreversibly with cholinesterase, preventing further nerve messages from crossing the small, fluid filled space between nerves and muscles throughout the body of many living things including humans, animals and insects. This binding is permanent, there is no antidote, and cure relies on waiting for further cholinesterase to be built up in the body, while the liver breaks down the pesticide. In the interim the patient is given life support in terms of improving blood supply to essential structures such as the heart, lungs and brain until the crisis is over.

While indoor use of liquid applications in the presence of personnel has received the harshest judgement in the APVMA report, the use of dichlorvos dissolved in plastic (PVC resin) strips was also extensively criticised on the basis of studies showing that where babies, young children and adults were exposed to strips containing more than 20% dichlorvos the safe margin of exposure was substantially exceeded (Cavagna et al., 1969; Cavagna et al., 1970).

The APVMA therefore refused to renew registration of such strips, although only one Austrian product will be effected by this action (APVMA, 2008). Two further problems

6 identified by the APVMA were the inability of the PVC resin to provide a controlled rate of release under the action of different daily temperatures, and the tendency for strips to start off by releasing high levels of the fumigant which then tails off over the intended usage period to a negligible level.

Binkill is similar to a pest strip in that a mechanism is provided for slow release of the fumigant pesticide vapour. The dichlorvos is, however, not dissolved in plastic resin but in solid naphthalene which itself liquefies with immediate evaporation to result in turn in the slow release of the pesticide. While the physical performance of Binkill or similar products was not identified in the APVMA report 2008, it is likely that the product would also suffer from variable performance under the action of time and temperature noted for the PVC resin strips.

The slow release agent, naphthalene, used in binkill is itself is a poisonous substance and insecticide, although the amount permitted in the air in the occupation setting (its safe exposure threshold), is 100 times higher than that for dichlorvos (Klaassen, 2007). While inhalation of the vapour in the concentrations found from the placement of a few mothballs in clothing is generally safe, some individuals may suffer acute attacks of haemolysis, where red cells break down and released protein substances, such as haemoglobin, can choke kidney structures resulting in change of urinary osmolarity with sometimes fatal results. Those affected in this way often have an inherited glucose-6-phosphate dehydrogenase (G6PD) deficiency, which is more common in persons of South continental descent than in others.

Young children are also known to be attracted to the smell of naphthalene which is a common cause of poisoning after mothballs have been sucked or swallowed (IPCS, 2000).

Part 2 of the report will consider the feasibility of some identified “hazards” occurring and the outcomes should this occur. For, example, it is conceivable that members of the public could start using Binkill indoors as the much trusted resin strips become no longer available, and that children attracted to the naphthalene odour might attempt to suck such devices, exposing themselves to the accompanying dichlorvos pesticide. A barrier to this exposure to be considered might be better labelling of the product which currently does not bear an instruction that it must only be used outdoors.

When removed from its sealed wrapping, Binkill consists of a ventilated plastic enclosure, described by Agspec Australia Pty Ltd. as a “tamper proof container”, which holds the naphthalene, dichlorvos and other ingredients in the proportion 80: 8: 12. The constituents of the remaining 12% is unknown, and while the formulation is proprietary information, Binkill need to be asked if they are prepared to reveal the nature of any chemicals which may be active in the remaining part, which will be included in activities for preparation of Part 2 of the report.

While pest strips, which are typically used indoors, received generally negative attention in the APVMA report which was well referenced to the international scientific literature, there was very little attention to naphthalene release products such as Binkill, which were dismissed with the comment “exposure via the use of the naphthalene/dichlorvos blocks is considered negligible, as they are only used outdoors”.

An extensive search of the literature by the toxicologist failed to detect any scientific studies of such products despite the fact that the basic concept of using naphthalene as a slow release product for dichlorvos in a protective container is not exclusive to Binkill.

While the assumption that the product results in negligible exposure if correctly used outdoors may be valid, the toxicologist believes that there may be circumstances under which misuse and therefore higher levels of human exposure could occur. These might include:

 the keeping of a wheelie bin fitted with one or more blocks indoors to capture food scraps where the vapour might escape into a kitchen or other living area.  use of a dumpster fitted with multiple blocks for sleeping purposes by vagrants who could be exposed continuously for 2-3 days were they intoxicated with alcohol or other narcotic drugs. This would be exacerbated by high ambient day temperatures with low humidity, or even higher temperatures which might be generated by the sun falling on a dark dumpster. Children might also enter a dumpster or wheelie bin for play purposes or to hide, as has been depicted in many videos and films, but this would be likely to result in much shorter exposure.  storage of a large number of Binkill packages in a store where the product might undergo release under certain conditions, such as dampness interfering with the packaging  potential misuse in an indoor rather than an outdoor setting to kill insects by residents who have been denied access to the pest control strips  tampering with the container of the product or accidental exposure in some other way by an adult or child.

The second part of the report will describe these and other potential hazards in terms of the probability of each occurring and an estimated consequence should this happen. Recommendations will be made to Council for putting barriers in place to reduce risk associate with any identified hazards to an acceptable level.

BACKGROUND TO THE ORGANOPHOSPHATE (OP) PESTICIDES

Dichlorvos is one of the organophosphorus-ester insecticides (OPs) of which there are more than 200 in existence. These are formulated into thousands of insecticide products which are used in preference to the organochlorine pesticides (OCs), such as DDT, dieldrin and toxaphene, which have been banned in much of the Western World including Australia in 1987. The reason for this ban is their slowness to break down in the environment and hence accumulation and amplification in ecological food chains, where they result in increased mortality and reduced biodiversity.

Because the OP pesticides are less ecologically harmful than the banned OCs, it must not be assumed they are not as toxic. Many are, in fact, more toxic than the OCs and because high level exposure can cause changes in the human body which are difficult to treat medically, they have to be presented to the public in ways which will avoid unacceptable exposure.

The news media sometimes emphasise the fact that the OPs were originally used as weapons of war by the Nazis after their development by scientists working under Gerhard Schrader in Germany in 1937. This is true of the earliest OPs, such as sarin, soman, and tabun but these compounds were crude, first generation poisons long since been banned for general use.

Sarin has, however, subsequently been illegally used in Iraq against Kurdish rebels in 1988, in Matsumoto, Japan, in 1994 (Morita, et al., 1995) and in the Tokyo subway attacks in 1995 (Nozaki, 1995). In the latter, sarin liquid was sealed in plastic bags wrapped in newspaper and subsequently placed on the floor of subway carriages when the sarin was released by puncturing with sharpened umbrellas. As a result of inhalation of fumes thirteen people died, fifty were severely injured and a thousand suffered from temporary vision problems. The motive for these fatal, disruptive and psychologically damaging attacks was religious and unclear.

The OPs in use today, however, are four generations of development away from those early chemicals, having undergone progressive improvement to decrease toxicity to mammals, increase toxicity to insects, and secure rapid break down after use.

The first OP pesticide released for commercial used was TEPP (tetraethylpyrophosphate) which was effective but broad- spectrum (very toxic to most forms of life, an undesirable characteristic in pesticides), and very unstable. After the poisoning of a number of florists who handled stems of flowers sprayed with the pesticide it was banned from use in many countries (Kent, 1998).

The next OP pesticides developed were parathion and then paraoxon, which both still had unacceptably high mammalian toxicity, resulting in poisonings and leading to further investigation and bannings.

The most recent group (40 to 45 years old), includes dichlorvos, acephate, temephos and trichlorphon. These pesticides are good insect killers with a low mammalian toxicity breaking down to acceptable levels after a relatively short period in the environment. Allusion by the media to the early, first generation products is therefore irrelevant given the large amount of chemical development and testing which has gone into these new products.

Dichlorvos has the advantage over the other third and fourth generation OP pesticides of being sufficiently volatile to be used as a fumigant, avoiding the necessity of applying a concentrated residual coating to garbage and surfaces of containers where it might later come in contact with garbage handlers or members of the public.

TOXICITY OF DICHLORVOS RELATIVE TO OTHER SUBSTANCES

An indication of relative toxicity of different substances is given by safe occupational exposure thresholds for substances in air. Here there is usually an assumption that the exposure to a substance will occur over a lifetime consisting of 8-hour work days and 40- hour work weeks, and that there will be a respiration rate based on moderately heavy labour (Klaassen, 2007).

There are two American organisations carrying out toxicological tests on a range of different laboratory animals, extrapolating the data to humans, and producing tabulated data which most countries, including Australia, base their own standards on. These are the American Conference of Government Industrial Hygienists (ACGIH) and the Occupational Safety and Health Administration (of America), who produce threshold limit values (TLVs) and permissible exposure limits (PELs), respectively

The ACGIH TLV for dichlorvos is 0.1 ppm, and the OSHA PEL is 1 mg/m3. The latter value was revised to this from 0.9 mg/m3 in 1993, but some of the Australian documentation has not yet been upgraded. Understanding these indices is best achieved by comparing values for dichlorvos with values for other substances as shown in the tables below. Table 1 lists substances less toxic than dichlorvos in air, whereas table 2 shows those more toxic than dichlorvos in air (Klaassen, 2007)

Table 1: Substances less toxic than dichlorvos in air (ranked from least to most hazardous)

Substance Limit Acetone 500 ppm Petrol 300 ppm Turpentine 100 ppm Nitrous oxide 50 ppm Toluene 50 ppm Acetic acid 10 ppm Chloroform 10 ppm Pyrethrum pesticide 5 ppm Sulphur dioxide 2 ppm Malathion pesticide 10 mg/m3 Chlorine 0.5 ppm

Table 2: Substances more toxic than dichlorvos in air (ranked from least to most hazardous)

Substance Limit Parathion pesticide 0.5 mg/m3 Diquat pesticide 0.5 mg/m3 Heptachlor pesticide 0.5 mg/m3 Nicotine 0.5 mg/m3 Chlordane pesticide 0.3 mg/m3 Dieldrin pesticide 0.25 mg/m3 Fenthion pesticide 0.2 mg/m3 Endrin pesticide 0.1 mg/m3 Fenofos pesticide 0.1 mg/m3 TEPP pesticide 0.05 mg/m3 Arsenic vapour 0.01 mg/m3

As shown in the above, dichlorvos is one of the safer pesticides in terms of airborne exposure in the occupational setting. It has the same PEL rating as DDT which was once blown into hair and clothing of 18 million returning soldiers and displaced people after WWII, apparently without adverse health effects (Stallybrass, 1946). DDT was, however, banned in Australia in 1987 following 25 years of reports of impact on wildlife, in particular bird populations, where thinning of eggshells and other reproductive effects had been noted, adjacent to areas where it had been used. Initially DDT was banned from general use, followed by most of the other organochlorine (OC) pesticides such as dieldrin, heptachlor and chlordane, on the grounds that they were unacceptably persistent and bioaccumulative in nature (Linda, 1997).

The OP pesticides are therefore substitution products for the more ecologically-damaging OC pesticides, being readily broken down, usually by hydrolysis; the chemical addition of water under the action of natural enzymes. Being one of the safer OP pesticides one must question which replacement product would be used in Australia, were it to be removed from widespread service in areas such as the fumigation of stored grain products.

While the above tables give a rough indication of relative toxicity of dichlorvos, comparisons in toxicology are always problematic as each chemical compound has its own highly specific set of physical and chemical properties which need careful consideration.

FORMS OF DICHLORVOS PESTICIDE IN USE

Because dichlorvos is highly volatile it is usually only available for general application in the following forms:  Dissolved in oily solutions  Suspended as emulsions (dissolved in oil, then suspended as a discontinuous phase in a water continuous phase)  As aerosol formulations (dissolved in oil and expelled with a propellant)  Impregnated in polyvinyl chloride resin (eg: the once popular “yellow resin” strips used to kill moths in cupboards in which clothing was stored.

 Dissolved in pellets of solidified oil, or soft wax with controlled vapour pressure characteristics for slow release.  Imbedded in volatile naphthalene, as in the case of Binkill, for slow release and to mask the sharp, garlic odour of dichlorvos.

WHY DICHLORVOS IS REGARDED AS SAFER THAN MANY OTHER PESTICIDES

 It is species specific to insects. Kent, in his Basics of Toxicology, regards it as “highly toxic” to insects, with “a low order of toxicity” to humans (Kent, 1998).

 It does not bioaccumulate in the human body. Toxic build up in human body fat on repeated exposure, which typifies OC and some OP pesticides does not occur (Leikin & Paloucek).

 Again relating to bioaccumulation, it could not be recovered in the milk of experimental animals even when they were given doses high enough to produce symptoms of severe poisoning (EXTOXNET, 1996).

 Dichlorvos is unusual among the OP pesticides in that it has a very high volatility (vapour pressure 145 mg/m3 at 20°C), causing rapid evaporation and dispersion by simple diffusion. A typical vapour pressure for other OPs is exhibited by parathion- methyl at 0.14 mg/m3 at 20°C.

 Its volatility allows it to be used as a fumigant rather than a surface treatment, like the other OP pesticides. In these other pesticides a surface layer is deposited on garbage and containers as a concentrated layer which can later come in contact with hands, clothing or food.

