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BACKGROUND: Concern about the adverse public health and environmental effects of pesticide use is persistent. Recognizing the importance of surveillance for acute occupational pesticide-related illness, we report on surveillance for this condition across multiple states. METHODS: Survey data collected between 1998 and 1999 were obtained from the seven states that conduct acute occupational pesticide-related illness surveillance as part of the Sentinel Event Notification System for Occupational Risks (SENSOR) program. Data were collected by these state programs in a standardized manner and analyzed. Acute occupational pesticide-related illness incidence rates for those employed in agriculture and those employed in non-agricultural industries were also calculated. RESULTS: Between 1998 and 1999, a total of 1,009 individuals with acute occupational pesticide-related illness were identified by states participating in the SENSOR-pesticides program. The mean age was 36 years, and incidence rates peaked among 20-24 year-old workers. The overall incidence rate was 1.17 per 100,000 full time equivalents (FTEs). The incidence rate among those employed in agriculture was higher (18.2/100,000 FTEs) compared to those employed in non-agricultural industries (0.53/100,000 FTEs). Most of the illnesses were of low severity (69.7%). Severity was moderate in 29.6% of the cases, and high in four cases (0.4%). Three fatalities were identified. Insecticides were responsible for 49% of all illnesses. CONCLUSIONS: Surveillance is an important tool to assess acute pesticide-related illness, and to identify associated risk factors. Our findings suggest that these illnesses continue to be an important occupational health problem, especially in agriculture. As such, greater efforts are needed to prevent acute occupational pesticide-related illness.
In parts of the developing world, pesticide poisoning causes more deaths than infectious diseases. Use of pesticides is poorly regulated and often dangerous; their easy availability also makes them a popular method of self-harm. In 1985, the UN Food and Agriculture Organisation (FAO) produced a voluntary code of conduct for the pesticide industry in an attempt to limit the harmful effects of pesticides. Unfortunately, a lack of adequate government resources in the developing world makes this code ineffective, and thousands of deaths continue today. WHO has recommended that access to highly toxic pesticides be restricted--where this has been done, suicide rates have fallen. Since an Essential Drugs List was established in 1977, use of a few essential drugs has rationalised drug use in many regions. An analogous Minimum Pesticides List would identify a restricted number of less dangerous pesticides to do specific tasks within an integrated pest management system. Use of safer pesticides should result in fewer deaths, just as the change from barbiturates to benzodiazepines has reduced the number of deaths from pharmaceutical self-poisoning.
Epidemiologists frequently rely on self-reported information regarding a variety of exposures including smoking history, medication use, and occupational exposure because other sources of information are either unavailable or difficult to obtain. One way to evaluate the accuracy of self-reported information is through logic checks using other sources. To assess the quality of the self-reported pesticide product use history of 57,311 licensed pesticide applicators in the Agricultural Health Study (AHS), we compared the self-reported decade of first use and total years of use to the year the pesticide active ingredient was first registered for use. We obtained pesticide active ingredient registration information from the United States Environmental Protection Agency (USEPA) and other publicly available sources for the 52 pesticides on the AHS initial questionnaires administered from 1994 to 1997. Based on the registration year, we assessed 19 pesticides for potential inaccuracies regarding duration of use or decade of first use. When calculating potential total years of use, we did not consider the impact of chemicals being removed from the market, since the possibility for continued use existed. The majority of respondents provided plausible responses for both decade of first use and total duration of use. On average, 1% of the subjects overestimated total possible duration of use, ranging from less than 1% for carbofuran and chlorpyrifos to 5% for imazethapyr. Decade of first use was also reasonably reported, although more subjects did not report decade of first use than duration of use, with an average of 6% of subjects missing decade information for an individual chemical. For subjects who reported a decade of first use, 98% gave plausible responses on average, with overestimates highest for cyanazine, introduced in 1971 (6% reported earlier use), and chlorimuron ethyl, introduced in 1985 (7% reported earlier use). This analysis provided the opportunity to consider only one source of potential overreporting of exposure, and while underreporting may have also occurred, we cannot evaluate its role nor the balance between these potential inaccuracies. While we are unable to validate directly the accuracy of a respondent's use of pesticides, this analysis suggests that participants provide plausible information regarding their pesticide use.
