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应用生态学报 ›› 2016, Vol. 27 ›› Issue (5): 1468-1478.doi: 10.13287/j.1001-9332.201605.009

• 目次 • 上一篇    下一篇

贵州兴仁煤矿区农田土壤重金属化学形态及风险评估

庞文品, 秦樊鑫*, 吕亚超, 李英菊, 李 刚, 李新丽   

  1. 贵州师范大学贵州省山地环境信息系统与生态环境保护重点实验室, 贵阳 550001
  • 收稿日期:2015-09-24 出版日期:2016-05-18 发布日期:2016-05-18
  • 通讯作者: qinfanxin@126.com
  • 作者简介:庞文品, 男, 1988年生, 硕士研究生. 主要从事环境化学研究. E-mail: pangwenpin@163.com
  • 基金资助:
    本文由国家自然科学基金项目(21467005)资助

Chemical speciations of heavy metals and their risk assessment in agricultural soils in a coal mining area from Xingren County, Guizhou Province, China.

PANG Wen-pin, QIN Fan-xin*, LYU Ya-chao, LI Ying-ju, LI Gang, LI Xin-li   

  1. Guizhou Provincial Key Laboratory for Information System of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, China
  • Received:2015-09-24 Online:2016-05-18 Published:2016-05-18

摘要: 为了解煤矿区周边农田土壤重金属污染状况,采集了贵州省兴仁县某典型煤矿区农田土壤样品64份,测定了土样中重金属(As、Cr、Pb、Zn、Cd、Hg、Cu、Ni)总量及各形态含量,采用单因子指数法、潜在生态风险指数法(Hkanson法)和风险评估编码法(RAC)对研究区主要土壤利用类型(水稻土、薏米地、植烟土和菜园土)中重金属进行潜在生态风险评估和环境风险评价.结果表明: 不同利用类型土壤中重金属含量除Zn外,其他元素均明显超过贵州省背景值.单因子指数法评价结果表明,As、Pb、Hg和Cu污染较为严重,均属重度污染.形态分析表明,土壤中重金属形态构成差异明显,酸可提取态As、酸可提取态Cd所占比例较高;Cr、Zn、Cu、Ni主要以残渣态为主;Pb主要以可还原态和残渣态为主;而Hg的酸可提取态、可还原态、可氧化态均占有相当比例,三者之和大于55%.重金属可利用度大小顺序为:As(63.6%)>Hg(57.3%)>Cd(56.4%)>Pb(52.5%)>Cu(45.7%)>Zn(32.8%)>Ni(26.2%)>Cr(13.2%).潜在生态风险指数表明,各类型土壤潜在生态风险(RI)〖JP2〗为:菜园土(505.19)>薏米地(486.06)>植烟土(475.33)>水稻土(446.86),均处于较高风险.风险评估编码法结果显示,As在水稻土、薏米地及植烟土中均处于高风险,在菜园土中处于中等风险;Cd、Hg均处于中等风险,Cr、Pb、Zn、Cu和Ni均处于低风险.因此,对该区域农田土壤进行管控时应重点考虑As、Cd和Hg污染.

Abstract: In this study, total concentrations and chemical speciations of heavy metals (As, Cr, Pb, Zn, Cd, Hg, Cu and Ni) in 64 agricultural soil samples were determined to evaluate the level of contamination from a coal mining area in Xingren County, Guizhou Province. The single factor index, the Hkanson potential ecological risk index and the risk assessment code (RAC) were used for the evaluation of potential ecological and environmental risks in four main utilized types of soils (paddy soil, Coix lacryma-jobi soil, tobacco-growing soil and vegetable soil). The results demonstrated that the concentrations of heavy metals were significantly higher than their soil background values in Guizhou Province, with the exception of Zn. According to the evaluation results of the single factor index method, the soils were severely contaminated with As, Pb, Hg and Cu. And the chemical speciations of heavy metals significantly varied among the different utilized types of soils. As and Cd mainly existed in acid soluble fraction. Cr, Zn, Cu and Ni mainly existed in residual fraction. The existence of Pb was mainly in reducible fraction and residual fraction. And the content of Hg was distributed mainly in acid soluble fraction, reducible fraction and oxidizable fraction which accounted for about 55% of the total concentration. The bioavailability of heavy metals was characterized by the order of As(63.6%) > Hg(57.3%) > Cd(56.4%) > Pb(52.5%) > Cu (45.7%) > Zn (32.8%) > Ni (26.2%) > Cr (13.2%). The Hkanson potential ecological risk index (RI) suggested that the heavy metals were at considerable ecological risk and the ranking order was vegetable soil (505.19) > C. lacryma-jobi soil (486.06) > tobacco-growing soil〖JP2〗(475.33) > paddy soil (446.86). The risk assessment code (RAC) indicated that As was at high risk in the paddy soils, C. lacryma-jobi soils and tobacco-growing soils, while As was at medium risk in the vegetable soils. Cd and Hg were at medium risk, Cr, Pb, Zn, Cu and Ni were at low risk. Therefore, management measures must be taken to control contamination of As, Cd and Hg in this area.