The effects of socioeconomic activities on water quality in Hainan Island, south China

Abstract

Water quality is intimately related to the livelihood of the numerous people, and affects the development and operating benefits of various industries in society. This study clarifies the effects of human-driven economic activities on inland water quality in Hainan Island, and reveals relationships between water quality and tourism on the island. Based on previously monitored data, this study uses a static Bayesian network and radial basis function neural network (RBFNN) to model and predict the future water quality. From 2012 to 2015, water quality in the Nandu, Wanquan and Changhua Rivers was good (at level II, GB3838-2002). The static Bayesian network demonstrated that Gross Output Value (GOV) of agriculture, GOV of fishery, GOV of animal husbandy and chemical oxygen demand (COD) discharge will significantly affect water quality in the Nandu and Changhua Rivers. The effect of tourism on water quality in Wanquan River was significantly higher than that on the Nandu and Changhua Rivers. In the Wanquan River, the DO content fluctuated greatly in comparison to the other two rivers, and unexpectedly, increased tourism led to higher DO values. However, it remains necessary to closely monitor negative changes in water quality due to tourism, especially in Wanquan River and eastern Hainan province. The developed RBFNN showed that the changes in water quality were predicted accurately in comparison with experimental values in the present study and the water quality also is continuously improving. Overall, results suggest that current anthropogenic socioeconomic activities had a modest effect on water quality in Hainan Island. Agriculture, fishery, animal husbandy and COD discharge were relatively important factors affecting water quality, while tourism had a perceptible effect in eastern Hainan. Our findings provide a reference for the balance of water quality, people’s livelihood and economic development (tourism and port construction) in Hainan province.

Water Quality Evaluation, Spatial Distribution Characteristics, and Source Analysis of Pollutants in Wanquan River, China

“…Comparing the average values of the indicators of the Wanquan River water quality with the Class III water quality standard in the Environmental Quality Standard for Surface Water (GB3838-2002) [28], we found that the overall water quality of the Wanquan River basin is good, with the average values of all indicators meeting the Class III water quality standard. Compared with Ma's research on the water quality of Wanquan River in 2012-2015, the water quality of Wanquan River decreased from Class II to Class III in 2021, which may be closely related to the development of tourism in this area [31]. In terms of the exceedance rate, Hg was the most serious element, reaching 54%, followed by TN and TP (both 17%) and NH 4 + -N and COD Mn (both 13%).…”