Pesticide storage and use patterns in Minnesota households with children

Household pesticide exposure: an online survey and shelf research in the Metropolitan Region of Rio de Janeiro, Brazil

This study aimed to estimate household pesticide exposure in adult individuals in the Metropolitan Region of Rio de Janeiro, Brazil, and to verify the accessibility of these products in local and online businesses. The data were collected by an online questionnaire (1,015 responses) and a shelf survey in physical and online stores. Among the responses analyzed, 87.5% used pesticides in the previous year, most of which against mosquitoes (64.7%). The most common application method was aerosol spray (38.1%), and the most frequent places of use were bedrooms (29.7%) and living rooms (22.1%). About 30% of respondents reported invasion of pests, and the most common pests were ants (79.1%) and cockroaches (40.4%). Service area (71.6%) and kitchen (17.5%) were the most common storage locations. Approximately 91% of those who lived with children aged under 18 used pesticides. The use of chemical group of pyrethroids prevailed (81.6%), and 90.8% of the reportedly used products are class II [55.7% (highly toxic)] or class III [35.1% (medium toxic)]. The most significant amount of purchased products was in the pest category, followed by mosquitoes. More variety of products were available in online stores than in physical stores. The high exposure of the population to pesticides at household is a public health issue and confirms the need for studies that better assess the risks and consequences of chronic and low-dose exposure to these substances. It is essential to inform the population about the uncertainties and potential risks of indiscriminate use so that they can choose whether to use pesticides in their households.

Pesticides and pollinators: A socioecological synthesis

The relationship between pesticides and pollinators, while attracting no shortage of attention from scientists, regulators, and the public, has proven resistant to scientific synthesis and fractious in matters of policy and public opinion. This is in part because the issue has been approached in a compartmentalized and intradisciplinary way, such that evaluations of organismal pesticide effects remain largely disjoint from their upstream drivers and downstream consequences. Here, we present a socioecological framework designed to synthesize the pesticide-pollinator system and inform future scholarship and action. Our framework consists of three interlocking domains-pesticide use, pesticide exposure, and pesticide effects-each consisting of causally linked patterns, processes, and states. We elaborate each of these domains and their linkages, reviewing relevant literature and providing empirical case studies. We then propose guidelines for future pesticide-pollinator scholarship and action agenda aimed at strengthening knowledge in neglected domains and integrating knowledge across domains to provide decision support for stakeholders and policymakers. Specifically, we emphasize (1) stakeholder engagement, (2) mechanistic study of pesticide exposure, (3) understanding the propagation of pesticide effects across levels of organization, and (4) full-cost accounting of the externalities of pesticide use and regulation. Addressing these items will require transdisciplinary collaborations within and beyond the scientific community, including the expertise of farmers, agrochemical developers, and policymakers in an extended peer community.

An algorithm for quantitatively estimating non-occupational pesticide exposure intensity for spouses in the Agricultural Health Study

Residents of agricultural areas experience pesticide exposures from sources other than direct agricultural work. We developed a quantitative, active ingredient-specific algorithm for cumulative (adult, married lifetime) non-occupational pesticide exposure intensity for spouses of farmers who applied pesticides in the Agricultural Health Study (AHS). The algorithm addressed three exposure pathways: take-home, agricultural drift, and residential pesticide use. Pathway-specific equations combined (i) weights derived from previous meta-analyses of published pesticide exposure data and (ii) information from the questionnaire on frequency and duration of pesticide use by applicators, home proximity to treated fields, residential pesticide usage (e.g., termite treatments), and spouse's off-farm employment (proxy for time at home). The residential use equation also incorporated a published probability matrix that documented the likelihood active ingredients were used in home pest treatment products. We illustrate use of these equations by calculating exposure intensities for the insecticide chlorpyrifos and herbicide atrazine for 19,959 spouses. Non-zero estimates for ≥1 pathway were found for 78% and 77% of spouses for chlorpyrifos and atrazine, respectively. Variability in exposed spouses' intensity estimates was observed for both pesticides, with 75th to 25th percentile ratios ranging from 7.1 to 7.3 for take-home, 6.5 to 8.5 for drift, 2.4 to 2.8 for residential use, and 3.8 to 7.0 for the summed pathways. Take-home and drift estimates were highly correlated (≥0.98), but were not correlated with residential use (0.01‒0.02). This algorithm represents an important advancement in quantifying non-occupational pesticide relative exposure differences and will facilitate improved etiologic analyses in the AHS spouses. The algorithm could be adapted to studies with similar information.

Factors driving public tolerance levels and information-seeking behaviour concerning insects in the household environment

BACKGROUND

The public's negative attitudes towards household insects drive tolerance for these insects and their control. Tolerance levels are important in integrated pest management (IPM), as are pest knowledge and information. The risk information seeking and processing (RISP) model describes the relationships between personal factors and information-seeking behaviour. We combined IPM and RISP to determine important relationships between factors driving insect tolerance levels and information-seeking behaviour through an online survey and tested whether this model is valid and generally applicable.

RESULTS

Relationships between variables from both IPM and RISP models were tested for seven insect species. Tolerance levels were measured with two factors: willingness to pay for pest control and whether insects are tolerated. Willingness to pay for control was positively affected by age, experience, risk perception, insect characteristics, and negative emotions and affected behavioural intention, by influencing information sufficiency and information-seeking behaviour. Tolerability was influenced by perception of insect characteristics and determines whether control measures are taken.

CONCLUSION

It was possible to combine the RISP and IPM models. Relevant driving factors were a person's age, experience, risk perception, negative affective responses, tolerance levels, relevant channel beliefs about online forums, information sufficiency and information-seeking behaviour. There was, however, variation in important factors between different insects. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Use of the "Exposome" in the Practice of Epidemiology: A Primer on -Omic Technologies

The exposome has been defined as the totality of exposures individuals experience over the course of their lives and how those exposures affect health. Three domains of the exposome have been identified: internal, specific external, and general external. Internal factors are those that are unique to the individual, and specific external factors include occupational exposures and lifestyle factors. The general external domain includes sociodemographic factors such as educational level and financial status. Eliciting information on the exposome is daunting and not feasible at present; the undertaking may never be fully realized. A variety of tools have been identified to measure the exposome. Biomarker measurements will be one of the major tools in exposomic studies. However, exposure data can also be obtained from other sources such as sensors, geographic information systems, and conventional tools such as survey instruments. Proof-of-concept studies are being conducted that show the promise of exposomic investigation and the integration of different kinds of data. The inherent value of exposomic data in epidemiologic studies is that they can provide greater understanding of the relationships among a broad range of chemical and other risk factors and health conditions and ultimately lead to more effective and efficient disease prevention and control.

Residential Exposure to Pesticide During Childhood and Childhood Cancers: A Meta-Analysis

CONTEXT

There is an increasing concern about chronic low-level pesticide exposure during childhood and its influence on childhood cancers.

OBJECTIVE

In this meta-analysis, we aimed to examine associations between residential childhood pesticide exposures and childhood cancers.

