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Freshwater Algal Toxins: Monitoring and Toxicity Profile

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A special issue of Toxins (ISSN 2072-6651). This special issue belongs to the section "Marine and Freshwater Toxins".

Deadline for manuscript submissions: closed (30 June 2020) | Viewed by 48533

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Prof. Dr. Ángeles Jos

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Department of Food Science, Toxicology and Legal Medicine, Faculty of Pharmacy, University of Sevilla, 41012 Sevilla, Spain
Interests: toxicology; risk assessment; food safety; cyanotoxins; microcystins; cylindrospermopsin
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Ana M. Cameán

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Dear Colleagues,

Climate change and human activities are affecting the dynamics of phytoplankton communities more and more. Among them, cyanobacterial abundance has increased disproportionately relative to other phytoplankton, and this trend is likely to continue in the coming decades. This fact has deleterious effects not only on ecosystem biodiversity but also adversely affects drinking water supplies, livestock watering, crop irrigation, aquaculture, etc. Thus, the proliferation of cyanobacterial blooms presents human and animal health risks due to the common production of potent toxins, cyanotoxins. However, in spite of the worldwide increasing occurrence of cyanotoxins, they are still underestimated in regulations, with Microcystin-LR as the main one (and in many cases, the only one) considered. However, risk management of cyanotoxins is only possible after a thorough risk evaluation, and for that purpose, toxicity and exposure data are required. Thus, occurrence and monitoring information is of key importance and the development and validation of more sensitive (multi)toxin analytical methods would also be welcome. On the other hand, with regard to toxicity, the scientific literature already shows a wide array of adverse effects cyanobacterial toxins can induce. However, the health consequences have not been investigated deeply enough, and there are many data gaps in different aspects such as toxicokinetics, toxicity of cyanotoxins mixtures, etc. Thus, the aim of this Special Issue is to gather new studies that could contribute in the risk evaluation process of cyanotoxins.

Prof. Dr. Angeles Jos
Prof. Dr. Ana M. Cameán
Guest Editors

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Keywords

microcystins
cylindrospermopsin
monitoring
toxicity
risk assessment
analytics

Published Papers (12 papers)

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Editorial

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3 pages, 215 KiB

Open AccessEditorial

Freshwater Algal Toxins: Monitoring and Toxicity Profile

by Angeles Jos and Ana M. Cameán

Toxins 2020, 12(10), 653; https://doi.org/10.3390/toxins12100653 - 13 Oct 2020

Cited by 5 | Viewed by 2007

Abstract

Climate change and human activities are more and more affecting the dynamics of phytoplankton communities [...] Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

Research

Jump to: Editorial, Review

15 pages, 2378 KiB

Open AccessArticle

Cyanobacterial Abundance and Microcystin Profiles in Two Southern British Lakes: The Importance of Abiotic and Biotic Interactions

by David M. Hartnell, Ian J. Chapman, Nick G. H. Taylor, Genoveva F. Esteban, Andrew D. Turner and Daniel J. Franklin

Toxins 2020, 12(8), 503; https://doi.org/10.3390/toxins12080503 - 05 Aug 2020

Cited by 9 | Viewed by 3180

Abstract

Freshwater cyanobacteria blooms represent a risk to ecological and human health through induction of anoxia and release of potent toxins; both conditions require water management to mitigate risks. Many cyanobacteria taxa may produce microcystins, a group of toxic cyclic heptapeptides. Understanding the relationships between the abiotic drivers of microcystins and their occurrence would assist in the implementation of targeted, cost-effective solutions to maintain safe drinking and recreational waters. Cyanobacteria and microcystins were measured by flow cytometry and liquid chromatography coupled to tandem mass spectrometry in two interconnected reservoirs varying in age and management regimes, in southern Britain over a 12-month period. Microcystins were detected in both reservoirs, with significantly higher concentrations in the southern lake (maximum concentration >7 µg L⁻¹). Elevated microcystin concentrations were not positively correlated with numbers of cyanobacterial cells, but multiple linear regression analysis suggested temperature and dissolved oxygen explained a significant amount of the variability in microcystin across both reservoirs. The presence of a managed fishery in one lake was associated with decreased microcystin levels, suggestive of top down control on cyanobacterial populations. This study supports the need to develop inclusive, multifactor holistic water management strategies to control cyanobacterial risks in freshwater bodies. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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6 pages, 420 KiB

