Gulls are often cited as important contributors of fecal contamination to surface waters, and some recreational beaches have used gull control measures to improve microbial water quality. In this study, gulls were chased from a Lake Michigan beach using specially trained dogs, and water quality improvements were quantified. Fecal indicator bacteria and potentially pathogenic bacteria were measured before and during gull control using culture methods and quantitative polymerase chain reaction (qPCR). Harassment by dogs was an effective method of gull control: average daily gull populations fell from 665 before to 17 during intervention; and a significant reduction in the density of a gull-associated marker was observed (p < 0.001). Enterococcus spp. and Escherichia coli densities were also significantly reduced during gull control (p < 0.001 and p = 0.012, respectively for culture methods; p = 0.012 and p = 0.034, respectively for qPCR). Linear regression results indicate that a 50% reduction in gulls was associated with a 38% and 29% decrease in Enterococcus spp. and E. coli densities, respectively. Potentially human pathogenic bacteria were detected on 64% of days prior to gull control and absent during gull intervention, a significant reduction (p = 0.005). This study demonstrates that gull removal can be a highly successful beach remedial action to improve microbial water quality.

Methyl tertiary butyl ether (MTBE) has been proposed and is being used as an additive to increase the octane of gasoline without the use of tetraethyl lead and alkylbenzenes. The present experiments have been performed to examine the kinetics and mechanisms of the atmospheric removal of MTBE. The kinetics of the reaction of OH with MTBE was examined by using a relative rate technique in which photolysis of methyl nitrite was used as the source of OH. With n‐butane as the reference compound a value of (2.99 ± 0.12) × 10−12 cm3 molecule−1 s−1 at a temperature of 298 K was obtained for the rate constant. The products (and product yields) for the OH reaction with MTBE in the presence of NOx were also determined and found to be t‐butyl formate (0.68 ± 0.05), methyl acetate (0.14 ± 0.02), acetone (0.026 ± 0.003), t‐butanol (0.062 ± 0.009), and formaldehyde (0.48 ± 0.05) in mols/mol MTBE converted. The OH rate constant for the major product formed, t‐butyl formate was also measured and found to be (7.37 ± 0.05) × 10−13 cm3 molecule−1 s−1. Mechanisms to rationalize the formation of the products are presented.

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BackgroundAdvocates for environmental justice, local, state, and national public health officials, exposure scientists, need broad-based health indices to identify vulnerable communities. Longitudinal studies show that perception of current health status predicts subsequent mortality, suggesting that self-reported health (SRH) may be useful in screening-level community assessments. This paper evaluates whether SRH is an appropriate surrogate indicator of health status by evaluating relationships between SRH and sociodemographic, lifestyle, and health care factors as well as serological indicators of nutrition, health risk, and environmental exposures.MethodsData were combined from the 2003–2006 National Health and Nutrition Examination Surveys for 1372 nonsmoking 20–50 year olds. Ordinal and binary logistic regression was used to estimate odds ratios and 95 % confidence intervals of reporting poorer health based on measures of nutrition, health condition, environmental contaminants, and sociodemographic, health care, and lifestyle factors.ResultsPoorer SRH was associated with several serological measures of nutrition, health condition, and biomarkers of toluene, cadmium, lead, and mercury exposure. Race/ethnicity, income, education, access to health care, food security, exercise, poor mental and physical health, prescription drug use, and multiple health outcome measures (e.g., diabetes, thyroid problems, asthma) were also associated with poorer SRH.ConclusionBased on the many significant associations between SRH and serological assays of health risk, sociodemographic measures, health care access and utilization, and lifestyle factors, SRH appears to be a useful health indicator with potential relevance for screening level community-based health and environmental studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3321-5) contains supplementary material, which is available to authorized users.

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Urinary arsenic (As) concentrations were evaluated as a biomarker of exposure in a U.S. population chronically exposed to inorganic As (InAs) in their ddnking water. Ninety-si individuals who consumed drinking water with As concentrations of 8-620 P/L provided first moring urine voids for up to 5 consecutive days. The study population was 56% male, and 44% was younger than 18 year of age. On one day of the study period, all voided urines were collected over a 24-hr period. Arsenic intake from drnking water was estimated from daily food diaries.Comparison between the concentration of As in individual urine voids with that in the 24-hr urine collection indicated that the. ncentration of As in urine was sble throughout the day.Comparison of the concentration ofAs in each first morning urine void over the 5-day studyod indicated that there was little day-to-day variation in the co on of.As in urine. The concentration of As in drinking water was a better predictor of the concenton of As in urine than was the estimated intake of from driking water. little information on intra-or interindividual variation in the output of As in urine independent of dose. In particular, there is little information on the extent of As exposure in U.S. populations that consume drinking water that contains As. The research described in this paper provides novel information on the pattern and extent of urinary As excretion in a U.S. population exposed to As in drinking water.In the present study, we evaluated the excretion of As in urine in a Millard County, Utah, population that is chronically exposed to InAs from drinking water. We found that the concentration ofAs excreted in urine was highly correlated with the concentration of InAs in the drinking water supply and the concentration of As in urine was remarkably stable throughout a single day and over a 5-day study period. These findings suggest that the analysis of a small number of urine samples may be adequate to estimate an individual's exposure to InAs from drinking water and that the determination of the concentration of InAs in a drinking water supply may be a useful surrogate for estimating exposure to this metalloid. MethodsSite selection. Study subjects were recruited from long-term residents of Millard County, Utah. The primary industry in this region is agricultural, and surface water is only used for crop irrigation. Drinking water supplies are obtained from public and private wells. The source of the InAs in drinking water is As that occurs naturally in the soil and rock strata. The likely sources of soil As are several extinct volcanos within the study area. The state of Utah has measured InAs concentrations in the wells used for drinking water and livestock in this area for more than 30 years.The InAs concentrations of wells in this area have been stable for many years and range from 2 to over 600 pg/L (16).Subject selection. The study population included mostly members of the Church of Jesus Christ of Latter-Day Saints. Possible confounding factors such as smoking, alco...

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