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PubMed2002

Critical windows of exposure to household pesticides and risk of childhood leukemia.

The potential etiologic role of household pesticide exposures was examined in the Northern California Childhood Leukemia Study. A total of 162 patients (0-14 years old) with newly diagnosed leukemia were rapidly ascertained during 1995-1999, and 162 matched control subjects were randomly selected from the birth registry. The use of professional pest control services at any time from 1 year before birth to 3 years after was associated with a significantly increased risk of childhood leukemia [odds ratio (OR) = 2.8; 95% confidence interval (CI), 1.4-5.7], and the exposure during year 2 was associated with the highest risk (OR = 3.6; 95% CI, 1.6-8.3). The ORs for exposure to insecticides during the 3 months before pregnancy, pregnancy, and years 1, 2, and 3 were 1.8 (95% CI, 1.1-3.1), 2.1 (95% CI, 1.3-3.5), 1.7 (95% CI, 1.0-2.9), 1.6 (95% CI, 1.0-2.7), and 1.2 (95% CI, 0.7-2.1), respectively. Insecticide exposures early in life appear to be more significant than later exposures, and the highest risk was observed for exposure during pregnancy. Additionally, more frequent exposure to insecticides was associated with a higher risk. In contrast to insecticides, the association between herbicides and leukemia was weak and nonsignificant. Pesticides were also grouped based on where they were applied. Exposure to indoor pesticides was associated with an increased risk, whereas no significant association was observed for exposure to outdoor pesticides. The findings suggest that exposure to household pesticides is associated with an elevated risk of childhood leukemia and further indicate the importance of the timing and location of exposure.

Adolescent↗
PubMed1996

Exposure to pesticides and cryptorchidism: geographical evidence of a possible association.

Synthetic hormone-disrupting chemicals may play a role in the increased frequency of cryptorchidism observed in some studies. We used a spatial ecological design to search for variations in orchidopexy rates in the province of Granada in Spain and to search for relationships between these differences and geographical variations in exposure to pesticides. Orchidopexy rates were estimated for the period from 1980 to 1991 in all municipalities and health care districts served by the University of Granada Hospital. A random sample of males of the same age (1-16 years) admitted for any reason during the same period was used to estimate inpatient control rates. Each municipality was assigned to one of four levels of pesticide use. We used Poisson homogeneity tests to detect significant differences in rates of orchidopexy between districts and between levels of pesticide use. Poisson and logistic regression models were also used to estimate the strength of association between orchidopexy and level of pesticide use. Orchidopexy rates tended to be higher in districts near the Mediterranean coast where intensive farming is widespread. The city of Granada, where the reference hospital is located, also had higher figures both for orchidopexy and inpatient control rates. Regression models showed that the strength of association between orchidopexy and level of pesticide use tended to increase with higher levels of use, with the exception of level 0 (mainly in the city of Granada). Our results are compatible with a hypothetical association between exposure to hormone-disruptive chemicals and the induction of cryptorchidism. Several methodological limitations in the design make it necessary to evaluate the results with caution.

Adolescent↗
PubMed1978

Comparative aspects of pesticide metabolism in plants and animals.

Pesticide chemicals are an important component of modern agriculture. Through their use, plants and animals are exposed to pesticides directly and indirectly from transport through soil, water, and other environmental components. Pesticide chemicals which are absorbed by plants and animals undergo extensive biotransformation. Lipophilic compounds are converted to polar metabolites through a variety of microsomal and extramicrosomal reactions in plants and animals. Generally, biotransformations are qualitatively similar in both systems. However, there are important quantitative rate differences in metabolism which often determine the balance between activation and deactivation of a pesticide. Furthermore, there are qualitative differences in conjugative mechanisms in plants and animals. Animals through an efficient excretory system eliminate transformation products via the urine and feces. Since efficient excretory systems are absent in plants, terminal degradation products are stored as conjugates and/or derivatives which may be incorporated into the plants themselves. Metabolic transformations of selected pesticides illustrating various types of reactions in plants and animals are discussed.

Animals↗
PubMed2006

Measuring potential dermal transfer of a pesticide to children in a child care center.

