对虾养殖对莱州湾氮、磷、COD的贡献

Contribution of shrimp culture to IN, IP and COD in the Laizhou Bay

整理统计了莱州湾主要有机污染物入海通量 ,并于 1 998年 7月 ,调查了莱州湾湾顶部对虾养殖区进、排水中氮、磷及 COD的浓度 ,初步估算出对虾病害发生后 (1 993年 ) ,对虾养殖过程中排入海中 COD的增量平均约为 1 1 73 .4t/a,为黄河年排放量的 0 .5 4% ,小清河年排放量的 0 .2 9% ;无机氮的增量平均为 45 .1 t/a,为黄河年排放量的 1 .79% ,小清河年排放量的 1 .1 0 %。对虾病害发生后(1 993年后 )

In 1993, the epidemic among cultured shrimp broke out. Production of prawn culture in the Laizhou Bay also collapsed to low valley due to the onslaught of virulent diseases. Since then, great changes have taken place in shrimp culture practices. Closed or semi closed culture modes with lower stocking density, less quantity of shrimp feed and volume of renewed water were mostly used. Accordingly, organic rich particulate waste, shrimp faeces, inorganic nitrogen, inorganic phosphorus and dissolved organic discharged directly into the Laizhou Bay decreased in great quantity. In this paper, the discharged flux of major organic pollutants in the Laizhou Bay was sorted out and analyzed statistically. Meanwhile, investigation was carried on in the concentrations of nitrogen, phosphorus and COD in discharged effluent water and receiving water in the culture area in the top of the Laizhou Bay in July 1998. It was estimated preliminarily that the increased amount of COD discharged into the sea was about 1 173.4 t/a on the average in the period from 1993 to present, accounting for 0.54% of discharged amount from the Yellow River and 0.29% of discharged amount from Xiaoqing River; the increased amount of IN was 45.1 t/a on the average which was 1.79% of discharged amount from the Yellow River and 1.10% of discharged amount from Xiaoqing River respectively. Organic pollution caused by shrimp culture along the coast of the Laizhou Bay was much less than that by Yellow River and Xiaoqing River after the epidemic arose in 1993.