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Environmental research [journal]
- Trends in blood mercury concentrations and fish consumption among U.S. women of reproductive age, NHANES, 1999-2010. [JOURNAL ARTICLE]
- Environ Res 2014 Mar 3.
Consumption of finfish and shellfish is the primary exposure pathway of methylmercury (MeHg) in the US. MeHg exposure in utero is associated with neurodevelopmental and motor function deficits. Regulations and fish advisories may contribute to decreased exposure to mercury over time.Combine fish tissue mercury (FTHg) concentrations and 1999-2010 NHANES blood mercury concentrations and fish consumption data to investigate trends in blood mercury concentrations, fish consumption, and mercury intake in women of reproductive age.Blood MeHg was calculated from the blood total and inorganic concentrations. Dietary datasets were combined to estimate 30-day fish consumption, then combined with FTHg concentrations to estimate mercury intake and mercury concentration in the fish consumed. Non-linear and logistic regression analyses were used to evaluate trends over time.Regression analysis found NHANES 1999-2000 to have higher blood MeHg concentrations than the mean of the later releases (p<0.0001) and a positive quadratic trend since 2000 (p=0.004). No trend was observed in fish consumption amount or mercury intake. A decreasing trend was found in the ratio of mercury intake to fish consumed (p=0.04).The analyses found blood MeHg concentrations in NHANES 1999-2000 to be significantly higher than the mean of the later releases. There was no trend in fish consumption amount across the study period. The analysis found a decreasing trend in the ratio of mercury intake to fish consumed, consistent with women shifting their consumption to fish with lower mercury concentrations.
- The environmental roots of non-communicable diseases (NCDs) and the epigenetic impacts of globalization. [JOURNAL ARTICLE]
- Environ Res 2014 Mar 1.
Non-communicable diseases (NCDs) are increasing worldwide. We hypothesize that environmental factors (including social adversity, diet, lack of physical activity and pollution) can become "embedded" in the biology of humans. We also hypothesize that the "embedding" partly occurs because of epigenetic changes, i.e., durable changes in gene expression patterns. Our concern is that once such factors have a foundation in human biology, they can affect human health (including NCDs) over a long period of time and across generations.To analyze how worldwide changes in movements of goods, persons and lifestyles (globalization) may affect the "epigenetic landscape" of populations and through this have an impact on NCDs. We provide examples of such changes and effects by discussing the potential epigenetic impact of socio-economic status, migration, and diet, as well as the impact of environmental factors influencing trends in age at puberty.The study of durable changes in epigenetic patterns has the potential to influence policy and practice; for example, by enabling stratification of populations into those who could particularly benefit from early interventions to prevent NCDs, or by demonstrating mechanisms through which environmental factors influence disease risk, thus providing compelling evidence for policy makers, companies and the civil society at large. The current debate on the '25×25 strategy', a goal of 25% reduction in relative mortality from NCDs by 2025, makes the proposed approach even more timely.Epigenetic modifications related to globalization may crucially contribute to explain current and future patterns of NCDs, and thus deserve attention from environmental researchers, public health experts, policy makers, and concerned citizens.
- Leukemia, lymphoma and multiple myeloma mortality (1950-1999) and incidence (1969-1999) in the Eldorado uranium workers cohort. [Journal Article]
- Environ Res 2014 Apr.:43-50.
Uranium workers are chronically exposed to low levels of radon decay products (RDP) and gamma (γ) radiation. Risks of leukemia from acute and high doses of γ-radiation are well-characterized, but risks from lower doses and dose-rates and from RDP exposures are controversial. Few studies have evaluated risks of other hematologic cancers in uranium workers. The purpose of this study was to analyze radiation-related risks of hematologic cancers in the cohort of Eldorado uranium miners and processors first employed in 1932-1980 in relation to cumulative RDP exposures and γ-ray doses. The average cumulative RDP exposure was 100.2 working level months and the average cumulative whole-body γ-radiation dose was 52.2 millisievert. We identified 101 deaths and 160 cases of hematologic cancers in the cohort. Overall, male workers had lower mortality and cancer incidence rates for all outcomes compared with the general Canadian male population, a likely healthy worker effect. No statistically significant association between RDP exposure or γ-ray doses, or a combination of both, and mortality or incidence of any hematologic cancer was found. We observed consistent but non-statistically significant increases in risks of chronic lymphocytic leukemia (CLL) and Hodgkin lymphoma (HL) incidence and non-Hodgkin lymphoma (NHL) mortality with increasing γ-ray doses. These findings are consistent with recent studies of increased risks of CLL and NHL incidence after γ-radiation exposure. Further research is necessary to understand risks of other hematologic cancers from low-dose exposures to γ-radiation.
