Characterizing Solubility

Participants

MRRI, Rutgers Univesity-Newark

Problem

Chromite ore processing residue occurs at over 130 sites in Hudson County, New Jersey. Many of these sites are in urban residential areas. This waste is a result of 70 years of chromate and bichromate chemical manufacturing. Between 1905 and 1976, Chromite ore containing 45-50% chromium was shipped from all over the world to plants in Jersey City and Kearny. The discarded residue containing 2-7% chromium (2-3 million tons) was disposed of in a variety of ways from use as fill material, use in construction and to fill wetlands. The environmental impacts of chromium ore disposal are not well known and depend largely on its valence state. Cr(VI) (bichromate and chromate) are relatively soluble and toxic to plants and animals (carcinogenic and mutagenic). Cr(III) on the other hand is relatively non toxic and immobile.

Objectives

Characterize the solubility and speciation of chromium in wetland sediments that were affected by ore residue disposal and evaluate how Cr speciation is linked to the physico-chemical characteristics of the sediments and how to reduce its negative impacts on wildlife.

Strategy

Use a 5-step sequential extraction along with Bulk X-ray absorption spectroscopy and micro XAS analysis using a synchrotron to determine the exact Cr species under several sediment conditions.

Activities

Determine sampling sites from historical records
Collect 10-15 samples from high Chromium sites
Analyze samples for total metal content
Cr species determination through Spectroscopy analysis
Write report and papers with findings and recommendations