The 19th POPsNET Symposium, organized by the College of Earth and Environmental Sciences, Lanzhou University, and Key Laboratory for Environmental Pollution Prediction and Control, Gansu province, was held in Hezuo city of Gannan Tibetan Autonomous Prefecture of Gansu Province from August 15 to 18, 2020. Located at the junction of Gansu, Qinghai and Sichuan provinces, Hezuo city is the capital city and political, economic, cultural, scientific, technological and financial center of Gannan Tibetan Autonomous Prefecture. "The Yellow River originates in Qinghai and becomes a river in Maqu, Gannan". Gannan prefecture is one of the main catchment areas of the Yellow River runoff and an important ecological functional area with water conservation, soil and water conservation, carbon sink and carbon storage, windbreak and sand fixation, biodiversity protection and other functions. In the past 20 years, the problem of ecological damage in Gannan prefecture has been prominent due to overgrazing and illegal exploitation of mineral resources. In September 2019, General Secretary Xi Jinping put forward the ecological protection and high-quality development of the Yellow River Basin, and comprehensively implement the national strategy of ecological protection and high-quality development in the Yellow River Basin. It has become the primary task of Gannan ecological environment security to promote ecological restoration and environmental governance and to build a strong ecological security barrier in the upper reaches of the Yellow River. The meeting will help experts to understand the sensitive ecological and environmental problems and governance in the upper reaches of the Yellow River, and provide suggestions for the protection of the ecological environment in the upper reaches of the Yellow River.

Welcome speech to the symposium from academician Tao Shu of Peking University

Researcher Luo Yongming from Nanjing Institute of Soil Science, Chinese Academy of Sciences presided over the opening of the meeting

Tao Shu, academician of Peking University, Jiang Guibin, academician of Research Center for Eco-Environmental Sciences, Chinese Academy of Science, academician Zhao Jincai of Institute of Chemistry, Chinese Academy of Science, academician Zhu Lizhong of Zhejiang University, Academician Wu Fengchang of Chinese Research Academy of Environmental Sciences, as well as more than 30 winners of The National Science Fund for Distinguished Young Scholars, Chang Jiang Scholars, chief scientists of 863 and 973 programs from universities and research institutes all over the country were invited to attend the meeting. Professor Ma Jianmin, Professor Gao Hong, Associate Professor Huang Tao, and some teachers and graduate students of the College of Earth and Environmental Sciences attended the meeting.

Researcher Wang Zijian from the Research Center for Eco-Environmental Sciences， Chinese Academy of Sciences had a lively discussion with participating experts

Lively discussion at the meeting

Luo Yongming, director of Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science，Chinese Academy of Sciences, chief scientist of 973 programs, presided over the opening ceremony of the symposium, and Tao Shu, an academician of the Chinese Academy of Sciences and professor of Peking University, delivered a welcome speech. Focusing on the theme of "international frontier scientific issues and technical methods for the research and control of persistent organic pollutants under the new situation and requirements of ecological environment restoration and environmental governance", Professor Zhu Dongqiang of Peking University, researcher Li Fangbai, director of Guangdong Institute of Eco-Environmental Science and technology, and Zhou Dongmei, researcher of Institute of Soil Science，Chinese Academy of Sciences presented academic reports to the conference, They introduced and exchanged the research progress and frontier of black carbon in environmental geochemistry, multi-interface and multi-element coupling mechanism of heavy metal pollution prevention and control in soil rice system, opportunities and challenges of soil chemical remediation in organic contaminated sites. Experts and scholars at the meeting held a warm and in-depth discussion based on the theme report. The meeting deepened the understanding, friendship and cooperation of scientific research institutes in colleges and universities.

Academician Zhu Lizhong from Zhejiang University commented on the report