Characterwastics Of Nitrogen And Its Influence On Aquatic Organwasms In Surface Water Of Linhuan,Huaibei

In recent years,in eastern China,the coal mining subsidence area in high water table with the expansion of the area of subsidence water,the surface water environment quality was seriously challenged by human and natural activities.Linhuan Mining Area was a mining area mainly developed by Huaibei City.As the main source of production and life for the residents around the mining area,it was extremely important for the ecological environment and the health of the residents.The study found that TN content in Linhuan Mining Subsidence Area was relatively high,and eutrophication occured in some subsidence areas.Nitrogen pollution not only brought problems such as environmental pollution and ecological balance damage,but also threatened human health.Nitrogen pollution in the study area was serious and the source of nitrogen was complex.Based on the full investigation of domestic and foreign research status and field investigation,this paper mainly took Linhuan Coal Mining Subsidence Area in Huaibei,Anhui Province as the research object,and collected surface water?river water and subsidence water area?a total of 20 samples,a total of 20 samples of plants and fish.Tested and analyzed the conventional water chemical indicators and nitrogen and oxygen isotope values of water samples,and nitrogen isotope values of plant and fish samples.In this study,the surface water of Huaibei Linhuan mining area was analyzed for hydrochemical characteristics and eutrophication.The source of nitrogen was traced by isotope technology in the mining area of river and subsidence area.The spatial variation characteristics of nitrogen isotopes of aquatic organisms?plants and fishes?were identified and analyzed by statistical analysis method,and the impact of ecological environment factors on them was discussed.The result showed:1?The TDS content of surface water of ranges from 557.60mg/L to 2137.85mg/L,with an average value of 960.07mg/L,which belongs to the type of highly mineralized water.Cations of surface water were mainly Na⁺,Mg²⁺,and anions of surface water were mainly SO₄^2-,HCO₃^-.The hydrochemical types of river water and subsidence area were:Na⁺-Mg²⁺-HCO₃^-and Na⁺-Cl^--SO₄^2-.Gibbs diagram showed that the ion composition of surface water in Linhuan Mining Area was affected by evaporation and rock weathering.2?The surface water comprehensive trophic state index?TLI?of Linhuan coal mining subsidence area was 62.34,which was at a moderate eutrophication level,and TN was the largest contribution index.The content of TN,NH₄⁺-N and NO₃^--N in the subsidence area were higher than those in river water.The concentration of nutrients in the study area was affected by temperature and rainfall.The content of nutrients in high flow season was lower than that in low flow season.3?The values of?¹⁵N and?¹⁸O in river water ranged from 9.2‰¹5.2‰ and-1‰².9‰,with the average value of 11.02‰and 1.07‰;The values of?¹⁵N and?¹⁸O in river water ranged from-2⁷.8‰and-8.9‰⁸.7‰,with the average value of-1.53‰and 4.15‰.The use of sewage and organic manure was the main source of nitrogen in the river water;The main source of nitrogen in the subsidence water area was soil organic nitrogen,nitrogen-containing fertilizer,domestic sewage and manure.At the same time,there was no obvious nitrification and denitrification reaction in river water and subsidence water area.4?The calculation results of the IsoSource model showed that the proportion of nitrogen sources in river water was in the order of manure and sewage?66.6%?>soil nitrogen?8.2%?>nitrogen-containing fertilizer?25.2%?.The proportion of nitrogen sources in the subsidence area is nitrogenous fertilizer?52.0%?>soil nitrogen?18.0%?>manure wastewater?30.0%?.The spatial difference of nitrogen source and contribution rate from river water to subsidence area was influenced by land use types around.5?The?¹⁵N range of river plant samples in Linhuan mining area was between 7.2‰8.7‰,and the?¹⁵N range of plant samples in coal mining subsidence area was between 3.9‰⁶.‰.The?¹⁵N range of river fish samples in Linhuan mining area was between 11.7‰to 16‰,and the?¹⁵N range of fish samples in subsidence area of Linhuan mining area was between 3.6‰to 9.8‰.Single factor analysis of variance showed that the?¹⁵N sampling point location on aquatic organisms had remarkable effect on the value of aquatic animals and plants of the?¹⁵N value was significantly affected by the nutrient level,foreign pollutants produced by human activity were contains the?¹⁵N isotope ratio was relatively high,thus affecting the?¹⁵N value of the aquatic life.Water resources in coal mining subsidence areas were very important for the sustainable development of the socio-economic and ecological environment in the mining area.Defining the source of surface water and nitrogen can provide a scientific basis for controlling nitrogen load in the coal mining subsidence area and improving the comprehensive management and efficient use of water resources.Applying the technology of nitrogen stable isotope to study the change law of the isotopes of aquatic organisms in the water ecosystem can not only reflect the geochemistry of aquatic organisms,but also provide basic scientific basis for ecosystem assessment and ecological environment restoration.