开封市幼儿园地表灰尘重金属积累及健康风险

在开封市采集31个幼儿园的地表灰尘样品,用火焰原子吸收分光光度法(F-AAS)分别测定其＞0.25 mm、0.25～0.15 mm、＜0.15 mm和多粒级混合样品的Pb、Zn、Cr、Cu和Ni含量,应用EF法和HI法探讨了灰尘重金属富集特征和针对幼儿的健康风险.结果表明:灰尘Pb、Zn、Ni、Cu和Cr平均含量分别为...

Accumulation and health risk assessment of heavy metals in kindergarten surface dust in the city of Kaifeng

Samples of surface dust were collected from thirty-one kindergartens in Kaifeng. The concentrations of Pb, Zn, Cr, Cu and Ni in different size-fractionated (<0.15, 0.15~0.25 and >0.25 mm in diameter) samples and in the mixed samples with all size fractions were determined by flame atomic absorption spectrophotometry (F-AAS). The accumulations of heavy metals in dust were analyzed using Enrichment Factor (EF), and health risks of heavy metals to young children were assessed using Health Index (HI). The results show that the average concentrations of Pb, Zn, Ni, Cu and Cr in the samples are 242.99, 297.32, 52.57, 38.92 and 82.13 mg·kg-1 respectively, which all exceed the background values in the fluvo-aquic soils of China. The metals Pb, Zn and Cr, mainly from human activities and enriched in dust significantly, are anthropogenic source metals; Ni, mainly from natural factors, is a natural source metals, while Cu, both from human activities and natural factors, is a mixed source metals. The samples from the old downtown area, industrial area and near major roads are polluted with heavy metals much more heavily than those in other areas of the city. It was also found that Pb is mainly enriched in the coarse fraction (>0.25 mm) of dust, Zn in the fine fraction (<0.15 mm), and Cu, Cr and Ni in all size fractions of dust without significant differences. The particle compositions of dust are fine 55%, coarse 28% and medium 17%, while the average mass percents of all heavy metals in the different size fractions are 50.03% in fine dust, 29.55% in coarse and 18.43% in medium. The main exposure pathway of heavy metals to young children is hand-to-mouth ingestion. The HIs indicate that heavy metals have different levels of health risk to young children (Pb>Cr>Ni>Zn>Cu), in eight (25.8%) kindergartens HIPb>1, and one (3.2%) HICr>1. A health risk from Pb and Cr exists in some kindergartens; but generally, there is no health risk of heavy metals associated with surface dust in most kindergartens in Kaifeng.