Prolonged persistence of toxic cadmium (Cd), chromium (Cr) and lead (Pb) in the aquatic environment are due to its nonbiodegradable characteristic. A few studies have reported higher concentrations of these metals in the transboundary Langat River, Malaysia. This study determined the spatial and temporal distributions of Cd, Cr and Pb concentrations (2005–2015) in the Langat River along with assessing the status of these metals in the drinking water supply chain at the basin. Water samples were collected once in 2015 from the drinking water supply chain, i.e., from the river, treated water at plants, taps and filtration water at households. Determined mean concentrations of Cd, Cr and Pb by inductively coupled plasma mass spectrometry in the Langat River were within the drinking water quality standard of Malaysia and the WHO, except for the Pb (9.99 ± 1.40 µg/L) concentration, which was at the maximum limit, 10 µg/L. The spatial and temporal distribution of these metals’ concentrations indicate dilution of it downstream, along with the increasing trend in rainfall and water flow, especially during the northeast monsoon. Significant correlation and regression analysis of the Cd, Cr and Pb concentrations also indicate that the sources of this metal pollution are mainly the natural weathering of minerals along with anthropogenic activities in the basin. The determined overall water quality of the Langat River is categorized Class IIA (i.e., clean), which requires conventional treatment before drinking; however, the maximum removal efficiency of these metals by the plants at the basin was about 90.17%. Therefore, the proactive leadership roles of the local authorities will be appropriate to reduce the pollution of this river as well as introducing a two-layer water filtration system at the Langat River Basin to accelerate the achievement of a sustainable drinking water supply.

中文翻译：

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调查饮用水供应链中镉、铬和铅的状况，以确保马来西亚的饮用水质量

有毒的镉 (Cd)、铬 (Cr) 和铅 (Pb) 在水生环境中长期存在是由于其不可生物降解的特性。一些研究报告称，马来西亚跨界朗加特河中这些金属的浓度较高。本研究确定了 Langat 河中 Cd、Cr 和 Pb 浓度（2005-2015 年）的时空分布，并评估了这些金属在流域饮用水供应链中的状况。2015 年从饮用水供应链中采集了一次水样，即河流、工厂处理水、自来水和家庭过滤水。通过电感耦合等离子体质谱法测定的 Langat 河中 Cd、Cr 和 Pb 的平均浓度在马来西亚和 WHO 的饮用水质量标准范围内，但 Pb 除外 (9. 99 ± 1.40 µg/L) 浓度，最高限值为 10 µg/L。这些金属浓度的时空分布表明它在下游被稀释，随着降雨和水流的增加趋势，特别是在东北季风期间。Cd、Cr和Pb浓度的显着相关性和回归分析也表明，这种金属污染的来源主要是盆地内矿物的自然风化和人为活动。Langat River 的整体水质被确定为 IIA 级（即清洁），需要在饮用前进行常规处理；然而，流域植物对这些金属的最大去除效率约为 90.17%。所以，