 Controlled use of a fumigant pesticide is preferable to the use of a liquid pesticide in environments where solvent release may result in drowsiness or the risk of fire hazard.

 Other pesticides have to be dissolved in a liquid phase (solvent) which may contain xylene or touluene with benzene as an impurity (Kent, 1998). Benzene is a confirmed human carcinogen (Class A1).

 Where dichlorvos does have to be used as a liquid, it dissolves well in non-polar substances but also to some extent in polar substances owing to its relatively short chain length. Washing away of spilt pesticide using soap and copious amounts of water, or preliminary washup of spills using hosing, is therefore possible (IPCS, 1986).

 The dangerous “intermediate syndrome” which has been observed with some OP pesticides during excessive occupational exposure potentially leading to respiratory paralysis and death, apparently does not occur with dichlorvos (Senanayake & Karalleide, 1987).

 Dichlorvos undergoes very rapid metabolism and excretion by mammals which have degrading enzymes in both tissues and blood plasma. Detoxification of ingested dichlorvos mainly takes place in the liver. When exposure of laboratory animals did not result in death, rapid and complete recovery occurred in most cases (EXTOXNET, 1996)

 Maximum residue levels (MRLs) have been established for a large range of foods, including grain directly sprayed with dichlorvos in silos. These are relatively easy to monitor and in the case of Australian grain product production and export are strictly applied (EXTOXNET, 1996).

 Despite extensive Australian use on foodstuffs two Australian Total Diet Surveys in 2002 and 2003 respectively, performed under the control of the Food Standards Australia New Zealand (FSANZ), failed to detect residual pesticide in any of the foods surveyed. The dietary exposure was therefore estimated to be zero. Exposure in drinking water is also considered to be negligible based on the results of drinking water testing (APVMA, 2008).

PRESENT USES IN AUSTRALIA

Dichlorvos is extensively used as one of the safer insecticides available in Australia. The present list of uses includes:

 moth, beetle and weevil control in granaries and grain handling equipment as fumigant or spray. This is the main Australian use, accounting for 55% of all agricultural applications, with up to 10 000 tonnes of grain treated in a day. Australian grain nevertheless complies with all local and international export requirements (APVMA, 2008).  spraying of stored potatoes  fogging of food crops  greenhouse insect control for ornamental crops  fogging of growing mushrooms  field control of leaf roller in avocados  fumigation of vegetable seedlings  fumigation of cut flowers  animal houses and pens, including cattle sheds, piggeries and stables  abattoir and meat works fumigation  winery fumigation food warehouse fumigation  mill fumigation  oral treatment of worms and bot fly larvae in horses by oral application  in-flight disinfestation of vectors (insect carriers) of human disease  household disinfestation of pests, in particular clothes moths  pet flea and tick collars  household pest strips (accounting for 15% of dichlorvos use in Australia)  public health surface sprays  insecticidal powders

APPLICATION METHODS WHICH MAY BE PROHIBITED IN AUSTRALIA

Table 3 lists some application methods which have been supported and others which may be discontinued when the final version of the APVMA report is published:

Table 3: Method of application, and preliminary APVMA recommendation:

Application Method APVMA recommendation

Method supported Manual treatment of grain storage Supported provided that operators do not containers (50 LD/CO2) enter the enclosed space during fumigation and that suitable PPE is worn Occasional treatment of farm machinery Supported with elbow length butyl rubber and eradication of wasp nests outdoors gloves, chemical clothing and a full face (1140 & 500 EC) respirator Direct injection into ant nests Supported with suitable PPE Application to bee and wasp nests (500 Supported with suitable PPE EC)

Method not supported Application as space spray (50 LD/CO2) Effective PPE not possible; practice should be discontinued Mixing and loading (1140 & 500 EC) Effective PPE not possible; practice should formulations and mechanical application to be discontinued grain Application of 500 EC as indoor surface Operator exposure too high and practice spray in houses should be discontinued. Application as indoor surface spray in Operator exposure too high and practice animal housing, milk and meat processing should be discontinued facilities and grain storage structures Application as indoor fog or mist (500 EC), The necessary operator controls cannot be in premises such as stables, piggeries, maintained and therefore this should be abattoirs, wineries, factories, stores, mills, discontinued warehouses, tobacco stores, warehouses, greenhouses and mushroom houses. Outdoor application to garbage dumps by Practice should cease unless relevant space spray, fog or mist exposure, work rate or handling data can support the practice “Wooden board method” (500 EC dripped Should be discontinued onto wooden board in stores and barns, to be evaporated with fans) Application by watering can (500 EC) Method not supported Crack and crevice treatment (500 EC) Method not supported Application by paint brush Should be discontinued Treatment of avocados Method not supported

FUTURE OF PVC RESIN STRIPS FOR SMALL SPACE FUMIGATION

In the APVMA review (2008) resin strips containing 20% dichlorvos for indoor small space fumigation performed particularly badly and registration will no longer be supported, with existing stocks to be sold out 2010. As these have some similarities with dichlorvos- naphthalene blocks, except that the latter are envisaged by the APVMA as being used only for outdoor small-space fumigation, the case which was found against the dichlorvos pesticide strips will be considered here.

In a number of studies of the human health impact of the strips as installed in terms of the packaging recommendations, which were in turn based on legislated requirement, no inhibition of plasma or red blood cell acetylcholinesterase activity occurred (Leary et al, 1974; Zavon & Kindel, 1966). Exaggerated exposure of 10 and 17 strips per room resulting in a dichlorvos concentration of 2.2 and 7.1 mg/m3 respectively caused inhibition of plasma cholinesterase activity in adult males, although red blood cell cholinesterase was not inhibited in the 10 strip study (APVMA, 2008).

Local risk assessment relating to the strips was, however, carried out by the Australian Pesticides and Veterinary Medicines Authority, based on an average air level of 0.05 mg/m3. In the report it was warned that levels generated by the strips would vary considerably under different temperatures in different parts of Australia and at different times. They assumed a worst case scenario of someone remaining in the room continuously, and a conservative case scenario of someone only returning to the room to sleep.

An average air concentration of 0.05 mg/m3 was assumed as complying with a safe exposure threshold (NOEL) of 0.02 mg of poison per kg body weight per day. When the doses which would actually be received by children under 1 year of age, children 1-12 years, adult males and females were computed, the resulting dose was found to exceed the permitted margin of exposure (MOE) for all groups (Cavagna et al., 1969; Cavagna et al., 1970).

The Australian Pesticides and Veterinary Medicines Authority interpreted these results by saying that while they did not consider that pest strips containing 20% dichlorvos for treating entire rooms would represent an acute or short-term risk to human health, chronic exposure calculations indicated an exceedence of safe limits for infants, children and adults, in terms of plasma and red blood cell cholinesterase inhibition. Because of this, it was concluded that registration of these types of pest strip could be no longer supported. It mentioned that the recommendation would have minimal Australian impact, only effecting a single product in at that stage (Sureguard Pest Strip Household Insecticide, registered with APVMA product code 45596).

There are few studies relating to direct skin contact with pest strips, though in one study repeated dermal exposure to PVC strips for 5 days failed to impact on plasma or red blood cell status (Zavon & Kindel, 1966).

In studies in other countries the strips have been found to contain between 15-35% dichlorvos (m/m) generating about 0.20 to 0.25 mg dichlorvos vapour per m3 of air over a 30 day period. A high variation in air concentration depending on the age of the strip and air temperature and humidity was noted (0.01 mg/m3 to 0.44mg/m3) making these products highly unreliable for slow release control for pesticide which requires a stable release process to remain effective. This is a characteristic which may well be shared in common with dichlorvos-

15 naphthalene blocks, although no research findings were available at the time of reporting (APVMA, 2008)

Temperature in the room plays a highly significant role in determining the amount released into the atmosphere. At high temperatures (34 ºC) a two fold higher concentration was found to occur in comparison to a lower temperature (20-22 ºC), with a higher rate of exhaustion of the block at the higher temperature (Elgar & Steer, 1972).

The concentration of vapour from the strips is further impacted by the nature of ventilation in the area, with trials in a number of countries showing a mean concentration of less than 0.1 mg/m3 in houses, which may be inadequate to kill the intended insects, such as moths (APVMA, 2008)

FUTURE OF DICHLORVOS/NAPHTHALENE BLOCKS FOR SMALL SPACE FUMIGATION

The APVMA has given tacit approval to the continued use of these blocks with the comment “exposure via the use of the naphthalene/dichlorvos blocks is considered negligible, as they are only used outdoors” (APVMA, 2008). An extensive search of the literature, however, failed to reveal any research relating to potential risk associated with such products. The term “outdoors” has also not been investigated and defined in the Australian context.

Given that the APVMA has not carried out further investigation, or restricted this product because of this expectation one would expect some warning that the product should only be used outdoors on the labelling, but this is not included on the external packaging for the Binkill product. This will be further investigated and suitable action recommended in Part 2 of the toxicology report.

As mentioned in the introduction, there are a range of possible hazardous scenarios which might impact on risk presented by use of Binkill, which will be included in Part 2 of the report. At this stage these include:

 misuse of the product through indoor use where it might constitute a health hazard on 24-hour exposure  the keeping of a wheelie bin fitted with one or more blocks indoors to capture food scraps where the vapour might escape into a kitchen or other living area.  use of a dumpster fitted with multiple blocks for sleeping purposes by vagrants who could be exposed continuously for 2-3 days were they intoxicated with alcohol or other narcotic drugs. This would be exacerbated by high ambient day temperatures with low humidity, or even higher temperatures which might be generated by the sun falling on a dark dumpster. Children might also enter a dumpster or wheelie bin for play purposes or to hide, as has been depicted in many videos and films, but this would be likely to result in much shorter duration exposure.  storage of a large number of Binkill packages in a store where the product might undergo release under certain conditions.  tampering with the container of the product or accidental exposure in some other way by an adult or child.  other exposure of children such as by sucking of the device.

PHYSIOLOGICAL ACTION OF DICHLORVOS

Dichlorvos, falls into the group of poisons known as “cholinesterase inhibitors”, of which there are two groups, the organophosphate (OP) compounds and the carbamate compounds. It is the esters of both groups which act as poisons. The OP esters, such as that contained in dichlorvos, poison in the following manner:

In the human body, the small, fluid-filled gap exists between the end of a nerve and the muscle to be activated in every part of the body. This is called the neuromuscular junction, and it must be bridged by a chemical compound released by the nerve, which diffuses acreoss the gap to reach the cell membrane of the muscle. The most common neurotransmitter substance in the body is called acetylcholine. When the acetylcholine has bridged the gap it attaches to receptor sites on the muscle membrane resulting in contraction. Following this the acetylcholine has done its job for the moment and is not wasted but is freed by a “breaker” enzyme called acetylcholinesterase (“cholinesterase”, for short) to drift away from the muscle membrane for recycling. The muscle has contracted once and has done its work.

OP pesticide (specifically the reactive OP-ester), binds permanently to this “breaker” enzyme and stops it from leaving the surface of the muscle for recycling. The acetylcholine stays attached to the muscle surface causing prolonged and unwanted contraction to continue, or for the muscle to carry out a series of weak and useless twitches referred to as “tetanus”.

It is for this reason that insects exposed to insecticides such as dichlorvos, malathion, parathion or chlorpyriphos lie on the floor twitching before finally critical muscles moving air and blood (they have a rudimentary heart) cease to work, and death results (McCance & Huether, 2009).

The same process takes place in humans although human buffering systems for pesticides are more advanced and extensive than those of insects leading to little or no ill-effect from an dose which would kill most insects. If sufficient poison is received, however, fatal effects will also result in humans.

It must be emphasised that the effected cholinesterase is permanently damaged in this process and that recovery relies on the production of new cholinesterase in the body, while the OP pesticide is broken down by the liver and other structures. Fortunately in the case of dichlorvos, this is a surprisingly rapid process compared to most other pesticides which share a similar mode of action.

While medical support is given following poisoning, it must be pointed out that this symptomatic in an attempt to keep the heart and other essential organs from shutting down. There is no antidote for the poisoned cholinesterase.

Following poisoning, the liver and certain other organs and tissues rapidly break down unreacted dichlorvos-ester by hydrolysis and it is removed from the body, 20 % as carbon dioxide by the lungs and 9% as urinary metabolites (Leikin & Paloucek, 2008). Its half life in the body is an astonishingly short 8 to 20 minutes, but in this time large quantities of cholinesterase can have been irreparably damaged. If contraction of certain critical muscles under nervous system control is severely inhibited in this physiological process (eg: heart and lungs), death can result (Klaassen, 2007). This makes acute, high level dose poisonings such as those occurring in attempted suicide particularly hazardous.

HEALTH OUTCOMES OF POISONING

While poisoning by inhalation or skin contact is the usual occupational scenario, ingestion in attempted suicides is a common route of exposure in the Australian agricultural community where access to farm poisons permits this approach. Less frequent causes of acute poisoning are inhalation or contact. Dichlorvos easily passes the phospholipid cellular barrier and being non-polar can diffuse through epithelium into the tissue fluids and blood, making it accessible by all three routes.

