Anthropogenic pollutants are ubiquitous across environmental media, including air, water, sediment, and biota. While the role of legacy pollutants in aquatic systems has been well-documented, much of their fate and interactions with diverse ecosystem components and functions are still poorly understood. Emerging pollutants (e.g., pesticides, flame retardants) challenge our understanding of the full effects of contaminants in the environment. Emerging methodologies, including targeted and non-targeted laboratory analyses, and modeling approaches continue to better define the fate of these pollutants. This session welcomes abstracts focusing on any combination of field, laboratory, and modeling studies focusing on source, fate, and transport of emerging and legacy pollutants through aquatic systems. We welcome studies using transdisciplinary approaches and integrating across the freshwater-to-marine continuum to improve mechanistic understanding of pollutants in aquatic ecosystems.
Lead Organizer: Christopher Filstrup, University of Minnesota Duluth (filstrup@d.umn.edu)
Co-organizers:
Kathryn Schreiner, University of Minnesota Duluth (kschrein@d.umn.edu)
Euan Reavie, University of Minnesota Duluth (ereavie@d.umn.edu)
Bridget Ulrich, University of Minnesota Duluth (ulrichb@d.umn.edu)
Chan Lan Chun, University of Minnesota Duluth (chun0157@d.umn.edu)
Brian Lenell, U.S. Environmental Protection Agency, Great Lakes National Program Office (lenell.brian@epa.gov)
Presentations
03:00 PM
METALS SPATIAL DISTRIBUTION AND TEMPORAL TRENDS IN LAKE SUPERIOR SEDIMENT REFLECT ANTHROPOGENIC SOURCES (6764)
Primary Presenter: Christopher Filstrup, University of Minnesota Duluth (filstrup@d.umn.edu)
Heavy metals used in industrial and manufacturing processes can present health and management challenges when they accumulate in aquatic ecosystems. While the fate and transport of certain legacy metals (e.g., mercury) are well-studied, there are critical knowledge gaps in the spatial distribution and temporal patterns of metals in the Laurentian Great Lakes in relation to changes in industrial uses within the watershed and airshed. As part of the EPA Great Lakes Sediment Surveillance Program, we analyzed metals in surface sediments and sediment cores collected throughout Lake Superior to identify tributary sources of metals, better understand their fate and burial, and evaluate how concentrations have changed through time. Preliminary findings indicate that metals distributions in surface sediments (< 5 y) reflect the underlying geology and industrial activities (e.g., mining, forestry) in the watershed: (1) lead and copper were highest between Isle Royale and the Keweenaw Peninsula; (2) mercury concentrations were highest near the Kaministiquia River and in western Lake Superior; and (3) arsenic concentrations were highest near Silver Bay and in western Lake Superior. Interestingly, surface sediments northeast of Munising, MI, had much higher concentrations of arsenic, copper, mercury, and lead compared to nearby sampling locations. Sediment cores revealed that (1) lead concentrations peaked in the 1950s-1960s, (2) copper concentrations peaked in the 1930s near Isle Royale, and (3) arsenic concentrations peaked in the early 1970s near Duluth-Superior entries.
03:15 PM
New Perspectives on legacy and emerging contaminants in sediments of the Great Lakes (7374)
Primary Presenter: Bridget Ulrich, Natural Resources Research Institute (ulrichb@d.umn.edu)
An interdisciplinary team of scientists at the Natural Resources Research Institute (NRRI) and the Large Lakes Observatory (LLO) at the University of Minnesota Duluth is working to assess relationships between legacy and emerging contaminants, sediment biogeochemical processes, and ecological stressor-response relationships in sediments of the Laurentian Great Lakes. Our overall objective is to advance understanding of the complex and interdependent relationships between environmental distributions of persistent bioaccumulative toxic contaminants (PBTs), biogeochemical cycling in sediments, and overall ecosystem health in the Great Lakes. Sediments will be collected from each of the Great Lakes from 2021 - 2025 at 157 sample stations, including 15 long-term sediment records. A robust suite of chemical, physical, and biological analyses will be performed on sediments, including quantification of trace levels of over 250 legacy and emerging organic contaminants such as polychlorinated biphenyls (PCBs) and poly- and perfluoroalkyl substances (PFAS). The assessment will provide the most comprehensive PBT distribution, biogeochemical, and ecological data set for the Great Lakes to date, transforming our understanding of the underlying factors that affect the overall ecological health of the Great Lakes. Preliminary legacy and emerging organic contaminant data from the 2021 survey of Lake Superior sediment will be presented.
03:30 PM
Seagrass meadows sequester up to half of Pb, Zn and Cd emissions by one of the largest smelters in the world. (6255)
Primary Presenter: Anna Lafratta, Edith Cowan University (a.lafratta@ecu.edu.au)
One of the world’s largest smelters has been operating since 1889 in Port Pirie (South Australia), contaminating the environment and affecting human health. The 110 km2 of seagrass meadows adjacent to the smelting site can act as a sink of this pollution. However, their role as pollution filters and traps remains poorly understood. Here we quantified the magnitude of Pb, Zn and Cd emissions sequestered by Posidonia australis meadows since 1889. The metal pollution record contained within seagrass soil cores sampled across the region showed that smelting operations contaminated the entire area, with decreasing metal sequestration by seagrass with increasing distance from discrete points of contamination. The meadows accumulated a total stock of ~1,300 t of Pb, ~3,450 t of Zn, and ~90 t of Cd since 1889. By comparing the accumulated metal stocks since 1999 with the reported smelter emissions for the same period, we estimated that seagrasses sequestered ~20% of Pb, and ~50% of Zn and Cd cumulative emissions. The findings showed that seagrass can play a significant role as long-term sinks of metal pollution in highly contaminated environments. Conservation efforts should prioritize these seagrass meadows to avoid the potential release of pollutants following habitat loss, which could turn seagrasses from a sink to a source of pollution.
