Background: The U.S. Environmental Protection Agency (U.S. EPA) has estimated the neurological benefits of reductions in prenatal methylmercury (MeHg) exposure in past assessments of rules ...controlling mercury (Hg) emissions. A growing body of evidence suggests that MeHg exposure can also lead to increased risks of adverse cardiovascular impacts in exposed populations. Data extraction: The U.S. EPA assembled the authors of this article to participate in a workshop, where we reviewed the current science concerning cardiovascular health effects of MeHg exposure via fish and seafood consumption and provided recommendations concerning whether cardiovascular health effects should be included in future Hg regulatory impact analyses. Data synthesis: We found the body of evidence exploring the link between MeHg and acute myocardial infarction (MI) to be sufficiently strong to support its inclusion in future benefits analyses, based both on direct epidemiological evidence of an MeHg—MI link and on MeHg's association with intermediary impacts that contribute to MI risk. Although additional research in this area would be beneficial to further clarify key characteristics of this relationship and the biological mechanisms that underlie it, we consider the current epidemiological literature sufficiently robust to support the development of a dose-response function. Conclusions: We recommend the development of a dose-response function relating MeHg exposures with MIs for use in regulatory benefits analyses of future rules targeting Hg air emissions.
The extent to which breastfeeding is protective against later-life obesity is controversial. Little is known about differences in infant body composition between breastfed and formula-fed infants, ...which may reflect future obesity risk.
We aimed to assess associations of infant feeding with trajectories of growth and body composition from birth to 7 mo in healthy infants.
We studied 276 participants from a previous study of maternal vitamin D supplementation during lactation. Mothers used monthly feeding diaries to report the extent of breastfeeding. We measured infants’ anthropometrics and used dual-energy X-ray absorptiometry to assess body composition at 1, 4, and 7 mo. We compared changes in infant size (z scores for weight, length, and body mass index BMI (in kg/m2)) and body composition (fat and lean mass, body fat percentage) between predominantly breastfed and formula-fed infants, adjusting in linear regression for sex, gestational age, race/ethnicity, maternal BMI, study site, and socioeconomic status.
In this study, 214 infants (78%) were predominantly breastfed (median duration: 7 mo) and 62 were exclusively formula fed. Formula-fed infants had lower birth-weight z scores than breastfed infants (−0.22 ± 0.86 and 0.16 ± 0.88, respectively; P < 0.01) but gained more in weight and BMI through 7 mo of age (weight z score difference: 0.37; 95% CI: 0.04, 0.71; BMI z score difference: 0.35; 95% CI: 0, 0.69), with no difference in linear growth (z score difference: 0.05; 95% CI: −0.24, 0.34). Formula-fed infants gained more lean mass (difference: 303 g; 95% CI: 137, 469 g) than breastfed infants, but not fat mass (difference: −42 g; 95% CI: −299, 215 g).
Formula-fed infants gained weight more rapidly and out of proportion to linear growth than did predominantly breastfed infants. These differences were attributable to greater accretion of lean mass, rather than fat mass. Any later obesity risk associated with infant feeding does not appear to be explained by differential adiposity gains in infancy.
In this paper, we present findings from a multiyear expert judgment study that comprehensively characterizes uncertainty in estimates of mortality reductions associated with decreases in fine ...particulate matter (PM2.5) in the U.S. Appropriate characterization of uncertainty is critical because mortality-related benefits represent up to 90% of the monetized benefits reported in the Environmental Protection Agency’s (EPA’s) analyses of proposed air regulations. Numerous epidemiological and toxicological studies have evaluated the PM2.5−mortality association and investigated issues that may contribute to uncertainty in the concentration−response (C−R) function, such as exposure misclassification and potential confounding from other pollutant exposures. EPA’s current uncertainty analysis methods rely largely on standard errors in published studies. However, no one study can capture the full suite of issues that arise in quantifying the C−R relationship. Therefore, EPA has applied state-of-the-art expert judgment elicitation techniques to develop probabilistic uncertainty distributions that reflect the broader array of uncertainties in the C−R relationship. These distributions, elicited from 12 of the world’s leading experts on this issue, suggest both potentially larger central estimates of mortality reductions for decreases in long-term PM2.5 exposure in the U.S. and a wider distribution of uncertainty than currently employed in EPA analyses.
