Long-term variations of water quality and nutrient load inputs in a large shallow lake of Yellow River Basin: Implications for lake water quality improvements

Shengyue Yu; Xinzhong Du; Qiuliang Lei; Xue Wang; Shengcai Wu; Hongbin Liu

doi:10.1016/j.scitotenv.2023.165776

Long-term variations of water quality and nutrient load inputs in a large shallow lake of Yellow River Basin: Implications for lake water quality improvements

Sci Total Environ. 2023 Nov 20:900:165776. doi: 10.1016/j.scitotenv.2023.165776. Epub 2023 Jul 25.

Authors

Shengyue Yu¹, Xinzhong Du², Qiuliang Lei¹, Xue Wang³, Shengcai Wu⁴, Hongbin Liu⁵

Affiliations

¹ State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Key Laboratory of Non-point Source Pollution Control, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
² State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Key Laboratory of Non-point Source Pollution Control, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: duxinzhong@caas.cn.
³ Water Conservancy Science and Technology Test Center of Hetao Irrigation District, Inner Mongolia 015000, China.
⁴ Agriculture and Animal Husbandry Technology Promotion Center, Bayannur, Inner Mongolia 015100, China.
⁵ State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Key Laboratory of Non-point Source Pollution Control, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: liuhongbin@caas.cn.

PMID: 37499820
DOI: 10.1016/j.scitotenv.2023.165776

Abstract

Many studies have investigated water quality changes in freshwater lakes, however, studies examining long-term relationships between lake water quality and total nitrogen (TN) and total phosphorus (TP) load inputs and investigating the causes that indicate improvements in water quality are limited. In this study, we utilized the LOADEST model to estimate TN and TP load inputs, assessed lake trophic status using the integrated nutrient index method, and explored trends and relationships between nutrient load inputs and water quality in Wuliangsuhai Lake, a large shallow lake of Yellow River Basin in China. Additionally, we identified the causes for recent water quality improvements and proposed future management strategies to further improve the water quality. Our findings revealed that water quality in Wuliangsuhai Lake of Yellow River basin has been improved mainly due to the abatements of nutrient load inputs from the watershed. Between 2010 and 2020, TN and TP loads from the watershed decreased significantly by 65.12 % and 89.4 %, respectively. TN and TP concentrations also notably decreased across the lake areas, including the inlet (91.21 % and 95.59 %), central (73.49 % and 87.12 %), and outlet (40.68 % and 40.54 %) areas. Correlation analysis confirms a strong positive relationship between lake water quality and nutrient load inputs (excluding the outlet area), highlighting the impact of nutrient inputs on lake water quality. The results indicated that the recent water quality improvements in the lake was mainly because of effective control for point source pollution from industrial wastewater and domestic sewage and the non-point source pollution control holds the potential to further improve the water quality.

Keywords: Nutrient load inputs; Trend analysis; Water quality; Wuliangsuhai Lake.