Identification of cattle poisoning by Bifenthrin via earwax analysis by HS/GC-MS.

The use of pyrethroids has increased over recent years, and corresponds to a higher exposure of animals to pesticide residues in the environment and diet. Here, an outbreak of pyrethroid poisoning in beef cattle was reported occurring in Midwestern Brazil. After veterinary evaluation, it was observed that the bovines presented common pyrethroid intoxication symptoms. Aiming to identify the cattle poising by pyrethroid, earwax samples were collected from two groups: exposed and nonexposed animals from the same farm. Blind earwax analyses of the bovines were carried out using headspace/gas chromatography-mass spectrometry (HS/GC-MS). The HS/GC-MS analysis detected the presence of bifenthrin in the earwax analysis of the exposed animals, confirmed by the comparison of its MS fragments with a bifenthrin standard, and also by its retention time relative to the internal standard. In summary, HS/GC-MS analysis of earwax emerges as a tool that can be used in the detection and monitoring of bifenthrin poisoning in cattle, as a useful veterinary diagnosis that ensures animal health and the safety of their products.

Qualitative identification of imidacloprid in postmortem animal tissue by gas chromatography-tandem mass spectrometry.

During an avian mass mortality event investigation at the National Fish and Wildlife Forensic Laboratory in Ashland, OR, imidacloprid became an insecticide of concern. A qualitative analytical toxicology screen of seeds, plucks (tongue, esophagus, and trachea), and ventricular contents was requested. A method for the extraction and qualitative analysis of the insecticide in animal tissues was therefore developed. The procedure relies on a combined Food Emergency Response Network (FERN) and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) approach to sample extraction followed by qualitative analysis by gas chromatography-tandem mass spectrometry. Since imidacloprid is not amenable to the conditions of gas chromatography, a trimethylsilyl derivative was created and characterized. Proposed mechanisms for the creation of this derivative and its mass spectrum are described. The imidacloprid-trimethylsilyl (TMS) derivative was detected in all samples submitted.

Animal sentinels for environmental and public health.

Studies of the effects of environmental exposures on domestic and wild animals can corroborate or inform epidemiologic studies in humans. Animals may be sensitive indicators of environmental hazards and provide an early warning system for public health intervention, as exemplified by the iconic canary in the coal mine. This article illustrates the application of animal sentinel research to elucidate the effects of exposure to traditional and emerging contaminants on human health. Focusing on environmental issues at the forefront of current public health research, the article describes exposures to community air pollution, environmental tobacco smoke, and pesticides and associations with cancer, reproductive outcomes, and infectious diseases. Finally, it covers the role of marine mammals in monitoring the health of the oceans and humans.

Fonofos poisons raptors and waterfowl several months after granular application.

From 1994 to 1999 in the Lower Fraser Valley region of southwest Canada, fonofos (Dyfonate G) was recommended for control of introduced wireworm (Agriotes spp.) pests on potato and other root crops. As part of a wildlife-monitoring program, we collected 15 raptors, including 12 bald eagles (Haliaeetus leucocephalus), found dead or debilitated on or near agricultural lands with severely inhibited brain and/or plasma cholinesterase activity and fonofos residues in ingesta. Bird remains, in nine cases waterfowl, were identified in the ingesta samples. Another seven bald eagles had severe cholinesterase inhibition, but without evidence of fonofos residues. During two winters from 1996 to 1998, 420 ha of potato fields, half of which had been treated the previous spring with fonofos and the remainder untreated, were searched weekly for evidence of wildlife mortality. Search efficiency was assessed with placed duck carcasses. Waterfowl outnumbered other species in field-use counts and comprised the greatest proportion of birds found dead. We found 211 wildlife remains, most scavenged; 35 intact carcasses were suitable for postmortem examination and/or toxicology analyses. Cholinesterase activity was assayed in brains of 18 waterfowl, five of which had severely depressed activity (average inhibition 74%; range, 69-78%). The gastrointestinal tract of a mallard found in a field treated with granular product contained 49 microg/g fonofos residues, linking waterfowl mortality with labelled use of the product. These findings demonstrate the risk of both primary and secondary poisoning by anticholinesterase insecticides where wildlife make intensive use of farmed fields.

