THE EFFECTS OF INDUSTRIAL LAND USE ON THE BAGMATI RIVER BASIN IN KATHMANDU, NEPAL

A new international collaboration between the University of Northern Iowa (UNI), USA and Tribhuvan University (TU), Nepal was initiated in 2015. The project is funded by the U.S. National Science Foundation. The project deals with the environmental assessment of Bagmati River in Kathmandu Valley, Nepal. The capital city of Kathmandu, which is home for 1.7 million people, is located on the banks of the Bagmati River. The river has turned into a highly polluted water body due to the dramatic increase in population and urban development in the valley in recent decades.

Ten (10) sites along the Bagmati River were sampled twice a week from middle of May through late July in 2015. Water samples were analyzed for temperature, pH, total dissolved solids (TDS), conductivity, dissolved oxygen (DO), total suspended solids (TSS), turbidity, E. coli, total coliform, biochemical oxygen demand (BOD), nitrate, total phosphorus (TP), and chloride. Stream sediments were analyzed for metals, including As, Mg, Pb, Cu, Fe, Ni, Cr, Cd, Mn, Zn, Co, and Al. The results showed extremely deteriorated water quality conditions in the river. The average TDS value increases from 22 mg/L in Sundarijal (near source) to 402 mg/L near Kalimati further downstream (mid-town Kathmandu). Similarly, TSS increases from 40 mg/L to 275 mg/L, respectively. Although DO in the upper reaches (Sundarijal and Jorpati) were recorded between 6 and 7 mg/L, the values quickly dropped below 2 mg/L in all sites in the city areas downstream. E.coli increases from 8,000 MPN/100 mL in Sundarijal to 231,000 MPN/100 mL in the Kalimati area. The high levels of E. coli and very low DO in the stream water along the urbanized section showed influence of direct sewage disposal. Lack of wastewater treatment facilities has been the major constraint in the management of Bagmati River. Industrial effluents and wastes from the hospitals are also adding to the level of pollution. Other problems include use of agricultural fertilizers and pesticides, discharge from toilets, and wastes deposited by slaughter houses. Metals of health risks are currently being studied. For example, arsenic in drinking water has been a widely publicized health hazard in Southeast Asia. Metallic arsenic is used in car batteries, production of pesticides, treated wood products, herbicides, and insecticides.