A total of 20 toxic, carcinogenic, or mutagenic organic compounds were measured in the air and drinking water of 355 residents of Bayonne and F.!izabeth. New Jersey, in the fall of 1981. The participants were selected from over 10,000 residents screened by a probability sampling technique to represent 128,000 persons (over the age of seven) who live in the two neighboring cities. Over one hμndred geographic areas throughout the two Cities were selected for monitoring. Each participant carried a personal sampler with him during his normal daily activities for two consecutive 12-h periods. (One resident in each of the 108 sampling segments had an identical sampler operating in the backyard for the same two 12-h periods.) All participants also collected two drinking water samples. At the end of the 24-h sampling period, all participants gave a sample of exhaled breath, which was analyzed for the same compounds. All partici­ pants also completed a questionnaire on their age, sex, occupations and activities during the sampling period. An extensive quality assurance program was carried out on all sampling/analysis activities. Eleven of the 20 chemicals were prevalent in air and 3 in water. Air was the most important pathway of exposure for 10 compounds, and drinking water was most important for 3 trihalomethanes. Ranges of exposures were extremely large, with differences of 3-4 orders of magnitude common. Median personal exposures were 2-5 times larger than median outdoor concentrations; maximum personal exposures were as much as 100 times corresponding maximum outdoor concentrations. Residence near major point sources had no effect on exposure but many common activities (filling a gas tank, visiting a dry cleaner, smoking) had significant effect on exposures.

The ability to infer human exposure to substances from drinking water using monitoring data helps determine and/or refine potential risks associated with drinking water consumption. We describe a survey sampling approach and its application to an atrazine groundwater monitoring study to adequately characterize upper exposure centiles and associated confidence intervals with predetermined precision. Study design and data analysis included sampling frame definition, sample stratification, sample size determination, allocation to strata, analysis weights, and weighted population estimates. Sampling frame encompassed 15 840 groundwater community water systems (CWS) in 21 states throughout the U. S. Median, and 95th percentile atrazine concentrations were 0.0022 and 0.024 ppb, respectively, for all CWS. Statistical estimates agreed with historical monitoring results, suggesting that the study design was adequate and robust. This methodology makes no assumptions regarding the occurrence distribution (e.g., lognormality); thus analyses based on the design-induced distribution provide the most robust basis for making inferences from the sample to target population.

A survey sampling approach is presented for estimating upper centiles of aggregate distributions of surface water pesticide measurements obtained from datasets with large sample sizes but variable sampling frequency. It is applied to three atrazine monitoring programs of Community Water Systems (CWS) that used surface water as their drinking water source: the nationwide Safe Drinking Water Act (SDWA) data, the Syngenta Voluntary Monitoring Program (VMP), and the Atrazine Monitoring Program (AMP).The VMP/AMP CWS were selected on the basis of atrazine monitoring history (CWS having at least one annual average concentration from SDWA ≥ 1.6 ppb atrazine since 1997 in the AMP). Estimates of the raw water 95th, 99th, and 99.9th centile atrazine concentrations for the VMP/AMP CWS are 4.82, 11.85, and 34.00 ppb, respectively. The corresponding estimates are lower for the finished drinking water samples, with estimates of 2.75, 7.94, and 22.66 ppb, respectively. Finished water centile estimates for the VMP/AMP CWS using only the SDWA data for these sites are consistent with the results. Estimates are provided for the April through July period and for CWS based on surface water source type (static, flowing, or mixed). Requisite sample sizes are determined using statistical tolerance limits, relative SE, and the Woodruff interval sample size criterion. These analyses provide 99.9% confidence that the existing data include the 99.9th centile atrazine concentration for CWS raw and finished water in the Midwest atrazine high-use areas and in the nationwide SDWA dataset. The general validity of this approach is established by a simulation that shows estimates to be close to target quantities for weights based on sampling probabilities or time intervals between samples. Recommendations are given for suitable effective sample sizes to reliably determine interval estimates.

