Dynamics of TP Load in the Largest Freshwater Lake of China in the Past Decade

Abstract

In order to reveal the evolution of TP pollution in Poyang Lake and the driving mechanism, this paper analyses the TP concentration in Poyang Lake during the period of 2012-2022 based on Mann-Kendall test and Pearson coefficient method combined with exogenous influencing factors. Results revealed that (1) Trends of interracial TP concentration in Poyang Lake varied significantly, with peaks of 0.115, 0.293 to 0.05 mg/L in 2014 and troughs of 0.032, 0.003 to 0.002 mg/L in 2019 at each lake area. However, TP in The South Lake was the opposite. The spatial distribution pattern of TP concentration in Poyang Lake showed that The Middle Lake (0.083 mg/L) > North Lake (0.069 mg/L) > South Lake (0.053 mg/L), and there were correlations among the Middle Lake, North Lake to South Lake. TP concentration in Middle Lake was significantly and positively correlated with the TP concentration of Gan Jiang (r1=0.322), and TP concentration in Middle Lake and North Lake was also significantly correlated with the TP concentration of Rao River (r2=0.446, r3=0.537). Whereas, TP concentration in North Lake and South Lake were less affected by the rivers. This study thoroughly analyzed the changes in TP concentration in Poyang Lake during the last decade to view its space-time distribution pattern and the driving mechanism of multiple factors. Research results would facilitate to better understating the variation of TP concentration and supply the scientific bases for water resources management and protection in Poyang Lake.