03:45 PM
PHYLOGENETIC AND FUNCTIONAL DIVERSITY OF MICROBIAL GENOMES WITH CAPACITY TO DETOXIFY INORGANIC MERCURY AND METHYLMERCURY (5431)
Primary Presenter: Carla Pereira-Garcia, Universidad Autonoma de Barcelona (carla.pereira@uab.cat)
Methylmercury (MeHg) is one of the most worrisome contaminants nowadays; it is neurotoxic for humans, and it can bioaccumulate and biomagnify through the aquatic food webs. The microbial mer operon contains two enzymes, merA, mercuric reductase and merB organomercurial lyase, responsible for the detoxification of MeHg. We sequenced 30 microbial metagenomes from marine sediments collected from 10 different Hg-impacted sites of three marine regions: Bay of Biscay (Nervión and Suances), the Mediterranean (Barcelona) and Baltic Sea (Köpmalhlmen). We built a Hg-detoxification Reference Gene Catalogue (Hg_RGC) with over 16 million non-redundant genes and applied genome-resolved metagenomics to assemble 583 non-redundant metagenome-assembled genomes (MAGs) of medium and high quality named as MERCLUB Microbial MAGs to evaluate the ecology, metabolic potential and activity of MeHg detoxifying bacteria and archaea. From those, we detected 16 MAGs containing the merA gene and 35 MAGs containing the merB gene. Two MAGs contained both merA and merB genes with almost complete genomes related to Actinomycetales (Microbacterium sp.) and Rhodobacterales. We also recovered MAGs containing merA or merB genes from previously overlooked new phyla such as Krumholzibacteriota, Abyssubacteria or Zixibacteria, Finally, a comprehensive phylogenetic analysis for merA and merB was performed integrating merAB genes from our MERCLUB MAGs, Hg_RGC catalogue and isolates from the same sites to infer their genetic diversity and highlight potential new players involved in Hg detoxification processes.
04:00 PM
Pesticide and methylmercury fluxes to a marine protected region of Australia influenced by agricultural expansion (5271)
Primary Presenter: Melanie TAYLOR, Southern Cross University (meltinicreations@gmail.com)
Blue carbon systems are important estuarine environments that provide a variety of ecological services, including carbon burial and the sequestration of pollutants. However, urban development and anthropogenic activities can impact the ability of these estuarine systems to retain and store pollutants, with unknown consequences for marine communities. Here, we present dated sediment cores from within the Solitarily Island Marine Park, a marine sanctuary in Australia subject to runoff from highly developed catchments. We reveal historical accumulation rates of trace metals and pesticides associated with agricultural activities. Propiconazole and tebuconazole, fungicides highly reactive in marine habitats, were recorded throughout the site nearest the freshwater source. Furthermore, mercury content revealed elevated levels in the most recent sediments, while methylmercury (MeHg) was found to range from 0.1 mg kg-1 in 2017 to 0.2 mg kg-1 in 2019. Additionally, arsenic accumulation rates are shown to have significantly increased from 19.1 mg m-2 year-1 in 1930 to 259.6 mg m-2 year-1 in 2020. These substances were determined to be mostly of terrestrially derived sources, likely related to historical catchment deforestation, as indicated through δ13C and C:N molar ratios. This study highlights the importance in evaluating agriculture-derived pollutant discharge to protected coastal regions, providing a robust dataset that may be used to mitigate pollutant runoff in catchments impacted by expanding activities throughout Australia, and around the globe.
04:15 PM
Trapped – Pesticides in Aquatic Systems Show Same Behaviour in Surface Water and Groundwater (5840)
Primary Presenter: Karin Meinikmann, Julius Kühn-Institute (karin.meinikmann@julius-kuehn.de)
Pond water quality in agricultural landscapes is estimated to reflect surrounding agricultural activities on the local scale. This especially applies to the field-specific application of pesticides which are considered to be mainly transported into aquatic systems by surface runoff and local-scale wind drift. However, there is evidence of many pesticides with ubiquitous occurrences in different aquatic settings, questioning current theories on their transport and fate. This study from North-eastern Germany presents monitoring results of pesticides in agricultural ponds and adjacent shallow groundwater. The results show that individual substances do not only occur simultaneously in both, surface water and groundwater but also follow similar concentration dynamics. This does not only apply to single locations but also to different locations with different land use intensities. Pesticides found comprise substances currently in use, metabolites and legacy compounds. Since for many of the detected substances concentrations are higher in surface water, groundwater exfiltration can be excluded as an advective source for pond pollution. The findings rather demonstrate a similar ubiquitous state of pollution in both, surface and subsurface aquatic environments whose dynamics are driven by a common factor. We suspect the substances are trapped in aquatic systems underlying delayed removal. Furthermore, regional subsurface hydrology may be responsible for temporal occurrences and concentration dynamics of individual substances.
SS110A Contaminant Fate and Transport in Aquatic Systems and Their Interactive Effects on Ecosystem Functioning
Description
Time: 3:00 PM
Date: 5/6/2023
Room: Sala Ibiza A