Biological and chemical contaminants enter aquatic ecosystems from both land and the atmosphere. Biological contaminants include viruses, bacteria, and parasites that infect humans, wildlife, or livestock. These enter our waterways through untreated sewage or wastewater, or via run-off from forests, agricultural fields, concentrated animal growth operations on land, or intensive aquaculture operations. Chemical contaminants also enter via these routes and occur in a wide variety of forms including organic nutrients, pesticides, herbicides, industrial products (e.g., PFAS and 6ppd- quinone), personal care products, pharmaceuticals, microplastics, and heavy metals. Many chemicals, especially PFAS, 6ppd-quinone, and microplastics are considered “contaminants of emerging concern” due to their longevity and potential for biomagnification in food webs. Inputs of many contaminants are poorly regulated, so concentrations are steadily increasing in aquatic ecosystems. Contaminants in surface waters may have direct effects on human health but may also profoundly influence aquatic ecosystems through indirect impacts on aquatic biota, resulting in poor water quality. The central focus of this session will be oral presentations on the quantification of environmental concentrations of these compounds in aquatic ecosystems, information on the real and potential impacts on biota (aquatic and human), characterizing biomarkers to demarcate exposure and adverse effects, new detection technologies, and strategies for mitigating contaminant impacts within these systems.
Lead Organizer: James Pinckney, University of South Carolina (pinckney@sc.edu)
Co-organizers:
David Hala, Texas A&M - Galveston (halad@tamug.edu)
Antonietta Quigg, Texas A&M - Galveston (quigga@tamug.edu)
Karl Kaiser, Texas A&M University - Galveston (kaiserk@tamug.edu)
Catherine Schlenker, University of South Carolina (schlenkc@email.sc.edu)
Presentations
02:30 PM
Examining the impact of emerging contaminants on phytoplankton mortality, photosynthetic capacity, and community composition in South Carolina lakes (8949)
Primary Presenter: Catherine Schlenker, University of South Carolina (schlenkc@email.sc.edu)
Humans rely on freshwater for vital services like drinking water, agriculture, and hygiene, yet are a top source of water quality decline. Of particular concern is the introduction of contaminants including pharmaceuticals, persistent organic pollutants, forever chemicals, and tire wear products, among others. This project aims to investigate how natural phytoplankton communities respond to exposure to four emerging contaminants: carbamazepine and diclofenac (pharmaceuticals), perfluorooctane sulfonic acid (PFOS, a persistent organic pollutant), and 6ppd-quinone (tire wear product). Each of the four contaminants has been demonstrated to cause harm to aquatic organisms across all trophic levels, but studies involving phytoplankton have focused on cultures rather than natural communities. In this study, we exposed whole water samples from Lake Murray, South Carolina to a range of environmentally relevant concentrations of each contaminant. We use High Performance Liquid Chromatography (HPLC) to determine total chlorophyll a concentration as a proxy for phytoplankton biomass and photopigment concentrations to determine group-specific responses. We also use Pulse Amplitude Modulated Fluorometry to assess photosynthetic capacity. Preliminary results suggest that at these concentrations, contaminants do not impact total biomass or photosynthetic capacity. Due to their position as the base of the aquatic food web and their role in nutrient cycling, understanding how phytoplankton respond to these ubiquitous compounds is crucial for understanding and managing ecosystem health.
02:45 PM
FRESHWATER-SALTWATER FRONTIERS: TAXON-SPECIFIC BIOACCUMULATION OF POLYFLUOROALKYL-SUBSTANCES IN ESTUARINE ZOOPLANKTON OFF THE CAPE FEAR REGION, NC (9201)
Primary Presenter: Gena Leib, University of North Carolina Wilmington (gml5089@uncw.edu)
Rivers discharging into the ocean can be vectors for the transport of contaminants accumulated from large basins. Such contaminants include Polyfluoroalkyl-Substances (PFAS), whose strong and stable carbon-fluorine bonds, can have lasting effects on aquatic natural ecosystems where research is limited in planktonic biota. To understand the drivers of accumulation of these chemicals, we are investigating the potential bioaccumulation of PFAS in zooplankton functional groups off the Cape Fear River. To test for PFAS bioaccumulation, we collected concurrent samples of zooplankton biomass and water samples. We hypothesize higher concentrations in benthic versus pelagic groups due to differential exposure. River-exposed species are expected to have higher concentrations than oceanic ones, reflecting sources. We expect differences in concentrations between distinct trophic functional groups. Preliminary data identified significant concentrations of PFAS compounds in zooplankton biomass but not in the aqueous phase, suggesting bioaccumulation in zooplankton. The main compounds detected in zooplankton biomass samples were PFBA, PFHxA, PFOA, PFHpA, PFDA, and PFOS. Average concentrations were highest for PFHxA (143 ng/g), PFBA (98 ng/g), and PFOA (54 ng/g). Understanding the spatial (river, estuary, coastal and offshore) variability of contaminants will allow us to understand bioaccumulation patterns in different zooplankton functional groups especially where hydrographic regimes changes are expected to exert significant pressure on planktonic assemblages due to global change.
