Geology topics

Jeffery A. Steevens

Publications and source records attributed to Jeffery A. Steevens.

At least 19 recordsLinked to original sources

USGS2026

Acute toxicity and tissue concentrations of 6PPD-quinone in Arctic grayling (Thymallus arcticus, Thymallinae)

Studies of N -(1,3-dimethylbutyl)- N' -phenyl- p -phenylenediamine-quinone (6PPDQ) toxicity have identified sensitive and resistant species within the subfamily Salmoninae, but thus far fewer than 10 species, all in two genera ( Oncorhynchus and Salvelinus ), have shown sensitivity in experiments. The Arctic grayling ( Thymallus arcticus , Salmonidae, Thymallinae) was extirpated from its range in the Great Lakes region of the United States, but because of the importance of this species to the Native American tribes of Michigan, a reintroduction effort is underway. Because high 6PPDQ concentrations have been found in Great Lakes tributaries, it is important to understand if this species is at risk from 6PPDQ exposure. Using standard methods with flow-through exposures to provide stable 6PPDQ concentrations, we exposed Arctic grayling at 3 weeks after swim-up to a series of 6PPDQ concentrations for 96 hr, evaluating mortality and measuring tissue concentrations of 6PPDQ in surviving and dying fish. We observed that grayling were sensitive to 6PPDQ, with 24- and 96-hr median lethal concentrations of 5,136 and 3,137 ng/L, respectively. Tissue concentrations were much higher than those observed in other sensitive salmonines in previous studies. While this is only the third genus found to be sensitive to 6PPDQ leading to acute lethality and the first species outside of Salmoninae, the median lethal concentrations determined for the Arctic grayling exposed in this study are at 6PPDQ water concentrations unlikely to be encountered in situ.

Great Lakes↗

USGS2026

Time course of effects and tissue concentrations of 6PPDQ in three sensitive salmonids with additional data for two centrarchid species

Studies of 6PPD-quinone (6PPDQ) toxicity have identified both sensitive and resistant salmonid species at environmentally relevant concentrations. However, comparisons between species are complicated by varying testing conditions, which can limit the application to derivation of environmental quality guidelines. Furthermore, few studies have reported 6PPDQ tissue concentrations in fish with known exposure concentrations. Using standard methods with flow-through exposures to provide stable 6PPDQ concentrations, we compared time courses of mortality in three sensitive salmonid species (coho salmon Oncorhynchus kisutch , brook trout Salvelinus fontinalis , rainbow trout Oncorhynchus mykiss ), evaluated the potential for latent (delayed) mortality, and measured tissue concentrations in both fish that died during exposure and those that survived an additional 7 days in clean water. Further experiments documented insensitivity in two centrarchids (smallmouth bass Micropterus dolomieu and largemouth bass Micropterus nigricans ). Our study provided evidence for two mortality time courses: one in which nearly all mortality occurs in the first 24 h and one in which mortalities continue to accumulate throughout the exposure, and 96-h and 24-h LC50s are quite different. We did not observe evidence for the delayed onset of mortality due to 6PPDQ exposure. Most fish that survived exposure had undetectable 6PPDQ concentrations after 1 week in clean water, potentially informing biomonitoring strategies for wild populations.

Environmental Science & Technology↗

USGS2025

Are behavioural ecotoxicity endpoints relevant at the population level? Evidence-based insights for environmental protection

A substantial body of evidence exists demonstrating that exposure to environmental contaminants can alter animal behavior. Moreover, methodological and technological advancements, as well as increasing standardization, mean that behavioral ecotoxicity studies are more rigorous and reliable than ever before. Despite this, behavioral data are still seldom used in the risk assessment and regulation of chemicals. This is partly due to a lack of clarity among some stakeholders about whether changes in behavior at the individual level result in population-level outcomes. To address this, we first consider the state of evidence within the field of behavioral ecotoxicology linking individual-level behavioral alterations with population-level consequences. We then assess the evidence from behavioral ecology and other neighboring fields that supports this link. Further, we evaluate whether some behavioral endpoints are more easily tied to population-level changes than others. In this regard, we propose combining insights from two complementary ecological frameworks─the functional trait framework and the limiting traits framework─to evaluate which behaviors should be prioritized in ecotoxicological research and regulatory efforts. We contend that the link between behavioral changes and population-level outcomes is evident, with behavioral endpoints representing a highly valuable yet so far underutilized line of evidence in applied environmental protection.

