Human activities aggravate nitrogen-deposition pollution to inland water over China

• 来源期刊: 国家科学评论（英文版）
• 关键词: N deposition N concentration dam water area human activity
• 年，卷（期）: 2020,（2）
• 页码范围: 430-440
• 页数: 11页
• 语种: 英文
• DOI: 10.1093/nsr/nwz073

摘要

In the past three decades,China has built more than 87 000 dams with a storage capacity of≈6560 km3 and the total surface area of inland water has increased by 6672 krn2.Leaching of N from fertilized soils to rivers is the main source of N pollution in China,but the exposure of a growing inland water area to direct atmospheric N deposition and N leaching caused by N deposition on the terrestrial ecosystem,together with increased N deposition and decreased N flow,also tends to raise N concentrations in most inland waters.The contribution of this previously ignored source of N deposition to freshwaters is estimated in this study,as well as mitigation strategies.The results show that the annual amounts of N depositions ranged from 4.9 to 16.6 kg.ha-1 · yr-1 in the 1990s to exceeding 20 kg.ha-1 · yr-1 in the 2010s over most of regions in China,so the total mass of AN (the net contribution of N deposition to the increase in N concentration) for lakes,rivers and reservoirs change from 122.26 Gg N · yr-1 in the 1990s to 237.75 Gg N · yr-1 in the 2010s.It is suggested that reducing the N deposition from various sources,shortening the water-retention time in dams and decreasing the degree of regulation for rivers are three main measures for preventing a continuous increase in the N-deposition pollution to inland water in China.