Assessment of Water Quality and Ecological Risk in the Phalgu River, Gaya Bihar, India

The Phalgu River in Gaya, Bihar is an important seasonal river system that supports domestic, cultural, and agricultural activities. In recent years, anthropogenic pressures such as sand mining, urban discharge, and agricultural runoff have significantly influenced river water quality. This study evaluates the physicochemical characteristics of the Phalgu River and assesses ecological risk using indices such as Water Quality Index (WQI), Heavy Metal Pollution Index (HPI), and Ecological Risk Index (ERI). Water samples were collected from multiple sampling stations during pre‑monsoon and post‑monsoon seasons. Parameters including pH, dissolved oxygen, turbidity, total dissolved solids, electrical conductivity, and selected heavy metals were analyzed using standard laboratory procedures. Results indicate noticeable spatial and seasonal variations in water quality. Mining‑affected zones exhibited higher turbidity, conductivity, and metal concentration compared with relatively undisturbed sites. The findings highlight the growing influence of anthropogenic activities on river health and emphasize the need for sustainable river management strategies.