Environmental Science and Technology↗

USGS2025

Influence of activated carbon on the bioaccumulation of methylmercury from sediment by the amphipod Leptocheirus plumulosus

We evaluated the potential for activated carbon (AC) amendments to reduce the bioavailability of methylmercury (MeHg) in field-collected sediments. To do so, we adapted a standard 28-day bioaccumulation bioassay with the benthic invertebrate Leptocheirus plumulosus to address challenges associated with assessing the dynamic nature of MeHg biogeochemistry and the difficulty of testing a heavily vegetated marsh sediment. After method development, we compared the bioavailability of MeHg in unamended sediment, sediment amended with powdered AC, and sediment amended with the commercial AC product SediMite. A subsequent study compared the bioavailability of MeHg in unamended sediment, sediment freshly amended with AC, and sediment amended with AC almost 2 years prior to the start of this study. Activated carbon amendments consistently reduced the bioavailability of MeHg to L. plumulosus , as indicated by a 2- to 4-fold decrease in the biota–sediment accumulation factor, which normalizes tissue concentrations to sediment concentrations. However, AC amendments increased sediment MeHg concentrations in five of seven studies, apparently by altering the balance between MeHg production and degradation. As a result, the net effect of AC amendment on absolute concentrations of MeHg in amphipods was mixed, with moderate reductions at some time points in some experiments but increasing concentrations or no effect in other cases. The AC amendments significantly decreased Hg and MeHg in porewater in all cases, however. A literature review of biota–sediment accumulation factors for other studies was also conducted. The mechanisms by which AC influences the physical and biogeochemical drivers of net methylation and concentrations of MeHg in sediment remain unclear. Any potential use of AC for Hg remediation should undergo site-specific testing before implementation.

Environmental Toxicology and Chemistry↗

USGS2025

Insights and strategic opportunities from the USGS 2024 Per- and Polyfluoroalkyl Substances (PFAS) Interagency Workshop

