An investigative study was carried out in Langat River to determine the heavy metal pollution in the sediment with 22 sampling stations selected for the collection of sediment samples. The sediment samples were digested and analyzed for extractable metal ((48)Cd, (29)Cu, (30)Zn, (33)As, (82)Pb) using the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Parameters, such as pH, Eh, electrical conductivity (EC), salinity, cation exchange capacity (CEC) and loss on ignition (LOI) were also determined. The assessment of heavy metal pollution was derived using the enrichment factors (EF) and geoaccumulation index (I(geo)). This study revealed that the sediment is predominantly by As > Cd > Pb > Zn > Cu. As recorded the highest EF value at 187.45 followed by Cd (100.59), Pb (20.32), Zn (12.42) and Cu (3.46). This is similar to the I(geo), which indicates that the highest level goes to As (2.2), exhibits moderately polluted. Meanwhile, Cd recorded 1.8 and Pb (0.23), which illustrates that both of these elements vary from unpolluted to moderately polluted. The Cu and Zn levels are below 0, which demonstrates background concentrations. The findings are expected to update the current status of the heavy metal pollution as well as creating awareness concerning the security of the river water as a drinking water source.

This paper determines the controlling factors that influence the metals' behavior water-sediment interaction facies and distribution of elemental content (75As, 111Cd, 59Co, 52Cr, 60Ni, and 208Pb) in water and sediment samples in order to assess the metal pollution status in the Langat River. A total of 90 water and sediment samples were collected simultaneously in triplicate at 30 sampling stations. Selected metals were analyzed using ICP-MS, and the metals' concentration varied among stations. Metal concentrations of water ranged between 0.08–24.71 μg/L for As, <0.01–0.53 μg/L for Cd, 0.06–6.22 μg/L for Co, 0.32–4.67 μg/L for Cr, 0.80–24.72 μg/L for Ni, and <0.005–6.99 μg/L for Pb. Meanwhile, for sediment, it ranged between 4.47–30.04 mg/kg for As, 0.02–0.18 mg/kg for Cd, 0.87–4.66 mg/kg for Co, 4.31–29.04 mg/kg for Cr, 2.33–8.25 mg/kg for Ni and 5.57–55.71 mg/kg for Pb. The average concentration of studied metals in the water was lower than the Malaysian National Standard for Drinking Water Quality proposed by the Ministry of Health. The average concentration for As in sediment was exceeding ISQG standards as proposed by the Canadian Sediment Quality Guidelines. Statistical analyses revealed that certain metals (As, Co, Ni, and Pb) were generally influenced by pH and conductivity. These results are important when making crucial decisions in determining potential hazardous levels of these metals toward humans.

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The present study employed geochemical and multivariate analyses to assess the level of heavy metals (As, Cu, Cr, Ni, Pb, and Zn) in sediment along the lower reaches of the Langat River. The sediment samples were digested and analyzed for total metals by an inductively coupled plasma-mass spectrometry (ICP-MS). Selected physicochemical parameters such as pH, redox potential (Eh), electrical conductivity (EC), salinity, organic matter and cation exchange capacity (CEC) were also determined. The metal concentration from this study area was compared with interim sediment quality guidelines (ISQG). Most sediment samples did not exceed the ISQG. Geo-accumulation index (Igeo) revealed that certain sampling stations were classified as strongly polluted with respect to As and classified as moderately polluted for Pb. Based on the enrichment factor (EF) values, most sampling stations were categorized as 'very severely enriched to extremely severely enriched for As and only 3% were moderately enriched. For Pb, pH, Eh, and CEC pose considerable influence on the composition of heavy metal in the sediment as confirmed by Pearson correlation. The hierarchical cluster analysis (HCA) revealed that sediment in the study area could be divided into two major clusters. Cluster 1 was mainly affected by the agricultural and industrial activities while Cluster 2 was heavily affected by seawater. The forensic investigation via the use of geostatistical and geochemical approaches revealed two pollution sources: (i) manmade (agricultural and industrial activities), and (ii) natural processes (seawater intrusion and geological weathering). The quantification of heavy metal concentrations thus provides a better understanding of the potential ecological risks and contamination status of the sediment. The vulnerable areas identified in this study should be given the highest priority for mitigation measures in order to alleviate pollution from industries and agriculture areas. The incorporation of source apportionment method to further understand the dynamics of environmental processes is recommended for future studies to assist in identifying possible high pollution-risk areas.