In order to clarify the impact of domestic wastewater inflow from Kampala and Ginger cities on Lake Victoria on the coast of Uganda and the Victoria Nile River flowing from Lake Victoria, we measured E. coli in lake and river water, analyzed the origin of fecal contamination using human-associated microbial genetic markers, and investigated the occurrence of antimicrobial-resistant (AMR) E. coli. Although extremely high concentrations of fecal contamination were observed in water bodies where urban wastewater flows into the lake, the level of contamination decreased to a certain level after the wastewater flowed into the huge Lake Victoria. Water intake facilities are located offshore of Lake Victoria, and the level of fecal contamination was low in the water bodies used as water sources. On the other hand, on average, market vegetables were found to contain 10^2 to per 100 g level of E. coli, and positive rates of human-associated genetic markers were also high for some vegetables, suggesting that the use of irrigation water contaminated with urban sewage had an impact on market vegetable contamination. The percentage of antimicrobial -resistant (AMR) E. coli in the E. coli population was low offshore of Lake Victoria, where the tap water is taken, while it reached 40-50% near the drainage canal discharge point, and even at a point about 90 km downstream of the Victoria Nile River, the drug resistance rate hardly decreased, although the concentration itself decreased. This suggests the influence of sewage from large cities on the shore of Lake Victoria, Kampala and Ginger.

Water balance and pollutant loading were investigated for the Nhue-Day River watershed, which is a tributary of the Red River flowing through the northern part of Vietnam. Hanoi, the capital of Hanoi, is located upstream of the basin. About 80% of Hanoi's sewage is discharged after only simple sedimentation treatment in putrefaction tanks, and some of it flows into the Nhue River. Although pollution at the intake point of the Nhue River from the Red River is limited, the water quality deteriorated rapidly through the urban area, the BOD concentration in the river reached a peak of about 80 mg/L around the area where the river left the urban area and entered the suburban area.

On the other hand, as for nitrogen and phosphorus, the pollution loading of nitrogen and phosphorus to soil and water environment almost doubled between 1980 and 2010 in the watershed, and a large part of the increase was derived from agriculture. In addition, due to government policy, the rapidly increasing amount of livestock wastes were actively utilized in agricultural lands during this period, and their input increased about 2.5 times during the above 30 years, making them the main source of nitrogen and phosphorus input next to chemical fertilizers, which were already used in excess in 1980. These indicate that the upstream sewage caused the severe pollution of Nhue River by receiving the sewage. Meanwhile, the nitrogen and phosphorus balance at the watershed level shows a large increase in the loading from agriculture, which is receiving excessive inputs of chemical fertilizers and increasing livestock wastes. The results suggest that the management of resource inputs to agricultural lands and appropriate management of livestock wastes would be important to control nitrogen and phosphorus loadings at the watershed level.