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
06:00 PM
Determination of platinum concentration in macroalgae (8800)
Primary Presenter: Ziwei Li, Kanazawa University (liziwei@stu.kanazawa-u.ac.jp)
Platinum (Pt) has been used extensively in automotive catalysts and anti-cancer drugs, resulting in elevated concentrations in the environment. Determination the amount of Pt in the environment is crucial, as its accumulation can lead to contamination. To detect the Pt concentration in the natural environment and evaluate anthropogenic effects in coastal areas, Undaria pinnatifida was used because of its high capacity to absorb platinum group elements and its status as a common edible macroalgae in Japan. In this research, we established analytical methods of Pt in macroalgae. By adjusting the amount of HF added during the digestion process, the optimal amount was determined to be 0.24 mL/g of 49.5% HF. Additionally, the addition of 3.5mL of 30% HCl effectively reduced the formation of white precipitate and improved the recovery rate. The established method for analyzing Pt concentration in U. pinnatifida was 5 ppt for detection limit and 16 ± 7 ppt for blank value. The concentration of Pt U. pinnatifida wakame from the sampling sites was measured by using the established method. The result shows that the concentration of Pt in the stem and sporophylls began to decrease from the outside to the inside of the bay, while the concentration in the roots showed the opposite tendency. This suggests that the above-ground and below-ground organs of U. pinnatifida are affected by different sources of Pt.
06:00 PM
IMPACT OF CHANGING ENVIRONMENTAL CONDITIONS ON DESORPTION OF PFAS FROM SEDIMENTS IN LACUSTRINE ENVIRONMENTS (9183)
Primary Presenter: Lauren McShea, University of North Carolina at Chapel Hill (lmcshea@unc.edu)
Per- and poly-fluoroalkyl substances (PFAS) are persistent environmental contaminants characterized by their chemical stability, bio-accumulative effects, and ability to absorb onto particle surfaces, allowing a reservoir of historic PFAS species to build in accreting sediments. Seasonal stratification driven by the warming of surface waters and inflow stagnation in lakes exposes sediments to alkaline and hypoxic water conditions. The effect of these conditions on the desorption of PFAS from sediment particles is of interest, as desorption into the water column would be a potential compounding contamination source in drinking water. North Carolina has multiple significant PFAS sources contributing to contamination in primary drinking water systems. Jordan Lake has a dam-controlled inflow and receives 80% of its consistent sediment accumulation from the highly industrially contaminated Haw River, allowing it to act as a PFAS deposit. A well-characterized sediment core from Jordan Lake with known PFAS concentrations was processed and exposed to a range of alkaline and hypoxic conditions to mimic those experienced by turbid bottom sediments during seasonal stratification. The concentration of contaminants in the water column after exposure was quantified and compared to the known PFAS concentration in respective sediment layers to determine the potential for desorption in the sediment. The findings of this study are significant in understanding the contribution of PFAS desorption to drinking water contamination and the potential effects of larger-scale sediment disturbance.
06:00 PM
Concentrations and transport pathways of microplastics in a coastal estuary (9360)
Primary Presenter: Karl Kaiser, Texas A&M University at Galveston (kaiserk@tamug.edu)
Plastics underpin modern human life, but its accumulation in natural environments poses a significant threat to biological organisms and foodwebs. Microplastics (<5 mm) represent the majority (>70%) of plastic emissions and act as important carriers of pollutants. This study combined measurements of microplastics in surface waters and microplastic settling behavior with a coupled hydrodynamic sediment wave model to study the transport of microplastics during normal conditions and an extreme storm event in Galveston Bay, Texas (USA). The Galveston Bay watershed is a major center of plastic production and shipping in the USA. Microplastics were identified and quantified by pyrolysis gas chromatography tandem mass spectrometry. This allowed the identification and quantification of microplastics at ultra-low levels (≥1 ng) without matrix interference. Settling behavior of microplastic aggregates was investigated with elutriation tubes that yielded information on settling velocities relative to microplastic content, composition, and association with organic and inorganic debris. Surface waters in Galveston Bay showed polypropylene (PP), polyvinyl chloride (PVC), nylon-66 (N66), polyethylene terephthalate (PET), and polyethylene (PE), with total concentrations ranging from 0.5-42.9 µg L-1. The coupled hydrodynamic sediment wave model helped resolve the highly variable microplastic concentrations and compositions in the bay system. Additional parameterization of microplastic behavior in sediments will provide a better understanding of estuarine retention and export ability.
06:00 PM
DAILY VARIABILITY OF NATURALLY OCCURRING WATERBORNE PATHOGENS IN A STREAM SYSTEM (9443)
Primary Presenter: Elisabeth Drake, University of Georgia (ebd36516@uga.edu)
Surface waters are an important source for recreation and irrigation but can be reservoirs of pathogens. There has been considerable work on surface water contamination with enteric pathogens, but we know less about the frequency and distribution of naturally occurring pathogens, and their contribution to microbial communities in stream systems. The objective of this work was to identify and evaluate population dynamics of presumptive Aeromonas and Vibrio and microbial composition in a freshwater stream over a daily time series. Water samples were collected from May through December 2024, filtered onto membranes and used for total community DNA extraction and culturing on TCBS agar. Two well-isolated colonies were picked for each sample and streaked for purification. Isolates were screened as presumptive Vibrio and Aeromonas using genus specific qPCR assays. Most isolates were identified as presumptive Aeromonas but genome sequencing suggests this includes other opportunistic pathogens as well. Presumptive Aeromonas and Vibrio copies/mL were determined from total community DNA extracts, resulting in a wide range of copies per mL over the study period. Concentrations were highest in the summer months, suggesting a seasonal variability in distribution. Additional work will evaluate the broader microbial community composition and explore species specific distribution using whole genome sequencing and targeted PCR. This work will address the scale of naturally occurring bacterial pathogens in a freshwater system and their ecological impact including risks to humans and animals.
