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Pesticide personal protective clothing.

A fairly large established data base provides information on clothing worn by U.S. and Canadian farmers to work with pesticides, their attitudes and beliefs about pesticide risk, and clothing as a dermal barrier. Very limited similar data are available for farmers in less developed countries. Clearly, farmers perceive the benefits of pesticides to far exceed any risks. While few report poisoning symptoms, most believe that their usual work clothing offers a sufficient pesticide barrier, and few wear special-purpose protective clothing. Gloves of various materials, including cotton and leather, appear to be the major protective clothing item. Although farmers feel that their usual work clothing provides excellent protection, fabric penetration research does not support this. Shirting-weight fabrics offer some limited protection against light spray of field-strenght pesticides. Heavier-weight fabrics, such as denim and twill, are better barriers. With a heavier spray or a spill, usual work clothing does not give sufficient protection. Greater protection can usually be achieved with the use of a fluorocarbon finished fabric, such as Scotchgard or Zepel. Scotchgard can readily be applied at home. A durable-press finish does not appear to improve fabric's pesticide-barrier resistance and some data suggest that it may decrease barrier properties. A second alternative for increased protection is the use of a special-purpose fabric, such as a coated nonwoven or possibly Gore-Tex. Numerous other new "waterproof breathable" fabrics have recently come to the market. Many of these are finished or coated fabrics and one would expect them to be at least somewhat resistant to pesticides. However, they have not been tested. Wearing an additional layer also appears to be another clothing strategy to minimize exposure. Fabric penetration research also shows that pesticide formulation, volume or spray regime, concentration, and active ingredients influence the barrier properties of fabrics. Clothing evaluation studies have shown that protective clothing and coveralls of various materials and designs were effective in reducing exposure. Results of some of these studies suggested that the farmer's typical work clothing was more effective than fabric penetration results suggested. This apparent conflict is not surprising, given the methods used in both types of research. The field studies use pads placed in various areas under the clothing. This method assumes that exposure is uniform over entire body regions. But fluorescent tracer research has shown that this is not a valid assumption (DeJonge et al. 1985; Fenske 1988). Also, the way in which the pads are attached may make a difference, although no research has examined this issue.(ABSTRACT TRUNCATED AT 400 WORDS)

Agricultural Workers' Diseases↗

Dietary pesticide risk assessment.

In this review, the process of dietary pesticide risk assessment has been presented and three major components of the process--estimation of pesticide residue levels, estimation of food consumption patterns, and characterization of risk based on a comparison of exposure estimates with toxicological criteria--have been identified. Each component of the process is subject to considerable uncertainty that may compromise the accuracy of the final risk assessment. In estimating pesticide residue levels, common practices range from highly theoretical models assuming that all residues are present at a predetermined level (typically at the tolerance level) to the use of market basket survey data obtained at the time the food is ready for consumption. Intermediate techniques include using actual monitoring data (usually obtained from government residue enforcement programs) and/or making corrections to estimates on the basis of actual pesticide use. Additional corrections may be used to incorporate data on the effects of post-harvest practices such as processing, washing, cooking, peeling, and transportation that have often been shown to dramatically reduce residue levels, although occasional increases in residue levels and/or formation of toxicologically significant breakdown products may also result from post-harvest practices. Food consumption estimates are typically derived from national surveys of consumer food consumption behavior and are also subject to considerable uncertainty. Food consumption estimates are often disaggregated into distinct population subgroups based on age, gender, geographic region, and ethnicity, although the accuracy of estimates for particular subgroups is commonly questioned on the basis of the adequacy of sample size. At the present time, data from the 1977-78 Nationwide Food Consumption Survey are still being used, and the incorporation of more recent data from the 1987-88 Nationwide Food Consumption Survey is being delayed due to major flaws in the study. On occasion, other food consumption surveys may be used, although they are typically much smaller in scope than the 1977-78 and 1987-88 studies and are considered less reliable. The multiplication of residue level estimates by food consumption estimates yields an estimate of human pesticide exposure. Commonly, the theoretical maximum residue contribution (TMRC) is calculated that represents the maximum "legal" exposure to pesticides. Calculation of the TMRC involves the assumptions that all pesticides legally allowed on a particular commodity will always be applied, that all residues are present at the tolerance levels, and that there are no post-harvest effects on residue levels. Often the TMRC is used as a sorting tool by the EPA in its preliminary assessment of dietary risks to pesticides.(ABSTRACT TRUNCATED AT 400 WORDS)

Diet↗

Sublethal effects of three pesticides on Japanese medaka.

