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Primary, secondary, and tertiary prevention in reducing pesticide-related illness in farmers.

American farmers are a specific population with specific health concerns, and there is little in the literature that addresses nursing care of farmers. The farmer needs to be educated and assessed for the potential of poisoning injury related to pesticide exposure. Studies done by the National Cancer Institute (NCI) and others have shown a somewhat greater risk of specific cancers in farmers using pesticides. Acute exposures and chronic conditions resulting from years of exposure to pesticides are oftentimes not attributed to pesticides. By use of the nursing process, nurses can develop programs at all levels of prevention to deal with this problem. This article describes such programs, as well as providing resources useful in their development.

Agricultural Workers' Diseases↗

Biologically based pesticide dose estimates for children in an agricultural community.

Current pesticide health risk assessments in the United States require the characterization of aggregate exposure and cumulative risk in the setting of food tolerances. Biologic monitoring can aggregate exposures from all sources and routes, and can integrate exposures for chemicals with a common mechanism of action. Its value was demonstrated in a recent study of organophosphorus (OP) pesticide exposure among 109 children in an agricultural community in Washington State; 91 of the children had parents working in agriculture. We estimated individual OP pesticide doses from urinary metabolite concentrations with a deterministic steady state model, and compared them to toxicologic reference values. We evaluated doses by assuming that metabolites were attributable entirely to either azinphos-methyl or phosmet, the two OP pesticides used most frequently in the region. Creatinine-adjusted average dose estimates during the 6- to 8-week spraying season ranged from 0 to 36 microg/kg/day. For children whose parents worked in agriculture as either orchard applicators or as fieldworkers, 56% of the doses estimated for the spray season exceeded the U.S. Environmental Protection Agency (EPA) chronic dietary reference dose, and 19% exceeded the World Health Organization acceptable daily intake values for azinphos-methyl. The corresponding values for children whose parents did not work in agriculture were 44 and 22%, respectively. The percentage of children exceeding the relevant reference values for phosmet was substantially lower (< 10%). Single-day dose estimates ranged from 0 to 72 microg/kg/day, and 26% of these exceeded the EPA acute reference dose for azinphos-methyl. We also generated dose estimates by adjustment for total daily urine volume, and these estimates were consistently higher than the creatinine-adjusted estimates. None of the dose estimates exceeded the empirically derived no-observable-adverse-effect levels for these compounds. The study took place in an agricultural region during a period of active spraying, so the dose estimates for this population should not be considered representative of exposures in the general population. The findings indicate that children living in agricultural regions represent an important subpopulation for public health evaluation, and that their exposures fall within a range of regulatory concern. They also demonstrate that biologically based exposure measures can provide data for health risk evaluations in such populations.

Agriculture↗

Neuropsychologic effects of long-term exposure to pesticides: results from the French Phytoner study.

The Phytoner study investigated a possible association between neuropsychologic performances and long-term exposure to pesticides in Bordeaux vineyard workers, most of whom use fungicides. Among the 917 subjects interviewed from February 1997 to August 1998, 528 were directly exposed to pesticides through mixing and/or spraying (mean exposure duration: 22 years), 173 were indirectly exposed through contact with treated plants, and 216 were never exposed. All subjects performed neuropsychologic tests administered at home by trained psychologists. The risk of scoring a low performance on the tests was constantly higher in exposed subjects. When taking into account educational level, age, sex, alcohol consumption, smoking, environmental exposures, and depressive symptoms and when restricting analysis to subgroups, results remained significant for most tests, with odds ratios (OR) exceeding 2. These results point to long-term cognitive effects of low-level exposure to pesticides in occupational conditions. Given the frequency of pesticide use and the potential disabilities resulting from cognitive impairments, further toxicologic and epidemiologic research is needed to confirm these results and assess the impact on public health.

Agricultural Workers' Diseases↗

Predicting children's short-term exposure to pesticides: results of a questionnaire screening approach.