Open AccessArticle

Absence of Cyanotoxins in Llayta, Edible Nostocaceae Colonies from the Andes Highlands

by Alexandra Galetović, Joana Azevedo, Raquel Castelo-Branco, Flavio Oliveira, Benito Gómez-Silva and Vitor Vasconcelos

Toxins 2020, 12(6), 382; https://doi.org/10.3390/toxins12060382 - 09 Jun 2020

Cited by 5 | Viewed by 2607

Abstract

Edible Llayta are cyanobacterial colonies consumed in the Andes highlands. Llayta and four isolated cyanobacteria strains were tested for cyanotoxins (microcystin, nodularin, cylindrospermopsin, saxitoxin and β-N-methylamino-L-alanine—BMAA) using molecular and chemical methods. All isolates were free of target genes involved in toxin biosynthesis. Only DNA from Llayta amplified the mcyE gene. Presence of microcystin-LR and BMAA in Llayta extracts was discarded by LC/MS analyses. The analysed Llayta colonies have an incomplete microcystin biosynthetic pathway and are a safe food ingredient. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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20 pages, 4191 KiB

Open AccessEditor’s ChoiceArticle

Cylindrospermopsin-Microcystin-LR Combinations May Induce Genotoxic and Histopathological Damage in Rats

by Leticia Díez-Quijada, Concepción Medrano-Padial, María Llana-Ruiz-Cabello, Giorgiana M. Cătunescu, Rosario Moyano, Maria A. Risalde, Ana M. Cameán and Ángeles Jos

Toxins 2020, 12(6), 348; https://doi.org/10.3390/toxins12060348 - 26 May 2020

Cited by 20 | Viewed by 3279

Abstract

Cylindrospermopsin (CYN) and microcystins (MC) are cyanotoxins that can occur simultaneously in contaminated water and food. CYN/MC-LR mixtures previously investigated in vitro showed an induction of micronucleus (MN) formation only in the presence of the metabolic fraction S9. When this is the case, the European Food Safety Authority recommends a follow up to in vivo testing. Thus, rats were orally exposed to 7.5 + 75, 23.7 + 237, and 75 + 750 μg CYN/MC-LR/kg body weight (b.w.). The MN test in bone marrow was performed, and the standard and modified comet assays were carried out to measure DNA strand breaks or oxidative DNA damage in stomach, liver, and blood cells. The results revealed an increase in MN formation in bone marrow, at all the assayed doses. However, no DNA strand breaks nor oxidative DNA damage were induced, as shown in the comet assays. The histopathological study indicated alterations only in the highest dose group. Liver was the target organ showing fatty degeneration and necrotic hepatocytes in centrilobular areas, as well as a light mononuclear inflammatory periportal infiltrate. Additionally, the stomach had flaking epithelium and mild necrosis of epithelial cells. Therefore, the combined exposure to cyanotoxins may induce genotoxic and histopathological damage in vivo. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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17 pages, 2577 KiB