One- to 2-day-old medaka (Oryzias latipes) larvae were exposed for 4 days to the rice field pesticides methyl parathion, molinate, carbofuran and a mixture of all three. Pesticide concentrations were one-half the 96 h LC50 ("high concentration") and levels approximating those measured in receiving waters from rice field runoff ("low concentration"). Maximum swimming speed, spontaneous muscular activity, acetylcholinesterase activity, dry weight, RNA:DNA ratio, and five morphometric variables were determined at the end of the exposures. Larvae were retained for an additional 10 days in non-contaminated water, and the same measurements taken to investigate residual effects. Results are compared to a parallel study on striped bass larvae to evaluate the suitability of this species as a surrogate for the bass in toxicological studies involving sublethal exposures. There was no relationship between mortality rate and pesticide exposure either during the exposures or during the ten day subsequent period. Only the high concentration of carbofuran caused an impairment of swimming performance. Spontaneous activity was stimulated in the high concentration of molinate and the combined pesticides groups. Acetylcholinesterase was severely inhibited in parathion and molinate, and this persisted in some cases after 10 days in non-contaminated water. The pesticides had little effect on growth rate except for molinate which acted as a stimulant. Combining the three pesticides caused a less than additive effect. Except for decreases in acetylcholinesterase, the sublethal effects of the pesticides tested at the very low concentrations used were subtle. Apparently, larvae of this species are less sensitive to these pesticides than are striped bass larvae.

Animals↗

Comparison of the efficiencies of different types of adsorbents at trapping currently used pesticides in the gaseous phase using the technique of high-volume sampling.

Atmospheric samples were collected in an urban area (Strasbourg centre) in spring/summer 2004, in order to determine the concentrations of different pesticides in the gaseous and particulate phases and to compare the efficiencies of different adsorbents at trapping the gaseous phase. Two high-volume samplers were placed next to each other in the botanical garden in the centre of Strasbourg. Air sampling was carried out using a glass fibre filter and different adsorbents for 48 hrs. The following adsorbents and combinations of adsorbents were compared: XAD-2 with PUF, XAD4 with PUF, XAD-2 with a PUF-XAD2-PUF sandwich, PUF with a PUF-XAD4-PUF sandwich. In order of efficiency at trapping pesticides, the "sandwiches" are the most efficient, followed by XAD-2 and XAD-4 resins. However, although the "sandwiches" are slightly better at trapping than XAD-2, the use of XAD-2 is recommended for technical reasons. The PUFs are the least efficient at trapping. Among the 27 pesticides analysed, trifluralin, alachlor, metolachlor and captan were the most concentrated pesticides, followed by lindane, alpha-endosulfan and diflufenican. This result is in accordance with farming activity in the Alsace region, where the pesticides that are used on large crops (maize, cereals) are applied in the greatest quantities. Vineyards are another important form of agriculture in Alsace, but the quantities of pesticides applied in comparison to those used on large crops is very low, which explains the low detection of vineyard pesticides in air samples observed here. The concentrations are depend on the identities and properties of the pesticides analysed, but on the whole they remain rather low. It is important to perform measurements like these in the urban environment, as these compounds can be harmful to human health and the environment and so their concentrations need to be monitored.

Absorption↗

Kinetic transport of pesticide from contaminated fabric through a model skin.

Most protective clothing research for workers exposed to pesticides has focused on the primary dermal exposure that results from direct contact with the pesticide and on the penetration, versus repellency, of protective materials. The role of absorption and retention in the function of traditional clothing materials to limit pesticide exposure has received less attention. This project investigates the transfer of pesticides from contaminated work clothing in the dry state to human skin with the goal of furthering our understanding of the role of absorption and retention in the function of traditional clothing materials. Our objective was to study the use of synthetic membrane to evaluate the kinetic transport of pesticide from contaminated clothing through human skin. Transport of pesticide through the test system with and without the presence of fabric was characterized by a three-parameter single exponential rise to maximum equation. The synthetic membrane system was an appropriate model for human skin in this situation. Starching applied to the fabric gave additional absorption and retention, reducing pesticide transport from the fabric to the skin, and heavier weight fabric, such as denim, provided protection through absorption and retention of the pesticide.