DATA SOURCES

We searched all observational studies published in PubMed before February 2014 and reviewed reference sections of articles derived from searches.

STUDY SELECTION

The literature search yielded 277 studies that met inclusion criteria.

DATA EXTRACTION

Sixteen studies were included in the meta-analysis. We calculated effect sizes and 95% confidence intervals (CIs) by using a random effect model with inverse variance weights.

RESULTS

We found that childhood exposure to indoor but not outdoor residential insecticides was associated with a significant increase in risk of childhood leukemia (odds ratio [OR] = 1.47; 95% CI, 1.26-1.72; I(2) = 30%) and childhood lymphomas (OR = 1.43; 95% CI, 1.15-1.78; I(2) = 0%). A significant increase in risk of leukemia was also associated with herbicide exposure (OR = 1.26; 95% CI, 1.10-1.44; I(2) = 0%). Also observed was a positive but not statistically significant association between childhood home pesticide or herbicide exposure and childhood brain tumors.

LIMITATIONS

The small number of studies included in the analysis represents a major limitation of the current analysis.

CONCLUSIONS

Results from this meta-analysis indicated that children exposed to indoor insecticides would have a higher risk of childhood hematopoietic cancers. Additional research is needed to confirm the association between residential indoor pesticide exposures and childhood cancers. Meanwhile, preventive measures should be considered to reduce children's exposure to pesticides at home.

Insecticide exposure and farm history in relation to risk of lymphomas and leukemias in the Women's Health Initiative observational study cohort

PURPOSE

Relationships of farm history and insecticide exposure at home or work with lymphohematopoietic (LH) neoplasm risk were investigated in a large prospective cohort of US women.

METHODS

In questionnaires, women self-reported history living or working on a farm, personally mixing or applying insecticides, insecticide application in the home or workplace by a commercial service, and treating pets with insecticides. Relationships with non-Hodgkin lymphoma (NHL), chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, plasma cell neoplasms, and myeloid leukemia were investigated using Cox proportional hazard models. Age and farming history were explored as effect modifiers.

RESULTS

The analysis included 76,493 women and 822 NHL cases. Women who ever lived or worked on a farm had 1.12 times the risk of NHL (95% confidence interval [CI] = 0.95-1.32) compared to those who did not. Women who reported that a commercial service ever applied insecticides in their immediate surroundings had 65% higher risk of CLL/SLL (95% CI = 1.15-2.38). Women aged less than 65 years who ever applied insecticides had 87% higher risk of DLBCL (95% CI = 1.13-3.09).

CONCLUSIONS

Insecticide exposures may contribute to risk of CLL/SLL and DLBCL. Future studies should examine relationships of LH subtypes with specific types of household insecticides.

Household and occupational exposure to pesticides and risk of breast cancer

The association between breast cancer in women and the use of household or occupational pesticides was examined in a population-based case-control study. This study was conducted in Western Australia in 2009-2011 and included 1,789 controls and 1,205 cases. Information on household pesticide exposure was collected from questionnaires. For occupational pesticide exposure, job-specific modules (JSMs) were used. To evaluate potential recall bias, we stratified the analysis by belief about whether pesticides contribute to breast cancer. Unconditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Women's exposures to pesticides in households and workplaces were not related to increased risk of breast cancer (OR = 1.10; CI: 0.86-1.37) and (OR = 0.77; CI: 0.45-1.32), respectively. The prevalence of occupational exposure to pesticides among women in our study was low. In the stratified analyses, the odd ratios associated with household pesticide use were similar among participants who believed pesticides increased breast cancer risk and those who did not. The results of our study did not show associations between breast cancer and household or occupational exposure to pesticides.

Prenatal and postnatal insecticide use and infant neuropsychological development in a multicenter birth cohort study

There is little evidence about exposure to currently used insecticides during early life periods and adverse effects on child neuropsychological development. The aim of this study is to examine the association between residential insecticide use during pregnancy and infancy, and the development of children. Study subjects were participants in the INMA (Environment and Childhood) Project, a Spanish multicenter birth cohort study. Prenatal and postnatal use of indoor insecticides and other variables were obtained from personal interview during pregnancy and infancy. Mental and psychomotor development was assessed around 14months using the Bayley Scales of Infant Development. The associations were analyzed by linear regression models. 54% of women used indoor insecticides at home during pregnancy and 47% postnatally. 34% of women used insecticide sprays and 33% used plug-in devices during pregnancy. During infancy, the percentage of women who used insecticide sprays decreased (22%), but the use of plug-in devices was similar to the prenatal period (32%). The use of insecticide sprays during pregnancy was associated with a decrement in psychomotor development (β=-1.9; 95%CI: -3.4, -0.5) but postnatal use did not associate with mental and psychomotor development. The negative effect was enhanced according to some modifying factors, such as being female, higher levels of prenatal exposure to PCB and mercury and belonging to the lowest social class. We found certain evidence about the adverse effect of using insecticide sprays during pregnancy on the psychomotor development of children. Some socio-demographic factors and other exposures could enhance that effect.

Temporal variation of residential pesticide use and comparison of two survey platforms: a longitudinal study among households with young children in Northern California

BACKGROUND

Pesticide use patterns are essential inputs into human pesticide exposure models. Currently, data included for modeling purposes have mostly been collected in cross-sectional surveys. However, it is questionable whether responses to one-time surveys are representative of pesticide use over longer periods, which is needed for assessment of health impact. This study was designed to evaluate population-wide temporal variations and within-household variations in reported residential pesticide use patterns and to compare alternative pesticide data collection methods - web surveys versus telephone interviews.

METHOD

A total of 481 households in Northern California provided up to 3 annual telephone interviews on residential pesticide use; 182 of these households provided up to 6 quarterly web surveys that covered the same topics for some of the same time periods. Information on frequency and areas of application were collected for outdoor and indoor sprays, indoor foggers, professional applications, and behind-the-neck treatments for pets. Population-wide temporal variation and within-household consistency were examined both within telephone surveys and within web surveys, and quantified using Generalized Estimating Equations and Mixed Effect Modeling. Reporting between the two methods, the telephone survey and the web survey, was also compared.

RESULTS

Use prevalence of outdoor sprays across the population reported in both the annual telephone surveys and the quarterly web surveys decreased over time, as did behind-the-neck treatment of pets reported in the quarterly web survey. Similarly, frequencies of use of these products decreased in the quarterly web surveys. Indoor sprays showed no statistically significant population-wide temporal variation in either survey. Intraclass correlation coefficients indicated consistent use within a household for behind-the-neck treatment on pets and outdoor sprays but great variability for the use of indoor sprays. Indoor sprays were most consistently applied in the bathroom and kitchen. Outdoor sprays were consistently more often applied by male household members, while indoor sprays were not. The two survey approaches obtained fairly similar results on the prevalence of using pesticides, but found discrepancies in use frequencies. In addition, the number of products purchased was positively correlated with application frequency for outdoor sprays (R = 0.51, p = 0.0005) but not for indoor sprays.