Poisoning usually results in widespread impact on the nervous system, with specific signs and symptoms as follows (Klaassen, 2007):

Signs and symptoms of acute poisoning

 Respiratory tract: Wheezing, running nose, coughing of fluid, tightness of chest, difficulty breathing, skin turns bluish, spasm of lungs, life threatening.  Cardiovascular system: Irregular heartbeat and pulse, paleness, increased blood pressure, possible heart failure, life threatening.  Central nervous system: Weakness, tiredness, drowsiness, fatigue, confusion, inability to concentrate possibly leading to accident, emotional disturbance, headache, pressures in head, may be early symptoms leading to unexpected verbal response or behaviour or an accident. Later unconsciousness with tremors and absence of reflexes, convulsions, life threatening.  Skeletal muscles: Facial and ocular twitching, loss of coordination possibly leading to an accident, restlessness, sensitivity to sound, muscle weakness with rigid or flaccid muscles, cramps, paralysis.  Eyes: Small, unchanging pupils, drooping eyelids, blurred vision, unreactive to light, bloodshot eyes and bloody tears.  Gastrointestinal tract: Nausea, vomiting, abdominal swelling and discomfort, cramps, diarrhoea or constipation,  Bladder: Increased or decreased urination frequency.

Analytical signs: Poisoning is usually diagnosed through signs and symptoms and through the recent history of the patient. Decreases in haemoglobin, red blood cells, and platelets with metabolic acidosis and severe hyperglycaemia are suggestive of poisoning.

Long term effects of acute poisoning

A number of suicidal poisonings with OPs including dichlorvos, where very large doses were involved, have resulted in long term central nervous system effects and debilitating muscle weakness, particularly in the legs. This localisation cannot be explained in terms of the cholinesterase inhibition mechanism alone and there are a number of hypotheses for its cause. The condition has been described in some texts as “organophosphate-induced delayed polyneuropathy (OPIDP)” (Lotti, 1992).

Chronic, low level poisoning

Flu-like symptoms have been recorded (Leikin & Paloucek, 2008)

Cancer causing potential

In Australia, successive health advisory committees have independently examined the carcinogenic (cancer causing) potential of dichlorvos on several occasions and have concluded that dichlorvos is unlikely to pose a carcinogenic risk to humans (APVMA, 2008).

The ACGIH (American Conference of Government Industrial Hygienists) has given dichlorvos an A4 classification implying that it is “not classifiable” at the present stage (Klaassen, 2007). This distinguishes it from other substances which are graded A3 (an animal carcinogen), A2 (a suspected human carcinogen) and A1 (a confirmed human carcinogen). It has not been given an A5 rating (not suspected as a worker carcinogen), probably because the evidence has so far has been inconclusive so the jury is “still out”. One has to keep in mind, however, that this is a very conservative jury and an A4 classification in pesticide product which has undergone 40 or so years of independent testing and to which vast numbers of lay people have been exposed without occurrence of cancer is generally to the credit of that product.

One of the probable reasons for this classification is the surprising speed at which the substance is metabolised in test animals making it difficult to achieve prolonged, widespread exposure to the required range of tissues and organs to comply with toxicological exposure requirements for laboratory animals.

Dichlorvos has received the intensive attention of the anti-pesticide lobby for the past 30 years which has put pressure on organisations such as the American EPA to fund exhaustive tests on the product. In 1981 the EPA considered a ban on 13 pesticides but the evidence against dichlorvos was inconclusive. In 1988 was subjected to intensive review but again a ban was not considered to be justified. In 1991 the EPA declared it to be a “possible carcinogen” requiring further investigation following mixed results relating to tumour production in toxicological tests. It must be emphasised that the term “possible carcinogen” as used by the EPA does not suggest that the substance is a likely carcinogen, but merely that it is a candidate for further testing. The term appears, however, to have been picked by the media and anti-pesticide lobby on occasions and misused. Because dichlorvos and cancer is such a topical issue, these seminal tests will be further discussed here:

In these tests rats were fed up to 25 mg/kg/day, and dogs fed up to 11 mg/kg/day orally for two years with no development of tumours. In another experiment, however, when mice were, however, fed 20 mg/kg/day in males and 40 mg/kg/day in females for 103 weeks (5 day per week exposure cycles) via stomach tube there was an increase of non-cancerous (benign) tumors in the stomach lining of both sexes. The same experiment repeated on rats using 4 and 8 mg/kg/day respectively, both doses producing increased incidence of leukaemia and benign tumours of the pancreas in male rats, with the higher dose also producing increase in benign lung tumours. In female rats there was an increase in tumours of the mammary gland. The final decision was that “evidence about the carcinogenicity of dichlorvos is inconclusive” (EXTOXNET, 1996).

Finally in 2006 the EPA restricted household use to garages, cupboards, attics and crawl spaces, and a total indoor ban is still under consideration.

Mutagenic effects

Mutagenicity implies the ability of the impact of a substance to be passed on to subsequent generations, despite the removal of exposure of new generations to that substance. This implies that the substance has in some way changed the genetic make up of the first individual and that the genes inherited by successive offspring have in some way been permanently changed. There are limited examples of true mutation in humans, probably because of the ability of effected human cells to be repaired or discarded, but the process is common in single cells, such as bacteria and cellular systems in lower order animals.

Because dichlorvos can bind to DNA there has been extensive testing for mutagenicity. While mutagenesis has been obtained in vitro (ie: in tests carried out using single human living cells outside the body, as in the Ames test), no mutagenicity has been detected in tests performed on living animals. This is possibly because of the rapid rate of metabolism and excretion of the chemical (EXTOXNET, 1996). A conclusion of an authoritative and extensive Australian investigation concluded that “it is unlikely to pose a genotoxic risk to humans” (APVMA, 2008).

Teratogenic (birth-defect producing) effects

Increase in birth defects is a very sensitive indicator of the potential impact of poisons on humans and ecosystems. Experiments involving prolonged exposure of rats and rabbits by ingestion and inhalation did not show that dichlorvos is teratogenic (Gallo and Lawryk, 1991; APVMA, 2008).

Toxicodynamics/kinetics

It is absorbed rapidly after having been taken in by ingestion, inhalation or skin contact, due to its non-polar property which allows it to pass the phospholipid cellular barrier. Its half life in the body is 8 to 20 minutes. 20 % is ultimately eliminated as carbon dioxide by the lungs and 9% as urinary metabolites (Leikin & Paloucek, 2008).

Synergisms

Malathion may increase the toxicity of dichlorvos.

Acceptable, Toxic and lethal oral doses An Acceptable Daily Intake (ADI) is 0.001 mg/kg body weight per day based on the rodent No-Observed-Effect-Level (NOEL) of 0.014 mg/kg body weight per day. In 2000 an Australian study recommended revision of the health value for drinking water from 0.001 to 0.007 mg/mL to reflect this, implying that the substance was safer in drinking water than was previously thought.

Toxic dose is 300 mg/kg and lethal dose is 400 mg/kg.

FIRST AID TREATMENT

In first aid treatment the different potential routes of exposure must be considered (Leikin & Paloucek, 2008):

 Poisoning by ingestion: Remove the contaminated clothing without skin contact by the first aider. Thoroughly wash with soap or preferably dishwashing detergent, any parts of the body onto which dichlorvos has been spilt, including hair and nails (soaps may contain creams which might assist the dichlorvos to pass the skin barrier). 5% bleach can be added to the water used for washing. Do not induce vomiting because of the potential for triggering or aggravating a respiratory crisis or changed mental state including coma. Simultaneously secure urgent medical attention.

 Poisoning by skin exposure: Remove contaminated clothing without skin contact by the first aider. Thoroughly wash with soap or preferably dishwashing detergent any parts of the body onto which dichlorvos has been spilt, including hair and nails. 5% bleach can be added to the water used for washing. Simultaneously secure urgent medical attention.

 Poisoning through the eye: Splashing into the eye represents a common route of poisoning because items are often being examined or looked at when accidents occur and because the eye has no protective covering of skin. The sclera (including the cornea) is a thin and therefore easily permeated membrane and the eyelids and other structures present a trap for fluids. Irrigation (washing) should be carried out with copious quantities of warm, clean water or saline. Simultaneously secure urgent medical attention.

Supportive therapy (provided by paramedic on site, in ambulance or emergency ward)

 Airway management, ventilatory assistance, humidified oxygen administration and close monitoring for sudden respiratory failure.

Clinical treatment

 Atropine (or glycopyrrolate where atropine is unavailable) and pralidoxime are regarded by some clinical toxicologists as antidotes although the existing damage done to the cholinesterase is irreversible and treatments essentially “buy time” while the poison is exhausted or metabolised, and while the body constructs new cholinesterase resources. Asoxime chloride or Hl-6 (an experimental oxime) has been experimentally successful in reactivating red blood cell cholinesterase.  Supportive treatment (fluid replacement and oxygen) and symptomatic treatment will also be needed with initial close surveillance in an intensive care setting (Klaassen, 2007; Lotti, 1991).

ENVIRONMENTAL TOXICITY: ANIMALS

 Aquatic life: Experiments on grass and sand shrimp, hermit crab mummichog, fathead minnow, bluegill, mosquito fish and American eels have shown measurable toxicity which is greatly increased by exposure of the chemical to UV light. As dichlorvos is light and not particularly soluble in water, it tends to be found in higher concentrations near the surface of the water, effecting pelagic (surface and shore) creatures, such as macroinvertebrates, more than benthic (bottom dwelling and breeding) creatures. Macroinvertebrates show high to very high sensitivity so biomonitoring with these species is a distinct possibility. It does not, however, appear to bioaccumulate in fish (Howard, 1991).  Birds: Dichlorvos has been found to be highly toxic to birds and this can present an intractable problem when agricultural spraying is intended (Kidd & James, 1991).  Bees: Dichlorvos is more toxic to insects than other forms of life and bees are no exception (Kidd & James, 1991).  Other animals: Research has shown that spraying of animal housing with dichlorvos with subsequent reintroduction of animals does not result in residues in animal tissues or products.

A large and exhaustive Australian Government study led to the conclusion that “the overall environmental risk from most uses of dichlorvos products in Australia is expected to be acceptable” (APVMA, 2008).

Binkill should not present a problem if used as per the packaging instructions in wheelie bins and should not accumulate in garbage given that its action will be as a fumigant.

Disposal of partially used containers by controlled tipping could, conceivably, result in the release of dichlorvos to the aquatic environment where there could be serious consequences. These and other issues will be considered in Part 2 of the risk assessment.

ENVIRONMENTAL TOXICITY: PLANTS

Plant life is generally not effected by presence of the pesticide (U.S. Public Health Service, 2010).

ENVIRONMENTAL FATE

 Soil and groundwater: Dichlorvos has low persistence in soil where half lives of 7 days have been measured. The method of break down is hydrolysis and biodegradation whereas volatilisation from soils is slow. Breakdown is pH dependent with rapid break down in alkaline soils slowing in acid soils. At pH 9.1 the half life is about 4.5 hours, whereas at pH1 the half-life is 50 hours. It does not adsorb to soil particles being non-polar and is therefore likely to contaminate groundwater. A spill was observed to penetrate the ground with 18% to 20% penetrating to a depth of 0.3 m in about 5 days (Augustijn-Beckers et al., 1994; Howard, 1991).  Water: It remains suspended in water and does not adsorb to sediments making removal through primary sewage treatment unlikely. It degrades fairly readily in the aquatic environment by hydrolysis, however, with a mean half-life of 4 days, although

this is highly pH dependent. Volatilisation from water is slow (Howard, 1991; U.S. Public Health Service, 2010).

IDENTIFIERS FOR DICHLORVOS

 Synonyms for dichlorvos are DDVP, 2,2-dichlorovinyl dimethyl phosphate, dimethyl dichlorovinyl phosphate, vapona, dichlorophos, dichlorovas.  The following schedules apply to Australian products containing dichlorvos: o Schedule 5 for products containing 20% or less dichlorvos and impregnated in plastic resin strips or in sustained release pellets. o Schedule 6 for products containing 50% or less of dichlorvos, except when in Schedule 5. o Schedule 7 for those containing more than 50%, except when included in Schedule 5 or 6.  USA CAS No.: 62-73-7  USA RTECS no.: TC0350000  Hazardous substance (Australian Government: NOHSC, 2004)  Dangerous good (Australian Government: DITRDLG, 2007)  Risk phrases: R21/22: Harmful in contact with skin and if swallowed, R43: May cause sensitisation by skin contact o Safety phrases: S2: Keep out of reach of children. o S24/25: Avoid contact with skin and eyes. o S37: Wear suitable gloves (Agspec, 2010)

PROPERTIES OF DICHLORVOS

Chemical properties (Ohkawa et al. (Eds.), 2007)

The chemical formula of dichlorvos is:

(CH3O)2POOCH=CCl2

Structurally, the chemical can be represented as follows:

The product is chemically stable unless mixed with flammable substances, such as xylene, toluene, alcohols and oils. In these cases the chemical properties of individual solvents must be taken into account.

