Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PESTICIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMed2003

Comparative toxicity and biochemical responses of certain pesticides to the mature earthworm Aporrectodea caliginosa under laboratory conditions.

This study was conducted to investigate the toxicity of aldicarb, cypermethrin, profenofos, chlorfluazuron, atrazine, and metalaxyl toward mature Aporrectodea caliginosa earthworms. The effects of the LC(25) values of these pesticides on the growth rate in relation to glucose, soluble protein, and activities of glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), acid phosphatase (AcP), and alkaline phosphatase (AIP) were also studied. The results showed that aldicarb was the most toxic of the tested pesticides, followed in order by cypermethrin, profenofos, chlorfluazuron, atrazine, and metalaxyl. A reduction in growth rate was observed in all pesticide-treated worms, which was accompanied by a decrease in soluble protein and an increase in transaminases and phosphatases. Relationships between growth rate, protein content, transaminases, and phosphatases provided strong evidence for the involvement of pesticidal contamination in the biochemical changes in earthworms, which can be used as a bioindicator of soil contamination by pesticides.

Animals↗
PubMed1996

Fate and impact of pesticides applied to potato cultures: the Nicolet River basin.

The fate of cash-crop (potato) pesticides was monitored from the fields on which they were applied to the nearby streams. The investigation took place in the Nicolet River basin in the province of Quebec, Canada. The main pesticides under study were aldicarb, fenvalerate, metribuzin, and phorate. Aldicarb was never detected in any of the samples. The other pesticides were all detected in soils at low concentrations. Only fenvalerate and metribuzin were detected in tile drain. Metribuzin concentrations of up to 0.25 microgram/g were detected in the soil giving rise to a concentration of 1.3 micrograms/liter in tile drain and 47.1 micrograms/liter in surface runoff. Low concentrations of metribuzin up to 0.41 microgram/liter were detected in the nearby streams. The CREAMS model simulating pesticide movement in the fields overestimated metribuzin losses in the runoff at a concentration of 107 micrograms/liter. The subsurface EXPRES model using a PRZM time series adequately estimated a metribuzin field subsurface runoff concentration of 0.5 microgram/liter. According to the Canadian Water Quality Guideline for the protection of aquatic life, the concentrations of pesticides found in surface waters of this potato-growing region of Quebec do not have a potential to impact on the aquatic life in these systems.

Aldicarb↗
PubMed1999

Environmental conditions and pesticide pollution of two coastal ecosystems in the Gulf of California, Mexico.

In December 1997 and April and September 1998, water temperature, salinity, dissolved oxygen, nutrients, chlorophyll, and pesticide residues were determined in two coastal ecosystems of Sinaloa, NW Mexico: Ensenada del Pabellón and Bahía de Santa María. These two are considered to be among the greatest shrimp producers in the region. Temperature, salinity, and dissolved oxygen were similar to those of other ecosystems of this region: high temperatures and salinity in spring and summer (dry season) and lower in winter and the rainy season. Levels of nitrites and phosphates and chlorophyll concentration were relatively higher than those of other ecosystems nearby, probably due to fertilizers used in the agricultural lands surrounding the water bodies studied. The pesticides more frequently detected were BHCalpha, aldrin, endosulfan and parathion. In some cases, pesticides forbidden by Mexican regulations were detected. These results indicate that the ecosystems studied are in a warning condition, because severe biochemical and physiological alterations have been reported in crustaceans exposed to pesticides. Therefore these pesticides could be one cause of the slow growth, diverse pathologies, and mortality in shrimp that have been reported in recent years.

Animals↗
PubMed2002

Differential sensitivity of two green algae, Scenedesmus obliqnus and Chlorella pyrenoidosa, to 12 pesticides.