Dichlorodiphenyltrichloroethane (DDT) for indoor residual spraying in Africa: how can it be used for malaria control?

In 2006, the World Health Organization issued a position statement promoting the use of indoor residual spraying (IRS) with dichlorodiphenyltrichloroethane (DDT) for malaria vector control in epidemic and endemic areas. Other international organizations concurred because of the great burden of malaria and the relative ineffectiveness of current treatment and control strategies. Although the Stockholm Convention of 2001 targeted DDT as 1 of 12 persistent organic pollutants for phase-out and eventual elimination, it allowed a provision for its continued indoor use for disease vector control. Although DDT is a low-cost antimalarial tool, the possible adverse human health and environmental effects of exposure through IRS must be carefully weighed against the benefits to malaria control. This article discusses the controversy surrounding the use of DDT for IRS; its effective implementation in Africa; recommendations for deployment today, and training, monitoring, and research needs for effective and sustainable implementation. We consider the costs and cost effectiveness of IRS with DDT, alternative insecticides to DDT, and the importance of integrated vector control if toxicity, resistance, and other issues restrict its use.

Acute intoxication due to ingestion of vegetables contaminated with aldicarb.

Three members of the same family ingested vegetables treated with aldicarb. All three developed signs and symptoms of acetylcholinesterase inhibition and all recovered a few hours after the ingestion. Reports of toxicity from the ingestion of aldicarb-contaminated food are uncommon. Aldicarb is a potent pesticide which can only be used safely if governmental and industry regulations are followed carefully.

Analytical methods used in the United Kingdom Wildlife Incident Investigation Scheme for the detection of animal poisoning by pesticides.

The United Kingdom Wildlife Incident Investigation Scheme (WIIS) investigates cases of suspected poisoning of wildlife, honey bees, and companion animals by pesticides. Together with field inquiries and veterinary post-mortem examinations, the analytical procedures presented here provide a comprehensive approach to the investigation of these cases. The paper covers selection of animal tissues for analysis and methods suitable for the analysis of honey bees and for various types of bait. Seven multiresidue methods cover around 130 pesticides, and methods are also described for a further 8 compounds. These methods are currently used on samples submitted to the Scheme in England and Wales.

Field populations of native Indian honey bees from pesticide intensive agricultural landscape show signs of impaired olfaction.

Little information is available regarding the adverse effects of pesticides on natural honey bee populations. This study highlights the detrimental effects of pesticides on honey bee olfaction through behavioural studies, scanning electron microscopic imaging of antennal sensillae and confocal microscopic studies of honey bee brains for calcium ions on Apis cerana, a native Indian honey bee species. There was a significant decrease in proboscis extension response and biologically active free calcium ions and adverse changes in antennal sensillae in pesticide exposed field honey bee populations compared to morphometrically similar honey bees sampled from low/no pesticide sites. Controlled laboratory experiments corroborated these findings. This study reports for the first time the changes in antennal sensillae, expression of Calpain 1(an important calcium binding protein) and resting state free calcium in brains of honey bees exposed to pesticide stress.

Overview of potential mutagenic problems posed by some pesticides and their trace impurities.

This review principally addresses a number of aspects of usage of pesticides as well as populations at potential risk and attempts to highlight categories of pesticides whose structures or those of their metabolites and/or trace impurities, degradation and transformation products suggest an a priori mutagenic and/or carcinogenic risk. The pesticides considered include: DDT, hexachlorobenzene (HCB), 2,4,5-T, pentachlorophenol, and various herbicidal precursors (e.g., carbamates, triazines) of nitrosamines and nitroso derivatives. Structural features of a number of halo-unsaturated pesticides (e.g., dichloropropenes) were also reviewed from a viewpoint of contrasting their potential mutagenicity with that of vinyl chloride and vinylidene chloride. Additionally the mutagenicity of the organophosphorus pesticide Trichlorophon is contrasted with that of its degradation products.

