Analytical insight into degradation processes of aminopolyphosphonates as potential factors that induce cyanobacterial blooms

Damian Drzyzga,Jacek Lipok

doi:10.1007/s11356-017-0068-1

Damian Drzyzga, Jacek Lipok

Open Access

https://doi.org/10.1007/s11356-017-0068-1

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Abstract

Aminopolyphosphonates (AAPs) are commonly used industrial complexones of metal ions, which upon the action of biotic and abiotic factors undergo a breakdown and release their substructures. Despite the low toxicity of AAPs towards vertebrates, products of their transformations, especially those that contain phosphorus and nitrogen, can affect algal communities. To verify whether such chemical entities are present in water ecosystems, much effort has been made in developing fast, inexpensive, and reliable methods for analyzing phosphonates. However, unfortunately, the methods described thus far require time-consuming sample pretreatment and offer relatively high values of the limit of detection (LOD). The aim of this study was to develop an analytical approach to study the environmental fate of AAPs. Four phosphonic acids, N,N-bis(phosphonomethyl)glycine (GBMP), aminotris(methylenephosphonic) acid (ATMP), hexamethylenediamine-N,N,N′,N′-tetrakis(methylphosphonic) acid (HDTMP), and diethylenetriamine penta(methylenephosphonic) acid (DTPMP) were selected and examined in a water matrix. In addition, the susceptibility of these compounds to biotransformations was tested in colonies of five freshwater cyanobacteria—microorganisms responsible for the so-called blooms in the water. Our efforts to track the AAP decomposition were based on derivatization of N-alkyl moieties with p-toluenesulfonyl chloride (tosylation) followed by chromatographic (HPLC-UV) separation of derivatives. This approach allowed us to determine seven products of the breakdown of popular phosphonate chelators, in nanomolar concentrations and in one step. It should be noted that the LOD of four of those products, aminemethylphosphonic acid (AMPA), N-phosphomethyl glycine (NPMG), N-(methyl)aminemethanephosphonic acid (MAMPA), and N-(methyl) glycine (SAR), was set below the concentration of 50 nM. Among those substances, N-(methylamino)methanephosphonic acid (MAMPA) was identified for the first time as the product of decomposition of the examined aminopolyphosphonates.

Highlights

Demand for organophosphonates has intensified in recent years because thousands of tons of these compounds are consumed by industry, agriculture, and households each year (Benbrook 2016, Coupe et al 2012, Studnik et al 2015)
Growing concerns about the quality of aquatic ecosystems should be associated with the implementation of methods that allow estimation of the environmental fate of aminophosphonate xenobiotics
Degradation of aminopolyphosphonic acids may be the result of two processes: the catalytic impact of metals ions (Nowack 2002, 2003) and metabolic activity of microorganisms (Drzyzga et al 2017)

Summary

Introduction

Demand for organophosphonates has intensified in recent years because thousands of tons of these compounds are consumed by industry, agriculture, and households each year (Benbrook 2016, Coupe et al 2012, Studnik et al 2015). The environmental consequence of this is the annual introduction of several thousand tons of aminopolyphosphonates (AAPs), which are released mainly into surface waters (Studnik et al 2015). Glyphosate (N-phosphonomethyl glycine) is applied in millions of kilograms per year worldwide, and its main metabolite AMPA (aminomethylphosphonic acid) appears as the most important contaminant and is accompanied by identification of toxic effects of glyphosate on some water organisms (Pesce et al 2009, Vendrell et al 2009). In 2015, glyphosate was classified as a Bprobable human carcinogen^ by the International Agency for Research on Cancer (IARC 2015)

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