The ability of questionnaires to predict children's exposure to pesticides was examined as part of the Minnesota Children's Pesticide Exposure Study (MNCPES). The MNCPES focused on a probability sample of 102 children between the ages of 3 and 13 years living in either urban (Minneapolis and St. Paul, MN) or nonurban (Rice and Goodhue Counties in Minnesota) households. Samples were collected in a variety of relevant media (air, food, beverages, tap water, house dust, soil, urine), and chemical analyses emphasized three organophosphate insecticides (chlorpyrifos, diazinon, malathion) and a herbicide (atrazine). Results indicate that the residential pesticide-use questions and overall screening approach used in the MNCPES were ineffective for identifying and oversampling children/households with higher levels of individual target pesticides.

Adolescent↗

Measurement of pesticides and other toxicants in amniotic fluid as a potential biomarker of prenatal exposure: a validation study.

Prenatal pesticide exposures may adversely affect children's health. However, exposure and health research is hampered by the lack of reliable fetal exposure data. No studies have been published that report measurements of commonly used nonpersistent pesticides in human amniotic fluid, although recent studies of pesticides in urine from pregnant women and in meconium indicate that fetuses are exposed to these chemicals. Amniotic fluid collected during amniocentesis is the only medium available to characterize direct fetal exposures early in pregnancy (approximately 18 weeks of gestation). As a first step in validating this exposure biomarker, we collected 100 amniotic fluid samples slated for disposal and evaluated analytical methods to measure organophosphate and carbamate pesticides and metabolites, synthetic pyrethroid metabolites, herbicides, and chlorinated phenolic compounds. The following six phenols were detected (detection frequency): 1- and 2-naphthol (70%), 2,5-dichlorophenol (55%), carbofuranphenol (5%), ortho-phenylphenol (30%), and pentachlorophenol (15%), with geometric mean concentrations of 0.72, 0.39, 0.12, 0.13, and 0.23 microg/L, respectively, for positive values. The organophosphate metabolites diethylphosphate and dimethylphosphate were detected in two (10%) samples, and dimethylthiophosphate was detected in one (5%) sample, with geometric mean concentrations of 0.31, 0.32, and 0.43 microg/L, respectively, for positive values. These levels are low compared with levels reported in urine, blood, and meconium in other studies, but indicate direct exposures to the young fetus, possibly during critical periods of development. Results of this pilot study suggest that amniotic fluid offers a unique opportunity to investigate fetal exposures and health risks.

Adolescent↗

Lessons learned for the assessment of children's pesticide exposure: critical sampling and analytical issues for future studies.

In this article we examine sampling strategies and analytical methods used in a series of recent studies of children's exposure to pesticides that may prove useful in the design and implementation of the National Children's Study. We focus primarily on the experiences of four of the National Institute of Environmental Health Sciences/U.S. Environmental Protection Agency/ Children's Centers and include University of Washington studies that predated these centers. These studies have measured maternal exposures, perinatal exposures, infant and toddler exposures, and exposure among young children through biologic monitoring, personal sampling, and environmental monitoring. Biologic monitoring appears to be the best available method for assessment of children's exposure to pesticides, with some limitations. It is likely that a combination of biomarkers, environmental measurements, and questionnaires will be needed after careful consideration of the specific hypotheses posed by investigators and the limitations of each exposure metric. The value of environmental measurements, such as surface and toy wipes and indoor air or house dust samples, deserves further investigation. Emphasis on personal rather than environmental sampling in conjunction with urine or blood sampling is likely to be most effective at classifying exposure. For infants and young children, ease of urine collection (possible for extended periods of time) may make these samples the best available approach to capturing exposure variability of nonpersistent pesticides; additional validation studies are needed. Saliva measurements of pesticides, if feasible, would overcome the limitations of urinary metabolite-based exposure analysis. Global positioning system technology appears promising in the delineation of children's time-location patterns.

Child↗

Pesticide testing on human subjects: weighing benefits and risks.

In the debate surrounding testing pesticides on human subjects, two distinct positions have emerged. The first position holds that pesticide experiments on human subjects should be allowed, but only under stringent scientific and ethical standards. The second position asserts that these experiments should never be allowed. In this article, we evaluate what we consider to be the strongest argument for the second position--namely, that the benefits of the experiments are not significant enough to justify the risks posed to healthy subjects. We challenge this argument by examining the benefits and risks of testing pesticides on human subjects. We argue that a study that intentionally exposes humans subjects to pesticides should be permitted if a) the knowledge gained from the study is expected to promote human health; b) the knowledge cannot be reasonably obtained by other means; c) the study is not expected to cause serious or irreversible harm to the subjects; and d) appropriate safeguards are in place to minimize harm to the subjects.

