Toxics/Mercury Studies
Overview
Toxics, including heavy metals like mercury accumulate in the tissue of organisms and may alter key ecosystem processes.
"Air toxics" or airborne contaminants (such as persistent organic pollutants – POPs and heavy metals) have the potential to cause ecosystem impairment in national parks, because the compounds are long-lasting, can accumulate in biological tissue of organisms, and may alter key ecosystem processes.
The National Park Service began a coordinated effort in 2002 to understand bioaccumulation of toxics to NPS areas, and developed a strategy for an air toxics monitoring network in the western U.S. and Alaska, the Western Airborne Contaminants Assessment Project (WACAP). The geographic focus on the west was based on concerns over trans-Pacific transport and accumulation of these toxics in Arctic, near-Arctic, and mid-latitude mountain snowpacks. In addition, monitoring of air toxics such as dioxin and mercury has been ongoing in a few selected parks in the eastern U.S. for several years.
The studies described below represent several of the recent and current airborne toxics and mercury projects initiated by the National Park Service.
Western Airborne Contaminants Assessment Project (WACAP):
The Western Airborne Contaminants Assessment Project (WACAP) was initiated by the NPS in 2002. Sampling continued through 2007 and the final report, "The Fate, Transport, and Ecological Impacts of Airborne Contaminants in Western National Parks (USA)", was released in 2008. The objective of the 6 year project was to inventory airborne contaminants in national park ecosystems using a network of sites in parks of the western US to provide spatially extensive, site specific, and temporally resolved information regarding the exposure, accumulation, and impacts of airborne toxic compounds. NPS is concerned about airborne contaminants because they can pose serious health threats to wildlife and humans, as some of these compounds tend to bioaccumulate in the food chain. EPA, USGS, US Forest Service, University of Washington, and Oregon State University worked with the NPS on this assessment. Dr. Dixon Landers, an EPA scientist, led the project. Snow, lake water, sediment, vegetation, fish, and moose meat were sampled in 8 western parks over the life of this project.
Compilation and Synthesis of Atmospheric Deposition Rates, Spatial Distribution and Temporal Variations of Selected Heavy Metals and Persistent Organic Pollutants for Gulf Coast Network Parks:
This project locates, compiles, and synthesizes heavy metals and persistent organic pollutants (POPs) data collected in parks in the NPS Gulf Coast Network, to assess concentrations and documented and potential impacts of these metals on natural resources in the parks. The Gulf Coast Network consists of eight NPS units in Alabama, Florida, Louisiana, Mississippi, Tennessee and Texas. The contamination of natural systems by heavy metals and POPs has potentially severe toxicological consequences for living organisms, including humans. The results of this study will be used to identify and prioritize long-term monitoring needs for heavy metals and POPs in these parks. This study targets selected compounds with the ability to impact biological systems, such as: V, Cu, As, Se, Cd, Hg, Pb, DDT series, HCH, HCB, chlordanes, PAHs, PCBs, chlorinated dioxins and furans, current-use pesticides, and polybrominated compounds. The project was initiated in 2003. Dr. Jean-Claude Bonzongo, and Dr. Joseph J. Delfino from the University of Florida are conducted this project. The final report was completed in 2005. A database, containing all organic pollutants and heavy metals found in all Gulf Coast Network parks, is available. It has a convenient search function and can create summary reports by park or pollutant. Contact us for a CD copy of this very useful Microsoft Access 2002 database (267 mb).
Influence of Sediment Microbial Community Structure on Mercury Methylation at Congaree National Park, Hopkins South Carolina:
Surface waters at Congaree National Park are acidic, humic-enriched, and wetland-influenced, making them characteristic of a mercury-sensitive ecosystem. This bottomland ecosystem provides unique habitat that supports a diverse biological population. The South Carolina Department of Health and Environmental Control (SCDHEC) has issued fish-consumption advisories on 36 South Carolina rivers and streams and 17 lakes because mercury levels in the fish exceed the level that is considered safe for humans. The Congaree River has one such advisory. Methylated forms of mercury serve as potent neurotoxins that affect the health of aquatic biota, wildlife, and humans. This project, initiated in 2005, will develop an understanding of the microbial controls that link atmospheric-derived mercury deposited in Congaree National Park to the formation of methylmercury in park ecosystems. Celeste Journey at U.S. Geological Survey is the principal investigator.