Currently, the major determinants of children's exposure to pesticides are not fully understood, and approaches for measuring and assessing dermal exposure in a residential setting have not been sufficiently evaluated. In one approach, dermal exposure is estimated using empirically derived transfer coefficients. To assess the feasibility of using this approach for assessing children's exposure to pesticides, we conducted a study was conducted in a child care center that had a preexisting contract with a pest control service for regular monthly pesticide applications. Children in the selected child care center were monitored using full-body cotton garments to measure dermal loading. Pesticide residues on classroom surfaces were measured in the areas where the children spent time. Measured surface-wipe loadings ranged from 0.47 to 120 ng/cm2, and total garment loadings ranged from 0.5 to 660 pg/cm2. The garment and surface loading measurements were used to calculate dermal-transfer coefficients for use in assessing children's residential exposure to pesticides. Dermal-transfer coefficients calculated using these data range from approximately 10 to 6,000 cm2/hr. The wide range in these values demonstrates the importance of developing standard surface-measurement protocols if this approach is to be used to assess dermal exposure in a residential environment. The upper-range values resulting from this study were found to be similar to the default value used by the U.S. Environmental Protection Agency to assess children's dermal exposures resulting from contact with indoor surfaces.

Administration, Cutaneous↗
PubMed1983

Selected pesticide residues or metabolites in blood and urine specimens from a general population survey.

The National Center for Health Statistics collaborated with the National Human Monitoring Program of the U.S. Environmental Protection Agency (EPA) in a four-year study to assess the exposure of the general population to selected pesticides through analysis of blood serum and urine specimens. Specimens were collected on a national probability half sample of persons 12-74 years of age from 64 locations across the United States comprising the sample areas in the Second Health and Nutrition Examination Survey (NHANES II) and analyzed for selected organochlorine, carbamate, chlorophenoxy and organophosphorus pesticides. Medical, nutritional and pesticide usage data are also available for each sample person. Preliminary results of the blood serum and urine analyses indicate that the general population is being exposed to some of these types of pesticides. Since 1970, EPA has conducted a national probability sampling of human adipose tissue. Specimens obtained on a survey design representative of the general population were analyzed for selected organochlorine pesticides and toxic chemicals. Findings from the 1978 survey also indicate exposure of the general population to some of these chemicals. Medical data collected from both surveys have yielded no overt correlations between health effects and residue levels. More intensive statistical analyses are underway to investigate the possible existence of more subtle relationships.

Adolescent↗
PubMed2006

Organic diets significantly lower children's dietary exposure to organophosphorus pesticides.

We used a novel study design to measure dietary organophosphorus pesticide exposure in a group of 23 elementary school-age children through urinary biomonitoring. We substituted most of children's conventional diets with organic food items for 5 consecutive days and collected two spot daily urine samples, first-morning and before-bedtime voids, throughout the 15-day study period. We found that the median urinary concentrations of the specific metabolites for malathion and chlorpyrifos decreased to the nondetect levels immediately after the introduction of organic diets and remained nondetectable until the conventional diets were reintroduced. The median concentrations for other organophosphorus pesticide metabolites were also lower in the organic diet consumption days; however, the detection of those metabolites was not frequent enough to show any statistical significance. In conclusion, we were able to demonstrate that an organic diet provides a dramatic and immediate protective effect against exposures to organophosphorus pesticides that are commonly used in agricultural production. We also concluded that these children were most likely exposed to these organophosphorus pesticides exclusively through their diet. To our knowledge, this is the first study to employ a longitudinal design with a dietary intervention to assess children's exposure to pesticides. It provides new and persuasive evidence of the effectiveness of this intervention.

Agriculture↗
PubMed2006

Environmental exposure assessment of pesticides in farmworker homes.

Farmworkers and their families are exposed to pesticides both at work and in their homes. Environmental exposure assessment provides a means to evaluate pesticides in the environment and human contact with these chemicals through identification of sources and routes of exposure. To date, a variety of methods have been used to assess pesticide exposure among farmworker families, mostly focusing on dust and handwipe samples. While many of the methods are similar, differences in the collection, chemical analysis, and statistical analysis, can limit the comparability of results from farmworker studies. This mini-monograph discusses the strategies used to assess pesticide exposures, presents limitations in the available data for farmworkers, and suggests research needs for future studies of pesticide exposure among farmworker families.

Agriculture↗
PubMed1997

Household pesticides and risk of pediatric brain tumors.

