再生水灌溉土壤对蔬菜食用安全的风险性评价

Plant Irrigated by Reclaimed Water and Risk Assessment

DOI：10.3969/j.issn.1673-1689.2015.06.015

中文关键词: 污水 再生水 土壤 蔬菜 富集

英文关键词: sewage, reclaimed water, soil, vegetable, accumulation

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中文摘要:

再生水灌溉是解决水资源短缺的潜在途径之一，关于再生水灌溉条件下土壤中重金属的迁移行为及其对表层土壤的污染风险至今仍缺乏研究。为此，进行了对不同水体浇灌蔬菜的试验研究。相比较污水浇灌和自来水浇灌，再生水灌溉不仅对土壤没有污染，还极大地节约了水资源成本，并为蔬菜提供了大量的生长元素。研究结果表明，再生水浇灌蔬菜长势优于自来水和污水浇灌蔬菜，且浇灌60 d后，再生水中的Cr、Cd、As、Hg、Pb、Ni、Zn和Cu在土壤中虽有一定的富集，但随着淋溶时间的延长， 各种重金属质量分数保持不变；再生水浇灌的土壤在重金属垂直迁移上的质量分数变化也不大，基本呈水平趋势；与土壤环境质量标准（GB15618-1995）相比，再生水浇灌后的土壤重金属没有额外超标，优于蔬菜种植的土壤标准要求。风险综合评价等级为可承受（一级）风险。

英文摘要:

Reclaimed water irrigation is a potential alternate source of water to help meet water shortages. There are few studies focus on the migration of heavy metals in soil and the topsoil contamination when reclaimed water is used for irrigation. The irrigation on vegetables using reclaimed water from different sources was studied. Reclaimed water irrigation didn't cause soil contamination and conserved fresh water resources comparing with sewage irrigation and tap water irrigation, at the meanwhile, it also could provide large amounts of nutrients for vegetables. The growth of vegetable irrigated by reclaimed water was better than those using tap water or sewage. The heavy metal accumulation in soil was observed after 60 days including Cr, Cd, As, Hg, Pb, Ni, Zn and Cu, which was low in concentration and stayed stable within irrigation duration. The vertical distribution of heavy metals in soil also changed little, with trends staying intact. The heavy metal content in soil was lower than the value in the soil environment quality standard (GB15618-1995), and better than the soil quality standard of vegetable planting. Risk assessment is within the generally acceptable risk range (a).

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