沉积物中重金属的富集威胁着珠江流域水环境的安全。研究珠江流域沉积物中重金属污染状况可以为流域沉积物重金属污染防治和水环境科学管理提供支撑。收集了2009—2022 年发表的珠江流域沉积物中重金属(As、Cd、Pb、Cr、Cu和Zn)含量的数据,运用数理统计分析、相关性分析和正交矩阵分解模型(PMF)探讨了珠江流域沉积物中重金属的分布特征和污染来源,采用地累积指数和潜在生态风险指数法对重金属污染程度和生态风险进行了评价。结果表明,珠江流域沉积物中As、Cd、Pb、Cr、Cu和Zn平均含量分别为49.29、2.76、63.97、67.44、48.72和186.60 mg·kg^-1,其中As、Cd、Pb和Zn超过了中国南方水系沉积物均值,而Cu和Cr接近中国南方水系沉积物均值。珠江流域沉积物中Cd和As污染最为严重,其中Cd主要为偏中度-中度污染,As主要为轻度-偏中度污染,其余重金属主要为轻度-无污染。沉积物重金属单因子危害指数排序为:Cd>As>Pb>Cu>Zn>Cr。Cd在整个珠江流域内都表现出较为严重的危害程度,贡献了生态风险指数的70.73%~93.73%;As在西江、南北盘江和珠江三角洲危害程度均为中等;其余重金属Pb、Cr、Cu和Zn危害程度均为轻微。PMF解析结果表明,沉积物中重金属主要来源为矿业活动和农业活动的复合污染源、燃煤和工业活动污染源、大气沉降和交通污染源以及自然源,贡献分别为21%、17%、35%和27%,其中前三者均属于人为来源,贡献累计可达73%。Cd和As主要受到矿业活动、工业活动和农业活动的影响,Pb主要来源于交通污染和矿业活动,Cr主要为自然源,而Cu和Zn来源比较复杂,受到4种来源的综合影响。

The enrichment of heavy metals in sediments poses a serious threat to the aquatic environment of the Pearl River Basin. Exploring heavy metal pollution in the sediments of the Pearl River Basin is crucial for preventing and controlling such pollution and for supporting the scientific management of the aquatic environment. Data on the contents of heavy metals (As, Cd, Pb, Cr, Cu, and Zn) in the sediments of the Pearl River Basin published from 2009 to 2022 were collected. Through mathematical statistical analysis, correlation analysis, and positive matrix factorization (PMF) modeling, we discussed the distribution characteristics and pollution sources of heavy metals in the sediments of the Pearl River Basin. We also evaluated the pollution degree and ecological risk of heavy metals based on the geo-accumulation index and potential ecological risk index. The results revealed that the average content of As, Cd, Pb, Cr, Cu, and Zn in the sediments of the Pearl River Basin were 49.29, 2.76, 63.97, 67.44, 48.72, and 186.60 mg·kg^-1, respectively. Among them, As, Cd, Pb, and Zn exceeded the average values of stream sediments in southern China, while Cu and Cr were close to the average values of stream sediments in southern China. The pollution of Cd and As in the sediments of the Pearl River Basin is the most serious, with Cd classified as mild to moderate degree and As mainly at a slight degree, while the other four heavy metals showed no pollution. The order of single-factor hazard index of heavy metals in sediments was: Cd>As>Pb>Cu>Zn>Cr, with Cd showing a serious damage level throughout the Pearl River Basin, contributing 70.73% to 93.73% of the ecological risk index. The damage level of As in the Xijiang River, Nanbeipan River, and Pearl River Delta was moderate, while the damage level of other heavy metals such as Pb, Cr, Cu, and Zn was slight. The results of the PMF analysis indicated that the main sources of heavy metals in sediments were the combined pollution sources of mining activities and agricultural activities, coal and industrial activities, atmospheric deposition and traffic pollution sources, and natural sources, with contributions of 21%, 17%, 35%, and 27%, respectively. The first three were all anthropogenic sources, with a cumulative contribution of 73%. Cd and As were mainly derived from mining activities, industrial activities, and agricultural activities. Pb was primarily derived from traffic pollution and mining activities. Cr mainly originated from natural sources, while Cu and Zn were influenced by all four sources.