古泊善后河水质污染特征及污染来源调查

以2016—2020年古泊善后河国家和省级地表水监测网水质例行监测数据为依据,采用水质指数法(WQI)对古泊善后河水质污染状况进行综合评价;基于水质评价结果,选取影响最大的两项指标COD_Mn和TP,于2020年10月对古泊善后河开展加密监测,调查分析污染来源。结果表明,2016—2020年古泊善后河水质波动变化较大,汛期降雨对水质下降影响明显,COD_Mn、TP、COD_Cr、氟化物和BOD₅是影响古泊善后河水质的主要指标;加密监测期间,古泊善后河干流水质COD_Mn和TP指标浓度分别升高28.9%、38.3%,其中宿迁段升幅显著高于连云港段;支流水质超Ⅲ类比例为22.9%,劣Ⅴ比例为6.3%;部分乡镇生活污水直排和持续降雨将农田中高浓度污染物冲刷进河流支浜,是导致水质下降的主要原因。

Investigation and Analysis of Water Quality Pollution Characteristics and Pollution Sources in Guboshanhou River

Based on the routine water quality monitoring data of national and provincial surface water monitoring network of Guboshanhou River from 2016 to 2020,the water quality pollution status of Guboshanhou River was comprehensively evaluated by water quality index method(WQI).Based on the results of water quality evaluation,COD_Mnand TP,which have the greatest impact,were selected to carry out intensive monitoring of the Guboshanhou River in October 2020 to investigate and analyze the pollution sources.The results showed that the water quality of Guboshanhou River fluctuated greatly from 2016 to 2020.Rainfall in flood season has a significant effect on the water quality decline.COD_Mn,TP,COD_Cr,fluoride and BOD₅are the main indexes affecting the water quality of Guboshanhou River.During the intensive monitoring period,COD_Mnand TP concentrations increased by 28.9%and 38.3%,respectively,and the increase rate in Suqian section was significantly higher than that in Lianyungang section.The percentage of tributary with water quality over classⅢwas 22.9%,the percentage of that over classⅤwas 6.3%.Direct discharge of domestic sewage in some towns and villages and continuous rainfall wash high concentration of pollutants from farmland into river branches,which is the main reason for the decline of water quality.