摘要
淮南矿区潜水位高,采煤沉陷区范围广、面积大、水质监测数据缺失,水环境问题较突出,开展大尺度的沉陷区水质评价及污染因子识别,对于区域水环境治理工作意义重大。通过采集、测试研究区175个样点的水样,采用内梅罗污染指数法对沉陷区水域进行水质评价,采用综合营养状态指数法进行水体富营养化状态评价。结果表明:(1)开放型沉陷区Cu、As和Cr的水质评价等级为优良,DO、COD、NH_(3)-N、Hg、F^(-)评价等级为良好,TN、TP评价等级为较好。封闭型沉陷区,对标地表水Ⅲ类标准,Cu、Cr水质评价等级为优良,NH_(3)-N、Hg、As、DO为良好,COD、TN为较好,TP、F^(-)为较差;对标地表水Ⅴ类标准,NH_(3)-N、Hg、As、Cu、Cr的评价等级为优良,DO、COD、TP、TN为良好,F^(-)为较好。(2)研究区综合营养指数范围为40~90,平均68.61,属于中度富营养,沉陷区水体营养水平适中。175个水样中,轻度富营养占比8.57%,中度富营养占比51.43%,中营养占比2.29%,重度富营养占比37.71%。(3)对标《地表水环境质量标准》,常规指标中DO、NH_(3)-N超过Ⅴ类占比极小,而COD、TP、TN超过Ⅴ类占比较大;研究区所有水域均无重金属超标现象,测试结果极佳;无机阴离子指标F^(-)超过Ⅴ类占比较大。开放型沉陷区水域水质状况整体优于封闭型。对于开放型水域,张集、潘一沉陷区TP、F^(-)指标均较差;对于封闭型水域,潘一、潘三、顾桥、顾北、张集沉陷区TP指标较差,F^(-)污染分布呈现地域特征,淮河以北普遍较差,淮河以南普遍优良。所有水域的Cr、Cu、Hg、As、NH_(3)-N、TN、COD、DO指标均处于“优良-较好”区间内;开放型水域的F^(-)、TP指标均处于“优良-较好”区间内;封闭型水域中潘集片区F^(-)和凤台颍上片区TP均处于“较差”区间内;区域污染程度表现为凤台颍上片区>潘集片区>老矿区。(4)从保护煤矿区生态环境的角度出发,综合考虑2种污染因子识别方法的特性,最终确定淮南矿区采煤沉陷区污染因子有COD、TP、TN和F^(-)。本次水质评价工作识别了淮南采煤沉陷区污染因子,为地方政府和企业制定生态环保决策提供重要数据支撑。
Huainan mining area is characterized by a high phreatic water level,as well as a wide range and large area of coal mining subsidence areas,with the water quality monitoring data missing and prominent water environment.Therefore,the evaluation of water quality monitoring and identification of pollution factors in large subsidence area is of great significance to regional water environmental governance.Specifically,the water quality of the subsidence area was evaluated with the Nemerow pollution index method by testing the water samples collected from 175 sampling points in the study area.Meanwhile,the eutrophication state of water bodies was evaluated with the comprehensive trophic status index method.The results show that:(1)For the open subsidence areas,the water quality level is evaluated to be excellent in terms of Cu,As and Cr,good in terms of DO,COD,NH_(3)-N,Hg and F^(−),and relatively good in terms of TN and TP.For the closed subsidence area,the water quality level is evaluated to be excellent in terms of Cu and Cr,good in terms of the NH_(3)-N,Hg,As and DO,relatively good in terms of COD and TN,and poor in terms of TP and F−according to Level-III standard of surface water.However,the water quality level is evaluated to be excellent in terms of NH3-N,Hg,As,Cu and Cr,good in terms of DO,COD,TP and TN,and relatively good in terms of F−according to Level-V standard of surface water.(2)The comprehensive trophic status index of the study area is ranged within 40‒90,and the average trophic status index is sized 68.61.Therefore,the study area is in moderate eutrophication,which shows that the water body in the subsidence area is at moderate trophic level.Among the 175 water samples,8.57%of the samples are in light eutrophication,51.43%in moderate eutrophication,2.29%in medium nutrition,and 37.71%in severe eutrophication.(3)According to the Standard for Environmental Quality of Surface Water,few samples have DO and NH_(3)-N exceeding the level-V value,but most samples have COD,TP and TN exceeding the level-V value,and there are no excessive heavy metals in all waters of the study area,with excellent test results.Besides,a large number of samples have the inorganic anion index F−greater than the level-V value.Generally,the water quality of open subsidence area is better than that of the closed subsidence area.(4)For the water,TP and F−are poor for Zhangji and Panyi subsidence areas.For the closed water,the TP of Pan Yi,Pan San,Guqiao,Gubei and Zhangji subsidence areas are poor.The distribution of F^(−)pollution shows the geographical characteristics,which is generally poor in north of Huai River and good in south.The indexes of Cr,Cu,Hg,As,NH_(3)-N,TN,COD and DO in all waters are in the“excellent-relatively good”range.The F−and TP indexes of all the open subsidence areas are also in the“excellent-relatively good”range.But the F^(−) of the closed water in Panji area and TP in Fengtai-Yingshang area are in the“poor”range.The regional pollution level is shown as Fengtai-Yingshang area>Panji area>old Mining area.(4)In order to protect the ecological environment of coal mining area,the pollution factors of coal mining subsidence area in Huainan mining area are determined to be COD,TP,TN and F^(−),with comprehensive consideration to the characteristics of two identification methods of pollution factors.The results provide important support for local ecological and environmental protection.
作者
胡林
陈永春
徐燕飞
李兵
王锦
安士凯
陈晨
孙宏杰
苗伟
HU Lin;CHEN Yongchun;XU Yanfei;LI Bing;WANG Jin;AN Shikai;CHEN Chen;SUN Hongjie;MIAO Wei(National Engineering Laboratory for Protection of Coal Mine Eco-Environment,Huainan 232001,China;Anhui Province Engineering Research Center of Coal Mining Green Low-Carbon Development,Huainan 232001,China;National Research Institute of Engineering Technology in Coal Mining,Huainan 232001,China)
出处
《煤田地质与勘探》
EI
CAS
CSCD
北大核心
2023年第11期83-91,共9页
Coal Geology & Exploration
基金
安徽省自然科学基金面上项目(2208085ME123)
安徽省自然资源厅公益性地质项目(2021-g-1-7)。
关键词
采煤沉陷区
高潜水位
水质评价
污染因子识别
富营养化评价
淮南矿区
mining subsidence area
high phreatic water level
evaluation of water quality
identification of pollution factors
eutrophication evaluation
Huainan mining area
