Response of phosphorus fractionation in lake sediments to anthropogenic activities in China

Zhaokui Ni; Shengrui Wang; Yue Wu; Jia Pu

doi:10.1016/j.scitotenv.2019.134242

Response of phosphorus fractionation in lake sediments to anthropogenic activities in China

Sci Total Environ. 2020 Jan 10:699:134242. doi: 10.1016/j.scitotenv.2019.134242. Epub 2019 Sep 2.

Authors

Zhaokui Ni¹, Shengrui Wang², Yue Wu¹, Jia Pu³

Affiliations

¹ Engineering Research Center of Ministry of Education on Groundwater Pollution Control and Remediation, College of Water Sciences, Beijing Normal University, Beijing 100875, China; Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
² Engineering Research Center of Ministry of Education on Groundwater Pollution Control and Remediation, College of Water Sciences, Beijing Normal University, Beijing 100875, China; China Three Gorges University, College of Hydraulic & Environmental Engineering, Yichang 443002, China; Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake- Watershed, Kunming, Yunnan Province 650034, China. Electronic address: wangsr@bnu.edu.cn.
³ Engineering Research Center of Ministry of Education on Groundwater Pollution Control and Remediation, College of Water Sciences, Beijing Normal University, Beijing 100875, China.

PMID: 31689671
DOI: 10.1016/j.scitotenv.2019.134242

Abstract

In this study, geochemical fractionation is used to establish the relationship between sediment phosphorus (P) pools and anthropogenic activities based on the dated sediment from a suite of lakes in China. Our extraction results showed that the inorganic P fractions, including Ca-P (46% of TP) and Fe/Al-P (24%), constitute most of the P in sediments. Soil erosion dynamics and geographic location are the dominant factors controlling the historical distribution and partitioning of Ca-P in sediments, while over the last few decades, industrial and domestic effluents were the leading factor controlling Fe/Al-P. The organic P (P_o) fractions, NaHCO₃-P_o, HCl-P_o, and Ful-P_o accounted for only 11%, 16% and 12% of P_o on average, respectively, whereas Hum-P_o and Res-P_o made up the dominant P_o fraction (59%) and were the main factors controlling P_o dynamics due to fertilizer and livestock breeding. Thus, the historical fraction of P in the sediment core can be used as an indicator of anthropogenic activities. Ca-P decreased in the top layers of the cores because of the implementation of the Soil and Water Conservation Law in China since 1991. However, Fe/Al-P and P_o continuously increased in the lakes from the economic backward area over the last few decades, which is largely due to enhanced point sources of pollution and an increase in the intensity of agricultural practices. As a potential P source, the massive accumulation of Fe/Al-P and P_o would be released into the overlying water to further facilitate eutrophication via increasing pH and alkaline phosphatase and decreasing in the dissolved oxygen concentration. Therefore, in order to control eutrophication more effectively and efficiently, it is essential that the accumulation of sediment Fe/Al-P and P_o be decreased immediately and domestic wastewater, poultry excreta, and fertilizer loss must be more carefully controlled, especially in economically backward areas.

Keywords: Anthropogenic tracers; Eutrophication risk; Phosphorus; Sediment core.