Pesticide container handling operations in western Canada were examined to determine the exposure of workers to residual pesticide in sorting, metal-container crushing, metal-container shredding, plastic-container shredding, metal washing, and metal melting. Environmental exposure monitoring and biological monitoring were applied, including measurement of pesticide deposition density on outer clothing (test coveralls and other protective wear), deposition on fabric and gauze patches under the outer clothing, inhalation of airborne pesticide residues, dislodgement of pesticide residues by hand washing, and pre- and postexposure urinary excretion of pesticide (2,4-D). Exposure levels were highly variable; some variability was accounted for by work practices or lapses in protection. The highest levels of exposure were observed for metal washing, metal crushing, and metal shredding; sorting and plastic shredding were intermediate, and metal melting was associated with very little exposure. Urinary 2,4-D excretion, as an indicator of internal dose, correlated most closely with exposure by the inhalation route, and both were highest for metal washing and shredding. Deposition of pesticide on garments was highest for metal crushing. Melting of washed metal does not appear to present a significant hazard of exposure. Recommendations are proposed for the protection of workers emphasizing health and safety guidelines, worker education, personal hygiene, exposure and health monitoring, and record-keeping, and specific recommendations for each process. These recommendations apply to all pesticide container recycling operations except melting of washed metal containers.
Efforts to reduce pesticide-related risks to consumers and farmworkers often neglect the possibility that measures to reduce the target risk may introduce or enhance countervailing risks. These may arise from substitute pesticides or pest-control practices, from increased levels of pests or pest-related hazards, from increased levels of toxic natural pesticides in plants, from increased costs and decreased consumption of health-enhancing fruits and vegetables, or from direct income effects on consumers and farmers. The effect of the countervailing risks may partially or completely offset the reduction in the target risk. A risk-trade-off analysis was conducted of a potential ban on the use of organophosphate and carbamate (OP/Carbamate) insecticides in U.S. agriculture. Although this scenario is extreme, it has the analytic virtue of dispensing with the infinite number of "next-best" OP/Carbamates that might be substituted for specific combinations of crops and pests should only selected uses be banned. The analysis relies on detailed descriptions of the alternative pesticides and pest-control measures that would be used for each of 14 major crops. The effects of pest-control cost changes on prices and consumption and effects on consumer and producer incomes are projected using a general-equilibrium economic model. Several countervailing risks that may be significant were found, including acute toxicity to farmworkers from substitute pesticides, cancer and noncancer risks from substitute pesticides, and mortality induced by changes in disposable income. Other countervailing risks are more difficult to estimate or weigh. Potential increases in natural plant pesticides following an OP/Carbamate ban are discussed but data are lacking to quantify the effects. Changes in diet following the ban have both positive and negative effects, and the ultimate change is difficult to estimate. Although a net risk cannot be estimated, several approaches were illustrated that would be useful in risk-trade-off analyses. Key factors complicating comprehensive analysis of risk/risk trade-offs for pesticides were also identified, including data gaps and shortcomings of current risk assessment methods.
BACKGROUND: Health effects of pesticides have not been well studied in black farmers. We describe agricultural practices and pesticide-related symptoms in North Carolina black and white farmers participating in the Agricultural Health Study. METHODS: Self-administered questionnaires were completed by 891 black and 11,909 white farmers licensed to apply restricted pesticides. Regression models were used to compare characteristics by race. RESULTS: Black farmers reported lower lifetime pesticide use, less use of each class of pesticides (e.g., herbicides, insecticides), less use of high exposure application methods, and fewer pesticide-related symptoms such as headaches or dizziness, skin irritation, chest discomfort and feeling nervous or depressed than did white farmers. CONCLUSIONS: Differences between black and white farmers may be explained by farm characteristics or economics. Despite lower use of pesticides, black farmers may have other work practices that affect exposure and risk.