Conditions to avoid are extreme heat, contact with strong alkalis, oxidisers and reducing agents. All organic material must be kept away from nitric acid, particularly in the presence of fuming sulphuric acid, because of potential explosive effects. The chemical must also be kept away from strong reducing agents.

Hazardous decomposition products are carbon monoxide and oxides of phosphorus (eg: phosphorous pentoxide, P2O5. Vapour would burn on incomplete ignition to produce black smoke.

Physical properties (OSHA, 2010)

 Molecular weight: 220.98  Boiling point at 20 mm Hg: 140 ºC  Specific gravity at 25 ºC: 1.42  Solubility: Slightly soluble in water and glycerol; soluble in kerosene, ethanol, chloroform and acetone. Miscible with alcohol, aromatic and chlorinated hydrocarbon solvents, aerosol propellants and most non-polar solvents.  Reactivity: Contact with water or an alkali causes fairly rapid hydrolisation (breakdown by the chemical addition of water).  Amber liquid with a slight garlic odour at airborne concentrations greater than 1 part per billion.  Because of its volatility (vapour pressure 145 mg/m3 at 20°C) it is typically dissolved in another less volatile compound (oil, resin, naphthalene or PVC plastic) so that slow release of the vapour or oil/dichlorvos mix will occur.  It attacks certain plastics, rubber and plasticised coatings. It is corrosive to iron and mild steel.

Fire risk

Non flammable but in fires releases toxic gases such as phosphorous pentoxide, dioxin and carbon monoxide. Fires should be fought from an upwind position by fire fighting professionals using water, dry chemicals or foam.

STORAGE OF DICHLORVOS

Products containing dichlorvos, such as Binkill, should be stored in a cool, dry, well- ventilated area in properly-labelled, sealed containers. It should be kept away from acid or alkaline gases or vapours which can break down the pesticide. Empty Binkill containers should not contain any of the volatile product and could be disposed of by placing in garbage bins for the usual tipping process.

SPILLS AND LEAKS

As the pesticide is dissolved in naphthalene, spills and leaks should not have to be considered. If Binkill packages are involved in a road accident, such as the spillage of a large 24 number with or without release of naphthalene blocks, the resultant material should be removed out of the sun to a cool place as soon as possible under the supervision of persons trained to deal with toxic material and stored until advice from a council environmental health unit, local fire department and the manufacturer is be sought. Water should not be applied to the product if possible as the product is very slightly soluble in water and this might carry it into a waterway where wildlife could be damaged. In this regard it should be kept in mind that it is particularly soluble in non-polar solvents and may be removed from the site via spilt petrol, diesel, oil or kerosene.

Where fire is occurring the lesser of the two evils might be to apply water to reduce the opportunity for the product being incinerated which would release a range of toxic combustion products.

NAPHTHALENE

Binkill consists 800 g/kg of Naphthalene which is likely to have been added by the manufacturer in terms of the proprietary formulation for the following reasons:

 a slow release agent to control the release of the volatile dichlorvos  waterproofing agent in bins where condensate is likely to form  deodorising agent (dichlorvos has a sight garlic odour)  insecticide fumigant properties, although not synergistic with dichlorvos  insect repellent properties

The IUPAC name for naphthalene is bicyclo[4.4.0]deca-1,3,5,7,9-pentene). It is the substance also contained in urinal deodorant blocks and mothballs.

SOURCES AND QUALITIES

It is chiefly a petroleum product and occurs naturally in many tarry compounds. Smokers inhale substantial amounts in cigarette smoke, and while it is classified A4 (unclassifiable as a carcinogen) it produces a range of other health effects such as red blood cell suppression and eye cataracts. These are common conditions in cigarette smokers and there may be a link with naphthalene (Klaassen, 2007). When administered to mice it produces highly specific lesions in the bronchioles caused by tissue destruction.

EXPOSURE AND HEALTH EFFECTS

With a TLV of 10 ppm., the safe exposure level for naphthalene vapour is about 100 times higher than that for dichlorvos, making it by far the safer of the two constituents of Binkill.

It has, however, a number of very specific and unpleasant health consequences on ingestion (one mothball is enough to produce many of the symptoms, even death in some individuals) and can also be absorbed through the skin. Accidental ingestion of one block of Binkill would probably produce many of the symptoms in conjunction with the symptoms of dichlorvos poisoning.

It needs special mention that the blood disorder glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency), which is more common in individuals of African, Middle- Eastern and South Asian males, can be triggered by naphthalene. G6PD deficiency is the most common human enzyme defect, being present in more than 400 million people worldwide (Cappellini & Fiorelli, 2008)

Acute exposure effects:

Toxic effects vary considerably from adult to adult. A dose of 6 grams has been shown to produce severe toxicity in some cases and no toxicity in others. Mean lethal dose is thought to lie between 5 and 15 g (Gosselin et al., 1984).

Inhalation response:

Inhalation in the industrial setting is rare, but might be a risk factor with Binkill, were persons to be accidentally exposed to the product as discussed earlier. Opportunities for such hazards will be discussed in Part 2 of the toxicology report. Ant exposure would be seriously aggravated by the presence of the inherited blood disorder, G6PD deficiency.

The typical result of exposure by excessive inhalation in any individual would be headache, confusion, excitement, nausea, vomiting and sweating. There may be urine cessation, blood in the urine or an acute haemolytic anaemia in some individuals with genetic conditions, such as G6PD deficiency. ).

Inhalation reactions are most serious in infants. Valaes et al (1963) have reported a case where naphthalene inhalation occurred in 21 infants. Eight developed kernicterus (a serious form of jaundice of the newborn characterized by very high levels of unconjugated bilirubin in the blood and by yellow staining and degenerative lesions in the cerebral gray matter), while two died.

Ingestion results in vomiting, drowsiness, fever, headache, restlessness, change in mental state, seizures, coma, signs of blood pigment in urine (black), from high doses. In rare cases, liver damage occurs (Leikin, 2008).

The use of Binkill as an intoxicating inhalant based on the naphthalene content but with subsequent exposure to dichlorvos is unlikely, but not impossible. There are many recorded events of mothball abuse, principally by inhalation (Weintraub et al., 2000; Leiken 2008), and children have been known by the toxicologist to sniff naphthalene for its aroma.

Haemolytic anaemia:

Naphthalene occupies a special place in toxicology alongside benzene, lead, methylene chloride and nitrobenzene in that it is capable of destroying red blood cells. It does this by breaking down under the action of oxygen in the blood to α-naphthol and interfering with cell membrane integrity and ion balance. Cell fragility results with inability to maintain intracellular functions, and cell death results (Kent, 1998).

An outcome may be reduction in the number of red blood cells and hence the oxygen carrying capacity of the blood in chronic exposure. This is recognised as anaemia. Oxygen sensitive tissues such as the heart and brain respond first through an interaction resulting in arrhythmias (lack of expected heart rhythm with reduced cardiac output).

Initial symptoms may be shortness of breath, pale skin and fatigue.

Haemoglobinuria

This is an outcome of haemolytic anaemia as described above, where haemoglobin liberated from damaged red cells is precipitated in the renal tubules which subsequently become blocked. Hepatic necrosis can occur. This is most likely to occur in existing cases of the hereditary condition, glucose-6-phosphate dehydrogenase deficiency disease (G6PD deficiency). Other predisposing conditions are sickle cell anaemia and sickle cell trait (IPCS, 2000). Newborn infants are also more sensitive than others to the toxic effects.

Eye cataracts:

A number of pesticides (naphthalene, diquat and heptachlor) can cause cataracts when airborne of direct exposure causes changes in lens proteins with resultant cloudy swelling and ultimately degeneration and necrosis (cellular death). Accidental, high level, eye exposure to naphthalene (dust from solid naphthalene) causes cortical cataracts and retinal degeneration (Grant, 1986).

Immunotoxicity:

No evidence for suggested immunotoxicity exists, despite prolonged exposure (Shopp et al., 1984). This may be due to the low level of metabolites generated in the liver which subsequently migrate to the spleen.

Sensitivity response on contact:

Naphthalene in contact with the skin causes irritation and sensitization dermatitis, which clears spontaneously when contact ceases. Absorption may be enhanced by cosmetic or skin oils. There have been cases of children developing sensitization dermatitis when dressed in clothing stored with moth balls (Schafer, 1951). This is an unlikely scenario in the case of Binkill where the naphthalene is contained in a protective holder so that the handler is very unlikely to make direct contact with the product.

Ingestion:

This is of greatest danger to children given that a fatal adult dose would be 5 to 15 grams, whereas in children a reported dose of 2 g has been fatal. This probably is a result of rapid absorption, and an inability to conjugate the substance and its metabolites rapidly in the liver (Driesbach & Robertoson, 1987).

Ingestion might conceivably occur if the anti-tamper holder was chewed or sucked by an infant or young child. In this case dichlorvos poisoning would be the main concern but a poisons unit should also be advised of the naphthalene content. This would be more likely to occur if the product was incorrectly used indoors or insecurely stored.

Children appear to be attracted to the aroma of naphthalene and there are numerous cases of children being poisoned by sucking or chewing mothballs (Chun et al., 1998; Hayes, 1982; Santucci, Shah, 2000). It is not beyond belief, therefore, that a child might try to suck on Binkill on account of the aroma, although the anti-tamper holder and relatively large size of the product would probably make removal of the contents, even by salivation followed by re- ingestion of saliva, difficult. If used as directed a small child should find it difficult to achieve access, but access to the packed product might be possible if the product was not carefully stored. The packaging does have a warning to this effect, but there is no warning about using the product exclusively outdoors.

Ingestion of even small amounts of naphthalene would result in abdominal cramps with nausea, vomiting and diarrhoea. There would be bladder irritation. The person might have a headache, confusion, listlessness and profuse sweating.

Where a larger quantity was ingested there might be passage of brown or black urine with or without albumin or casts suggestive of kidney damage. Later convulsions and coma associated with severe renal failure might occur, resulting in death (IPCS, 2000)

Special risks: pregnancy.

Transplacental transfer of naphthalene and its oxidation products are possible. Infants of mothers who abused naphthalene (sucking mothballs) were born with haemolytic anaemia and jaundice. The clinical record shows, however, that both mothers and children in these unusual cases recovered (Anziulewicz et al., 1959; Hayes, 1982).

MODE OF ACTION

Ingestion results in the formation of an epoxide metabolite which is probably responsible for the observed haemolysis (Leikin & Paloucek, 2008). Haemolysis in G6PD deficient individuals is probably due to instability of erythrocyte glutathione.

Hepatic necrosis can occur from prolonged exposure aggravating removal of the substance and its metabolites. Toxicity may be increased in the newborn because of foetal liver inability to conjugate both naphthalene and bilirubin leading to icterus (jaundice) (IPCS, 2000)

Occular toxicity probably occurs through the presence of oxygen reactive species (ORS) reacting with lipid and protein and resulting in corneal and lens opacity.

TOXICODYNAMICS/KINETICS

Poisoning by inhalation of a high quantity is rapid. It is possible that substantial amounts could be released in a dumpster on a hot day to produce acute poisoning in a vagrant seeking shelter in the dumpster, particularly if that individual was already suffering from a blood disorder such as G6PD deficiency (author’s opinion). Opportunities for this will be discussed further in Part 2 of the report.

Dermal absorption is enhanced by the presence of oil on the skin.

Metabolism is carried out by the liver, and elimination is fairly slow via the kidneys (about 2 weeks), so kidney disease will enhance toxic effects.

Unlike dichlorvos, on repeated exposures it can accumulate in body fats

FIRST AID

In all cases medical advice should be secured.

For skin contact, prolonged (20 minute) washing with running water is required but ointments, treatments or even soaps containing creams should be avoided because naphthalene is a non-polar substance which will dissolve in cream then vanish through the skin entering the lymphatics venous blood.

For ingestion, vomiting can be normally induced for up to two hours, but would have to be avoided in the case of a Binkill block because the dichlorvos can produce simultaneous respiratory muscle effects which could result in choking and airway obstruction. Milk or fatty meals should be avoided for at least half a day to reduce absorption with fat content.

Naphthalene blown as powder or rubbed into the eye may be absorbed, causing cataract formation and should therefore be washed with copious amounts of water, preferably warm saline, immediately (Leikin, 2008).

Antidote is methylene blue.

ECOLOGICAL EFFECTS

Naphthalene is one of a number of polycyclic aromatic hydrocarbons (PAHs), including anthracene, pyrene and benzo(a)pyrene, known to produce acute toxicity with biodiversity reduction in aquatic environments. Macroinvertebrates, such as various aquatic and flying insect larvae, are known to be particularly effected. This can have serious impacts on the survival of higher animals such as amphibia (including frogs) and fish.

