Homing pigeons externally exposed to Deepwater Horizon crude oil change flight performance and behavior.

The Deepwater Horizon oil spill was the largest in U.S. history, contaminating thousands of miles of coastal habitat and affecting the lives of many avian species. The Gulf of Mexico is a critical bird migration route area and migrants that were oiled but did not suffer mortality as a direct result of the spill faced unpredictable fates. This study utilized homing pigeons as a surrogate species for migratory birds to investigate the effects a single low level external oiling event has on the flight performance and behavior of birds flying repeated 161 km flights. Data from GPS data loggers showed that lightly oiled pigeons changed their flight paths, increased their flight durations by 2.6 fold, increased their flight distances by 28 km and subsequently decreased their route efficiencies. Oiled birds also exhibited reduced rate of weight gain between flights. Our data suggest that contaminated birds surviving the oil spill may have experienced flight impairment and reduced refueling abilities, likely reducing overall migration speed. Our findings contribute new information on how oil spills affect avian species, as the effects of oil on the flight behavior of long distance free-flying birds have not been previously described.

Low level exposure to crude oil impacts avian flight performance: The Deepwater Horizon oil spill effect on migratory birds.

In 2010, the Deepwater Horizon oil spill released 134 million gallons of crude oil into the Gulf of Mexico making it the largest oil spill in US history. The three month oil spill left tens of thousands of birds dead; however, the fate of tens of thousands of other migratory birds that were affected but did not immediately die is unknown. We used the homing pigeon as a surrogate species for migratory birds to investigate the effects of a single external oiling event on the flight performance of birds. Data from GPS data loggers revealed that lightly oiled pigeons took significantly longer to return home and spent more time stopped en route than unoiled birds. This suggests that migratory birds affected by the oil spill could have experienced long term flight impairment and delayed arrival to breeding, wintering, or crucial stopover sites and subsequently suffered reductions in survival and reproductive success.

Body mass change in flying homing pigeons externally exposed to Deepwater Horizon crude oil.

The Deepwater Horizon oil spill contaminated thousands of miles of habitat valuable to hundreds of species of migratory and resident birds of the Gulf of Mexico. Many birds died as a direct result of the oil spill; however, the indirect effects of oil exposure on the flight ability and body condition of birds are difficult to assess in situ. This study utilizes the homing pigeon as a surrogate species for migratory birds to investigate the effect of multiple external oil exposures on the flight performance and body mass change of birds over a series of repeated flights from 136.8km flight distance. Oiled pigeons took significantly longer to return home, lost more weight during flight, and were unable to recover their weight, resulting in reduction of body weight overtime. Based on our data, migratory birds that were oiled, even partially, by the Deepwater Horizon oil spill likely took longer to complete migration and were likely in poor body condition, increasing their risk of mortality and reproductive failure.

Thyroid antagonists and thyroid indicators in U.S. pregnant women in the Vanguard Study of the National Children's Study.

The sodium iodide-symporter (NIS) mediates uptake of iodide into thyroid follicular cells. This key step in thyroid hormone synthesis is inhibited by perchlorate, thiocyanate (SCN) and nitrate (NO3) anions. When these exposures occur during pregnancy the resulting decreases in thyroid hormones may adversely affect neurodevelopment of the human fetus. Our objectives were to describe and examine the relationship of these anions to the serum thyroid indicators, thyroid stimulating hormone (TSH) and free thyroxine (FT4), in third trimester women from the initial Vanguard Study of the National Children's Study (NCS); and to compare urine perchlorate results with those in pregnant women from the National Health and Nutritional Examination Survey (NHANES). Urinary perchlorate, SCN, NO3, and iodine, serum TSH, FT4, and cotinine were measured and a food frequency questionnaire (FFQ) was administered to pregnant women enrolled in the initial Vanguard Study. We used multiple regression models of FT4 and TSH that included perchlorate equivalent concentration (PEC, which estimates combined inhibitory effects of the anions perchlorate, SCN, and NO3 on the NIS). We used multiple regression to model predictors of each urinary anion, using FFQ results, drinking water source, season of year, smoking status, and demographic characteristics. Descriptive statistics were calculated for pregnant women in NHANES 2001-2012. The geometric mean (GM) for urinary perchlorate was 4.04µg/L, for TSH 1.46mIU/L, and the arithmetic mean for FT4 1.11ng/dL in 359 NCS women. In 330 women with completed FFQs, consumption of leafy greens, winter season, and Hispanic ethnicity were significant predictors of higher urinary perchlorate, which differed significantly by study site and primary drinking water source, and bottled water was associated with higher urinary perchlorate compared to filtered tap water. Leafy greens consumption was associated with higher urinary NO3 and higher urinary SCN. There was no association between urinary perchlorate or PEC and TSH or FT4, even for women with urinary iodine <100µg/L. GM urinary perchlorate concentrations in the full sample (n=494) of third trimester NCS women (4.03µg/L) were similar to pregnant women in NHANES (3.58µg/L).

Assessment of Exposure to VOCs among Pregnant Women in the National Children's Study.

Epidemiologic studies can measure exposure to volatile organic compounds (VOCs) using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children's Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS) method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS). We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking) and by observations by a trained data collector (presence of scented products in homes). We found several significant (p < 0.01) relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite N-acetyl-S-(benzyl)-L-cysteine (BMA), and paint use was positively associated with the xylene metabolites 2-methylhippuric acid (2MHA) and 3-Methylhippuric acid & 4-methylhippuric acid (3MHA + 4MHA). A near-significant (p = 0.06) relationship was observed between acrylamide metabolites and observation of incense.

Prenatal mercury concentration is associated with changes in DNA methylation at TCEANC2 in newborns.

BACKGROUND: Human exposure to the widespread environmental contaminant mercury is a known risk factor for common diseases such as cancer, cardiovascular disease and neurological disorders through poorly characterized mechanisms. Evidence suggests mercury exposure may alter DNA methylation levels, but to date, the effects in early life on a genome-wide scale have not been investigated. METHODS: A study sample of 141 newborns was recruited in Baltimore, MD, USA and total mercury and methylmercury were measured in cord blood samples. We quantified genome-wide DNA methylation data using CHARM 2.0, an array-based method, and used region-finding analyses to identify concentration-associated differentially methylated regions (DMRs). To test for replication of these identified DMRs in the pilot, or Vanguard, phase of the National Children's Study (NCS), we compared bisulfite-pyrosequenced DNA at candidate regions from 85 whole cord blood samples with matched first trimester maternal mercury concentration measures. RESULTS: Total mercury concentration was associated with methylation at DMRs inside ANGPT2 and near PRPF18 genes [false discovery rate (FDR) < 0.05], as well as DMRs near FOXD2 and within TCEANC2 (FDR< 0.1) genes. Methylmercury concentration was associated with an overlapping DMR within TCEANC2 (FDR< 0.05). In NCS replication analyses, methylation levels at three of four cytosine-guanine DNA dinucleotides (CpG sites) within the TCEANC2 DMR were associated with total mercury concentration (P < 0.05), and this association was diminished after adjusting for estimated cell proportions. CONCLUSIONS: Evidence for an association between mercury and DNA methylation at the TCEANC2 region was found, which may represent a mercury-associated shift in cord blood cell composition or a change in methylation within blood cell types. Further confirmatory studies are needed.