Survey of Nonpoint Trace Metal Inputs to Lake Lanier
Leigh, David S.
Gamble, Douglas W.
MetadataShow full item record
In order to explore the possibility of anomalously high trace metal contributions to Lake Lanier, sediment and water samples from the watershed and lake were analyzed for toxic trace metals (USEPA "priority pollutants"). Sediment samples were collected from the mouths of 50 tributary streams and from 83 other sites, including lake bottom, stream beds and banks, and soils in the watershed. Water samples were collected from 18 tributary mouths during three flow events, including baseflow, low runoff, and moderate runoff flows. None of the sediment sites contained metal concentrations at "hazardous" levels and only a few sites contained metal concentrations that were marginally above NOAA's conservative "lowest effect level" for metals in aquatic sediment. None of the water samples exceeded USEPA drinking water standards, but several samples slightly exceeded the Georgia EPD instream water criteria for mercury (Hg) and lead (Pb). Former gold mines are possible sources for Hg, and urban areas were recognized as contributors of Hg and Pb. In general, the Lake Lanier watershed is relatively clean in terms of trace metals, with a few urban and formerly mined areas contributing metals that exceed the natural background levels.