Carbon-Water Research Station in Karst Regions of Northern Guangdong, School of Geography and Planning, Sun Yat-sen University, Guangzhou, 510275, China.
Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
J Environ Manage. 2024 May;359:120943. doi: 10.1016/j.jenvman.2024.120943. Epub 2024 May 3.
Historical reconstruction of heavy metals (HMs) contamination in sediments is a key for understanding the effects of anthropogenic stresses on water bodies and predicting the variation trends of environmental state. In this work, eighteen sediment cores from the Pearl River Estuary (PRE) were collected to determine concentrations and geochemical fractions of HMs. Then, their potential sources and the relative contributions during different time periods were quantitatively identified by integrating lead-210 (Pb) radioisotope dating technique into positive matrix factorisation (PMF) method. Pollution levels and potential ecological risks (PERs) caused by HMs were accurately assessed by enrichment factors (EF) based on establishment of their geochemical baselines (GCBs) and multiparameter evaluation index (MPE). HMs concentrations generally showed a particle size- and organic matter-dependent distribution pattern. During the period of 1958-1978, HMs concentrations remained at low levels with agricultural activities and natural processes being identified as the predominant sources and averagely contributing >60%. Since the reform and opening-up in 1978, industrial and traffic factors become the primary anthropogenic sources of HMs (such as Cu, Zn, Cd, Pb, Cr, and Ni), averagely increasing from 22.1% to 28.1% and from 11.6% to 23.4%, respectively. Conversely, the contributions of agricultural and natural factors decreased from 37.0% to 28.5% and from 29.3% to 20.0%, respectively. Subsequently, implementation of environmental preservation policies was mainly responsible for the declining trend of HMs after 2010. Little enrichment of sediment Cu, Zn, Pb, Cr and Ni with EFs (0.15-1.43) was found in the PRE, whereas EFs of Cd (1.16-2.70) demonstrated a slight to moderate enrichment. MPE indices of Cu (50.7-252), Pb (52.0-147), Zn (35.5-130), Ni (19.6-71.5), Cr (14.2-68.8) and Cd (0-9.90) highlighted their potential ecological hazards due to their non-residual fractions and anthropogenic sources.
历史上对重金属（HM）在沉积物中的污染进行重建是了解人为压力对水体影响和预测环境状态变化趋势的关键。在这项工作中，从珠江口采集了 18 个沉积物岩芯，以确定重金属的浓度和地球化学形态。然后，通过将铅-210（Pb）放射性同位素测年技术与正矩阵因子化（PMF）方法相结合，定量识别了它们的潜在来源及其在不同时期的相对贡献。通过建立地球化学基线（GCB）和多参数评价指数（MPE），基于富集因子（EF）准确评估了重金属造成的污染水平和潜在生态风险（PER）。HM 浓度普遍呈现出与粒径和有机质相关的分布模式。在 1958-1978 年期间，HM 浓度保持在低水平，农业活动和自然过程被确定为主要来源，平均贡献超过 60%。自 1978 年改革开放以来，工业和交通因素成为重金属的主要人为污染源（如 Cu、Zn、Cd、Pb、Cr 和 Ni），平均从 22.1%增加到 28.1%和从 11.6%增加到 23.4%。相反，农业和自然因素的贡献分别从 37.0%下降到 28.5%和从 29.3%下降到 20.0%。随后，环境保护政策的实施主要导致了 2010 年后重金属浓度的下降趋势。在珠江口，沉积物 Cu、Zn、Pb、Cr 和 Ni 的富集因子（EF）（0.15-1.43）没有明显富集，而 Cd 的 EF（1.16-2.70）显示出轻微到中度富集。Cu（50.7-252）、Pb（52.0-147）、Zn（35.5-130）、Ni（19.6-71.5）、Cr（14.2-68.8）和 Cd（0-9.90）的 MPE 指数突出了它们由于非残留部分和人为来源而具有的潜在生态危害。