- Post-Vietnam military herbicide exposures in UC-123 Agent Orange spray aircraft. [Journal Article]
- Environ Res 2014 Apr.:34-42.
During the Vietnam War, approximately 20 million gallons of herbicides, including ~10.5 million gallons of dioxin-contaminated Agent Orange, were sprayed by about 34 UC-123 aircraft that were subsequently returned to the United States, without decontamination or testing, to three Air Force reserve units for transport operations (~1971-1982). In 1996, observed dioxin contamination led to withdrawal of these UC-123s from public auction and to their smelting in 2009. Current Air Force and Department of Veterans Affairs policies stipulate that "dried residues" of chemical herbicides and dioxin had not lead to meaningful exposures to flight crew and maintenance personnel, who are thus ineligible for Agent Orange-related benefits or medical examinations and treatment. Sparse monitoring data are available for analysis.Three complementary approaches for modeling potential exposures to dioxin in the post-Vietnam war aircraft were employed: (1) using 1994 and 2009 Air Force surface wipe data to model personnel exposures and to estimate dioxin body burden for dermal-oral exposure for dried residues using modified generic US Environmental Protection Agency intake algorithms; (2) comparing 1979 Air Force 2,4- dichlorophenoxyacetic acid and 2,4-5-trichlorophenoxyacetic acid air samples to saturated vapor pressure concentrations to estimate potential dioxin exposure through inhalation, ingestion and skin contact with contaminated air and dust; and (3) applying emission models for semivolatile organic compounds from contaminated surfaces to estimate airborne contamination.Model (1): Body-burden estimates for dermal-oral exposure were 0.92 and 5.4pg/kg body-weight-day for flight crew and maintainers. The surface wipe concentrations were nearly two orders of magnitude greater than the US Army guidance level. Model (2): measured airborne concentrations were at least five times greater than saturated vapor pressure, yielding dioxin estimates that ranged from 13.2-27.0pg/m(3), thus supporting the likelihood of dioxin dust adsorption. Model (3): Theoretical models yielded consistent estimates to Model 2, 11-49pg/m(3), where the range reflects differences in experimental value of dioxin vapor pressure and surface area used. Model (3) results also support airborne contamination and dioxin dust adsorption.Inhalation, ingestion and skin absorption in aircrew and maintainers were likely to have occurred during post-Vietnam use of the aircraft based on the use of three complementary models. Measured and modeled values for dioxin exceeded several available guidelines. Deposition-aerosolization-redeposition homeostasis of semivolatile organic compound contaminants, particularly dioxin, is likely to have continually existed within the aircraft. Current Air Force and Department of Veterans Affairs policies are not consistent with the available industrial hygiene measurements or with the widely accepted models for semivolatile organic compounds.
- Maternal exposure to biomass smoke and carbon monoxide in relation to adverse pregnancy outcome in two high altitude cities of Peru. [Journal Article]
- Environ Res 2014 Apr.:29-33.
Exposure to pollution from biomass fuel has been associated with low birthweight in some studies. Few studies have included exposure-response analyses.We conducted a case-control study of biomass fuel use and reproductive outcome at high altitude in Peru. Cases (n=101) were full term births who were SGA (birth weight <10th percentile for gestational age). Controls (n=101) had a birthweight ≥10th percentile, and were matched to cases on birth week and residence. Biomass fuel use during pregnancy was determined by questionnaire. Carbon monoxide (CO) in the kitchen was measured in a subgroup (n=72). Logistic regression was used to estimate the effects of biofuel and CO on the risk of SGA, controlling for maternal education and parity.Among cases, 30%, 27% and 44% used gas, gas+biomass, and biomass, respectively, while the figures for controls were 39%, 33%, and 29%. The adjusted odds ratio (OR) for biomass fuel alone compared with gas alone was 4.5 (95% CI: 1.3, 15.5, p=0.02), while the OR for biomass+gas vs. gas alone was 2.1 (0.80-5.5) (p=0.13). Among the subgroup with measured CO, the mean 48-h kitchen CO levels were 4.8, 2.2 and 0.4ppm for biofuel only, biofuel+gas, and gas respectively. ORs by increasing tertile of CO level were 1.0, 1.16, and 3.53 (test for trend, p=0.02). The exposure-response trend corresponds well with one other study with analogous data.Despite limited sample size, our data suggest that maternal exposure to biomass smoke and CO, at high altitude, is associated with SGA among term births.