Growth-inhibiting tests were carried out for 12 pesticides (including 11 fungicides: fosetyl-aluminum, benomyl, metalaxyl, iprodione, dimetachlone, carbendazim, thiophanate-methyl, bismerthiazol, procymidone, zineb, chlorothalonil, and the acaricide abamectin) in the green algae Chlorella pyrenoidosa and Scenedesmus obliqnus and the differential sensitivities of the two green algae to those pesticides were compared. The results indicate that the acute toxicity of benomyl to C. pyrenoidosa and S. obliqnus is the highest among all of the pesticides tested and is close to that of the photosynthesis-inhibiting herbicides atrazine, simazine, and chlorotoluron. Meanwhile, algal species vary widely in their response to the pesticides. The results demonstrated that there was a differential response to various pesticides by the two species of algae and that the sensitivity of various species of algae exposed to chlorothalonil varied by nearly two orders of magnitude; sensitivity to thiophanate-methyl varied by more than one order. Investigations using different algal species as test organisms have demonstrated that algae vary greatly in their response to chemicals. Differential sensitivity of green species to the compounds could induce species shifts within communities.

Biological Assay↗
PubMed1997

Cytogenetic monitoring of pesticide sprayers.

The induction of chromosome aberrations, micronuclei, and sister-chromatid exchanges (SCEs) was examined in cultured lymphocytes of 27 vineyard growers exposed to pesticides. Cytogenetic examinations were performed during the prespraying period, a month after spraying, and at the end of the spraying season. For comparison purposes, the same cytogenetic monitoring program was applied to two control groups. The first consisted of 15 individuals from a nearby town, and the second consisted of 20 volunteers living 200 km from the vine-growing area (reference control group). A positive, though low statistically significant (P < 0.017) difference in the yield of unstable chromosomal aberrations in exposed sprayers was observed compared with both control groups during the prespraying period. The mean group value of micronuclei in exposed workers averaged 5.41 per 1000 binucleated cells, with individual means ranging from 0 to 15. In both control groups, the yield of micronuclei averaged 5.09 per 1000 binucleated cells, with individual means ranging from 1 to 10. No statistically significant (P < 0.5) differences in yield of micronuclei were found in exposed subjects compared with both control groups. Significant individual variation (F = 14.09, P < 0.000) in SCE frequency was observed in exposed subjects, as well as in both control groups (F = 14.09, P < 0.000). A month after spraying, the average incidence of unstable aberrations in pesticide sprayers was 0.22%, and the yield of micronuclei averaged 17.78 per 1000 binucleated cells, with individual means ranging from 7 to 28. The incidence of micronuclei a month after spraying in exposed subjects was elevated (statistically significant at P < 0.01) in comparison with the prespraying period, while the difference in the yield of chromosomal aberrations in exposed subjects was insignificant (P < 0.5). At the end of the spraying season, the average incidence of unstable aberrations in exposed subjects was 0.79%, and the yield of micronuclei averaged 39.92 micronuclei per 1000 binucleated cells, with individual means ranging from 21 to 62. The appearance of more than one micronucleus per binucleated cell was related to the results on chromosome aberrations. The frequencies of chromosomal aberrations and micronuclei were significantly higher (P < 0.001, P < 0.000) in the exposed group than in their matched control groups. The yield of micronuclei in pesticide sprayers at the end of the season was higher than expected with respect to chromosomal aberration frequency, which provides some evidence that some of the micronuclei are induced by the spindle-inhibiting effects of pesticides. A statistically significant (P < 0.003) difference in micronuclei in the first control group was observed compared with the reference control group at the end of the spraying season. With respect to the incidence of micronuclei in the control group in the vine-growing area, a poor but positive correlation (r = 0.074, P < 0.104) with duration of the spraying season was found, which is probably due to airborne pesticides in the vine-growing area. SCE frequencies of the workers' lymphocytes were not significantly changed due to the exposure. The yield of aberrations as well as that of micronuclei in exposed subjects correlated positively (r = 16, P = 0.016) with duration of exposure.

Adult↗
PubMed1994

Assessment of the reproductive and developmental toxicity of pesticide/fertilizer mixtures based on confirmed pesticide contamination in California and Iowa groundwater.

