Sheehan P J, Meyer D M, Sauer M M, Paustenbach D J
A Division of McLaren/Hart, Alameda, California 94501.
J Toxicol Environ Health. 1991 Feb;32(2):161-201. doi: 10.1080/15287399109531476.
Millions of tons of chromite-ore processing residue have been used as fill in various locations in northern New Jersey and elsewhere in the United States. The primary toxicants in the residue are trivalent chromium [Cr(III)] and hexavalent chromium [Cr(VI)]. The hazard posed by Cr(III) is negligible due to its low acute and chronic toxicity. In contrast, Cr(VI) is a human carcinogen following inhalation of high concentrations. It can also cause allergic contact dermatitis. This evaluation addresses a residential site where the arithmetic mean (x) and geometric mean (gm) concentrations of Cr(III) in soil were 2879 and 1212 mg/kg (ppm). The mean and geometric mean concentrations of Cr(VI) were 180 and 4 mg/kg, respectively. The uptake (absorbed dose) of Cr(III) via soil ingestion, consumption of homegrown vegetables, and ingestion of inspired particles was determined. The uptake of Cr(VI) via dermal absorption from contact with surface soil and building wall surfaces, as well as inhalation, was also evaluated. The techniques used in this assessment are applicable for evaluating the human health risks posed by any residential site having contaminated soil. The potential for both sensitized and unsensitized persons to develop allergic contact dermatitis due to exposure to soil contaminated at these levels was found to be negligible. The estimated average daily dose (ADD) via ingestion and dermal absorption for the maximally exposed individual (MEI) was about 1500- and 40-fold below the EPA reference dose (RfD) for Cr(III) and Cr(VI), respectively. It was shown that for residential sites, the most important route of exposure to Cr(III) was incidental soil ingestion. Although not relevant to these sites specifically, if garden vegetables could be successfully grown in these soils, then they would probably be the predominant source of uptake of Cr(III). Since inhalation of Cr(VI)-contaminated dust (but not ingestion or dermal contact) poses a cancer hazard, the doses and associated risks were assessed. The estimated cancer risks for the MEI and most likely exposed individual (MLEI) were approximately 5 x 10(-9) and 2 x 10(-9), respectively. These levels of risk have always been considered well below those that warrant regulatory concern. For persons living on residential properties, the cancer risk due to inhaling suspended particles is likely to be less than 1 in 1,000,000 if Cr(VI) levels in soil are less than 180 mg/kg (ppm). Based on this analysis, the levels of Cr(III) and Cr(VI) at this and similar sites do not pose a health hazard following acute or chronic exposure.
数百万吨铬铁矿加工残渣已被用作填充物，用于新泽西州北部及美国其他地区的各个地点。残渣中的主要有毒物质是三价铬[Cr(III)]和六价铬[Cr(VI)]。由于Cr(III)的急性和慢性毒性较低，其造成的危害可忽略不计。相比之下，吸入高浓度的Cr(VI)是一种人类致癌物。它还会引起过敏性接触性皮炎。本评估针对的是一个居住场所，该场所土壤中Cr(III)的算术平均值(x)和几何平均值(gm)分别为2879和1212毫克/千克(ppm)。Cr(VI)的平均浓度和几何平均浓度分别为180和4毫克/千克。测定了通过土壤摄入、食用自家种植的蔬菜以及吸入空气中的颗粒物对Cr(III)的摄取量(吸收剂量)。还评估了通过与表层土壤和建筑物墙面接触的皮肤吸收以及吸入对Cr(VI)的摄取量。本评估中使用的技术适用于评估任何受污染土壤的居住场所对人类健康造成的风险。发现无论是敏感人群还是非敏感人群，因接触这些水平受污染的土壤而发生过敏性接触性皮炎的可能性都可忽略不计。对于暴露量最大的个体(MEI)，通过摄入和皮肤吸收估计的平均每日剂量(ADD)分别比美国环境保护局(EPA)针对Cr(III)和Cr(VI)的参考剂量(RfD)低约1500倍和40倍。结果表明，对于居住场所，接触Cr(III)的最重要途径是偶然摄入土壤。虽然与这些场所没有特别相关性，但如果这些土壤能够成功种植园圃蔬菜，那么蔬菜可能会成为摄取Cr(III)的主要来源。由于吸入受Cr(VI)污染的粉尘(而非摄入或皮肤接触)会造成癌症风险，因此对剂量和相关风险进行了评估。MEI和最可能暴露个体(MLEI)的估计癌症风险分别约为5×10^(-9)和2×10^(-9)。这些风险水平一直被认为远低于值得监管关注的水平。对于居住在住宅物业中的人来说，如果土壤中Cr(VI)水平低于180毫克/千克(ppm)，因吸入悬浮颗粒物导致的癌症风险可能低于百万分之一。基于此分析，该场所及类似场所的Cr(III)和Cr(VI)水平在急性或慢性暴露后不会对健康造成危害。