CONCLUSIONS

In this population, repeated surveys are necessary either to obtain a reliable estimate of the average household use of pesticides or to project potential temporal changes of pesticide use. Web surveys could collect comparable data to traditional telephone surveys for some information. However, researchers need to consider the internet acceptability among the target population and balance lower participant burden against the need for sufficiently accurate time-varying measurement, to improve subject retention in longitudinal surveys.

Modeling exposures to organophosphates and pyrethroids for children living in an urban low-income environment

Pesticide exposure in urban low-income residential environments may be elevated as a result of persistent application due to severe pest infestation. Children living in this environment may be a sensitive subpopulation for these non-dietary exposures, due to their physiological and behavioral differences. In this study, we provide an exposure modeling framework to simulate exposures for children in this environment and assess dominant exposure routes and sources of exposure variability, in order to characterize factors that influence risk. We use a dataset of pesticide measurements collected in 42 low-income dwellings, including vacuum dust and floor wipe samples from kitchens and living rooms. We fit distributions to the concentration measurements for the organophosphates measured, chlorpyrifos and diazinon, and the most prevalent pyrethroids (permethrin, cypermethrin, and cyfluthrin), and simulated 1000 homes from the distributions. Concentration measurements were then connected with activity pattern data, short-term dermal and ingestion exposures and absorbed doses were simulated for children ages 1-5 years. For both pesticide groups, exposure values ranged widely, with concentration values contributing most significantly to exposure variability, although approximately 20-fold variability was attributable to exposure factors alone. In addition, upper percentile exposed children usually had both higher concentrations as well as greater influences from exposure and dose factors. Differences were also seen across pesticide groups in dominant exposure pathways. Our analyses indicate a profile of factors that describe individuals likely to receive high doses of one or multiple pesticides and could allow for more targeted intervention strategies. More generally, this work provides a standard framework to evaluate and describe exposures to prevalent residential pesticides via multiple pathways.

Prenatal and postnatal residential usage of insecticides in a multicenter birth cohort in Spain

This study aimed to describe the residential use of insecticides in a birth cohort in Spain. Study subjects were 2,456 women enrolled into the INMA (Environment and Childhood) birth cohort followed prospectively during pregnancy and in the early postnatal period. The women were recruited at the beginning of their pregnancy between 2003 and 2008 in four regions of Spain. Socio-demographic, environmental and lifestyle information was obtained at two interviews during pregnancy, one at the first (mean:13.8±2.6 weeks of gestation) and the other at the third trimester (mean: 33.3±2.3 weeks of gestation). Information about prenatal use of indoor and outdoor insecticides (type, timing, place of application, place of storage) was obtained from the second interview. In a 3rd interview (mean: 16.2±6.9 months of age of children), information about postnatal indoor and outdoor insecticide use was obtained. Regression models examined the association between demographic and lifestyle factors and pesticide use to determine which characteristics predicted use prenatally and postnatally. Fifty-four percent of women reported using indoor insecticides during pregnancy, 45% in their bedroom and 47% elsewhere in the house. Plug-in devices were the most frequent application methods used in the pregnant woman's bedroom and insecticide sprays elsewhere in the house. The maternal factors related to prenatal use of indoor insecticides were parity, country of birth, educational level, region of residence, having a garden or yard with plants, and living near an agricultural area. These products continued to be used postnatally, although 20% of the women stopped using them. Foetuses and children are especially vulnerable to pesticide exposure; thus knowing how pesticides are used during pregnancy and infancy may be a starting point for the study of their potential effects on health as well as useful for designing preventive actions.

Characterization of residential pesticide use and chemical formulations through self-report and household inventory: the Northern California Childhood Leukemia study

BACKGROUND

Home and garden pesticide use has been linked to cancer and other health outcomes in numerous epidemiological studies. Exposure has generally been self-reported, so the assessment is potentially limited by recall bias and lack of information on specific chemicals.

OBJECTIVES

As part of an integrated assessment of residential pesticide exposure, we identified active ingredients and described patterns of storage and use.

METHODS

During a home interview of 500 residentially stable households enrolled in the Northern California Childhood Leukemia Study during 2001-2006, trained interviewers inventoried residential pesticide products and queried participants about their storage and use. U.S. Environmental Protection Agency registration numbers, recorded from pesticide product labels, and pesticide chemical codes were matched to public databases to obtain information on active ingredients and chemical class. Poisson regression was used to identify independent predictors of pesticide storage. Analyses were restricted to 259 participating control households.

RESULTS

Ninety-five percent (246 of 259) of the control households stored at least one pesticide product (median, 4). Indicators of higher sociodemographic status predicted more products in storage. We identified the most common characteristics: storage areas (garage, 40%; kitchen, 20%), pests treated (ants, 33%; weeds, 20%), pesticide types (insecticides, 46%; herbicides, 24%), chemical classes (pyrethroids, 77%; botanicals, 50%), active ingredients (pyrethrins, 43%) and synergists (piperonyl butoxide, 42%). Products could contain multiple active ingredients.

CONCLUSIONS

Our data on specific active ingredients and patterns of storage and use will inform future etiologic analyses of residential pesticide exposures from self-reported data, particularly among households with young children.

Human exposures to pesticides in the United States

Pesticides are used in most homes, businesses, and farms to control a variety of pests, including insects, weeds, fungi, rodents, and even microbial organisms. Inappropriate use of pesticides can lead to adverse effects to humans and the environment. This study provides updated information on the magnitude of adverse pesticide exposures in the United States. Data on pesticide exposure were obtained from calls to poison control centers (PCCs) reported by the American Association of Poison Control Centers. Estimates of emergency department visits, hospitalizations, and health care costs were reported by the Agency for Healthcare Research and Quality (AHRQ), and deaths from pesticide poisonings reported by the Centers for Disease Control and Prevention (CDC) WONDER (Wide-ranging Online Data for Epidemiologic Research). An average of 23 deaths occur each year with pesticides as the underlying cause of death, most due to suicidal ingestions. An average of 130,136 calls to poison control centers were reported from 2006 to 2010, with an average of 20,116 cases (17.8%) treated in health care facilities annually. AHQR reported an annual average of 7385 emergency room visits during 2006 to 2008, and 1419 annual hospitalizations during 2005 to 2009. Excluding cost from lost work time, hospital physician fees, and pesticide-induced cancers, the annual national cost associated with pesticide exposures was estimated as nearly $200 million USD based on data from emergency department visits, hospitalizations, and for deaths. Pesticide exposures remain a significant public health issue. Health care providers, cooperative extension agents, and pesticide manufactures can help prevent exposures by increasing education of parents and workers, encourage use of less toxic agents, and encourage the practice of integrated pest management.

