Abstract: Between 1905 and 1976, chromite ore containing 45-50% chromium (Cr) was shipped from all over the world to plants in Jersey City and Kearny for chromate and bichromate chemical manufacturing. An estimated 2.75 million tons of chromite ore processing residue (COPR) containing 2-7% chromium was produced in this time period and was widely used as wetland backfill and foundation material throughout Northern New Jersey. More than 130 chromite ore processing residue dumpsites have been identified in Hudson County, many of which are located in urban residential areas. The environmental impacts of COPR are not well understood. Of concern is the presence in COPR of hexavalent Cr(VI), which is a strong carcinogen and mutagen; trivalent Cr(III), in contrast, is much less toxic and mobile. The research presented here characterized the chemical speciation of Cr in samples taken from a COPR dumpsite in the New Jersey Meadowlands, using a combination of chemical extraction experiments and synchrotron-based spectroscopic analyses. The Cr content in the < 1 mm size fraction of the samples ranged between 200 to 850 mg Cr kg-1. The spectroscopic data indicate that Cr is in the trivalent oxidation state, with no evidence to suggest the presence of hexavalent Cr. The extraction data and spectroscopic measurements identified two major Cr species in these samples, which varied in importance depending on sample location. This talk will present and discuss the results from this study in detail, and outline the implications of the findings for the Cr geochemistry at the site.

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