DISTRIBUTION OF PB BETWEEN SEDIMENTS AND PORE WATER IN WOODS LAKE, ADIRONDACK-STATE-PARK, NEW-YORK, USA

Interstitial water samples and sediments were collected from acidified Woods Lake (pH = 5.0) to evaluate Pb profile stability and distribution between the solid and aqueous phases. A simple equation was developed to describe the distribution coefficient for Pb (Kd(Pb)), based on the sample moisture content and analyte concentrations in bulk sediment and pore water. In Woods Lake sediment Kd(Pb) values ranged from 6.7 x 10(4) to 6.7 x 10(5) ml/g. The affinity of Pb for the solid phase was further demonstrated by inverting a sediment core and leaving it for 10 months in situ. Upon retrieval, the Pb profile was found to have remained intact over the same depth, albeit inverted, as in the surrounding sediment. Geochemical modeling using MINTEQA2 demonstrates that Pb solids that may reasonably be expected to precipitate were all undersaturated by several orders of magnitude with respect to the interstitial water, indicating that Pb was sorbed to, rather than precipitated in, Woods Lake sediment.