To assess the validity of body mass index (BMI) and age- and sex-standardized BMI z-score (BMIZ) as surrogates for adiposity (body fat percentage BF%, fat mass, and fat mass index kg/m2) at 3 time ...points in infancy (1, 4, and 7 months) and to assess the extent to which the change in BMIZ represents change in adiposity.
We performed a secondary analysis of 447 full-term infants in a previous trial of maternal vitamin D supplementation during lactation. Study staff measured infant anthropometrics and assessed body composition with dual-energy x-ray absorptiometry at 1, 4, and 7 months of age. We calculated Spearman correlations (rs) among BMI, BMIZ, and adiposity at each time point, and between change in BMIZ and change in adiposity between time points.
Infants (N = 447) were 52% male, 38% white, 31% black, and 29% Hispanic. The BMIZ was moderately correlated with BF% (rs = 0.43, 0.55, 0.48 at 1, 4, and 7 months of age, respectively). BMIZ correlated more strongly with fat mass and fat mass index, particularly at 4 and 7 months of age (fat mass rs = 0.72-0.76; fat mass index rs = 0.75-0.79). Changes in BMIZ were moderately correlated with adiposity changes from 1 to 4 months of age (rs = 0.44 with BF% change; rs = 0.53 with fat mass change), but only weakly correlated from 4 to 7 months of age (rs = 0.21 with BF% change; rs = 0.27 with fat mass change).
BMIZ is moderately correlated with adiposity in infancy. Changes in BMIZ are a poor indicator of adiposity changes in later infancy. BMI and BMIZ are limited as surrogates for adiposity and especially adiposity changes in infancy.
ClinicalTrials.gov: NCT00412074.
The U.S. Environmental Protection Agency undertook a case study in the Detroit metropolitan area to test the viability of a new multipollutant risk‐based (MP/RB) approach to air quality management, ...informed by spatially resolved air quality, population, and baseline health data. The case study demonstrated that the MP/RB approach approximately doubled the human health benefits achieved by the traditional approach while increasing cost less than 20%—moving closer to the objective of Executive Order 12866 to maximize net benefits. Less well understood is how the distribution of health benefits from the MP/RB and traditional strategies affect the existing inequalities in air‐pollution‐related risks in Detroit. In this article, we identify Detroit populations that may be both most susceptible to air pollution health impacts (based on local‐scale baseline health data) and most vulnerable to air pollution (based on fine‐scale PM2.5 air quality modeling and socioeconomic characteristics). Using these susceptible/vulnerable subpopulation profiles, we assess the relative impacts of each control strategy on risk inequality, applying the Atkinson Index (AI) to quantify health risk inequality at baseline and with either risk management approach. We find that the MP/RB approach delivers greater air quality improvements among these subpopulations while also generating substantial benefits among lower‐risk populations. Applying the AI, we confirm that the MP/RB strategy yields less PM2.5 mortality and asthma hospitalization risk inequality than the traditional approach. We demonstrate the value of this approach to policymakers as they develop cost‐effective air quality management plans that maximize risk reduction while minimizing health inequality.
Formally evaluating how specific policy measures influence environmental justice is challenging, especially in the context of regulatory analyses in which quantitative comparisons are the norm. ...However, there is a large literature on developing and applying quantitative measures of health inequality in other settings, and these measures may be applicable to environmental regulatory analyses. In this paper, we provide information to assist policy decision makers in determining the viability of using measures of health inequality in the context of environmental regulatory analyses. We conclude that quantification of the distribution of inequalities in health outcomes across social groups of concern, considering both within-group and between-group comparisons, would be consistent with both the structure of regulatory analysis and the core definition of environmental justice. Appropriate application of inequality indicators requires thorough characterization of the baseline distribution of exposures and risks, leveraging data generally available within regulatory analyses. Multiple inequality indicators may be applicable to regulatory analyses, and the choice among indicators should be based on explicit value judgments regarding the dimensions of environmental justice of greatest interest.