The relation between dietary habits and urinary levels of 3-phenoxybenzoic acid, a pyrethroid metabolite

Concerns about pesticide exposure through food consumption have increased during the past several years. Pyrethroids are applied as insecticides throughout the world. Human metabolism of pyrethroids results in urinary metabolites that are suitable for biological monitoring. The objective of our study was to investigate the relation between food consumption and urinary levels of 3-phenoxybenzoic acid (3-PBA), a general metabolite of pyrethroids, in a non-occupational exposed adult population from the IDI-IRCCS, Rome, Italy. Information on socio-demographic characteristics, smoking, diet and self-reported household pesticide exposure was collected. Urinary 3-PBA level of each subject was measured and adjusted by urinary creatinine. We found that people consuming both raw and cooked vegetables five times weekly or more had higher mean levels of 3-PBA in urine (1.03 μg/g creatinine versus 0.52 μg/g creatinine; p=0.009 and 0.99 μg/g creatinine versus 0.58 μg/g creatinine; p=0.01, respectively) than subjects consuming less than five times weekly. In a multivariate model, after adjusting for age, sex, BMI, smoking and household insecticide exposure, high intake of raw vegetables (OR: 5.31; 95%CI: 1.32-21.3) and high intake of cooked vegetables, in particular cruciferous (OR: 4.67; 95%CI: 1.07-20.5) and leafy vegetables (OR: 6.88; 95%CI: 1.50-31.7), were associated with high urine 3-PBA levels (≥0.70 μg/g creatinine). The results of this study suggest that part of the variation in pyrethrois intake is explained by vegetable intake.

Indoor pesticide application practices and levels in homes of Bangkok Metropolitan Region

This study investigated the indoor application practices of pesticides in different homes located in urban, suburban, and rural areas of the Bangkok Metropolitan Region (BMR). A multi-stage stratified-judgmental sampling was applied to select 280 representative households in BMR for an in-depth questionnaire survey. We found about 71% of these households having mosquitoes as their main indoor nuisance. An inventory on the types and active ingredients was obtained through a shop-shelf survey. Among 22 available commercial products, 12 different active ingredients were observed with the pyrethroid containing pesticides are the most common. The stepwise regression analysis was conducted to reveal the statistical association between indoor levels of total pyrethriods (in the air and on the floor surface of homes) and the household application practices such as the overlap time period since the last application, application and storage locations, and frequency of applications, for instances.

Residential insecticide usage in northern California homes with young children

Residential insecticide usage and actual application details were collected in a population-based sample of 477 households residing within 22 counties in northern California with at least one child of age ≤ 5 years between January 2006 and August 2008. Structured telephone interviews were conducted collecting information on residential use of insecticides, including outdoor sprays, indoor sprays, indoor foggers, applications by professionals, and pet flea/tick control during the previous year. Interviews also covered post-treatment behaviors, which influence post-application exposure levels. Altogether, 80% of the households applied some type of insecticide in the previous year, with half of this population using two or more application methods. Of the households using insecticides, half reported applying insecticides relatively infrequently (<4 times per year), whereas 11-13% reported high frequency of use (>24 times per year). Application frequency was temperature dependent, with significantly more applications during the warmer months from May through October. Spot treatments appeared to be the most prevalent application pattern for sprays. For one out of three of the indoor applications, children played in the treated rooms on the day of the application, and for 40% of the outdoor applications, pets played in the treated area on the day of the application. These findings describing the intensity of insecticide use and accompanying behaviors in families with young children may inform future insecticide exposure modeling efforts, and ultimately, risk assessments.

Characterization of residential pest control products used in inner city communities in New York City

The Columbia Center for Children's Environmental Health (CCCEH) previously reported widespread residential insecticide use in urban communities in New York City. Research suggests that pyrethroids are replacing organophosphates (OPs) in response to 2000-2001 US EPA pesticide regulations restricting OP use. A systematic assessment of active ingredients used for residential pest control is lacking. We queried a database of pesticide applications reported by licensed applicators between 1999 and 2005 and surveyed pest control products available in 145 stores within 29 zip codes in the CCCEH catchment area including Northern Manhattan and the South Bronx. Pyrethroids, pyrethrins, piperonyl butoxide, and hydramethylnon were the most common insecticide active ingredients reported as used by licensed pesticide applicators within the 29 zip codes of the CCCEH catchment area between 1999 and 2005. Use of certain pyrethroids and some non-spray insecticides such as fipronil and boric acid increased significantly by year (logistic regression, OR>1.0, P<0.05), whereas use of OPs, including chlorpyrifos and diazinon decreased significantly by year (logistic regression, OR<1.0, P<0.05). Among pesticide applicators, the most commonly applied active ingredients were formulated as spray applications. With 145 stores in the catchment area, 120 (82.5%) carried at least one insecticide. Spray cans were most common (114/120 stores, 95%); gels were least common (31/120 stores, 25.8%). Among spray formulations, pyrethroid insecticides were the most common pesticide class and permethrin, a pyrethroid, was the most common individual active ingredient. In 2007, one store carried a product containing chlorpyrifos and one store carried a product containing diazinon. This survey suggests that certain pyrethroids and non-spray insecticides replaced OPs for pest control in this area. Chlorpyrifos and diazinon have nearly been eliminated from products marketed for residential pest control.

Impact of prenatal exposure to piperonyl butoxide and permethrin on 36-month neurodevelopment

OBJECTIVE

Recent pesticide-monitoring results suggest that a shift in residential pesticide exposure from organophosphorus insecticides to pyrethroid insecticides has occurred. Pyrethroid insecticides are potential neurodevelopmental toxicants and have not been evaluated for developmental toxicity. Our objective was to explore the association between prenatal exposure to permethrin (a common pyrethroid) and piperonyl butoxide (a pyrethroid synergist) and 36-month neurodevelopment.

METHODS

Participants is this study were part of a prospective cohort of black and Dominican mothers and newborns living in low-income neighborhoods in New York City. We examined 36-month cognitive and motor development (using the Bayley Scales of Infant Development, second edition) as a function of permethrin levels measured in maternal and umbilical cord plasma collected on delivery and permethrin and piperonyl butoxide levels measured in personal air collected during pregnancy. All models were controlled for gender, gestational age, ethnicity, maternal education, maternal intelligence, quality of the home environment, and prenatal exposure to environmental tobacco smoke and chlorpyrifos.

RESULTS

Prenatal exposure to permethrin in personal air and/or plasma was not associated with performance scores for the Bayley Mental Developmental Index or the Psychomotor Developmental Index. After data adjustment, children more highly exposed to piperonyl butoxide in personal air samples (>4.34 ng/m(3)) scored 3.9 points lower on the Mental Developmental Index than those with lower exposures (95% confidence interval: -0.25 to -7.49).

CONCLUSIONS

Prenatal exposure to piperonyl butoxide was negatively associated with 36-month neurodevelopment.

Lupus erythematosus. Are residential insecticides exposure the missing link?

Although the etiology of systemic lupus erythematosus (SLE) remains to be fully elucidated, it is now apparent that multiple genetic and environmental factors are at play. Because lupus has a strong female preponderance, several studies have examined the role of female hormones in disease etiology. Yet this knowledge has not helped to explain lupus etiology or to prevent it. Estrogens exist not only as natural or drug compounds, but also as environmental chemical contaminant and women are highly exposed to all of them. Estrogenic activity has been found in a number of pesticides including pyrethroids that are largely used in the household. Although there is only a small amount of published data examining a possible causal relationship between lupus and pesticides it can be hypothesized that pesticides, in particular insecticides, through their estrogenic activity and capacity to induce oxidative stress provoke autoimmune reaction influencing lupus development.

