The characteristics and evaluation of water pollution in Ganjiang Tail River

The water quality in Ganjiang River has an important impact on the ecological environment of Poyang Lake, because Ganjiang River is an important water supply of Poyang Lake. In this paper, the electrical conductivity (ED), turbidity (NTU), suspended solids (SS), total phosphorus (NP), total nitrogen (NT), ammonia nitrogen (NH₄-N), nitrate nitrogen (NO₃-N), and chemical oxygen demand quantity (COD) have been considered as indicators of water quality while performing an assessment of water in Ganjiang River. We evaluated and analyzed comprehensively the quality of surface and underground water by using the Water Quality Identification Index Method. The sample water was retrieved every 50 days from eight monitoring points located in three sections of downstream Ganjiang River in Nanchang city; the study was conducted from September 10, 2015 to June 1, 2016. The results indicate that the pollution index of northern, central, and southern tributaries in Ganjiang River downstream are 3.807, 3.567, and 3.795, respectively; these results were obtained by performing the primary pollutants quality identification index method (PP-WQI); the pollution index for the same tributaries was found to be 3.8077, 3.5003, 3.7465, respectively when we performed comprehensive water quality identification index method (CWQI). The water pollution grades are between level 3 and level 4. The main pollutants are COD, TN, and SS; moreover, there is a linear relationship between the pollution index in groundwater and surface water. The water quality is the best in the central branch, and worst in the south; the water quality is moderate in the north. Furthermore, the water of upstream is better than that of downstream. Finally, the water quality is worst in summer but best in winter.