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河南荥阳市耕地土壤重金属分布特征及来源解析

Distribution Characteristics, Ecological Risks, and Source Identification of Heavy Metals in Cultivated Land in Xingyang City

  • 摘要: 耕地质量关系着人民生活,而重金属是影响耕地质量的重要因素之一。根据全国土壤污染状况调查显示,中国耕地环境状况不容乐观,对耕地的重金属调查分析迫在眉睫。但仅简单地对重金属含量水平及来源类型进行判断已不足以为区域土壤重金属污染治理提供支持,而通过对各类污染源贡献率的定量计算,不仅可以明确农田土壤重金属分布特征,同时可判别污染源类别及来源,从而识别优先控制的污染元素,为重金属污染精准管控提供关键信息。本文采集河南荥阳市耕地表层土壤样品(0~20cm),应用电感耦合等离子体质谱和发射光谱法(ICP-MS/OES)、原子荧光光谱法(AFS)及离子选择电极法(IES)对As、Cd、Cr、Cu、Hg、Ni、Pb、Zn等8种重金属进行测试和pH分析;利用多元统计、绝对因子分析-多元线性回归(APCS-MLR)受体模型探讨研究区8种重金属污染含量空间分布特征及来源,利用富集因子和地累积指数开展土壤污染评价。结果表明:①耕地土壤中重金属含量整体偏高。除Cr外,其他元素为郑州市土壤背景值的1.04~1.40倍,其中Cd的累积效应较明显。②研究区重金属高值区主要分布于荥阳市城区周边。③基于富集因子法、相关性分析、主成分分析及APCS-MLR源解析结果显示,研究区重金属主要有三个来源:自然源对Ni、As、Cu、Cr的贡献率分别为98%、94%、80%及63%;工业源对Cd的贡献率为78%;其他源则主要是农业化肥源、燃煤源的混合源,对Cr、Pb、Hg的贡献率分别为37%、35%及33%。④地累积指数表明,研究区各重金属以无污染为主,而Cd超标率最高,其中度、中-重度污染、重度污染样点数分别为19个、5个及3个,并存在1个极重度污染样点。综上,Cd在研究区耕地中富集较明显,为潜在的主要污染元素;工业源、自然源、农业化肥源及燃煤源是重金属的主要来源,表明人类活动已对研究区耕地产生影响,需采取措施避免该影响进一步加剧。

     

    Abstract: The quality of arable land is closely related to people’s livelihoods, and heavy metals are one of the significant factors affecting arable land quality. The spatial distribution characteristics and sources of eight heavy metal pollutants in the cultivated land of Xingyang City were investigated by multivariate statistical analysis and absolute principal component score-multiple linear regression (APCS-MLR) receptor model, and soil pollution assessment was carried out by enrichment factor and land accumulation index. The results show that the heavy metal content in cultivated soil was higher as a whole, and the accumulation effect of Cd was more obvious. The heavy metals in the study area were mainly distributed around Xingyang City. Industrial, natural, and the mixed sources of agricultural fertilizer and coal-burning are the main sources of heavy metals. The accumulative index shows that the heavy metals in the study area are mainly unpolluted, and the Cd exceeding standard rate is the highest. Therefore, it indicates that human activities have affected the cultivated land in the study area, and measures should be taken to avoid further aggravation. The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202306300084.

     

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