Do Water Matrix and Particulate Buffering Capacity Affect the Rate and Extent of P Release?

Jinbo Zhao,Qian Li,Yingjun Xu,Li Xu

doi:10.4236/jwarp.2018.101004

Abstract

The aim of this study was to investigate the release of inorganic and organic phosphorus species from particles in rivers and estuaries during resuspension events such as storm, wind and tidal induced turbulence. To achieve this aim, laboratory beaker experiments were designed with autoanalyzer 3 (AA3). The study first investigates phosphorus equilibration in ultra-pure water (UHP) water, biotic river water and abiotic river water under short term and long term conditions. Then, three typical organic and inorganic phosphorus compounds were selected (orthophosphate, phytic acid (PTA) and β-D-glucose-6-phosphate monosodium salt (G-6-P)) to simulate the effect of addition input to river and estuaries in the time period of 150 h. The results show that in a turbulent river, dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP) will reach equilibrium between the particulate matter and the water column within 24 h. Additional input of DIP or DOP to the river, has different effects to the river nutrients balance. The buffering capacity of the suspended particulate matter (SPM) plays an important role and behavior difference to the inorganic and various organic phosphorus compounds.

Highlights

We focused on suspended particulate matter (SPM) on the effects of “alive” or “dead”, “short term” or “long term” resuspension, response to the “labile” or “refractory” organic phosphorus and “ideal” or river or sea water matrices
Autoclaving will lyse any bacterial cells in the SPM but could increase the rate of hydrolysis of any organic phosphorus compounds naturally present
Since the initial sorption of phytic acid did not displace IP, it appears that the slower second phase of sorption involves a different process from the initial buffering. In these constantly stirred batch reactor experiments, the water matrix had a significant effect on the release of IP and OP during equilibration with SPM and on the buffering capacity of the SPM when the systems were spiked with orthophosphate

Summary

Introduction

SPM has a large exposed surface area compared with benthic sediment, with easier access to dissolved oxygen, organic matter, macronutrients and micronutrients, facilitating the attachment and growth of bacteria [3] [4]. The key factors are temperature [5] [6] [7] pH [8] [9], dissolved oxygen [10], redox conditions (Eh) [11] [12], microbes [13] [14], SPM size distribution [15] [16] and SPM texture [17], the organic matter content of the sediment and salinity [18]. The property of SPM to resist fast uptake or release P to the aqueous solution is called buffer capacity. If the SPM has buffer capacity to P compounds, it means that the SPM could control the P transfer and possess at a certain time, in addition to reduce/slow down negative effects of P contaminants on the water quality

Objectives

Results

Conclusion