Introduction In 2021, the U.S. Geological Survey (USGS) published Circular 1490 titled, “Integrated Science for the Study of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) in the Environment: A Strategic Science Vision for the U.S. Geological Survey” (Tokranov and others, 2021). Circular 1490 was created to be a resource for USGS scientists prioritizing and planning research related to per- and polyfluoroalkyl substances (PFAS) and to be a guide for developing partnerships with other scientists, State and Federal agencies, and stakeholders engaged in PFAS research and management and mitigation of the environmental and human-health effects of PFAS. This USGS PFAS Strategic Science Vision document was intended to be the foundation for a “living strategic vision,” periodically providing updates on the state of USGS PFAS research, emerging PFAS data gaps and needs, and progress on interagency and stakeholder PFAS partnerships and priorities. To meet this objective, the USGS planned to host an Interagency and Stakeholder PFAS Workshop every 2–3 years. During September 10–12, 2024, the USGS hosted the first Interagency and Stakeholder PFAS Workshop in Reston, Virginia. The Workshop brought together experts from other Federal agencies (U.S. Environmental Protection Agency, National Institute of Environmental Health Sciences, Food and Drug Administration, Department of Defense [Air Force, Army]), State agencies (Washington Fish and Wildlife, Virginia Department of Transportation), and academia (Harvard University, University of Maryland) to address key challenges relating to the measurement and modeling of PFAS and the implications for environmental health. Participants engaged in in-depth discussions centered around six pivotal topics related to PFAS: (1) sampling protocols, methods and interpretation; (2) environmental sources, source apportionment, and occurrence; (3) environmental fate and transport; (4) human and wildlife exposure routes and risk; (5) bioconcentration, bioaccumulation, and biomagnification; and (6) ecotoxicology and effects. Each topic had three breakout sessions. A recurrent theme of workshop discussions was how data on a nationwide scale for PFAS occurrence in various environmental matrices, including air, water, food crops, biota, soil, and streambed sediment could help to advance scientific understanding. Participants noted significant geospatial data gaps, particularly in the midwestern and southern United States and the Pacific Northwest. PFAS data collection tends to be more robust along the eastern seaboard and in California. Participants stressed how enhancing the integration of large and small datasets across various agencies could help to support national scale understanding of PFAS. To address these gaps, attendees suggested leveraging datasets from Federal entities like the USGS and the U.S. Department of Defense, State agencies, and municipal utility services to develop predictive contaminant detection and transport models. Improved coordination between water quality programs and USGS research could help to facilitate access to valuable data, leading to comprehensive databases that inform PFAS point (wastewater treatment plants and landfills) and nonpoint (runoff from land, atmospheric deposition, food packaging) sources, environmental transport mechanisms, environmental detection and concentrations, potential exposure routes, and health effects on different biota, including humans. A specific request was made to develop a map demarking the depth of modern (1953 or later) groundwater, which is susceptible to surface-derived anthropogenic (that is, human-made) contamination, based on tritium-age dating. Emphasis was placed on incorporation of hydrology, groundwater flow paths, groundwater–surface water interactions, and landscape factors in predictive statistical models as a step to improve contaminant source identification and tracking. Molecular fingerprinting approaches garnered attention as techniques to link specific PFAS mixtures detected in a sample to environmental sources and levels in biota (Dávila-Santiago and others, 2022). Integrating data from abiotic (that is, water, soil, and air) and biotic (that is, living organisms) systems identified as a research opportunity. For example, understanding the composition of soils and sediments, which include a mixture of mineral, plant, and animal components, could advance understanding of exposure pathways. The discussions highlighted opportunities to explore and understand the potential redistribution and biotic exposures of PFAS from biosolid and wastewater treatment plant effluent land application practices, in addition to atmospheric releases and discharges from landfill and wastewater treatment plants. Participants identified research gaps surrounding how these sources may contribute to contamination and may affect surrounding ecosystems, including a better definition of anthropogenic background concentrations. Moving forward, the collection of co-occurrence data was noted as a means to improve understanding of complex mixtures and to leverage companion modeling efforts focused on areas with high and low contamination levels to identify areas of concern and unaffected resources. Participants emphasized how centralized USGS databases and the establishment of sample-metadata archives can help to ensure that samples are preserved and accessible for future research. In conclusion, the workshop participants identified opportunities to bridge data gaps and improve measurement techniques, modeling frameworks, databases, and communication, to enhance the understanding of PFAS and their effects on environmental and human health. Upon completion of the workshop, participants indicated an interest in developing strategic data collection, modeling, and analytical approaches to address these challenges.

Open-File Report↗

USGS2025

Evaluation of the effects of sediments contaminated by industrial discharges to a unionid mussel (Fatmucket, Lampsilis siliquoidea) and a common test benthic organism (Amphipod, Hyalella azteca)

Freshwater mussels are among the most sensitive species to a variety of chemicals in water exposures. However, few studies have been conducted to evaluate the effect of toxicants in sediments on mussels. Industrial discharges containing polyaromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and metals entered the Kanawha River surrounding Blaine Island, South Charleston, West Virginia, USA; a river which supports eight federally endangered mussel species. We collected sediment samples from a highly contaminated site, a nearby upstream site, and a further upstream reference site to assess the effects of contaminated sediment on the survival and growth of a unionid mussel (fatmucket, Lampsilis siliquoidea ) and a commonly tested benthic organism (amphipod, Hyalella azteca ) using standard 28-d sediment toxicity tests. We also determined mussel toxicity in a serial dilution of the highly contaminated sediment. Results showed that concentrations of PAHs, VOCs, and metals in the contaminated sediment were consistently greater than the other two sites. The mean survival of mussels and amphipods in the reference sediment was 100% and 95%, respectively, whereas the mean survival of both test species in the contaminated sediment was 0%. In the sediment dilution study, mean survival and biomass of mussels in the ≥6.25% treatment were significantly reduced relative to the control, with a 25% inhibition concentration of 4.1% for survival and 3.6% for biomass. We used sediment screening values and equilibrium partitioning sediment benchmarks to determine that nickel, mercury, and PAH mixture were likely responsible for the toxicity observed to mussels and amphipods and will provide critical data to identify and mitigate the sources of the mixture in contaminated sediment.

