环青海湖地区表层土壤重金属富集含量及其生态风险评价

doi:10.13866/j.azr.2021.02.12

摘要/Abstract

摘要：

为评估环青海湖地区表层土壤中重金属富集含量与生态风险状况,按网格法采集87组土壤样品,采用电感耦合等离子体原子发射光谱法（Inductively Coupled Plasma-Atomic Emission Spectrometry,ICP-AES）测定土壤重金属Cd、Cr、Pb、As、Cu、Zn和Ni,并利用内梅罗综合污染指数法、污染负荷指数法、相关性分析和因子分析等方法,探析了研究区土壤重金属含量、污染程度、生态风险及污染来源。结果表明：环青海湖地区表层土壤中重金属Cd、Pb污染在所研究的元素中最为严重,Cr、As、Cu、Zn和Ni次之,且草地的表层土壤重金属污染情况相比农田和沙地较严重。从污染负荷指数法来看,研究区土壤重金属整体上未达到污染水平,但部分采样点污染严重。内梅罗综合指数法分析显示,研究区整体上为重度污染,且单项污染指数存在不同程度超标,其污染程度依次为Cd>Pb>As>Cu>Zn>Ni>Cr。潜在生态风险指数法表明,整个研究区的综合潜在生态风险为中等程度,其中Cd、As的贡献率接近80%,部分区域潜在生态风险较高。相关性和因子分析可以发现,Cr、Pb、As、Cu、Zn和Ni之间的相关性显著,污染程度基本一致,很可能具有同源性。综上可知,环青海湖地区已出现土壤重金属污染,且存在潜在生态风险,需要采取适当的监测和相应治理措施。

关键词: 土壤重金属, 污染来源, 生态风险评价, 青海湖

Abstract:

To study the heavy metal enrichment content and ecological risk in the surface soil around Qinghai Lake, 87 groups of soil samples were collected by grid method, and the concentrations of the heavy metals (Cd, Cr, Pb, As, Cu, Zn, and Ni) were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The Nemero pollution index, pollution load index, correlation analysis, and factor analyses were used to determine the content of heavy metals, pollution degree, ecological risk, and pollution sources. The results showed that: Cd and Pb pollution in the surface soil around Qinghai Lake was the most serious, followed by Cr, As, Cu, Zn, and Ni. Compared with farmland and sandy land, heavy metal pollution in grassland surface soil was more serious. According to the pollution load index, the total amount of heavy metals in the soils of the study area did not reach the pollution level, but some sampling points were seriously polluted. The Nemero pollution index analysis implied that the whole study area was at the level of heavy pollution. The single pollution index exceeded the standard in different degrees. The pollution degree was Cd > Pb > As > Cu > Zn > Ni > Cr in turn. The potential ecological risk index analysis implied that the comprehensive potential ecological risk of the whole study area was medium, whereby the contribution rate of Cd and As was close to 80%, and some areas had high potential ecological risks. The correlation and factor analyses indicated that the correlation among Cr, Pb, As, Cu, Zn, and Ni were significant, and the pollution degree was the same, which was likely to be from the same source. In conclusion, heavy metal pollution of soil had occurred in the area around Qinghai Lake and elicited some potential ecological risks. Therefore, it is necessary to take appropriate monitoring and control measures.

Key words: soil heavy metals, sources of pollution, ecological risk assessment, Qinghai Lake

王若锦,邵天杰,卫佩茹. 环青海湖地区表层土壤重金属富集含量及其生态风险评价[J]. 干旱区研究, 2021, 38(2): 411-420.

WANG Ruojin,SHAO Tianjie,WEI Peiru. Enrichment content and ecological risk assessment of heavy metal in surface soil around Qinghai Lake[J]. Arid Zone Research, 2021, 38(2): 411-420.

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特征值	Cd	Cr	Pb	As	Cu	Zn	Ni
最小值	0.05	11.50	7.46	0.96	2.06	17.30	6.23
最大值	5.57	60.93	35.09	18.52	74.38	98.62	31.62
均值	0.62	41.35	21.86	11.73	19.33	63.51	21.18
变异系数Cv	2.29	0.32	0.30	0.32	0.46	0.31	0.33
青海湖土壤背景值^[42]	0.14	54.17	20.47	11.66	19.72	64.28	24.96

采样点土地利用类型	特征值	Cd	Cr	Pb	As	Cu	Zn	Ni
草地	最小值	0.05	11.50	7.46	3.27	4.89	22.51	6.23
	最大值	5.57	60.93	35.09	18.52	74.38	98.62	31.62
	均值	0.66	41.76	22.35	11.88	19.55	64.47	21.42
农田	最小值	0.15	43.35	17.80	13.91	21.07	65.43	22.63
	最大值	0.20	50.58	19.98	15.20	25.36	71.83	27.86
	均值	0.18	48.30	18.90	14.56	23.73	68.10	25.56
沙地	最小值	0.05	12.12	8.75	0.96	2.06	17.30	6.44
	最大值	0.25	48.85	21.36	9.76	17.51	61.33	19.37
	均值	0.15	26.43	15.00	6.03	10.59	40.11	11.98
青海湖土壤背景值		0.14	54.17	20.47	11.66	19.72	64.28	24.96

	CF							PLI	PLI_zone
	Cd	Cr	Pb	As	Cu	Zn	Ni	PLI	PLI_zone
最小值	0.38	0.18	0.37	0.07	0.09	0.23	0.21	0.24	0.89
最大值	42.17	0.96	1.72	1.43	3.34	1.30	1.09	1.80
平均值	4.68	0.65	1.07	0.90	0.87	0.84	0.73	0.94

元素名称	单项污染指数		内梅罗污染指数（每一元素）	内梅罗综合污染指数（每一样点）
元素名称	区间值	平均值	内梅罗污染指数（每一元素）	区间值	平均值
Cd	0.38~42.17	4.68	30.00	0.35~30.23	3.54
Cr	0.18~0.96	0.65	0.82
Pb	0.37~1.72	1.07	1.43
As	0.07~1.43	0.90	1.19
Cu	0.09~3.34	0.87	2.44
Zn	0.23~1.30	0.84	1.10
Ni	0.21~1.09	0.73	0.93

Pearson相关性	Cd	Cr	Pb	As	Cu	Zn	Ni
Cd	1.00
Cr	0.032	1.00
Pb	0.337^**	0.736^**	1.00
As	0.243^*	0.837^**	0.681^**	1.00
Cu	0.004	0.626^**	0.517^**	0.635^**	1.00
Zn	0.096	0.875^**	0.729^**	0.777^**	0.632^**	1.00
Ni	0.174	0.955^**	0.735^**	0.871^**	0.645^**	0.881^**	1.00