Survival, Growth, and Reproduction Responses in a Three-Generation Exposure of the Zebrafish (Danio rerio) to Perfluorooctane Sulfonate.

A prior multigenerational perfluorooctane sulfonic acid (PFOS) exposure investigation in zebrafish reported adverse effects at 0.734 µg/L, among the lowest aquatic effect levels for PFOS reported to date. The present three-generation PFOS exposure quantified survival, growth, reproduction, and vitellogenin (VTG; egg yolk protein) responses in zebrafish, incorporating experimental design and procedural improvements relative to the earlier study. Exposures targeting 0.1, 0.6, 3.2, 20, and 100 µg/L in parental (P) and first filial (F1) generations lasted for 180 days post fertilization (dpf) and the second filial generation (F2) through 16 dpf. Survival decreased significantly in P and F2 generation exposures, but not in F1, at the highest PFOS treatment (100 µg/L nominal, 94-205 µg/L, measured). Significant adverse effects on body weight and length were infrequent, of low magnitude, and occurred predominantly at the highest exposure treatment. Finally, PFOS had no significant effects on P or F1 egg production and survival or whole-body VTG levels in P or F1 male fish. Overall, the predominance and magnitude of adverse PFOS effects at <1 µg/L reported in prior research were largely nonrepeatable in the present study. In contrast, the present study indicated a threshold for ecologically relevant adverse effects in zebrafish at 117 µg/L (SE 8 µg/L, n = 10) for survival and 47 µg/L (SE 11 µg/L, n = 19) for all statistically significant negative effects observed. Environ Toxicol Chem 2024;43:115-131. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Frameworks for screening and risk management of chemicals and advanced materials: A critical review.

Despite the evolution over the last half century of regulatory programs and frameworks developed for the evaluation of safety and management of risks associated with chemicals and materials, new and emerging contaminant issues continue to be identified. These recurring issues suggest a need for review and reflection on current approaches and strategies for ensuring the safety of chemicals and materials. Twelve existing frameworks relating to the evaluation and management of chemical or material risk were reviewed to identify potential process improvements for facilitating early identification of potentially problematic substances and better inform risk management strategies (e.g., prohibition, restricted use, or selection of safer alternatives). The frameworks were selected to represent a broad spectrum of regional, national, and international authorities and purposes, including preproduction evaluation of new substances, classification and hazard communication, identification of persistent pollutants, and identification of safer alternatives. Elements common to the frameworks were identified, as well as features unique to select frameworks. A comparative evaluation was performed, and potential new strategies and approaches were identified to inform process improvement recommendations. These recommendations include requiring validated analytical procedures to enable measurement in environmental media, improved data transparency and accessibility, flexibility to incorporate advances into the state of the practice (e.g., new approach methodologies and high-throughput assessment tools), and incorporation of monitoring and adaptive management strategies to enable more timely intervention. Process improvement recommendations are discussed and summarized in a conceptual risk management framework. Integr Environ Assess Manag 2023;19:1192-1206. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Chronic aquatic toxicity of perfluorooctane sulfonic acid (PFOS) to Ceriodaphnia dubia, Chironomus dilutus, Danio rerio, and Hyalella azteca.

Perfluorooctane sulfonic acid (PFOS) is a ubiquitous and persistent contaminant in aquatic ecosystems. Chronic toxicity information for aquatic organisms is limited, therefore we conducted chronic PFOS toxicity tests for four model organisms commonly used for freshwater toxicology assays: Chironomus dilutus (midge), Ceriodaphnia dubia (water flea), Hyalella azteca (amphipod) and Danio rerio (zebrafish). The 16-day survival test with C. dilutus resulted in the lowest PFOS exposure concentrations to cause significant impacts, with reduced survival at 1 µg/L, a LC50 of 7.5 µg/L, and a growth EC10 of 1.5 µg/L. D. rerio was the next most sensitive species, with a 30-day LC50 of 490 µg/L and reduced growth at 260 µg/L. Effects for C. dubia and H. azteca occurred at concentrations a thousand-fold higher than for C. dilutus. H. azteca had a 42-day LC50 of 15 mg/L, an EC50 of 3.8 mg/L for reproduction (neonates per female) and an EC50 of 4.7 mg/L for growth. C. dubia was similarly tolerant of PFOS, with a 6-day LC50 of 20 mg/L for survival and an EC50 of 7 mg/L for reproduction (neonates per adult). H. azteca, C. dubia, and, to a lesser extent, D. rerio, appear tolerant of PFOS concentrations typically found in the environment. However, in agreement with previous studies, C. dilutus was particularly sensitive to PFOS exposure, with lethal and sublethal effects occurring at concentration levels present at highly contaminated sites.

