Water Resources Research Act Program

Details for Project ID 2008PA85B

Mercury in Pennsylvania Forest Streams: Do Hotspots Exist?

Institute: Pennsylvania
Year Established: 2008 Start Date: 2008-03-01 End Date: 2009-02-28
Total Federal Funds: $20,000 Total Non-Federal Funds: $40,024

Principal Investigators: Elizabeth Boyer, David DeWalle

Project Summary: Mercury is a persistent element in the environment that has the ability to bioaccumulate and biomagnify up the food chain, with potentially harmful effects for human health and ecosystems. Concern for increased environmental Hg levels and effects led to the development of a Mercury Deposition Network (MDN) that is operated by the National Atmospheric Deposition Program, which provides air quality monitoring at sites across the US and southern Canada. Pennsylvania receives among the highest rates of Hg deposition of any location in the northeastern USA, experiencing wet atmospheric deposition rates of 7-10 Hg/m2 in precipitation in 2006. Human exposure to Hg occurs mostly through fish consumption, and currently fish eating advisories due to mercury have been posted for over 877 stream miles and 28 lakes (28,500 acres) across Pennsylvania (Lynch et al. 2005). Stream Hg levels are believed to be a key indicator for concentrations of mercury available for uptake by biological organisms (Morel et al 1998; Hakanson et al 1998; Verta 1990). Very little data are available and few studies have been conducted on Hg levels in stream water, sediment, and fish tissue for Pennsylvania (Brigham et al 2003; Brightbill et al 2004). Recently, researchers in northeastern U.S. (Maine, New Hampshire, Vermont, Massachusetts, Connecticut, and New York) and southeastern Canada (Driscoll et al 2007; Evers et al 2007) found evidence in biota to suggest the presence of hotspots (location with increased Hg deposition) around coal fired power plants. These findings carry with them implications for current federal and state regulation of Hg emissions. Our overall objective is to determine the presence or absence of mercury hotspots around major Hg emission sources in Pennsylvania. We plan to use a synoptic sampling approach; ten emission source sites across Pa with three control (upwind) streams and three experimental (downwind) streams within a 15 mile radius will be studied. Sampling of water, sediment, moss, and fish tissue will occur at each emission source. All samples will be analyzed for total mercury, with selective sampling of water for MeHg (biologically active form). Basic water chemistry will also be determined for correlation with stream Hg levels (Lee et al 1998; Schwesig and Matzner 2001; Shanley et al. 2002, Skylberg et al 2003). Statistical analysis will be conducted using a fractional factorial design for determination of hotspot effects. Results from this study will determine whether halo effects are occurring across the northeastern U.S. and whether deposition impacts are found in stream ecosystems. Identification of the existence or absence of hotspots in Pennsylvania could also aid in regulation of mercury emissions by the PA Department of Environmental Protection.