- Comparison of the accuracy of kriging and IDW interpolations in estimating groundwater arsenic concentrations in Texas. [Journal Article]
- Environ Res 2014 Apr.:59-69.
Exposure to arsenic causes many diseases. Most Americans in rural areas use groundwater for drinking, which may contain arsenic above the currently allowable level, 10µg/L. It is cost-effective to estimate groundwater arsenic levels based on data from wells with known arsenic concentrations. We compared the accuracy of several commonly used interpolation methods in estimating arsenic concentrations in >8000 wells in Texas by the leave-one-out-cross-validation technique. Correlation coefficient between measured and estimated arsenic levels was greater with inverse distance weighted (IDW) than kriging Gaussian, kriging spherical or cokriging interpolations when analyzing data from wells in the entire Texas (p<0.0001). Correlation coefficient was significantly lower with cokriging than any other methods (p<0.006) for wells in Texas, east Texas or the Edwards aquifer. Correlation coefficient was significantly greater for wells in southwestern Texas Panhandle than in east Texas, and was higher for wells in Ogallala aquifer than in Edwards aquifer (p<0.0001) regardless of interpolation methods. In regression analysis, the best models are when well depth and/or elevation were entered into the model as covariates regardless of area/aquifer or interpolation methods, and models with IDW are better than kriging in any area/aquifer. In conclusion, the accuracy in estimating groundwater arsenic level depends on both interpolation methods and wells' geographic distributions and characteristics in Texas. Taking well depth and elevation into regression analysis as covariates significantly increases the accuracy in estimating groundwater arsenic level in Texas with IDW in particular.
- Lead exposure and rate of change in cognitive function in older women. [Journal Article]
- Environ Res 2014 Feb.:69-75.
Higher long-term cumulative lead exposure predicts faster cognitive decline in older men, but evidence of an association in women is lacking.To determine if there is an association between lead exposure and cognitive decline in women.This study considers a sample of 584 women from the Nurses' Health Study who live in or near Boston, Massachusetts. We quantified lead exposure using biomarkers of lead exposure assessed in 1993-2004 and evaluated cognitive decline by repeated performance on a telephone battery of cognitive tests primarily assessing learning, memory, executive function, and attention completed in 1995-2008. All cognitive test scores were z-transformed for use in analyses. We used linear mixed models with random effects to quantify the association between each lead biomarker and change in cognition overall and on each individual test.Consideration of individual tests showed greater cognitive decline with increased tibia lead concentrations, a measure of long-term cumulative exposure, for story memory and category fluency. The estimated excess annual decline in overall cognitive test z-score per SD increase in tibia bone lead concentration was suggestive, although the confidence intervals included the null (0.024 standard units, 95% confidence interval: -0.053, 0.004 - an additional decline in function equivalent to being 0.33 years older). We found little support for associations between cognitive decline and patella or blood lead, which provide integrated measures of exposure over shorter timeframes.Long-term cumulative lead exposure may be weakly associated with faster cognitive decline in community-dwelling women, at least in some cognitive domains.
- Effects of heavy metals on biomarkers for oxidative stress in Griffon vulture (Gyps fulvus). [Journal Article]
- Environ Res 2014 Feb.:59-68.
Metals are involved in the formation of reactive oxygen species (ROS) which may result in metal-related oxidative stress that can lead to oxidative damage to lipids, DNA and proteins. It is necessary to understand the mechanisms of metal toxicity in wild birds, and the concentrations that cause effects on oxidative stress biomarkers. The aim of this study is to assess the concentrations of lead (Pb), cadmium (Cd), mercury (Hg), copper (Cu) and zinc (Zn) with regards to oxidative stress in blood samples of 66 Griffon vultures (Gyps fulvus) from two areas of the Autonomous Community of Valencia (East of Spain). The two study areas (Alcoy n=36 and Cinctorres n=30) were selected as random locations of interest that had not yet been studied, and are feeding stations where supplementary food, mainly of pork origin, is provided for vultures. Given that the two study areas are not considered polluted sites, we expected to find low metal concentrations. However, there are no known threshold concentrations at which metals can affect antioxidant systems, and low metal levels may have an effect on antioxidant biomolecules. In this study, since sampling was done at the beginning of the hunting season, the low Pb levels found in most Griffon vultures from Alcoy and Cinctorres (median=12.37 and 16.26μg/dl, respectively) are suggestive of background levels usually found in vultures that feed on pork carcasses all year round. The ingestion of game meat with bullet fragments in carcasses or with Pb shots embedded in the flesh could be the cause of the high blood Pb concentrations found in three vultures from Cinctorres (83, 290 and 362μg/dl). Griffon vultures feeding in Cinctorres had enhanced CAT and GST activities and tGSH concentrations, which may be interpreted as protective response against the higher TBARS levels. This study provides threshold concentrations at which metals affect antioxidant system derived from 66 samples of Griffon vulture. Blood Cd concentrations greater than 0.05μg/dl produced an induction of 33% in GPx and of 44% in CAT activity in erythrocytes of vultures from Alcoy. Hg concentrations in blood higher than 3μg/dl produced an induction of 10% in SOD activity. Concentrations of Pb above 15µg/dl in blood produced an inhibition of 12.5% in GPx and 11.3% in CAT activity, and a TBARS induction of 10.7% in erythrocytes of Griffon vultures.
