罗松英 柯思茵 王嘉琦 陈东平 刘诺玲

摘要：【目的】探究湛江市郊蔬菜地土壤重金属污染现状及来源，为农产品安全生产提供参考依据。【方法】测定广东省湛江市郊麻章区、赤砍区和霞山区蔬菜地29个土壤样品的As、Cd、Cr、Cu、Hg、Pb、Ni和Zn 8种重金属含量，并分析其空间分布特征，对研究区污染情况进行单因子污染指数、内梅罗综合污染指数和潜在生态风险指数法综合评价，结合相关性分析和主成分分析探讨其重金属来源。【结果】湛江市郊蔬菜地8种重金属元素含量平均值均未超过国家土壤环境质量二级标准限值，但个别样点的Cd、Hg、Cu和Zn等元素含量超标;除As外，其余重金属元素含量平均值均超过广东省砖红壤背景值;且含量空间差异较明显，高值区多出现在霞山区。研究区蔬菜地土壤重金属综合污染指数为安全等级，但逼近警戒值0.7;土壤重金属为强潜在生态风险。土壤中Pb、Cu、Cr、Ni、Cd和Zn间具有强相关性，主成分累積贡献率达60.045%，反映这些重金属元素可能具有相近或相同的污染来源;As与Hg间相关性极显著（P<0.01），但与其他元素相关性不明显，主成分方差贡献率为22.064%，说明这两种重金属元素具有同源性。【结论】湛江市郊蔬菜地重金属污染属于安全范围，但存在强潜在生态风险，主要受工业生产、农药化肥和生活排污的影响。

关键词： 重金属污染;空间分布;污染指数;蔬菜地;湛江市郊

中图分类号： S155.41;X53                          文献标志码： A 文章编号：2095-1191（2019）08-1709-09

Spatial distribution and source analysis of heavy metals content in vegetable field soils in suburb of Zhanjiang

LUO Song-ying1， KE Si-yin2， WANG Jia-qi1， CHEN Dong-ping2， LIU Nuo-ling1

（1Department of Geography， Lingnan Normal University， Zhanjiang， Guangdong  524048， China; 2School of Earth Science and Geological Engineering， Sun Yat-sen University， Guangzhou  510275， China）

Abstract：【Objective】The aim was to investigate the status and sources of heavy metal pollution in vegetable soils in suburbs of Zhanjiang， and provide reference for safe production of agricultural products. 【Method】The contents of As， Cd， Cr， Cu， Hg， Pb， Ni and Zn in 29 soil samples from vegetable fields in Zhanjiang suburbs（Mazhang District， Chikan District and Xiashan District） were determined and its spatial distribution characteristics were analyzed. The single factor pollution index， Nemerow pollution index and potential ecological risk index were used for pollution assessment， and the sources of heavy metals were discussed by correlation analysis and principal component analysis. 【Result】The results were as follows： the average content of the eight heavy metal elements were not exceeding the national soil environment quality level standard， but the content of Cd， Hg， Cu and Zn in some sampling points were exceeding the standard， and most of heavy metals have exceeded the background value of laterite in Guangdong except As. Spatial variations of heavy metals contents were obvious， and high values occurred in Xiashan district. The comprehensive pollution index of soil heavy metals was in a safety grade， but approaching the warning value 0.7. The potential ecological risk assessment indicated that the soil of vegetable fields was in strong pollution. There was strong correlation among Pb， Cu， Cr， Ni， Cd and Zn in soil， and the cumulative contribution rate of the principal components was 60.045%， which reflected that these heavy metals may have similar or the same pollution sources. The correlation between As and Hg was very significant（P<0.01）， but it was not obvious with other elements. The variance contribution rate of the principal components was 22.064%， indicating that the two heavy metals had the same origin. 【Conclusion】Heavy metal pollution in vegetable fields in Zhanjiang suburbs belongs to the safe grade but with strong potential ecological risks， it is mainly affected by industrial activities， pesticide fertilizer and waste water discharge.

Key words： heavy metal pollution; spatial distribution; pollution index; vegetable field; Zhanjiang suburb

0 引言

【研究意义】土壤既是自然环境的构成要素，又是农业生产重要的自然资源，承担着环境中约90%来自各方面的污染物（温雅君等，2013）。……