06:00 PM
DEVELOPING ANALYTICAL PROTOCOLS FOR 6PPD-Q IN NATURAL WATERS (9518)
Primary Presenter: Jack Lloyd, The University of Texas at Austin (jack.lloyd@utexas.edu)
6PPD-quinone (6PPD-Q), as an oxidized product of 6PPD, is highly toxic and causes the acute mortality of coho salmon (Oncorhynchus kisutch). However, analyzing 6PPD-Q in natural waters can be challenging due to its amphiphilic properties and interference with natural particles and dissolved organic matter. In this study, we sought to develop a streamlined protocol of extracting and analyzing 6PPD-Q in natural waters. We tested how different types of solid phase extraction (SPE) cartridge, filter size, and salinity affected the extraction efficiency of 6PPD-Q in seawater using LC-MS. Also tested were the effects of solvent (ACN vs DMSO), freezing and thawing of DMSO, sonication, and bottle type (plastic vs glass) on the measured concentration of 6PPD-Q. For seawater samples, pre-filtration through 0.2 µm filters and Oasis Prime HLB delivered the best recovery rates of 6PPD-Q, while salinity had no significant effect. Sonicating as well as freezing and thawing samples in DMSO improved recovered 6PPD-Q concentrations, and the measured concentration of 6PPD-Q was higher when using glass bottles. The matrix in which 6PPD-Q is prepared makes a difference: DMSO increased the responding factor of 6PPD-Q in LC-MS compared with ACN, and the effect was most pronounced at higher 6PPD-Q concentrations. Recommended instrumental conditions are suggested, such as mobile phase, column, m/z ratio, and linear range. Finally, field data utilizing these methods are presented. Overall, this work provides an efficient streamlined protocol for extracting and analyzing 6PPD-Q in natural waters.
06:00 PM
Photooxidation of Tire Wear Particles Leachate in Controlled Physiochemical Conditions (9736)
Primary Presenter: Leah Cogar, Texas A&M University-Corpus Christi (lcogar@islander.tamucc.edu)
Tire wear particles (TWPs) from routine road use are a major source of non-exhaust emissions, with significant environmental presence. Understanding the fates of pollutants within these particles is crucial. TWPs contain various components, including additive chemicals, aromatic oils, synthetic rubbers, and natural rubbers. Compounds like 6PPD, its oxidized form 6PPD-quinone, and Hexamethoxymethylmelamine (HMMM) are of particular concern due to their acute and chronic toxicity to aquatic organisms. These compounds and their transformation products, formed through photodegradation and other processes, have been detected in water bodies, especially following road runoff after rainfall, indicating their persistence. This study examines the photooxidation of leached chemical additives from TWPs under controlled conditions using UPLC-Orbitrap Mass Spectrometry for high-resolution mass measurements, employing targeted and untargeted approaches. Tire particles were incubated in Milli-Q water, artificial seawater, and sterilized Lavaca River water for 2 days, followed by exposing the leachate to simulated solar radiation for 3 days to monitor the degradation and transformation. While research is ongoing, preliminary data reveal insights into the degradation rates of 6PPD, the photoproduction of 6PPD-Q and other leachate compounds. This study contributes to a more comprehensive understanding how environmental factors influence solar-driven breakdown and formations of various tire additives compounds when released into aquatic ecosystems.
06:00 PM
HEAVY METAL CONTAMINATION IN SEDIMENTS FROM ANTHROPOGENIC SOURCES OFFSHORE OF HAVANA BAY, CUBA (9742)
Primary Presenter: Rosalie Cruikshank, Eckerd College (rkcruikshank@gmail.com)
Sediment cores were collected off the northwest coast of Cuba in 2017 to evaluate sedimentation patterns and anthropogenic influences. Potential anthropogenic influences on sediments include industrial activity, wastewater dumping, strip mining, and dredging, which can contribute to heavy metal contamination in the marine environment. Heavy metals are persistent in the environment and can have adverse health effects on both marine organisms and human health. Sediment cores were analyzed by X-Ray Fluorescence for elemental composition and sedimentology (texture and composition). Age control and accumulation rates were determined using short-lived radioisotope chronologies (excess Pb-210 using CRS model). Concentrations of heavy metals, particularly Copper, Zinc and Arsenic, and sometimes Zircon, Lead, and Nickel, were above the United States Environmental Protection Agency chronic marine sediment quality criteria. Concentrations of heavy metals decreased with increasing distance offshore of Havana Bay and distance to the west. In a transect of cores offshore from Havana Bay, the concentrations peaked around the 1970s at the site closest to shore (150m water depth), and around the 2010s in the furthest offshore (750m water depth). This could indicate a lag in sediment transport and deposition with increasing distance offshore. After peaking, the metal concentrations typically remained above background levels until present day. Locating input source(s) would assist in determining how to minimize their impact or potential mitigation efforts.
SS16P - Emerging Chemical and Biological Contaminants in Aquatic Ecosystems
Description
Time: 6:00 PM
Date: 29/3/2025
Room: Exhibit Hall A