Probabilistic approach to residential vapor intrusion exposure screening for Chlorinated Volatile Organic Compounds: a case study in San Antonio,Texas

The potential for subsurface volatile chemicals to migrate through the soil and impact indoor air quality is an increasingly important exposure pathway at contaminated sites. The characterization of this pathway is highly uncertain and dependent upon many site and building-specific parameters. A probability house-by-house model, based on the Johnson-Ettinger algorithm, is developed based on the current and historic conditions of groundwater contamination of tricholorethylene and tetrachlorethylene from activities at the former Kelly Air Force Base in San Antonio, Texas. The analysis suggests that historically 5.5% of houses exceed PCE screening levels (0.41 ug/m3) at the mean level and 85.3% at the 95th percentile; for TCE (at 0.25 ug/m3) it is 49% and 99% respectively. The current EPA model is slightly less conservative than the new parameterization by Johnson (2005). Comparison with measured samples suggests the probabilistic model underestimates exposure. Soil properties and air exchange rates are the most input critical parameters

Assessing Exposure to Chlorinated Solvents from the Subsurface to Indoor Air Pathway

The migration of chlorinated volatile organic compounds from groundwater to indoor air--known as vapor intrusion--is an important exposure pathway at sites with contaminated groundwater. However, monitoring indoor air quality in the hundreds or thousands of at-risk homes at each site is logistically and financially infeasible. Screening methods are needed to prioritize homes for monitoring and remediation. Current screening approaches do not adequately account for the substantial spatial and temporal variability in vapor intrusion risk, in part because the causes of this variability are not well understood. This work explores variability in vapor intrusion risk in a case-study community and then develops two different modeling approaches for screening at-risk homes. We employed a community-based approach to collect indoor air samples and analyze vapor intrusion risk in 20 homes at a case-study site. Results demonstrate that indoor concentrations of tetrachloroethylene from vapor intrusion vary by an order of magnitude across space and time. We show that key factors affecting this variability include barometric pressure drop, humidity, wind speed, and season. Using data collected from 370 homes in the National Database on Vapor Intrusion, we developed a multilevel regression model to predict vapor intrusion risks in unmonitored homes. The resulting predictions decrease the rate of false negatives compared with the U.S. Environmental Protection Agency's (EPA) current screening approach, which assumes that indoor air concentration will not exceed 1/1,000 times the soil gas concentration just above the groundwater. Finally, we demonstrate a second approach for improving the accuracy of screening by using Bayesian statistical techniques to integrate observational data into a mechanistic model describing the physical and chemical processes driving vapor intrusion. The resulting calibrated model also decreases the rate of false negatives in screening homes for vapor intrusion risks when compared with the current EPA approach. The results suggest current policy may underestimate vapor intrusion exposures, and we demonstrate two approaches to improve exposure assessment. Future research should evaluate the potential for community-centered and real-time monitoring devices, the integration of localized and cumulative risk information into the framework, and assessment of the risks and benefits of a precautionary approach to mitigation.Doctor of Philosoph

Low-Cost Air Quality Monitoring Tools: From Research to Practice (A Workshop Summary).

In May 2017, a two-day workshop was held in Los Angeles (California, U.S.A.) to gather practitioners who work with low-cost sensors used to make air quality measurements. The community of practice included individuals from academia, industry, non-profit groups, community-based organizations, and regulatory agencies. The group gathered to share knowledge developed from a variety of pilot projects in hopes of advancing the collective knowledge about how best to use low-cost air quality sensors. Panel discussion topics included: (1) best practices for deployment and calibration of low-cost sensor systems, (2) data standardization efforts and database design, (3) advances in sensor calibration, data management, and data analysis and visualization, and (4) lessons learned from research/community partnerships to encourage purposeful use of sensors and create change/action. Panel discussions summarized knowledge advances and project successes while also highlighting the questions, unresolved issues, and technological limitations that still remain within the low-cost air quality sensor arena

Applying the behaviour change technique (BCT) taxonomy v1: a study of coder training.

