Session Title:
Session Leader:
Pollution, Contaminants and Water Quality I
Gib Chase
Presenter:
Presentation:
Clayton McCoy
Groundwater Discharge in the Coastal Zone: Quantification Methods and
Contributions to Nearshore Geochemical Budgets
cam0928@ecu.edu
Email:
Abstract:
The continental shelf of Louisiana often experiences hypoxic conditions in summer months due to
nutrient loading generally accepted as a product of landscape changes and land use practices within
the Mississippi River watershed. Action plans to reduce nutrient loading and long term monitoring
plans do not address the potential source of nutrients delivered to the continental shelf via
groundwater discharge. The neglect of this potential source of nutrients could hamper long term
progress and complicate strategic plans aimed at reducing hypoxic conditions in the region. Over the
past decade, submarine groundwater discharge (SGD) in the coastal zone has become a topic of
interest among the scientific community. SGD can occur anywhere an aquifer is hydraulically
connected to the ocean and is discharged to the water column via nearshore seepage, seepage
through a confining unit, or submarine spring. Considering groundwater is typically elevated in
nutrients relative to surface water, SGD could be a substantial and overlooked component of
nearshore geochemical budgets. This presentation reports the results of a project to determine SGD
rates along the continental shelf of Louisiana using radon as a geochemical tracer of groundwater.
Analysis of the data suggests that topography driven groundwater discharge is not a significant
contributor to the geochemical budget of the region although previous research indicates SGD could
contribute upwards of 40% of that which is discharged from the Mississippi. Management implications
of SGD in the coastal zone include accurate assessment of discharge and potential inclusion of
coastal nutrient budgets.
Presenter:
Presentation:
Email:
Abstract:
Gunnar Lauenstein
Characterizing the Magnitude and Extent of Coastal Contamination Associated
with Hurricanes Katrina and Rita
gunnar.lauenstein@noaa.gov
The EPA, NOAA, FDA, and USGS are coordinating an environmental impact assessment of
Hurricanes Katrina and Rita to characterize the magnitude and extent of coastal contamination and
ecological effects from these storms. This talk provides an overview of efforts to characterize the fate
and composition of the runoff from the hurricane events and to collect samples to assess the risk to
seafood safety, focusing on the NOAA National Status and Trends Program Mussel Watch Project
Contaminant Monitoring (Mussel Watch). Mussel Watch’s 20-year time series for over 120
contaminants in mussels from over 300 sites nationwide provides a long-term baseline for
contaminant levels in the affected region. Two NOAA cruises (Sept. 13-16 and Sept. 24-Oct. 4)
collected data to assess whether contaminant signatures from Katrina are significantly different from
historic levels, and from neighboring regions. Scientists collected and analyzed sediment and oyster
tissue samples for a standard suite of analytes, including conventional pesticides, metals, PAHs, and
PCBs. Toxicity tests (Microtox and P450 assays) were conducted on the sediment samples.
Sediment samples were also analyzed for concentrations of polybrominated flame retardants, the
insecticide Fipronil, and Clostridium perfringens, a pathogenic microorganism widely distributed in the
environment where spores of the organism persist in soil, sediments, and areas subject to human or
animal fecal pollution. Water samples were analyzed for the triazine herbicide Atrazine, and for
additional bacterial and viral indicators of fecal contamination. Preliminary results will be presented.
Presenter:
Presentation:
Email:
Abstract:
Ruth Kelty
Minimizing Human Health and Ecological Risks Posed by Mercury
Contamination in the Gulf of Mexico
ruth.kelty@noaa.gov
The significant risk of mercury to human and ecosystem health constitutes a major resource
management issue. The most common route of mercury exposure is ingesting mercury in fish and
other seafood. Survey data have indicated that at least 300,000 U.S. newborns per year are exposed
in utero to sufficient mercury placing them at risk of neurological diminishment (e.g., lower IQ). In
2004, EPA and FDA issued an advisory about fish consumption for women who might become
pregnant, women who are pregnant, nursing mothers, and young children. Since mercury travels in a
complex manner from power plants and other atmospheric sources through ecosystems and food
chains, progress in implementing protective measures or management strategies has been
hampered by a general lack of cohesive, inter-disciplinary knowledge, particularly of the inputs,
occurrence, transformations, cycling, and food chain transfer in the coastal and marine waters.
Stakeholders are demanding that health risks and economic impacts to fishing interests be reduced.
In response, NOAA scientists are coordinating research programs to develop scientific information
and tools for use in minimizing human health and ecological risks posed by mercury contamination.
This talk will provide an overview of their approach, from monitoring mercury concentrations to
determining mercury source, fate, and cycling to characterizing human health and ecological risk, to
improving outreach to reduce those risks. Current efforts focus on the Gulf of Mexico, future work
may build on long-term research in the Florida Everglades and importance of wetlands in the
accumulation and food web-transfer in aquatic systems.