PDF《征与源分析》

475004 2. Henan Open Laboratory for Key Subjects of Environmental Change and Water?Soil Pollution Control, Henan University, Kaifeng

475004 3. Environmental Emergency and Accident Command Center of Zhengzhou, Zhengzhou

450007 Received

9 June 2015;

received in revised form

29 July 2015;

accepted

29 July

2015 Abstract: Understanding spatial distribution and identifying heavy metal sources in agricultural soils are crucial for farmland maintenance, ecosystem health, and land use planning in a peri?urban area. Samples of topsoils ( n = 259) were collected from a peri?urban area in Henan province using a

200 m*200 m grid method. The concentrations of Cd, Zn, Cu, Pb, Ni and Cr in soils were determined by ICP?MS. Spatial distribution and source analysis of heavy metals were conducted using inverse distance weighting (IDW) interpolation combined with Tessier′s speciation extraction method. The 环境科学学报36 卷results show that: 1) the concentrations of Cd, Zn, Cu and Pb varied within the sampling sites, and obviously higher than concentrations in the control area, and 2) there are clearly higher concentrations of heavy metals near the chemical plants and sewage river. These are the primary sources of heavy metals that lead to farmland pollution due to sewage irrigation, side infiltration by the sewage river water, and via a coupling effect with particles emitted from the chemical plants. Heavy metals (Cd, Zn, Pb and Cu) have higher activity and bioavailability due to higher proportion of non?residual forms, suggesting potential health risks are likely in these areas. However, no apparent heavy metal accumulation from the power plant or railway occurred in farmland soils. Besides, heavy metals mainly exist in stable forms within soils which suggests a lower potential health risk. Also, as an agricultural source, the application and amount of chemical fertilizer may affect the spatial variability of heavy metals in soils. Keywords: peri?urban area;

IDW interpolation;

total contents;

chemical fractions;

source analysis

1 引言(Introduction) 改革开放以来,中国的大中小城市均发生了巨 大的转变.特别是进入

21 世纪之后,城市化逐渐进 入了全新的城市化郊区阶段.这种 郊区化 扩散现 象使得城市与郊区之间的作用及交互影响日趋明 显,形成了城郊工、农业以及交通与城市生活复合 污染区,因而城乡交错区重金属污染问题日益受到 关注.很多学者对城乡交错区土壤环境质量开展了 针对性的研究.如2001 年赵杰等(2001)就开始关注 开封市城乡结合部土壤生产质量及其动态变化.郑 海龙等(2006) 为揭示城市边缘带强烈人为活动对 土壤环境质量的影响,分析了上海梅山钢铁集团附 近区域土壤重金属含量空间分布特征及污染现状. 徐勇贤等(2007) 以经济高速发展的长三角地带的 南京和无锡两个城乡交错区为例,开展了城乡交错 区土 壤重金属平衡及生态效应研究. Kapungwe (2013)研究了赞比亚城乡交错区受污水灌溉农场 中水-土壤-作物系统中重金属的污染状况.付传城 等(2014)以南京市溧水区柘塘镇为例,就表层土壤 中重金属的总量、时空变化特征及来源进行了研究. 然而,综合来看,现有研究仍多停留在对城乡交错 区重金属总量污染现状的分析上,或是局限于某一 局部环境区域的研究,尚缺乏对城乡交错区土壤中 重金属总量、形态的空间分布特征及复杂性来源的 系统解析.重金属的形态直接关系到其生物有效性 与健康风险,而如何清楚辨析复杂土壤环境中重金 属的来源特征,能够为有效防治重金属的潜在健康 危害,合理开展农业环境污染治理和土地利用管理 工作提供科学依据. 基于 GIS 的地统计学分析技术被广泛地应用于 土壤重金属空间分布特征及其变异规律分析中,其 有效 弥补了传统研究方法的不足. 如胡克林等(2004)采用 Kriging 最优内插法获取了北京市大兴 区表层土壤重金属含量的空间分布特征. Maas 等(2010)采用