Development of water quality index of ex-mining ponds in Malaysia

Abstract

In this paper, a study on the development  of water quality index of ex-mining ponds was carried out for proper assessment  and utilization of the abundant ex-mining ponds in Malaysia. Heavy metals were analyzed using inductively coupled plasma mass spectrophotometer (ICPMS), and physico chemical parameters were analyzed in-situ. Chemometric analysis was successfully applied for the parameter selection process. The water quality index of existing Malaysian river did not accommodate the toxic metal pollutants that dominanted in ex-mining water. The acceptable index should therefore incorporate the metal pollutants in order to evaluate the quality status of ex-mining water for human consumption which is the major point of consideration. Two water quality indices were developed to assess the water quality status of ex-mining ponds with reference to Malaysia’s water quality standard (INWQS). The heavy metal index was comprised of contribution from Pb, As, and Cd as the selected metals, while the physico-chemical parameter index has BOD, pH, DO, and AN. Chemometric analysis revealed the dominance of the selected heavy metals in ex-mining water, and physico-chemical parameters were important in water quality monitoring. Heavy metal water quality index revealed that most ex-mining ponds in Klang Valley were classified to be very poor hence could not be used for human consumption. Due to domestic input in some of the lakes in Klang Valley, the physico-chemical water quality index was in very poor status as well.  In Melaka and Negeri Sembilan, ex-mining ponds and lakes were classified as excellent in both indices.