For this reason any unused or incompletely used Bankill blocks could not be disposed of by placing in garbage bins or by flushing with water destined for the waste water system.

PROPERTIES OF NAPHTHALENE

Chemical properties (Ohkawa et al. (Eds.), 2007)

The IUPAC nomenclature of naphthalene is bicyclo[4.4.0]deca-1,3,5,7,9-pentene, with chemical formula of C10H8

Structurally, the chemical can be represented as follows, indicating two, linked benzene rings:

Physical properties (IPCS, 2000)

It is a white solid formed of fused crystals, with a smooth, oily surface appearance. Because of its relatively short chain length it is fairly soluble in water, more soluble in alcohol and very soluble in ether.

Fire risk

It is flammable with a flash point of 79 ºC suggesting the need for care in selection of a storage site.

REFERENCES

Agspec, 2010. Material safety data sheet, Agspec, Mt. Gambier, Australia.

Anziulewicz JA, Herman JD, Chiarulli EE, 1959. Transplacental naphthalene poisoning. American Journal of Obstetrics and Gynaecology, 78, 519-521.

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APPENDIX 1: DATA BASES REVIEWED

List of data bases searched for this review:

TOXNET (Toxicology Data Network) HSDB (Hazardous Substances Data Bank) IRIS (Integrated Risk Information System) GENE-TOX CCRIS (Chemical Carcinogenesis Research Information Systems) TRI (Toxic Release Inventory) TOXLINE EMIC and DART/ETIC (Developmental and reproductive toxicology) SIS (Specialist Information Services) of NLM (National Library of Medicine) EXTOXNET (Extension Toxicology Network) IPCS-INCHEM (International Program on Chemical Safety of WHO) IARC of WHO (International Agency for Research on Cancer) United Nations Environment Program (UNEP) Chemicals HSFS (Hazardous Substance Fact Sheets) NSW DEC information (Department of Environment and Climate Change web site) US EPA (Subsidiary sites ECOTOX and EPA Office of Pesticides Programs). ATSDR (Agency for Toxic Substances and Disease) SOLVEDB NTP (National Toxicology Program Database) CCOHS (Canadian Centre for Occupational Health and Safety) NIOSH (National Institute of Occupational Safety and Health US). NIOSH-IDLH (Immediately Dangerous Life/Health), including:  NIOSH-DOE (Department of Energy)  OSHAPEL (information on Permissible Exposure Limits) CAS RN (Chemical Abstracts Service Registry Number) ChemIDplus Chemfinder APVMA (Australian Pesticides and Veterinary Authority, and subsidiaries) SCOPUS (Scientific journal abstract and citation data base) Science Direct (Elsevier scientific journal abstract and citation data base)

TOXICOLOGY REPORT ON

BINKILL GARBAGE BIN FUMIGATION PRODUCT

FOR

WASTE AND COMMUNITY PROTECTION

PENRITH COUNCIL

PART 2: HEALTH RISK ASSESSMENT: BINKILL USE AND PENRITH CITY COUNCIL

TOXICOLOGIST: CHRIS DERRY UNIVERSITY OF WESTERN SYDNEY JUNE 2010

INDEX

SECTION PAGE Sections of the report for executive attention 3 The risk assessment brief 3 Positioning risk assessment in a risk management framework 3 Weighing up the hazards: pesticide use versus fly breeding 4 Need for fly control in Penrith 8 The problem of resistance to insecticides 9 Hazard identification relating to Binkill use in Penrith 11 Risk estimation theory applied in this assessment 19 Raw data 21 Ranked risks 21 Associated uncertainties 22 Conclusions 24 Recommendations to Council 27 References 29

APPENDIX A 31

TABLES PAGE Table 1: Identified potential hazards relating to Binkill use in Penrith, with reasons 12-18 for their inclusion, and contributory factors Table 2: Table for the estimation of probability value (p) for each potential hazard 20

Table 3: Table for the estimation of consequence value (c) for each potential hazard 21

Table 4: Table for the estimation of uncertainty (u) for each of the assigned values 22

Table 5: Potentially hazardous events ranked in order of priority, with calculated 24 risk values and estimated uncertainty indices

FIGURES PAGE Fig. 1: Cyclic risk management framework for safe Binkill use in Penrith 4

Figure2: Binkill box, plastic envelope and device containing dichlorvos/naphthalene 25 block Figure 3: Binkill plastic envelope showing dichlorvos/naphthalene chips outside the 26 dispenser in the envelope adjacent to the V-notch for opening

SECTIONS OF THE REPORT FOR EXECUTIVE ATTENTION

While no executive summary of the report is provided it is suggested that those who want to read the salient conclusions and recommendations refer to the following:

 The table entitled: Potentially hazardous events ranked in order of priority, with calculated risk values and estimated uncertainty indices (table 5, page 23)

 The section entitled: Conclusions on pages 24 to 27

 The section entitled: Recommendations to Council, on pages 27 to 28.

THE RISK ASSESSMENT BRIEF

The toxicologist’s brief concerned the carrying out of a health risk assessment of Penrith City Council’s potential engagement in the storage, distribution and recommended use of the pesticide product Binkill in the Penrith Council Area, with the aim of securing safe and effective control of flies and their immature forms while minimising risk to the public through the use of the product to an acceptable level.

The toxicology brief forms part of a Penrith Council’s Waste and Community Protection strategy for exercising Duty of Care relating to the health of residents, visitors, staff and others in the Penrith Council Area while applying an environmentally responsible approach towards the recycling of green waste and food products as compost.

POSITIONING RISK ASSESSMENT IN A RISK MANAGEMENT FRAMEWORK

Risk assessment is defined by Standards Australia/Standards New Zealand (2009) as the “overall process of risk identification, risk analysis and risk evaluation”.

Risk identification, often referred to as “hazard identification”, is a qualitative process involving “finding, recognizing and describing risks”, whereas risk analysis is a “process to comprehend the nature of risk and to determine the level of risk”. This implies a quantitative process, and one in which risks are ranked to enable prioritisation for risk intervention. Risk evaluation is the “process of comparing the results of risk analysis with risk criteria to determine whether the risk and/or its magnitude is acceptable or tolerable”.

Risk management includes “coordinated activities to direct and control and organisation with regard to risk”. This takes place within a risk management framework, which is defined as a “set of components that provide the foundations and organisational arrangements for designing, implementing, monitoring, reviewing and continually improving risk management throughout the organisation” (Standards Australia/Standards New Zealand, 2009).

A risk management framework developed at UWS (Derry et al., 2006, Derry & Attwater, 2006) is shown in Fig. 1. This model has been assumed as a base model for risk management in the Penrith area during the investigation and the construction of the toxicology report.

Hazard identification

Intervention Risk assessment assessment

Risk communication

Policy Policy implementation development

Fig. 1: Cyclic risk management framework for safe Binkill use in Penrith

WEIGHING UP THE HAZARDS: PESTICIDE USE VERSUS FLY BREEDING

The potential risks associated with the use of pesticide in fly control must be weighed against the potential health hazards of pests with potential to be encountered during the collection combined green and food waste in Penrith.

In the case of green waste and household food scraps the two main pests of concern are rodents and flies. While rodent control is relatively easily effected by keeping bins closed, fly control is more complex. This is because flies are mobile, virtually ubiquitous in urban settings and not easily noticed in their activities aimed at gaining access to foods for sustenance and reproductive purposes. They also present problems such as the rapid onset of resistance to pesticides when on product is over-used.

Fly infestation considerations

Flies have potential to infest bin waste in two ways:

 By the laying of fertilised eggs (oviparity) or the direct deposition from the fly’s body of active larvae (viviparity), on putrescible green and food waste prior to its

introduction to the bin. This area is largely outside the control of the Council, other than by educating the public in safe food protection practice, and in fly control in and around the home.

 By the entry of the adult fly to the bin through a poorly fitting lid after which oviparity or viviparity is carried out. Council can address this issue by practicing quality control in the purchasing of bins, through insisting on replacement when damaged bins are identified, by educating the public on keeping the bins closed, and by using the sealable refuse containers (eg: biodegradable bags).

If the contents of the bin are removed to a controlled composting plant or controlled tip before the life cycle of the fly (from egg or larva to pupal stage and then adult) is completed, then the life cycle will not have been completed and it unlikely that the bins will act as a souce of adult flies populating an area.

If the contents of the bin are not removed, however, within the minimum life cycle duration, then the fly can complete its cycle in the bin and adults may emerge through a poorly fitting bin lid, or when the bin is opened to add more waste.

Fly control challenges

While physical control control fly breeding may seem like a simple process to the lay public (ie: removing the waste within the time period taken for the life cycle of the fly), it is complicated by the fact that garbage removal services must be highly predictable events, in order that the public can present their waste for removal at set times and receive a service with planned routine and contained costs. On the other hand, completion of the life cycle of flies is a highly variable process, depending on a range of factors, including (Brodbeck, 1969; Eldridge & Edman, 2000):

 the species and sometimes variety of fly.  the ambient (atmospheric) temperature  the ambient humidity  the temperature which might arise in the bin which is in turn dependent on factors like bin size, colour, exposure to sun, etc.  the temperature of the refuse due to its ongoing bacterial composition.  the nature of the continuously decomposing matter in the bin and its ability to provide for the food needs of maggots  the texture of the matter in the bin in allowing ready migration for the stages of the fly to zones of different temperature and texture  the ambient humidity  the moisture content of the putrescible material  the presence of natural or added inhibitory substances (eg: pesticide) in the bin

Flies of potential significance in Penrith

In NSW there are a number of flies which might require control, and which determine the type of insecticide which should be used and the control procedure (Eldridge & Edman, 2000; Hadlington & Johnston, 1982):

 The “common housefly” which is the ubiquitous Musca domestica, of family Muscidae, with a number of local varieties. This common fly has one of the shortest life cycles, which could be taken as about one week under optimal breeding conditions, but which is typically 8-10 days and could be considerably longer in cool weather  The “blow fly” which lays eggs or deposits larvae in food high in nitrogen and amino acids, including faeces, raw meat and fish, and other putrefying material. At least two genera (Amenia and Metallea) of the family Calliphoridae share this name in Australia, and there are a number of different species in each. Some species, such as the “snail parasite blow fly” (Amenia imperialis) enjoy some lay recognition.  the “Oriental latrine fly”, Chrysoma megacephala of family Calliphoridae

Flies as vectors of disease

The disease-transmitting potential of flies, and in particular the common housefly, should not be underestimated. In this regard, the housefly has several characteristics which make it an important vector of a wide range of human gastrointestinal and other diseases (Brodbeck, 1969; Eldridge & Edman; Crossley & Lane, 1995):

 It is synanthropic, living in the association of humans and domesticated animals does not generally survive where humans are not found.

 The female needs both complex protein (such as partially digested meat in human faeces, or cooked meat) and simple carbohydrate (such as sugar or simple grain starches) for egg production following mating. The fly will therefore land on substances such as blood and faecal matter and subsequently items such as, bread, cake icing and table sugar as part of the same meal.

 The fly has claws, and body and leg hairs which trap contaminated material and transmit it to sound food.

 Flies cannot eat solids so regurgitate part of the stomach contents onto dry foods like sugar. The fly mixes this with the food by stamping in the vomit and walking in circles until some of the food dissolves. After this the fly sucks up the food through a sponge like structure around its proboscis called the haustellum. For this reason the house fly has been described as a “winged sponge” (Cirillo, 2006). This process may be repeated many times on many sites on many food items in a single feed. In this way the flies stomach, body hairs, claws and haustellum have potential to act as vehicles for the physical transmission of a wide range of bacteria, viruses, protozoa and the eggs of parasitic worms from human and animal waste matter to clean food.

 The house fly’s life cycle is highly temperature dependent, being 10 to 14 days in temperate areas but possibly down to 7 days under hot conditions which might apply in summer in a wheelie bin. The cycle often starts, however, before refuse is placed in the bin when flies lay eggs on apparently innocuous material in kitchens or elsewhere, which is subsequently placed in the bin 2-3 days later. For this reason unless garbage removal takes place on a bi-weekly basis in hot climates, or where bins are likely to be stored in the sun, flies will breed out to adult forms in the bin. In cooler climates and where bins are not stored in the sun, weekly removal is advisable. 42

 95% of flies from a single brood stay within 3 km radius of their release point so that repeated contamination of food from a single source by a number of flies may occur. On the other hand a few individuals may travel as far as 20 km, where new infestations may be started.

 House flies are one of the very few fly types that purposefully enter dark openings in human structures. This brings them into contact with human food and aids dispersion by human vehicles.

 While pathogens do not multiply in the fly, they are physically stored in the stomach and on external structures such as claws, hairs and the haustellum.

Potential fly-borne diseases in Penrith

Flies have been shown to carry over 100 different pathogenic (disease causing) organisms, although the ones transmitted in any specific area would depend on the local disease prevalence in that population.

