Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, Institute of Environmental Research at Greater Bay, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources, Guangzhou, 510006, China.
Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, Institute of Environmental Research at Greater Bay, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China.
Ecotoxicol Environ Saf. 2020 Jun 15;196:110529. doi: 10.1016/j.ecoenv.2020.110529. Epub 2020 Apr 1.
Cadmium (Cd) is a highly toxic element and non-essential to human. Herein, the source and fate of Cd were examined in a typical sediment profile from the North River, South China, which was affected by the massive Pb-Zn smelting activities for decades. An exceptionally high enrichment of Cd, 107-441 mg/kg, was observed across the whole profile. Approximately 50-75% of Cd was retained in the weak acid soluble fraction. Risk assessment based on geoaccumulation index (I), potential ecological risk index (E), bioavailable metal index (BMI) and toxic risk index (TRI) further indicated an extremely strong degree of potential ecological pollution and high toxic risks. The mineralogical composition of particles from the sediment profile exhibited the presence of pyrite, magnetite, wurtzite and greenockite. This further confirmed that Cd was migrated from smelting slags to the North River basin and enriched in sediment profile. Sediment Cd speciation analysis also implied a possible transformation of Cd from metal oxides in smelting slags to adsorbed phases and carbonates, which enhances the bioavailability of Cd. The findings indicate proper countermeasures or remediation approaches should be promptly taken towards high ecological risks of Cd arising from the depth profile extending nearly 1 m, due to lead-zinc smelting related activities.
镉 (Cd) 是一种剧毒元素，对人体非必需。本研究以受数十年大规模铅锌冶炼活动影响的珠江北江典型沉积柱样为对象，探讨了镉的来源与归宿。全柱样中镉的含量极高，范围在 107-441mg/kg。约 50-75%的镉以弱酸可提取态形式存在。基于地质累积指数 (I)、潜在生态风险指数 (E)、生物可利用金属指数 (BMI) 和毒性风险指数 (TRI) 的风险评估进一步表明，其具有极强的潜在生态污染和高毒性风险。柱样中颗粒的矿物组成显示出黄铁矿、磁铁矿、纤锌矿和闪锌矿的存在。这进一步证实了镉是从冶炼渣迁移到北江流域并在沉积柱中富积的。镉的形态分析也暗示了在冶炼渣中金属氧化物向吸附相和碳酸盐转化的可能性，这增加了镉的生物可利用性。研究结果表明，由于与铅锌冶炼相关的活动，导致 1 米深的沉积柱中镉的生态风险极高，应立即采取适当的对策或修复措施。