- Thoracic bioelectrical impedance assessment of the hemodynamic reactions to recorded road-traffic noise in young adults. [Journal Article]
- Environ Res 2014 Feb.:52-8.
Noise exposure increases blood pressure in both experimental and field studies. The underlying mechanisms may be evaluated by thoracic bioelectrical impedance. The aim of this experimental study was to assess changes in blood pressure, cardiac and hemodynamic parameters provoked by recorded traffic noise in young adults. The study included 130 participants (42 men and 88 women), aged 24.88±2.67 years. Thoracic electrical bioimpedance device was applied to monitor cardiac parameters, hemodynamic parameters, heart rate variability, blood pressure and heart rate. The testing procedure consisted of three phases. Participants were exposed to recorded road-traffic noise (Leq=89dBA) for 10min and relaxed in quiet conditions (Leq=40dBA) before and after noise exposure. Listening to recorded noise resulted in significant decrease of stroke volume and cardiac output, and an increase of vascular resistance. Heart rate variability and the overall sympathovagal balance remained similar through all experimental conditions. During noise exposure, systolic pressure increased by 2mmHg among women (95% confidence interval=0.97-2.73mmHg), and by 4mmHg among men (95% confidence interval=2.16-5.00mmHg). Similarly, diastolic pressure increased by 2mmHg among women (95% confidence interval=0.95-2.47mmHg), and by 4mmHg among men (95% confidence interval=2.46-5.28mmHg). Once noise ceased, both pressures returned to pre-exposure levels. Experimental exposure to recorded road-traffic noise of 89dBA for 10min provoked significant hemodynamic changes in young adults, including vasoconstriction (increase of vascular resistance), and hypodynamics (decrease of global heart flow). The interaction of these effects resulted in the elevation of blood pressure during noise exposure.
- The association between prenatal exposure to organochlorine pesticides and thyroid hormone levels in newborns in Yancheng, China. [Journal Article]
- Environ Res 2014 Feb.:47-51.
Organochlorine pesticides can interfere with the thyroid hormones that play an important role in early neurodevelopment. Although organochlorine pesticides have been banned in China since 1983, their residues are still detectable in the environment. However, few studies have investigated the adverse health effects of prenatal exposure to organochlorine pesticide residues on newborns in China. The present study, conducted in Yancheng City, Jiangsu Province, China, aimed to examine the association between the levels of organochlorine pesticides in maternal and cord sera and to assess the impact of prenatal exposure to organochlorine pesticides on thyroid hormone levels in cord serum. Eleven organochlorine pesticides in maternal and cord sera were measured in 247 mother-infant pairs recruited from Yancheng City between February 2010 and June 2010. The concentration of the thyroid hormones free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin (TSH) were determined in cord serum. Among the 11 tested organochlorine pesticides, the detectable levels of hexachlorobenzene (HCB), β-hexachlorocycolohexane (β-HCH) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) in both maternal and cord sera were above 50%. The levels of β-HCH and p,p'-DDE in maternal sera were positively associated with the levels in cord sera (r=0.421, P<0.01; r=0.288, P<0.01). After adjusting for confounders, the TSH level in cord serum samples was negatively associated with the HCB level (OR=0.535, 95% CI=(0.304-0.941)). Our data demonstrated that DDT, β-HCH and HCB residues bioconcentrate in maternal and cord sera. Moreover, the correlation analysis suggested that organochlorine pesticides in maternal blood can transfer through the placenta and affect newborn thyroid hormone levels.