东海无机氮排海通量年际变化估算

通过系统收集和推算1980～2005年东海几种入海污染源的无机氮数据(河流、排污口、陆源面源、大气沉降和海水养殖)基础上,研究估算了东海无机氮的入海年际通量变化情况.结果表明,自20世纪80年代初至21世纪初,东海无机氮入海通量总体呈现上升趋势:由20世纪80年代初的8.8×105t.a-1左右逐渐增加到本世纪初的2.6×106t.a-1左右,年平均增长率为4.3%.长江作为东海最大入海河流,其无机氮排海通量占河流排海海通量的76.5%,排放量由80年代初的4.0×105t.a-1上升到80年代中期的6.2×105t.a-1,后保持在此值上下浮动,然后从90年代开始快速上升到本世纪初的1.8×106t.a-1.东海无机氮主要来源是以入海河流为主的陆源排放,大约为总量的79%,其中河流、排污口和陆源面源分别为73%、4%和2%.除陆源外,大气沉降约为18%,海水养殖约为3%.

Estimation of the Flux of Inorganic Nitrogen Flowing into the East China Sea

The flux of inorganic nitrogen flowing into the East China Sea was estimated based on the systematic analysis of all the pollution sources from 1980-2005.The result showed that the flux of inorganic nitrogen had been increasing from the early 1980s to the early 21^st century. In detail, the flux was about 8.8×10⁵ t·a^-1 in the early 1980s, and increased to about 2.6×10⁶ t·a^-1 in the early of 21^st century. The annual increasing rate was about 4.3%, and the mean flux was 1.8×10⁶ t·a^-1. The flux of inorganic nitrogen of Yangtze River had also been increasing from early 1980s to the early 21^st century. In detail, the flux was 4.0×10⁵ t·a^-1 in the early 1980s, and increased to about 6.2×10⁵ t·a^-1 in the middle 1980s, and was then kept at this value to the end of 1980s. After that, the flux value increased quickly from the early 1990s to 1.8×10⁶ t·a^-1 in the early 21^st century. Of all the sources, the proportion of land-source inorganic nitrogen was the largest, which was about 79%, among which, the river-source, the sewage-source and the non-point source accounted for 73%, 4% and 2%, respectively. Besides the land-source, the air-source and the mariculture-source accounted for 18% and 3%. The proportion of flux of Yangtze River in the river source was 76.5%.