Pesticides and fertilizers, as used in modern agriculture, contribute to the overall low-level contamination of groundwater sources. In order to determine the potential of pesticide and fertilizer mixtures to produce reproductive or developmental toxicity at concentrations up to 100 x the median level found in groundwater, we prepared and studied two mixtures of pesticides and a fertilizer (ammonium nitrate). One mixture containing aldicarb, atrazine, dibromochloropropane, 1,2-dichloropropane, ethylene dibromide, and simazine plus ammonium nitrate was considered to be a representative of groundwater contamination in California (CAL). The other, containing alachlor, atrazine, cyanazine, metolachlor, metribuzin, and ammonium nitrate, simulated groundwater contamination in Iowa (IOWA). Each mixture was administered in the drinking water of either Swiss CD-1 mice during a Reproductive Assessment by Continuous Breeding study or pregnant Sprague-Dawley rats (gd 6-20) at three dose levels (1x, 10x, and 100x) where 1x was the median concentration of each pesticide component as determined in the groundwater surveys in California or Iowa. Unlike conventional toxicology studies, the purpose of this study was to evaluate the health effects of realistic human concentrations. Thus, the testing concentrations are probably well below the maximally tolerated dose. Propylene glycol was used as the solubilizer for the pesticides in drinking water formulations in both studies. In the reproductive study, neither mixture caused any clinical signs of toxicity, changes in food or water consumption, or body weight in either F0 or F1 mice at doses up to 100x the median groundwater concentrations. There were no treatment-related effects on fertility or any measures of reproductive performance of either the F0 or the F1 generation mice exposed to either CAL or IOWA at up to 100x. Similarly, measures of spermatogenesis, epididymal sperm concentration, percentage motile sperm, percentage abnormal sperm, and testicular and epididymal histology were normal. In the developmental study, CAL- or IOWA-exposed females did not exhibit any significant treatment-related clinical signs of toxicity. No adverse effects of CAL or IOWA were observed for measures of embryo/fetal toxicity, including resorptions per litter, live litter size, or fetal body weight. CAL or IOWA did not cause an increased incidence of fetal malformations or variations. In summary, administration of these pesticide/fertilizer mixtures at levels up to 100-fold greater than the median concentrations in groundwater supplies in California or Iowa did not cause any detectable reproductive (mice), general, or developmental toxicity (rats).

Animals↗
PubMed1993

Infant formulas: evidence of the absence of pesticide residues.

Concern about the effect of potential pesticide residues on the safety of the U.S. food supply has led to extensive modeling and projections of worst-case scenarios. Many risk assessment models project risk based on an assumption of the presence of pesticide residues at the tolerance level or at a level equivalent to the limit of analytical detectability. Often, actual residue data, and the variability of analytical detection limits, are ignored in favor of simpler models. Data presented here demonstrate the absence of detectable levels of pesticides in infant formula. The range of detection limits of analytical methodology employed also are presented. A rationale for the absence of pesticide residues in infant formulas derived from plant and animal sources is presented which obviates worst-case scenario calculations of risk based on pesticide residue tolerance levels or method detection limits.

Food Handling↗
PubMed1995

A review of the acceptable daily intakes of pesticides assessed by WHO.

Over the past three decades, WHO has evaluated and reevaluated, through the Joint FAO/WHO Meeting on Pesticide Residues, 230 pesticides. The acceptable daily intakes (ADIs) of these pesticides are analyzed along with their scientific bases. In most cases, the evaluation process was consistent with the stated general principles and procedures of JMPR. However, the safety factors used in allocating the ADIs of several pesticides seem to be inconsistent with the severity of the toxicity, and thus, may require further consideration. These chemicals are abamectin, dinocap, procymidone, chlormequat, ethion, glyphosate, fentin hydroxide, and fentin compounds. In addition, pesticides that were evaluated many years ago, e.g., bromomethane, might merit a reevaluation in light of any relevant recent data.