A follow-up to a population-based case-control study of pediatric brain tumors in Los Angeles County, California, involving mothers of 224 cases and 218 controls, investigated the risk of household pesticide use from pregnancy to diagnosis. Risk was significantly elevated for prenatal exposure to flea/tick pesticides -odds ratio (OR) = 1.7; 95% confidence interval (CI), 1.1-2.6-, particularly among subjects less than 5 years old at diagnosis (OR = 2.5; CI, 1. 2-5.5). Prenatal risk was highest for mothers who prepared, applied, or cleaned up flea/tick products themselves (OR = 2.2; CI, 1.1-4.2; for subjects <5 years of age, OR = 5.4; CI, 1.3-22.3). A significant trend of increased risk with increased exposure was observed for number of pets treated (p = 0.04). Multivariate analysis of types of flea/tick products indicated that sprays/foggers were the only products significantly related to risk (OR =10.8; CI, 1.3-89.1). Elevated risks were not observed for termite or lice treatments, pesticides for nuisance pests, or yard and garden insecticides, herbicides, fungicides, or snail killer. Certain precautions,if ignored, were associated with significant increased risk: evacuating the house after spraying or dusting for pests (OR = 1.6; CI, 1.0-2.6), delaying the harvest of food after pesticide treatment (OR = 3.6; CI, 1.0-13.7), and following instructions on pesticide labels (OR = 3. 7;CI, 1.5-9.6). These findings indicate that chemicals used in flea/tick products may increase risk of pediatric brain tumors and suggest that further research be done to pinpoint specific chemicals involved.

Adolescent↗
PubMed1998

An anthropological approach to the evaluation of preschool children exposed to pesticides in Mexico.

In this comparative study, we compensated for many of the known variables that influence children's growth and development by selecting two groups of 4-5-year-old Yaqui children who reside in the Yaqui Valley of northwestern Mexico. These children share similar genetic backgrounds, diets, water mineral contents, cultural patterns, and social behaviors. The major difference was their exposure to pesticides. Pesticides have been applied to the agricultural area of the valley since the late 1940s. In 1990, high levels of multiple pesticides were found in the cord blood of newborns and in breast milk. Building on anthropological methods for rapid rural appraisal of problems within the environment, a Rapid Assessment Tool for Preschool Children (RATPC) was developed to measure growth and development. The children of the agrarian region were compared to children living in the foothills, where pesticide use is avoided. The RATPC measured varied aspects of physical growth and abilities to perform, or function in, normal childhood activities. No differences were found in growth patterns. Functionally, the exposed children demonstrated decreases in stamina, gross and fine eye-hand coordination, 30-minute memory, and the ability to draw a person. The RATPC also pointed out areas in which more in-depth research on the toxicology of pesticides would be valuable.

Anthropology↗
PubMed1998

Mode of carcinogenic action of pesticides inducing thyroid follicular cell tumors in rodents.

Of 240 pesticides screened for carcinogenicity by the U.S. Environmental Protection Agency Office of Pesticide Programs, at least 24 (10%) produce thyroid follicular cell tumors in rodents. Thirteen of the thyroid carcinogens also induce liver tumors, mainly in mice, and 9 chemicals produce tumors at other sites. Some mutagenic data are available on all 24 pesticides producing thyroid tumors. Mutagenicity does not seem to be a major determinant in thyroid carcinogenicity, except for possibly acetochlor; evidence is less convincing for ethylene thiourea and etridiazole. Studies on thyroid-pituitary functioning, including indications of thyroid cell growth and/or changes in thyroxine, triiodothyronine, or thyroid-stimulating hormone levels, are available on 19 pesticides. No such antithyroid information is available for etridiazole, N-octyl bicycloheptene dicarboximide, terbutryn, triadimefon, and trifluralin. Of the studied chemicals, only bromacil lacks antithyroid activity under study conditions. Intrathyroidal and extrathyroidal sites of action are found: amitrole, ethylene thiourea, and mancozeb are thyroid peroxidase inhibitors; and acetochlor, clofentezine, fenbuconazole, fipronil, pendimethalin, pentachloronitrobenzene, prodiamine, pyrimethanil, and thiazopyr seem to enhance the hepatic metabolism and excretion of thyroid hormone. Thus, with 12 pesticides that mode of action judgments can be made, 11 disrupt thyroid-pituitary homeostasis only; no chemical is mutagenic only; and acetochlor may have both antithyroid and some mutagenic activity. More information is needed to identify other potential antithyroid modes of thyroid carcinogenic action.

Adenocarcinoma, Follicular↗
PubMed2005

Pesticide safety training and access to field sanitation among migrant farmworker mothers from Starr County, Texas.

