School of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, China.
Key Laboratory of Land Surface Pattern and Simulation, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
J Hazard Mater. 2024 Dec 5;480:135960. doi: 10.1016/j.jhazmat.2024.135960. Epub 2024 Sep 26.
Current total concentration-based methods for source attribution and risk assessment often overestimate metal risks, thereby impeding the formulation of effective risk management strategies. This study aims to develop a framework for source-specific risk assessment based on metal bioavailability in surface river sediments from a human-dominated seaward catchment in eastern China. Metal bioavailability was quantified using chemical fractionation results, and source apportionment was conducted using the positive matrix factorization (PMF) model. Risk assessment integrated these findings using two indices: the Potential Ecological Risk Index (PERI) and the Mean Probable Effect Concentration Quotient (mPEC-Q), with uncertainty addressed via Monte Carlo simulations. Results indicated that average total concentrations of Cu, Pb, Zn, Cr, Hg, Cd, and As exceeded their respective background levels by 1.63 to 15.00 times. The residual fraction constituted the majority, accounting for 53.84 % to 77.79 % of total concentrations, suggesting significant natural origins. However, source apportionment revealed a predominant contribution from anthropogenic activities, including industrial smelting, agricultural practices, and atmospheric deposition. The contributions were found to vary between 5.35 % and 40.03 % when the total concentration was adjusted to bioavailable content. Total concentration-based PERI/mPEC-Q assessments indicated high/moderate risk levels, decreasing to considerable/low risk levels with bioavailability adjustment. Hg and Cd were identified as priority metals. Further incorporating source appointment parameters into the risk assessment, industrial smelting was identified as the primary contributor, accounting for 66.06 % of total risk by total concentration and 65.63 % by bioavailability. This underscores the role of bioavailability in mitigating risk overestimation. Monte Carlo simulations validated industrial smelting as a major risk contributor. This study emphasizes the importance of considering bioavailability in the source-risk assessment of sediment-metals, crucial for targeted risk management in urbanized catchment areas.
目前基于总浓度的污染源解析和风险评估方法常常高估金属风险，从而阻碍了有效风险管理策略的制定。本研究旨在建立一个基于中国东部人为主导的入海流域表层河流水体沉积物中金属生物可利用性的污染源特定风险评估框架。使用化学形态分析结果量化金属生物可利用性，并使用正矩阵因子分解（PMF）模型进行源解析。风险评估综合这些发现，使用两个指数：潜在生态风险指数（PERI）和平均概率效应浓度商（mPEC-Q），并通过蒙特卡罗模拟解决不确定性。结果表明，Cu、Pb、Zn、Cr、Hg、Cd 和 As 的平均总浓度分别是其背景值的 1.63 至 15.00 倍。残渣态占主导地位，占总浓度的 53.84%至 77.79%，表明有显著的自然来源。然而，源解析表明，主要的污染源来自人为活动，包括工业冶炼、农业活动和大气沉降。当总浓度调整为生物可利用含量时，其贡献率在 5.35%至 40.03%之间变化。基于总浓度的 PERI/mPEC-Q 评估表明存在高/中度风险水平，调整生物可利用性后风险水平降低至可观/低风险水平。Hg 和 Cd 被确定为优先金属。进一步将源解析参数纳入风险评估中，工业冶炼被确定为主要贡献者，总浓度总风险的 66.06%和生物可利用性总风险的 65.63%归因于工业冶炼。这突显了生物可利用性在减轻风险高估方面的作用。蒙特卡罗模拟验证了工业冶炼是主要的风险贡献者。本研究强调了在沉积物金属的源-风险评估中考虑生物可利用性的重要性，这对于城市化流域的有针对性的风险管理至关重要。
