Hexavalent chromium in house dust- A comparison between an area with historic contamination from chromate production and background locations

摘要

In contrast to Cr~(+3), Cr~(+6) is carcinogenic and allergenic, Although Cr~(+6) can occur naturally, it is thought that most soil Cr~(+6) is anthropogenic, however, the extent of Cr~(+6) in the background environment is unknown. Cr~(+6)-containing chromite ore processing residue (COPR) from chromate manufacture was deposited in numerous locations in Jersey City (JC), New Jersey. In the 1990's, significantly elevated concentrations of total Cr (Cr~(+6) + Cr~(+3)) were found in house dust near COPR sites. We undertook a follow-up study to determine ongoing COPR exposure. We compared Cr~(+6) in house dust in JC to selected background communities with no known sources of Cr~(+6). Samples were collected from living areas, basements and window wells. Cr~(+6) was detected in dust from all JC and background houses. In the JC homes, the mean (± SD) Cr~(+6) concentration for all samples was 3.9 ± 7.0 μg/g (range: non-detect-90.4 μg/g), and the mean Cr~(+6) loading was 5.8±15.7 μg/m~2 (range: non-detect-196.4 μg/m~2). In background homes, the mean Cr~(+6) concentrations of all samples was 4.6 ±7.8 μg/g, (range, 0.05-56.6 μg/g). The mean loading was 10.0±27.9 μg/m~2 (range, 0.22-169.3 μg/m~2). There was no significant difference between Cr~(+6) dust concentrations in Jersey City and background locations. Stratification by sample location within houses and sampling method gave similar results. Samples exceeding 20 μg/g were obtained only from single wood surfaces in different homes. Lower concentrations in window well samples suggests transport from outside is not the major source of indoor Cr~(+6). Landscaping and groundcover may influence indoor Cr~(+6). There appears to be a widespread low level background of Cr~(+6) that is not elevated in Jersey City homes despite its historic COPR contamination. It is possible that house dust, in general, is a source of Cr~(+6) exposure with potential implications for persistence of chromium allergic contact dermatitis.