Animals↗
PubMed1999

The impact of rice pesticides on the aquatic ecosystems of the Sacramento River and Delta (California).

Since the early 1980s, when molinate was demonstrated to have killed carp in agricultural drains, an intensive research effort has been undertaken to assess the impact of rice pesticides on aquatic ecosystems in the Sacramento River and Delta. No impact has been found that can be clearly attributed to rice pesticides. However, the rice insecticides methyl parathion and carbofuran, and probably also bufencarb, reached levels in the River and Delta that, based on laboratory bioassays, would have been toxic to aquatic microinvertebrates and, in the case of bufencarb, to early life stages of striped bass. Reductions in microinvertebrate populations could have impacted higher organisms in the aquatic food chain such as striped bass and chinook salmon. Bufencarb was not used after 1981. Since then, changes in the management of the remaining rice pesticides have resulted in dramatic decreases in the levels of these chemicals in the River and Delta. Levels achieved today have no known toxicity to aquatic organisms. As releases of rice pesticides were reduced to achieve nontoxic levels in the River and Delta, however, commensurate recoveries of striped bass and chinook salmon did not occur, suggesting that rice pesticides may have had little or no role in the decline of these species.

Animals↗
PubMed1992

Assessing human exposures to pesticides.

Pesticide use is inevitably associated with chemical exposures that range from inferred nondetectable levels to easily measurable ones using sensitive, readily available analytical tools. Whether these exposures are of any biological significance is determined by duration, dose, and biological reactivity. The overwhelming majority of human exposures occur in a diverse chemical milieu of a nutritive substances and are of no known significance. Technologies that minimize human chemical exposures and maximize pesticide effectiveness are favored. The risk characterization process is ideally suited to assist decision makers concerning the protection of human health and evaluation of agricultural tools. It is the best means available to balance the review of pesticide impacts on health and agriculture. Regulators must be cautious to acknowledge the relative rather than absolute nature of the risk characterization process. Workplace biological monitoring must become more commonplace as a means to evaluate the chemical exposure potential of various work tasks and greater attention must be given to the biological validation of methods. Earlier needs for data to develop workplace hygiene strategies have been replaced in recent years by demands of the risk assessment process, which utilizes direct estimates of exposure and absorbed dose. Animal models, no matter how attractive, are not presently a substitute for human experience. Opportunities to gather more information on human experience associated with pesticide exposures must be more aggressively identified and pursued. Only a very small time lag should exist between identification of pesticide metabolites in rats and evaluation of metabolic similarities in humans. At the present levels of analytical sensitivity, most of our current uncertainty about the extent of worker exposure and patterns of metabolism between species can be at least clarified with the cooperation of persons who are exposed during normal day-to-day activities in the workplace. Only with better human data will the risk assessment process warrant greater reliance in decision making concerning our chemical exposures and human experience.

Environmental Exposure↗
PubMed1996

Persistent pesticides in Mexico.

As part of the recent increase in the international interest in persistent organic pollutants and their environmental and health hazards, it was found that although most of them have been severely controlled in developed countries, in most developing countries--including Mexico--their import, use, and in some cases production have continued up to the present without sufficient or adequate controls. Despite the large and continuing use of persistent organic chemicals in Mexico in agriculture, public health, and industry, data on their import, production, use, disposal, and the presence of their residues in the environment, food, and human tissues are extremely scarce and widely dispersed. This review is devoted only to the use of persistent pesticides in Mexico; it is the first effort to locate, gather, and analyze this information and to summarize and discuss the past and current situation of the control of these chemicals in Mexico. This review discusses the general background for the use of these pesticides in the country, including historical development, the reasons for substitution by less persistent products in crops intended for export, and the undesirable effect of this substitution on the health of migratory agricultural workers. The current status of the legal framework for the control of pesticides in Mexico is presented with emphasis on its slow and haphazard development; the legal, technical, and administrative reasons for the insufficient enforcement and oversight of the existing regulations and standards are highlighted. The low priority of this research area for the Mexican science and technology authorities and the negative consequences of this low priority on the existence of sufficient reliable data on pesticide residues in the environment and humans in Mexico are also discussed. The available data on production and uses of persistent pesticides in Mexico are presented, and the existing information on their residues in the environment, biota, food, and human tissues in the country is summarized; maps with the location of the main studies are included to stress the lack of information for most of the country, especially for remote areas and regions of agriculture devoted to crops for local, domestic, or self-consumption. The major characteristics of these studies are discussed in specific sections and, on this basis, a general comment on the current situation and forecast for the near future is made. The conclusions summarize the information presented, with particular emphasis on the need to improve and update the legal framework and strengthen the technical and administrative infrastructure essential for the oversight and control of the regulations. The urgency of carrying out new studies, in particular interdisciplinary studies, to establish the current pattern for pollution by these chemicals in Mexico is stressed.