Very little published research describes employer compliance with EPA-mandated Worker Protection Standard (WPS) pesticide safety training and the OSHA Field Sanitation Standard among farmworker women in general and mothers specifically. A goal of both standards is limiting farmworkers' exposure to potentially hazardous agricultural pesticides. Data from a NIOSH-supported cohort study ("Injury and Illness Surveillance in Migrant Farmworker Families") allowed for examining these issues. The cohort included 267 migrant farmworker families who usually reside along the Texas-Mexico border (Starr County, Texas). Data were collected in Starr County during in-home interviews. Of 102 mothers who participated in migrant farm work during summer 2001, 57 (55.9%) reported having ever received training/instruction in the safe use of pesticides, while 47 (46.1%) reported having received training within the previous five years, as required by WPS. Of trained mothers, 91.5% to 93.6% reported that their training covered key WPS areas: (1) entry into a recently treated field, (2) pesticide related injuries/illnesses, and (3) where to go and who to contact for emergency care following exposure. Regarding access to field sanitation, 67.5% to 84.2% of 77 mothers who worked outside Texas reported employer-provided decontamination supplies (e.g., soap, wash water, towels, and toilet facilities). However, a strikingly smaller proportion (12% to 28%) of 25 mothers who worked within Texas reported access to the same resources, suggesting discrepancies in compliance across the U.S. Due to the low level of employer compliance with both WPS and OSHA mandated standards, increased enforcement and an alternate delivery of pesticide training is recommended.

Accident Prevention↗
PubMed2006

High pesticide exposure events among farmers and spouses enrolled in the Agricultural Health Study.

We completed a nested case-control analysis of factors associated with reporting a high pesticide exposure event (HPEE) by pesticide applicators and spouses during the five years since enrollment in the Agricultural Health Study (AHS). Cases and controls were identified from the 16,415 private pesticide applicators and 14,045 spouses with completed five-year follow-up interviews as of October 2000. Among the applicators, 306 cases with at least one HPEE in the five years since enrollment and 612 controls, randomly selected from those without a reported HPEE, were identified for analysis. Among the spouses, 63 cases were identified and 126 controls were selected. Risk for a new HPEE was increased among applicators reporting at enrollment ever having an HPEE with an odds ratio (OR) of 3.8 (95% CI: 2.7, 5.3). Compared to applicators who applied pesticides fewer than 5 days per year, the ORs ranged from 1.4 (95% CI: 0.9, 2.2) for 6 to 10 days per year to 2.2 (95% CI: 1.4, 3.6) for more than 20 application days per year. The incidence of HPEE among Iowa applicators was much greater (8.8/1000 applicators) than among North Carolina applicators (2.0/1000). Spouses reported fewer HPEEs compared to applicators (2/1000 spouses). Overall, the observed risk factors for new HPEEs among applicators are similar to risk factors observed in previous cross-sectional analyses of HPEE history. Further, only 13% of applicators and 22% of spouses with symptoms resulting from HPEE sought medical care, suggesting that pesticide poisoning surveillance data may seriously underreport the frequency of such events.

Adolescent↗
PubMed1991

Health and environmental hazards of pesticides.

The increase in world population and in demand for food and economic crops has put a pesticide burden on man and the environment. Pesticide residues from vector control and agricultural uses contaminate the terrestrial and aquatic surroundings and contribute to the pollution problem of the environment. Various human toxicoses have resulted from pesticide use. The major pathogenic pesticides are chlorinated hydrocarbons and organophosphates. With careful and enlightened use, pesticide toxicity, to both man and the environment, could be significantly reduced.

Animals↗
PubMedDate not supplied

Residue analysis of organophosphorus and organochlorine pesticides in fatty matrices by gas chromatography coupled with electron-capture detection.

A multiresidue method for the simultaneous determination of 22 organochlorine (OCs) and organophosphorus (Ops) pesticides (including isomers and metabolites), representing a wide range of physicochemical properties, was developed in fatty matrices extracted from meat. Pesticides were extracted from samples with acetonitrile/n-hexane (v:v, 1:1). The analytical screening was performed by gas chromatography coupled with electron-capture detection (ECD). The identification of compounds was based on their retention time and on comparison of the primary and secondary ions. The optimized method was validated by determining accuracy (recovery percentages), precision (repeatability and reproducibility), and sensitivity (detection and quantitation limits) from analyses of samples fortified at 38 to 300 ng/g levels. Correlation coefficients for the 22 extracted pesticide standard curves (linear regression analysis, n = 3) ranged from 0.998 to 1.000. Recovery studies from 2 g samples fortified at 3 levels demonstrated that the GC-ECD method provides 64.4-96.0% recovery for all pesticides except 2,4'-DDE (44.6-50.4%), 4,4'-DDE (51.1-57.5%) and 2,4'-DDT (50.0-51.2%). Both repeatability and reproducibility relative standard deviation values were < 20% for all residues. Detection limits ranged from 0.31 to 1.27 ng/g and quantification limits were between 1.04 and 4.25 ng/g. The proposed analytical method may be used as a simple procedure in routine determinations of OCs and Ops in meat. It can also be applied to the determination of pesticide multi-residues in other animal products such as butter and milk.

