Integrated Health Risk Assessment of Heavy Metals in Suxian County, South China.

Daping Song,Dafang Zhuang,Dong Jiang,Qiao Wang,Jingying Fu

doi:10.3390/ijerph120707100

Abstract

The purpose of this study was to assess soil heavy metal contamination and the potential risk for local residents in Suxian county of Hunan Province, southern China. Soil, rice and vegetable samples from the areas near the mining industrial districts were sampled and analyzed. The results indicate that the anthropogenic mining activities have caused local agricultural soil contamination with As, Pb, Cu and Cd in the ranges of 8.47–341.33 mg/kg, 19.91–837.52 mg/kg, 8.41–148.73 mg/kg and 0.35–6.47 mg/kg, respectively. GIS-based mapping shows that soil heavy metal concentrations abruptly diminish with increasing distance from the polluting source. The concentrations of As, Pb, Cu and Cd found in rice were in the ranges of 0.02–1.48 mg/kg, 0.66–5.78 mg/kg, 0.09–6.75 mg/kg, and up to 1.39 mg/kg, respectively. Most of these concentrations exceed their maximum permissible levels for contaminants in foods in China. Heavy metals accumulate to significantly different levels between leafy vegetables and non-leafy vegetables. Food consumption and soil ingestion exposure are the two routes that contribute to the average daily intake dose of heavy metals for local adults. Moreover, the total hazard indices of As, Pb and Cd are greater than or close to the safety threshold of 1. Long-term As, Pb and Cd exposure through the regular consumption of the soil, rice and vegetables in the investigated area poses potential health problems to residents in the vicinity of the mining industry.

Highlights

In the course of the exploitation of heavy metal mining, a mining area and its surrounding environment may become affected by serious pollution from heavy metals
Compared with heavy metal concentrations in control soils, all heavy metals concentrations in the three functional areas were greatly elevated by the anthropogenic mining industry activities (Table 4)
The highest concentrations of soil heavy metals were found at Mining Area A, where the mean concentrations of As, polluted by lead (Pb), Cu and Cd were 244.25 mg/kg, 540.07 mg/kg, 111.03 mg/kg, and 5.72 mg/kg, respectively

Summary

Introduction

In the course of the exploitation of heavy metal mining, a mining area and its surrounding environment may become affected by serious pollution from heavy metals. Emissions of heavy metals can contaminate groundwater and surface water, agricultural soils, and food crops; they pose a health risk to residents near mining areas [1,2]. Numerous reports indicate that water, soil, vegetables and dust have been heavily polluted by lead (Pb), arsenic (As), copper (Cu), chromium (Cr), zinc (Zn) and cadmium (Cd) near the mining areas [3,4,5,6]. South China has encountered serious environmental problems posed by these heavy metals in recent years. Et al [3] noted that the mean concentrations of Pb, As and Cd in the soils of Chenzhou city in South China were 751.98 mg/kg, 459.02 mg/kg, and 6.77 mg/kg, respectively. Et al [9] concluded that the heavy metal concentrations in vegetables (mg/kg, dry weight basis) ranged from 5.0 to 14.3 for Cu, 34.7 to 170 for

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