Open AccessArticle

Effect of Zinc on Microcystis aeruginosa UTEX LB 2385 and Its Toxin Production

by Jose L. Perez and Tinchun Chu

Toxins 2020, 12(2), 92; https://doi.org/10.3390/toxins12020092 - 30 Jan 2020

Cited by 10 | Viewed by 3479

Abstract

Cyanobacteria harmful algal blooms (CHABs) are primarily caused by man-made eutrophication and increasing climate-change conditions. The presence of heavy metal runoff in affected water systems may result in CHABs alteration to their ecological interactions. Certain CHABs produce by-products, such as microcystin (MC) cyanotoxins, that have detrimentally affected humans through contact via recreation activities within implicated water bodies, directly drinking contaminated water, ingesting biomagnified cyanotoxins in seafood, and/or contact through miscellaneous water treatment. Metallothionein (MT) is a small, metal-sequestration cysteine rich protein often upregulated within the stress response mechanism. This study focused on zinc metal resistance and stress response in a toxigenic cyanobacterium, Microcystis aeruginosa UTEX LB 2385, by monitoring cells with (0, 0.1, 0.25, and 0.5 mg/L) ZnCl₂ treatment. Flow cytometry and phase contrast microscopy were used to evaluate physiological responses in cultures. Molecular assays and an immunosorbent assay were used to characterize the expression of MT and MC under zinc stress. The results showed that the half maximal inhibitory concentration (IC₅₀) was 0.25 mg/L ZnCl₂. Flow cytometry and phase contrast microscopy showed morphological changes occurred in cultures exposed to 0.25 and 0.5 mg/L ZnCl₂. Quantitative PCR (qPCR) analysis of selected cDNA samples showed significant upregulation of Mmt through all time points, significant upregulation of mcyC at a later time point. ELISA MC-LR analysis showed extracellular MC-LR (µg/L) and intracellular MC-LR (µg/cell) quota measurements persisted through 15 days, although 0.25 mg/L ZnCl₂ treatment produced half the normal cell biomass and 0.5 mg/L treatment largely inhibited growth. The 0.25 and 0.5 mg/L ZnCl₂ treated cells demonstrated a ~40% and 33% increase of extracellular MC-LR(µg/L) equivalents, respectively, as early as Day 5 compared to control cells. The 0.5 mg/L ZnCl₂ treated cells showed higher total MC-LR (µg/cell) quota yield by Day 8 than both 0 mg/L ZnCl₂ control cells and 0.1 mg/L ZnCl₂ treated cells, indicating release of MCs upon cell lysis. This study showed this Microcystis aeruginosa strain is able to survive in 0.25 mg/L ZnCl₂ concentration. Certain morphological zinc stress responses and the upregulation of mt and mcy genes, as well as periodical increased extracellular MC-LR concentration with ZnCl₂ treatment were observed. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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15 pages, 1359 KiB

Open AccessEditor’s ChoiceArticle

Isolation and Characterization of [D-Leu¹]microcystin-LY from Microcystis aeruginosa CPCC-464

by Patricia LeBlanc, Nadine Merkley, Krista Thomas, Nancy I. Lewis, Khalida Békri, Susan LeBlanc Renaud, Frances R. Pick, Pearse McCarron, Christopher O. Miles and Michael A. Quilliam

Toxins 2020, 12(2), 77; https://doi.org/10.3390/toxins12020077 - 23 Jan 2020

Cited by 12 | Viewed by 3209

Abstract

[D-Leu¹]MC-LY (1) ([M + H]⁺ m/z 1044.5673, Δ 2.0 ppm), a new microcystin, was isolated from Microcystis aeruginosa strain CPCC-464. The compound was characterized by ¹H and ¹³C NMR spectroscopy, liquid chromatography–high resolution tandem mass spectrometry (LC–HRMS/MS) and UV spectroscopy. A calibration reference material was produced after quantitation by ¹H NMR spectroscopy and LC with chemiluminescence nitrogen detection. The potency of 1 in a protein phosphatase 2A inhibition assay was essentially the same as for MC-LR (2). Related microcystins, [D-Leu¹]MC-LR (3) ([M + H]⁺ m/z 1037.6041, Δ 1.0 ppm), [D-Leu¹]MC-M(O)R (6) ([M + H]⁺ m/z 1071.5565, Δ 2.0 ppm) and [D-Leu¹]MC-MR (7) ([M + H]⁺ m/z 1055.5617, Δ 2.2 ppm), were also identified in culture extracts, along with traces of [D-Leu¹]MC-M(O₂)R (8) ([M + H]⁺ m/z 1087.5510, Δ 1.6 ppm), by a combination of chemical derivatization and LC–HRMS/MS experiments. The relative abundances of 1, 3, 6, 7 and 8 in a freshly extracted culture in the positive ionization mode LC–HRMS were ca. 84, 100, 3.0, 11 and 0.05, respectively. These and other results indicate that [D-Leu¹]-containing MCs may be more common in cyanobacterial blooms than is generally appreciated but are easily overlooked with standard targeted LC–MS/MS screening methods. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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21 pages, 2237 KiB

