Occurrence Of Cyanotoxins Research Articles

First Report of Microcystins and Anatoxin-a Co-occurrence in San Roque Reservoir (Córdoba, Argentina)

Fil: Ruiz, Marcia. Secretaria de Ambiente y Desarr.sustentable de la Nacion. Instituto Nacional del Agua y del Ambiente(cordoba); Argentina

PH effects on the adsorption of saxitoxin by powdered activated carbon

Increasing occurrence of cyanotoxins in surface waters worldwide pose significant problems, including those for drinking water utilities. In this study, the removal of saxitoxin (STX) from three different powdered activated carbons (PACs) was studied. STX is one of the most toxic paralytic shellfish toxins (PSTs), albeit not the most prevalent. The results showed that a wide range of non-electrostatic and electrostatic interactions appeared to play a role in the sorption of STX on PAC, depending on the solution pH, NOM concentration, and other factors. A bituminous coal-based PAC, that was studied in greatest detail, showed a trend of increasing sorption capacity for STX with increasing pH. NOM appeared to significantly inhibit adsorption when the pH was nearly neutral (e.g. 7.05), yet it had less effect at higher pH levels of 8.2 and 10.7.

Cyanobacteria and Cyanotoxins: The Influence of Nitrogen versus Phosphorus

The importance of nitrogen (N) versus phosphorus (P) in explaining total cyanobacterial biovolume, the biovolume of specific cyanobacterial taxa, and the incidence of cyanotoxins was determined for 102 north German lakes, using methods to separate the effects of joint variation in N and P concentration from those of differential variation in N versus P. While the positive relationship between total cyanobacteria biovolume and P concentration disappeared at high P concentrations, cyanobacteria biovolume increased continually with N concentration, indicating potential N limitation in highly P enriched lakes. The biovolumes of all cyanobacterial taxa were higher in lakes with above average joint NP concentrations, although the relative biovolumes of some Nostocales were higher in less enriched lakes. Taxa were found to have diverse responses to differential N versus P concentration, and the differences between taxa were not consistent with the hypothesis that potentially N2-fixing Nostocales taxa would be favoured in low N relative to P conditions. In particular Aphanizomenon gracile and the subtropical invasive species Cylindrospermopsis raciborskii often reached their highest biovolumes in lakes with high nitrogen relative to phosphorus concentration. Concentrations of all cyanotoxin groups increased with increasing TP and TN, congruent with the biovolumes of their likely producers. Microcystin concentration was strongly correlated with the biovolume of Planktothrix agardhii but concentrations of anatoxin, cylindrospermopsin and paralytic shellfish poison were not strongly related to any individual taxa. Cyanobacteria should not be treated as a single group when considering the potential effects of changes in nutrient loading on phytoplankton community structure and neither should the N2-fixing Nostocales. This is of particular importance when considering the occurrence of cyanotoxins, as the two most abundant potentially toxin producing Nostocales in our study were found in lakes with high N relative to P enrichment.

Analysis of microcystins and microcystin genes in 60–170-year-old dried herbarium specimens of cyanobacteria

Subsamples of cyanobacteria which had been stored as herbarium specimens at the Natural History Museum, London (BM), were analysed for the presence of microcystins and for genes involved in their biosynthesis using PCR. The samples had been collected worldwide between 1839 and 1950 and stored as dried specimens on paper, or between thin sheets of mica, under ambient conditions in the dark. Specimens for analysis were selected on the assumption that the chosen genera or species identified at the time of collection would have had a high potential for microcystin production based on current knowledge of the phylogeny of microcystin biosynthesis among the cyanobacteria. Of the 30 specimens analysed, 46% were positive for microcystins by high performance liquid chromatography with photodiode array detection and 83% were positive for the toxins according to microcystin immunoassay. Ninety seven percent of the specimens had ions which corresponded with known microcystins according to matrix-assisted laser desorption ionization time of flight mass spectrometry and 17% of the samples showed positive PCR bands for the mcyD gene for microcystin synthetase. These results demonstrate the potential for long-term survival of microcystins, and to a lesser extent of microcystin synthetase genes in herbarium specimens of dried cyanobacteria. They also offer the possibility for comparative studies on cyanotoxin occurrence at identifiable sites then and now, and of the use of archived cyanobacterial specimens in retrospective studies in the case of ecotoxicological investigations at the sampling locations.

