Variations of water quality deterioration based on GIS techniques in surface and groundwater resources in and around Vembanad Lake, Kerala, India

Abstract

This study evaluated the status of deteriorating water quality around the Vembanad Lake of Kerala State in India. A total of 40 water samples from lake (L, n = 5), river (R, n = 6), open well (W, n = 26), and bore well (BW, n = 9) and were analysed for major ions as per the APHA methods. Different concentrations of Ca (10–190 mg/L), Mg (2–220 mg/L), Na (10–216 mg/L), K (2–50 mg/L), HCO3 (20–400 mg/L), CO3 (10–50 mg/L), Cl (46.5–950 mg/L), NO3 (0.62–19.75 mg/L), SO4 (20.8–423 mg/L) and PO4 (1.63–16.18 mg/L) represent the three different water types: CaHCO3, NaCl and mixed type of CaNaHCO3. Strong connection between the host rock and groundwater quality indicated substantial water-rock interaction. Factor analysis helped to understand the associations of chemical parameters and their sources. TDS, TH, calcium, magnesium, sodium, potassium and chloride exceeded the BIS (2010) based on desirable drinking water and irrigational quality standards in SE, W, and NW directions due to man-made bunds, industrial wastes, agricultural wastes, household sewages, tourism, lime shell, and sand mining. All point and non-point sources of pollution adversely affected water in and around the Vembanad Lake system and caused by water quality deterioration.