Transformation Products of Hazardous Cyanobacterial Metabolites in Water

Cyanotoxin release from the benthic, mat-forming cyanobacterium Microseira (Lyngbya) wollei in the St. Lawrence River, Canada

“…From this simple experiment, the half-life value of LWTX-1 was estimated at roughly 17 days at room temperature. Hiskia et al (2014) reported that some transformation pathways may contribute to water detoxification from cyanotoxins: temperature and pH-dependent decomposition, biological degradation, photolysis and photosensitized degradation.…”

“…Subsequently, the LWTX-1 toxin release rate and decay from a cyanobacterial mat kept under stable laboratory conditions were evaluated in order to estimate its persistence in the environment. The fate of some cyanobacterial metabolites released in water was reported (microcystins, nodularin, cylindrospermopsin) (Hiskia et al 2014) but there is still a lack of data regarding the fate of LWTX-1. Detection and quantification of LWTX-1 released by cyanobacterial mats in the overlying water required the development of an extraction and purification method to reduce the matrix effect while concentrating the toxin to offset its dilution by river waters.…”

Photocatalytic degradation of cyanotoxins and water taste and odor compounds using TiO2 based nanocatalysts and polyoxometalates

“…In accordance with the results given in this study on degradation and mineralization (TOC measurements and identification of formed intermediates) of GSM and MIB, it has been concluded that the same photodegradation mechanism is followed when POM and The degradation pathway followed for the degradation of MC-LR was studied by several [270] in the UV light and yet by only few studied so far in the visible range of the solar light [301,302]. As far as concerning the CYN, GSM and MIB their degradation pathway is studied only under UV light irradiation [2].…”

“…Although the functions of some of these secondary metabolites are still unknown, cyanobacteria have undergone to develop strategies beneficial for their survival and/or dominance in an environment. Some of these secondary metabolites include taste and odor compounds, terpenoids, anti-microbials, metal chelators, lactones, protease inhibitors, indole alkaloids, and most importantly potent toxins frequently called cyanobacterial toxins or cyanotoxins known to affect a wide range of living organisms [2].…”

“…So far, a number of studies have examined degradation pathways of MC-LR when conventional oxidants or AOPs are applied, including ozonation [25,26], chlorination [27], ultra-sonication [28], photolysis [29], TiO 2 /UV-A [18,19,30,31] and N-TiO 2 /UV-A [18]. The fact that analytical standards for MC-LR reaction intermediates are not commercially available complicates the identification of primary intermediates [2,154]. In this chapter, identification of intermediate products formed during the photocatalytic degradation of MC-LR using GO-TiO 2 under solar light and Degussa P25 under UV-A was carried out using LC-MS/MS.…”