Evaluation of heavy metal contamination in sediments of the Linggi River, Malaysia

Abstract

This study evaluates the concentrations and contamination levels of selected heavy metals (Mn, As, Cr, Fe, Zn, and Co) in surface sediments from seven locations along the Linggi River, Malaysia. Using Instrumental Neutron Activation Analysis (INAA), elemental concentrations were quantified, and contamination indices were applied to assess ecological risks. Results showed that arsenic (As) exhibited extremely high enrichment, with EF values ranging from 40.02 (S1) to 70.79 (S7), and Igeo values from 4.42 to 5.06, categorizing it as heavily to extremely polluted. Chromium (Cr) showed moderate enrichment (EF: 1.77–2.55; Igeo: –0.34 to 0.26), while zinc (Zn) had minor enrichment (EF: 1.01–1.51; Igeo: –0.92 to –0.57). Manganese (Mn), cobalt (Co), and iron (Fe) exhibited EF and Igeo values below 1 and 0, respectively, indicating minimal anthropogenic influence. The Pollution Load Index (PLI) values ranged from 1.02 (S5) to 1.37 (S7), confirming pollution across all sites, with S7 being the most contaminated. When compared against Canadian and Consensus Freshwater Sediment Quality Guidelines, arsenic and chromium levels exceeded Threshold Effect Levels (TEL) and Threshold Effect Concentrations (TEC), indicating significant ecological risk. These findings highlight the need for urgent environmental monitoring and pollution control in the Linggi River system.