West Virginia↗

USGS2025

Real-time oil spill concentration assessment through fluorescence imaging and deep learning

Oil spills may pose severe ecological and socioeconomic threats, necessitating rapid and accurate environmental assessment. Traditional assessment methods used to determine the extent of a spill including gas chromatography-mass spectrometry, satellite imaging, and visual surveys, are often time-consuming, expensive, and limited by weather conditions or sampling constraints. Furthermore, these methods frequently struggle to provide real-time data crucial for prompt decision-making during spill emergencies. This study addresses these limitations by combining fluorescence imaging, deep learning, a mobile application, and a data management system for automated and real-time oil spill assessment. Our approach leverages a convolutional neural network architecture for feature extraction coupled with a custom regression model, trained and evaluated on a self-curated comprehensive dataset of 1,530 fluorescence images from two distinct oil types, a napthalenic crude oil and an aromatic-napthalenic crude oil, at concentrations ranging from 0 to 500 mg/L. The proposed approach demonstrates superior performance compared to both traditional machine learning models and more complex deep learning architectures, achieving an R² score of 0.9958 and RMSE of 9.28. The application enables rapid, cost-effective field measurements with robust data tracking and analysis capabilities. This research advances oil spill monitoring technology with a scalable solution that balances accuracy, speed, and accessibility for real-time environmental assessment and emergency response.

Journal of Hazardous Materials↗

USGS2025

Concentration dependency of PFOS bioaccumulation by freshwater benthic algae

Although perfluorooctanesulfonic acid (PFOS) has been voluntarily phased out, it remains the most abundant and frequently detected PFAS compound in biota worldwide. A deeper understanding of how PFOS enters the aquatic food web at the energetic base is needed to better characterize and predict the general patterns of PFAS trophic transfer. Research on bioaccumulation by primary producers remains limited. Because diatoms (Bacillariophyta) are often dominant constituents of aquatic biofilms, we exposed freshwater benthic diatoms ( Mayamaea atomus ) to a range of PFOS concentrations (0.01–100 μg/L) for 7 days in a controlled laboratory experiment to investigate PFAS bioaccumulation patterns. We quantified PFOS in water and algal matrices using liquid chromatography-tandem mass spectrometry and calculated bioconcentration factors (BCFs). Log PFOS concentrations in diatoms increased linearly with log 10 exposure concentration, corresponding to a sublinear relationship in arithmetic space. Consequently, BCF values decreased, from 4,831 to 174 L/kg, with increasing PFOS exposure, indicating concentration-dependent bioaccumulation consistent with higher-order organisms (e.g., Crustacea, Mollusca, Chordata). This pattern complicates the use of BCF for predictive purposes and may lead to mis-estimations of risk. Even as PFOS declines in the environment, algae will likely continue to accumulate and transfer PFOS and other PFAS to higher trophic levels.

ACS ES&T Water↗

USGS2025

Evaluating episodic sediment deposition zones in freshwater mussel habitats across Missouri, USA

Point-source sedimentation, such as spills from construction-related activities, can introduce substantial sediments into streams in the short term, potentially leading to mussel burial. To estimate downstream areas where freshwater mussels might face threats from sediment burial within the mussel habitats of Missouri streams and rivers, we examined 49 reaches where both field measurements and gaging data are available. We established empirical relationships for three flow classes to represent general flow conditions of all reaches. Using these hydraulic data, we employed a Lagrangian particle tracking model to simulate sediment transport under each condition, employing two sediment size ranges covering very fine sands to small gravels, resulting in 72 simulated scenarios. The model results indicate that sediments with diameters exceeding a critical value, ranging from 0.041 to 1.975 mm for varying velocities (ranging from 0.124 to 2.191 m/s) and depths (ranging from 1 to 12 m), settle in downstream locations. Potential settling sites span from tens to hundreds of meters downstream. The mode, median, and mean of sediment distribution generally fall within the range of 10–200 m based on particle count, while these values typically range from 1 to 100 m based on sediment mass.

