| After the Three Gorges Reservoir was storage water in June 2003, organic contamination, nutrient and biomass were determined in 13 tributaries of Three Gorges Area in three seasons. Potassium permanganate index, chemical oxygen demand (COD), ammonia nitrogen (NH+4-N), total nitrogen (TN), total phosphorus (TP) and chlorophyll a (Chl-a) value are 0.20-5.91 mg·L-1, 4.06-30.2 mg·L-1, 0.542-7.44 mg·L-1, 0.034-2.83 mg·L-1, 0.010-0.449 mg·L-1 and 1.02-128 mg·m-3 respectively. The water body of tributaries is polluted at various levels. The concentration of TN is abundant. The rate of TN and TP showed that a part of tributaries eutrophication are limited by TP. Low concentration of Chl-a was in tributaries water body except Zhuxi river. Trophic states of tributaries were oligotropher to mesotropher. Utilizing the method of between-subjects effects tests, it indicated that spatial and seasonal distribution of nutrient factors is different in diverse seasons. The correlation of nutrient, organic contamination and Chl-a were researched. It indicated there was a significant positive correlation among Chl-a, nutrient and organic contamination. Fluxes load of nutrient and organic contamination was calculated by discharge and concentration of each tributary. It indicated that flux load of nutrient and organic contamination was mainly controlled by discharge. The flux load in flood season is higher than normal and dry season. The nutrient fluxes load of COD, potassium permanganate index, NH+4-N, TN and TP are 1 172-6 701 g·s-1, 380-1 875 g·s-1, 40.1-172 g·s-1, 249-922 g·s-1 and 9.97-50.5 g·s-1 respectively. Pollution of tributaries in Three Gorges Area should be noticed. |