Absorption↗

Laboratory investigation of the toxicity and interaction of pesticide mixtures in Daphnia magna.

The probabilistic ecological risk assessment-toxic equivalent (PERA-TE) combination approach is a relatively new risk assessment approach used to assess the toxicity and interaction of chemical mixtures. The validity and effectiveness of the PERA-TE combination approach has been tested previously in field microcosm studies using pesticide mixtures. The related laboratory studies described here, using Daphnia magna, were conducted to verify the conclusions made regarding the toxicity and interaction of the mixtures tested in the microcosms. Two types of pesticide mixture were assessed: the first consisted of pesticides with similar modes of action (chlorpyrifos, diazinon, and azinphos-methyl; OP mixture), and the second consisted of pesticides with different modes of action (chlorpyrifos, endosulfan, and trifluralin; CET mixture). Similar to the field studies, PERA-TE mixtures with a predetermined effect assessment criterion (10th centile of acute toxicity effects distributions) and proportional ratio (89:11 for binary mixture and 80:10:10 for ternary mixtures) were tested. Further assessment of the (PERA-) TE approach was achieved by altering the effect assessment criterion (to EC/LC(50) point estimates) and the proportional ratio of the pesticides in the mixture (to 50:25:25). Generally, but with some exceptions, basing mixtures on species-specific effect criteria and/or changing the proportional ratio of pesticides in the mixture redistributed the concentration of pesticides in the mixture to produce an equitoxic response. The ability to produce these equitoxic responses supported the conclusions drawn from the field studies: The pesticide toxicity in the OP and CET PERA-TE mixtures were effectively additive. Furthermore, it is shown that these alternative (PERA-) TE mixtures would be suitable to confirm or reject the interaction of chemicals in a PERA-TE mixture.

Animals↗

Development, registration and commercialization of microbial pesticides for plant protection.

Plant protection against pathogens, pests and weeds has been progressively reoriented from a therapeutic approach to a rational use of pesticide chemicals in which consumer health and environmental preservation prevail over any other productive or economic considerations. Microbial pesticides are being introduced in this new scenario of crop protection and currently several beneficial microorganisms are the active ingredients of a new generation of microbial pesticides or the basis for many natural products of microbial origin. The development of a microbial pesticide requires several steps addressed to its isolation in pure culture and screening by means of efficacy bioassays performed in vitro, ex vivo, in vivo, or in pilot trials under real conditions of application (field, greenhouse, post-harvest). For the commercial delivery of a microbial pesticide, the biocontrol agent must be produced at an industrial scale (fermentation), preserved for storage and formulated by means of biocompatible additives to increase survival and to improve the application and stability of the final product. Despite the relative high number of patents for biopesticides, only a few of them have materialized in a register for agricultural use. The excessive specificity in most cases and biosafety or environmental concerns in others are major limiting factors. Non-target effects may be possible in particular cases, such as displacement of beneficial microorganisms, allergenicity, toxinogencity (production of secondary metabolites toxic to plants, animals, or humans), pathogenicity (to plants or animals) by the agent itself or due to contaminants, or horizontal gene transfer of these characteristics to non-target microorganisms. However, these non-target effects should not be evaluated in an absolute manner, but relative to chemical control or the absence of any control of the target disease (for example, toxins derived from the pathogen). Consumer concerns about live microbes due to emerging food-borne diseases and bioterrorism do not help to create a socially receptive environment to microbial pesticides. The future of microbial pesticides is not only in developing new active ingredients based on microorganisms beneficial to plants, but in producing self-protected plants (so-called plant-incorporated pesticides) by transforming agronomically high-value crop plants with genes from biological control agents.

Animals↗

Brain tumor and exposure to pesticides in humans: a review of the epidemiologic data.