Animals↗
PubMed1992

Agricultural pesticide exposure data bases for risk assessment.

For pesticide registration, data on toxicity and on occupational exposure are required. In the smaller countries, such as The Netherlands, only a small number of studies on exposure will be available for a proper risk assessment. Therefore, the primary data have to be obtained mainly from the literature. In this review the exposure data available in the formally published literature and from a few Dutch reports for mixing, loading, and application of pesticides are considered for the development of generic/surrogate data bases with which for a specific case (e.g., a new pesticide) the exposure can be estimated for use in a first step of risk assessment. The general aspects of the determination of exposure to pesticides under field conditions are considered, as well as the published proposals for generic data bases. It is concluded that the development of data bases is possible in principle, although in many cases, depending on the type of technique for mixing/loading and application, not enough data are available. Data bases on re-entry have not been proposed in the literature, although many studies on exposure after reentry have been reported. In view of the fact that in some cases the mixer/loader is not the same person as the applicator and considering the different hygienic approach that may be needed for diminishing exposure during these types of work, data on exposure during mixing and loading and on exposure during application were considered separately whenever possible or reasonable. Since data on exposure may vary considerably in daily agricultural practice and since the data sets are in most cases relatively small and not homogeneous, it is impossible to calculate statistically valid means or percentiles. Therefore, estimates have been made which are called indicative values. For risk assessment such estimates, to be used in a first approximation without further specific knowledge on chemical properties of the pesticide, need to be high percentiles, since all 'normal' situations have to be considered and a high degree of worker protection should be achieved. From the data, indicative 90th percentiles of exposure have been estimated and expressed as amount of formulated product per hour of mixing and loading and expressed in amount of spray liquid per hour application. These 90th percentiles are presented in Table 9. As can be seen from Table 9, for various application techniques no data on exposure were available in the open literature, or the number of published data was considered insufficient to obtain indicative surrogate levels that can be used in registration procedures.(ABSTRACT TRUNCATED AT 400 WORDS)

Agriculture↗
PubMed1992

Pesticide protective clothing.

In looking into future directions of "protective clothing" for pesticide users, the final EPA ruling scheduled for release in June 1992 (Smith personal communication) places the majority of its recommendations on the label. Therefore, it will be up to pesticide manufacturers to provide protective clothing information on their products labels. Research on protective clothing continues to show variations due to fabric characteristics of fiber content, fabric construction and finish. These variabilities are compounded by variation s due to pesticide formulation and pesticide chemical and are further compounded by field studies vs laboratory simulations. With hundreds of fabric variations compounded by the thousands of chemical compounds and formulation variations, the consumer cannot be expected to make proper decisions regarding protective clothing. The user of the product does not have the knowledge to select the appropriate clothing. Manufacturers must supply this information, but they must also have data to support recommendations of their clothing for pesticide protection. This shifts the responsibility for recommending adequate protective clothing, as well as the concern for product liability, to the manufacturer.

Humans↗
PubMed1992

Acute pesticide morbidity and mortality: California.