Humans↗

Pesticide use in agriculture.

During the last three decades, the use of modern organic synthetic pesticides has increased about 40-fold. Total U.S. production, for domestic and expert use, in 1976 was about 1.4 million pounds. Crops receiving the most intensive application of various pesticides were cotton for insecticides, corn for herbicides, and fruits and vegetables for fungicides. Examination of use trends of pesticides indicates that the volume in pounds of herbicides used on crops is increasing, whereas the quantities of insecticides and fungicides remain stable. New chemical classes of compounds such as the synthetic pyrethroid insecticides are being introduced, but are not yet significant in terms of their share of the market. The increased usage of pesticides, together with knowledge of some of their adverse effects, has alerted the public to the need for regulation. To assist in the regulatory decision-making process, emphasis is being placed on benefit-cost analyses. Additional and improved biological inputs and methodologies are needed to provide accurate analyses.

Agriculture↗

Multiple end point procedure to evaluate risk from pesticides.

Because of the potential environmental impact of pesticides and the large population potentially exposed, the effects of chronic exposure to pesticides need to be determined. Mutagenicity studies have been used to identify specific agents as potential carcinogens or other human health hazards. However, short-term tests are only theoretically correlated to carcinogenesis because their end points can measure only the genotoxic potential of chemicals, i.e., their activities as initiating agents in multistep carcinogenesis. The objective of our research presented here is to provide a comprehensive examination of the mechanism of toxicity of a series of pesticides. These are substances for which toxicity, at both the genetic and metabolic level, has not been adequately described. Preliminary results on a broad series of compounds belonging to different biological classes (herbicide, insecticide, fungicide) seem to indicate that pesticides are toxic but are poor initiating agents, as shown by negative or weak positive results on different genetic end points (gene mutations, DNA effects, and chromosome aberrations in vitro and in vivo). Immunochemical and biochemical studies, however, seem to indicate the cocarcinogenic and promoting potential of these chemicals. As an example, the genotoxic and biochemical effects induced by Fenarimol (a fungicide) are discussed. The results reported stress the importance of identifying chemicals that act at different levels of the multistep carcinogenesis process to ascertain the risk associated with exposure.

Animals↗

Pesticides in household dust and soil: exposure pathways for children of agricultural families.

Child of agriculture families are likely to be exposed to agricultural chemicals, even if they are not involved in farm activities. This study was designed to determine whether such children are exposed to higher levels of pesticides than children whose parents are not involved in agriculture and whose homes are not close to farms. Household dust and soil samples were collected in children's play areas from 59 residences in eastern Washington State (26 farming, 22 farmworker, and 11 nonfarming families). The majority of the farm families lived within 200 feet of an operating apple or pear orchard, whereas all reference homes were located at least a quarter of a mile from an orchard. Four organophosphorous (OP) insecticides commonly used on tree fruit were targeted for analysis: azinphosmethyl, chlorpyrifos, parathion, and phosmet. Samples were extracted and analyzed by gas chromatography/mass selective detection. Pesticide concentrations in household dust were significantly higher than in soil for all groups. OP levels for farmer/farm-worker families ranged from nondetectable to 930 ng/g in soil (0.93 ppm) and from nondetectable to 17,000 ng/g in dust (17 ppm); all four OP compounds were found in 62% of household dust samples, and two-thirds of the farm homes contained at least one OP above 1000 ng/g. Residues were found less frequently in reference homes and all levels were below 1000 ng/g. Household dust concentrations for all four target compounds were significantly lower in reference homes when compared to farmer/farmworker homes (Mann Whitney, U test; p < 0.05). These results demonstrate that children of agricultural families have a higher potential for exposure to OP pesticides than children of nonfarm families in this region. Measurable residues of a toxicity, I compound registered exclusively for agricultural use, azcnphosmettyl were found in household dust samples from all study homes, suggesting that low level exposure to such chemicals occurs throughout the region. Children's total and cumulative exposure to this pesticide class from household dust, soil, and other sources warrants further investigation.

Adult↗

Developmental neurotoxicology of endocrine disruptors and pesticides: identification of information gaps and research needs.