We examined the relationship between exposure to pesticides and the subsequent development of brain tumors in adults through a critical review of the literature. The results of retrospective case-control studies are conflicting, in part because of biases in the selection of patients and controls, poor definition and ascertainment of the nature and extent of the exposure to pesticides, and a non-uniform approach to the collection of antecedent information. A number of the studies evaluated farmers as a group exposed to pesticides; however, inference about cancer incidence in farmers may reflect not only their possible exposure to pesticides, but also exposure to petrochemical products, exhaust fumes, mineral and organic dusts, and biological exposure to animals and microbes. The great majority of the cohort studies of chemical workers employed in the manufacture of pesticides did not indicate an excess of brain cancer mortality. There have been few cohort studies of pesticide applicators and these revealed elevated but non-significant relative risks for excess mortality due to brain cancer. Existing data are insufficient to conclude that exposure to pesticides is a clear risk factor for brain tumors. Given the conflicting results reported for farmers and pesticide applicators and their contrast to chemical workers, it seems more plausible that exposure to multiple agents and/or other factors, such as genetic predisposition, are most relevant with respect to brain tumor pathogenesis.

Adult↗

In vitro and in vivo induction of heat shock (stress) protein (Hsp) gene expression by selected pesticides.

The chloroacetamide insecticide alachlor, polyhalogenated cyclic hydrocarbons endrin and chlordane and the organophosphate pesticides chlorpyrifos and fenthion induce oxidative tissue damaging effects including lipid peroxidation and nuclear DNA-single strand breaks. The mechanism involved in the induction of oxidative stress by these xenobiotics is unknown. No information is available regarding whether these pesticides can induce the expression of heat shock (stress) protein (Hsp) genes as a common protective mechanism against tissue damage. The pesticides were administered p.o. individually to female Sprague-Dawley rats in two 0.25 LD50 doses at 0 h and 21 h. The animals were killed at 24 h, and liver, brain, heart and lung tissues were removed to examine the induction of Hsps by Western and Northern blot analysis. In a separate series of experiments, cultured neuroactive PC-12 cells were treated 24 h with 50, 100 or 200 nM concentrations of these pesticides. Alachlor, endrin, chlorpyrifos and fenthion induced Hsp89 alpha and Hsp89 beta in hepatic and brain tissues, as well as in cultured PC-12 cells. Chlordane induced some expression of Hsp89 alpha but not Hsp89 beta in the hepatic and brain tissues of treated rats. Some expression of Hsp89 beta was observed in lung tissues of endrin and alachlor treated animals. These findings were substantiated by Western blot analysis using Hsp90 antibody. Except chlordane all these pesticides induced enhanced synthesis of Hsp90 in cultured PC-12 cells. The results indicate striking tissue differences in the patterns of the Hsps induced by the pesticides which were used, and demonstrate that these pesticides can induce the expression of Hsp89 alpha and Hsp89 beta genes in various target organs of rats. The results support the hypothesis that these genes may be mechanistically involved in protecting tissues against oxidative stress induced by structurally diverse pesticides.

Acetamides↗

Calculating pesticide sorption coefficients (Kd) using selected soil properties.

Pesticide soil/solution distribution coefficients ( Kd values), commonly referred to as pesticide soil sorption values, are utilized in computer and decision aid models to predict soil mobility of the compounds. The values are specific for a given chemical in a given soil sample, normally taken from surface soil, a selected soil horizon, or at a specific soil depth, and are normally related to selected soil properties. Pesticide databases provide Kd values for each chemical, but the values vary widely depending on the soil sample on which the chemicals were tested. We have correlated Kd values reported in the literature with the reported soil properties for an assortment of pesticides in an attempt to improve the accuracy of a Kd value for a specific chemical in a soil with known soil properties. Mathematical equations were developed from regression equations for the related properties. Soil properties that were correlated included organic matter content, clay mineral content, and/or soil pH, depending on the chemical properties of the pesticide. Pesticide families for which Kd equations were developed for 57 pesticides include the following: Carboxy acid, amino sulfonyl acid, hydroxy acid, weakly basic compounds and nonionizable amide/anilide, carbamate, dinitroaniline, organochlorine, organophosphate, and phenylurea compounds. Mean Kd values for 32 additional pesticides, many of which had Kd values that were correlated with specific soil properties but for which no significant Kd equations could be developed are also included.

