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/m² (range: non-detect–196.4 μg/m²). In background homes, the mean Cr^{+ 6} concentrations of all samples was 4.6±7.8 μ μg/g, (range, 0.05–56.6 μg/g). The mean loading was 10.0±27.9 μg/m² (range, 0.22–169.3 μg/m²). 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.