Chromium mobility in freshwater wetlands

Summarization: A wetland at a chromium-contaminated electroplating site was studied to determine its ability to immobilize subsurface chromium contamination. First, a site characterization was conducted to determine the lateral and vertical extent of chromium contamination in the sediment and pore water. The wetland was found to be highly contaminated, with sediment concentrations of up to 50,000 μg g−1. Chromium was partitioned largely on the sediment, with Kd's up to 317,000 mL g−1. No Cr(VI) was detected in the pore water. Sequential chemical extractions performed on the sediment found 60–90% of the chromium bound in the Full-size image (<1 K) and residual fractions of the soil, with very little exchangeable or organic-bound chromium present. These results indicate that the chromium is very tightly bound to the sediment. XPS determined a very low Full-size image (