Chemical contamination assessment of Gulf of Mexico oysters in response to hurricanes Katrina and Rita

Abstract

Hurricane Katrina made landfall on August 29, 2005 and caused widespread devastation along the central Gulf Coast states. Less than a month later Hurricane Rita followed a similar track slightly west of Katrina's. A coordinated multi-agency response followed to collect water, sediment and tissue samples for a variety of chemical, biological and toxicological indicators. The National Oceanic and Atmospheric Administration's National Status and Trends Program (NS&T) participated in this effort by measuring chemical contamination in sediment and oyster tissue as part of the Mussel Watch Program, a long-term monitoring program to assess spatial and temporal trends in a wide range of coastal pollutants. This paper describes results for contaminants measured in oyster tissue collected between September 29 and October 10, 2005 and discusses the results in the context of Mussel Watch and its 20-year record of chemical contamination in the region and the nation. In general, levels of metals in oyster tissue were higher then pre- hurricane levels while organic contaminants were at or near record lows. No contaminant reported here exceeded the FDA action level for food safety.

Assessment of coastal storm impacts on contaminant body burdens of oysters collected from the gulf of Mexico

“…Among the seven contaminants that were found to have increased in oyster tissues, five were heavy metals. This reaffirms the observation that metal body burdens are most likely to increase in oysters after a severe storm (Johnson et al 2009).…”

“…For example, after Hurricane Katrina, chemical analysis of floodwaters revealed that several metals and organic contaminants were in excess of the US Environmental protection Agency (EPA) threshold for human health exposure (Presley et al 2005). Similarly, in tissues of oysters exposed to subsiding storm surge and floodwater after Katrina, significant increases of trace metal concentrations were observed (Johnson et al 2009). These efforts, though localized, resulted in some significant findings that are relevant for an integrated ecosystem impact assessment after severe storms.…”

Tulane Virus as a Potential Surrogate To Mimic Norovirus Behavior in Oysters

“…Improvements in detection methods, increased epidemiological surveillance, and efforts by authorities to improve the quality of products put on the market have contributed to better recognition of viral contamination. These improvements have assisted in identifying that increases in human populations in coastal areas, as well as climate change, inducing heavy rainfall and associated sewage overflows, constitute risk factors for shellfish contamination (3,4).…”

Trace Organic Contaminants (PAHS, PCBs, and Pesticides) in Oysters Crassostrea virginica, from the Caloosahatchee Estuary and Estero Bay, SW Florida.

“…In that context, sedimentary resuspension may have resulted in periodic exposure of the trace organic contaminants in this study. Sediment resuspension events have been demonstrated to result in greater bioaccumulation of metals by oysters in the Gulf of Mexico (JOHNSON et al, 2009). Given that all the sampling collection areas are interidal and shallow-subtidal, oysters from these areas are exposed to sediment re-suspension through wind-and tidal-driven forces as well as boat wakes.…”