Epidemiologic studies of possible effects of agricultural environments upon human health suffer from lack of reliable pesticides usage data. The Arkansas Reproductive Health Monitoring System has developed a method for estimating specific pesticides usage annually for sub-county regions, including amounts, application method, and months. This method is applied to 39 regions of 8 central Arkansas counties for 1980-82. The hugh variability of pesticides usage on individual crops demonstrates the inaccuracy likely if general survey estimates are employed. Annual usage of pesticides in a single sub-county region of 53,000 hectares (130,880 land acres) was greater than 1/2 million pounds (248,670 kg) of 60 pesticides, 40 of which were applied during a four month period. The multiplicity and variability of pesticides usage indicate the need for locally developed pesticides data for epidemiologic studies and for combined studies across regions with widely differing agricultural practices.
Although pesticides are used extensively by lawn care and tree service workers, the incidence of pesticide poisonings among this population has never been systematically assessed. This article is a review of suspected and confirmed pesticide poisonings of lawn care and tree service applicators that were reported to the New York State Pesticide Poisoning Registry from 1990 to 1993. Thirty-nine cases were identified, of which 28 satisfied the criteria for a suspected or confirmed poisoning. At the time of the poisoning, the majority of applicators reported the use of more than one class of pesticide. The most common classes of pesticide applied were organophosphates (71%) and herbicides (43%). Twenty-four cases were identified through laboratory reporting. All 24 laboratory tests had been ordered for worker surveillance. Twenty of the reported workers were symptomatic. Personal protective equipment was used routinely by 22 of the 27 applicators for whom information was available. These data suggest that pesticide exposures are occurring among a subset of the lawn care and tree service applicators, despite the reported routine use of safety measures. More rigorous evaluation of the control measures utilized in the lawn care and tree and shrub industry is warranted.
OBJECTIVE: To measure the amounts of pesticide residue in wool grown in Queensland between 1997 and 1999, and to describe the use of pesticides for the control of lice infestations and blowfly strike in Queensland sheep flocks. DESIGN: Pesticide residues were measured in a random sample of wool from Queensland clips offered for sale during 1998 and 1999. Information on pesticide use was obtained from a trace-back postal survey. PROCEDURE: Samples taken from wool lots were tested for the presence and amount of organophosphorus (OP), synthetic pyrethroid (SP) and insect growth regulator pesticides. A questionnaire seeking information on flock characteristics and pesticide use was sent to the manager of each flock from which a wool sample was tested. RESULTS: The mean amount of OP and SP residue was 2.0 and 0.8 mg/kg, respectively. Ninety-five and 98% of wool samples contained < 9 mg/kg and 7 mg/kg of OP and SP residues, respectively. The mean amount of cyromazine, diflubenzuron and triflumuron was 12.7, 5.8 and 13.0 mg/kg, respectively. The amounts of OP, cyromazine and triflumuron residues were greater in wool from flocks located in southern Queensland. CONCLUSION: Most (95%; 95% CI, 92-97%) Queensland wool clips grown between 1997 and 1999 meet the suggested Australian maximum acceptable residue amounts for OP and SP pesticides.
Residues of chlorinated organic pesticide chemicals were commonly found in all diet samples and all food classes within samples except beverages at a daily intake of 0.0014 mg per kilogram of body weight. Meat, fish, and poultry were the major source of pesticide residues and, when combined with dairy products, account for more than half of the intake of chlorinated organic pesticide chemicals. Fruits, garden fruits, and grain foods each accounted for about 10 percent of the intake of chlorinated pesticides. The DDT, its two analogs, dieldrin, lindane, and heptachlor epoxide account for 85 percent of the total intake of chlorinated pesticides. A single pesticide, DDT, accounts for one-third of the total. There was no statistically significant change in frequency or quantities of these compounds during this study. Frequency and quantities of the 14 additional chlorinated pesticides were too low to be meaningful.