Extrapolating from the literature and epidemiological data, diseases with potential to be transmitted in Penrith are listed below (Brodbeck, 1969; Eldridge & Edman, 2000, Fetene & Worku, 2009; Getachew et al., 2007). This risk would be increased by the presence of material likely to contain bacteria in the garbage bin, such as faecal matter from napkins, dogs droppings or spent cat litter, blood from sanitary towels, vomitus, bandaging which has come in contact with an infected wound, etc.:

 β-haemolytic group A streptococcal infections, including streptococcal pharyngitis (strep throat), which can progress to rheumatic fever with potential to effect the joints and heart valves.

 β-haemolytic group B streptococcal infections, including pneumonia and meningitis of the neonate and elderly, which can progress to systemic bacteraemia; and where personal undergarments have been infected by flies, colonisation of the female reproductive tract with possible infection, or in the case of pregnancy, premature rupture of membranes with transplacental transmission to the unborn infant.

 Infection of wounds with Staphylococcus aureus, some varieties of which are methicillin resistant giving rise to almost untreatable “golden staph” wound infections. Methicillin resistant Staphylococcus aureus (MRSA), which now routinely causes fatal cross-infections in Australian hospitals, has been isolated from flies collected near confined poultry feeding operations in the USA, where poultry are fed antibiotics to enhance growth. A fly settling on a open wound could easily transmit this organism to a human (Graham et al., 2009)

 Fatal and untreatable diarrhoea in immunocompromised individuals by vancomycin- resistant enterococcus (VRE) also isolated in flies near confined poultry feeding operations. These bacteria have an ability to pass resistant genes on to other bacteria causing healthy individuals to become colonised by new types of resistant bacteria (Graham et al., 2009).

 Bacillary dysentery (shigellosis) which might be imported by infected individuals, or for which some apparently healthy Australians are symptomless carriers.

 Cryptosporidiosis caused by Cryptosporidium parvum, for which some Australians and domestic animals are symptomless carriers.

 Giardiasis caused by Giardia lamblia, for which some Australians and their domestic animals are symptomless carriers.

 Infantile diarrhoea through the transmission of enteropathogenic forms of Escherichia coli which can be fatal, particularly if in combination with poor nutrition and immunosuppressive conditions such as measles or influenza.

 Although rare, the direct infestation of live human tissues with the larvae of house flies has occurred, producing subcutaneous myiasis. In India fly eggs hatched between the uncleaned teeth of a child and larvae burrowed into the roof of the mouth and sinuses where they grew to a considerable size before being surgically removed by incision and forceps (Dogra & Mahajan, 2009).

 Threadworm infestation (Enterobius vermicularis), particularly of children.

 Salmonellosis food infection (Salmonella typhimurium and Salmonella enteritidis), which can lead to serious secondary infections.

 Staphylococcal food poisoning (Staphylococcus aureus)

 Clostridial food poisoning (Clostridium perfringens).

 Bacillus cereus food poisoning

 A wide range of conditions which might be imported by migrants with a limited understanding of urban hygiene conditions and infrastructure, and transmitted to susceptible Penrith residents. For example, amoebic dysentery caused by Entamoeba histolytica, and worm infestations such as roundworm (Ascaris lumbricoides), Whipworm (Trichuris trichiura), hookworm (Ancylostoma duodenale and Necator americanus) and pinworm (Strongyloides stercoralis). The most serious, however, would be typhoid fever (Salmonella typhi) which has a very unpredictable carrier state and for which migrants are not specifically tested. Many texts suggest that cholera could be imported and spread by flies but this is very unlikely as the infectious dose is probably too large to be discharged in one fly feed (1x106 to 1x108 viable organisms).

NEED FOR FLY CONTROL IN PENRITH

Houseflies alone carry a wide spectrum of dangerous diseases which could be transmitted from infectious material in refuse bins, or from infected food material in green waste bins, to human hosts. For this reason any situation which has been observed to give rise to fly breeding should be controlled as a matter of urgency.

In a complex urban setting such as Penrith this should involve a multiple-barrier approach. The use of a well-tried and proven pesticide with potential to be used safely in an outdoor setting, such as dichlorvos, is likely to prove an important part of such approach.

THE PROBLEM OF RESISTANCE TO INSECTICIDES

Houseflies and their immature forms develop ready resistance to continuous use of a single insecticide, including dichlorvos (Acevedo & Toloza, 2009; Eldridge & Edman, 2000; Price, 1988; Srinivasan et al., 2008; Künast C, 1980).

Insecticide resistance is the ability of insects to adapt to an insecticide so that they are no longer killed by it, or so that the killing power of the insecticide is seriously reduced. Almost all insects have this ability as an expression of artificial selection, and local or field resistance to a pesticide used liberally and repeatedly in a specific area is more the rule than the exception.

This necessitates the use of increasing concentrations of the pesticide is used, which may not be practical in terms of health, economic or application considerations, or the use in rotation of a number of chemically different insecticides.

The process of insect resistance involves the death of most members of a population, after which a few mutant strains with resistance to the pesticide breed up to take their place. They may even have ability to use the pesticide as one of their food sources. This resistant population explosion is also supported by the fact that in settings where insecticides are regularly used, predatory species (such as spiders and wasps) are simultaneously destroyed. The use of “eco friendly” pesticide application strategies which target the pest species while allowing other species to survive is therefore of importance.

Given the history of dichlorvos in readily producing resistance in house flies and other insect populations (apart from the above references there are many other papers describing this in both field and laboratory settings), it can be anticipated that should Binkill be too widely used its effectiveness of Binkill would wane over a number of months and it may even become ineffective after a period of more prolonged use.

In this regard the author has experience of OP pesticide use on open garbage pits in an indigenous settlement where resistance was produced in three weeks, necessitating rotation with two other pesticides with a distinctly different biochemical action in the fly. This, however, was a tropical setting with a very high fly breeding rate and therefore high rate of gene exchange in the population, which would have been likely to produce widespread mutation and hence resistance at a far higher rate than might occur in Penrith.

The continuing effectiveness of dichlorvos use in open granaries or on refuse tips without the production of resistant strains of fly is deceptive in that new, susceptible genes are always being introduced into the mesoenvironmental pool from far flung areas (in the case of granaries, from distant fields from which the crop is harvested, and in the case of tips, from bins in distant suburbs).

To reduce widespread reliance on the product in Penrith with the accompanying risk of resistance, the following is recommended:

 Use of a multiple barrier approach to fly breeding, to include physical control strategies, to which flies cannot develop resistance (eg: removal of food from the green waste stream, health education regarding placement of food items immediately in the bin or to refrigerate unwanted food waste until disposal, improving the seal on bins, use of a plastic liner, more frequent garbage removal to the tip, etc.).

Such approaches naturally require effective health risk management, including further risk assessment relating specifically to this area, careful policy development and implementation and routine (say three monthly) intervention assessment, including laboratory checking of the fly population for resistance, or the more simple counting of adult flies through the placement of bait traps in a number of public places in Penrith.

 The rotation of pesticides where any suspected resistance is suspected. Continued rotation of the same two or three pesticides makes use of the knowledge that fly populations which develop resistance through rapid mutation just as readily lose the resistance when exposure to the environmental threat (ie: the pesticide) ceases.

If a dichlorvos resistant fly population therefore develops in two to three months, and the dichlorvos exposure is removed, the fly population is likely to return to a dichlorvos-sensitive one again in a slightly longer period.

In the tropical field situation involving open garbage pits as described by the author in an earlier paragraph, three pesticides were effectively rotated in this fashion for two years, until budgeting allowed for a better solution in terms of a garbage removal service with bins, removal vehicles and controlled tipping. It must be kept in mind, however, that in this example contact pesticides were being applied to the surface of the refuse in a spray or powder form and that this was a semi-rural area with easy access to the pits, and established field pest control team which had experience in using chemical agents. Rotating insecticides in the case of Penrith might not be practical given the need for the public to use a relatively safe and simple agent in a ready-made device, suggesting that over-use should be avoided. There a few safe fumigant alternatives to dichlorvos and other organophosphate pesticides would have to be directly applied to the garbage in the bin necessitating a spraying operation either by Council or the residents. This would be unlikely to meet safety requirements in a built-up urban area such as Penrith, would probably be unacceptable to residents, and would lack cost effectiveness.

Given these complications, it would seem that a multiple barrier approach is needed, possibly including the separation of green and food waste through the use of a physical barrier such as biodegradable plastic bags.In this regard, however, the term “biodegradable” as applied to plastic bags is misleading and their use is likely to introduce fine plastic components to the waste stream intended for composting.

HAZARD IDENTIFICATION RELATING TO BINKILL USE IN PENRITH

An initial step in the risk assessment was the identification of a comprehensive range of potential hazards and their contributory factors (figure 1). This was based on a knowledge of the substances contained in Binkill, as discussed in phase 1 of the report, and the intended procedure for use in Penrith. The identified hazards, the main reasons for their inclusion, and factors contributing to their identification are listed in Table 1:

Table 1: Identified potential hazards relating to Binkill use in Penrith, with reasons for their inclusion, and contributory factors

Potential Reason/s for inclusion Contributory factors hazardous event Indoor use of Binkill The product has been designed  The product packaging is not labelled to indicate that it is for outdoor by Penrith residents for outdoor use only and could use only present a hazard, as did PVC  The recent refusal by the Australian Pesticides and Veterinary resin strips, when used indoors Medicines Authority (APVMA) to re-register PVC resin strips (see part 1 of the report, page containing more than 20% dichlorvos for indoor use has resulted in 13) cessation of availability of a well-known indoor pest control product. Binkill might therefore be misused by the Penrith public for use in indoor cupboards to kill fishmoths, cockroaches, etc., with resultant undesirable exposure.

Residents keeping This represents a case of indoor  The product packaging is not labelled to indicate that it is for outdoor the wheelie bin use of a product designed only use only. fitted with Binkill for outdoor use.  There is a possibility that some residents might keep the greenwaste indoors wheelie bin indoors, as a ready receptacle for food scraps.  The bin might be kept in a confined space, such as a pantry or walk- in cupboard.

Potential Reason/s for inclusion Contributory factors hazardous event Storage of a number The current plastic inner  Polymerised plastic wrappings are typically non-polar and therefore of Binkill packages packaging around the device is pervious to vapour from both dichlorvos and naphthalene indoors by residents, thin and there is an odour of  It is possible that the distributor/seller of Binkill is using an with exposure to dichlorvos and naphthalene unsuitable type of packaging for the device, and that a different type vapour escaping associated with the unopened of packaging such as phenylethene (styrene) with an acrylonitrile from the apparently product. In the supermarket one copolymer, as used in the cosmetics industry to provide a barrier to inadequate can smell the naphthalene volatile solvents, should be in use. packaging through the packaging at a  Given the apparently inadequate packaging, storage of a number of distance of 300 cm. packages in a confined space indoors might release sufficient quantities of the vapour to be toxic to humans

Storage of a large Council might bulk-buy the  The concentration of dichlorvos and naphthalene fumigant gas number of Binkill product and keep this item in released into a space by the product is dependent on a number of packages in an stores for distribution to the factors, including the volume of the space, the number of units indoor store, with public present, the ambient temperature, and humidity, etc. The product has exposure of Council already been observed to emanate the odour of naphthalene and staff to vapour possibly dichlorvos during storage and in this regard its packaging escaping the needs re-examination. apparently  Where large numbers of units are stored in a relatively confined inadequate space a risk might exist to Council staff from both the dichlorvos packaging (report Part 1, pages 13 to 14), and from the naphthalene, particularly where staff have an existing G6PD deficiency (report Part 1, page 25)  Given these factors, the storage space, potential temperature and product units to be stored by Council needs examination with a view to adequate ventilation and precautionary signage. In this regard a multiple barrier approach could be adopted to take into account any changes in packaging which might be made by the distributor of Binkill. It is doubted if PPE would be required, or would be economically viable.

Potential Reason/s for inclusion Contributory factors hazardous event Child ingesting Chips and flakes of the active  Such flakes could fall on the floor when the product is opened and be flakes of ingredient were found in the picked up and ingested by a young child, as young children have a naphthalene protective plastic envelope tendency to exhibit pica (placing in the mouth and eating of small containing which contains the red objects found on the floor or ground). This is aggravated by the fact dichlorvos, which fumigation device prior to that children appear to be attracted by the smell, texture and taste of fall from the opening. naphthalene, as discussed in part 1 of the report, page 26. package on opening  Up to 3 grams of flaked material was found in some of the packages. This had presumably broken off from the main cake and exited the device via ventilation holes into the plastic packaging. Given the 80% naphthalene content of the product this would yield 2.4 grams of naphthalene which would be adequate to kill one small child in terms of the worst case scenario for naphthalene poisoning reported in the literature (part 1 of the report, page 26).  Dichlorvos is more toxic than naphthalene so one could assume that the dichlorvos dose from these chips might also be fatal to a small child.

