Evaluation of Various Water Quality Indices for Water Quality Assessment of Sg. Sarawak

Abstract

Water quality is a term used to describe the chemical, physical and biological characteristics of water in respect to its suitability for a particular purpose and related with a set of standards. The knowledge of water quality and its content are essential to track any influx of water pollutants that are detrimental to human and ecosystem. The study aimed to examine the water quality status of Sg. Sarawak particularly in Waterfront and Satok Bridge based on three water quality monitoring approaches namely Water Quality Index (WQI), average NWQS and the extended NWQS (eNWQS). The eNWQS was designed based on Partial Least Square (PLS) regression where multivariate water quality data is correlated to training samples created according to the guideline of NWQS. Generally, the average NWQS and eNWQS corresponded well with the WQI in determining the river water quality status. The river water quality for both sampling points was categorized as slightly polluted with the index ranged from 62 to 68. In terms of sensitivity, the average NWQS approach was less sensitive because only discrete classes of I, II, III, IV and V were considered. The eNWQS shows better sensitivity but further study is required to verify the sensitivity level between eNWQS and WQI. This study emphasizes that the eNWQS may be useful and practical.