Missouri↗

USGS2025

Acute Toxicity of 4-hydroxydiphenylamine (4-HDPA) and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPDQ), transformation products of 6PPD, to early instars of the mayfly, Neocloeon triangulifer

Our analysis of water samples collected during a rain event from two urban rivers in the Greater Toronto area, Ontario, Canada, indicated that selected transformation products (TPs) of the tire antioxidant, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), including 6PPD-quinone (6PPDQ) and 4-hydroxydiphenylamine (4-HDPA), were present at concentrations >1 µg/L. In acute (96-hr) toxicity tests with aquatic larvae of the mayfly Neocloeon triangulifer , 6PPDQ did not cause mortalities at the highest test concentration, which was just below the limit of solubility. In toxicity tests with 4-HDPA, a calculated 96-hr median lethal concentration of 339 µg/L is above environmentally relevant concentrations. However, in toxicity tests with 6PPD, there was evidence that the degradation of this tire wear compound produced unknown TPs that caused mortalities in exposed mayfly larvae. Additional work could identify other TPs of 6PPD that could be a hazard to aquatic invertebrates exposed to tire wear compounds transported into surface waters from transportation corridors.

Ontario↗

USGS2024

EthoCRED: A framework to guide reporting and evaluation of the relevance and reliability of behavioural ecotoxicity studies

Behavioural analysis has been attracting significant attention as a broad indicator of sub-lethal toxicity and has secured a place as an important subdiscipline in ecotoxicology. Among the most notable characteristics of behavioural research, compared to other established approaches in sub-lethal ecotoxicology (e.g. reproductive and developmental bioassays), are the wide range of study designs being used and the diversity of endpoints considered. At the same time, environmental hazard and risk assessment, which underpins regulatory decisions to protect the environment from potentially harmful chemicals, often recommends that ecotoxicological data be produced following accepted and validated test guidelines. These guidelines typically do not address behavioural changes, meaning that these, often sensitive, effects are not represented in hazard and risk assessments. Here, we propose a new tool, the EthoCRED evaluation method, for assessing the relevance and reliability of behavioural ecotoxicity data, which considers the unique requirements and challenges encountered in this field. This method and accompanying reporting recommendations are designed to serve as an extension of the “Criteria for Reporting and Evaluating Ecotoxicity Data (CRED)” project. As such, EthoCRED can both accommodate the wide array of experimental design approaches seen in behavioural ecotoxicology, and could be readily implemented into regulatory frameworks as deemed appropriate by policy makers of different jurisdictions to allow better integration of knowledge gained from behavioural testing into environmental protection. Furthermore, through our reporting recommendations, we aim to improve the reporting of behavioural studies in the peer-reviewed literature, and thereby increase their usefulness to inform chemical regulation.

Biological Reviews↗

USGS2024

Evaluation of short-term mussel test for estimating toxicity

Effect concentrations of ammonia, nickel, sodium chloride, and potassium chloride from short-term 7-day tests were compared to those from standard chronic 28-day toxicity tests with juvenile mussels (fatmucket, Lampsilis siliquoidea ) to evaluate the sensitivities of the 7-day tests. The effect concentrations for nickel (59 µg Ni/L), chloride (316–519 mg Cl/L, a range from multiple tests), and potassium (15 mg K/L) obtained from the 7-day tests were within a range of effect concentrations for each corresponding chemical in the 28-day tests (41–91 µg Ni/L, 251–>676 mg Cl/L, 15–23 mg K/L), whereas the 7-day ammonia effect concentration (0.40 mg/L total ammonia nitrogen; TAN) was up to 3.3-fold greater than the 28-day effect concentrations (0.12–0.36 mg TAN/L) but with overlapped 95% confidence limits. These results indicate that the 7-day tests produced similar estimates compared to the 28-day tests. Further studies are needed to evaluate the 7-day test sensitivity using additional chemicals with different modes of toxic action. Environ Toxicol Chem 2024;00:1–6. Published 2024. This article is a U.S. Government work and is in the public domain in the USA.

