Environmental threats induced heavy ecological burdens on the coastal zone of the Bohai Sea, China

Junbao Yu; Di Zhou; Miao Yu; Jisong Yang; Yunzhao Li; Bo Guan; Xuehong Wang; Chao Zhan; Zhikang Wang; Fanzhu Qu

doi:10.1016/j.scitotenv.2020.142694

Environmental threats induced heavy ecological burdens on the coastal zone of the Bohai Sea, China

Sci Total Environ. 2021 Apr 15:765:142694. doi: 10.1016/j.scitotenv.2020.142694. Epub 2020 Oct 5.

Authors

Junbao Yu¹, Di Zhou², Miao Yu², Jisong Yang³, Yunzhao Li², Bo Guan⁴, Xuehong Wang², Chao Zhan², Zhikang Wang², Fanzhu Qu⁵

Affiliations

¹ Key Laboratory of Ecological Restoration and Conservation of Coastal Wetlands in Universities of Shandong, The Institute for Advanced Study of Coastal Ecology, Ludong University, Yantai 264025, PR China. Electronic address: junbao.yu@gmail.com.
² Key Laboratory of Ecological Restoration and Conservation of Coastal Wetlands in Universities of Shandong, The Institute for Advanced Study of Coastal Ecology, Ludong University, Yantai 264025, PR China.
³ Key Laboratory of Ecological Restoration and Conservation of Coastal Wetlands in Universities of Shandong, The Institute for Advanced Study of Coastal Ecology, Ludong University, Yantai 264025, PR China. Electronic address: yjswill@126.com.
⁴ Key Laboratory of Coastal Environment Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China.
⁵ Shandong Provincial Key Laboratory of Eco-environmental Science for Yellow River Delta, Binzhou University, Binzhou 256601, PR China.

PMID: 33071117
DOI: 10.1016/j.scitotenv.2020.142694

Abstract

The environment of the Bohai Sea is under enormous pressure because of rapid economic and urban development associated with increased population inhabiting the coastal zone. Environmental threats to the coastal ecosystem were analyzed using 2006-2017 statistical/monitoring data from the State Oceanic Administration, China. The results showed that harmful algal blooms occurred a total of 104 times during the period of 2006-2017, for a cumulative area of more than 21,275 km². The main environmental threats came from offshore oil and gas production in the form of hydrocarbon pollution during extraction, as well as from urban wastewater and sewage. Oil pollution, mainly generated from spills, offshore oil platforms and large number of vessels/ports, was found to cause very severe negative impacts on the environment. Another threat is from excessive groundwater exploitation which has resulted in seawater intrusion and soil salinization occurrence in more than 90% of coastal areas around the Bohai Sea. The maximum distance of intrusion by seawater and soil salinization was more than 40 and 32 km inland, respectively. Contamination by terrestrial pollutants was identified as another threat affecting the environment quality of the Bohai Sea. Approximately 840,000 t of pollutants were carried into the sea by major rivers annually for 2010-2017. The standard discharge rate of terrestrial-source sewage outlets did not exceed 50%; however, only 13.12% of sea areas adjacent to sewage outlets (rivers) met the environmental quality requirements for functional marine areas. The results also showed the frequency of storm surges in the Bohai Sea which was 8.83 times per year and the resulting annual direct economic losses reached (RMB) 1.77 billion for 2006-2017. The results highlight the urgent need to implement an ecological management strategy to reduce the heavy ecological burdens in the coastal zone of the Bohai Sea.

Keywords: Bohai Sea; Coastal zone; Ecological disaster; Environmental threats; Terrestrial pollutants input.