Behaviour Change Technique Taxonomy v1 (BCTTv1) has been used to detect active ingredients of interventions. The purpose of this study was to evaluate effectiveness of user training in improving reliable, valid and confident application of BCTTv1 to code BCTs in intervention descriptions. One hundred sixty-one trainees (109 in workshops and 52 in group tutorials) were trained to code frequent BCTs. The following measures were taken before and after training: (i) inter-coder agreement, (ii) trainee agreement with expert consensus, (iii) confidence ratings and (iv) coding competence. Coding was assessed for 12 BCTs (workshops) and for 17 BCTs (tutorials). Trainees completed a course evaluation. Methods improved agreement with expert consensus (p < .05) but not inter-coder agreement (p = .08, p = .57, respectively) and increased confidence for BCTs assessed (both p < .05). Methods were as effective as one another at improving coding competence (p = .55). Training was evaluated positively. The training improved agreement with expert consensus, confidence for BCTs assessed, coding competence but not inter-coder agreement. This varied according to BCT.This work was carried out as part of the Behavior Change Technique Taxonomy project funded by the Medical Research Council via its Methodology panel [G0901474/1].This is the accepted manuscript version. The final publication is available from Springer at http://link.springer.com/article/10.1007%2Fs13142-014-0290-

Transient Hypoxia Alters Striatal Catecholamine Metabolism in Immature Brain: An In Vivo Microdialysis Study

Microdialysis probes were inserted bilaterally into the striatum of 7-day-old rat pups (n = 30) to examine extracellular fluid levels of dopamine, its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA). The dialysis samples were assayed by HPLC with electrochemical detection. Baseline levels, measured after a 2-h stabilization period, were as follows: dopamine, not detected; DOPAC, 617 ± 33 fmol/min; HVA, 974 ± 42 fmol/min; and 5-HIAA, 276 ± 15 fmol/min. After a 40-min baseline sampling period, 12 animals were exposed to 8% oxygen for 120 min. Hypoxia produced marked reductions in the striatal extracellular fluid levels of both dopamine metabolites ( p < 0.001 by analysis of variance) and a more gradual and less prominent reduction in 5-HIAA levels ( p < 0.02 by analysis of variance), compared with controls (n = 12) sampled in room air. In the first hour after hypoxia, DOPAC and HVA levels rose quickly, whereas 5-HIAA levels remained suppressed. The magnitude of depolarization-evoked release of dopamine (elicited by infusion of potassium or veratrine through the microdialysis probes for 20 min) was evaluated in control and hypoxic animals. Depolarization-evoked dopamine efflux was considerably higher in hypoxic pups than in controls: hypoxic (n = 7), 257 ± 32 fmol/min; control (n = 12), 75 ± 14 fmol/min ( p < 0.001 by analysis of variance). These data demonstrate that a brief exposure to moderate hypoxia markedly disrupts striatal catecholamine metabolism in the immature rodent brain.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66218/1/j.1471-4159.1990.tb01914.x.pd

Reducing Emergency Department Visits for Acute Gastrointestinal Illnesses in North Carolina (USA) by Extending Community Water Service

BACKGROUND: Previous analyses have suggested that unregulated private drinking water wells carry a higher risk of exposure to microbial contamination than regulated community water systems. In North Carolina, ~35% of the state's population relies on private wells, but the health impact associated with widespread reliance on such unregulated drinking water sources is unknown. OBJECTIVES: We estimated the total number of emergency department visits for acute gastrointestinal illness (AGI) attributable to microbial contamination in private wells in North Carolina per year, the costs of those visits, and the potential health benefits of extending regulated water service to households currently relying on private wells for their drinking water. METHODS: We developed a population intervention model using 2007-2013 data from all 122 North Carolina emergency departments along with microbial contamination data for all 2,120 community water systems and for 16,138 private well water samples collected since 2008. RESULTS: An estimated 29,400 (95% CI: 26,600, 32,200) emergency department visits per year for acute gastrointestinal illness were attributable to microbial contamination in drinking water, constituting approximately 7.3% (95% CI: 6.6, 7.9%) of all AGI-related visits. Of these attributable cases, 99% (29,200; 95% CI: 26,500, 31,900) were associated with private well contamination. The estimated statewide annual cost of emergency department visits attributable to microbiological contamination of drinking water is 40.2 million USD (95% CI: 2.58 million USD, 193 million USD), of which 39.9 million USD (95% CI: 2.56 million USD, 192 million USD) is estimated to arise from private well contamination. An estimated 2,920 (95% CI: 2,650, 3,190) annual emergency department visits could be prevented by extending community water service to 10% of the population currently relying on private wells. CONCLUSIONS: This research provides new evidence that extending regulated community water service to populations currently relying on private wells may decrease the population burden of acute gastrointestinal illness. CITATION: DeFelice NB, Johnston JE, Gibson JM. 2016. Reducing emergency department visits for acute gastrointestinal illnesses in North Carolina (USA) by extending community water service. Environ Health Perspect 124:1583-1591; http://dx.doi.org/10.1289/EHP160

