Cyanobacteria and their secondary metabolites in three freshwater reservoirs in the United Kingdom (original) (raw)
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Water research, 2018
Freshwater cyanobacterial blooms are becoming increasingly problematic in regions that rely on surface waters for drinking water production. Microcystins (MCs) are toxic peptides produced by multiple cyanobacterial genera with a global occurrence. Cyanobacteria also produce a variety of other toxic and/or otherwise bioactive peptides (TBPs) that have gained less attention including cyanopeptolins (Cpts), anabaenopeptins (Apts), and microginins (Mgn). In this study, we compared temporal and spatial trends of four MCs (MCLR, MCRR, MCYR, MCLA), three Cpts (Cpt1020, Cpt1041, Cpt1007), two Apts (AptF, AptB), and Mgn690 in raw drinking water and at six surface water locations above these drinking water intakes in a eutrophic lake. All four MC congeners and five of six TBPs were detected in lake and raw drinking water. Across all samples, MCLR was the most frequently detected metabolite (100% of samples) followed by MCRR (97%) > Cpt1007 (74%) > MCYR (69%) > AptF (67%) > MCLA (6...
Journal of the Mexican Chemical Society, 2018
The occurrence of harmful algal blooms in nutrient-rich freshwater bodies has increased worldwide, including in the Pacific Northwest. Some cyanobacterial genera have the potential to produce secondary metabolites that are highly toxic to humans, livestock and wildlife. Reliable methods for the detection of cyanobacterial toxins with high specificity and low limits of detection are in high demand. Here we test a relatively new hybrid high resolution accurate mass quadrupole time-of-flight mass spectrometry platform (TripleTOF) for the analysis of cyanobacterial toxins in freshwater samples. We developed a new method that allows the quantitative analysis of four commonly observed microcystin congeners (LR, LA, YR, and RR) and anatoxin-a in a 6-min LC run without solid-phase enrichment. Limits of detection for the microcystin congeners (LR, LA, YR, and RR) and anatoxin-a were <5 ng/L (200-fold lower than the guideline value of 1 µg/L as maximum allowable concentration of MC-LR in drinking water). The method was applied for screening freshwaters in the Pacific Northwest during the bloom and post-bloom periods. The use of high resolution mass spectrometry and concomitant high sensitivity detection of specific fragment ions with high mass accuracy provides an integrated approach for the simultaneous identification and quantification of cyanobacterial toxins. The method is sensitive enough for detecting the toxins in single Microcystis colonies.
Environmental Monitoring and Assessment, 2010
Mansour Eddahbi (MED) (30°55′N, 6°53′W) and Almassira (ALM) (31°95′N, 6°72′W) are two Moroccan lake reservoirs located at an arid and semi-arid hydrographic basin, respectively. Both are used for irrigation, recreational activities and drinking-water production. This paper deals with the characterization and quantification of microcystins (MC) from two Microcystis aeruginosa blooms occurring in those reservoirs. The toxicity of the blooms was confirmed and evaluated by both mouse and Artemia bioassays. The calculated LD50 values revealed that the MED bloom had a medium toxicity (LD50 = 358 mg kg − 1 body weight), whereas the ALM bloom had low toxicity (LD50 = 829 mg kg − 1 body weight). The 24-h LC50 values were 1.88 and 4.15 mg ml − 1 for the MED and ALM blooms, respectively, using Artemia assay. The identification and quantification of MC variants were carried out by high performance liquid chromatography (HPLC) equipped with a photodiode array detector, and HPLC coupled to mass spectrometry. The MC content, as Microcystin-LR (MC-LR) equivalents, was higher in the MED bloom (64.4 μg g − 1 dry weight) than in the ALM bloom (9.9 μg g − 1 dry weight). Five MC variants were identified in the MED cyanobacteria bloom (MC-RR, MC-YR, MC-LR, MC-FR, and MC-WR) and only one (MC-LR) in the ALM bloom. The results show that the occurrence of toxic cyanobacteria blooms in the studied reservoirs may be regarded as a health hazard; therefore, cyanotoxin monitoring in them is highly recommended.
Toxins, 2021
Lake Karaoun is the largest artificial lake in Lebanon and serves multiple purposes. Recently, intensive cyanobacterial blooms have been reported in the lake, raising safety and aesthetic concerns related to the presence of cyanotoxins and cyanobacterial taste and odor (T&O) compounds, respectively. Here, we communicate for the first time results from a recent investigation by LC-MS/MS covering multiple cyanotoxins (microcystins (MCs), anatoxin-a, cylindrospermopsin, nodularin) in water and fish collected between 2019 and 2020. Eleven MCs were identified reaching concentrations of 211 and 199 μg/L for MC-LR and MC-YR, respectively. Cylindrospermopsin, anatoxin-a and nodularin were not detected. The determination of the total MCs was also carried out by ELISA and Protein Phosphatase Inhibition Assay yielding comparable results. Molecular detection of cyanobacteria (16S rRNA) and biosynthetic genes of toxins were carried out by qPCR. Untargeted screening analysis by GC-MS showed the p...
Toxins produced in cyanobacterial water blooms - toxicity and risks
Interdisciplinary Toxicology, 2009
Cyanobacterial blooms in freshwaters represent a major ecological and human health problem worldwide. This paper briefly summarizes information on major cyanobacterial toxins (hepatotoxins, neurotoxins etc.) with special attention to microcystins -cyclic heptapeptides with high acute and chronic toxicities. Besides discussion of human health risks, microcystin ecotoxicology and consequent ecological risks are also highlighted. Although significant research attention has been paid to microcystins, cyanobacteria produce a wide range of currently unknown toxins, which will require research attention. Further research should also address possible additive, synergistic or antagonistic effects among different classes of cyanobacterial metabolites, as well as interactions with other toxic stressors such as metals or persistent organic pollutants.
Journal of the Serbian Chemical Society, 2010
ABSTRACT In spite of substantial research on health and ecological risks associated with cyanobacterial toxins in past decades, our understanding to natural dynamics and variability of toxic cyanobacterial blooms is still limited. Here we report results of the long term monitoring 1998-1999 / 2001-2008 of three reservoirs (Vír, Brno, Nové Mlýny) where toxic blooms develop annually. These three reservoirs provide a unique model, because they are interconnected by a river Svratka, which allows possible transfer of phytoplankton as well as toxins from one reservoir to another. Frequency of occurrence and dominance of the major cyanobacterial taxa Microcystis aeruginosa did not change during the investigated period but substantial variability was observed in the composition of other phytoplankton. Although absolute concentrations of studied toxins (microcystins) differed among reservoirs, there were apparent parallel trends. For example, during certain years, microcystin concentrations were systematically elevated in all three studied reservoirs. Further, concentration profiles in three sites were also correlated (parallel trends) within individual seasons based on monthly samplings. Microcystin-LR, a variant for which World Health Organization recommended a guideline value, formed only about 30-50% of total microcystins. This is of importance especially in the Vír reservoir, which serves as a drinking water supply. Maxima in the cell-bound microcystins (intracellular; expressed per dry weight biomass) generally preceded the maxima of total microcystins (expressed per volume of water sample). Overall maximum concentration in biomass (all three reservoirs, period 1993-2005) was 6.1 mg/g dry weight; median values ranged 0.065 - 2.3 mg/g dry weight. These are generally high concentrations in comparison with both Czech Republic and worldwide reported data. Our data reveal substantial variability of both toxic cyanobacteria and their peptide toxins that should be reflected by detailed monitoring programs.