Concentration of selected heavy metals in water of the Juru River, Penang, Malaysia

Abstract

This study was conducted to determine heavy metal lead (Pb), cadmium (Cd), Zinc (Zn) and copper (Cu) concentrations in water body of the Juru River, Penang, Malaysia. A total of 20 sampling stations were chosen and water at 1 m below the surface was sampled using Van Dorn water sampler in December 2009 and April 2010. Collected water samples were kept in ice and acidified to pH 2 using nitrite acid (analytical grade HNO₃). Heavy metal concentrations were determined using inductively couple plasma (ICP model Perkin elmer/elan 9000) following standard method procedures. For comparison purposes, the river was divided into three different zones in the first and second samplings that is, upstream zone, middle reach zone and estuary zone and each zone consists of 7, 7, 6 sampling sites, respectively. Generally, results indicate that Pb and Cd and Cu in the first sampling were higher than the second sampling while the concentrations of Zn in the second sampling were higher than the first sampling. Also the results indicate that the Cd and Pb and Zn in the estuary zone were the lowest as compared to other zones. Meanwhile the highest concentration of Cu was in the middle zone. In conclusion, the lowest concentrations of some heavy metals were in estuary zone, it seems to be naturally due to dilution to heavy metals from sea water. Average metal concentrations from 20 water samples indicate that studied metal concentrations were still lower than Malaysian’s National Water Quality Standards (INWQS) guideline.

Keywords: Heavy metals, pollution, river, inductively couple plasma