Selection bias in case-control studies on household exposure to pesticides and childhood acute leukemia

The goal of this study was to investigate the potential for selection bias in published case-control studies on household exposure to pesticides and childhood acute leukemia; most studies have reported positive findings. Items to evaluate the potential for selection bias were first developed. They focused on the source populations that gave rise to cases and controls, the probabilistic selection of subjects from the source, and the losses of the subjects actually selected. A quantitative assessment of bias was also carried out. Potential sources of selection bias were found in all the studies, but none of them were observed across all the studies. Main sources of potential bias were a non-concurrent selection of controls with respect to cases, the use of control diagnoses possibly caused by pesticide exposure in hospital-based studies, and non-participation of selected eligible subjects. A quantitative assessment of bias concluded that non-participation alone could not explain the reported positive associations. We conclude that overall, selection bias, as a likely source of bias in these studies, does not seem to explain their positive findings. Our analysis provides arguments strengthening the conclusions on associations reported in earlier studies.

Season of birth and risk for adult onset glioma

Adult onset glioma is a rare cancer which occurs more frequently in Caucasians than African Americans, and in men than women. The etiology of this disease is largely unknown. Exposure to ionizing radiation is the only well established environmental risk factor, and this factor explains only a small percentage of cases. Several recent studies have reported an association between season of birth and glioma risk. This paper reviews the plausibility of evidence focusing on the seasonal interrelation of farming, allergies, viruses, vitamin D, diet, birth weight, and handedness. To date, a convincing explanation for the occurrence of adult gliomas decades after a seasonal exposure at birth remains elusive.

A biomarker validation study of prenatal chlorpyrifos exposure within an inner-city cohort during pregnancy

BACKGROUND

We previously documented significant decreases in chlorpyrifos concentrations in maternal personal and indoor air samples among pregnant African-American and Dominican women from New York City after the 2000-2001 restrictions on its residential use.

OBJECTIVE

We undertook a biomarker validation study within the same cohort to evaluate trends over time in multiple biomarkers of prenatal chlorpyrifos exposure.

METHODS

Subjects were enrolled between February 2001 and May 2004 (n = 102). We measured 3,5,6-trichloro-2-pyridinol (TCPy) in postpartum meconium (n = 83), repeat prenatal maternal spot urine samples (n = 253), and postnatal urine from the mothers (n = 73) and newborns (n = 59). We measured chlorpyrifos in postnatal maternal (n = 92) and umbilical cord (n = 65) blood.

RESULTS

We did not detect TCPy in infant urine, but all other biomarkers showed a highly significant decrease in detection frequencies (chi2 = 7.8-34.0, p < or = 0.005) and mean ranks (p < or = 0.006, Kruskal-Wallis) among subjects enrolled in 2003-2004 compared with those enrolled in 2001-2002. Chlorpyrifos in maternal personal and indoor air declined 2- to 3-fold over the same period (p < 0.05). In 2001-2002 samples, TCPy levels in repeat prenatal urine were positively correlated (r = 0.23-0.56), but within-subject variability exceeded between-subject variability (intraclass correlation coefficient = 0.43); indoor air levels explained 19% of the variance in prenatal urine TCPy (p = 0.001). Meconium TCPy concentrations were positively correlated with chlorpyrifos in maternal and cord blood (r = 0.25-0.33, p < 0.05) and with TCPy in maternal urine (r = 0.31, p < 0.01).

CONCLUSIONS

Results suggest the biomarkers are reliable dosimeters to differentiate between groups with prenatal chlorpyrifos exposures varying by a factor of 2 or more and vividly illustrate the efficacy of residential restriction on chlorpyrifos to reduce the internal dose during pregnancy.

Risk of childhood cancers associated with residence in agriculturally intense areas in the United States

BACKGROUND

The potential for widespread exposure to agricultural pesticides through drift during application raises concerns about possible health effects to exposed children living in areas of high agricultural activity.

OBJECTIVES

We evaluated whether residence in a county with greater agricultural activity was associated with risk of developing cancer in children < 15 years of age.

METHODS

Incidence data for U.S. children 0-14 years of age diagnosed with cancer between 1995 and 2001 were provided by member registries of the North American Association of Central Cancer Registries. We determined percent cropland for each county using agricultural census data, and used the overall study distribution to classify agriculturally intense counties. We estimated odds ratios and 95% confidence intervals for all ages and 5-year age groups for total cancers and selected cancer sites using logistic regression.

RESULTS

Our study results showed statistically significant increased risk estimates for many types of childhood cancers associated with residence at diagnosis in counties having a moderate to high level of agricultural activity, with a remarkably consistent dose-response effect seen for counties having >or= 60% of the total county acreage devoted to farming. Risk for different cancers varied by type of crop.

CONCLUSIONS

Although interpretation is limited by the ecologic design, in this study we were able to evaluate rarer childhood cancers across a diverse agricultural topography. The findings of this exploratory study support a continued interest in the possible impact of long-term, low-level pesticide exposure in communities located in agriculturally intense areas.

Pesticide loadings of select organophosphate and pyrethroid pesticides in urban public housing

We investigated the magnitude and distribution of pyrethroid and organophosphate pesticide loadings within public housing dwellings in Boston, Massachusetts and compared the results using various sampling methods. We collected dust matrices from living room and kitchen in 42 apartments and analyzed for eleven pyrethoids (e.g., permethrin and cyfluthrin) and two organophosphates (chlorpyrifos and diazinon) in house dust using GC/MS. Agreement between sampling methods were evaluated using Spearman correlations and Kappa statistics. Permethrin and chlorpyrifos were detected in kitchen floor wipes in all homes, followed in frequency of detects by diazinon (98%), cypermethrin (90%) and cyfluthrin (71%). At least six pesticides were detected in kitchen floor wipes in the majority of the homes (range 3-8). Positive and statistically significant correlations among dust matrices were observed between kitchen floor wipes and living room vacuum dust, including for diazinon (r=0.62) and cyfluthrin (r=0.69). Detection of several pesticides including banned or restricted use products in some public housing units, underscore the need for alternative pest management strategies that embrace the safe and judicious use of pest control products.

Household exposure to pesticides and risk of childhood hematopoietic malignancies: The ESCALE study (SFCE)

OBJECTIVES

We investigated the role of household exposure to pesticides in the etiology of childhood hematopoietic malignancies.

METHODS

The national registry-based case-control study ESCALE (Etude sur les cancers de l'enfant) was carried out in France over the period 2003-2004. Population controls were frequency matched with the cases on age and sex. Maternal household use of pesticides during pregnancy and paternal use during pregnancy or childhood were reported by the mothers in a structured telephone questionnaire. Insecticides (used at home, on pets, or for garden crops), herbicides, and fungicides were distinguished. We estimated odds ratios (ORs) using unconditional regression models closely adjusting for age, sex, degree of urbanization, and type of housing (flat or house).