Vitamin D status is heritable and under environment‐dependent selection in the wild

Vitamin D has a well‐established role in skeletal health and is increasingly linked to chronic disease and mortality in humans and companion animals. Despite the clear significance of vitamin D for health and obvious implications for fitness under natural conditions, no longitudinal study has tested whether the circulating concentration of vitamin D is under natural selection in the wild. Here, we show that concentrations of dietary‐derived vitamin D(2) and endogenously produced vitamin D(3) metabolites are heritable and largely polygenic in a wild population of Soay sheep (Ovis aries). Vitamin D(2) status was positively associated with female adult survival, and vitamin D(3) status predicted female fecundity in particular, good environment years when sheep density and competition for resources was low. Our study provides evidence that vitamin D status has the potential to respond to selection, and also provides new insights into how vitamin D metabolism is associated with fitness in the wild

Maternal Cadmium Levels during Pregnancy Associated with Lower Birth Weight in Infants in a North Carolina Cohort

Cadmium (Cd) is a ubiquitous environmental contaminant, a known carcinogen, and understudied as a developmental toxicant. In the present study, we examined the relationships between Cd levels during pregnancy and infant birth outcomes in a prospective pregnancy cohort in Durham, North Carolina. The study participants (n = 1027) had a mean Cd level of 0.46 µg/L with a range of <0.08 to 2.52 µg/L. Multivariable models were used to establish relationships between blood Cd tertiles and fetal growth parameters, namely birth weight, low birth weight, birth weight percentile by gestational age, small for gestational age, pre-term birth, length, and head circumference. In multivariable models, high maternal blood Cd levels (≥0.50 µg/L) during pregnancy were inversely associated with birth weight percentile by gestational age (p = 0.007) and associated with increased odds of infants being born small for gestational age (p<0.001). These observed effects were independent of cotinine-defined smoking status. The results from this study provide further evidence of health risks associated with early life exposure to Cd among a large pregnancy cohort

The genomic basis of mood instability:identification of 46 loci in 363,705 UK Biobank participants, genetic correlation with psychiatric disorders, and association with gene expression and function

Genome-wide association studies (GWAS) of psychiatric phenotypes have tended to focus on categorical diagnoses, but to understand the biology of mental illness it may be more useful to study traits which cut across traditional boundaries. Here, we report the results of a GWAS of mood instability as a trait in a large population cohort (UK Biobank, n = 363,705). We also assess the clinical and biological relevance of the findings, including whether genetic associations show enrichment for nervous system pathways. Forty six unique loci associated with mood instability were identified with a SNP heritability estimate of 9%. Linkage Disequilibrium Score Regression (LDSR) analyses identified genetic correlations with Major Depressive Disorder (MDD), Bipolar Disorder (BD), Schizophrenia, anxiety, and Post Traumatic Stress Disorder (PTSD). Gene-level and gene set analyses identified 244 significant genes and 6 enriched gene sets. Tissue expression analysis of the SNP-level data found enrichment in multiple brain regions, and eQTL analyses highlighted an inversion on chromosome 17 plus two brain-specific eQTLs. In addition, we used a Phenotype Linkage Network (PLN) analysis and community analysis to assess for enrichment of nervous system gene sets using mouse orthologue databases. The PLN analysis found enrichment in nervous system PLNs for a community containing serotonin and melatonin receptors. In summary, this work has identified novel loci, tissues and gene sets contributing to mood instability. These findings may be relevant for the identification of novel trans-diagnostic drug targets and could help to inform future stratified medicine innovations in mental health