Adsorption↗

Pesticide fate in tropical wetlands of Brazil: an aquatic microcosm study under semi-field conditions.

A contamination of off-site aquatic environments with pesticides has been observed in the tropics, yet only sparse information exists about pesticide fate in such ecosystems. The objective of our semi-field study was to elucidate the fate of alachlor, atrazine, chlorpyrifos, endosulfan, metolachlor, profenofos, simazine, and trifluralin in the aqueous environment of the Pantanal wetland (MT, Brazil). To this aim, water and water/sediment microcosms of two sizes (0.78 and 202 l) were installed in the outskirts of this freshwater lagoon environment and pesticide dissipation was monitored for up to 50 d after application. The physical-chemical water conditions that developed in the microcosms were reproducible among field replicates for both system sizes. Pesticide dissipation was substantially enhanced for most pesticides in small microcosms relative to the large ones (reduced DT(50) by a factor of up to 5.3). The presence of sediment in microcosms led to increased persistence of chlorpyrifos, endosulfan, and trifluralin in the test systems, while for polar pesticides (alachlor, atrazine, metolachlor, profenofos, and simazine) a lesser persistence was observed. Atrazine, simazine, metolachlor, and alachlor were identified as the most persistent pesticides in large water microcosms (DT(50) > or = 47 d); in large water/sediment systems endosulfan beta, atrazine, metolachlor, and simazine showed the slowest dissipation (DT(50) > or = 44 d). A medium-term accumulation in the sediment of tropical ecosystems can be expected for chlorpyrifos and endosulfan isomers (11-35% of applied amount still extractable at 50 d after application). We conclude that the persistence of the studied pesticides in aquatic ecosystems of the tropics is not substantially lower than during summer in temperate regions.

Brazil↗

Evaluation of common organic solvents for gas chromatographic analysis and stability of multiclass pesticide residues.

In this study, we evaluated the suitability of six common organic solvents for gas chromatographic (GC) analysis of pesticides. Three of these, acetone, acetonitrile (MeCN) and ethyl acetate (EtAc), represent extraction solvents commonly used in multiresidue methods for determination of pesticides in produce. The other three, isooctane, hexane and toluene, often serve as exchange solvents before a GC analysis. An ideal solvent for GC analysis of multiclass pesticide residues should be compatible with: the analytes, sample preparation, and GC analysis. This study addresses each aspect with emphasis placed on stability of selected pesticides in the given solvents. In this respect, the exchange solvents proved to be superior to the more polar extraction solvents. Degradation of N-trihalomethylthio fungicides (e.g., captan, folpet, dichlofluanid) in MeCN was observed only in certain lots of the tested MeCN, but even if it occurred, the stability of these analytes as well as that of dicofol and chlorothalonil was dramatically improved by the addition of 0.1% (v/v) acetic acid. Dicofol and chlorothalonil were also unstable in acetone, and pesticides with a thioether group (e.g., fenthion, disulfoton) degraded in the tested EtAc. Formation of isomers of certain pyrethroids (deltamethrin, lambda-cyhalothrin) was recorded in the chromatograms from MeCN and acetone solutions, but this effect more likely occurred during the GC injection than in solution. For several reasons, MeCN was found to be the most suitable solvent for extraction of a wide polarity range of pesticide residues from produce. After acidification, the stability of problematic pesticides in MeCN is acceptable, and MeCN can also serve as a medium for GC injection; therefore solvent exchange is generally not required before GC analysis. If sensitivity is an issue in splitless injection, then toluene was demonstrated to be the best exchange solvent due to its miscibility with MeCN and stronger responses of relatively more polar pesticides (e.g., acephate, methamidophos) as compared to hexane and isooctane.

Organic Chemicals↗

Validation study on 660 pesticide residues in animal tissues by gel permeation chromatography cleanup/gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry.

