Multivariate and spatial methods-based water quality assessment of Chu Tran Valley, Gilgit Baltistan

Abstract Current study was performed to evaluate the physico-chemical, metals and microbial characteristics of the surface water available in Chu Tran valley located in sub-district Shigar of district Skardu, Gilgit Baltistan, Pakistan. A total of 24 water samples were collected and analysed to determine the water quality index (WQI). Multivariate analysis comprising principal component analysis (PCA) and spatial distribution using inverse distance weight (IDW) interpolation were also employed to ascertain the water quality available in the valley and public health concern assessment. The results of WQI comprehended that physico-chemical characteristics of the water samples are excellent. However, the concentration of metals in water samples is higher than recommended WHO standards and public health quality of water supply is not satisfactory; therefore, the water in the valley is unfit of human consumption. Multivariate analysis with PCA technology identified important water quality parameters and revealed that metals and microbial concentrations are major later factors which have significant influence on the water quality. IDW-based spatial distribution indicates that water samples collected from the central part of the valley are highly contaminated with metals and microbial load. This is the region where the major human settlements are located and agricultural activities, domestic dischargers and erosion are the fundamental sources of water pollution. People have no choice except to consume the contaminated water as no other water supply is available and hardly question about the water quality. The study also proved that combination of WQI, PCA and IDW is effective and promising tools for surface water quality assessment in other areas in order to get accurate results for public health monitoring. It is recommended that the sources of contaminations can be further explored to reduce the pollution load of the surface water of Chu Tran Valley that might be helpful in the promotion of sustainable ecotourism.