The formation and fallout of oil-related marine snow have been associated with interactions between dispersed oil and small marine particles, like phytoplankton and mineral particles. In these ...studies, the influences of phytoplankton species, mineral particle concentration, and oil concentration on the aggregation of oil in seawater (SW) were investigated. The experiments were performed in a low-turbidity carousel incubation system, using natural SW at 13 °C. Aggregation was measured by silhouette camera analyses, and oil compound group distribution and depletion by gas chromatography (GC-FID or GC–MS). Aggregates with median sizes larger than 500 μm in diameter were measured in the presence of dispersed oil and the phytoplankton species Thalassiosira rotula, Phaeocystis globosa, Skeletonema pseudocostatum, but not with the microalgae Micromonas pusilla. When mineral particles (diatomaceous earth) were incubated at different concentrations (5–30 mg/L) with dispersed oil and S. pseudocostatum, the largest aggregates were measured at the lower mineral particle concentration (5 mg/L). Since dispersed oil rapidly dilutes in the marine water column, experiments were performed with oil concentrations of from 10 mg/L to 0.01 mg/L in the presence of S. pseudocostatum and diatomaceous earth. Aggregates larger than 500 μm was measured only at the highest oil concentrations (10 mg/L). However, oil attachment to the marine particles were also measured at low oil concentrations (≤1 mg/L). Depletion of oil compound groups (n-alkanes, naphthalenes, PAHs, decalins) were measured at all oil concentrations, both in aggregate and water phases, with biodegradation as the expected main depletion process. These results showed that oil concentration may be important for oil-related marine snow formation, but that even oil droplets at low concentrations may attach to the particles and be transported by prevailing currents.
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•Oil-related aggregates were formed with phytoplankton, mineral particles and dispersed oil.•Aggregate formations and sizes varied between phytoplankton species.•Particle sizes were increased by low, but reduced by high mineral particle concentrations.•Aggregation required dispersed oil concentrations of 1 mg/L or more.•Oil compound groups sorbed to marine particles also at low oil concentrations.
Exposure to fine particulate matter (PM
2.5
) is associated with asthma development as well as asthma exacerbation in children. PM
2.5
can be directly emitted or can form in the atmosphere from ...pollutant precursors. PM
2.5
emitted and formed in the atmosphere is influenced by meteorology; future changes in climate may alter the concentration and distribution of PM
2.5
. Our aim is to estimate the future burden of climate change and PM
2.5
on new and exacerbated cases of childhood asthma. Projected concentrations of PM
2.5
are based on the Geophysical Fluid Dynamics Laboratory Coupled Model version 3 climate model, the Representative Concentration Pathway 8.5 greenhouse gas scenario, and two air pollution emissions datasets: a 2011 emissions dataset and a 2040 emissions dataset that reflects substantial reductions in emissions of PM
2.5
as compared to the 2011 inventory. We estimate additional PM
2.5
-attributable asthma as well as PM
2.5
-attributable albuterol inhaler use for four future years (2030, 2050, 2075, and 2095) relative to the year 2000. Exacerbations, regardless of the trigger, are counted as attributable to PM
2.5
if the incident disease is attributable to PM
2.5
. We project 38 thousand (95% CI 36, 39 thousand) additional PM
2.5
-attributable incident childhood asthma cases and 29 million (95% CI 27, 31 million) additional PM
2.5
-attributable albuterol inhaler uses per year in 2030, increasing to 200 thousand (95% CI 190, 210 thousand) additional incident cases and 160 million (95% CI 150, 160 million) inhaler uses per year by 2095 relative to 2000 under the 2011 emissions dataset. These additional PM
2.5
-attributable incident asthma cases and albuterol inhaler use would cost billions of additional U.S. dollars per year by the late century. These outcomes could be mitigated by reducing air pollution emissions.
In this study, the formation and fate of oil-related aggregates (ORAs) from chemically dispersed oil in seawater (SW) were investigated at different temperatures (5 °C, 13 °C, 20 °C). Experiments in ...natural SW alone, and in SW amended with typical marine snow constituents (phytoplankton and mineral particles), showed that the presence of algae stimulated the formation of large ORAs, while high SW temperature resulted in faster aggregate formation. The ORAs formed at 5 °C and 13 °C required mineral particles for sinking, while the aggregates also sank in the absence of mineral particles at 20°. Early in the experimental periods, oil compound accumulation in ORAs was faster than biodegradation, particularly in aggregates with algae, followed by rapid biodegradation. High abundances of bacteria associated with hydrocarbon biodegradation were determined in the ORAs, together with algae-associated bacteria, while clustering analyses showed separation between bacterial communities in experiments with oil alone and oil with algae/mineral particles.
•Oil-related marine snow was generated from chemically dispersed oil.•Formation of aggregates was faster in seawater at high than at low temperatures.•Aggregate sizes were larger in the presence than the absence of algae.•Sinking oil-related aggregates were only observed at high seawater temperature.•Oil compound groups were biodegraded in the aggregates.•High abundances of oil-degrading bacteria were associated with the aggregates.
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