The Environmental Protection Agency’s Detroit Exposure and Aerosol Research Study (DEARS) was a complex 3-year personal exposure study. The six geographically defined areas in the Detroit (Wayne County), Michigan, area used as study locations are ethnically diverse; the majority of the residents are African American or Hispanic. Each summer and winter season, the study solicited 40 adult nonsmoking study participants from these predefined areas. Participants were asked to allow home visits each morning for a week, to wear a personal exposure monitoring vest, and to complete an activity diary and follow-up questionnaire each day. Community action groups, recruitment staff, and environmental technicians coordinated the recruitment and environmental sampling activities. Although the study had an overall response rate of 19 percent, recruitment goals were met nearly every season in each geographic area. Over-recruitment was necessary to replace dropouts. Recruitment staff used face-to-face household recruitment to enroll 136 study participants. Among participants, 73 percent participated in two seasons. Details about the recruitment techniques used in exposure studies, as well as the lessons learned, rarely appear in the literature. This report delineates the lessons from the DEARS that may be beneficial to other researchers using similar study designs in low-income, ethnically diverse urban areas.

SS7-05 Introduction: The purpose of this work is to develop methods for collecting longitudinal data on human exposure-related activities. Methods and instruments are being developed for a broad range of data types: activity, location, energy expenditure, environmental conditions, diet, and use of 3 types of consumer products: pesticides, cleaning products, and personal care products. Integration of data streams through a common ambulatory platform is integral to our strategy for collecting information all day each day for a week. Our goal is to achieve low enough participant burden that people will sustain participation in longitudinal studies for 1 week in each quarter of the year. Methods: To relieve the participant burden of noting presence in residential microenvironments, we developed an automated monitoring system for indoor location tracking using Bluetooth wireless technology. Autonomous beacons are placed in key residential microenvironments (eg, kitchen, bedroom, bathroom, garage, vehicle) and range-adjusted to the perimeter of each room. The range is determined according to room size, beacon placement within the room, and potential interference with adjacent rooms. Throughout the 7-day monitoring session, each beacon periodically tests (eg, 30-econd intervals) whether the participant's pocket PC is within range. When the participant's pocket PC is detected, the beacon sends a time-stamped microenvironment location code to the pocket PC for data logging. The resulting data log records a weeklong history of the time spent in each residential microenvironment. Controlled bench tests are being conducted to establish reliability, longevity, sensitivity, and specificity of the tracking methodology. Observational field tests are being conducted by placing beacons in investigators’ homes and logging automated and manually affirmed presence in various rooms throughout the day. A pilot field test of our overall system, including location tracking, will be conducted during the spring of 2006. Five pilot test subjects will be randomly assigned to each of 8 experimental treatments. Each subject will participate for 7 consecutive days. Results: Results will be available after the controlled bench, observational field, and pilot field tests have been conducted in the spring of 2006. Discussion and Conclusions: Preliminary results have shown that automated detection is closely aligned with manual data. Technical elements of the system design will be presented, along with results of the various test methodologies. Results from this project will determine a set of collection methods that will produce accurate estimates of human exposure-related activities in future longitudinal studies.

The National Human Exposure Assessment Survey (NHEXAS) field study in EPA Region V (one of three NHEXAS field studies) provides extensive exposure data on a representative sample of 249 residents of the Great Lakes states. Concentration data were obtained for both metals and volatile organic compounds (VOCs) from multiple environmental media and from human biomarkers. A variance model for the logarithms of concentration measurements is used to define intraclass correlations between observations within primary sampling units (PSUs) (nominally counties) and within secondary sampling units (SSUs) (nominally Census blocks). A model for the total cost of the study is developed in terms of fixed costs and variable costs per PSU, SSU, and participant. Intraclass correlations are estimated for media and analytes with sufficient sample sizes. We demonstrate how the intraclass correlations and variable cost components can be used to determine the sample allocation that minimizes cost while achieving pre-specified precision constraints for future studies that monitor environmental concentrations and human exposures for metals and VOCs.

We used estimates derived from screener variables of the National Human Exposure Assessment Survey (NHEXAS) Phase I field study in EPA Region V (one of three NHEXAS Phase I field studies) to examine biases resulting from survey nonresponse and/or incomplete population coverage inherent in the study design. For variables with population values obtainable from Census projections, the combined effect of nonresponse and coverage bias was tested for after each stage of nonresponse using design-based weights. For variables where population values were not available as Census projections, nonresponse bias was tested for after the screener stage of nonresponse using weights adjusted for screener nonresponse. Additional tests for bias were performed using final survey weights to evaluate the performance of survey weight adjustments in reducing observed bias. Comparison of biases estimated using both design-based and adjusted weights was used to identify potentially important weight adjustment variables for future exposure studies, identify possible weaknesses in survey design strategies, and support the use of nonresponse and poststratification weight adjustments to reduce bias in future survey studies.

