Background air concentrations of Cr(VI) in Hudson County, New Jersey: implications for setting health-based standards for Cr(VI) in soil.

An accurate measure of "background" airborne Cr(VI) concentrations will be necessary to derive site-specific health-based Cr(VI) soil concentrations at sites containing chromite ore processing residues (COPR) in Hudson County, NJ. To date, no such data have been collected in New Jersey. This paper describes an air sampling program designed to measure background concentrations of Cr(VI) in Hudson County and compare those concentrations with the air sampling results obtained previously at 30 COPR sites in Hudson County. Background airborne Cr(VI) concentrations ranged from 0.2 to 3.8 ng/m3 with an arithmetic mean of 1.2 ng/m3. Comparisons of the airborne Cr(VI) concentrations previously measured at 30 COPR sites indicated that more than two-thirds of the sites had mean airborne Cr(VI) concentrations that were not statistically significantly greater than background. Our findings suggest that, in general, vehicle disturbance is required for significant soil suspension to occur at these sites. Since airborne Cr(VI) concentrations at many of these sites are close to background, it is critical that background airborne Cr(VI) levels be considered when deriving health-based soil standards at the COPR sites.