A comparative review on Malaysia’s water quality index model with international water quality index models for surface water quality classification

Abstract

Abstract Water Quality Index (WQI) is a grading and classification system. It is used to quantify the overall water quality status of a water resource for a given location and time. This paper aims at comparing the advantages and the limitations across several different types of WQI models (CCMEWQI, NSFWQI, IWQI, WQI Malaysia), in order to provide suggestions to improve the accuracy and sensitivity of the WQI models. IWQI and CCMEWQI are fully unbiased due to no weightage, however, statistical technique is recommended to be included in parameter selection step to increase its accuracy. WQI Malaysia is less sensitive in detection of emerging contaminants, as it is confined to six target specific parameters. To acquire more comprehensive result, upgrades should be made to optimise parameter selection and weightage assignment of different WQI models. Combined value and weightage method for each subindex could be considered in the WQI index calculation.