Detection of various freshwater cyanobacterial toxins using ultra-performance liquid chromatography tandem mass spectrometry

Several freshwater cyanobacteria species have the capability to produce toxic compounds, frequently referred to as cyanotoxins. The most prevalent of these cyanotoxins is microcystin LR. Recognizing the potential health risk, France, Italy, Poland, Australia, Canada, and Brazil have set either standards or guidelines for the amount of microcystin LR permissible in drinking water based on the World Health Organization guideline of one μg/L of microcystin LR. Recently, the United States Environmental Protection Agency has begun to evaluate the occurrence and health effects of cyanotoxins and their susceptibility to water treatment under the Safe Drinking Water Act through the Contaminant Candidate List (CCL). A recent update of the Contaminant Candidate List focuses research and data collection on the cyanotoxins microcystin LR, anatoxin-a, and cylindrospermopsin. Liquid Chromatography/Tandem-Mass Spectrometry (LC/MS/MS) is a powerful tool for the analysis of various analytes in a wide variety of matrices because of its sensitivity and selectivity. The use of smaller column media (sub 2 μm particles) was investigated to both improve the speed, sensitivity and resolution, and to quantify the CCL cyanotoxins, in a single analysis, using Ultra-Performance Liquid Chromatography (UPLC ®) combined with tandem mass spectrometry. Natural waters and spiked samples were analyzed to show proof-of-performance. The presented method was able to clearly resolve each of the cyanotoxins in less than eight minutes with specificity and high spike recoveries.

Spatial and temporal distribution of the cyanotoxin microcystin-LR in the Lake Ontario ecosystem: Coastal embayments, rivers, nearshore and offshore, and upland lakes

Cyanotoxins, a group of hepatotoxins and neurotoxins produced by cyanobacteria, pose a health risk to those who use surface waters as sources for drinking water and for recreation. Little is known about the spatial and seasonal occurrence of cyanotoxins in Lake Ontario and other lakes and ponds within its watershed. Within the embayments, ponds, rivers, creeks, shoreside, and nearshore and offshore sites of Lake Ontario, microcystin-LR concentrations were low in May, increased through the summer, and reached a peak in September before decreasing in October. Considerable variability in microcystin-LR concentrations existed between and within habitat types within the Lake Ontario ecosystem. In general, the average microcystin-LR concentration was two orders of magnitude lower in embayment (mean = 0.084 μg/L), river (mean = 0.020 μg/L), and shoreside (mean = 0.052 μg/L) sites compared to upland lakes and ponds (mean = 1.136 μg/L). Concentrations in the nearshore sites (30-m depth) and offshore sites (100-m depth) were another order of magnitude lower (mean = 0.006 μg/L) than in the creek/river, bay/pond, and shoreside habitats. Only 0.3% (2 of 581) of the samples taken in Lake Ontario coastal waters exceeded the World Health Organization (WHO) Drinking Water Guideline of 1 μg microcystin/L for humans. In contrast, 20.4% (20 of 98) of the samples taken at upland lakes and ponds within the watershed of Lake Ontario exceeded WHO Guidelines. No significant relationship between nitrate and microcystin-LR concentrations was observed in Lake Ontario even though a significant positive relationship existed between phosphorus and phycocyanin and microcystin-LR concentrations. At an upland lake site (Conesus Lake) in the Ontario watershed, the development of a littoral Microcystis population was not observed despite high nutrient loading (P and N) into the nearshore zone, well-developed nearshore populations of filamentous Spirogyra and Zygnema, the occurrence of Dreissena spp., and the known occurrence of Microcystis and microcystin production in the pelagic waters of Conesus Lake.