Environmental Toxicology and Chemistry↗

USGS2024

Development of high surface area organosilicate nanoparticulate thin films for use in sensing hydrophobic compounds in sediment and water

The scope of this study was to apply advances in materials science, specifically the use of organosilicate nanoparticles as a high surface area platform for passive sampling of chemicals or pre-concentration for active sensing in multiple-phase complex environmental media. We have developed a novel nanoporous organosilicate (NPO) film as an extraction phase and proof of concept for application in adsorbing hydrophobic compounds in water and sediment. We characterized the NPO film properties and provided optimization for synthesis and coatings in order to apply the technology in environmental media. NPO films in this study had a very high surface area, up to 1325 m 2 /g due to the high level of mesoporosity in the film. The potential application of the NPO film as a sorbent phase for sensors or passive samplers was evaluated using a model hydrophobic chemical, polychlorinated biphenyls (PCB), in water and sediment. Sorption of PCB to this porous high surface area nanoparticle platform was highly correlated with the bioavailable fraction of PCB measured using whole sediment chemistry, porewater chemistry determined by solid-phase microextraction fiber methods, and the Lumbriculus variegatus bioaccumulation bioassay. The surface-modified NPO films in this study were found to highly sorb chemicals with a log octanol-water partition coefficient (K ow ) greater than four; however, surface modification of these particles would be required for application to other chemicals.

Biosensors↗

USGS2024

Evaluation of chronic effects of potassium chloride and nickel on survival, growth, and reproduction of a unionid mussel (Lampsilis siliquoidea)

The ASTM International standard test method for freshwater mussels (E2455‐13) recommends 4‐week toxicity testing with juveniles to evaluate chronic effects on survival and growth. However, concerns remain that the method may not adequately address the sensitivity of mussels to longer term exposures (>4 weeks), particularly in relation to potential reproductive impairments. No standard method directly evaluates toxicant effects on mussel reproduction. The objectives of the present study were to (1) evaluate toxicity endpoints related to reproduction in fatmucket ( Lampsilis siliquoidea ) using two common reference toxicants, potassium chloride (KCl) and nickel (Ni); (2) evaluate the survival and growth of juvenile fatmucket in standard 4‐week and longer term (12‐week) KCl and Ni tests following a method refined from the standard method; and (3) compare the sensitivity of the reproductive endpoints with the endpoints obtained from the juvenile mussel tests. Reproductive toxicity tests were conducted by first exposing female fatmucket brooding mature larvae (glochidia) to five test concentrations of KCl and Ni for 6 weeks. Subsamples of the glochidia were then removed from the adults to determine three reproductive endpoints: (1) the viability of brooded glochidia; (2) the viability of free glochidia in a 24‐h exposure to the same toxicant concentrations as their mother; and (3) the success of glochidia parasitism on host fish. Mean viability of brooded glochidia was significantly reduced in the high KCl concentration (26 mg K/L) relative to the control, with a 20% effect concentration (EC20) of 14 mg K/L, but there were no significant differences between the control and any Ni treatment (EC20 > 95 µg Ni/L). The EC20s for viability of free glochidia after the additional 24‐h exposure and parasitism success were similar to the EC20s of brooded glochidia. The EC20s based on the most sensitive biomass endpoint in the 4‐week juvenile tests were 15 mg K/L and 91 µg Ni/L, similar to or greater than the EC20s from the reproductive KCl and Ni tests, respectively. When exposure duration in the juvenile tests was extended from 4 to 12 weeks, the EC20s decreased by more than 50% in the KCl test but by only 8% in the Ni test. Overall, these results indicate that a standard 4‐week test with juvenile mussels can prove effective for estimating effects in chronic exposures with different life stages although a longer term 12‐week exposure with juvenile mussels may reveal higher sensitivity of mussels to some toxicants, such as KCl.