The California Pesticide Illness Surveillance Program collects, investigates, abstracts, and records reports received from physicians. A minority of the reports are received through the county health officers who are notified by physicians under a state requirement for reporting pesticide-caused conditions. Most of the cases are identified by review of workers' compensation records. All the cases identified are investigated by the agricultural commissioners of the counties where exposure occurred. The investigation reports are reviewed and abstracted by staff of the Worker Health and Safety Branch of the California Department of Pesticide Regulation, California Environmental Protection Agency (Cal/EPA). The crucial determination is assessment of the degree of relationship between the exposure and subsequent disease: definite, probable, possible, unlikely, or unrelated. In most years, the number of cases investigated has been between 2,500 and 3,000. Excluding antimicrobials, the number of cases found after investigation to have a definite, probable, or possible relationship with pesticide exposure has ranged from 970 (in 1989) to 1,372 (in 1988). Cases involving antimicrobials rarely were reported prior to 1987. In that year, surveillance staff began reviewing workers' compensation records personally, with the specific goal of identifying antimicrobial cases. Since then, antimicrobials have been found to account for 746-813 cases annually, primarily involving splashes and squirts to the eye and inhalation of fumes or vapors. Numbers of case reports from agricultural situations have varied irregularly, driven by small numbers of episodes concerning multiple individuals. Variability in numbers of cases involving the skin has depended almost entirely on variation in numbers of field worker dermatitis. The most common situation for field worker dermatitis has been summer work in table grapes grown in the southern San Joaquin valley. In the two years since reentry intervals for the acaricide propargite were lengthened, there have been no more major clusters of field worker dermatitis. Although the cases collected by the surveillance program are predominantly occupational, because of dependence on workers' compensation for case identification, most recorded deaths are nonoccupational. Nonoccupational fatalities include suicides, mistaken ingestion of pesticides (especially if stored in food containers), and entry into structures being fumigated. Occupational deaths are less common and more varied. The circumstances of each reported occupational death are summarized above.

California↗
PubMed1992

Comparison of exposure assessment guidelines for pesticides.

The field of exposure assessment of pesticides has become well established in the past decade. Consequently, government agencies and industry groups have identified the need for guidelines for conducting studies that assess mixer/loader/applicator exposure to pesticides, as well as the exposure of individuals to residues. This paper reviews guidelines on mixer/loader/applicator exposure studies issued by the International Group of National Associations of Manufacturers of Agrochemical Products, the National Agricultural Chemicals Association, the U.S. EPA, and the World Health Organization. Mention is also made of Canadian exposure guidelines in preparation. Also reviewed are two guidelines for conducting indoor occupant exposure studies, one by the National Agricultural Chemicals Association and one by Health and Welfare Canada. The only available guideline (EPA) on assessing pesticide exposure to workers upon reentry into treated fields is also reviewed. These guidelines are reviewed and compared as to criteria for requirements of exposure studies, methodologies recommended for dermal, inhalation, and biological monitoring, quality assurance and quality control, the use of surrogate data, data reporting, and exposure calculations. From this comparison, it is evident that there has been little significant progress in the area of methodologies used for dermal exposure monitoring. The use of patches as suggested by Durham and Wolfe (1962) is still accepted and widely used, despite its limitations. However, relatively recent research in this area has shown that the fluorescent tracer technique (Fenske et al. 1986a,b) and use of full-body dosimeters may help in overcoming some of these limitations. The tracer technique is mentioned in the EPA guidelines and full-body dosimeters are addressed by EPA, WHO, and NACA. Biological monitoring can also overcome many of the limitations of passive dosimetry, but all guidelines stress the need for extensive knowledge of the pharmacokinetics and metabolism of the pesticide before this approach can be used. Rapid advancement has been made in quality assurance/quality control and analytical techniques. This has increased the level of confidence placed in exposure estimates and is evidenced by the detailed requirements of quality assurance and quality control in most of the guidelines reviewed. Guidelines on conducting indoor occupant exposure studies deal extensively with methodologies for collecting residue samples, but do not make concrete recommendations for estimating human exposure based on these residues. More research is required before the subject can be adequately dealt with in guidelines. It is encouraging that this research is being coordinated among industry, academia, and government. Further research is also needed in determining exposure to pesticides during reentry into treated areas in order to develop further guidelines.(ABSTRACT TRUNCATED AT 400 WORDS)

Air Pollution, Indoor↗
PubMed1993

Frictional transition of pesticides from protective clothing.

