Use of cyanopigment determination as an indicator of cyanotoxins in drinking water

Abstract

The indicator function of the fluorescence signals of the cyanopigments phycocyanin and phycoerythrin as early warning parameters against the microcystins in drinking water was investigated by lab- and pilot-scale studies. The early warning function of the fluorescence signals was examined with regard to the signals' real-time character, their sensitivity and the behaviour of the cyanopigments in different treatment stages in comparison to microcystins. Fluorescence measurements confirmed the real-time character, since they can be carried out on-site without the pre-concentration of pigments. The limit of detection of phycoerythrin is determined at 0.7 microg/L and of phycocyanin at 5.3 microg/L respectively. If the pigment/microcystin ratio is known and calculated to be higher than 1, very low microcystin concentrations can be estimated by the fluorescence signals. The compared behaviour of both pigments and selected microcystins (MC-LR and MC-RR) during water treatment shows that pigments have an early warning function against microcystins in conventional treatment stages using pre-oxidation with permanganate, powdered-activated carbon and chlorination. In contrast, cyanopigments do not have an early warning function if chlorine dioxide is used as a pre-oxidant or final disinfection agent. In order to use pigment control measurements in drinking water treatment the initial pigment/toxin ratio of the raw water must be known.

Simultaneous removal of multiple odorants from source water suffering from septic and musty odors: Verification in a full-scale water treatment plant with ozonation

“…Organic particles including algal cells are trapped in flocs during coagulation, and then settle down in the bottom of settlers until the discharge of sludge. Algal cells trapped in sludge may rupture when the sludge residence time in the sedimentation tank was long enough (sludge was removed once a day from the sedimentation tank) or the sedimentation sludge removal was incomplete, releasing the intracellular odorants (Schmidt et al, 2002(Schmidt et al, , 2009Kommineni et al, 2009;Ho et al, 2012;Li et al, 2012aLi et al, , 2012bZamyadi et al, 2012Zamyadi et al, , 2013Zamyadi et al, , 2014Ho et al, 2013). On the other hand, anaerobic digestion could easily take place in sedimentation sludge because of the presence of algal cells and other organic materials.…”

Fate of geosmin and 2-methylisoborneol in full-scale water treatment plants

“…Furthermore, the mass balance between the ratio of supernatant and intracellular compounds post-PAC indicated the release of a fraction of cell-bound geosmin and MIB and their adsorption by PAC. Cell membrane damage due to hydraulic pressure during supernatant pumping could be responsible for the observed release of intracellular compounds (Schmidt et al, 2002(Schmidt et al, , 2009). …”

“…This is because, while the removal efficiency of conventional chemical-physical (coagulationflocculation, clarification and filtration) and disinfection treatment processes for the removal of extracellular geosmin and MIB is very low, at less than 20% (Jung et al, 2004;Persson et al, 2007;Newcombe et al, 2010;Srinivasan and Sorial, 2011), their removal within the intact cells as intracellular compounds is highly efficient. Cell damage during the treatment processes including hydraulic stress from pumps or pre-oxidation, and subsequent release of intracellular T&O compounds to cause further treatment issues, is therefore a major risk (Peterson et al, 1995;Schmidt et al, 2002Schmidt et al, , 2009). Finally, the release of T&O compounds from damaged cells could be an indicator of the release of other harmful metabolites from the cells, including cyanotoxins (Zamyadi et al, 2010).…”

“…Hence, the handling and treatment of spent filter backwash water and sludge has proved to be an operational challenge (Ho et al, 2012(Ho et al, , 2013. The sludge bed of sedimentation tanks, filter media and sludge handling basins have been the main sites of cell accumulation and could be sources of toxin release within WTPs (Schmidt et al, 2002;Kommineni et al, 2009;Schmidt et al, 2009;Ho et al, 2012;Zamyadi et al, 2012Zamyadi et al, , 2013bHo et al, 2013). While these studies have mainly focused on toxins produced by cyanobacterial cells, the fate of cyanobacterial T&O compounds within full-scale WTPs and the associated impact on the aesthetic quality of the treated water has not been studied extensively.…”

Fast Screening Techniques for Neurotoxigenic Substances and Other Toxicants and Pollutants Based on Thermal Lensing and Microfluidic Chips

“…Taking this into account, FIA-TLS already compares favorably with recently reported techniques, and could be used as early warning systems for microcystins, which are based on the fluorescence detection of cyanopigments. 76 In addition, FIA-TLS offers a manifold for the direct determination of microcystin based on an approach similar to the above-described for OP and carbamate pesticides. This is possible by a protein phosphatase inhibition assay, because microcystin is a known inhibitor of protein phosphatase 2A (PP2A).…”