Open AccessEditor’s ChoiceArticle

Analysis of the Use of Cylindrospermopsin and/or Microcystin-Contaminated Water in the Growth, Mineral Content, and Contamination of Spinacia oleracea and Lactuca sativa

by Maria Llana-Ruiz-Cabello, Angeles Jos, Ana Cameán, Flavio Oliveira, Aldo Barreiro, Joana Machado, Joana Azevedo, Edgar Pinto, Agostinho Almeida, Alexandre Campos, Vitor Vasconcelos and Marisa Freitas

Toxins 2019, 11(11), 624; https://doi.org/10.3390/toxins11110624 - 28 Oct 2019

Cited by 26 | Viewed by 3952

Abstract

Cyanobacteria and cyanotoxins constitute a serious environmental and human health problem. Moreover, concerns are raised with the use of contaminated water in agriculture and vegetable production as this can lead to food contamination and human exposure to toxins as well as impairment in crop development and productivity. The objective of this work was to assess the susceptibility of two green vegetables, spinach and lettuce, to the cyanotoxins microcystin (MC) and cylindrospermopsin (CYN), individually and in mixture. The study consisted of growing both vegetables in hydroponics, under controlled conditions, for 21 days in nutrient medium doped with MC or CYN at 10 μg/L and 50 μg/L, or CYN/MC mixture at 5 + 5 μg/L and 25 + 25 μg/L. Extracts from M. aeruginosa and C. ovalisporum were used as sources of toxins. The study revealed growth inhibition of the aerial part (Leaves) in both species when treated with 50µg/L of MC, CYN and CYN/MC mixture. MC showed to be more harmful to plant growth than CYN. Moreover spinach leaves growth was inhibited by both 5 + 5 and 25 + 25 µg/L CYN/MC mixtures, whereas lettuce leaves growth was inhibited only by 25 + 25 µg/L CYN/MC mixture. Overall, growth data evidence increased sensitivity of spinach to cyanotoxins in comparison to lettuce. On the other hand, plants exposed to CYN/MC mixture showed differential accumulation of CYN and MC. In addition, CYN, but not MC, was translocated from the roots to the leaves. CYN and MC affected the levels of minerals particularly in plant roots. The elements most affected were Ca, K and Mg. However, in leaves K was the mineral that was affected by exposure to cyanotoxins. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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21 pages, 1580 KiB

Open AccessEditor’s ChoiceArticle

Meteorological and Nutrient Conditions Influence Microcystin Congeners in Freshwaters

by Zofia E. Taranu, Frances R. Pick, Irena F. Creed, Arthur Zastepa and Sue B. Watson

Toxins 2019, 11(11), 620; https://doi.org/10.3390/toxins11110620 - 26 Oct 2019

Cited by 17 | Viewed by 3370

Abstract

Cyanobacterial blooms increasingly impair inland waters, with the potential for a concurrent increase in cyanotoxins that have been linked to animal and human mortalities. Microcystins (MCs) are among the most commonly detected cyanotoxins, but little is known about the distribution of different MC congeners despite large differences in their biomagnification, persistence, and toxicity. Using raw-water intake data from sites around the Great Lakes basin, we applied multivariate canonical analyses and regression tree analyses to identify how different congeners (MC-LA, -LR, -RR, and -YR) varied with changes in meteorological and nutrient conditions over time (10 years) and space (longitude range: 77°2′60 to 94°29′23 W). We found that MC-LR was associated with strong winds, warm temperatures, and nutrient-rich conditions, whereas the equally toxic yet less commonly studied MC-LA tended to dominate under intermediate winds, wetter, and nutrient-poor conditions. A global synthesis of lake data in the peer-reviewed literature showed that the composition of MC congeners differs among regions, with MC-LA more commonly reported in North America than Europe. Global patterns of MC congeners tended to vary with lake nutrient conditions and lake morphometry. Ultimately, knowledge of the environmental factors leading to the formation of different MC congeners in freshwaters is necessary to assess the duration and degree of toxin exposure under future global change. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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22 pages, 10781 KiB

