BackgroundDetection of estrogens in the environment has raised concerns in recent years because of their potential to affect both wildlife and humans.ObjectivesWe compared exposures to prescribed and naturally occurring estrogens in drinking water to exposures to naturally occurring background levels of estrogens in the diet of children and adults and to four independently derived acceptable daily intakes (ADIs) to determine whether drinking water intakes are larger or smaller than dietary intake or ADIs.MethodsWe used the Pharmaceutical Assessment and Transport Evaluation (PhATE) model to predict concentrations of estrogens potentially present in drinking water. Predicted drinking water concentrations were combined with default water intake rates to estimate drinking water exposures. Predicted drinking water intakes were compared to dietary intakes and also to ADIs. We present comparisons for individual estrogens as well as combined estrogens.ResultsIn the analysis we estimated that a child’s exposures to individual prescribed estrogens in drinking water are 730–480,000 times lower (depending upon estrogen type) than exposure to background levels of naturally occurring estrogens in milk. A child’s exposure to total estrogens in drinking water (prescribed and naturally occurring) is about 150 times lower than exposure from milk. Adult margins of exposure (MOEs) based on total dietary exposure are about 2 times smaller than those for children. Margins of safety (MOSs) for an adult’s exposure to total prescribed estrogens in drinking water vary from about 135 to > 17,000, depending on ADI. MOSs for exposure to total estrogens in drinking water are about 2 times lower than MOSs for prescribed estrogens. Depending on the ADI that is used, MOSs for young children range from 28 to 5,120 for total estrogens (including both prescribed and naturally occurring sources) in drinking water.ConclusionsThe consistently large MOEs and MOSs strongly suggest that prescribed and total estrogens that may potentially be present in drinking water in the United States are not causing adverse effects in U.S. residents, including sensitive subpopulations.

In an effort to assess the combined risk estrone (E1), 17β-estradiol (E2), 17α-ethinyl estradiol (EE2), and estriol (E3) pose to aquatic wildlife across United States watersheds, two sets of predicted-no-effect concentrations (PNECs) for significant reproductive effects in fish were compared to predicted environmental concentrations (PECs). One set of PNECs was developed for evaluation of effects following long-term exposures. A second set was derived for short-term exposures. Both sets of PNECs are expressed as a 17β-estradiol equivalent (E2-eq), with 2 and 5 ng/L being considered the most likely levels above which fish reproduction may be harmed following long-term and short-term exposures, respectively. A geographic information system-based water quality model, Pharmaceutical Assessment and Transport Evaluation (PhATE™), was used to compare these PNECs to mean and low flow concentrations of the steroid estrogens across 12 U.S. watersheds. These watersheds represent approximately 19% of the surface area of the 48 North American states, contain 40 million people, and include over 44,000 kilometers of rivers. This analysis determined that only 0.8% of the segments (less than 1.1% of kilometers) of these watersheds would have a mean flow E2-eq concentration exceeding the long-term PNEC of 2.0 ng/L; only 0.5% of the segments (less than 0.8% of kilometers) would have a critical low flow E2-eq exceeding the short-term PNEC of 5 ng/L. Those few river segments where the PNECs were exceeded were effluent dominated, being either headwater streams with a publicly owned treatment works (POTW), or flowing through a highly urbanized environment with one or several POTWs. These results suggest that aquatic species in most U.S. surface waters are not at risk from steroid estrogens that may be present as a result of human releases.

The long‐term fish consumption rate (also referred to as the “usual fish consumption rate” [UFCR]) is a critical assumption in the derivation of human health remedial goals for contaminated sediments. At many sites, remedial goals are established using fish consumption rates based on information available from surveys of the general population or of specific highly exposed populations. To be protective of human health, remedial goals are often established using those high‐end fish consumption rates. However, high‐end fish consumption rates may overestimate the amount of fish that can be sustainably harvested and consumed and, thus, lead to remedial goals that may not be representative of long‐term consumption from the contaminated portion of a water body. This paper presents a methodology to estimate the amount of edible fish that can be harvested sustainably from a contaminated sediment site. The methodology requires 1) estimating the total fish productivity of the area of contaminated sediments, 2) estimating the portion of total productivity that can be harvested sustainably, and 3) determining the portion of the sustainable harvest that is edible fish tissue. Estimates of total fish production rate (TFPR) and the proportion of such harvest that can be harvested sustainably rely primarily on available compilations of TFPR and harvest measurements across a range of water bodies throughout the world. Estimates of the fraction of whole fresh fish that is consumed rely on information available from the United States Environmental Protection Agency (USEPA). The methodology is used to develop sustainable UFCRs for 4 hypothetical water bodies with distinct characteristics and to compare the UFCRs to commonly used default fish consumption rates. Estimates of sustainable production provide risk managers valuable perspective about the benefits realized by cleanup of contaminated sediment sites. Integr Environ Assess Manag 2021;17:584–596. © 2020 SETAC

