Spatial Geochemical Distribution and Sources of Heavy Metals in the Sediment of Langat River, Western Peninsular Malaysia

Abstract

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.

Heavy metal concentrations and ecological risk assessment of the suspended sediments of a multi-contaminated Brazilian watershed

“…The heavy metal concentration found in the suspended sediments (fraction < 63 µm) of the upstream cross section was lower than the average concentration found in the sediments of the Shing Mun, Tinto, Tigris, Lich, and Langat Rivers (Sin, Chua, Lo, & Ng, 2001;Morillo, Usero, & Gracia, 2002;Varol, 2011;Varol & Sen, 2012;Thuong et al, 2013;Lim, Aris, & Ismail, 2013). In the downstream cross section of the Ipojuca River, the metal concentrations were higher than those in the Langat River (Lim et al, 2013) but lower than those in the Shing Mun, Tinto, Tigris, and Lich Rivers. Such differences probably reflect the different anthropogenic inputs into each catchment area.…”

Occurrence of selected estrogenic compounds and estrogenic activity in surface water and sediment of Langat River (Malaysia)

“…The climate is influenced by the South West monsoon, which blows across the Strait of Malacca. A significant increase in human population along the Langat River was recorded; the number of people increased by 94.66 % from 598,661 people in 1990 to 1,165,267 people in 2000 (Juahir et al 2011;Lim et al 2013a).…”

Mercury contamination in the estuaries and coastal sediments of the Strait of Malacca

“…In order to avoid un-conservative conclusions, non-normally distributed raw data were not normalized prior to various statistical analyses (Lim et al 2013). Descriptive statistics of selected physico-chemical parameters and Hg concentrations in sediments, such as mean, minimum, maximum, standard deviation, and coefficient of variance, were calculated.…”