[Shallow Groundwater Around Plateau Lakes: Spatiotemporal Distribution of Nitrogen and Its Driving Factors]

Gui-Fang Li; Heng Yang; Yuan-Hang Ye; Qing-Fei Chen; Rong-Yang Cui; An-Qiang Chen; Dan Zhang

doi:10.13227/j.hjkx.202109195

[Shallow Groundwater Around Plateau Lakes: Spatiotemporal Distribution of Nitrogen and Its Driving Factors]

Huan Jing Ke Xue. 2022 Jun 8;43(6):3027-3036. doi: 10.13227/j.hjkx.202109195.

[Article in Chinese]

Authors

Gui-Fang Li¹, Heng Yang¹, Yuan-Hang Ye¹, Qing-Fei Chen¹, Rong-Yang Cui², An-Qiang Chen³, Dan Zhang¹

Affiliations

¹ College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China.
² Key Laboratory of Mountain Surface Processes and Ecological Regulation, Chinese Academy of Sciences, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of Water Resources, Chengdu 610041, China.
³ Agricultural Environment Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650201, China.

PMID: 35686772
DOI: 10.13227/j.hjkx.202109195

Abstract

Shallow groundwater around plateau lakes is one of the important sources of production and potable water. Shallow groundwater NO₃^--N pollution driven by factors such as surface nitrogen input load, rainfall, and irrigation is serious and threatens the water quality of plateau lakes. In order to identify the characteristics of nitrogen pollution and its driving factors in shallow groundwater, 463 shallow groundwater samples were collected from wells in farmland and residential areas around eight plateau lakes of Yunnan in the rainy and dry seasons in 2020 and 2021. The results showed that the average values of ρ(TN), ρ(NO₃^--N), ρ(ON), and ρ(NH₄⁺-N) in shallow groundwater were 24.35, 15.15, 8.41, and 0.79 mg·L^-1, respectively. Nearly 32% of the shallow groundwater samples around the eight lakes failed to meet the groundwater Class Ⅲ water quality requirements (GB/T 14848) of 20 mg·L^-1 for NO₃^--N. Among them, the NO₃^--N concentration in the shallow groundwater around Erhai Lake, Qiluhu Lake, and Dianchi Lake had the highest rate of exceeding the standard, followed by that around Xingyunhu Lake, Yangzonghai Lake, Yilonghu Lake, Fuxianhu Lake, and Chenghai Lake as the smallest. Land use and seasonal changes affected the concentration and composition of various forms of nitrogen in shallow groundwater. The concentration of various forms of nitrogen in shallow groundwater in the farmland area was higher than that in the residential area. The nitrogen concentration in shallow groundwater in farmland was higher than that in residential areas. Except for NH₄⁺-N, the concentration of various forms of nitrogen in shallow groundwater in the rainy season was higher than that in the dry season. NO₃^--N was the main nitrogen form in shallow groundwater; the fraction of TN was 57%-68%, and the fraction of ON was 27%-38%. The EC, DO, ORP, and T in shallow groundwater were the key factors reflecting or affecting the concentration of various forms of nitrogen in shallow groundwater, whereas soil factors had a weak impact on the concentration of various forms of nitrogen in shallow groundwater.

Keywords: driving factor; nitrogen(N); plateau lake; shallow groundwater; spatiotemporal distribution.

MeSH terms

China
Environmental Monitoring / methods
Groundwater*
Lakes
Nitrates / analysis
Nitrogen / analysis
Water Pollutants, Chemical* / analysis
Water Quality

Substances

Nitrates
Water Pollutants, Chemical
Nitrogen