基于综合水质标识指数法的四川西充河水质评价

Assessment of water quality of Xichong River of Sichuan by comprehensive water quality identification index

四川省西充河为严重污染河流,选取溶解氧(DO)、氨氮(NH+4-N)、五日生化需氧量(BOD5)、总氮(TN)、总磷(TP)5项指标年平均值,采用综合水质标识指数法,研究了西充河近10年水质状况随时间变化趋势及水污染特征。2003年至2010年水质级别为劣V类,2011年和2012年水质级别为Ⅳ类,水质标识指数Iwq从2003年的12.459逐渐降低到2012年的4.431。西充河近10年水质状况整体呈好转趋势,但未达到国家规定的Ⅲ级水质标准,水质标识指数Iwq结果表明该好转的速度较慢,西充河水质状况有较大的上升潜力和空间。总氮(TN)和氨氮(NH+4-N)为河流主要污染物,为了达到国家Ⅲ级水质标准,西充河的治理已刻不容缓。

Xichong River in Sichuan Province has been polluted seriously. Method of comprehensive water quality identification index, which selected TN, TP, DO, NH4-N and BOD as indicators, was used to evaluate water quality of Xichong river during 2003 -2012. The results show that water quality from 2003 to 2010 was worse than the V grade of the national standard, from 2011 to 2012 raised to IV grade. Index of water quality identification decreased from 12.459 in 2003 to 4.431 in 2012, implying that Xichong River was improved slowly though still failed to meet the formulated Grade Ⅲ. Monitoring data showed that TN and NH4-N were the main pollutants in the river. More efforts should be made to control the pollution of Xichong River for it to reach the III grade of national water quality standards.