Nitrogen And Phosphorus Loading From Different Sources In Dianchi Lake And Its Contributions Of Different Components

Eutrophication of Dianchi lake, through the study of the different sources of nitrogen and phosphorus load and its contribution to water pollution, in order to further implement the endogenous and exogenous pollution control in Dianchi and provide the basis for small watershed pollution control.The change in TN(total nitrogen) concentration of the rivers running into Dianchi Lake ranged between 2.91~94.01mg/L, with DIN(dissolved inorganic nitrogen)concentration contributing the most, in contrast to a relatively low percentage of the concentration of DON(dissolved organic nitrogen) and PN(particulatenitrogen); The total volume of TN loading from the rivers into Dianchi Lake reached 6908.47 t/a, with DIN loading contributing the most, averaging 67.15%; the contributions of DON and PN loading was similar, averaging 17.86% and 14.99% respectively; There was a significant difference in seasonal loading contributions of different nitrogen fractions, DIN peaked between March and September, its contribution averaging 74.01%; DON peaked between September and January, its contribution averaging 33.42%; In contrast, there was litter difference in monthly PN loading, peaking in February, contributing 40.19%.The TP concentration of lake inlet river of Dianchi lake is between 0.11~1.93mg/L, which the PP(particulate phosphorus) forms and DIP(dissolved inorganic phosphorus) forms is the main and the DOP(dissolved organic phosphorus) is lower; The TP loading of the rivers in Dianchi was 280.51 t/a, and most rivers are DIP forms into the lake with an average contribution of 43.48%; PP forms into the lake loading followed with the average contribution of 31.64%; DOP forms into the lake loading is low with the average contribution of 24.88%; DIP loading into the lake is higher contribution value appeared in dry season(March, April and November), which the average contribution rate reached 55.30%; PP into the lake loading contribution of higher values occurred in January and July, with the average contribution of 56.14%; The change of DOP loading into the lake was smaller, that the highest value appeared in December and its contribution was 21.85%.Dianchi Lake atmospheric wet deposition into the lake the concentration of TN average value ranged between 0.66~2.05 mg/L and the maximum value appeared in September, TN and different forms of nitrogen minimum values appeared in May. The concentration of DTN the average value ranged between 0.62~1.50 mg/L; The concentration of DIN the average value ranged between 0.58~1.31 mg/L. the concentration of PN in the average value is between 0.04~0.36 mg/L; The concentration of DON change is more intense, the highest in September(0.64mg/L).Dianchi Lake atmospheric wet deposition into the lake the concentration of TP average ranged between 0.04~0.21 mg/L, with the highest value appeared in October and the lowest value appeared in September. The concentration of DTP the average value ranged between 0.02~0.19 mg/L; The concentration of DIP the average value ranged between 0.01~0.08 mg/L; the concentration of PP the average value ranged between 0.01~0.10 mg/L; the concentration of DOP changes significantly, with October(0.64 mg/L) was the highest and the other month was lower. TP wet deposition load is 36.10 t, wherein, DTP load of 19.66 t, PP load of 16.44 t, DIP load of 15.21 t. Dianchi Lake TN sedimentation load for the whole year is 422.96 t, wherein, DTN load of 343.79 t, PN load 79.17 t, DIN load of 269.41 t. The wet deposition of different forms of nitrogen in Dianchi Lake is mainly contributed by the load of DIN into the lake, accounted for 63.7% of the load of TN into the lake; the load of DON into the lake was 17.59%, and the load of PN into the lake was 18.72%.The wet deposition of different forms of phosphorus in Dianchi Lake was dominated by PP and DIP into the lake load, which accounted for 45.54% and 42.14% of TP into the lake load, and the contribution of DOP into the lake was low, accounting for 12.32% of TP.Dianchi Lake Sediment Cores 36 points six levels of TN load, TP load, burial load and potentially release load changes potentially significant difference. Dianchi sediments of TN load at 0~20 cm ranged between18.30~277.67 g/m2,with TN load to Caohai highest; Nitrogen load of potentially release ranged between 6.67~84.03 g/m2, with the west of waihai is the highest; Nitrogen burial load variation ranged between 10.11~242.72 g/m2, with caohai is the highest.Dianchi sediments of TP load at 0~20 cm ranged between11.80~125.68 g/m2,with TP load to the southwest of waihai highest; Phosphorus load of potentially release ranged between 1.19~15.79 g/m2, with the caohai and the central waihai of higher; Phosphorus burial load variation ranged between 7.62~118.18 g/m2, with southwest of waihai is the highest. Dianchi Lake sediments the amount of TN load is 29755.86 t at 0~20cm; The amount of nitrogen load of potential release is 8943.61 t, accounting for the total load of TN contribution for 30.06%; The amount of nitrogen burial load is 20812.25 t, which accounted for 69.94% of the total load of TN; The amount of TP load was 14244.74 t. The amount of phosphorus load of potential release is 2621.73 t, which accounted for 18.40% of the total load of TP; The amount of phosphorus burial load is 11623.01 t, which accounted for 81.60% of the total load of TP.