Manganese Pollution In Groundwater And Its Impact On Water Environment In Zhongning Shikong Industrial Park: Assessment And Prediction

Zhongning Shikong industrial park is one of the most characteristic among the ten parks,which made a great contribution to economy and society of Zhongning county. However, therapid development of industrial has also brought a lot of environmental pollution problems.Many factors will lead to the deterioration of the environment, such as not to reduceemissions, poor waste disposal methods, unreasonable discharge measures of sewage, lack ofawareness of the potential risks and mismanagement. Heavy metal pollution is one of themain environmental problems in the study area. In this paper, the heavy metal pollution ofMn was simulated in two types, present conditions and unexpected conditions. The modelwas based on the detailed survey of hydrogeologic conditions and pollution situation of theindustrial park. In addition, the human health risks model of the study area was build toassess the risks of the water quality. After the all research, the main conclusions are asfollows:(1) Unconfined aquifer in the the study area is composed mainly by Quaternarygravel.The thickness of the gravel is between6.08to28.02meters. The thickness of aquiferfrom south to north increasingly thin. The depth of groundwater is generally1to5meters.(2)Recharge sources of groundwater in the study area is canal seepage and infiltration ofirrigation water, which accounted for76.95%of the total recharge. Then there are therecharge of precipitation infiltration, recharge of lateral runoff and seepage of Zhangyugou.The main pathway of discharge of groundwater is runoff and drainage of ditch, whichaccounted for82.24%of the total excretion. Then there are evaporation, artificial mining anddrainage of Zhangyugou.(3) Groundwater pollution in the study area is very serious. The manganese, nitrite, totalhardness and TDS are most seriously, exceeding rates were45.2%,35.5%,35.5%,32.3%.Then the sulfate, ammonia nitrogen, nitrate nitrogen and fluoride exceed the standard slightly,exceeding rates were25.8%,25.8%,22.6%,6.45%. It is worth noting that the concentrationof many components in Zhangyugou is higher than other regions.(4)The human health risk of drinking water was simulated by the EPA model ofAmerican. The assessment results show that138people would have been cancer from1 millions of people because of drinking the groundwater each year. The study area of ShikongTown, west of Huangzhuang, north of Xie Zhuang to Zhangyugou area and Li Ying as thecenter of the eastern region as a high risk area. Region of southwest and south to the YellowRiver region as a low risk area. Half of the area as a high rish area.(5)The groundwater flow model and quality model of the study area were set up by thesoftware of Visual MODFLOW. Then predict the heavy metals pollution of Mn in the studyarea. In the case of various conditions, with the simulation time continue to extend the scopeof manganese pollution continues to expand. But in the next10to20years, the scope ofpollution increased slowly. The next30years to40years, the water quality in the steady state,the scope of pollution not change over time. The stable pollution range was700meters to theeast of Zhangyugou,1500meters to the west of Zhangyugou, south to the Yellow River, northto the outfall of Tianyuan Manganese company.(6)Groundwater pollution of Mn was predicted on the two cases, rainstorm wash awaythe residue field and leaking of residue field. When the residue field was destroyed by theRainstorm, and the slag leaching solution concentration is less than the soil adsorptionequilibrium concentration, its will do not great harmful to the groundwater. But it is hard torestore the entire groundwater environmental situation, maybe need to take several years. Ifthe slag leaching solution concentration is large than the soil adsorption equilibriumconcentration, Once the waste dump has been destroyed, the harm will be very serious, andyou need at least a few decades to basically restore the groundwater environment situation.The pollutant dispersion caused by the leakage of waste dumps is very slow, so it will be notvery serious as soon as we detec the leakage timely and take measures.