Priority areas identification for arable soil pollution prevention based on the accumulative risk of heavy metals

Abstract

Preventing impending heavy metal pollution in arable soil is crucial for ensuring food security and avoiding challenging remediation. The key to effective prevention strategies lies in proactive identifying currently unpolluted regions that are susceptible to future pollution, which current methods, predicated on the assessment of static pollution status, inadequately characterize the potential accumulative changes in soil heavy metals. In this paper, we proposed a framework for identifying priority areas based on the discrepancy between pollution status and accumulative risk, by considering the specific factors that influence heavy metal accumulation in soil. We applied this framework to a region of Xiangtan County to pinpoint priority areas for preventing impending pollution. The result revealed certain areas exhibited a relatively higher accumulative risk of heavy metal pollution, despite not having reached severe pollution levels for the heavy metals Arsenic (As), Cadmium (Cd), Chromium (Cr), Mercury (Hg), and Lead (Pb), among which the area ratio reached nearly 6 %, 36 %, 1 %, 3 %, 4 %, respectively. The priority areas for preventing Cd pollution were primarily concentrated in the mid-southern, mid-western, and eastern regions, while that of the other four heavy metals were predominantly distributed in the mid-northern regions with varying continuous ranges. Moreover, we prioritized the main pollution risks for comprehensive prevention in the following order: Cd, As, Pb, Hg, and Cr, and investigated the key factors contributing to the pollution of these heavy metals. The insights presented in this study have significant implications for soil environmental quality management, offering valuable guidance for implementing precise measures to prevent heavy metal pollution and efficiently control pollution sources.