Environmental Toxicology and Chemistry↗

USGS2024

Guide to per- and polyfluoroalkyl substances (PFAS) sampling within Natural Resource Damage Assessment and Restoration

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals with a nondegradable fluorinated carbon backbone that have been incorporated in countless industrial and commercial applications. Because PFAS are nondegradable, they have been detected in all environmental media, indicating extensive global contamination. The unique physiochemical properties of PFAS and their complex interactions with environmental matrices create a great challenge for researchers when selecting site-specific sample matrices, sampling logistics, various analytical methods, and data interpretation. The widespread contamination and the potential toxicity of PFAS to human and environmental health have resulted in the proposed designation of two commonly used PFAS as hazardous substances, which may prompt new requirements for reporting, regulatory action, and site cleanup. For researchers involved in natural resource damage assessment efforts, understanding the multifaceted dynamics of the environmental fate and transport of PFAS will be essential for appropriate sample collections, analyses, and data interpretation. This guide aims to provide fundamental concepts and considerations involved with environmental sampling for PFAS during site assessments.

Open-File Report↗

USGS2024

A model for evaluation of sediment exposure and burial for freshwater mussels from heavy particle sedimentation

Freshwater mussels (Bivalvia: Unionida) are an ecologically important faunal group. Excessive sediments, both in suspended and deposited formats, are believed to have negative effects on survival of freshwater mussels. However, there is a lack of quantitative tools for assessing the impact of abrupt and excessive sedimentation on freshwater mussel habitats. This gap in knowledge poses challenges for construction planning that necessitates evaluating sedimentation effects on mussels. In this paper, we present a simple Lagrangian particle tracking (LPT) model designed to investigate the downstream distances from the sediment release point where mussels may face risks of sediment exposure and burial during episodic sedimentation events. We validated the model in predicting the deposition of sands ranging from 125 to 625 μ m "> 625μm in diameter within an open channel. Subsequently, we applied the LPT model to a representative stretch of mussel habitats in the lower Osage River, Missouri, USA. Implementing the LPT model using computational fluid dynamics analysis of river hydrodynamics, we investigated the downstream distances impacted by a hypothetical sedimentation event. The results indicate that the mussels within tens and hundreds of meters may be at risk of burial under low and high flow conditions, respectively. Mussels within hundreds and potentially thousands of meters may be at risks of sediment exposure under low and high flow conditions, respectively. The impacted distance is highly dependent on the sediment diameters and flow conditions. These results contribute valuable insights into the potential impacts of sedimentation on freshwater mussel habitats, aiding in informed decision-making for construction projects near these critical aquatic ecosystems.

Ecological Modelling↗

USGS2023

Responses of juvenile mussels to metals in sediment and water of the Tri-State Mining District