Open AccessEditor’s ChoiceArticle

Chronic Low Dose Oral Exposure to Microcystin-LR Exacerbates Hepatic Injury in a Murine Model of Non-Alcoholic Fatty Liver Disease

by Apurva Lad, Robin C. Su, Joshua D. Breidenbach, Paul M. Stemmer, Nicholas J. Carruthers, Nayeli K. Sanchez, Fatimah K. Khalaf, Shungang Zhang, Andrew L. Kleinhenz, Prabhatchandra Dube, Chrysan J. Mohammed, Judy A. Westrick, Erin L. Crawford, Dilrukshika Palagama, David Baliu-Rodriguez, Dragan Isailovic, Bruce Levison, Nikolai Modyanov, Amira F. Gohara, Deepak Malhotra, Steven T. Haller and David J. Kennedy Show full author list Hide full author list

Toxins 2019, 11(9), 486; https://doi.org/10.3390/toxins11090486 - 23 Aug 2019

Cited by 32 | Viewed by 6919

Abstract

Microcystins are potent hepatotoxins that have become a global health concern in recent years. Their actions in at-risk populations with pre-existing liver disease is unknown. We tested the hypothesis that the No Observed Adverse Effect Level (NOAEL) of Microcystin-LR (MC-LR) established in healthy mice would cause exacerbation of hepatic injury in a murine model (Lepr^db/J) of Non-alcoholic Fatty Liver Disease (NAFLD). Ten-week-old male Lepr^db/J mice were gavaged with 50 μg/kg, 100 μg/kg MC-LR or vehicle every 48 h for 4 weeks (n = 15–17 mice/group). Early mortality was observed in both the 50 μg/kg (1/17, 6%), and 100 μg/kg (3/17, 18%) MC-LR exposed mice. MC-LR exposure resulted in significant increases in circulating alkaline phosphatase levels, and histopathological markers of hepatic injury as well as significant upregulation of genes associated with hepatotoxicity, necrosis, nongenotoxic hepatocarcinogenicity and oxidative stress response. In addition, we observed exposure dependent changes in protein phosphorylation sites in pathways involved in inflammation, immune function, and response to oxidative stress. These results demonstrate that exposure to MC-LR at levels that are below the NOAEL established in healthy animals results in significant exacerbation of hepatic injury that is accompanied by genetic and phosphoproteomic dysregulation in key signaling pathways in the livers of NAFLD mice. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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19 pages, 3296 KiB

Open AccessEditor’s ChoiceArticle

Diagnosing Microcystin Intoxication of Canines: Clinicopathological Indications, Pathological Characteristics, and Analytical Detection in Postmortem and Antemortem Samples

by Amanda J. Foss, Mark T. Aubel, Brandi Gallagher, Nancy Mettee, Amanda Miller and Susan B. Fogelson

Toxins 2019, 11(8), 456; https://doi.org/10.3390/toxins11080456 - 03 Aug 2019

Cited by 21 | Viewed by 5787

Abstract

In the summer of 2018, six dogs exposed to a harmful algal bloom (HAB) of Microcystis in Martin County Florida (USA) developed clinicopathological signs of microcystin (MC) intoxication (i.e., acute vomiting, diarrhea, severe thrombocytopenia, elevated alanine aminotransferase, hemorrhage). Successful supportive veterinary care was provided and led to survival of all but one patient. Confirmation of MC intoxication was made through interpretation of clinicopathological abnormalities, pathological examination of tissues, microscopy (vomitus), and analytical MC testing of antemortem/postmortem samples (vomitus, blood, urine, bile, liver, kidney, hair). Gross and microscopic examination of the deceased patient confirmed massive hepatic necrosis, mild multifocal renal tubular necrosis, and hemorrhage within multiple organ systems. Microscopy of a vomitus sample confirmed the presence of Microcystis. Three analytical MC testing approaches were used, including the MMPB (2-methyl-3-methoxy-4-phenylbutyric acid) technique, targeted congener analysis (e.g., liquid chromatography tandem-mass spectrometry of MC-LR), and enzyme-linked immunosorbent assay (ELISA). Total Adda MCs (as MMPB) were confirmed in the liver, bile, kidney, urine, and blood of the deceased dog. Urinalysis (MMPB) of one surviving dog showed a high level of MCs (32,000 ng mL⁻¹) 1-day post exposure, with MCs detectable >2 months post exposure. Furthermore, hair from a surviving dog was positive for MMPB, illustrating another testable route of MC elimination in canines. The described cases represent the first use of urine as an antemortem, non-invasive specimen to diagnose microcystin toxicosis. Antemortem diagnostic testing to confirm MC intoxication cases, whether acute or chronic, is crucial for providing optimal supportive care and mitigating MC exposure. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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14 pages, 3673 KiB

