郑汴路路旁土壤-小麦系统重金属积累及其健康风险评价

HEAVY METAL ACCUMULATION AND HEALTH RISK ASSESSMENT IN THE ROADSIDE SOIL-WHEAT SYSTEM ALONG ZHENGZHOU-KAIFENG HIGH-WAY, CHINA

按离路基不同距离采集土壤、麦苗和籽粒样品,在测定样品重金属(Pb、Cd、Zn、Cr和Cu)的基础上,开展了路旁土壤-小麦系统重金属分布、积累和污染状况分析,并对膳食小麦(Triticumaestivum)引起的健康风险进行了评价。结果表明:1)土壤-小麦系统重金属含量随着离开路基距离的增加呈先增加后减少的趋势,土壤重金属含量>麦苗重金属含量>籽粒重金属含量。2)麦苗和小麦籽粒对土壤重金属富集能力的大小顺序均为Cu>Cd>Zn>Pb>Cr,麦苗对重金属的富集能力大于小麦籽粒。3)膳食小麦所致的Cd个人健康风险较大。

Aim Roadside soils can be polluted by heavy metals from traffic exhaust. These heavy metals can be absorbed by plants, pass through food chains and ultimately harm humans. Our objectives were to investigate spatial distribution, accumulation and contamination of heavy metals （Pb, Cd, Zn, Cr and Cu） in a roadside soil-wheat system and assess the health risk of heavy metals for persons eating the wheat. Methods We collected samples of soils, wheat seedlings and wheat seeds at different distances from the road edge in the Putian section of Zhengzhou-Kaifeng highway. Soil samples were digested with HCI-HNO3-HF-HClO4. Plant samples were digested with a dry incineration method for Cu, Zn and Cr and the HNO3-HClO4 method for Pb and Cd. Cr, Cu, and Zn in soil and plants were determined by flame atomic absorption spectrometry, while Pb and Cd were determined by graphite furnace atomic absorption spectrometry. Important findings Heavy metal concentrations in the samples initially increase and then decrease with the distance from the road. Concentrations in soils are higher than that in wheat seedlings, and the concentrations in wheat seedlings are higher than that in wheat seeds. The enrichment coefficient order of heavy metals in wheat seeds and seedlings is Cu〉Cd 〉Zn〉Pb〉Cr, and the coefficients of the seedlings are higher than those of the seeds. The cadmium health risk of eating wheat seeds is critical, but there are no health risks from copper, lead and zinc in all samples.