长江经济带淡水养殖污染负荷特征分析

Pollution load characteristics of freshwater aquaculture in the Yangtze River Economic Belt

采用系数法对我国长江经济带地区11个省(市)淡水养殖的蛋白质产量及氮磷排放总量进行核算,由此计算单位蛋白产出污染物排放强度及单位面积污染物排放强度;利用环境库兹涅茨曲线模型(EKC)分析淡水养殖蛋白质产出与单位蛋白产出的污染物排放强度之间的关系。结果显示:(1)1991年至2019年期间,长江经济带淡水养殖蛋白质产出、总氮和总磷排放量均呈现快速增长的趋势;湖北、江苏、江西和湖南4个省份淡水养殖总氮、总磷的排放总量较高;浙江省单位面积污染物排放强度最高;(2)各省(市)单位蛋白质产出的总氮、总磷排放强度均呈现缓慢增加的趋势,显示长江经济带淡水养殖总体上趋于对环境影响更严重的水产品种;(3)肉食性水产品的总氮、总磷排放量最高,且持续增加;杂食性水产品总氮、总磷排放量其次,呈现先增长后下降的趋势;滤食性水产品总体污染负荷呈现持续下降趋势;植食性水产品总氮、总磷排放量最低;(4)Kuznets回归模型结果显示,随着淡水养殖强度增加,单位面积蛋白质产出对单位蛋白产出的总氮排放量具有正向促进作用;对单位蛋白产出的总磷排放量则呈现“倒U型”关系,且Moran’s I指数显示各省总磷排放强度空间自相关性更高,呈现相互影响的趋势更明显。回归结果表明,随着渔业经济增长,淡水养殖结构变化等因素对氮污染的影响更大,需要加大氮污染防治的相关研究。

Quantity and intensity of the nitrogen and phosphorus pollutants from freshwater aquaculture in the Yangtze River Economic Belt from 1991 to 2019 were calculated in this paper.The correlation between the pollutants and the economic growth was also analyzed with Kuzents models.The results showed that:(1)The protein output,total nitrogen(TN),and total phosphorus(TP)from freshwater aquaculture increased steadily,especially in Hubei,Jiangsu,Jiangxi,and Hunan Province.The pollutant output per unit area was the highest in Zhejiang Province.(2)The emission intensity of TN and TP per unit protein output showed a slow increasing trend,which indicated that the freshwater aquaculture in the Yangtze River Economic Zone tended to the aquatic products with more serious environmental impact.(3)The TN and TP emissions of carnivorous aquatic products were the highest and increased continuously,the TN and TP emissions of omnivorous aquatic products were the second,increasing first and then decreasing,the total pollution load of filter-feeding aquatic products showed a decreasing trend,and the TN and TP emission of herbivore aquatic products was the lowest.(4)The results of Kuznets model showed that the protein output had a positive effect on the TN emission per unit area with the increase of freshwater aquaculture intensity,on the other hand,the TP emission per unit protein was inversely u-shaped,and Moran’s I index indicated that the spatial autocorrelation of TP emission intensity was higher and the mutual influence was more obvious.The regression results show that with the increase of fishery economy,the change of freshwater aquaculture structure and other factors have a greater impact on nitrogen pollution.More studies should be considered in nitrogen pollution abatement in aquaculture in the Yangtze River Economic Belt.