Swarnalatha K, Letha J, Ayoob S, Nair Ajith G
Environmental Engineering Division, Department of Civil Engineering, College of Engineering, Trivandrum, Kerala, 695 016, India,
Environ Monit Assess. 2015 Jun;187(6):322. doi: 10.1007/s10661-015-4558-7. Epub 2015 May 6.
The risk assessment of heavy metal contamination was carried out in sediments of an urban tropical lake system (Akkulam-Veli) under threat from rapid unplanned urbanization and poor sewage management. Heavy metals were selected due to their persistent and bioaccumulative nature. Sequential extraction of the metals was carried out to resolve the sediments to their component phases. Well-established models were employed for risk analysis. The two pathways of contamination-ingestion and dermal contact-were considered for assessing risk. Risk Assessment Code of each metal was determined based on the lability of it in the different component phases. Cd was found to be the most hazardous metal by virtue of its high concentration in exchangeable and carbonate phases. Hazard indices of the metals were determined based on their total concentration in Akkulam-Veli (AV) Lake sediments. All heavy metals studied fall well below the threshold limit. However, Cr, Pb, and As, on account of their known toxicity, need to be monitored. Ni content in the lake system could potentially cause cancer to 134 adults in a population of one million. Concentrations of other metals are at carcinogenically safe limits. The study stresses the looming hazard faced by the Akkulam-Veli Lake system by heavy metal contaminants and the urgency in formulating remedial management plans.
在一个受到快速无序城市化和污水管理不善威胁的城市热带湖泊系统（阿库勒姆 - 韦利湖）的沉积物中，开展了重金属污染风险评估。由于重金属具有持久性和生物累积性，故对其进行了研究。对沉积物中的金属进行了连续提取，以将沉积物解析为其组成相。采用成熟的模型进行风险分析。在评估风险时考虑了两种污染途径——摄入和皮肤接触。根据每种金属在不同组成相中的活性确定其风险评估代码。由于镉在可交换态和碳酸盐态中的浓度较高，被发现是最具危害性的金属。基于阿库勒姆 - 韦利湖沉积物中金属的总浓度确定了金属的危害指数。所有研究的重金属含量均远低于阈值。然而，鉴于铬、铅和砷已知的毒性，需要对其进行监测。该湖泊系统中的镍含量可能会使每百万人口中的134名成年人患癌症。其他金属的浓度处于致癌安全限值内。该研究强调了阿库勒姆 - 韦利湖系统面临的重金属污染物潜在危害以及制定补救管理计划的紧迫性。