The Minnesota Children's Pesticide Exposure Study (MNCPES) provides exposure, environmental, and biologic data relating to multipathway exposures of children for four primary pesticides (chlorpyrifos, malathion, diazinon, and atrazine), 14 secondary pesticides, and 13 polynuclear aromatic hydrocarbons (PAHs). Monitoring was performed on a probability-based sample of 102 children aged 3–12 in Minneapolis/St. Paul and in a nearby rural area (Goodhue and Rice counties). This paper provides estimated distributions of this population's exposures and exposure-related measurements and examines associations among the various measures via rank (Spearman) correlations. In addition, it provides some aggregate and cumulative exposure estimates for pesticides, and compares the relative intakes from inhalation and dietary ingestion. Intakes for the four primary pesticides appeared to come principally from the ingestion rather than the inhalation route; this was clearly true for chlorpyrifos but was less certain for the other three primary pesticides because of their higher degree of nondetects. Solid food rather than beverages was clearly the main contributor to the ingestion intake. Despite the dominance of the ingestion route, the urinary metabolite of chlorpyrifos exhibited a stronger association with the air measurements than with the dietary measures. Personal-air samples exhibited strong rank correlations with indoor air samples for chlorpyrifos, malathion, and diazinon (0.81, 0.51, and 0.62, respectively), while personal-air atrazine levels correlated well with outdoor levels (0.69); personal-air diazinon levels also correlated well with outdoor levels (0.67). For the PAHs, many significant associations were evident among the various air samples and for the air samples with the dust samples, especially for those compounds with consistently high percent measurable values (particularly fluoranthene, phenanthrene, and pyrene).

The purpose of this manuscript is to describe the practical strategies developed for the implementation of the Minnesota Children's Pesticide Exposure Study (MNCPES), which is one of the first probability-based samples of multi-pathway and multi-pesticide exposures in children. The primary objective of MNCPES was to characterize children's exposure to selected pesticides through a combination of questionnaires, personal exposure measurements (i.e., air, duplicate diet, hand rinse), and complementary monitoring of biological samples ( i.e., pesticide metabolites in urine), environmental samples ( i.e., residential indoor/outdoor air, drinking water, dust on residential surfaces, soil), and children's activity patterns. A cross-sectional design employing a stratified random sample was used to identify homes with age-eligible children and screen residences to facilitate oversampling of households with higher potential exposures. Numerous techniques were employed in the study, including in-person contact by locally based interviewers, brief and highly focused home visits, graduated subject incentives, and training of parents and children to assist in sample collection. It is not feasible to quantify increases in rates of subject recruitment, retention, or compliance that resulted from the techniques employed in this study. Nevertheless, results indicate that the total package of implemented procedures was instrumental in obtaining a high percentage of valid samples for targeted households and environmental media.

Although children are exposed to a variety of environmental hazards, including pesticides, there is a scarcity of information available to estimate exposures realistically. This article reports on one of the first attempts to measure multi-pathway pesticide exposures in a population-based sample of urban and non-urban children. A design strategy was developed to assess multi-pathway pesticide exposures in children using personal exposure measurements in combination with complimentary measurements of biological markers of exposure, concentrations in relevant environmental media, and time spent in important microenvironments and participating in exposure-related activities. Sample collection and analysis emphasized measurement of three insecticides (i.e., chlorpyrifos, diazinon, and malathion) and one herbicide (i.e., atrazine). These compounds were selected because of their frequent use, presence in multiple environmental media, expected population exposures, and related hazard/toxicity. The study was conducted during the summer of 1997 in Minnesota and involved a stratified sample of households with children ages 3–12 years. Participants resided in either (a) the cities of Minneapolis and St. Paul (urban households), or (b) Rice and Goodhue Counties just south of the metropolitan area (non-urban households). Results from a residential inventory documenting storage and use of products containing the target pesticides were used to preferentially select households where children were likely to have higher exposures. The study successfully obtained pesticide exposure data for 102 children, including measurements of personal exposures (air, hand rinse, duplicate diet), environmental concentrations (residential indoor/outdoor air, drinking water, residential surfaces, soil), activity patterns (obtained by questionnaire, diary, videotaping), and internal dose (metabolites in urine).

