Over 6 billion pounds per year of the estrogenic monomer bisphenol A (BPA) are used to manufacture polycarbonate plastic products, in resins lining metal cans, in dental sealants, and in blends with other types of plastic products. The ester bond linking BPA molecules in polycarbonate and resins undergoes hydrolysis, resulting in the release of free BPA into food, beverages, and the environment, and numerous monitoring studies now show almost ubiquitous human exposure to biologically active levels of this chemical. BPA exerts estrogenic effects through the classical nuclear estrogen receptors, and BPA acts as a selective estrogen receptor modulator. However, BPA also initiates rapid responses via estrogen receptors presumably associated with the plasma membrane. Similar to estradiol, BPA causes changes in some cell functions at concentrations between 1 pM and 1 nM, and the mean and median range of unconjugated BPA measured by multiple techniques in human pregnant maternal, fetal, and adult blood and other tissues exceeds these levels. In contrast to these published findings, BPA manufacturers persist in describing BPA as a weak estrogen and insist there is little concern with human exposure levels. Our concern with human exposure to BPA derives from 1) identification of molecular mechanisms mediating effects in human and animal tissues at very low doses, 2) in vivo effects in experimental animals caused by low doses within the range of human exposure, and 3) widespread human exposure to levels of BPA that cause adverse effects in animals.

/pdf/large-effects-from-small-exposures-iii-endocrine-mechanisms-3k58mpzcdf.pdf

Large Effects from Small Exposures. III. Endocrine Mechanisms Mediating Effects of Bisphenol A at Levels of Human Exposure

Molecular diagnostic ratios (MDRs)—the ratios of defined pairs of individual compounds—have been widely used as markers of different source categories of polycyclic aromatic hydrocarbons (PAHs). However, it is well-known that variations in combustion conditions and environmental degradation processes can cause substantial variability in the emission and degradation of individual compounds, potentially undermining the application of MDRs as reliable source apportionment tools. The United Kingdom produces a national inventory of atmospheric emissions of PAHs, and has an ambient air monitoring program at a range of rural, semirural, urban, and industrial sites. The inventory and the monitoring data are available over the past 20 years (1990–2010), a time frame that has seen known changes in combustion type and source. Here we assess 5 MDRs that have been used in the literature as source markers. We examine the spatial and temporal variability in the ratios and consider whether they are responsive to known di...

PAH molecular diagnostic ratios applied to atmospheric sources: a critical evaluation using two decades of source inventory and air concentration data from the UK.

A study of trace metals and polycyclic aromatic hydrocarbons in the roadside environment

The characteristics of carbonaceous species and their sources in PM2.5 in Beijing

Concentration and chemical characteristics of PM2.5 in Beijing, China: 2001–2002

Characterization of atmospheric trace elements on PM2.5 particulate matter over the New York-New Jersey harbor estuary

Polycyclic aromatic hydrocarbons (PAHs, n = 36) were measured in the gas and particle phases in the atmosphere and the dissolved and particle phases in the waters of the New York—New Jersey Harbor Estuary, USA, during a weeklong intensive field campaign in July 1998. Mean total (gas + particulate) phenanthrene and pyrene concentrations were 3.3 and 0.33 ng/m3, respectively, over Raritan Bay, and 14 and 1.1 ng/m3, respectively, over New York Harbor. Similar PAH profiles (p values < 0.01) in the atmospheric gas phase and the dissolved phase in water demonstrate the close coupling of the air and water compartments. Air—water exchange fluxes of PAHs estimated using shore-based air data lead to erroneous flux estimates when compared to those derived using over-water air samples. The gross absorptive air—water flux dominates atmospheric loadings (wet, dry particle, gas absorption) to the estuary for PAHs of molecular weight < 234 g/mol. Dry particle deposition is increasingly more important for the higher-molecular-weight, particle-bound PAH species. Gross volatilization dominates gross absorption for the majority of PAHs in the New York—New Jersey Harbor Estuary.

Air-water exchange of polycyclic aromatic hydrocarbons in the New York-New Jersey, USA, Harbor Estuary.

Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured at urban/industrial, suburban, coastal, and rural areas in New Jersey as part of the New Jersey Atmospheric Deposition Network. Concentrations of 36 PAH compounds were measured in the gas and particle phases in air and in precipitation at nine sites at regular intervals from October 1997 through May 2001. Gas-phase and particle-phase s36PAH concentrations ranged from 0.45 to 118 ng m-3 and from 0.046 to 172 ng m-3, respectively, and precipitation concentrations ranged from 11 to 16200 ng L-1. PAH concentrations vary spatially across the region, with the highest concentrations occurring at the most heavily urban and industrial locations. Average gas absorption deposition ranged from 0.004 (naphthacene) to 5040 (methylphenanthrenes) ng m-2 d-1, and dry particle deposition PAH fluxes ranged from 0.11 (naphthacene) to 300 (benzo[b+k]fluoranthene) ng m-2 d-1 at the nine sites. Average atmospheric wet deposition PAH fluxes at the seven sites ranged from 0.40 (cyclopenta-[cd]pyrene) to 140 (methylphenanthrenes) ng m-2 d-1. These represent the first comprehensive estimates of PAH deposition to New Jersey and the Mid-Atlantic East Coast. (A)

Atmospheric concentrations and deposition of polycyclic aromatic hydrocarbons to the Mid-Atlantic East Coast region.

Processes driving the short-term variability of polycyclic aromatic hydrocarbons in the Baltimore and northern Chesapeake Bay atmosphere, USA

Spatial and temporal trends of polychlorinated biphenyl (PCB) concentrations in precipitation were measured at urban and background sites as part of the New Jersey Atmospheric Deposition Network (NJADN). The volume weighted mean concentration (VWM) of ΣPCBs (sum of PCBs) based on precipitation measurements at three background sites was in the range of 0.30−0.50 ng/L. Concentrations in precipitation at two urban-industrial sites were on average 7−43 times higher than background concentrations. Wet deposition fluxes of ΣPCBs at the two urbanized sites were 16 ± 3.4 and 3.9 ± 0.72 μg/m2-yr, while the background flux was approximately 0.30 μg/m2-yr. On average, 97% of the total atmospheric washout (WT) of PCBs resulted from particle scavenging. The fraction of atmospheric PCBs on particles was the best predictor of atmospheric washout in both urban (log WT = 0.71 (±0.049) log φ + 4.9 (±0.11); r2 = 0.81) and nonurban areas (log WT = 0.77 (±0.083) log φ + 5.6 (±0.16); r2 = 0.64). Wet deposition fluxes of ΣPCBs ...

Thomas R. Glenn

Papers

Characterization of atmospheric trace elements on PM2.5 particulate matter over the New York-New Jersey harbor estuary

Air-water exchange of polycyclic aromatic hydrocarbons in the New York-New Jersey, USA, Harbor Estuary.

Atmospheric concentrations and deposition of polycyclic aromatic hydrocarbons to the Mid-Atlantic East Coast region.

Processes driving the short-term variability of polycyclic aromatic hydrocarbons in the Baltimore and northern Chesapeake Bay atmosphere, USA

Wet deposition of polychlorinated biphenyls in urban and background areas of the Mid-Atlantic States.