RESULTS

We included a total of 764 cases of acute leukemia (AL), 130 of Hodgkin lymphoma (HL), 166 of non-Hodgkin lymphoma (NHL), and 1,681 controls. Insecticide use during pregnancy was significantly associated with childhood AL [OR = 2.1; 95% confidence interval (CI), 1.7-2.5], both lymphoblastic and myeloblastic, NHL (OR = 1.8; 95% CI, 1.3-2.6), mainly for Burkitt lymphoma (OR = 2.7; 95% CI, 1.6-4.5), and mixed-cell HL (OR = 4.1; 95% CI, 1.4-11.8), but not nodular sclerosis HL (OR = 1.1; 95% CI, 0.6-1.9). Paternal household use of pesticides was also related to AL (OR = 1.5; 95% CI, 1.2-1.8) and NHL (OR = 1.7; 95% CI, 1.2-2.6); but for AL the relationships did not remain after adjustment for maternal pesticide use during pregnancy.

CONCLUSION

The study findings strengthen the hypothesis that domestic use of pesticides may play a role in the etiology of childhood hematopoietic malignancies. The consistency of the findings with those of previous studies on AL raises the question of the advisability of preventing pesticide use by pregnant women.

The association between residential pesticide use and cutaneous melanoma

Occupational pesticide exposure has been linked to cutaneous melanoma in epidemiological studies. We studied the association between cutaneous melanoma and the residential use of pesticides. This is a case-control study of cutaneous melanoma (287 incident cases; 299 controls). Data on pesticide use was obtained with a standardised interview. An increased risk of melanoma was found for high use (4 times annually) of indoor pesticides (odds ratio (OR)=2.18; 95% confidence intervals (CI) 1.07-4.43) compared to low use (1 times annually), after adjustment for sex, age, education, sun exposure and pigmentary characteristics. Subjects exposed for 10 years or more had two and a half times the risk (OR=2.46; 95% CI 1.23-4.94) of those exposed for less than 10 years. A dose response was observed for the intensity of pesticides use (p(trend)=0.027). The results indicate that residential pesticide exposure may be an independent risk factor for cutaneous melanoma.

Differential sensitivity to anticholinesterase insecticides in the juvenile rat: effects on thermoregulation

Organophosphate (OP) and carbamate (CB) insecticides inhibit cholinesterase (ChE) activity and induce acute hypothermia in adult rats. Studies showed that juveniles are generally more susceptible to neurotoxic insult than adults. However, little is known concerning the effects of OP and CB pesticides on thermoregulation in developing animals. Thus, alterations in core body temperature (Tc) in juvenile animals exposed to an OP and CB insecticide were investigated. Male rat pups were anesthetized on postnatal day (PND) 15 with metofane and a radio transmitter (Data Sciences) was implanted in the abdominal cavity to monitor Tc and motor activity (MA). Two days were allowed for recovery. The PND 17 pups were then dosed by oral gavage with the OP chlorpyrifos (CHP) (1, 5, 10, or 15 mg/kg) or the CB carbaryl (CAR) (10, 20, 80, 120, or 160 mg/kg) or the corn oil vehicle. Pups were returned to their dams and littermates immediately after dosing and monitored for the next several days. CHP doses of 10 and 15 mg/kg resulted in 1.0 degrees C and 2.4 degrees C reductions in Tc, respectively. Tc recovered to control levels by approximately 16 h after dosing. There was significant mortality in rats dosed with 15 mg/kg CHP (6 of 11). CAR doses of 10 to 80 mg/kg had little effect on Tc. The highest dose of CAR (160 mg/kg) resulted in a 1.3 degrees C reduction in Tc that recovered in 9 h. In contrast, past studies found that adult male rats become hypothermic at CHP doses of >25 mg/kg, whereas a CAR dose of 50 mg/kg is effective at inducing hypothermia. Overall, it appears that during the development from preweanling to adult rat, there is a progressive attenuation in CHP-induced hypothermia. Conversely, CAR-induced hypothermia increases as a function of development.

Within- and between-home variability in indoor-air insecticide levels during pregnancy among an inner-city cohort from New York City

BACKGROUND

Residential insecticide use is widespread in the United States, but few data are available on the persistence and variability in levels in the indoor environment.

OBJECTIVE

The study aim was to assess within- and between-home variability in indoor-air insecticides over the final 2 months of pregnancy among a cohort of African-American and Dominican women from New York City.

METHODS

Women not employed outside the home were enrolled between February 2001 and May 2004 (n = 102); 9 insecticides and an adjuvant were measured in 48-hr personal air samples and 2-week integrated indoor air samples collected sequentially for 7.0 +/- 2.3 weeks (n = 337 air samples).

RESULTS

Sixty-one percent of the women reported using pest control during the air samplings. Chlorpyrifos, diazinon, and propoxur were detected in 99-100% of personal and indoor samples (range, 0.4-641 ng/m(3)). Piperonyl butoxide (a pyrethroid adjuvant) was detected in 45.5-68.5% (0.2-608 ng/m(3)). There was little within-home variability and no significant difference in air concentrations within homes over time (p > or = 0.2); between-home variability accounted for 88% of the variance in the indoor air levels of propoxur, 92% in chlorpyrifos, 94% in diazinon, and 62% in piperonyl butoxide (p < 0.001). Indoor and maternal personal air insecticide levels were highly correlated (r = 0.7-0.9, p < 0.001). Diazinon and chlorpyrifos levels declined 5-fold between 2001 and 2004 but were detected in all homes 1.5 and 2.5 years, respectively, after the U.S. Environmental Protection Agency ban on their residential use.

CONCLUSION

Results showed that the insecticides were persistent in the home with little variability in air concentrations over the 2 months and contributed to chronic maternal inhalation exposures during pregnancy.

Children's health in the rural environment

The rural environment is not as wholesome as some might think. In fact, smoking, drinking, illicit drug use, and obesity are more prevalent in rural than in urban youngsters. Childhood mortality is higher in rural areas, with drowning, motor vehicle accidents, firearm injuries, and farm machinery accidents as the leading causes. Air and water quality are monitored less and actually may be worse in the country than in urban areas. This article describes children's health problems associated with the rural environment and provides a list of resources for addressing these problems.

Use and storage of domestic pesticides in the UK

Several epidemiological studies, particularly from the United States, have suggested health concerns may arise from the chronic exposure of young children to pesticides in their home environment. Most of these studies are retrospective and the available pesticide exposure information is either subject to the problem of recall or derived from surrogate information. Currently, little is known about the extent of pesticide use in homes and gardens in the UK. This was investigated in this study using a sample of parents from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort in and around Bristol. The level and extent of pesticide use by parents was explored through interviews that took place at the homes of the participants during August to November 2001, followed by an inventory of products stored in the home. From the results, 93% of parents had used at least one pesticide over the preceding year with the highest use being in the garden, second inside the home, followed by treating pets and head lice. Most households reported using one to five different products over the past year, with a mean of 3.5. The frequency of pesticide use showed that a minority of parents are using pesticides in the high frequency range. Over 85 different pesticide products were found to be stored in 76% of homes, with 76 different types of pesticide active ingredients. Insecticides were the most commonly used and stored pesticide.

