Bryan L. Williams

Urinary Concentrations of Metabolites of Pyrethroid Insecticides in the General U.S. Population: National Health and Nutrition Examination Survey 1999–2002

Background Pyrethroid insecticides are the most commonly used residential insecticides in the United States. Objectives Our objective was to assess human exposure via biomonitoring to pyrethroid insecticides in a representative sample of the general U.S. population ≥ 6 years of age. Methods By using isotope-dilution high-performance liquid chromatography/electrospray chemical ionization/tandem mass spectrometry, we measured five urinary metabolites of pyrethroid insecticides in 5,046 samples collected as a part of the 1999–2002 National Health and Nutrition Examination Survey (NHANES). Univariate, multivariate, and Pearson correlation analyses were performed using SUDAAN and SAS software, incorporating the appropriate sample weights into the analyses. Multivariate analyses included age, sex, race/ethnicity, creatinine, fasting status, and urine collection time as covariates. Results We detected 3-phenoxybenzoic acid (3PBA), a metabolite common to many pyrethroid insecticides, in more than 70% of the samples. The least-squares geometric mean (LSGM) concentration (corrected for covariates) of 3PBA and the frequency of detection increased from 1999–2000 (0.292 ng/mL) to 2001–2002 (0.318 ng/mL) but not significantly. Non-Hispanic blacks had significantly higher LSGM 3PBA concentrations than did non-Hispanic whites and Mexican Americans in the 2001–2002 survey period and in the combined 4-year survey periods but not in the 1999–2000 survey period. Children had significantly higher LSGM concentrations of 3PBA than did adolescents in both NHANES periods and than adults in NHANES 1999–2000. Cis- and trans-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid were highly correlated with each other and with 3PBA, suggesting that urinary 3PBA was derived primarily from exposure to permethrin, cypermethrin, or their degradates. Conclusions Pyrethroid insecticide exposure in the U.S. population is widespread, and the presence of its metabolites in the urine of U.S. residents indicates that children may have higher exposures than adolescents and adults.

Determinants of Trust Perceptions among Residents Surrounding the Savannah River Nuclear Weapons Site

The public is becoming increasingly distrustful of hazardous waste management activities. However, public trust is a requisite condition for effective environmental management of hazardous waste sites. Without trust, it is unlikely that such institutions can effectively convince the public that a site is safe and can be reused. The authors of this article conducted a study of the social, economic, psychological, demographic, and political factors that may affect environmental risk assessment and communication at the U.S. Department of Energy’s Savannah River Nuclear Weapons Site (SRS). Public trust was a central focus of this study. A population survey was conducted to evaluate the level of public mistrust and correlates of public mistrust among residents living near the SRS. In this sample, several groups of respondents demonstrated high levels of trust. Respondents living upriver from SRS and respondents whose county was economically dependent on SRS voiced high levels of trust. Respondents who were predisposed toward accepting additional hazardous waste or accepting public health risks for economic gain also showed high levels of trust. Findings suggest that public trust is influenced by a variety of factors including personal traits, experiences, and economic needs.

Risk Perception in Context: The Savannah River Site Stakeholder Study

Environmental managers are increasingly charged with involving the public in the development and modification of policies regarding risks to human health and the environment. Involving the public in environmental decision making first requires a broad understanding of how and why the public perceives various risks. The Savannah River Stakeholder Study was conducted with the purpose of investigating individual, economic, and social characteristics of risk perceptions among those living near the Savannah River Nuclear Weapons Site. A number of factors were found to impact risk perceptions among those living near the site. Ones estimated proximity to the site and relative river location surfaced as strong determinants of risk perceptions among SRS residents. Additionally, living in a quality neighborhood and demonstrating a willingness to accept health risks for economic gain strongly abated heightened risk perceptions.

