Distribution and Pollution Assessment of Nutrients in the Surface Sediments of Lake in Huoqiu County

Abstract

To clarify the spatial distribution and pollution characteristics of nutrients in the surface sediments of Chengxi Lake and Chengdong Lake in Huoqiu County, total nitrogen (TN), total phosphorus (TP), and organic matter (OM) in 30 surface sediment samples of Chengxi Lake and Chengdong Lake were determined, and their pollution levels and sources were analyzed. The results showed that the contents of total nitrogen (TN), total phosphorus (TP), and organic matter (OM) in Chengxi Lake were significantly higher than those in Chengdong Lake, and their average contents were 746.23 mg·kg-1, 538.38 mg·kg-1, and 1.17% and 470.80 mg·kg-1, 492.08 mg·kg-1, and 0.68%, respectively. The spatial distribution in the north and northwest of Chengxi Lake was significantly higher than that in other areas and decreased from north to south. The C/N value indicated that the organic matter in Chengxi Lake and Chengdong Lake mainly came from unbundled plants and phytoplankton. Correlation analysis showed that total nitrogen (TN), total phosphorus (TP), and organic matter (OM) in Chengxi Lake and Chengdong Lake were homologous. The average values of TN and TP single index (STN and STP) of sediments in Chengxi Lake and Chengdong Lake were 0.67 and 1.18 and 0.42 and 1.08, respectively, indicating that TN in the two lakes was clean whereas TP was moderately polluted, and the average comprehensive pollution index (FF) was 1.51 and 1.31, respectively. The evaluation of organic index and organic nitrogen index showed that both Chengxi Lake and Chengdong Lake were clean.