The identification of 'hotspots' of heavy metal pollution in soil-rice systems at a regional scale in eastern China
The identification of 'hotspots' of heavy metal pollution in soil-rice systems at a regional scale in eastern China
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DOI：
10.1016/j.scitotenv.2013.11.046
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发表时间：
2014-02-15
影响因子：
9.8
通讯作者：
Brookes, Philip C.
中科院分区：
文献类型：
--
作者：
Li, Wanlu;Xu, Binbin;Brookes, Philip C.
中国农业土壤和农作物正遭受越来越多的重金属破坏，重金属来自各种污染源，包括农业、交通、采矿，特别是蓬勃发展的私人金属回收行业。本研究在浙江温岭采集了219对水稻籽粒和相应的土壤样品，以确定土壤水稻系统中Cd、Cu、Ni和Zn的空间分布关系和污染热点。土壤重金属Cd平均含量为0.316 mg kg(-1)，Cu473 mg kg(-1)，Ni 31.7mgkg(-1)，Z131 mg kg(-1)；稻米中Cd含量为0.132 mg kg-1，Cu2.46mgkg-1，Ni223mgkg-1，Z17.4mgkg-1。土壤Cd、Cd和水稻Cd的变异系数分别为147%、146%和180%，具有较大的变异性。其他金属的变异系数在23.4%~84.3%之间，变异性适中。克里格插值法和当地Moran‘s I指数检测到了这四种金属的污染热点位置。Cd和Cu的空间格局非常相似，污染热点同时位于研究区的西北部，土壤锌在北部有明显的污染热点，而土壤镍在东北部有明显的污染热点。热点的存在可能是工业化和其他人为活动造成的。采用富集指数(EI)来衡量水稻对重金属的吸收。结果表明，土壤-水稻系统中重金属的积累和有效性既受土壤重金属浓度的影响，又受土壤理化性质的影响。交叉相关图定量地表明，EIS与土壤性质显著相关。土壤pH和有机质是控制水稻吸收重金属的最重要因素。因此，在有毒金属污染最严重的温岭地区，应考虑采取积极措施控制土壤污染，减少对食物链的金属污染。(C)2013爱思唯尔B.V.保留所有权利。
Chinese agricultural soils and crops are suffering from increasing damage from heavy metals, which are introduced from various pollution sources including agriculture, traffic, mining and especially the flourishing private metal recycling industry. In this study, 219 pairs of rice grain and corresponding soil samples were collected from Wenling in Zhejiang Province to identify the spatial relationship and pollution hotspots of Cd, Cu, Ni and Zn in the soil rice system. The mean soil concentrations of heavy metals were 0.316 mg kg(-1) for Cd, 473 mg kg(-1) for Cu, 31.7 mg kg(-1) for Ni and 131 mg kg(-1) for Zn, and the metal concentrations in rice grain were 0.132 mg kg(-1) for Cd, 2.46 mg kg(-1) for Cu, 0223 mg kg(-1) for Ni and 17.4 mg kg(-1) for Zn. The coefficient of variability (CV) of soil Cd, Cu and rice Cd were 147%, 146% and 180%, respectively, indicating an extensive variability. While the CVs of other metals ranged from 23.4% to 84.3% with a moderate variability. Kriging interpolation procedure and the Local Moran's I index detected the locations of pollution hotspots of these four metals. Cd and Cu had a very similar spatial pattern, with contamination hotspots located simultaneously in the northwestern part of the study area, and there were obvious hotspots for soil Zn in the north area, while in the northeast for soil Ni. The existence of hotspots may be due to industrialization and other anthropogenic activities. An Enrichment Index (EI) was employed to measure the uptake of heavy metals by rice. The results indicated that the accumulation and availability of heavy metals in the soil-rice system may be influenced by both soil heavy metal concentrations and soil physico-chemical properties. Cross-correlograms quantitatively illustrated that EIs were significantly correlated with soil properties. Soil pH and organic matter were the most important factors controlling the uptake of heavy metals by rice. As results, positive measures should be taken into account to control soil pollution and to curtail metal contamination to the food chain in the areas of Wenling, which were the most polluted by toxic metals. (C) 2013 Elsevier B.V. All rights reserved.