CIANOBACTÉRIAS E CIANOTOXINAS EM RESERVATÓRIOS DO ESTADO DO RIO GRANDE DO NORTE E O POTENCIAL CONTROLE DAS FLORAÇÕES PELA TILÁPIA DO NILO (Oreochromis niloticus)

Normal 0 21 false false false MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Cyanobacteria blooms in reservoirs result in loss of water quality and negative effects to human health. To reduce these impacts the monitoring of the cyanobacteria and cyanotoxin occurrence as well as the application of measures to counteract the cyanobacteria blooms are made necessary. The manipulation of filter-feeding omnivorous fish stock, as Nile tilapia, has been proposed as an strategy for cyanobacteria bloom control. The present work aimed to evaluate: I) the presence of cyanobacteria (composition, density and biovolume by sedimentation technique) and cianotoxins (mouse bioassay) in five reservoirs located at the semi-arid region of Rio Grande do Norte state, in five sampling campaigns between September 2002 and March 2004; II) the per capita consumption rates of filamentous cyanobacteria by Nile tilapia through laboratory experiments using a natural population of cyanobacteria (experiment I) and a culture of Cylindrospermopsis raciborskii (experiment II), after the juveniles tilapias being exposed to a gradient of cyanobacteria biomass. The phytoplankton of the investigated reservoirs were dominated by cyanobacteria, including various toxigenic species ( C. raciborskii , Microcystis spp., Aphanizomenon e Anabaena circinalis ). Cianotoxins were present in three out of five reservoirs. The consumption rate of cyanobacteria ( ? g chlorophyll-a.fish -1 .day -1 ) by the tilapia was 0,29 in the experiment I and 0,5 in the experiment II. The human populations that use the studied reservoirs as drinking water supply are being potentially exposed to the negative effects of the cyanobacteria. The present research suggests that the stock of Nile tilapia to control cyanobacteria blooms is viable. Nevertheless, factors such as the ichthyo-eutrophication and the accumulation of cyanotoxins in the fish biomass should be taken into account before implementing a biomanipulation program.

Survey of cyanotoxins in New Zealand water bodies between 2001 and 2004

Contamination of drinking and recreational water bodies by toxic cyanobacteria is a significant water management issue in many countries. Until recently, knowledge of the occurrence of cyanotoxins and species responsible for cyanotoxin production in New Zealand was limited. In this study a total of 266 water and cyanobacterial mat samples collected from 227 different water bodies between 2001 to 2004 were analysed for cyanotoxins. Enzyme‐linked immunosorbent assays, liquid chromatography mass spectrometry, high performance liquid chromatography, and neuroblastoma assays resulted in the identification of microcystins/nodularins (102 samples from 54 different water bodies), anatoxin‐a (three samples from three different water bodies), and saxitoxins (48 samples from 41 different water bodies). The highest microcystin concentration was 36.5 mg litre‐1. The detection of anatoxin‐a is the first definitive report for New Zealand. Only low concentrations of saxitoxins were detected. Results indicate that cyanotoxins are more widespread in New Zealand water bodies than previously reported, in particular when cyanobacterial blooms or benthic cyanobacterial mats are present.

Cyanobacterial abundance and microcystin occurrence in Mediterranean water reservoirs in Central Spain: microcystins in the Madrid area

The occurrence and concentration of microcystins were analysed in sestonic samples from seven water reservoirs in the Madrid region (Spain) between July and November in two consecutive years (2002 and 2003). The data collected indicate that microcystins were present on several occasions in both years in all the reservoirs studied. The months of maximum risk for cyanotoxin occurrence were July, September and October, when Microcystis typically dominated the phytoplankton community. Four of the seven reservoirs exhibited conspicuous blooms, three of which were toxic. Of the samples in 2002 and 2003, 45% and 70%, respectively, contained microcystins (Mc). In four of the reservoirs, microcystin concentrations were higher than the WHO recommended limit for drinking water (1 µg Mc l−1) and, in one of the reservoirs (Santillana), its concentration, was extremely high (up to 70 µg Mc l−1). Concentrations above 1 µg l−1 were found during several months in this reservoir. Mc/chl a ratios in net-concentrated samples ranged from 0.0002 to 2.24 μg Mc (μg chl a)−1 with a mean value of 0.31 µg Mc (μg chl a)−1. From the data obtained we can conclude that M. aeruginosa is the main producer of microcystins in freshwaters from the Madrid region.

