乌鲁木齐塔桥湾水库渔业水质分析

2013年5-9月对乌鲁木齐塔桥湾水库渔业水质展开了调查，通过监测酸碱度(pH)、叶绿素a(Chl-a)、亚硝酸盐氮(NO2--N)、氨氮(NH4+-N)、非离子氨(NH3-N)、高锰酸盐指数(CODMn)、总氮(TN)、总磷(TP)、溶解氧(DO)、水温(T)、蓄水量(V)共计11个项目，分析水库水质。利用相关性分析、单项污染指数、综合营养状态指数及主成分分析，对乌鲁木齐塔桥湾水库渔业水质的质量现状和污染特征进行研究。结果显示，水质呈弱碱性，pH月均值在7.45~8.59；NH3-N、NH4+-N、TN、CODMn、TP均严重地超过渔业水质标准限值；月均氮磷比为20.31~156.60:1，月均综合营养指数为58.9~78.3，水体一直处在氮元素过剩和富营养状态，营养盐和有机物是塔桥湾水库的主要污染物。水库多项水质因子之间存在密切的相关性，其中营养盐TN、TP、NO2--N、NH4+-N 两两之间的相关系数为0.742~0.890，蓄水量与TN、TP、NO2--N、NH4+-N、NH3-N、pH、Chl-a的相关系数在0.585~0.943。主成分分析表明，营养盐和有机物对水质的影响随时间而改变，5－8月，营养盐对水质的影响作用减弱，有机物、水温和溶解氧对水质的影响作用增强。积累的数据为新疆渔业养殖提供了资料，为渔业主管部门加强水产品质量安全源头监管提供参考，并对我国现有渔业水质标准中的氨氮和非离子氨指标规定进行了探讨。

Fishery Water Quality in the Taqiaowan Reservoir of Urumqi, Xinjiang

The statistical analysis report of Xinjiang fisheries in 2013 showed that reservoir breeding areas were the first among the Xinjiang fisheries. Along with other functions, the small and medium-sized reservoirs located in the suburbs of Xinjiang cities generally produce fish. However, direct discharge of untreated sewage has degraded the water quality of these reservoirs in recent years and only a few studies have been reported on the ecology of reservoir fisheries in Xinjiang. In this study, we investigated the fishery water quality in Taqiaowan Reservoir, a medium-sized reservoir located in the suburb of Urumqi, the capital of Xinjiang Uygur Autonomous Region. From May to September 2013, monthly monitoring of water quality were carried out at three sampling sites in the reservoir. Water samples were collected at 50 cm below the surface water and eleven water quality parameters closely related to fishery production were measured: pH, chlorophyll a (Chl-a), nitrite nitrogen (NO2--N), ammonia and ammonium nitrogen (NH3/NH4+-N), chemical oxygen demand (CODMn), total nitrogen (TN), total phosphorous (TP), dissolved oxygen (DO), water temperature (T) and volume (V). Fishery water quality and pollution characteristics of the Taqiaowan Reservoir were then analyzed by correlation analysis, single pollution index, comprehensive trophic state index and principal component analysis. The water in Taqiaowan Reservoir was weakly alkaline (average monthly pH ranged from 7.45 to 8.59) and levels of NH3,NH4+-N, TN, CODMn and TP far exceeded fishery water quality standards. The average ratio of nitrogen to phosphorus during the investigation ranged from 20.31:1 to 156.60:1 and the comprehensive trophic state index ranged from 59.8 to 78.3. The water body was always eutrophic due to excess nitrogen. Nutrients and organic matter were the primary pollutants in Taqiaowan Reservoir. Correlation analysis shows that there were strong correlations among the water quality parameters with correlation coefficients among TN, TP, NO2--N, NH4+-N ranging from 0.742 to 0.890 and correlation coefficients between water storage and TN, TP, NO2--N, NH4+-N, NH3-N, pH, Chl-a ranging from 0.585 to 0.943. Principal component analysis indicates that the effects of nutrients and organic matter on water quality varied over time. From May to August, the effects of nutrients on water quality were declining, while the effects of organic matter, water temperature and dissolved oxygen were increasing. The evaluation criteria for NH4+-N and NH3-N in the existing fishery water quality standard were also discussed. This water quality study of a highly polluted reservoir has practical significance for fisheries in Xinjiang and provides a reference for managing the quality and security of aquatic products.