Study On Groundwater Quality Safety In The Zemu River Basin In Pug County

The study gose to the water shortage area in pug county,and the residents are faced with the problems of water quality,water shortage and water sustainability,which seriously threatens the health of local residents and normal production and life.This paper analyzes the natural geographical conditions,geological conditions and hydrogeological conditions of the research area;The distribution characteristics of groundwater chemistry are analyzed by mathematical statistical analysis and GIS technology;The water quality of groundwater is evaluated by single factor evaluation method,nemerow index method and fuzzy comprehensive evaluation method;According to the actual situation,the numerical model of the groundwater solute migration is established.Evaluation results of groundwater quality under two different water quality standards.And according to the evaluation index detection rate,over level rate and the stability to selecte evaluation factor NO3-ion,which is the most to influence the water quality.and TDS,which is correlated with other evaluation factors.They are used as simulate factors.Further to predict and analyze the migration of simulation factors in the next 20 years.The specific results are as follows:?1?The terrain of the study area is very different,and the main type of landform includes the river valley alluvial plain and erosion and denudation structures.The exposed strata in the study area are very complex and the lithology mainly includes sandstone,silty mudstone,argillaceous siltstone,mudstone,limestone and dolomite.In this study area the structures development and the fractures are distributed along the river of zemu.The average annual rainfall is 1165mm.?2?The types of groundwater can be divided into quaternary unconsolidated rock pore water,bedrock fissure water and carbonate rock karst water.The water-bearing rock groups are classified according to the corresponding types of groundwater.Precipitation is the main source of supply.Groundwater flows along the crevasse to low-lying place,which drains off the surface of the valley,and in the valleys deep cutting zone mainly in the form of the spring water.?3?According to the water sample data of 55 groups in the study area,the spatial distribution and correlation of groundwater chemical types and major components in the study area are studied.?1?Based on the statistical analysis of 55 groups of water samples in the study area,the chemical types of groundwater in the study area are mainly HCO₃-Ca.?2?Based on sufer software,the spatial interpolation of the main components is analyzed,and the distribution characteristics and variation rules of the main components can be obtained.?3?On the basis of SPSS software,the correlation between principal components and main components is analyzed.For example,TDS is significantly associated with Ca²⁺?Mg²⁺?HCO₃^-and SO₄^2-.?4?To evaluate groundwater quality according to the quality standards of groundwater and the sanitary standards for drinking water in rural areas.?1?Based on groundwater quality standards,the single factor evaluation results show that Fe,oxygen consumption,NO₃^-and NO₂^-and NH₄⁺ions components are overweight,those are the impact of groundwater water quality category.According to the evaluation results of the Nemerow index method,the water samples with good quality is 55%,and the water samples with poor water quality accounted for 45%in the study area.The Fuzzy comprehensive evaluation method of the evaluation results show that the groundwater quality in?class water standard water samples accounted for 76%,more than?class standard water accounted for 24%.Generally speaking,the groundwater quality in the study area is better,however,some individual evaluation indexes have exceeded the standard?Oxygen consumption?NO₃^-?NO₂^-?NH₄⁺?.?2?Based on the hygienic standard of drinking water in rural areas,the results of fuzzy comprehensive evaluation showe that the overall water quality is good and meet the safety standards of drinking water.The evaluation results are only JS029 and JS038 for the water samples of grade 3 water,and the water quality is considered unsafe.According to the evaluation results of water quality under different water quality standards,the detection rate,the over level rate and the stability of the evaluation factors,NO₃^-ion is the most important factor affecting groundwater quality in the study area.?5?According to the established hydrogeological conditions,the hydrogeological conceptual model is established.The boundary between the east and west of the study area is set to the boundary of the constant water head according to the groundwater flow line.The top of the aquifer is the unconfined aquifer,consisting of pore aquifers and fissure aquifers and karst aquifers.The second layer is the second floor of the weak permeable layer.The lower part is karst aquifer and clastic pore aquifer.?6?The distribution of TDS and NO₃^-ions in the next 20 years are calculated and analyzed.The pollution halo of TDS and NO₃^-ions along the direction of groundwater runoff has a tendency to expand downstream.The results of the analysis shows that the phenomenon of enrichment concentration of the TDS and NO₃^-ions factors have appeared near the fault zone.The maximum content of TDS and NO₃^-ions in the 20th year is 7316.44 mg/L,162.8640 mg/L,exceeding the quality standard of grade 3,and the safety of groundwater quality is threatened.According to the source and migration characteristics of pollutants,reasonable management and protection measures are put forward to provide scientific theoretical basis for rational exploitation of groundwater resources in zemu river basin.