Urinary Concentrations of Dialkylphosphate Metabolites of Organophosphorus Pesticides: National Health and Nutrition Examination Survey 1999–2004

Organophosphorus (OP) insecticides were among the first pesticides that EPA reevaluated as part of the Food Quality Protection Act of 1996. Our goal was to assess exposure to OP insecticides in the U.S. general population over a six-year period. We analyzed 7,456 urine samples collected as part of three two-year cycles of the National Health and Nutrition Examination Survey (NHANES) from 1999–2004. We measured six dialkylphosphate metabolites of OP pesticides to assess OP pesticide exposure. In NHANES 2003–2004, dimethylthiophosphate was detected most frequently with median and 95th percentile concentrations of 2.03 and 35.3 μg/L, respectively. Adolescents were two to three times more likely to have diethylphosphate concentrations above the 95th percentile estimate of 15.5 μg/L than adults and senior adults. Conversely, for dimethyldithiophosphate, senior adults were 3.8 times and 1.8 times more likely to be above the 95th percentile than adults and adolescents, respectively, while adults were 2.1 times more likely to be above the 95th percentile than the adolescents. Our data indicate that the most vulnerable segments of our population—children and older adults—have higher exposures to OP pesticides than other population segments. However, according to DAP urinary metabolite data, exposures to OP pesticides have declined during the last six years at both the median and 95th percentile levels.

Metal exposures in an inner-city neonatal population

OBJECTIVES We measured concentrations of lead (Pb), manganese (Mn), chromium (Cr), and copper (Cu) in umbilical cord whole blood and examined sources of environmental Pb exposures in a predominantly African-American population. METHODS Between April and July 2006, we collected reproductive histories, questionnaires, and blood samples from 102 women, aged 16-45 years, who delivered at a Memphis, TN hospital. RESULTS The prevalence of preeclampsia and low birth weight infancy in the study population was 11% and 10%, respectively. Twenty-eight percent of mothers reported living near a potential Pb-contaminated area, while 43% lived in a residence built before 1978. Geometric mean (GM) concentrations for umbilical cord blood in the study population were 1.3, 3.5, 9.0, and 52.0 microg/dL for Pb, Mn, Cr, and Cu, respectively. Six neonates had cord blood Pb (CBL) concentrations above 10 microg/dL, while 20 had CBL concentrations > or =2 microg/dL. GM umbilical CBL levels were higher in neonates born to women living near a potential Pb-contaminated area (2.2 vs. 1.1 microg/dL) and those with friends, family or household members exposed to lead products (1.6 vs. 1.1 microg/dL). Some evidence of an exposure-response relationship was also detected between all four metal concentrations and an increasing number of maternal lead exposures. After adjustment for confounding, proximity to a Pb-contaminated area was the strongest environmental determinant of CBL levels among neonates with CBL concentrations of > or =2 microg/dL (odds ratio=5.1; 95% CI=1.6, 16.7). CONCLUSIONS Metal concentrations were elevated in this population, and CBL levels were associated with proximity to Pb-contaminated areas.

GEOGRAPHICAL DIMENSIONS AND CORRELATES OF TRUST

A sample of 323 residents of New Jersey stratified by neighborhood quality (excellent, good, fair, poor) was gathered to determine if trust in science and technology to protect public health and environment at the societal scale was associated with trust of the local officials, such as the mayor, health officer, developers, mass media, and legislators who are guardians of the local environment. Societal (trust of science and technology) and neighborhood (mayor, health officer) dimensions of trust were found. These societal and neighborhood trust dimensions were weakly correlated. Respondents were divided into four trust-of-authority groups: high societal-high neighborhood, low societal-low neighborhood, high societal-low neighborhood, and low societal-high neighborhood. High societal-high neighborhood trust respondents were older, had lived in the neighborhoods for many years, were not troubled much by neighborhood or societal environmental threats, and had a strong sense of control over their environment. In strong contrast, low societal-low neighborhood trust respondents were relatively young, typically had lived in their present neighborhood for a short time, were troubled by numerous neighborhood and societal environmental threats, did not practice many personal public health practices, and felt little control over their environment.