Identification of pesticide poisoning in wildlife.

The Wildlife Incident Investigation Scheme investigates incidents of suspected poisoning of wildlife (also honey bees and companion animals) by pesticides in the United Kingdom. The approach to these investigations has evolved over the past 30 years. Field investigations, post-mortem examinations, toxicological data and experience of previous poisoning incidents assist in the selection and interpretation of appropriate chemical analyses. Several 'multi-residue' and several 'individual compound' analytical methods for pesticides in wildlife are currently in use; these are described.

Swedish pesticide risk reduction 1981-1995: food residues, health hazard, and reported poisonings.

The Swedish Government has initiated three pesticide risk-reduction programs since the mid-1980s. Risk-reduction achievements have been measured mainly in terms of reduction in quantities sold. In this review, risk-reduction achievements have been described also in terms of pesticide residues in foods, both imported and grown domestically, acute health hazard to the users, and reported poisonings. The time periods selected for comparisons are 1981-1985 (which is the Government's baseline period), 1990-1994 for food residues and poisonings, and 1991-1995 for acute health hazard and quantities sold. The quantity of pesticides as active ingredient (ai) sold for use in agriculture, horticulture, and forestry decreased from a total of 22,800 tons during 1981-1985 to 8450 tons in 1991-1995, a 63% reduction. Published data on pesticide residues in domestically grown fruits and vegetables show that the proportion of cases of reported residues higher than 20% of the maximum residue limit has decreased only slightly, from 6.9% to 6.2%. Residues in imported food crops of the same type increased from 31% to 37%. Overall, the achieved 63% reduction of quantities used may have resulted in only a 10% reduction in number of cases of reported residues. A forthcoming report on pesticide intake via food from the National Food Administration may shed light on any trends in actual residue levels. The degree of goal fulfillment for the pesticide residue monitoring program and for pesticide residue levels in food is difficult to judge because of imprecise goal formulations. An estimate of the potential acute health hazard to the pesticide users, based on quantities and acute toxicity of individual pesticides, indicates that the acute health hazard in terms of "acute toxicity equivalents" decreased by 71%. The number of poisonings caused by acute exposure at the workplace has decreased between 1984 and 1994, whereas the number of mostly harmless incidents at home has increased. The decline in workplace-related accidents and the favorable pattern and low frequency of pesticide poisonings in Sweden compared to many other countries, especially developing countries, is the result of several factors, such as the mandatory training of workers using pesticides professionally, severe restrictions in availability of pesticides for use in households, and withdrawal from the market of the most toxic pesticides. To improve the worrisome global situation, it would seem appropriate that the United Nations Food and Agriculture Organization pay greater attention to the need for promotion of restrictions on availability of highly toxic and other pesticides, as recommended by FAO and WHO in 1975 (WHO/FAO 1975).

Toxaphene residues from cotton fields in soils and in the coastal environment of Nicaragua.

Toxaphene (camphechlor) was intensively used in the cotton growing fields of Nicaragua for decades with application rates as high as 31 kg ha(-1) in 1985. Although the use of this compound has recently been discontinued in the country, its intensive use in the past and its long persistence in soil allowed for the build up of large reservoirs of toxaphene in agriculture soils and a wide dispersal of residues in the environment. Measurements of toxaphene in coastal areas on the coast of the Pacific Ocean show that environmental concentrations are particularly high in the district of Chinandega, the traditional cotton growing region. Toxaphene residues measured in soils attained 44 microg g(-1) (dry weight) while concentrations in lagoon sediments attained 6.9 microg g(-1) (dry weight) near the mouth of the rivers flowing across the agricultural region. Measurements in aquatic biota showed concentrations as high as 1.6 microg g(-1) (dry weight) in the soft tissues of clams. The toxaphene reservoir in soils combined with the obvious persistence of this compound in soils and lagoon sediments allows predicting that toxaphene will remain in the coastal ecosystem at relatively high concentrations for many years. Toxic effects in lagoon fauna are likely to be observed especially in benthic species that may recycle this compound from sediments. Consumption of seafood, in particular of clams (Anadara spp.) from the more contaminated areas, may expose the population to unacceptably high intake of toxaphene, 30 microg d(-1) per person, with the diet.