Acute Toxicity of Eight Aqueous Film-Forming Foams to 14 Aquatic Species.

Researchers have developed numerous per- and polyfluoroalkyl substances (PFAS)-free aqueous film-forming foam (AFFF) formulations to replace PFAS-containing AFFF used for fire suppression. As part of the Department of Defense's Strategic Environmental Research and Development Program (SERDP), we examined the direct lethal effects of seven PFAS-free AFFF and a PFAS-containing AFFF on 14 aquatic species using a series of lethal concentration (LC50) tests. We assessed the LC10, LC50, and LC90 values using log-logistic and logit analyses. Across all aquatic species tested, we discovered that exposure to at least one PFAS-free AFFF was more or as toxic as exposure to the PFAS-containing AFFF. For most cases, National Foam Avio F3 Green KHC 3% and Buckeye Platinum Plus C6MILSPEC 3% were the most and least toxic formulations, respectively. Moreover, we found consistency among results from multiple experiments using the same minnow species (Pimephales promelas) and among closely related taxa (e.g., daphnids, amphibians). Lastly, the LC50 values for AFFF formulations trended lower for tested marine species as compared to those of freshwater species. These results dramatically increase the current knowledge on the potentially toxic effects of AFFF but also highlight the need for additional research and the development of new PFAS-free AFFF that are more "ecologically friendly" than those containing persistent PFAS.

Interlaboratory Comparison of Three Sediment Bioaccumulation Tests.

Standard bioaccumulation tests are commonly conducted using Macoma nasuta (clam), and Alitta virens (polychaete) for marine tests, and Lumbriculus variegatus (an oligochaete) for freshwater tests. Because the interlaboratory variability associated with these tests is unknown, four experienced laboratories conducted standard 28-day bioaccumulation tests with the above species using sediments contaminated with polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). Chemical analysis of tissue samples was performed by a single laboratory. The intralaboratory variance among replicates was relatively low for PCB tissue concentrations, with coefficients of variation (CVs) ranging from 9% to 28% for all laboratories and species, with the exception of one laboratory reporting higher variability for L. variegatus (CV = 51%). Intralaboratory variance for PCB tissue concentrations was higher than interlaboratory variance for A. virens and L. variegatus, and the magnitude of difference (MOD) for laboratory means ranged from 1.4 to 2.0 across species. Intralaboratory variability was also low for lipid content, and lipid normalization of PCB and PAH body residues generally had little impact on variability. In addition to variability across bioassay laboratories, analytical variability was evaluated by different laboratories measuring the concentration of PCBs and total lipids in a subsample of tissue homogenate of sediment-exposed test organisms. Variability associated with tissue analysis was higher than bioassay laboratory variability only in tests with L. variegatus. Statistical differences between samples may be observed due to the low intralaboratory variability; however, the biological significance of these differences may be limited because the MOD is low. Considering the MOD when comparing bioaccumulation across treatments accounts for uncertainty related to inherent variability of the test in the interpretation of statistically significant results. Environ Toxicol Chem 2022;41:1260-1275. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Passive-Sampler-Based Bioavailability Assessment of PCB Congeners Associated with Aroclor-Containing Paint Chips in the Presence of Sediment.

This is the first investigation of the bioavailability of PCBs associated with paint chips (PC) dispersed in sediment. Bioavailability of PCB-containing PC in sediment was measured using ex situ polyethylene passive samplers (PS) and compared to that of PCBs from field-collected sediments. PC were mixed in freshwater sediment from a relatively uncontaminated site with no known PCB contamination sources and from a contaminated site with non-paint PCB sources. PC < 0.045 mm generated concentrations in the PS over one order of magnitude higher than coarser chips. The bioavailable fraction was represented by the polymer-sediment accumulation factor (PSAF), defined as the ratio of the PCB concentrations in the PS and organic carbon normalized sediment. The PSAF was similar for both field sediments. The PSAFs for the field sediments were ~ 50-60 and ~ 5 times higher than for the relatively uncontaminated sediment amended with PC for the size fractions 0.25-0.3 mm and < 0.045 mm, respectively. These results indicate much lower bioavailability for PCBs associated with PC compared to PCBs associated with field-collected sediment. Such information is essential for risk assessment and remediation decision-making for sites where contamination from non-paint PCBs sources is co-located with PCB PC.

Streamlining Freshwater Bioaccumulation Bioassays: Letting the Worms Do the Hard Work.