Frictional transition of pesticides, the transition of the dried pesticide due to rubbing, from protective clothing was investigated by using an AATCC standard crockmeter. One insecticide (carbaryl) and two herbicides (atrazine and metolachlor) were studied, together with three protective clothing materials [cotton, polyester, and polyester/cotton (65/35) blend] and three crock fabrics (cotton, nylon, and silk). The effects of the properties of pesticide, fabrics, water, and perspiration on the frictional transition are discussed. The experiment showed that up to 12% of the pesticide could transfer from contaminated protective clothing to the skin through rubbing. Choosing the right materials for protective clothing and underwear would greatly decrease the frictional transition of the pesticide.

Laundering↗
PubMedDate not supplied

Genetic toxicity of a mixture of fifteen pesticides commonly found in the Italian diet.

To determine the toxicological effects of complex mixtures of pesticides, we obtained data on 100 pesticide residues in common foods of central Italy. Fifteen pesticides were more regularly detected at higher levels (dithiocarbamates, benomyl/carbendazim, thiabendazole, diphenylamine, chlorthalonil, procymidone, fenarimol, chlorpropham, vinchlozolin, methidathion, chlorpyriphos-ethyl, parathion-methyl, parathion, chlorfenviphos, pirimiphos-ethyl). Using itemized data on daily food consumption in Italy, we calculated that the average exposure for an adult subject was 716 micrograms/day, ranging from 148 micrograms of dithiocarbamates to 1 microgram of pirimiphos-ethyl. We made a mixture of these 15 pesticides at concentrations proportional to the ratio determined in foods and tested it with the Salmonella-microsome assay, with and without metabolic activation with PCB-induced rat liver S9. No mutagenic activity was observed at concentrations up to 500 micrograms/plate. We also tested the same mixture at concentrations ranging from 0.1 to 20 micrograms/ml on human lymphocytes in vitro, and observed a slight but statistically significant increase in sister-chromatid exchanges at 1 microgram/ml. We also administered the mixture in corn oil by gavage to Wistar rats at doses of 1, 10, and 100 micrograms/kg. After 24 hr the ratio between bone marrow polychromatic and normochromatic lymphocytes (a sign of cellular toxicity) was decreased by the exposure, but we did not observe a significant increase in the frequency of micronuclei. We conclude that the pesticide mixture did not have appreciable genotoxic activity in the assays used.

Adult↗
PubMed1980

Safety effectiveness of pesticide mixing-loading and application equipment used in 1976.

The effectiveness of currently used pesticide mixing-loading and application equipment in preventing workers from being exposed to cholinesterase (ChE) inhibiting pesticides was measured. Blood samples from workers involved in the application of pesticides in Monterey and Imperial counties of California were analyzed for ChE activity. The analyses indicated that only the mean red cell activity of mixer-loaders was significantly less than controls. Seasonal variations in ChE activity were noted for workers in Imperial County between January and August. These variations were apparently related to the toxicity of the pesticides used. A prototype, closed-transfer system used in Imperial County did not substantially reduce pesticide residues in the air around mixing-loading sites or prevent a reduction in ChE activity over that of open-transfer systems. This was attributed to inadequate training in the use of the new equipment on the part of the mixer-loaders and improperly maintained equipment. A protytype closed-transfer system used in Monterey County appeared to give some protection to mixer-loader applicators during the application season; however, the blood ChE activities of two mixer-loaders using another prototype closed system in Monterey County were severely depressed.

Agricultural Workers' Diseases↗