Persistence of sodium monofluoroacetate in livestock animals and risk to humans.

1. Sodium monofluoroacetate (1080), a vertebrate pesticide widely used in New Zealand, was administered orally to sheep and goats at a dose level of 0.1 mg kg-1 body weight to assess risk to humans of secondary poisoning from meat. Blood, muscle, liver, and kidney were analysed for 1080 residues. 2. The plasma elimination half-life was 10.8 h in sheep and 5.4 h in goats. Concentrations of 1080 in muscle (0.042 microgram g-1), kidney (0.057 microgram g-1), and liver (0.021 microgram g-1) were substantially lower than those in plasma (0.098 microgram ml-1) at 2.5 h after dosing. 3. Only traces of 1080 (< 0.002 to 0.008 microgram g-1) were found in sheep tissues after 96 hours. 4. Livestock are normally excluded from areas where 1080 is being used for pest control, reducing the risk of secondary poisoning. Even with accidental exposure to a sublethal dose 1080 would not persist in tissues for more than a few days because it is cleared rapidly from the body. Therefore the occurrence of 1080 in meat intended for human consumption is highly unlikely.

Evidence of secondary poisoning of free-ranging riparian mustelids by anticoagulant rodenticides in France: implications for conservation of European mink (Mustela lutreola).

Because of the rapid decline of the endangered European mink (Mustela lutreola) populations in France, a national conservation program has been put into action, including research to understand the causes of decline. As part of this research, concentrations of eight anticoagulant rodenticides were examined in livers from 122 carcasses of four species of free-ranging mustelids collected between 1990 and 2002 in southwestern France. Bromadiolone residue was found in all species and 9% of the sample (one of 31 European mink, three of 47 American mink [Mustela vison], five of 33 polecats [Mustela putorius], and two of 11 European otters [Lutra lutra]). Liver concentrations ranged from 0.6 mug/g to 9.0 mug/g. Chlorophacinone residue was found in two species and 4% of the sample (in four of the American mink and in one of the otters), with liver concentrations ranging from 3.4 mug/g to 8.5 mug/g. Two polecats and one American mink had lesions and liver residues indicating bromadiolone was directly responsible for their death. However, most of our study animals survived secondary poisoning until they were caught; this study certainly underestimates the extent of fatal exposure of mustelids to rodenticides. Moreover, anticoagulant poisoning could increase their vulnerability to other causes of death. The current status of the endangered European mink population is such that any additional risk factor for mortality is important, and it is thus urgent to monitor and reduce the extensive use of bromadiolone and chlorophacinone against field rodents in France.

Lack of relay toxicity in ferret hybrids fed carbaryl-treated prairie dogs.

Carbaryl (1-napthol methylcarbamate) is being considered for control of fleas on prairie dogs (Cynomys spp.) used in black-footed ferret (Mustela nigripes) recovery in the western United States. The potential for relay toxicity in ferrets was determined by feeding carbaryl treated prairie dogs to black-footed ferret x Siberian polecat (M. eversmanni) hybrids. Adult prairie dogs were treated topically with 2.5 g of commercial 5% carbaryl dust sold as flea powder. After 14 days prairie dogs were killed and fed to ferrets. Potential for relay toxicity was evaluated by analyzing ferret blood cholinesterase (CHe), prairie dog brain Che, and hepatic carbamate concentration. There was no difference between pre- and post-exposure blood CHe activity, nor did treated prairie dog brain CHe differ significantly from controls. Post-exposure blood CHe did not exhibit reactivation after dilution in aqueous buffer. Hepatic carbaryl concentrations were less than detection limits (50 ppb). Based on these results, we conclude that short-term use of carbaryl for flea control on prairie dogs does not pose a hazard of relay toxicity in black-footed ferrets.

