ABSTRACT
To examine the effects of seasonal changes and precipitation on the concentrations of various nitrogen and phosphorus forms in Dianchi Lake, the concentrations of various nitrogen and phosphorus forms of atmospheric deposition were determined by UV spectrophotometry. Additionally, the contributions of nitrogen and phosphorus to water pollution in Dianchi Lake were discussed. The results showed that the atmospheric depositional nitrogen concentration in Dianchi Lake is generally consistent with the characteristics of the low rainy season and high dry season. The nitrogen and phosphorus load of atmospheric deposition was positively correlated with rainfall. Seasonal changes were mainly characterized by low dry season and high rainy season. The atmospheric depositional nitrogen load was dominated by dissolved inorganic nitrogen, which accounted for 63.70% of the total nitrogen deposition load. The phosphorus load was mainly PP, which accounted for 45.54% of the total phosphorus precipitation load. Excessive fertilization and loss of nitrogen and phosphorus from fertilizers are the major sources of nitrogen and phosphorus in atmospheric wet deposition. Combined with data from rivers entering the lake, the settlements of TN and TP in the atmospheric deposition of Dianchi Lake were 6.14% and 12.76% of the river load, respectively. Therefore, the primary source of pollution in Dianchi Lake was still the load brought by the river into the lake. However, the nitrogen and phosphorus fluxes in the atmospheric deposition of Dianchi Lake were at intermediate levels compared with other regions, so this contribution requires further investigation.
ABSTRACT
In order to survey the present pollution from volatile organic compounds in Baiyangdian Lake, 15 water samples were collected in March 2016, and analyzed for 54 VOCs by purge and trap gas chromatography-mass spectrometry. The distribution characteristics and health risk assessments were investigated, and the pollution from the VOCs was evaluated by a comprehensive pollution index. The survey showed that:â a total of 14 VOCs were detected in Baiyangdian water, with a 100% detection rate for dichloromethane, benzene, toluene, ethylbenzene, xylene, and 1,3,5-trimethylbenzene; xylene had the highest concentration with an average concentration of 564.9 ng ·L-1; and trichloroethylene had the lowest concentration with an average concentration of 3.3 ng ·L-1 and a detection rate of only 13.3%; â¡ the total concentration of VOCs in Baiyangdian water was between 423.0 and 4207.8 ng ·L-1, and benzene was the main pollutant, with its main source coming from the effluent from the upstream sewage treatment plant, the industrial wastewater, and the exhaust emissions of motor vehicles in the city; and â¢the health risk assessment showed that VOCs in Baiyangdian Lake did not produce carcinogenic and non-carcinogenic risks to humans, and the VOC comprehensive pollution index shows that the VOCs in the Baiyangdian Lake were at a clean level.