Child gaining access Currently the packaging is  The protective packaging consists of a cardboard outer box to the dispenser relatively easy to open because containing a thin, transparent plastic internal envelope, with two V- through tampering of two V-cuts placed in the cut to facilitate easy opening. with packaging plastic envelope by the  Scissors are not required to open the present packaging, which could distributor easily be opened by a child over the age of two years who is skilled at opening lolly packaging which often has a similar opening arrangement

Potential Reason/s for inclusion Contributory factors hazardous event Access to, and It is possible that poisoning could  While the outer cardboard container contains a warning “POISON sucking of, the occur were a child to gain access to Keep out of reach of children” in red lettering on a white panel, it dispenser containing the device described as a “tamper would be relatively easy to open the cardboard box containing the the naphthalene/ proof container” by the Distributor plastic envelope which holds the dispensing device. dichlorvos cake by a of Binkill.  The relatively thin, plastic envelope allows the odour of naphthalene child to pass. This probably diffuses through the thin plastic which suggests that it is made of the incorrect material for effectively containing dichlorvos and naphthalene vapour. This odour is known to be attractive to small children (part 1, page 26 of the report) and might encourage tampering.  While the plastic packaging is relatively strong, it has a “V” indentation for ease of opening which a two year old child with skills for opening lolly packaging could easily negotiate (unfortunately the literature is devoid of information relating to the ability of children to negotiate packaging). The packaging is thin enough to be bitten through by a smaller child and in this way the child might gain access to flakes and other particles of naphthalene which have been observed to be broken free from the central block, exiting the dispenser through the fumigation holes to enter the plastic packet.  The fumigant dispensing device itself is very strong and the joints are sealed. It would therefore be very difficult for a young child to open the device to gain direct access to the naphthalene/dichlorvos block. It is also too large to be placed in its entirety in the mouth of a child but could be sucked resulting in ingestion of some of the contents of the block in the saliva. A worse scenario is that the chips and flakes of naphthalene/dichlorvos could be ingested, with a potentially fatal outcome.

Potential Reason/s for inclusion Contributory factors hazardous event Prolonged (greater With increasing levels of vagrancy Exposure would be aggravated by the following factors: than one day) in Sydney, potentially overspilling  Prolonging of exposure where the vagrant is under the influence of exposure to fumes into Penrith, it is possible that a alcohol or other narcotic substance, or is ill from Binkill by a vagrant might enter a dumpster  Genetic predisposition to G6PD deficiency, particularly in African, vagrant using a fitted with Binkill for shelter and Middle-Eastern and South Asian males, with the occurrence of slow dumpster for shelter be exposed to toxic fumes. haemolytic reaction producing anaemia, or a rapid haemolytic event resulting in haemoglobinuria and potentially death.  Fitting of the bin with multiple dispensers  High day temperature with low humidity  Elevated temperature in the bin subjected to direct sunshine, particularly where the bin is dark in colour

Prolonged (more It is possible that children might  Although this is a less likely scenario than a vagrant entering a than one day) enter a clean wheelie bin to play, dumpster, and exposure is likely to be much shorter term, thi type of exposure of a child or might mimic child behaviour exposure need to be considered. entering a dumpster exhibited on television and films or wheelie bin to where children have entered fumes from Binkill dumpsters to play or seek refuge

Potential Reason/s for inclusion Contributory factors hazardous event Entry of dichlorvos By entering the green/food waste  The product has a cable tie for securing the dispenser to the bin lid. into the green/food stream the unspent product might While the construction of a Sulo bin is not correctly shown in the waste stream with potentially impact on the Binkill instructions for installing the device, it should be possible for possible impact on environment where composted members of the public to secure it with little trouble. the environment green/food waste is used.  Some members of the public, however, might elect to throw the during the device into the bin or to hang it from a branch or other garden waste application of in the bin, where it could enter the waste stream. compost  Members of the public fitting a new product on a regular basis might manufactured from dispose of the old, partially spent product by cutting it free and the green/food waste allowing it to fall into the green/food waste bin, when it could enter stream. the green/food waste stream  While birds and many useful insects are particularly sensitive to dichlorvos as a toxin, it is likely that any unspent or partially spent device would be removed during the separation of larger items of plastic from the composting stream.

Entry into the The disposal advice given by the  Placement of partially spent dispensers into the garbage waste stream general waste stream distributor on the packaging is is unlikely to produce a problem in that the product is likely to by the unspent “Dispose of empty container by dissipate in the garbage in a controlled tip, exiting the tip as a volatile device being placed wrapping in paper, placing in a gas. directly onto the plastic bag and putting in the  Because the substances are non-polar, with a low solubility in polar garbage bin by garbage”. Members of the public water (the unwritten law of solvency is “like dissolves like”), the members of the are, however, likely to throw the dichlorvos and naphthalene are unlikely to dissolve or remain in public spent dispenser, and any packaging water for any length of time, and are therefore unlikely to influence which it came in (including chips the quality of tip laechate which has potential to enter the water table of the naphthalene/dichlorvos in tips without clay or plastic lining. block already observed to be free in the plastic packaging), directly into the garbage

Potential Reason/s for inclusion Contributory factors hazardous event The development of Most synthetic pesticides,  House flies in Penrith would represent a relatively limited genetic pesticide resistance including dichlorvos, produce pool with minimal introduction of new susceptible genes from an by flies to insect resistance after a few weeks external environment. Given that only one insecticide is intended for dichlorvos, as or months exposure use in the control of the specific fly problem, were the product to be contained in Binkill, used in all wheelie bins, then resistance would be almost inevitable. with possible fly  There are limited opportunities for rotating pesticides as other types infestation of which are not fumigants, do not present the same level of practical Penrith and safe use as dichlorvos.  A multiple barrier approach would need to introduce physical barriers to overcome the chemical resistance problem, and this will introduce new challenges.  Given these factors, it would seem that the distribution of Binkill should be limited to address complaints and observed cases of fly breeding, and that Binkill should therefore be used in conjunction with a multiple barrier approach to fly breeding.

RISK ESTIMATION THEORY APPLIED IN THIS ASSESSMENT

The following step was the quantitative estimation of risk associated with each hazard. In this process the following simple linear equation for risk was assumed:

r = p x c where: r = risk p = probability or likelihood that a specific hazardous event would occur in a certain period of time c = consequence or outcome should that hazardous event occur

In reality risk events usually follow more complex equations, based on exponential relationships. Without knowledge of these exponential relationships, however, an assumed linear relationship is a generally acceptable practice. A further assumption was that qualitative values on an ordinal scale could be used to generate numerical values on a nominal scale. While not strictly mathematically correct this process is widely accepted by statisticians when they manipulate ranked values in tests like Spearman’s Rank Correlation Coefficient, or develop a cutoff points in a χ2 -test.

Because such risk estimation is based on a series of assumptions, it is important to give an indication of confidence associated with the estimation of each assumption, and for this reason an uncertainty index (u) was given to each estimate. This approach has been used before in the estimate of risk and has been subjected to scrutiny in the peer reviewed literature (Derry, 2006).

The ordinal tables used in the estimation of p, c and u are set out in tables 2, 3 and 4 below:

Table 2: Table for the estimation of probability value (p) for each potential hazard

Median Descriptor Criteria Value of p 1 Rare This event is just possible but very unlikely to happen in the Penrith Council area. It would occur less than once a year.

3 Unlikely or This event is possible, but unlikely to happen often in the uncommon Penrith Council area. It might occur only once in every six months or so. 5 Likely or This event is probable in the Penrith Council area. It might quite occur a few times each month. common 7 Highly likely This event is highly probably in the Penrith Council area. It and frequent might occur a few times each week.

9 Inevitable This event is inevitable in the Penrith Council area. It occurs or might occur on a daily basis.

Table 3: Table for the estimation of consequence value (c) for each potential hazard

Median Descriptor Criteria Value of c 1 No health No health effect on individuals or on groups. effect or ecological No environmental impact. impact

3 Minor health Minor and short term health effect. effect or ecological Some death of insects other than target species at local site, impact in particular bees

5 Moderate Moderate health effect with some severe, short-term health effect symptoms (hours to days). or ecological impact Death of a considerable number of insects other than target species in surrounding area (20-30m), particularly bees

7 Major health Acute effects with possible long-term or permanent impact. effect or Possible environmental health or statutory notification ecological required. impact Widespread death of insects and possibly amphibians over a considerable area. Impact of concern on threatened species.

9 Extreme Serious and life threatening health effects, possibly death. health effect Possible impact on large groups of individuals with complex or ecological environmental clean-up, or long-term evacuation, required. impact Catastrophic loss of fauna across a considerable local area; irreversible loss of biodiversity; serious and permanent ecosystem impacts; or loss of threatened species.

Note: decisions made on the basis of this table need to be considered in terms of the health impacts of dichlorvos and naphthalene contained in Part 1 of this report.

Table 4: Table for the estimation of uncertainty (u) for each of the assigned values

Value (u) Descriptor Criteria 1 Extremely I am absolutely certain of this estimation. I have unchallengeable certain information to support my estimation. 3 Highly I am highly certain of this estimation. I have very good certain information to support my estimation. 5 Fairly I am fairly certain of my estimation. I have some information to certain support my estimation. 7 Fairly I am unsure of my estimation. I have little evidence to support my uncertain estimation. 9 Highly I am highly uncertain of this estimation. I have no supportive uncertain information to support my estimation.

For the preliminary estimation of risk required by Penrith Council, information at the disposal of the contracted Toxicologist and the Community Protection Manager, Penrith Council, was examined to provide an estimate of probability (p) of events occurring, and uncertainty (u) attached to each estimate. Each of these specialists had an interest in the assessment.

Consequence (c) was estimated from the literature on dichlorvos and naphthalene, from Part 1 of the report, and from site inspections carried out in Penrith, St Marys and Kemps Creek.

RAW DATA

The raw data used in risk estimation are shown in Appendix A. To keep this to a manageable format underpinning calculations and estimation criteria have not been shown but these could be supplied on request. Calculations were carried out using an Excel® spreadsheet, after which the spreadsheet was extracted in non-interative Word® form into the Report.

RANKED RISKS

The identified risk factors were ranked in terms of their estimated risk values (see table 5). Events which were not regarded to present a hazard for reasons already discussed have not been included in the table.

Hazards with risk values above the first quartile (25%) are considered to require priority attention (red zone in table 5), and have therefore been given priority in the section on Recommendations to Council.

Hazards in the first octile are suspect (orange zone in table 5), are suspect, and need to be kept under observation.

Other hazards probably represent a low risk and should only be kept on record by the Council, until circumstances relating to these hazards change.

ASSOCIATED UNCERTAINTIES

All hazards have a high level of associated uncertainty (above the first quartile) which is acceptable for a preliminary investigation. Further investigation is therefore indicated, although this should not stop Council from applying suitable early intervention for the higher risk hazards, in terms of the Precautionary Principle.

Table 5: Potentially hazardous events ranked in order of priority, with calculated risk values and estimated uncertainty indices

Risk rank Potentially Hazardous Event Risk value Uncertainty (priority) (r) index (u) 1 Child ingesting chips or flakes of naphthalene containing dichlorvos, which currently fall from 36 50 the Binkill package on opening 2 Child gaining access to the dispenser through tampering with the inadequate packaging 36 50

3 Indoor use of Binkill in cupboards (including bedroom cupboards) by residents in absence of 30 65 specific labelling restricting product to outdoor use 4 The development of pesticide resistance by flies to dichlorvos, as contained in Binkill, with 14 35 possible fly infestation of Penrith 5 Residents keeping the wheelie bin fitted with Binkill indoors 8 80

6 Storage of bulk Binkill packages in an indoor store, with exposure of residents to the vapour from 8 70 the present packaging 7 Prolonged (greater than one day) exposure of a vagrant using a dumpster for shelter to fumes 7 60 from Binkill 8 Prolonged (greater than one day) exposure of children entering a dumpster or wheelie bin to 7 75 fumes from Binkill 9 Access to, and sucking of, a correctly placed fumigant dispensing device by a child 7 70

10 Storage of a large number of Binkill packages in an indoor store, with exposure of Council staff 6 60 to vapour escaping the present packaging 11 Entry into the green/food waste stream by the unspent device becoming detached from the bin. 4 45

12 Entry into the green/food waste stream by the unspent device being placed directly onto the the 4 45 bin by members of the public

CONCLUSIONS

1. Suitability of dichlorvos

Dichlorvos is a good pesticide of choice for the intended application, in terms of its relatively low health risk, effectiveness in killing flies and their immature forms, ability to dissipate readily and low associated cost.

2. Suitability of Binkill

The product Binkill which contains dichlorvos dissolved in a naphthalene cake suffers from a number of inherent problems which should be addressed by Council before it is recommended or issued for general public use. These include:

2.1 Inadequate labelling

The product packaging does not contain a statement that it is only to be used for outdoor application (figure 2 below). Part 1 of the report draws attention to the fact that other products containing slow release dichlorvos are no longer registered by the APVMA for indoor use (Report part 1, page 13) and that the registration of Binkill is continuing because it is only for outdoor use (Report part 1, page 14). Given that indoor dichlorvos pest strips will cease to be available it is possible that misuse of the strips by the public will take place (table 5). In terms of responsible distributor policy, and in the liability interests of Council which will be distributing and recommending Binkill, there should be adequate labelling on the Binkill box to deter indoor use.