A new method using gel permeation chromatography (GPC) cleanup followed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS-MS) has been established for quantitative determination of 437 pesticide residues in animal tissues such as beef, mutton, pork, chicken, and rabbit. Based on an appraisal of the characteristics of both GC-MS and LC-MS-MS, validation experiments were conducted for 660 pesticides. In the method, 10 g animal samples were mixed with 20 g sodium sulfate and extracted with 35 mL of cyclohexane+ethyl acetate (1+1) twice by blender homogenization, centrifugation, and filtration. Evaporation was conducted and an equivalent of 5 g sample was injected into a 400 mm x 25 mm S-X3 GPC column, with cyclohexane+ethyl acetate (1+1) as the mobile phase at a flow rate of 5 mL/min. The 22-40 min fraction was collected for subsequent analysis. For the 368 pesticides determined by GC-MS, the portions collected from GPC were concentrated to 0.5 mL and exchanged with 5 mL hexane twice. For the 69 pesticides by LC-MS-MS, the portions collected from GPC were dissolved with acetonitrile+water (60+40) after taking the extract to dryness with nitrogen gas. In the linear range of each pesticide, the correlation coefficient was r > or = 0.98, exceptions being dinobuton, linuron, and fenamiphos sulfoxide. At the low, medium and high three fortification levels of 0.2-4800 microg/kg, recoveries fell within 40-120%, among which 417 pesticides recoveries between 60% and 120%, accounting for 95%, 20 analytes between 40% and 60%, accounting for 5%. The relative standard deviation was below 28% for all 437 pesticides. The limits of detection for the method were 0.2-600 microg/kg, depending on each pesticide.

Animals↗

Determination of several pesticides in water by solid-phase extraction, liquid chromatography and electrospray tandem mass spectrometry.

The analysis of pesticides in water samples is a problem of primary concern for quality control laboratories due to the toxicity level of these compounds and their public health risk. In order to evaluate the impact of pesticides in the Lisbon drinking water supply system, following the requirements of the European Union Directive 98/83/EC, we developed and validated an analytical method based on the combination of solid-phase extraction with liquid chromatography and tandem mass spectrometry. In this work, several pesticides were studied: imidacloprid, dimethoate, cymoxanil, carbendazime, phosmet, carbofuran, isoproturon, diuron, methidathion, linuron, pyrimethanil, methiocarbe, tebuconazole and chlorpyrifos. Several parameters of the electrospray source were optimized in order to get the best formation conditions of the precursor ion for each pesticide, namely capillary and extractor voltage, cone voltage, cone gas flow rate and desolvation gas flow rate. After optimization of the collision cell energy of the triple quadrupole, two different precursor ion-product ion transitions were selected for each pesticide, one for quantification and one for qualification, and these ions were monitored under time-scheduled multiple reaction monitoring (MRM) conditions. The selection of specific fragment ions for each pesticide guarantees a high degree of selectivity as well as additional sensitivity to quantify trace levels of these pesticides in water samples. This method showed excellent linearity ranges for all pesticides, with correlation coefficients greater than 0.9989. Determination limits (between 0.0041 and 0.0480 microg/L), precision (RSD <9.18%), accuracy and recovery studies in several water samples using solid-phase extraction were also performed.

Chromatography, Liquid↗

Pesticide exposure and lung cancer mortality in Leningrad province in Russia.

This study was carried out to examine the association between pesticide exposure and lung cancer mortality. We conducted an autopsy based case-control study in Leningrad Province in Russia. A total of 540 lung cancer cases and 582 controls were identified among subjects who had died in the hospitals of the Leningrad province between 1993 and 1998. Using work history records, we assessed exposure to pesticide at the level of industry and job title. Unconditional logistic regression was used to calculate adjusted odds ratio for pesticide exposure and lung cancer mortality. There was no association between ever exposure to pesticide and lung cancer mortality overall (odds ratio=1.06, 95% confidence interval=0.82-1.36) and in both men (odds ratio=1.11, 95% confidence interval=0.84-1.46) and women (odds ratio=0.74, 95% confidence interval=0.37-1.46). We observed no statistically significant odds ratio by duration of pesticide exposure, intensity of pesticide exposure, and cumulative pesticide exposures with lung cancer mortality in both smokers and nonsmokers. Odds ratio also did not differ when the analysis was restricted to individuals who had exposure data with high confidence scores. Our findings suggest no associations between pesticide exposures and mortality of lung cancer in the population of the Leningrad province in Russia that deserves further evaluation.