This article presents the capability expansion of the PhATE™ (pharmaceutical assessment and transport evaluation) model to predict concentrations of trace organics in sludges and biosolids from municipal wastewater treatment plants (WWTPs). PhATE was originally developed as an empirical model to estimate potential concentrations of active pharmaceutical ingredients (APIs) in US surface and drinking waters that could result from patient use of medicines. However, many compounds, including pharmaceuticals, are not completely transformed in WWTPs and remain in biosolids that may be applied to land as a soil amendment. This practice leads to concerns about potential exposures of people who may come into contact with amended soils and also about potential effects to plants and animals living in or contacting such soils. The model estimates the mass of API in WWTP influent based on the population served, the API per capita use, and the potential loss of the compound associated with human use (e.g., metabolism). The mass of API on the treated biosolids is then estimated based on partitioning to primary and secondary solids, potential loss due to biodegradation in secondary treatment (e.g., activated sludge), and potential loss during sludge treatment (e.g., aerobic digestion, anaerobic digestion, composting). Simulations using 2 surrogate compounds show that predicted environmental concentrations (PECs) generated by PhATE are in very good agreement with measured concentrations, i.e., well within 1 order of magnitude. Model simulations were then carried out for 18 APIs representing a broad range of chemical and use characteristics. These simulations yielded 4 categories of results: 1) PECs are in good agreement with measured data for 9 compounds with high analytical detection frequencies, 2) PECs are greater than measured data for 3 compounds with high analytical detection frequencies, possibly as a result of as yet unidentified depletion mechanisms, 3) PECs are less than analytical reporting limits for 5 compounds with low analytical detection frequencies, and 4) the PEC is greater than the analytical method reporting limit for 1 compound with a low analytical detection frequency, possibly again as a result of insufficient depletion data. Overall, these results demonstrate that PhATE has the potential to be a very useful tool in the evaluation of APIs in biosolids. Possible applications include: prioritizing APIs for assessment even in the absence of analytical methods; evaluating sludge processing scenarios to explore potential mitigation approaches; using in risk assessments; and developing realistic nationwide concentrations, because PECs can be represented as a cumulative probability distribution. Finally, comparison of PECs to measured concentrations can also be used to identify the need for fate studies of compounds of interest in biosolids.

A probabilistic risk assessment (PRA) using a range of sustainable usual fish consumption rates (SUFCRs) was performed to evaluate the potential health risks from consuming resident fish at two contaminated sediment sites. The analysis focused on the Portland Harbor Superfund Site, a large river in Oregon, and Koppers Pond, a small pond in New York. At both sites, the sediment cleanup remedy is driven by PCBs in resident fish. The PRA fit probability distributions to inputs used to develop a distribution of SUFCR, the long-term fish consumption rate sustainably supported by a fishery, and other exposure parameters to calculate the range and likelihood of cancer risks and noncancer hazards for adult anglers. At the 95th percentile, which is often considered a reasonable maximum exposure (RME), the SUFCRs calculated using site-specific inputs are six-to ten-fold lower than the point estimate fish consumption rates used in the deterministic baseline human health risk assessment conducted for each site. The combination of sustainable fish consumption rates and probabilistic methods results in a range of risks and thereby provides more information than the more commonly used deterministic approach. For over 99% of the resident fish-consuming population, the potential cancer risks and noncancer hazards calculated in the PRA are below the deterministic estimates for the RME adult consumer at each site. The combination of PRA with the estimation of SUFCRs is a novel application of these techniques at contaminated sediment sites that provides critical information for risk management decision-making.