电解锰产业集聚区河流锰污染演变趋势和时空分布特征

松桃河流域是我国锰产业最为集中的区域之一,资源开发和利用形成的污染严重。通过对松桃河电解锰产业集聚区流域2015—2019年的8个典型断面的总锰监测数据的分析,用秩相关系数法探究了河流锰污染总体变化趋势,并用系统聚类分析法分析了河流锰的时空分布特征,结合聚类结果对污染趋势做进一步分析。秩相关系数分析结果表明,近年来松桃河锰产业集聚区流域的上游水质较好且稳定,而中游污染严重,干流均值超过地表水环境质量标准值(0.1 mg·L^-1)3—7倍,下游水质有所恢复,流域主要断面锰浓度总体呈下降趋势;时间聚类分析表明,流域内河流锰污染的年内分布主要特征为丰水期(雨季)和枯水期(旱季)浓度较高而平水期相对较低;空间聚类结果显示,流域内河流锰污染呈现出中游支流>中游干流>下游和上游的特征,两条支流道水河和老卜茨小溪对中游相应区段的贡献率较大,分别为41.2%和23.5%;聚类结果分析显示,降雨、渣库分布和渗漏、水文地质条件和支流汇入是影响流域内河流锰浓度的重要因素;结合聚类结果的污染趋势分析得出,中游和下游的水质在枯水期和丰水期的年度变幅较大,但在2017年以后呈现明显的下降趋势,结果反映了期间政府进行综合整治的效果和流域污染源排放的随机性。

Variation trend and spatio-temporal distribution of river manganese pollution in the cluster area of electrolytic manganese industry

Songtao River basin is one of the most concentrated areas of manganese industry in China,pollution caused by resource exploitation and utilization is serious.According to the total manganese monitoring data of 8 typical sections in Songtao River basin of the cluster area of electrolytic manganese industry from 2015 to 2019,we analyzed the general trend of river manganese pollution in Songtao River basin by rank correlation coefficient method,and the temporal and spatial distributions of manganese in rivers were analyzed by systematic clustering analysis,then combined with the clustering results to make a further analysis of the pollution trend.The rank correlation coefficient analysis results show that,in recent years,the water quality in the upper reaches of the basin was good and stable,but the midstream were seriously polluted,and the average concentration of manganese in the trunk stream was 3 to 7 times higher than the Environmental quality standard value for surface water(0.1 mg·L^-1),the water quality had recovered downstream,the manganese concentration in the main section of the basin had showed a decreasing trend.Time clustering analysis showed that,the annual distribution of river manganese pollution in the basin was characterized by high concentration in wet season and dry season while low concentration in normal season.The spatial clustering results showed that,the river manganese pollution in the basin was characterized by the midstream tributary>the middle reaches>downstream and upstream,the two tributaries,Daoshui river and Laobuci stream,contributed more to the corresponding section of the middle reaches,the respective contribution rate was 41.2%and 23.5%.The analysis of the clustering results showed that rainfall,distribution and leakage of slag reservoir,hydrogeological conditions and inflow of tributaries were the important factors affecting the river manganese concentration in the basin.The pollution trend analysis combined with the clustering results showed that,the annual variations of water quality in the midstream and downstream were large in the dry seasons and wet seasons,but showed a significant downward trend after 2017,the results reflected the effect of comprehensive improvements by the government and the randomness of pollutant discharge in the basin.