Assessment of phosphorus release from alluvial sediments using single extraction: a case study in Can Gio, Southern Vietnam

Thi Thu Dung Tran^1*, Thanh Thoang Ngo¹, Ngoc Tuyen Nguyen¹, Bich Chau Tran¹, Minh Hoang Truong²

¹Faculty of Environment, University of Science, Vietnam National University, Ho Chi Minh city
²Faculty of Geology, University of Science, Vietnam National University, Ho Chi Minh city

Received 7 August 2020; accepted 30 October 2020

 

Abstract:
Sediment-water interaction is a complicated process; hence, it is essential to know the potential mobility of an element from sediment to the aquatic environment. In this study, the potential mobility of phosphorus (P) in sediment from Can Gio was investigated. Three single extractions were applied including a mild salt (NH₄Cl), an acid (HCl), and a base (NaOH) each representing different environmental factors during sediment resuspension. Other geochemical parameters were also determined. The total amount of P in the sediments varied from 320.41 mg/kg to 668.22 mg/kg in five sampling sites. The general range of potential mobility of P decreased as follows: P-mild (3.70-13.13 mg/kg) < P-base (36.80-78.53 mg/kg) < P-acid (133.85-380.57 mg/kg). Although P-acid was not easily released to the environment, its relatively high concentration can affect the aquatic environment when the environment becomes acidic.

Keywords: phosphorus release, sediment, sediment resuspension, single extraction.

Classification number: 5.1