Open AccessEditor’s ChoiceArticle

Exposure to the Harmful Algal Bloom (HAB) Toxin Microcystin-LR (MC-LR) Prolongs and Increases Severity of Dextran Sulfate Sodium (DSS)-Induced Colitis

by Robin C. Su, Thomas M. Blomquist, Andrew L. Kleinhenz, Fatimah K. Khalaf, Prabhatchandra Dube, Apurva Lad, Joshua D. Breidenbach, Chrysan J. Mohammed, Shungang Zhang, Caitlin E. Baum, Deepak Malhotra, David J. Kennedy and Steven T. Haller

Toxins 2019, 11(6), 371; https://doi.org/10.3390/toxins11060371 - 25 Jun 2019

Cited by 25 | Viewed by 5675

Abstract

Inflammatory Bowel Disease (IBD) represents a collection of gastrointestinal disorders resulting from genetic and environmental factors. Microcystin-leucine arginine (MC-LR) is a toxin produced by cyanobacteria during algal blooms and demonstrates bioaccumulation in the intestinal tract following ingestion. Little is known about the impact of MC-LR ingestion in individuals with IBD. In this study, we sought to investigate MC-LR’s effects in a dextran sulfate sodium (DSS)-induced colitis model. Mice were separated into four groups: (a) water only (control), (b) DSS followed by water (DSS), (c) water followed by MC-LR (MC-LR), and (d) DSS followed by MC-LR (DSS + MC-LR). DSS resulted in weight loss, splenomegaly, and severe colitis marked by transmural acute inflammation, ulceration, shortened colon length, and bloody stools. DSS + MC-LR mice experienced prolonged weight loss and bloody stools, increased ulceration of colonic mucosa, and shorter colon length as compared with DSS mice. DSS + MC-LR also resulted in greater increases in pro-inflammatory transcripts within colonic tissue (TNF-α, IL-1β, CD40, MCP-1) and the pro-fibrotic marker, PAI-1, as compared to DSS-only ingestion. These findings demonstrate that MC-LR exposure not only prolongs, but also worsens the severity of pre-existing colitis, strengthening evidence of MC-LR as an under-recognized environmental toxin in vulnerable populations, such as those with IBD. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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Review

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18 pages, 1791 KiB

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Microcystin Incidence in the Drinking Water of Mozambique: Challenges for Public Health Protection

by Isidro José Tamele and Vitor Vasconcelos

Toxins 2020, 12(6), 368; https://doi.org/10.3390/toxins12060368 - 02 Jun 2020

Cited by 16 | Viewed by 4304

Abstract

Microcystins (MCs) are cyanotoxins produced mainly by freshwater cyanobacteria, which constitute a threat to public health due to their negative effects on humans, such as gastroenteritis and related diseases, including death. In Mozambique, where only 50% of the people have access to safe drinking water, this hepatotoxin is not monitored, and consequently, the population may be exposed to MCs. The few studies done in Maputo and Gaza provinces indicated the occurrence of MC-LR, -YR, and -RR at a concentration ranging from 6.83 to 7.78 µg·L⁻¹, which are very high, around 7 times above than the maximum limit (1 µg·L⁻¹) recommended by WHO. The potential MCs-producing in the studied sites are mainly Microcystis species. These data from Mozambique and from surrounding countries (South Africa, Lesotho, Botswana, Malawi, Zambia, and Tanzania) evidence the need to implement an operational monitoring program of MCs in order to reduce or avoid the possible cases of intoxications since the drinking water quality control tests recommended by the Ministry of Health do not include an MC test. To date, no data of water poisoning episodes recorded were associated with MCs presence in the water. However, this might be underestimated due to a lack of monitoring facilities and/or a lack of public health staff trained for recognizing symptoms of MCs intoxication since the presence of high MCs concentration was reported in Maputo and Gaza provinces. Full article

(This article belongs to the Special Issue Freshwater Algal Toxins: Monitoring and Toxicity Profile)

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