Spatial water quality assessment of Langat River Basin (Malaysia) using environmetric techniques

Abstract

This study investigates the spatial water quality pattern of seven stations located along the main Langat River. Environmetric methods, namely, the hierarchical agglomerative cluster analysis (HACA), the discriminant analysis (DA), the principal component analysis (PCA), and the factor analysis (FA), were used to study the spatial variations of the most significant water quality variables and to determine the origin of pollution sources. Twenty-three water quality parameters were initially selected and analyzed. Three spatial clusters were formed based on HACA. These clusters are designated as downstream of Langat river, middle stream of Langat river, and upstream of Langat River regions. Forward and backward stepwise DA managed to discriminate six and seven water quality variables, respectively, from the original 23 variables. PCA and FA (varimax functionality) were used to investigate the origin of each water quality variable due to land use activities based on the three clustered regions. Seven principal components (PCs) were obtained with 81% total variation for the high-pollution source (HPS) region, while six PCs with 71% and 79% total variances were obtained for the moderatepollution source (MPS) and low-pollution source (LPS) regions, respectively. The pollution sources for the HPS and MPS are of anthropogenic sources (industrial, municipal waste, and agricultural runoff). For the LPS region, the domestic and agricultural runoffs are the main sources of pollution. From this study, we can conclude that the application of environmetric methods can reveal meaningful information on the spatial variability of a large and complex river water quality data.

River Bank Filtration: Study of Langat River Water and Borehole Water Quality

“…During the study, pH value in the river water was 6.37, which is within the permissible limit stated by MOH (6.50 to 9.0). According to [3], the pH of river water is near to neutral because the downstream area of Langat River has high level of exposure to seawater. Thus the pH value tend to increase.…”

“…State water authorities are responsible for monitoring water intake by treatment plants. River water quality is measured based on a water quality index (WQI), which is built from six selected parameters, namely, dissolved oxygen (DO), BOD 5 , COD, SS, NH 3 -N, and pH. According to the latest Environmental Quality Report issued by Malaysia's DOE, 34% and 7% of the 473 rivers monitored are slightly polluted and polluted, respectively.…”

“…Pollution is mainly caused by human activities, such as agro-based industries, farming, manufacturing industries, livestock, domestic sewage, and earthwork [2]. Langat River in Selangor is an example of a river basin that has a history of river water pollution associated with these activities [3].…”

A Study on Water Quality From Langat River, Selangor

“…The sources of the Langat River pollution are identified as industrial discharge (58%), domestic sewage from treatment plants (28%), construction projects (12%) and pig farming (2%) [6]. A study from a research showed that major sources of surface water quality variations in Langat River come from industrial effluents, wastewater treatment plants, domestic and commercial areas [7].…”

Species Composition and Abundance of Freshwater Fishes in Selected Rivers of Johor, Malaysia

“…However, 42% of the rivers systems have been classified as polluted, mostly due to surface runoff, discharge of sewage and industrial effluent [2]. As the human population increases, the pressure on the utilization of natural resources increases in tandem.…”