Inter- and intra-ethnic variation in water intake, contact, and source estimates among Tucson residents: Implications for exposure analysis.

Water-related exposures among Hispanics, particularly among Mexican Americans, are relatively unknown. Exposure and risk assessment is further complicated by the absence of good time–activity data (e.g., water intake) among this population. This study attempts to provide some insight concerning water-related exposure parameters among Hispanics. Determining the extent to which non-Hispanic whites and Hispanics living in the Tucson metropolitan area differ with respect to direct water intake and source patterns is the primary purpose of this investigation. Using random digit dialing, researchers conducted a cross-sectional telephone population survey of 1183 Tucson residents. Significant ethnic variation was observed in water intake patterns among this sample, particularly in terms of source. Hispanics reported much higher rates of bottled water consumption than did non-Hispanic whites. Ethnic variation in exposure parameters such as that observed in this study increases the potential for measurement error in exposure analysis. Erroneous assumptions that exposure estimates (i.e., water intake source) are generalizable across various ethnic groups may lead to both overestimation and underestimation of contaminant exposure.

Hierarchical Linear Models of Factors Associated with Public Participation among Residents Living near the US Army's Chemical Weapons Stockpile Sites

The purpose of this study was to investigate public involvement among residents living near the US Armys eight Chemical Weapons Stockpile sites. A cross-sectional study was conducted across 10 states. Primary data were obtained through a random digit dialling population survey. The study sample consisted of 8315 residents living within emergency response zones surrounding the US Armys Chemical Weapons Stockpile sites. Three research questions were investigated: (1) to what extent respondents participated in specific civic activities, and to what extent respondents intended to participate in site-related decisions; (2) to what extent psychological, social, economic and programmatic factors influenced a respondents civic participation or personal intent to participate; and (3) to what extent a respondents civic participation or personal intent to participate were individually or contextually determined. Residents in this sample exhibited moderately high levels of civic participation. Overall, residents across the sites did not differ greatly with respect to either civic participation or the intent to participate. Civic participation was primarily associated with educational attainment and family size. The intent to participate was primarily associated with the following individual variables: perceived technological attributes; perceived risk; perceived impact; perceptions towards public outreach; educational attainment; and gender. In terms of community variables, the intent to participate was also indirectly associated with the number of activist groups.

Assessing the impact of the local environment on birth outcomes: a case for HLM.

Hierarchical linear Models (HLM) is a useful way to analyze the relationships between community level environmental data, individual risk factors, and birth outcomes. With HLM we can determine the effects of potentially remediable environmental conditions (e.g., air pollution) after controlling for individual characteristics such as health factors and socioeconomic factors. Methodological limitations of ecological studies of birth outcomes and a detailed analysis of the varying models that predict birth weight will be discussed. Ambient concentrations of criterion air pollutants (e.g., lead and sulfur dioxide) demonstrated a sizeable negative effect on birth weight; while the economic characteristics of the mothers residential census tract (ex. poverty level) also negatively influenced birth weight.

Oregon indigenous farmworkers: results of promotor intervention on pesticide knowledge and organophosphate metabolite levels.

Objectives: To examine changes in health beliefs, pesticide safety knowledge, and biomarkers of pesticide exposure in indigenous farmworkers who received enhanced pesticide safety training compared with those receiving the standard training. Methods: Farmworkers in Oregon were randomly assigned to either a promotors pesticide safety training program or a standard video-based training. Spot urine samples were analyzed for dialkyl phosphate urinary metabolites. Pre-/postintervention questionnaires were used to measure pesticide safety knowledge, health beliefs, and work practices. Results: Baseline to follow-up improvements in total pesticide knowledge scores were higher in the promotor group than in the standard video group. Pairwise differences in mean concentrations of dialkyl phosphate metabolite levels showed declines from baseline to follow-up for both intervention groups. Conclusions: Results showed reductions in pesticide exposure in indigenous-language speaking farmworkers who received enhanced pesticide safety training.