Chromatography, Gas↗
PubMed2003

Pesticide residues in rivers of a Brazilian Rain Forest Reserve: assessing potential concern for effects on aquatic life and human health.

Pesticide residues in water, sediment, and fish samples from rivers of a Brazilian Rain Forest Reserve were measured in November 1998, March 1999, and January 2000. Concentrations of the individual pesticides were compared to ecotoxicological benchmarks based on acute toxicity tests, and to regulatory guidelines to determine the potential concern for effects on aquatic life and human health. Pesticides and metabolites were detected at all 7 sites surveyed. Residues of a total of 27 pesticides or metabolites were found in water and/or sediment samples and fish have accumulated some of the most persistent of these residues. Measured concentrations in water and sediment indicated concern for preservation of aquatic fauna. Several pesticides in water were above levels for drinking water recommended by Brazilian and/or European Union authorities, indicating also a concern for human health.

Animals↗
PubMed2000

[Assessment of the chronic risk for ingestion of pesticide residues in the Brazilian diet].

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

Brazil↗
PubMed2004

Stress and immune responses of nestling tree swallows (Tachycineta bicolor) and eastern bluebirds (Sialia sialis) exposed to nonpersistent pesticides and p,p'-dichlorodiphenyldichloroethylene in apple orchards of southern Ontario, Canada.

To determine the relative effects of pesticides in current use and persistent residues of p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), we examined endocrine and immune responses in tree swallow (Tachycineta bicolor) and eastern bluebird (Sialia sialis) chicks from pesticide-sprayed apple orchards and reference sites in southern Ontario, Canada, during 2000 to 2001. Nests were exposed to as many as seven individual pesticide applications and up to five mixtures of pesticides during the egg-incubation and chick-rearing stage. Eggs collected from sprayed orchards contained higher p,p'-DDE concentrations than eggs from reference sites. In 16-d-old tree swallows, no significant differences were found in body mass, basal corticosterone concentration, or the corticosterone stress response following a 10-min restraint of chicks sampled from sprayed orchards and reference sites. Challenge with adrenocorticotrophic hormone (ACTH), however, produced a higher level of corticosterone secretion in tree swallow chicks from sprayed orchards relative to chicks from reference sites. Multiple regression analysis revealed no correlation between corticosterone concentrations and exposure to pesticide sprays or p,p'-DDE in tree swallow chicks. In contrast, bluebird chicks from sprayed orchards were less responsive to challenge with ACTH and a significant negative association was found between the response to ACTH challenge and p,p'-DDE concentration in eggs. The phytohemagglutinin (PHA)-induced cutaneous basophil hypersensitivity response was similar between exposure groups in both tree swallow and bluebird nestlings. Examination of immune organs revealed that tree swallow chicks from sprayed orchards had significantly greater thymic lymphocyte density and cortical/ medullary ratios and significant splenic B-cell hyperplasia relative to reference chicks. Our results indicate that modulation in the hypothalamus-pituitary-adrenal axis in songbird chicks tested are most associated with high p,p'-DDE egg concentrations. An alteration in the endocrine or immune system may compromise songbird survival immediately after fledging or during migration.

Adrenocorticotropic Hormone↗
PubMed2004

Aging reduces the bioavailability of even a weakly sorbed pesticide (carbaryl) in soil.

We investigated bioavailability and biodegradation of carbaryl (1-naphthyl methylcarbamate) in a soil with a long history of pesticide contamination from a storage facility located at Mamoon Kanjan, Pakistan. Carbaryl is weakly sorbed and generally considered to be easily degradable in soil. Extraction studies revealed that 49% of the total carbaryl in soil (88.0 mg kg(-1)) was not water-extractable and also not bioavailable, as demonstrated by inoculation of the contaminated soil with a carbaryl-degrading, mixed bacterial culture. Inoculation of the contaminated soil with the carbaryl-degrading culture showed that the bacteria were capable of degrading only the available (i.e., water-extractable) fraction of the pesticide. When the soil was pulverized in a ball mill to enhance the release of residue, an additional 19% of the carbaryl became bioavailable. A significant proportion of residue (approximately 33%) remained unavailable. The long (>12 years) contact time between the pesticide and soil (i.e., aging), allowing possible sequestration into soil nanopores and the organic matter matrices, is suggested to have rendered the pesticide unavailable for microbial degradation. High concentration (88.0 mg kg(-1)) in soil facilitated its persistence and sequestration. Results from the present study demonstrate that even a weakly sorbed and easily degradable pesticide, carbaryl, is effectively sequestrated in soil with time, rendering it partly inaccessible to microorganisms and affecting the bioavailability of the compound.

Adsorption↗