土壤中铜的生物可给性及其对人体的健康风险评价

为了研究土壤中铜的生物可给性与土壤理化性质之间的相互关系以及人体无意摄入土壤铜的风险,采集我国一些地区的15个土壤样品,利用in vitro方法研究了这些土壤中铜的生物可给性及其对人体的健康风险。结果表明,有2个土壤样品中铜的含量高过我国土壤环境质量标准的三级标准,有8个土壤样品中铜的含量高过二级标准;土壤中铜的溶解态浓度及其生物可给性变化很大,胃肠阶段铜的溶解态含量分别为5.2~308.8 mg·kg~(-1)和5.9~348.5 mg·kg~(-1),平均值分别为74.8 mg·kg~(-1)和82.0 mg·kg~(-1);而铜的生物可给性分别为183%~66.6%和213%~77.4%,平均值分别为442%和51.1%。胃阶段铜的生物可给性与土壤有机质和pH呈显著正相关,而与粘粒呈显著负相关,与铁铝氧化物有显著相关性;小肠阶段铜的生物可给性与土壤有机质和pH呈显著正相关,与土壤中总铜和锰氧化物含量呈显著负相关。如以胃阶段为判断,无意摄人土壤中铜对儿童的TDI(tolerable daily intake)贡献率除浙江富阳为2.51%外,有12个土壤样品低于1.00%,最低为0.11%。如以小肠阶段为判断,无意摄入土壤中铜对儿童的TDI贡献率除浙江富阳和浙江台州的土壤分别为2.83%和2.01%,另有12个土壤样品低于1.00%。可见,对于本研究中大多数土壤,通过口部无意摄入土壤中铜的对人体并没有很高的风险。

Bioaccessibility of Soil Copper and Its Health Risk Assessment

Fifteen soil samples were collected from typical sites in China to study the bioaccessibility of soil copper (Cu) based on the PBET (physiologically based extraction test) method. The relationship between the soil properties and the bioaccessibility as well as the health risk assessment of the oral ingestion soil was also investigated. The results showed that comparing with Chinese environmental quality standard for soils, the concentrations of Cu in two soil samples were higher than the third standard (<400 mg·kg^-1) and the concentrations in eight soil samples exceeded the secondary standard (<50 mg·kg^-1, pH<6.5; <100 mg·kg^-1, 6.5 < pH < 7.5; <100 mg·kg^-1, pH >7.5). The high variability of dissolved and bioaccessible Cu of soils were observed. The concentrations of bioaccessible Cu ranged from 5.2-308.8 mg·kg^-1 with a mean of 74.8 mg·kg^-1 in the gastric phase and 5.9-348.5 mg·kg^-1 with a mean of 82.0 mg·kg^-1in the small intestinal phase. The Cu bioaccessibility ranged from 18.3%-66.6% with a mean of 44.2% in the gastric phase and 21.3%-77.4% with a mean of 51.1% in the small intestinal phase. The significant positive correlations between the Cu bioaccessibility with soil pH, organic matter were observed in the gastrointestinal phase. The negative correlations with clay in the gastric phase and with the concentrations of Cu and Mn-oxide in the small intestinal phase were observed. For children, the highest contribution of the oral ingestion soil Cu to the tolerable daily intake (TDI) that estimated by WHO was 2.51% in the gastric phase and 2.83% in the small intestinal phase, but the contribution rate of 12 soil samples was lower than 1.00% in the gastrointestinal phase. The health risk from the oral ingestion of soil Cu was low in most of collected soil samples.