Contamination Evaluation and Source Identification of Heavy Metals in the Sediments from the Lishui River Watershed, Southern China.

Fang Shen,Longjiang Mao,Min Ding,Runxia Sun,Jijing Du,Zhihai Tan

doi:10.3390/ijerph16030336

Abstract

Seven heavy metals (Cr, Mn, Co, Ni, Cu, Zn, Pb) were measured in surface sediments from the Lishui River watershed, an area with increased soil erosion in China. The mean concentrations of heavy metals were 61.20 mg/kg (Cr), 757.15 mg/kg (Mn), 9.39 mg/kg (Co), 25.31 mg/kg (Ni), 22.84 mg/kg (Cu), 91.66 mg/kg (Zn), and 40.19 mg/kg (Pb), respectively. The spatial distribution of heavy metals was site-specific, exhibiting a remarkably high level in the sampling stations with intense agricultural activities (Lixian) and industrial activities (Jinshi). Contamination indexes including contamination factor, pollution load index, nemerow multi-factor index, potential ecological risk index, and human health risk were used to assess the pollution degree of the river sediments. The results indicated the pollution degree of heavy metals decreased in the order of Mn > Pb > Zn > Cr > Cu > Ni > Co. Heavy metals resulted in non-pollution to moderate pollution, with low ecological risk and an acceptable carcinogenic risk caused by Cr and Ni for children and adults. Person’s correlation analysis and principal component analysis, coupled with cluster analysis, revealed that the sediments from the Lishui River were mainly influenced by two sources. Cr, Co, Ni, and Cu were mainly derived from natural sources, while Mn, Zn, and Pb originated from agricultural and industrial activities, mining, and vehicular traffic.

Highlights

IntroductionMore than 99% of heavy metals entering aquatic system can be stored in the sediment indifferent ways [1]
According to statistics, more than 99% of heavy metals entering aquatic system can be stored in the sediment indifferent ways [1]
The principal aims of this research are to (1) measure the contamination and investigate the distribution of seven heavy metals (Cr, Mn, Co, Ni, Cu, Zn, and Pb), (2) use sediment quality indicators including the contamination factor, the pollution load index, and the nemerow multi-factor index to assess the pollution degree of river sediments, (3) use potential ecological risk and health index to assess the risk of heavy metals, and (4) use multivariate analysis to distinguish the possible sources of heavy metals

Summary

Introduction

More than 99% of heavy metals entering aquatic system can be stored in the sediment indifferent ways [1]. River sediments are important repositories, sinks, and carriers for heavy metals [2,3]. They play an important role in assessing metal contamination and tracing contamination sources [4]. Following the frequency of natural and anthropogenic activities and the discharge of heavy metals into rivers, contamination is ubiquitous in the aquatic environment [5]. Anthropogenic activities are the major cause of heavy metal pollution in the aquatic environment, such as industrial discharges, vehicular exhaust, mining operations, agricultural cultivation, and atmospheric precipitation [6,7]. References Cr Mn Co Ni Cu Zn Pb This study [36] [37] [5]

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