Figure2: Binkill box, plastic envelope and device containing dichlorvos/naphthalene block

2.1 Presence of chips of solid pesticide in the protective plastic envelope

After examination of a number of Binkill packages in a large supermarket it was found that in most cases, chips had broken off the dichlorvos/naphalene cake in the dispenser, exiting the dispenser from the ventilation holes and entering the plastic envelope (figure 3 below). These could fall to the floor when the packaging is opened and be ingested by an infant or toddler. The auditor has estimated that the quantity observed in some packaging could be fatal to a crawling infant in terms of a worst case scenario for naphthalene recorded in the literature (Report part 1, page 26). This is probably a conservative estimate given that in addition dichlorvos is dissolved in the naphthalene.

Figure 3: Binkill plastic envelope showing dichlorvos/naphthalene chips (black arrow) outside the dispenser in the envelope adjacent to the V-notch for opening (white arrow)

2.2 Inadequate child-proof nature of the packaging

The easy-open V-notch in the envelope is unsuitable for a product containing a pesticide. This is particularly hazardous given that:  there are chips of dichlorvos/naphthalene in many of the protective envelopes observed in a supermarket.  children are attracted to the odour of naphthalene and subsequently exhibit pica (placing the substance in the mouth, often with ingestion). In the case of naphthalene this is known to have severe or fatal consequences (Report part 1, page 26).  the V-notch is a common device in lolly-packaging to allow children access to the contents and as a result even small children are likely to be able to gain access to the chips or the dispenser.

 The outer cardboard packaging (figure 2, on the left), could easily be opened by a young child, affording no additional protection.

3. Items with an acceptably low risk

The following originally-identified hazards were investigated and found to be within an acceptable risk threshold:

3.1 the storage of a large number of Binkill packages indoors by a resident with subsequent exposure to fumigant passing through the apparently inadequate packaging was found to be within the selected risk threshold. Exposure from this source is considered to be an unlikely scenario in terms of Council’s Binkill issuing policy and is therefore unlikely to occur.

3.2 The storage of bulk stores of Binkill by Council in a poorly ventilated area with subsequent exposure of staff was found to be within the selected risk threshold. The intended bulk storage area was visited by the toxicologist on 16/04/2010 and found to be secure, well-ventilated and not generally occupied by staff for any length of time.

3.3 The exposure of a child for a prolonged period to Binkill fumigant through the entering of a dumpster to hide or play was found to be within the selected risk threshold. The risk assessment suggested it is an unlikely scenario, presenting minimal exposure risk.

3.4 Entry of dichlorvos into the green/food-waste composting stream in terms of an unspent Binkill dispenser becoming detached from the wheelie bin, or the cable tie being cut before the product was spent was found to be within the risk threshold. It is considered to represent an atypical event resulting in low residual pesticide levels in the composting stream, which would be unlikely to be retained in compost owing to volatility of dichlorvos. Reduction of plastic and other material in the stream to a low size should also ensure minimal concentration or retention of dichlorvos in any solid material. An environmental threat through the application of the resulting compost would therefore be minimal to non-existent.

3.5 Entry of dichlorvos into the garbage waste stream through disposal of an unspent dispenser was considered to represent a hazard within the accepted risk threshold. It would represent a relatively uncommon event and any dichlorvos entering the stream would be unlikely to remain in the garbage for a prolonged period, given dichlorvos’ fumigant nature and low retention characteristics in food and other substances.

3.6 Vagrancy exists at a low level and there is said to be no evidence of vagrants using dumpsters for sleeping purposes in the area. Hazards associated with this scenario are therefore minimal.

3.7 The development of fly resistance to dichlorvos was found to be within the accepted risk threshold. It is unlikely to occur rapidly given that general use of the pesticide in all wheelie bins is not the intended aim of Council and that it will only be issued or recommended in occasional cases where fly breeding is occurring. In

addition, Council intends to use a multiple barrier approach to the occurrence of fly breeding through education of the Penrith public on the correct storage and management of putrescible food scraps, the encouragement of use of biodegradable small plastic bags for food scraps before placement in the larger wheelie bin bag, the use of impervious bin liners, and increased frequency of removal in response to complaints or periods of exceptionally hot weather or humidity. Given that a low proportion (less than 10%) of the Muscid genetic pool is likely to be exposed to the pesticide, the conditions under which inheritable insect resistance to OP pesticides is usually established, are unlikely to occur, but this risk rating could change rapidly with any move toward widespread use.

RECOMMENDATIONS TO COUNCIL

The following recommendations are made to Penrith Council in the interests of risk management relating to the storage of Binkill on Council’s premises, and the use or issuing of Binkill to the residents of Penrith:

1. Improved labelling of Binkill

Council should advise the distributor of Binkill of the need for labelling on the box which states “FOR OUTDOOR USE ONLY”. This should have similar prominence and appearance to the labelling which currently reads “KEEP OUT OF REACH OF CHILDREN” and “READ SAFETY DIRECTIONS”.

If the distributor is unable to carry out this measure, then it is recommended that Council add a sticker to each box to include this statement to appear beneath the existing white panel bearing the above warnings, and with similar lettering and appearance.

2. Improved packaging of Binkill

Council should advise the distributor of the need for safer internal packaging which does not have the easy-open V-notch but which requires at least the cutting of the envelope to gain access to the dispenser. If Binkill are unable to comply it is suggested that Council places folded cellophane tape over this V-notch or seals the entire product (including the outer packaging) in a heat-sealed plastic envelope before issuing to the public. This might also help to reduce some of the vapour which apparently emanates from the existing product.

3. Return of defective Binkill to the distributor

Quality control with regard to the integrity of the product is apparently poor, with chips and flakes of the naphthalene dichlorvos cake finding their way into the surrounding plastic envelope. Council should check each product before issuing and return the product if it contains more than three to four grains or flakes greater than typical beach-sand size (1-2 mm) the product should be returned to the distributor or seller (the amount shown in figure 3.3 could be fatal to a child in terms of a worst-case scenario based on the literature relating to naphthalene alone) (Report part 1 page 26).

4. Cautionary handout with Binkill

Council should issue a cautionary handout with any Binkill given to the public to cover the following:

 The need to store the product out of the reach of children. A high, locked cupboard is recommended.  The need for parents to warn children not to touch or play with the product.  A warning about the need to remove and discard any chips or flakes of the product found in the plastic envelope outside the red device, in the garbage bin before use.  The need to attach the product to the wheelie bin using the cable tie as advised by Binkill.  The need to wash hands well after handling the product.

5. Issuing of individual boxes of Binkill to the public by Council staff

Because of the apparent inadequacy of the current packaging which consists of a plastic envelope through which vapour of naphthalene and probably dichlorvos emanates (it is possible to smell the product through this plastic), the following measures are recommended:

 The distributor could be approached regarding the inadequacy of the current plastic packaging with a view to placement of the product in packaging which does not allow vapour to escape to achieve little or no odour emanating from the packaging. If the distributor is non-compliant, Council could consider supplying each box of Binkill in an additional, heat-sealed plastic outer envelope (without easy-open V-notch) to prevent the current escape of vapour. In this regard the packaging industry could be consulted as there are plastic envelopes used for cosmetics which reduce or block the passage of non-polar vapour.

 If the product is supplied in the current packaging, then Binkill should not be kept at the work station but in a suitably secured, separate and ventilated storage area which is visited by the staff member each time a package is to be issued to a member of the public. Given this barrier precaution, and the intended rate of issuing the product, any risk presented to Most Sensitive Individuals (MSIs) (eg: pregnant or lactating women, or individuals with glucose-6-phosphate dehydrogenase deficiency), should be well within acceptable limits.

 If Council staff carry out the in-situ supply of Binkill, and the packaging and quality control of cake manufacture has not been improved as suggested above, then staff should be advised to transport the bulk product in a well-ventilated vehicle, and to ensure that chips of naphthalene/dichlorvos do not fall to the ground when opening the package. Placement of the chips in the wheelie bin should be an adequate disposal solution.

REFERENCES

(Please also consult the comprehensive reference list to Part 1 of the report as many of the references are also useful in the general argumentation to Part 2 of the report).

Acevedo GR, Zapater M, Toloza, AC, 2009. Insecticide resistance of house fly, Musca domestica from Argentina, Parasitology Research 105, 489-493.

Brodbeck HW, 1969. Herms’s medical entomology, Macmillan, London.

Cirillo VJ, 2006. Winged sponges": Houseflies as carriers of typhoid fever in 19th- and early 20th-century military camps, Perspectives in Biology and Medicine, 49, 52-63.

Crossley RW, Lane RP, 1995. House flies, blowflies and other allies. In: Medical Insects and Arachnids (Eds.: Lane RP, Crossley RW), Chapman and Hall, London.

Derry C, Attwater R, 2006. Risk perception and communication relating to effluent irrigation on a University campus, Water, 33, 57-62.

Derry C, Attwater R, Booth S, 2006. Rapid health-risk assessment of effluent irrigation on an Australian university campus. International Journal of Hygiene and Environmental Health, 209, 159-171.

Dogra SS, Mahajan VK, 2009. Oral myiasis caused by Musca domestica larvae in a child, International Journal of Pediatric Otorhinolaryngology, 25 June, online.

Eldridge BF, Edman JD (Eds.), 2000. Medical entomology: a textbook on public health and veterinary problems caused by arthropods, Kluwer, Boston, USA.

Fetene T, Worku N., 2009. Public health importance of non-biting cyclorrhaphan flies Transactions of the Royal Society of Tropical Medicine and Hygiene, 103, 187-191.

Getachew S, Gebre-Michael T, Erko B, Balkew M, Medhin G, 2007. Non-biting cyclorrhaphan flies (Diptera) as carriers of intestinal human parasites in slum areas of Addis Ababa, Ethiopia, Acta Tropica, 103, 186-194.

Graham JP, Price LB, Evans SL, Graczyk TK, Silbergeld EK, 2009. Antibiotic resistant enterococci and staphylococci isolated from flies collected near confined poultry feeding operations, Science of The Total Environment, 407, 2701-2710.

Hadlington PW, Johnston JA, 1982. An introduction to Australian Insects, Uni of NSW Press, NSW, Australia.

Künast C, 1980. Resistance of House Flies (Musca domestica) to organophosphorous insecticides in South Germany, Anzeiger für Schädlingskunde Pflanzenschutz Umweltschutz 53, 21-24.

Miller GT, 2004. Sustaining the Earth, Thompson Learning Inc, Pacific Grove, California, USA.

Omenn Commission (The Presidential/Congressional Commission on risk assessment and risk management), 1997. A framework for environmental health risk management. Government Printing Office, Washington, DC., USA.

Price, NR, 1988. Insecticide-insensitive acetylcholinesterase from a laboratory selected and a field strain of housefly (Musca domestica), Comparative Biochemistry and Physiology: Pharmacology Toxicology and Endocrinology 90, 221-224.

Srinivasan R, Jambulingam P, Gunasekaran K, Boopathidoss PS, 2008. Tolerance of house fly, Musca domestica (Diptera: Muscidae) to dichlorvos (76% EC) an insecticide used for fly control in the tsunami-hit coastal villages of southern India, Acta Tropica, 105, 187-190.

Standards Australia/Standards New Zealand (SA/SNZ), 2009. Risk management- principles and guidelines, SA/SNZ ISO 31 000: 2009, Sydney, Australia.

APPENDIX A

Table of potential hazardous events, with associated probabilities, consequences, risks and uncertainties

Potential Hazardous Event p u[p] c u[c] r u Comment

Indoor use of Binkill 5 8 6 5 30 65 See table 1 Keeping a wheelie bin fitted with Binkill indoors 4 8 2 8 8 80 See table 1 Storage of bulk Binkill packages in an indoor store, with exposure of residents to vapour 2 8 4 6 8 70 See table 1 Storage of bulk Binkill packages in an indoor store, with exposure of Council staff to vapour 2 6 3 6 6 60 See table 1 Child ingesting flakes of naphthalene containing dichlorvos, which fall from the package on opening 4 6 9 4 36 50 See table 1 Child gaining access to the dispenser through tampering with the inadequate packaging 4 6 9 4 36 50 See table 1 Access to, and sucking of, a correctly placed fumigant dispensing device by a child 1 8 7 6 7 70 See table 1 Prolonged (greater than one day) exposure of a vagrant using a dumpster for shelter to fumes 1 5 7 7 7 60 See table 1 Prolonged (greater than one day) exposure of children entering a dumpster or wheelie bin to fumes 1 8 7 7 7 75 See table 1 Entry into the green/food waste stream by the unspent device becoming detached from the bin. 4 6 1 3 4 45 See table 1 Entry into the green/food waste stream by the unspent device placed directly into the the bin 4 6 1 3 4 45 See table 1 The development of pesticide resistance to dichlorvos, as contained in Binkill 2 3 7 4 14 35 See table 1