When terminating sediment bioaccumulation tests with the oligochaete Lumbriculus variegatus, varying amounts of detrital material are retained along with the recovered worms after sieving, necessitating time-consuming, labor-intensive manual separation of worms from detritus prior to tissue residue analysis. A method to facilitate the worms self-extracting out of the detrital material into a column of gravel was developed, resulting in approximately 90% recovery test organisms (on a mass basis) at test termination. Following exposure to contaminated sediment, polychlorinated biphenyl tissue residues and residual sediment in the gut of self-extracted animals were not significantly different compared to worms recovered by manual separation followed by purging of gut contents. Environ Toxicol Chem 2021;40:1673-1677. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.

Perfluorooctanesulfonic Acid-Induced Toxicity on Zebrafish Embryos in the Presence or Absence of the Chorion.

Perfluorooctanesulfonic acid (PFOS) is a perfluorinated compound used in many industrial and consumer products. It has been linked to a broad range of adverse effects in several species, including zebrafish (Danio rerio). The zebrafish embryo is a widely used vertebrate model to elucidate potential adverse effects of chemicals because it is amenable to medium and high throughput. However, there is limited research on the full extent of the impact the chorion has on those effects. Results from the present study indicate that the presence of the chorion affected the timing and incidence of mortality as well as morphometric endpoints such as spinal curvature and swim bladder inflation in zebrafish embryos exposed to PFOS. Furthermore, removal of the chorion prior to exposure resulted in a lower threshold of sensitivity to PFOS for effects on transcriptional expression within the peroxisome proliferator-activated receptor (PPAR) nuclear signaling pathway. Perturbation of PPAR pathway gene expression can result in disruption of metabolic signaling and regulation, which can adversely affect development, energy availability, and survival. It can be concluded that removal of the chorion has significant effects on the timing and incidence of impacts associated with PFOS exposure, and more research is warranted to fully elucidate the protective role of the chorion and the critical timing of these events. Environ Toxicol Chem 2021;40:780-791. Published 2020. This article is a US Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Evaluation of dredged sediment for aquatic placement: interpreting contaminant bioaccumulation.

The potential bioaccumulation of sediment-associated contaminants is one of the primary concerns associated with the aquatic placement of dredged sediment. Laboratory bioaccumulation tests with representative infaunal organisms exposed to dredged sediment and reference sediment are used to assess the potential for contaminant-related bioaccumulation impacts. Dredged sediment testing and evaluation guidance provides statistical inferences and numerous assessment factors (e.g., the magnitude of difference (MOD)) to interpret results; however, detailed information for applying these factors is lacking. Therefore, the focus of this work was to provide context for the application of the MOD as a line of evidence for evaluating bioaccumulation risk associated with dredged material placement in aquatic environments by considering variance (as coefficient of variation (CV)), MOD, and statistical differences associated with bioaccumulation bioassay tissue concentrations in three case studies. Based on peer-reviewed data and dredged material monitoring data, relatively low within-sample variability (CVs < 50%) of tissue concentrations can be achieved for commonly assessed constituents (e.g., polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), metals, and butyl tins). Thus, statistical comparisons were generally able to detect significant differences (p < 0.05; α = 0.05) across tissue concentrations with relatively low MODs (< 2-fold difference). Based on the observed variance, MOD, and statistical differences associated with bioaccumulation bioassay tissue concentrations, a 2-fold MOD can provide an additional line of evidence to evaluate bioaccumulative risk when statistical significance is observed. These results indicated that a judicious consideration of the sample variance and MOD is a useful factor when discerning meaningful differences among contaminant tissue concentrations.

Comparison of Acute and Chronic Toxicity Laboratory Bioassay Endpoints with Benthic Community Responses in Field-Exposed Contaminated Sediments.

Sediment toxicity is usually assessed by conducting laboratory bioassays on thoroughly homogenized, field-collected, sediment samples. Although it is generally held that these bioassays provide a conservative assessment of the potential for environmental impact, there are few studies comparing the results of laboratory sediment bioassays with actual measures of benthic community health in exposed field populations. To help inform an understanding of the relative efficacy of laboratory-based bioassays in predicting potential impacts in exposed field populations, a laboratory-to-field comparison study was conducted. Laboratory bioassays included standard 10-d acute toxicity tests measuring survival in 4 species of estuarine/marine amphipods (Eohaustorius estuarius, Ampelisca abdita, Rhepoxinius abronius, and Leptocheirus plumulosus) and 2 longer term, 28-d sublethal tests with a marine polychaete, Neanthes arenaceodentata (survival and growth), and the amphipod L. plumulosus (survival, growth, and reproduction). A highly contaminated and toxic sediment was mixed with a cleaner sediment of similar grain size to produce a series of diluted contaminated sediment treatments (0, 6, 12, 25, and 50%). Sediment treatments were placed in containers and deployed in the field. At specified intervals (at time of deployment and 9 and 12 mo post deployment), containers were retrieved from the field and analyzed for sediment chemistry, infaunal community composition, and toxicity. Laboratory toxicity endpoints were compared with measures of benthic community health to evaluate the ability of the toxicity tests to accurately predict benthic impacts. The results of these comparisons indicate that the laboratory tests evaluated provide conservative estimates of potential benthic community impacts, with both acute and chronic tests detecting effects at lower treatment levels than were detected in exposed field populations using traditional measures of benthic community health. Environ Toxicol Chem 2019;38:1784-1802. Published 2019 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work, and as such, is in the public domain in the United States of America.