As part of the National Human Exposure Assessment Survey (NHEXAS), residential pesticide storage and use patterns were evaluated in a population-based sample of Minnesota households with children aged 3–13. In-home interviews and inventories were conducted to identify pesticide products stored and used in and around 308 households. This statistically based sample represents more than 49,000 urban and rural households in the census tracts sampled. More than 850 unique products were identified using Environmental Protection Agency (EPA) registration numbers. Pesticide products were found in 97% and reported used in 88% of study households. Population-weighted mean values for pesticide storage and use were 6.0 and 3.1 products per household, respectively. The most common active ingredients found were diethyl toluamide (DEET) and related compounds, piperonyl butoxide, pyrethrins, dimethylamine 2-[2-methyl-4-chlorophenoxy] propionate (MCPA) and chlorpyrifos. Household socio-demographic characteristics explained little of the variability in pesticide storage and use patterns, and there were no significant differences in residential storage and use patterns between households located in urban versus non-urban census tracts. Although the prevalence of households with pesticide products was similar to recent national surveys, observed storage and use rates were almost twice those obtained in recent national studies, reflecting improved inventory techniques used by this study and/or increased rates of pesticide presence and use in study households.

Research Triangle Institute, Research Triangle Park, N.C., USA 27709; James Quackenboss. U.S. EPA. Las Vegas, NV 89193, USA; Ken Sexton, University of Minnesota, Minneapolis, MN, USA 55455; Pamela Shubat, Minnesota Department of Health, MN Department of Health 121 East 7th Place, Suite 220, St Paul, MN 55101, USA.

The frequency of occurrence of alachlor and several other agrichemicals in water from private, rural domestic wells was determined for all counties in the United States where alachlor is sold. The three-stage, stratified, unequal probability selection procedure yielded water samples from 1430 wells in 89 counties. Of the estimated 6 million existing private domestic wells in the target area, less than 1% have detectable levels of alachlor. Similar occurrence frequencies were found for metolachlor and simazine. Atrazine was the most commonly detected pesticide in the alachlor use area with an occurrence frequency near 12%. Concentrations of all detected pesticides in rural well water are very low and are rarely expected to exceed any health-based standard. The occurrence of nitrate/nitrite, however, is more common. Over 50% of the wells in the alachlor use area have detectable levels of nitrate/nitrite. Nearly 5% exceed the 10 mg/L maximum contaminant level for nitrate/nitrite (expressed as total nitrogen). The occurrence of all chemicals is correlated with various measures of chemical use near the well and with measures of groundwater vulnerability. The likelihood of finding other agrichemicals in a well is significantly increased when nitrate and atrazine are also present.

AbstractGround water studies that require long data collection periods may be affected by temporal changes in ground water chemistry. Seasonal fluctuations in ground water chemistry are particularly apparent in shallow aquifers. Of specific interest is the inclusion of temporal variability in the design of statistical surveys of agricultural chemicals in well water. Statistical treatment of temporal variability involves selecting a probability sample from temporal units. The selection strategy may include repeating the same spatial units in each temporal stratum or choosing an independent sample of spatial units for each temporal stratum. The appropriate strategy depends on the specific study objectives. Failure to account for temporal variability may compromise the validity of study conclusions. An example of a large‐scale retrospective survey designed to estimate temporal averages of water quality across all wells is presented.

The TEAM Study measured exposures to 20-25 volatile organic compounds in the air, drinking water, and exhaled breath of 650 persons in 4 states. Volume I is a summary and overview of the entire study. Volume II deals with studies in New Jersey, North Carolina, and North Dakota. Volume III deals with studies in California. Volume IV presents the Standard Operations Procedures employed in the study. Major findings include: (1) personal monitors and breath spirometers employing Tenax adsorbents are sensitive and adequately precise instruments to determine normal daily exposures of the general public; (2) personal and indoor exposures generally exceeded outdoor concentrations; (3) major sources of exposure include occupations, smoking, visiting dry cleaners, and filling gas tanks.