Trace metal contamination of waters, sediments, and organisms of the Swan Lake area of Galveston Bay

Trace metal concentrations in water, sediments, and organisms (including oysters, shrimp, fish, and Spartina) were determined in the Swan Lake area of Galveston Bay (Wah Chang Ditch). Sediments and organisms were analyzed for total Ag, Al, As, Cd, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn, and Zn; water samples were analyzed for Cd, Cu, Fe, Mn, and Sn. Sediment pollution was likely provided by waste disposal and airborne inputs from a local industrial waste disposal facility. Swan Lake sediments showed higher levels of trace metals relative to Galveston Bay and other Texas bay sediments. Oysters collected in the Swan Lake area contained higher levels of trace metals than snails, and snails contained higher levels than crabs. Crabs in turn contained higher levels than shrimp, while shrimp were greater than fish. Overall, the metal concentrations in Wah Chang Ditch were elevated relative to the Brazos River and Galveston Bay.