Comparative assessment of the environmental pollution and marine economic growth of Guangxi and China by using the environmental Kuznets curve fitting model

This study examined the nexus between per capita gross ocean product (GOP) growth and total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) discharged from land-based sources in Guangxi and China. Multiple pollution indicators, such as red tide area (RTA), seawater quality area (SWQA), and eutrophication area (EA), were used as marine environmental quality indicators, and annual time series data during the period 2010-2019 were employed. The data were analyzed using the environment Kuznets curve fitting model. Results showed that the average annual growth rates of the GOP and gross domestic product (GDP) of China were 9.88% and 10.79%, respectively, and those of Guangxi were 13.62% and 10.02%, respectively. The average annual GOP ratio in GDP for Guangxi and China was 6.59 and 9.47, respectively. The marine tertiary industry was the most dominant marine industry; it accounted for 41.12-50.01% (mean: 46.12%) of Guangxi's GDP and 47-60% (mean: 52.47%) of China's GDP. The TP, COD, SWQA, and EA of Guangxi and the TP, TN, COD, SWQA, and EA of China displayed inverted U-shaped GOP growth. These findings indicate that the marine economic growth and marine environmental quality of Guangxi and China are harmonious. However, TN increased synchronously with marine economic growth in Guangxi. Therefore, the industrial structure must be further optimized, pollutant discharge management must be strengthened, and the harmonious development of Guangxi's marine economy and marine environment needs to be promoted.