Characters of Annual Variation and Seasonal Variation of Main Chemical Elements in Water Quality of Jiulong River Estuary

Abstract

The research results showed that the water quality of Jiulong River Estuary has been improved in the past 10 years, especially the permanganate index, ammonia nitrogen, total phosphorus and petroleum showed a continuous decline from 2016 to 2020, indicating that the water quality of Jiulong River Basin has been significantly improved during the Thirteenth Five-Year Plan period, however, the total nitrogen exceeded the standard seriously, based on the survey data of surface water of Jiulong River estuary for 10 years from 2011 to 2020. The characteristics of seasonal variation are as follows: In 2020, permanganate index, ammonia nitrogen, total nitrogen, inorganic nitrogen and total phosphorus are relatively low in summer and high in winter; and the chemical oxygen demand is relatively low in winter and high in autumn; and the petroleum is relatively low in autumn and high in spring and winter.Based on the comparative analysis of the water quality of monitoring sections of Jiulong River and other major rivers entering the sea in Fujian Province, such as Minjiang River, Jinjiang River, Longjiang River and Mulan River from 2011 to 2020, the water quality of Minjiang River estuary and Jinjiang River estuary is relatively good, and Longjiang River estuary and Mulan River estuary are relatively poor, and Jiulong River estuary is average. It will provides reference for environmental planning and management of Jiulong River.

Keywords

• estuary
• water quality assessment
• ammonia nitrogen
• total nitrogen
• total phosphorus
• jiulong river