Aged↗

Pesticide prioritization for a case-control study on childhood leukemia in Costa Rica: a simple stepwise approach.

Multiple exposures and rapidly changing use patterns are obstacles for adequate recall of pesticide exposures in epidemiologic studies. We present a simple stepwise approach for prioritization of pesticides as part of the exposure assessment strategy in an ongoing case-control study on pesticides and childhood leukemia in Costa Rica. Pesticide imports between 1977 and 2000, approximately the pertinent exposure period, were surrogates for use data. In the first phase, 323 active ingredients were identified, of which 219 were eliminated based on low usage and absence or negative results in a preliminary search in three major toxicity databases. In the second phase, the remaining 104 pesticides underwent scoring for their toxicodynamic potential (TDP) with regard to carcinogenicity, mutagenicity, and teratogenicity, weighted in this order. Bioavailability was assessed when TDP was multiplied by a weight for persistence and bioaccumulation, producing the intrinsic toxic potential (ITP). ITP was multiplied by an index of quantity (QI) of pesticide used in the exposure period, resulting in a weighted toxic potential (WTP). The top 25 positions in each of the four rankings (TDP, ITP, QI, and WTP) yielded together 64 highest-priority pesticides. This prioritization process has to be complemented with a further breakdown into crop-, time-, and biocide-specific shortlists to achieve a recall tool suitable for developing countries. Different parameters for prioritization assure inclusion of all relevant pesticides with regard to toxicity and bioavailability. The method contributes to cancer epidemiology in developing countries with access to basic use data and the Internet. The method is adaptable to other health outcomes.

Agriculture↗

Pesticide poisoning in domestic animals and livestock in Austria: a 6 years retrospective study.

A 6 years retrospective study of pesticide poisonings in domestic animals and livestock from 1999 to 2004 submitted to the Institute for Medical Chemistry, University of Veterinary Medicine, Vienna in Austria was compiled and analysed. Totally 380 pesticide analysis requests were referred by veterinary practitioners, from the Institute for Pathology of the above university, by regional and central governments as well as local police departments and district administrations, animal protectionist groups, public health authorities and private clients. Among the total number of suspected samples for pesticides, 175 (46.1%) cases were found positive to contain pesticides of various kinds. Among the pesticides found, carbamate insecticides were most prominent, representing 50.3% of the total positive cases. These compounds were followed by rodenticides-anticoagulants with 18.9% of the positive results, by organophosphate insecticides 5.1%, and by the rodenticides-nonanticoagulant 3.4%, the other 22.3% included molluscicides, herbicides, etc. In totally 225 animals, 123 animals were found positive for pesticide intoxication, among them 47.2% were dogs, 34.1% were cats 9.8% of other species and 8.9% of unspecified animal samples. The pesticides were characterized by HPLC-techniques using commercially available standards. The aim of this Austrian survey was to determine the incidence and frequency of confirmed pesticide intoxications in animals in Austria and to emphasize its relevance in veterinary practice for livestock and domestic animals.

Animals↗

Pesticides as a source of microbial contamination of salad vegetables.

Ten commercially available pesticides (insecticides, herbicides and fungicides), used during the production of vegetable produce, were examined as potential sources of microbial contaminants. As purchased, none of the pesticides showed the presence of viable microorganisms (< 5 CFU/ml). Using an agar plate diffusion assay, they did not inhibit a range of bacteria of spoilage and public health significance on vegetable produce. After reconstitution in sterile water to their recommended concentration, two of the pesticides supported the survival and growth of inoculated species of Pseudomonas, Salmonella and Escherichia coli. Listeria monocytogenes did not survive after inoculation into any of the pesticides. Pesticides were reconstituted in different sources of agricultural water (bore, dam and river) and examined for survival and growth of microorganisms naturally present in these waters. On storage at 30 degrees C for 48 h, nine of the pesticides supported the growth of bacterial species present in these waters. Predominant species in the pesticide solutions, before and after storage, varied according to the source, but species of Pseudomonas, Acinetobacter and Aeromonas and various coliforms exhibited significant growth. Unless managed properly (reconstituted in potable water, and used without lengthy storage), pesticides could contribute to the microbial load of vegetable produce, thereby affecting their shelf-life and public health safety.

Bacteria↗