贵州草海城郊混合区农田沟渠氮磷含量及分布特征

The Contents and Distributive Characteristics of Nitrogen and Phosphorus in Farmland Ditches of the Suburban Mixed Area near to Caohai Natural Reserve,Guizhou

采集了贵州草海城郊混合区农田沟渠水样进行化学分析,以研究其氮磷含量及分布特征。结果表明:(1)农田沟渠水中TN质量浓度为3.30～14.35(7.06±2.44)mg/L,NH4+-N为0.05～11.92(3.77±2.72)mg/L,TP为0.06～2.97(0.49±0.39)mg/L,平均质量浓度均超过地表Ⅴ类水质标准,养殖废水和生活污水的直接排放是导致污染的重要原因;(2)随着距离城区的远近氮磷浓度变化趋势显著,从远区到近区农田沟渠水中氮磷的平均质量浓度逐渐升高,污染源不同是导致沟渠水质差异的主要因素;(3)农田沟渠对氮磷具有一定的截留作用,沿水流方向氮磷的质量浓度呈降低的趋势,对TN、NH4+-N和TP截留率分别为25.2%、53.8%和14.3%。

The water samples were collected from farmland ditches in the suburban mixed area near to Caohai natural reserve for the investigation of nitrogen and phosphorus contents as well as their distributive characteristics. The results showed that the concentration of TN NH4^＋ -N and TP were 3.30 -14.35 （7.06 ±2.44） mg/L, 0.05 - 11.92 （3.77 ±2.72） mg/L and 0.06 - 2.97 （0.49 ±0.39） mg/L, respectively, in the water of farmland ditches, and the average values were worse than that of grade V water, which was chiefly ascribed to the direct discharge of sewage. Nitrogen and phosphorus concentrations differed depending on the distances between sampling sites and the city, and the cause for the quality variation of ditch water was also due to the pollution source. Farmland ditches might retain nitrogen and phosphorus, and the retention rates of farmland ditches for TN, NH4^＋ -N and TP were 25.2% , 53.8% and 14.3% , respectively.