03:00 PM
ANTIBIOTIC MULTI RESISTANCE OF CORAL-ASSOCIATED BACTERIA IN COMAU FJORD, CHILE (9128)
Primary Presenter: Anna Berezkina, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) (anna.berezkina@awi.de)
Chile is the world's second largest salmon producer after Norway, however, known for its higher application of antibiotics during rearing in the ocean. This raises concern about its impact on native benthic fauna, like the dense cold-water coral (CWC) banks in the fjords like Comau Fjord. We sampled the common CWC Desmophyllum dianthus close and distant from salmon farm activity. 46 bacterial strains were isolated to assess their resistance to antibiotics using the Kirby-Bauer disc diffusion method. A total of 15 antibiotics were tested including the four most commonly applied antibiotics in salmon farm activity (florfenicol, oxytetracycline, tilmicosin, erythromycin) in addition to commonly used antibiotics in human disease treatment and environmental studies in the region. High antibiotic resistance was found across sites and taxa (mean ± se: 7.0 ± 0.35) with a slight but significantly higher resistance in bacteria cultured from corals collected near compared to distant from salmon farms (7.7 ± 0.47 versus 6.3 ± 0.48, respectively, p = 0.02592). The cultured microbiome indicates a shift from a Pseudoalteromonas-dominated to a Shewanella-dominated microbiome in corals near the salmon farm. This aligns with a shift in the community composition of coral-associated bacteria identified by culture-independent 16S rRNA amplicon sequencing and the dominance of certain taxa close to salmon farms. Together this may suggest that salmon farm activity has the potential to affect benthic organisms and contribute to the spread of bacterial antibiotic resistance within this fjord system.
03:15 PM
UPTAKE AND EFFECTS OF PFAS ON ANIMAL SPECIES IN SALTMARSH ECOSYSTEMS (9403)
Primary Presenter: Raven Ferguson, Oak Ridge Institute for Science and Education (raven.ferguson@noaa.gov)
PFAS exposure can have negative health impacts on many terrestrial, aquatic, and marine species, but data specifically on saltmarsh species are lacking. To address this gap, we examined the uptake and effects of two PFAS compounds, PFOA and PFOS, on hard clams (Mercenaria mercenaria), mud snails (Tritia obsoleta), amphipods (Leptocheirus plumulosus), grass shrimp (Palaemonetes pugio), and sheepshead minnows (Cyprinodon variegatus) in simulated marsh ecosystems (mesocosms) also filled with marsh sediment, seawater, and smooth cordgrass (Spartina alterniflora). Each mesocosm remained as a control or was dosed with 7 mg/L PFOA, 70 mg/L PFOA, 0.55 mg/L PFOS, 5.5 mg/L PFOS, or a combination of 0.55 mg/L PFOS and 7 mg/L PFOA for a total of four mesocosms per treatment. Low PFOA (7 mg/L) and PFOS (0.55 mg/L) doses were chosen to correspond with the EPA’s acute saltwater aquatic life benchmarks meant to protect saltwater species. Following 32 days of exposure, there was significant PFAS uptake for all species with amphipods having the largest PFOA tissue concentrations and sheepshead having the largest PFOS concentrations. PFAS treatment was also shown to have a significant, negative effect on grass shrimp, clam, and amphipod survival, but not sheepshead or mud snail survival. At the EPA’s acute saltwater aquatic life benchmark for PFOA, only the survival of amphipods was reduced, while no species’ survival was impacted at the PFOS benchmark level. While more research is warranted, the uptake and effects of PFAS varied based on PFAS compound and species.
03:30 PM
A MARINE MODEL FOR PFOA REPLACEMENTS: A CASE STUDY ON THE ENVIRONMENTAL FATE HFPO-DA (GenX) (9692)
Primary Presenter: Johannes Bieser, Helmholtz Zentrum Hereon (johannes.bieser@hereon.de)
Per- and polyfluoroalkyl substances (PFAS) are anthropogenic persistent and toxic chemicals. The most common PFAS is perfluorooctanoic acid (PFOA) which has been produced on an industrial scale since the 1950ties. Since the early 2000s the industry has started to replace PFOA with alternative PFAS. One such replacement, advertised under the name GenX, is hexafluoropropylene oxide dimer acid (HFPO-DA). Replacing PFOA with a multitude of alternative PFAS poses a severe problem. Because analytical methods are not available for many of the replacement substances they can be emitted secretly into the environment. For HFPO-DA, our Institute developed a method that allows to detect this substance at environmental levels and we found that it was a major replacement in Europe’s largest PFAS production plant in the Netherlands. First traces were found in the river Rhine in 2008 and in 2015 HFPO-DA concentrations already surpassed those of PFOA. A peak in HFPO-DA production was observed in 2017 and now the replacement seems to have been replaced itself. Based on this well documented episode of HFPO-DA emissions by a major point source into the river Rhine over a period of 16 years we performed a model study to investigate the environmental fate of HFPO-DA. Based on measurements in the North Sea and the North Atlantic Ocean we were able to validate the model for HFPO-DA. This case study is meant to show the feasibility of modelling PFOA replacements in the marine environment. For many of the hundreds of PFOA replacements that are currently in use there are no or only limited observations available. This means that through the replacement of PFOA we are blind to the real extend of PFAS contamination today. Models can allow us to estimate the production capacities even if measurements are only available years after the initial emission of the replacement substance.
SS16B - Emerging Chemical and Biological Contaminants in Aquatic Ecosystems
Description
Time: 2:30 PM
Date: 30/3/2025
Room: W201CD