嘉陵江水体中COD_(Mn)和BOD_5的季节变化及输出

Seasonal Variation and Output of COD_(Mn) and BOD_5 in the Jialing River

于2006年1月～2006年12月在嘉陵江北碚段每月采集水样1次,分析水体CODMn、BOD5的季节变化和垂直分布.研究结果表明,2006年嘉陵江的CODMn、BOD5含量呈明显季节变化,其变化规律为丰水期>平水期>枯水期.丰水期、平水期、枯水期CODMn的含量范围分别为:2.5～7.0,2.1～2.8,1.9～2.5mg/L,BOD5的含量范围分别为0.8～2.1,0.7～1.9,0.8～1.1mg/L.CODMn、BOD5与径流量之间都存在显著正相关关系,表明嘉陵江沿岸有机物污染比较严重,且主要受到面源污染的影响.枯水期,平水期,丰水期颗粒态CODMn含量占CODMn含量的范围变化较大,分别为:3.9%～17.2%,4.8%～28.1%,8.9%～60%,颗粒态CODMn与流量之间呈显著正相关关系,表明嘉陵江沿岸水土流失比较严重.垂直分布上,污染物2个层次变化不显著,未出现分层现象.CODMn、BOD5通量也呈明显季节变化,7月份的通量明显大于其它月份,与径流量在99%的置信水平上呈显著相关关系.与2003、2004年三峡库区的工业废水、城市废水排放量相比,CODMn、BOD5通量都明显偏大.

Through mensal sampling and analysis in the Jialing River from January 2006 to December 2006, the seasonal and vertical variation of concentration of biochemical oxygen demand （BOD5） and permanganate index of oxygen demand （CODMn） were investigated. The results showed that the seasonal variation of concentration of CODMn and BOD5 in the Jialing River in different seasons were both in the order of high- flow period 〉 mean-flow period 〉low-flow period The concentration of CODMn in low-, mean- and high- flow periods was 2. 5--7.0 mg/L, 2. 1 --2.8 mg/L and 1.9--2.5mg/L, respectively, while that of the concentration of BODs in low-, mean- and high-flow periods was 0.8--2.1 mg/L, 0.7--1.9 mg/L and 0.8 --1.1 mg/L, respectively. CODM, and BOD5 were in significant positive correlation with water discharge, which indicated that the Jialing River was seriously contaminated by organic pollutants and that it was affected mainly by non-point source pollution. Particle CODMn rate in total CODM. in low-, mean- and high- flow periods was in the range of 3.9 -- 17.2%, 4.8 -- 28.1% and 8.9%-60%, respectively. Particle CODMn was positively correlated with water discharge, indicating serious soil erosion on the banks of the Jialing River. The vertical variation of CODMn and BOD5 was not notable and organic pollutants were not layered. Seasonal variation of flux of CODMn and BOD5 was also revealed in the Jialing River, and the flux of CODMn and BOD5 in July was higher than in other months. Flux of CODMn and BOD5 was in a marked positive correlation with water discharge （p〈0.01）. Compared with CODMn and BOD5 in industry pollutant load and domestic sewage load in 2003 and 2004, flux of CODMn and BOD5 in the Jialing River increased significantly in 2006.