Application of ecosystem services in natural resource management decision making.

An ecosystem services (ES) approach to natural resource management (NRM) can provide the framework for balancing economic, ecological, and societal drivers in decision making. The efficacy of such an approach depends on the successful execution of several key activities, from early and continuous engagement with relevant stakeholders, to development and application of ecological production functions (EPFs), to explicit recognition of uncertainty in the process. Although there are obstacles to the implementation of an ES approach in NRM, including unclear regulatory and policy frameworks and the paucity of useful EPFs, many of the tools are currently available or sufficiently developed. An ES approach can and, in some cases, should involve qualitative rather than quantitative assessment when the stakes are not very high or when quantitative approaches would not be cost effective because of highly uncertain results. Integr Environ Assess Manag 2017;13:74-84. © 2016 SETAC.

Tracking Public Beliefs About Anthropogenic Climate Change.

A simple question about climate change, with one choice designed to match consensus statements by scientists, was asked on 35 US nationwide, single-state or regional surveys from 2010 to 2015. Analysis of these data (over 28,000 interviews) yields robust and exceptionally well replicated findings on public beliefs about anthropogenic climate change, including regional variations, change over time, demographic bases, and the interacting effects of respondent education and political views. We find that more than half of the US public accepts the scientific consensus that climate change is happening now, caused mainly by human activities. A sizable, politically opposite minority (about 30 to 40%) concede the fact of climate change, but believe it has mainly natural causes. Few (about 10 to 15%) say they believe climate is not changing, or express no opinion. The overall proportions appear relatively stable nationwide, but exhibit place-to-place variations. Detailed analysis of 21 consecutive surveys within one fairly representative state (New Hampshire) finds a mild but statistically significant rise in agreement with the scientific consensus over 2010-2015. Effects from daily temperature are detectable but minor. Hurricane Sandy, which brushed New Hampshire but caused no disaster there, shows no lasting impact on that state's time series-suggesting that non-immediate weather disasters have limited effects. In all datasets political orientation dominates among individual-level predictors of climate beliefs, moderating the otherwise positive effects from education. Acceptance of anthropogenic climate change rises with education among Democrats and Independents, but not so among Republicans. The continuing series of surveys provides a baseline for tracking how future scientific, political, socioeconomic or climate developments impact public acceptance of the scientific consensus.

A field test and comparison of acute and chronic sediment toxicity tests with the estuarine amphipod Leptocheirus plumulosus in Chesapeake Bay, USA.

A 28-d partial life-cycle test with the estuarine amphipod Leptocheirus plumulosus was developed in response to the need for an assay to mimic chronic exposure to sediment-associated contaminants. To ensure that toxicity tests have environmental relevance, it is essential to evaluate the relationship between laboratory responses and field measures of contamination. Consequently, one objective of the study was to compare the results of the chronic sediment toxicity test with L. plumulosus to gradients of sediment contamination and the in situ benthic community in its native Chesapeake Bay. Chronic tests were conducted by two laboratories, the Army Corps of Engineers Waterways Experiment Station ([WES]; Vicksburg, MS, USA) and the University of Maryland ([UM] College Park, MD, USA) using different feeding regimes, providing the opportunity to evaluate the effect of this variable on response sensitivity. A second objective was to compare the relative sensitivity of acute and chronic tests with L. plumulosus with field-collected sediments. Overall, there was good agreement between the toxicological response of acute and chronic tests with L. plumulosus and field measures of contamination. Survival in the acute test and chronic test conducted by WES was negatively correlated with concentrations of sediment-associated contaminants. Survival in acute exposures was significantly reduced in sediments from 8 of 11 stations. Indigenous L. plumulosus were found only at two of the three stations that did not exhibit acute toxicity. An unexpected finding was the difference in responsiveness of the two chronic tests. Survival in tests conducted by UM and WES was significantly reduced in sediments from 4 and 6 of 11 stations, respectively. No additional sublethal toxicity was detected in the UM chronic test, but the WES test detected reproductive effects at two additional stations. We believe the observed differences were related to the test diet used. Partly as a result of our findings, the recommended diet for the L. plumulosus chronic test was changed in the final methods document.