There is increasing evidence that some environmental chemicals can interrupt neurodevelopmental processes during critical periods of development, resulting in effects on sensory, motor, and cognitive function. It is now generally accepted that developing organisms are differentially sensitive to chemical exposure because of toxicokinetic and/or toxicodynamic factors. Regulatory mechanisms have been implemented to protect humans from over- or inappropriate exposures to environmental chemicals. Current regulatory practices, however, may be insufficient because of the possibility that some environmental chemicals interfere with endocrine function at key periods of neurodevelopment. In addition, a recent National Research Council (NRC) report on pesticide contamination in the diets of infants and children concluded that current regulatory practices may not sufficiently protect infants and children from the risk of pesticide exposure. The NRC report indicates that regulatory agencies might underestimate the actual exposure of infants and children to pesticides and rely too heavily on data from adults in the risk assessment of pesticides. Consideration of endocrine-disrupting chemicals and the differential susceptibility of infants and children has led to identification of a number of information gaps and research needs that should be addressed in order to improve future risk assessments for these chemicals.

Adult↗

Pesticide knowledge and risk perception among adolescent Latino farmworkers.

A substantial proportion of the agricultural production in the U.S. is dependent on the labor of Latino farmworkers. While exact figures are not known, it is estimated that adolescents make up 7% of this valuable workforce. These young workers may be at increased risk for the toxic effects of environmental exposures encountered during their work. Furthermore, language barriers and health beliefs may influence the risk perceptions of this population. We conducted a cross-sectional survey of migrant adolescent farmworkers in 1998 to investigate their work practices, health beliefs, and pesticide knowledge. The large majority of the adolescents in our sample were from Mexico, and 36.3% spoke primarily indigenous languages. Many of the adolescents (64.7%) were traveling and working in the U.S. independent of their parents. Few of the adolescents reported having received pesticide training; however, 21.6% of the sample reported that their current work involved mixing and/or applying agricultural chemicals. The scores on the pesticide knowledge questionnaire were found to significantly predict self-reported use of protection for adolescent farmworkers. The results of this study point to a need for improved pesticide training in youth agricultural workers and specialized education efforts directed toward minorities who speak indigenous dialects. Special attention is merited toward adolescent farmworkers who report that their work includes mixing or applying agricultural chemicals. As the number of adolescent farmworkers increases in the U.S. and the characteristics of the migrant stream continue to change, culturally and developmentally appropriate instruments are needed to adequately assess the health beliefs and protective practices of this population.

Adolescent↗

Simultaneous determination of the pesticides carbaryl and thiabendazole in environmental samples by a three-dimensional derivative variable-angle and a synchronous room-temperature phosphorescence spectroscopy.

A three-dimensional derivative variable-angle synchronous scanning (DVASS) and a synchronous scanning (SS) heavy-atom room-temperature phosphorimetry (HAI-RTP) method are reported, for the first time, to identify and quantify the spectral overlapping phosphorescent pesticides thiabendazole (TBZ) and carbaryl (CBL). These pesticides are widely used in agriculture. The phosphorescence emission of the two compounds was obtained using sodium sulfite as the O2 scavenger and an external heavy atom salt. A careful selection of these experimental variables has been carried out. The increase of selectivity afforded by the DVASS and the SS methodology permitted the demonstration of its applicability to the simultaneous determination of phosphorescent signals of these two pesticides with overlapping spectral profiles. Limits of detection ranged between 1.4 ng/mL for TBZ and 1.7 ng/mL for CBL. The proposed method has been satisfactorily applied to the analysis of both pesticides in different types of water samples.

Carbaryl↗

Noninvasive method for the assessment of dermal uptake of pesticides using attenuated total reflectance infrared spectroscopy.