Monitoring Algal Toxins in Lake Water by Liquid Chromatography Tandem Mass Spectrometry

Microcystins (MCs) and cylindrospermopsin (CYL) are potent natural toxins produced by cyanobacteria (blue-green algae) that grow worldwide in eutrophic freshwaters and cause animal and human water-based toxicoses. The main purpose of this work has been assessing the contamination levels of some MCs and CYL in eutrophic Italian lake (Albano) water. To do this, we have developed an original analytical method involving MC extraction with a sorbent (Carbograph 4) cartridge. CYL is a highly polar compound that is scarcely retained by any sorbent material. To analyze this toxin, we directly injected 0.5 mL of filtered lake water into the liquid chromatography (LC) column. Analytes were quantified by LC coupled to tandem mass spectrometry in the multireaction monitoring mode. The recovery of five selected MCs added to an analyte free lake water sample at three different concentrations (50, 150, and 500 ng/L) ranged between 93 and 103% with RSD values no larger than 8%. Limits of quantification (LOQ) of the five MCs were within the 2-9 ng/L range, whereas the LOQ of CYL was 300 ng/L. The occurrence and abundance of cyanotoxins in Lake Albano was monitored over four months (Sept-Dec 2004) by analyzing water samples collected monthly at the center of the lake and at different depths (from 0 to -30 m). During survey and with the MS/MS system operating in the parent ion scan mode, we individuated two demethylated forms of MC-RR and one demethylated variety of MC-LR. Demethylated MC-RRs are known to be even more toxic than MC-RR toward zooplanktic grazers. CYL was the most-abundant toxin during the first three monitoring months. To the best of our knowledge, this is the first work reporting concentration levels of CYL in lake water.

Toxic potential of microcystin-containing cyanobacterial extracts from three Romanian freshwaters

The aim of this study was to characterise for the first time the toxin profile and in vivo/in vitro toxicological effects of cyanobacteria obtained from three Romanian freshwater blooms. Two strains of Microcystis aeruginosa were isolated from blooms occurring in different fish ponds. As well, a complex bloom sample obtained from a recreational lake area and dominated by Microcystis aeruginosa and Microcystis viridis was explored. The morphological identity of the cyanobacterial species could be confirmed by sequence analysis of the intergenic spacer region of the phycocyanin operon, PC-IGS. As well, both the strains and the field sample were confirmed to possess mcyA and mcyB genes, which correlated with the formation of several microcystins (MCYSTs). A number of cyanopeptolins and a new aeruginosin were also found. Despite these mixtures of compounds, in vivo as well as in vitro toxicological responses resembled those previously found for MCYST-LR. These include strong hepatotoxicity in mice with parenchymal disintegration and the emergence of haemorrhagic centres, a lack of responsiveness of human and fish cell lines most likely due to a lack of active transport systems, and a significant subcellular damage most prominent on the level of the lysosomes in primary hepatocytes of mice and rainbow trout. We thus conclude that the formation of blooms in the Romanian fish ponds and the recreational area may impact on animal and human health. A broader survey of cyanotoxin occurrence and related toxicity is necessary in Romania in order to assess the extent of this animal and human health hazard.

First report of the cyanobacterium Aphanizomenon ovalisporum Forti in two Greek lakes and cyanotoxin occurrence

Aphanizomenon ovalisporum is reported for the first time in Greece, in two warm, monomictic lakes. Aphanizomenon ovalisporum was dominant constituting 99 and 58% of the total cyanobacterial biomass in lakes Lysimachia and Trichonis, respectively. Trichomes were solitary (length 60-700 μm), were narrowed slightly at the ends, had a few terminal hyaline cells and had cells containing gas vesicles (length 2.5-6.9, width 2.4-5.1 μm). Heterocytes, spherical or ellipsoidal (length 4.4-10.5, width 2.41-5.1 μm) and akinetes (length 16.0-27.8, width 6.0-15.9 μm) were located in the middle of the trichome. High performance liquid chromatography (HPLC) analysis detected microcystin-LR (MC-LR) and a putative anabaenopeptin in the L. Lysimachia sample. The sestonic MC-LR concentration was 0.9 μg L -1 . The origin of MC-LR in L. Lysimachia is discussed. The other cyanobacteria present were Pseudanabaena sp. and Planktothrix mougeotii (1% of the total cyanobacterial biomass).