Effects of agricultural pesticides on humans, animals, and higher plants in developing countries.

Undesirable side effects that result from the indiscriminate use of agricultural pesticides in developing countries are widespread. This has captured the attention of health workers, governments, and environmental protection agencies. In fact, the potential health effects of long-term exposure to humans, animals, and higher plants are of great concern. This study examines the effects of agricultural pesticides on such living forms and explores modes of action, and presents strategies to minimize the deleterious effects of pesticides to living forms in developing countries.

Veterinary public health activities aimed at prevention of intoxications by chemical residues in foods of animal origin. Suggestions for inspection programmes.

Practically all today's raw agricultural products have been treated or exposed to one or more agricultural chemicals or veterinary products, in order to increase food production. A tremendous amount of work has been done by veterinarians in coping with diseases and health risks due to microorganisms, parasites and other agents of biological origin. There is no doubt that veterinary services, research and educational institutions have a long and successful tradition also in dealing with problems of chemicals associated with animal and food production, processing, transportation, storage and distribution. Due to the increasing quantity and large numbers of chemicals now used in animal production and related fields, it has however become indispensable to broaden and intensify the education and training of veterinarians, as well as to ensure their participation in all sectors of this field. Veterinarians should be fully involved in the surveillance, prevention and control of intoxications by chemical residues. They are well qualified to do this. They are working continuously in the areas where exposure to animals and food may occur, possess adequate knowledge of the routes of entry of such chemicals into food chains, the fate of their residues, the health hazards involved, as well as of the toxicology, pathology, pathophysiology, and food hygiene and technology. Residues present an enormous challenge for surveillance, prevention and control in agriculture, food processing and related activities.

The occurrence and importance of residues in meat and their evaluation within official meat inspection.

Food of animal origin is an important factor in protecting the consumer from health risks emanating from the environment. This is why chemical and drug residues in food animals have been included in the Meat Inspection Act in the Federal Republic of Germany. The following substances are subject to regulation: Drugs; Feed additives; Pesticides; Toxic substances from the environment. While drugs may give rise to resistance of infective agents to them, feed additives may accumulate in the organism and have a toxic effect. Pesticides themselves may not be harmful in the amounts, which accumulate in meat, however, their metabolic products in the human body may be toxic. Radioactive substances and radioactive fall-out as well as cadmium and mercury are dangerous when accumulating in meat. Therefor, fixation of tolerance levels for defined residues has been started to be set according to the new Foods Act, including their toxicological evaluation. Condemnation of organs of slaughter animals in which these chemicals accumulate is obligatory.

[Assessment of the chronic risk for ingestion of pesticide residues in the Brazilian diet]. / Avaliação de risco crônico da ingestão de resíduos de pesticidas na dieta brasileira.

OBJECTIVE: To conduct a chronic dietary risk assessment of the pesticides registered in Brazil up until 1999. METHODS: The Theoretical Maximum Daily Intake (TMDI) for each pesticide was calculated using the Brazilian maximum residue limits and food consumption data from IBGE, the Brazilian Statistical Institute. The risk characterization was done comparing the TMDI with the acceptable daily intakes (ADI) from other countries and from the Codex Alimentarius. RESULTS: The TMDI was higher than the ADI (%ADI>100) at least in one Brazilian metropolitan region for 23 pesticides. Sixteen compounds are organophosphate insecticides, with methyl parathion having the TMDI exceeding the most toxicological parameter (%ADI N=9,300). Rice, beans, citrus and tomato were the commodities which most contributed to the ingestion. From the compounds under higher risk, only 6 were registered according to the Law 98.816/90, which concerns the use of pesticides in the country. CONCLUSIONS: The compounds identified in the study as presenting a potential health concern to the Brazilian consumers, and the commodities which most contributed to the ingestion, should be prioritized by the government in pesticide residue monitoring programs and in the re-registration process. In addition, residue data in food as consumed, processing factors and appropriate consumption data should be generated to allow further studies.