Use of point-of-sale data to track usage patterns of residential pesticides: methodology development

BACKGROUND

Residential-use pesticides have been shown to be a major source of pesticide exposure to people in the United States. However, little is understood about the exposures to household pesticides and the resultant health effects. One reason that little is known about home-use pesticide exposure is the lack of comprehensive data on exposures to pesticides in the home. One method to help ascertain the amount of pesticides present in the home is use of point-of-sale data collected from marketing companies that track product sales to obtain the volume of pesticides sold for home-use. This provides a measure of volume of home-use pesticide.

METHODS

We have constructed a searchable database containing sales data for home-use permethrin-containing pesticides sold by retail stores in the United States from January 1997 through December 2002 in an attempt to develop a tracking method for pesticide. This pilot project was conducted to determine if point-of-sale data would be effective in helping track the purchase of home-use permethrin containing pesticides and if it would stand as a good model for tracking sales of other home-use pesticides.

RESULTS

There are several limitations associated with this tracking method, including the availability of sales data, market coverage, and geographic resolution. As a result, a fraction of sales data potentially available for reporting is represented in this database. However, the database is sensitive to the number and type of merchants reporting permethrin sales. Further, analysis of the sale of individual products included in the database indicates that year to year variability has a greater impact on reported permethrin sales than the amount sold by each type of merchant.

CONCLUSION

We conclude that, while nothing could completely replace a detailed exposure assessment to estimate exposures to home-use pesticides, a point-of-sale database is a useful tool in tracking the purchase of these types of pesticides to 1) detect anomalous trends in regional and seasonal pesticide sales warranting further investigation into the potential causes of the trends; 2) determine the most commonly purchased application types; and 3) compare relative trends in sales between indoor and outdoor use products as well as compare trends in sales between different active ingredients.

Socio-demographic characteristics of UK families using pesticides and weed-killers

Pesticides are widely used in the home and garden to kill insects, weeds and other unwanted pests. There is mounting evidence that this usage may also have health consequences particularly on children. Using the ALSPAC cohort of 13,391 families with self-reported usage data up to age 4 years of the study child, the main users of pesticides appeared to be older, Caucasian, better educated, have higher incomes and more likely to own their home or to belong to non-manual social classes compared to less frequent users. There was some suggestion that different factors may affect weed-killer compared to other pesticide use. In particular, income appeared unrelated to other pesticide use. This may reflect different attitudes to indoor compared to garden applications. Alternatively, it may reflect whether the main user was the mother or the partner. Some authorities are currently encouraging domestic users to consider other non-chemical means of pest control before using pesticides. These results may help in targeting particular groups if further reductions in pesticide usage are desired. They have also helped in identifying the important confounders for adjusting future analyses on the potential health consequences of pesticides and weed-killers.

Organophosphate urinary metabolite levels during pregnancy and after delivery in women living in an agricultural community

Little information has been published about pesticide exposures experienced by pregnant women. We measured six dialkyl phosphate (DAP) urinary metabolites of organophosphate (OP) pesticides in 600 pregnant, low-income women living in the Salinas Valley, California, an agricultural area. A total of 28% were employed as farm fieldworkers during pregnancy, and 81% had at least one household member who worked in agriculture. Samples were collected twice during pregnancy (mean = 13 and 26 weeks' gestation, respectively) and just after delivery (mean = 9 days). As in other studies, dimethyldithiophosphate levels were higher than those of other urinary OP metabolites. Total DAP metabolite levels in samples collected after delivery were higher than in samples collected during pregnancy. Median metabolite levels at the first and second prenatal sampling points and at the postpartum collection were 102.8, 106.8, and 227.2 nmol/L, respectively. Both prenatal and postpartum metabolite levels were higher in these Salinas Valley women than in a sample of women of childbearing age in the general U.S. population (National Health and Nutrition Examination Survey), although the deviation from U.S. reference levels was most pronounced after delivery. Higher DAP metabolite levels in the immediate postpartum period may have implications for estimating dose during pregnancy and for exposure during lactation.

Insecticide urinary metabolites in nonoccupationally exposed populations

The wide use of insecticides in agricultural and residential settings has resulted in environmental contamination, leading to increased concern about exposure of the population and possible chronic effects on health. This review summarizes the studies that have measured urinary metabolites to assess exposure of nonoccupationally exposed population to nonpersistent insecticides, organophosphates (OPs), carbamates, and pyrethroids. Electronic search yielded 36 different studies performed in a small number of countries for the last 20 years, most of them dealing with OP urinary metabolites. Dialkylphosphates, specific metabolites of OPs, and specific metabolites of pyrethroids or carbamates, have been investigated. Results indicate that a wide range of the population, adults as well as children, is exposed to OPs and to a lesser extent to pyrethroids and carbamates. Levels are one to several orders of magnitude lower than those in occupational studies. The contribution of the different sources of insecticide exposure remains uncertain. Food contamination, as well as environmental and residential contamination, appears to influence exposure, especially in the case of children. Residential use of insecticides, having pets, and living near gardens or fields have all been inconstantly related to higher urinary metabolite levels. Occupational exposure of the parents, especially of the agricultural workers, seems to be a predictive factor of higher exposure of their children. More studies investigating every source and pathway of exposure of randomized population samples and in other countries than the United States, in particular in developing countries, could improve our knowledge of factors influencing insecticide exposure of the population.

Characterizing exposures to nonpersistent pesticides during pregnancy and early childhood in the National Children's Study: a review of monitoring and measurement methodologies

The National Children's Study is a proposed longitudinal cohort study to evaluate the relationships between children's health and the environment. Enrollment is estimated to begin in September 2005, and 100,000 children will be followed from preconception or early pregnancy until adulthood. Among multiple health outcomes, the study is proposing to investigate whether pre- and/or postnatal exposures to nonpersistent pesticides increase the risk of poor performance on neurobehavioral and cognitive exams during infancy and early childhood. Characterization of exposures will be challenging. Nonpersistent pesticides include many chemicals with biologic half-lives on the order of hours or days. Exposures can occur through multiple pathways (e.g., food and residential or agriculture pesticide use) and by multiple routes (inhalation, ingestion, dermal). Effects may depend on the developmental stage when exposure occurs. Sequential sampling is likely to be required and may involve a combination of environmental and biologic monitoring as well as collection of questionnaire data. In this article we review measurements that can be used to characterize exposures. These include biologic markers, personal and indoor air sampling techniques, collection of dust, surface and dermal wipe samples, and dietary assessment tools. Criteria for sample selection will necessitate evaluation of the time frame of exposure captured by the measurement in relationship to critical windows of susceptibility, the cost and validity of the measurements, participant burden, and variability in exposure routes across populations and at different age periods.

