Heavy metal and insecticide distribution and accumulation at the Bertam Agricultural Watershed in Cameron Highlands, Pahang, Malaysia

Abstract

This study aimed to determine the status of heavy metal concentrations of Cd, Cr, Ni, Pb, Zn, Cu, and Fe in the water bodies of Bertam River, Cameron Highlands, which traverses agricultural areas. Water samples were randomly collected in three replicates from 10 sampling points along the river. Then, the samples were tested for metal concentrations using inductively coupled plasma mass spectrometry. The insecticides cypermethrin and chlorpyrifos, which are widely used by farmers, were analyzed. The water samples were drawn into a C18 cartridge. Cypermethrin or chlorpyrifos absorbed by the cartridge were extracted using 6 mL of acetone and then injected into the gas chromatography-electron capture detector. In this study, the highest mean concentration was Fe (96.04 ± 90.43 ppb), followed by Zn (5.68 ± 0.2.34 ppb), Cu (5.13 ± 2.98 ppb), Cr (1.53 ± 0.19 ppb), Ni (0.85 ± 0.22 ppb), Pb (0.85 ± 1.61 ppb), and Cd (0.027 ± 0.02 ppb); hence, Fe> Zn> Cu> Pb> Cr> Ni> Cd. However, the concentrations of selected heavy metals in the water samples were below the standards recommended by the WHO. The overall average concentrations of chlorpyrifos and cypermethrin in the dry season ranged from 0.40 ppm to 2.37 ppm and from 0.001 ppb to 0.13 ppb, respectively. By contrast, the overall average concentrations in the rainy season ranged from 0.04 ppm to 0.80 ppm and from 0.00 ppb to 0.010 ppb, respectively. Results showed that runoff from the agricultural area affected water quality.