Groundwater Pollution Characteristics And Health Risk Assessment In A Certain Area

Groundwater is an indispensable resource in the world.Because of its abundant reserves,transparent natural filtered water,and easy excavation,it can meet the domestic water used in many manufacturing,agricultural products,and residents.Groundwater is used as a major drinking resource in more than half of urban areas and in most rural areas in China.The daily behavior of people and related industries will affect the quality of groundwater.The agricultural industry is over-fertilized during planting,the chemical industry’s waste-water during production,and the irrational disposal of residents’daily garbage will affect the quality of groundwater.Because the groundwater is at the bottom,it is difficult to solve it artificially when its water quality is affected,and its self-cleaning power is poor,so it takes a long time to recover,during which the lives of residents are endangered.The research object of this paper is rural areas in north of China.The water quality of more than 140 villages and towns using groundwater drinking water is used as samples.The inductively coupled plasma mass spectrometer is used to determine the p H,temperature,dissolved oxygen,and whether the samples contain metal and non-metal elements.These values are used to analyze the groundwater quality in the rural areas.By combining the two models of the single pollution index method and Nemerow index method with water quality health hazard assessment,more authoritative and in-depth detection Whether groundwater in the area is carcinogenic.The main results are as follows:（1）Data of groundwater p H,temperature,electrical conductivity,dissolved oxygen,total water hardness,and nitrate concentration in the sample area are 7.02-9.02,12.1℃-28.5℃,150-1290μS/cm,0.28-3.38mg/L,77-545mg/L,0.24-178mg/L,in which the total hardness of the water in the sample area is greater than the type III data range indicator specified in the"Groundwater Quality Standard",which exceeds the indicator by nearly 40%,especially in the middle and north-central areas of the sample area obvious.（2）The concentrations of chloroform,fluorine,benzene,toluene,dichloromethane,benzo（a）pyrene,molybdenum,barium,antimony,lead,and copper in the groundwater of the study area are 0-7.08μg/L,0.16-405μg/L,0-2.76μg/L,0-5.43μg/L,0.02-6.67μg/L,0-1.82μg/L,0-33.4μg/L,0-339μg/L,0-2.70μg/L,0-8.10μg/L,0-69.4μg/L.In terms of metal elements,the content of each element is lower than the Class III water quality standard of Groundwater Quality Standard.In terms of non-metallic elements,the content of benzo（a）pyrene and nitrate in the groundwater is relatively high,and the content of benzo（a）pyrene in 57%of the sampling points is higher than Class III water,and the water quality is poor.The content of nitrate in nearly 70%of the sampling points is within the standards of Class IV and V water,and the water quality is extremely poor.（3）Only nitrate in the groundwater in the study area exceeded the standard in some areas.There were no indicators of exceeding the standard in p H,total hardness,nitrate,iron,manganese,copper,zinc,aluminum,etc.groundwater pollution occurred in all indicators.Under comprehensive evaluation,the results are all in Class III or lower,which indicates that the groundwater quality in the research area is not significantly polluted under the comprehensive influence of the detection indicators,and the quality of groundwater is still good.The non-carcinogenic risk range values of fluorine,copper,arsenic,and nickel in groundwater in the study area are 7.52E-06～3.41E-03,and the non-carcinogenic risk is ranked as arsenic>nickel>copper>fluorine,and the non-carcinogenic risk values are all within 1 and The non-carcinogenic risk is within the acceptable range of the human body,and it can also be ignored.The carcinogenic risk value of arsenic in groundwater is 6.8×10^-8,which is an acceptable risk level and is in a controllable range.