Patterns of pesticide use and their determinants among wives of farmer pesticide applicators in the Agricultural Health Study

Pesticide exposure among farmers' wives is poorly characterized. Using questionnaire data from a cohort study of licensed pesticide applicators and their spouses, we investigated patterns of pesticide use among farmers' wives (n = 31,173). Wives reported a wide range of pesticide use: 36% never used pesticides during their lifetimes, whereas the heaviest pesticide users (10%) reported lifetime use of 3 or more agricultural pesticides plus commonly used residential pesticides. We identified 5 ordinal pesticide-use categories and studied factors associated with each category through polytomous logistic regression. Engaging in field work and household hygiene practices that could increase exposure were associated with pesticide use, and associations appeared to strengthen with increasing pesticide use category. Farm women reporting the heaviest pesticide use could exacerbate their exposure by engaging in practices that could increase pesticide contact.

Outdoor, indoor, and personal exposure to VOCs in children

We measured volatile organic compound (VOC) exposures in multiple locations for a diverse population of children who attended two inner-city schools in Minneapolis, Minnesota. Fifteen common VOCs were measured at four locations: outdoors (O), indoors at school (S), indoors at home (H), and in personal samples (P). Concentrations of most VOCs followed the general pattern O approximately equal to S < P less than or equal to H across the measured microenvironments. The S and O environments had the smallest and H the largest influence on personal exposure to most compounds. A time-weighted model of P exposure using all measured microenvironments and time-activity data provided little additional explanatory power beyond that provided by using the H measurement alone. Although H and P concentrations of most VOCs measured in this study were similar to or lower than levels measured in recent personal monitoring studies of adults and children in the United States, p-dichlorobenzene was the notable exception to this pattern, with upper-bound exposures more than 100 times greater than those found in other studies of children. Median and upper-bound H and P exposures were well above health benchmarks for several compounds, so outdoor measurements likely underestimate long-term health risks from children's exposure to these compounds.

Personal, indoor, and outdoor VOC exposures in a probability sample of children

As part of the Minnesota Children's Pesticide Exposure Study we measured volatile organic compound (VOC) concentrations in a probability sample of households with children. The 6-day average concentrations for 10 common VOCs were obtained in urban and nonurban residences twice during this multiphase study: screening-phase indoor measurements were collected in 284 households, and in the intensive-phase matched outdoor (O), indoor (I), and personal (P) measurements were collected in a subset (N=72) of the screened households. Screening-phase households with smokers had significantly higher concentrations of benzene and styrene compared to nonsmoking households; households with an attached garage had significantly higher levels of benzene, chloroform, styrene, and m/p- and o-xylene compared to households without an attached garage; and nonurban residences, which had a greater prevalence of smokers and attached garages, had significantly higher 1,1,1-trichloroethane, styrene, and toluene and significantly lower tetrachloroethylene concentrations compared to urban households. The screening-phase weighted distributions estimate the mean and variability in indoor VOC concentrations for more than 45,000 households with children in the census tracts sampled. Overall, median indoor concentrations of most VOCs measured in this study were similar to or lower than indoor levels measured previously in the United States. Intensive-phase outdoor VOC concentrations were generally lower than other major metropolitan areas, but urban concentrations were significantly higher than nonurban concentrations for all compounds except 1,1,1-trichloroethylene. A consistent pattern of P>I>O was observed for nine of 10 VOCs, with 1,1,1-trichloroethylene (I>P>O) being the only exception to this pattern. For most children, the indoor at-home microevironment was strongly associated with personal exposure after controlling for important covariates, but the ratio of median to upper bound exposures was smaller than that observed in studies of adults. There are relatively little data on VOC exposures in children, so these results are useful for estimating the central tendency and distribution of VOC exposures in locations where children spend a majority of their time.

Regional variation in the incidence of symptomatic pesticide exposures: applications of geographic information systems

OBJECTIVE

To evaluate the epidemiology of symptomatic human pesticide exposures using poison control center data and geographic information systems.

METHODS

All symptomatic human pesticide exposures reported to the poison center during the period from January 1 to December 31, 2000 were included for analysis using geographic information systems. A space-time scan statistic was utilized to evaluate for clustering of symptomatic human exposures.

RESULTS

Of 322 symptomatic pesticide exposures, 297 (92%) contained spatial identifiers that could be further analyzed using geographic information systems. A spatial and temporal cluster of symptomatic pesticide exposures was identified during the periodfrom April 1 to August 31, 2000, covering a large geographic area of eastern and predominantly rural regions of the state. The relative risk of reporting a symptomatic pesticide exposure among individuals living within this geographic area was 1.8 (log likelihood ratio = 18.5, P = 0.0005).

CONCLUSIONS

Geographic information systems can be effectively utilized by poison control centers to study regional and temporal variation in the incidence of human pesticide exposures. With the collection of more specific spatial identifiers, geographic information systems may have many additional applications in the surveillance and prevention of pesticide and other sentinel event exposures.

Dietary exposure to chlorpyrifos and levels of 3,5,6-trichloro-2-pyridinol in urine

Information on associations between chlorpyrifos residues in food and personal exposure to chlorpyrifos would be valuable for evaluating the relationship between personal exposure and possible health effects. We used food consumption records, chlorpyrifos levels in duplicate plates, and measures of 3,5,6-trichloro-2-pyridinol (TCPy) in urine obtained from human volunteers in the National Human Exposure Assessment Survey in Maryland (NHEXAS-MD) to evaluate a food consumption-chemical residue model for estimating dietary intake of chlorpyrifos. Model inputs were the NHEXAS-MD food consumption records and chlorpyrifos residues in specific foods measured in the U.S. Food and Drug Administration Total Diet Study (TDS) market baskets from 1993 to 1997. The estimated mean and standard deviation of chlorpyrifos concentration (microg/kg) in duplicate plates (n=203) were within 20% and 50%, respectively, of the corresponding parameters of measured chlorpyrifos levels. However, predicted and measured concentrations in the 78 duplicate plates with detectable levels of chlorpyrifos were not significantly associated according to Spearman correlation analysis (r=0.04, p=0.7667) and linear regression (p=0.2726). Measured and estimated chlorpyrifos intakes for observations with non-zero values for each intake measure (n=71) were moderately associated on a rank (Spearman's r=0.24, p=0.0462) and linear basis (regression r(2)=0.07, p=0.0242). Measured intakes of chlorpyrifos from food and urinary TCPy were significantly correlated in rank order (n=87, Spearman's r=0.30, p=0.0041) and linear (n=87, Pearson's r=0.22, p=0.0409) analyses. Correlation coefficients between estimated intake of chlorpyrifos from food and TCPy were significantly different from zero (n=87; Spearman's r=0.22, p=0.0393; Pearson's r=0.21, p=0.0479). Comparing mean measured chlorpyrifos intake from food (0.46 microg/day) to mean estimated TCPy excretion via urine (6.3 microg/day), dietary intake of chlorpyrifos accounted for approximately 7% of TCPy in this population. These findings suggest the food consumption-chemical residue model can yield reasonably accurate estimates of the population distribution of dietary chlorpyrifos intake, but has little ability to predict dietary exposure for individuals; and that intake of chlorpyrifos from food is a minor contributor to TCPy in urine.