We used California's Pesticide Use Report (PUR) and land-use survey data to conduct a simulation study evaluating the potential consequences of misclassifying residential exposure from proximity to agricultural pesticide application in health effect studies. We developed a geographic model linking the PUR with crop location data from land-use surveys to assess the impact of exposure misclassification from simpler exposure models based solely on PUR or land-use data. We simulated the random selection of population controls recruited into a hypothetical case-control study within an agricultural region. Using residential parcel data, we derived annual exposure prevalences, sensitivity, and specificity for five pesticides and relied on the PUR plus land-use model as the "gold standard." Based on these estimates, we calculated the attenuation of prespecified true odds ratios (ORs), assuming nondifferential exposure misclassification. True ORs were severely attenuated a) when residential exposure status was based on a larger geographic area yielding higher sensitivity but low specificity for exposure, in contrast to relying on a smaller area and increasing specificity; b) for less frequently applied pesticides; and c) with increasing mobility of residents among the study population. Considerable effect estimate attenuation also occurred when we used residential distance to crops as a proxy for pesticide exposure. Finally, exposure classifications based on annual instead of seasonal summaries of PUR resulted in highly attenuated ORs, especially during seasons when applications of specific pesticides were unlikely to occur. These results underscore the importance of increasing the spatiotemporal resolution of pesticide exposure models to minimize misclassification.
BACKGROUND: Pesticides, which by their nature are biologically active compounds, continue to raise public concern regarding their possible role as important etiologic agents in the development of human cancer. METHODS: To examine this potential role, the National Cancer Institute of Canada convened an Ad Hoc Panel on Pesticides and Cancer to examine the possible contribution of pesticide exposure, particularly in the general population, to the development of human cancer. RESULTS: The Panel focused primarily on exposure in the general population and reviewed a range of studies that addressed issues related to dietary exposure as well as incidental home and garden uses. In addition, the Panel examined the regulatory framework that exists to safeguard the public from potentially carcinogenic pesticides and also reviewed some potential benefits of pesticide use, including the availability of an abundant and low cost supply of fresh fruits and vegetables as an important strategy in the overall mitigation of cancer risk. CONCLUSIONS: The Panel concluded that it was not aware of any definitive evidence to suggest that synthetic pesticides contribute significantly to overall cancer mortality. The Panel also concluded that it did not believe that any increased intake of pesticide residues associated with increased intake of fruits and vegetables poses any increased risk of cancer. The Panel further concluded, among other things, that tobacco use continues to be the most important preventable cause of cancer and premature mortality and thus is an appropriate focus for cancer control strategy.
The Root Zone Water Quality Model (RZWQM) is a one-dimensional, numerical model for simulating water movement and chemical transport under a variety of management and weather scenarios at the field scale. The pesticide module of RZWQM includes detailed algorithms that describe the complex interactions between pesticides and the environment. We have simulated a range of situations with RZWQM, including foliar interception and washoff of a multiply applied insecticide (chlorpyrifos) to growing corn, and herbicides (alachlor, atrazine, flumetsulam) with pH-dependent soil sorption, to examine whether the model appears to generate reasonable results. The model was also tested using chlorpyrifos and flumetsulam for the sensitivity of its predictions of chemical fate and water and pesticide runoff to various input parameters. The model appears to generate reasonable representations of the fate and partitioning of surface- and foliar-applied chemicals, and the sorption of weakly acidic or basic pesticides, processes that are becoming increasingly important for describing adequately the environmental behavior of newer pesticides. However, the kinetic sorption algorithms for charged pesticides appear to be faulty. Of the 29 parameters and variables analyzed, chlorpyrifos half-life, the Freundlich adsorption exponent, the fraction of kinetic sorption sites, air temperature, soil bulk density, soil-water content at 33 kPa suction head and rainfall were most sensitive for predictions of chlorpyrifos residues in soil. The latter three inputs and the saturated hydraulic conductivity of the soil and surface crusts were most sensitive for predictions of surface water runoff and water-phase loss of chlorpyrifos. In addition, predictions of flumetsulam (a weak acid) runoff and dynamics in soil were sensitive to the Freundlich equilibrium adsorption constant, soil pH and its dissociation coefficient.