The U.S. Geological Survey and collaborators from EcoAnalysts, Inc., completed field and laboratory studies during 2016–19 to evaluate the toxicity of metals to freshwater mussels in streams draining the Tri-State Mining District. This project consisted of (1) sampling and analysis of metals in water and sediment, (2) surveys of mussel assemblages at sites with suitable mussel habitat, (3) toxicity tests with juvenile mussels exposed to zinc or to a mixture of metals (zinc, lead, and cadmium) in water, and (4) toxicity tests to evaluate the contributions of metals in sediment and metals in overlying water to toxic effects on mussels. Field sampling at sites in the Spring River and Neosho River and their tributaries demonstrated wide ranges of metal contamination in water and sediment. Zinc was the predominant toxic metal in water, and concentrations of lead and cadmium were much lower. Mussel areal density and species richness were greater at reference sites with low sediment metal concentrations (for example, zinc, 29–141 micrograms per gram) than at test sites that had higher concentrations of sediment zinc (416–3,420 micrograms per gram) as a result of effects of upstream mining activity. Juvenile mussels were highly sensitive to zinc in water in 12-week toxicity tests compared to previous water-only tests, and adding low levels of waterborne lead and cadmium typical of their occurrence in Tri-State Mining District streams produced greater toxicity. Thresholds for mussel toxicity were at or less than waterborne metal concentrations detected in Tri-State Mining District streams, and sites with waterborne metal concentrations exceeding thresholds had decreased mussel density and decreased mussel species richness. The 12-week toxicity tests with juvenile mussels in Tri-State Mining District sediments also demonstrated negative mussel responses with metal exposure. Thresholds for reductions in survival, growth, or biomass were at sediment metal concentrations less than thresholds reported for previous 4-week tests. We documented strong associations between reduced survival in laboratory tests and reduced species richness in community surveys. Attempts to estimate combined toxicity thresholds for metals in sediment and overlying water were not successful. These inconclusive results may be attributable to several factors, including (1) unexpected losses of waterborne metals from solution, (2) differences in sensitivity of different age/size classes of juvenile mussels, (3) disruption of sediment-water equilibria and changes in metal bioavailability, and (4) behavioral or physiological responses allowing juvenile mussels to temporarily reduce or avoid metal exposure. We also observed differences in metal toxicity thresholds between sediment toxicity tests started with different ages/sizes of test organisms. A followup study that combined exposure to Tri-State Mining District sediments with exposures to multiple levels of waterborne metals demonstrated toxic effects of sediments with low metal concentrations; however, some treatments also indicated unexpected reversals of concentration-response trends and reduced toxicity in treatments that had high metal concentrations in overlying water. These unusual responses may reflect development of physiological tolerance to metal toxicity by induction of metal-binding proteins (for example, metallothionein) in response to high metal levels in water. Results of laboratory and field studies indicated strong associations between metal exposure in Tri-State Mining District streams and toxic effects on juvenile freshwater mussels. Mussel community characteristics corresponded to differences in metal concentrations in sediment and water among Tri-State Mining District sampling sites. Responses of juvenile mussels in 12-week water and sediment exposures were strongly correlated with the status of mussel assemblages in Tri-State Mining District streams. The combined results support the hypothesis that exposure to metals from historical mining activities adversely affects freshwater mussel communities in the Spring River/Neosho River drainage.

Kansas, Missouri, Oklahoma↗

USGS2023

Laboratory-derived bioaccumulation kinetic parameters for four per- and polyfluoroalkyl substances in freshwater mussels

Although freshwater mussels are imperiled and identified as key conservation priorities, limited bioaccumulation information is available on these organisms for contaminants of emerging concern. In the present study we investigated the bioaccumulation of per- and polyfluoroalkyl substances (PFAS) in the model freshwater pond mussel Sagittunio subrostratus because mussels provide important ecosystem services and are important components of aquatic systems where PFAS occur. In the present study we selected four representative perfluorinated carboxylic acids and sulfonic acids, then determined the bioaccumulation kinetics of freshwater mussels in a controlled laboratory study. Because uptake ( k u ) and elimination ( k e ) rate constants and time to steady state are important parameters for food web bioaccumulation models, we derived bioaccumulation kinetic parameters following exposure to perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), and perfluorodecanoic acid (PFDA) at 10 µg/L and perfluoroundecanoic acid (PFUnDA) at 1 µg/L during a 14-day uptake period followed by a 7-day elimination period. Kinetic and ratio-based bioaccumulation factors (BAFs) were subsequently calculated, for example ratio-based BAFs for mussel at day 7 were determined for PFHxS (0.24 ± 0.08 L/kg), PFOS (7.73 ± 1.23 L/kg), PFDA (4.80 ± 1.21 L/kg), and PFUnDA (84.0 ± 14.4 L/kg). We generally observed that, for these four model PFAS, freshwater mussels have relatively low BAF values compared with other aquatic invertebrates and fish.

Environmental Toxicology and Chemistry↗