Effects of anthropogenic activities on long-term changes of nitrogen budget in a plain river network region: A case study in the Taihu Basin

• Published in: The Science of the total environment Vol. 645; pp. 1212 - 1220
• Main Authors: Huishu, Lian, Qiuliang, Lei, Xinyu, Zhang, Haw, Yen, Hongyuan, Wang, Limei, Zhai, Hongbin, Liu, Huang, Jr-Chuan, Tianzhi, Ren, Jiaogen, Zhou, Weiwen, Qiu
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.12.2018
• Subjects: Anthropogenic activities; basins; case studies; China; decision making; empirical models; Eutrophication; Export coefficient model; freshwater lakes; municipal wastewater; nitrogen; Nitrogen budget; Non-point source pollution; nonpoint source pollution; pollutants; pollution load; population density; population growth; rivers; Taihu Basin; urban areas; urbanization; China; Non-point source pollution; Taihu Basin; Anthropogenic activities; Nitrogen budget; Export coefficient model; Eutrophication
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.06.354

Over recent decades, Taihu Lake, the third largest freshwater lake in China, has borne the brunt of intensive human activities. Non-point source pollutants and discharges of domestic wastewater are now the main cause of eutrophication. To control non-point source pollution, it is useful to have a good understanding of the spatial and temporal distribution of N (nitrogen). In this study, we applied Export Coefficient Model (ECM) and the Net Anthropogenic Nitrogen Inputs (NANI) method to estimate the N loads in the Taihu Basin at county scale since 1980. We found that N inputs and exports had increased from 6432 and 3170 kg N km−2 yr−1 in 1980 to 9722 and 4582 kg N km−2 yr−1 in 2010, respectively. The 151% increase of N inputs, but 144% increase of riverine N outputs suggested the more N was retained within the Taihu Basin. Both the population density and the urban areas were strongly correlated with N inputs and exports. Approximately 38% of the N inputs were exported in 2010, but only 19% were exported in 1980. This ratio illustrated that human activities, especially urbanization and population growth, have upset N budget in the Taihu Basin. This study supported by empirical models provides a case to demonstrate the N cascade in the Taihu Basin and can also be used to support decision making and to facilitate the development of measures to control N in the future. [Display omitted] •Both inputs and exports of N increased substantially during the study period.•The NANI method and the ECM are first integrated to assess N load in a basin.•Urbanization, economic/population growth are key factors of spatial-temporal changes.•The contribution of agricultural source to N exports was decreased.•Destruction of the N balance of the ecosystem is investigated in the Taihu Basin, China.