Biobeds aim to create an environment whereby any pesticide spills are retained and then degraded, thus reducing the potential for surface or groundwater contamination. Biobeds may receive high concentrations of relatively complex mixtures of pesticides. The effects of concentration and pesticide interaction on degradation rate were therefore investigated. At concentrations up to 20 times the maximum recommended application rate for isoproturon and chlorothalonil, the rate of degradation in topsoil and biomix decreased with increasing concentration. With the exception of isoproturon at concentrations above 11 mg kg(-1), degradation was quicker in biomix (a composted mixture of topsoil, compost, and wheat straw) than in topsoil. One possible explanation for faster isoproturon degradation in topsoil as compared to biomix may be that previous treatments of isoproturon applied to the field soil as part of normal agricultural practices had resulted in proliferation of microbial communities specifically adapted to use isoproturon as an energy source. Such microbial adaptation could enhance the performance of a biobed. Studies with a mixture of isoproturon and chlorothalonil showed that interactions between pesticides are possible. In biomix, the degradation of either isoproturon or chlorothalonil was unaffected by the presence of the other pesticide, whereas in topsoil, isoproturon DT(50) values increased from 18.5 to 71.5 days in the presence of chlorothalonil. These studies suggest that biobeds appear capable of treating high concentrations of more than one pesticide.
The Minnesota Children's Pesticide Exposure Study (MNCPES) provides exposure, environmental, and biologic data relating to multipathway exposures of children for four primary pesticides (chlorpyrifos, malathion, diazinon, and atrazine), 14 secondary pesticides, and 13 polynuclear aromatic hydrocarbons (PAHs). Monitoring was performed on a probability-based sample of 102 children aged 3-12 in Minneapolis/St. Paul and in a nearby rural area (Goodhue and Rice counties). This paper provides estimated distributions of this population's exposures and exposure-related measurements and examines associations among the various measures via rank (Spearman) correlations. In addition, it provides some aggregate and cumulative exposure estimates for pesticides, and compares the relative intakes from inhalation and dietary ingestion. Intakes for the four primary pesticides appeared to come principally from the ingestion rather than the inhalation route; this was clearly true for chlorpyrifos but was less certain for the other three primary pesticides because of their higher degree of nondetects. Solid food rather than beverages was clearly the main contributor to the ingestion intake. Despite the dominance of the ingestion route, the urinary metabolite of chlorpyrifos exhibited a stronger association with the air measurements than with the dietary measures. Personal-air samples exhibited strong rank correlations with indoor air samples for chlorpyrifos, malathion, and diazinon (0.81, 0.51, and 0.62, respectively), while personal-air atrazine levels correlated well with outdoor levels (0.69); personal-air diazinon levels also correlated well with outdoor levels (0.67). For the PAHs, many significant associations were evident among the various air samples and for the air samples with the dust samples, especially for those compounds with consistently high percent measurable values (particularly fluoranthene, phenanthrene, and pyrene).
Although a number of health hazards associated with pesticide exposure have been well documented, relatively little is known about the knowledge and health beliefs that may influence pesticide handling. This study measured knowledge levels concerning pesticide safety and precautionary handling among applicators and examined relationships between knowledge scores and intentions to use handling precautions, perceptions of pesticide safety peer norms, and perceived self-efficacy to prevent personal exposure. Telephone interviews were conducted with a randomly selected sample of 164 dairy farmers who were pesticide applicators residing in Wisconsin (response rate = 77.4%). The percentage of correct responses to 18 knowledge items ranged from 100% to 45.7%. Knowledge levels were positively related to intentions, beliefs, and self-efficacy regarding use of personal protective gear but were not significantly related to risk perceptions and peer norms concerning pesticide safety.