Mercury distribution in the sediments of the South River, Virginia

Abstract

A study was undertaken to determine the distribution of mercury in the sediments of the South River for 16 km. below a synthetic fibers plant in Waynesboro, Virginia, which discharged mercury to the river system from 1929 to 1950. The downstream distribution was examined by comparing the results of total mercury analyses on core samples collected at three downstream stations with that obtained from a control station located upstream of the plant. The highest concentration of mercury appeared to be at the Station located 8.5 km downstream of the source. The distribution of mercury across the stream was determined by comparing the mercury values obtained across a four-point transect at each sampling station. The higher mercury concentrations appeared on the east bank and west of mid-stream points of the transect, indicating that future sampling may require only one sample from each bank.

The mercury distribution with core depth was analyzed by segmenting a second set of core samples into 2.5 cm. increments. The mercury was more concentrated at mid-depth of the sediments (10.2 to 15.2 cm.) than at the top or bottom layers of the sediments.

The fine sediments (<0.250 mm) were also analyzed for percent organic carbon, methyl mercury concentrations, and particle size distribution. There appeared to be a positive correlation between mercury concentration and percent organic carbon at Stations 1 and 2. However, a similar correlation was not observed at Station 3.