Application of water quality indices for evaluating water quality and anthropogenic impact assessment

Abstract

Influences of different environmental variables are predicted to increase during the next century in association with abrupt changes in water quality. Determining the magnitude of such effects is difficult because variation of environmental variables is generally unpredictable, and thus, available data are rare. In this study, water quality monitoring was conducted based on new operational indicators and multi-metric indices to evaluate water quality status and biological response at temporal and spatial scales in west coastal water of Malaysia. The trophic state index ranged from 6 to 8 in temporal and spatial scales and suggested a highly productive system with a high trophic level, characteristic of a low-quality system. The eutrophication index varied from 0.65 to 4.45 and most of the samples had a bad (49%) or poor (45.5%) water quality, and only 5.3% of the water samples had a moderate productive system with a moderate trophic level. In West Port, anthropogenic sources and natural processes are likely to contribute to increase in nutrient concentrations and trophic level in the water column. During the study period, no secondary symptoms or eutrophication events occurred which could be due to water exchange and hydrodynamic turbulence, which prevented the eutrophication development at this region.