太湖流域江苏地区代表性水产养殖排污系数测算研究

为合理评价水产养殖对环境的影响,选取太湖流域典型地区12个养殖池塘和养殖围网,包括淡水池塘养殖中华绒螯蟹、草鱼和翘嘴红鲌,网围养殖中华绒螯蟹、鲢鳙等5种养殖模式和养殖品种,采用现场监测及物料平衡相结合的方法对水产养殖中总氮、总磷、铜和锌等污染物的排污系数进行系统定量研究。结果表明,物料平衡法计算下的排污系数因养殖品种和养殖模式的不同存在较大差异,即使同一养殖模式下的同一主要养殖品种,因配养情况的不同得出的排污系数也相差很大。围网养殖中华绒螯蟹,套养其他鱼类的比例在30%~60%时,总氮、总磷、铜、锌的排污系数均值分别为16.80、2.80、0.002 0、0.026 1 kg·t~(-1);如不套养或少量套养(套养比例10%),总氮、总磷、铜、锌的排污系数均值分别为90.03、41.39、0.036 5、0.219 8 kg·t~(-1);网围养殖鲢鳙的排污系数为负值。对池塘养殖模式,采用现场实测和物料衡算两种方法同时进行测算,物料衡算法计算下的排污系数远大于现场实测法。研究结果结合渔业统计数据,可核算区域水产养殖污染负荷。在水产养殖过程中,要充分利用鱼、螺、草、藻的物质循环关系,建立一种良好的生态养殖模式,达到经济效益和环境保护双赢的目的。

Study on calculation of representative aquaculture pollution discharging coefficients in the Taihu Lake basin within Jiangsu Province

In order to reasonably evaluate the influence of aquaculture on the environment,six aquaculture ponds and six purse seines in typical areas of Taihu Lake were selected,with four aquaculture species and two aquaculture patterns (Eriocheir sinensis,grass carp,and Erythroculter ilishaeformis in aquaculture ponds;Eriocheir sinensis,silver carp,and bighead carp in purse seines).The aquaculture pollution discharging coefficients for total nitrogen (TN),total phosphorus (TP),copper (Cu),and zinc (Zn) were quantitatively analyzed by the method of field monitoring and mass balance.The results showed that there were great differences in pollution discharge coefficients among the various species and patterns using the mass balance method.Owing to different complementary fishes,the pollution discharge coefficients also varied widely for the same species under the same aquaculture patterns.In seine breeding Eriocheir sinensis,the range of the other fish intercropping proportion was 30% to 60%,and the averages of pollution discharging coefficients of TN,TP,Cu,and Zn were 16.80,2.80,0.002 0,and 0.026 1 kg·t^-1,respectively.Under the circumstance of no or little fish intercropping (the proportion of fish intercropping was less than 10%),the averages of pollution discharging coefficients of TN,TP,Cu,and Zn were 90.03,41.39,0.036 5,and 0.219 8 kg·t^-1,respectively.The pollution discharging coefficients for the silver carp and bighead carp in seine breeding had negative values.Furthermore,the pollution discharging coefficients using mass balance measurement were much higher than those using field monitoring in aquaculture ponds.The results could be used to calculate the regional aquaculture pollution load in combination with fishery statistics.Overall,it is necessary to take full advantage of the material circulation relationships between fish,snail,grass,and algae to establish a good ecological breeding mode for the process of aquaculture,which could lead to a win-win for economic and environmental protection purposes.