Dermal absorption of pesticides is a primary exposure route for agricultural workers, but is not well characterized. Current measurement techniques are either invasive, such as tape-stripping, or require extensive sample preparation or analysis time, such as urinary metabolite monitoring or wipe sampling followed by gas chromatography analysis. We present the application of a noninvasive, spectroscopic approach for the measurement of pesticide absorption into skin. Attenuated total reflectance infrared spectroscopy (ATR-IR) was used to monitor directly the absorption of two pesticides--captan and azinphos-methyl--in ten volunteers over 20 min under occlusive conditions. We found substantial variability in absorption across subjects. Our results were comparable to those measured by the more traditional method of wipe-sampling followed by extraction and gas chromatography analysis. Multivariate data analysis, in the form of multivariate curve resolution (MCR), is a novel addition to this type of experiment, yielding time-resolved information unachievable by standard methods. These data are potentially more informative than the monitoring of blood or urinary metabolites because they can be acquired in essentially real-time, allowing observations of pesticide absorption on a rapid timescale rather than over hours or days.

Adolescent↗

[The removability of pesticides during the production of dialysis water (2)].

In many cases it can be demonstrated that the amount of plant protectives and plant treatments (pesticides) in drinking-water exceeds the permitted levels of the drinking-water decree which will be effective on October 1st, 1989. These components are in parts toxicologically important. Therefore, an examination was made on how far pesticides are removed during the conventional purification of dialysis water, but especially during the reverse osmosis. Retention rates of a reverse osmosis plant for 14 different pesticides were discovered which were used in different concentrations and compositions. In part 2 of this contribution the results of the investigation are presented. The figures demonstrate that almost all of the examined components were retained with an effectiveness of 92-98%. The elimination efficiency did not depend on the basic concentration of the pesticides. After an initial phase of 50 h duration, the permeat concentration reached a constant value which did not alter even after more than 700 h.

Dialysis↗

Determination of organochlorine pesticide residues in the blood of healthy individuals.

Pesticide use is one of several factors that have permitted maintenance of our supply of food in spite of continuing increase of the population. However, the use of biologically active compounds poses potential problems of toxicity. If the compound is used at any stage of food production, residues or derivatives may persist in food and the entire population may be exposed to the trace amounts of the material. The human body burden associated with long-term exposure may or may not be associated with illness. Persistent environmental contaminants such as pesticide residues have long been suspected to be implicated in cancer etiology. Organochlorine chemicals are persistent, lipophilic compounds commonly present in the environment. Some of them demonstrated carcinogenic activity in laboratory animals. Controversy still exists concerning their carcinogenic potential in humans. To answer this question, clinical toxicology laboratories should propose validated methodologies able to identify and quantify pesticide residues in biological samples. An example of chromatographic method dedicated to organochlorine residues is presented here and illustrated by results obtained in a healthy population (104 men, 147 women). Only 17.9% of the samples were free from detectable amounts of pesticides and p,p'-DDE 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene was the most frequently detected residue (66.5%). Hexachlorobenzene was found at detectable level in 13.5% of the samples.

Adolescent↗

Impact of pesticides use on human health in Mexico: a review.

Pesticides having a high adverse effect on the health and environment of inhabitants of the Mexican Republic were studied to establish the main parameters to bear in mind for their use and application. The investigation showed that Mexico is the agricultural zone with the highest health damage to its population from pesticides. The valid regulation norms for the use and application of these agrochemicals were analyzed. Case histories recorded by the public health sector in Mexico were reviewed. In this way, a strong relation was found between the health problems and the pesticides applied. Finally, the study concludes that the various Mexican States appear as a risk zone because of contamination by pesticides that are permitted by the regulation norms and by others whose use is prohibited in other countries and in Mexico. This situation causes a serious effect on the health deterioration of people who are exposed to these agro-chemicals and, in some cases, leads to death.

Age Distribution↗

[Communication related to pesticides use in a rural area of the state of Rio de Janeiro, Brazil].

OBJECTIVE: To assess communications aspects related to pesticide use in a rural area of the Rio de Janeiro state, Brazil. METHODS: The study was carried out in the area of São Lourenço stream. It was based on methodological triangulation comprising: semi-structured interviews and observation of a local population sample (about 600 inhabitants); structured questionnaire to collect data on the local community; and records of lectures given by argonomic engineers, pesticides traders and other public service professionals. RESULTS AND DISCUSSION: This study pointed out to the historical misinformation on pesticides in rural areas; the emphasis on technical language in educational and training activities available which constitutes a barrier for rural workers knowledge acquisition and empowerment; and the industry/commerce's pressure to legitimate pesticide trading, reinforcing the existing communication process, resulting in unfavorable inclusion of the rural worker into a broader market economy.

Brazil↗