上海市淡水养殖水体中氮、磷的分布研究

Distribution of Nitrogen and Phosphorus in Waters of Freshwater Aquaculture in Shanghai

为查明上海市淡水养殖水体中氮、磷分布现状,选取上海市典型的淡水养殖场进行引水和池塘水质监测。结果表明,上海市淡水养殖水体中总氮、总磷年均质量浓度分别为2.53 mg/L和0.294mg/L;引水和池塘水体中总氮平均质量浓度无显著差异(P>0.05),池塘水中总磷平均质量浓度为0.370mg/L,显著高于引水;不同养殖品种池塘中氮、磷年均质量浓度有所差异,淡水鱼塘中总氮、总磷平均质量浓度最高,凡纳滨对虾塘次之,中华绒螯蟹塘最低;养殖生产使池塘水体中有机态氮、磷在总氮和总磷中的占比以及氨氮在无机氮中的占比较引水均有所增加;引水中总氮在春、冬季含量相对较高,总磷在夏、冬季含量较高。养殖过程中淡水鱼塘中氮、磷含量因有机质的累积在秋季养殖后期较高;凡纳滨对虾塘中氮、磷含量在5月养殖初期相对较高;中华绒螯蟹塘内氮含量因水草的净化作用随养殖进程逐渐降低;70%以上的引水样品水质综合污染指数高于1.0,淡水养殖的引水质量不容乐观。整体上,淡水鱼的养殖显著增加了水体的综合污染程度(P<0.05),凡纳滨对虾和中华绒螯蟹的养殖对水体综合污染程度影响不显著(P>0.05)。

Water quality of inlet water and pond water in representative aquafarms had been monitored in order to investigate the pollution status of nitrogen and phosphorus in freshwater aquaculture in Shanghai.The results showed that the annual average concentrations of total nitrogen（TN）and total phosphorus（TP）were 2.53 mg/L and 0.294 mg/L,respectively,without significant difference in TN concentration between the inlet water and pond water.The annual average concentration of TP was 0.370 mg/L in the pond water,significantly higher than that in the inlet water.The average concentrations of TN and TP in the fish ponds were found to be higher than those in Pacific white shrimp Litopenaeus vannamei ponds,and the minimum in Chinese mitten handed crab Eriocheir sinensis ponds.The proportion of organic nitrogen and organic phosphorus in TN and TP increased as aquaculture proceeded,and the same case in the ratio of ammonium in total inorganic nitrogen.The concentrations of TN in the inlet water were higher in spring and winter than those in the other two seasons,and the phosphorus content increased in summer and winter.Contents of nitrogen and phosphorus in the fish ponds were higher during the late culture period due to the organic matter accumulation.The relative higher concentrations in Pacific white shrimp ponds was observed in the prophase due to higher water fertility.TN concentrations in the Chinese mitten handed crab ponds were decreased gradually during the aquaculture production.There was comprehensive pollution index of over 1.0 in more than 70% of the inlet water,so the quality of the inlet water for freshwater aquaculture in Shanghai was not optimistic.Overall,the freshwater fish aquaculture aggravated the water pollution,while this situation in the Pacific white shrimp and Chinese mitten handed crab ponds was not significant.