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Cyanotoxins: A n Emerging Global Issue

Cyanotoxins: A n Emerging Global Issue. Kelly A Magurany, M.Sc., DABT Principal Research Scientist- Toxicology. August 1st, 2016. What are Cyanotoxins?. Cyanotoxins A large group of phycotoxins produced by certain species of cyanobacteria

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Cyanotoxins: A n Emerging Global Issue

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  1. Cyanotoxins: AnEmerging Global Issue Kelly A Magurany, M.Sc., DABT Principal Research Scientist- Toxicology August 1st, 2016

  2. What are Cyanotoxins? • Cyanotoxins • A large group of phycotoxins produced by certain species of cyanobacteria • Found intracellularly- released if cell dies or is lysed • Many are potent neurological, hepatic, and dermatological toxicants. • Microcystin-LR is the most well studied hepatotoxic cyanotoxin. It has also been classified as an IARC 2B carcinogen. • Cyanobacteria • Otherwise known as blue-green algae • Similar to bacteria, but photosynthesize like algae • Found worldwide, but prefer fresh and brackish waters Microcystis sp. Bloom- St Johns River, FL Photos courtesy of http://www-cyanosite.bio.purdue.edu/images/images.html

  3. Cyanobacterial Harmful Algal Blooms (CyanoHABs) • Influential factors • Increased water temperature (> 25C) • Light intensity • Long hydraulic retention time (>1 month) • Droughts (change in water chemistry) • Nutrient enrichment • Opportunistic changes in habitat, esp. competing bacteria or phytoplankton ( e.g., Asiatic mussels in Great Lakes) • Contaminants from effluent & storm water • Agricultural run-off (especially N and P) • Growth varies temporally- hourly to daily to seasonally & longer • Challenging to predict spatially • Influenced by geology, topography, weather, etc. • Concentration may be stratified and subject to rapid change (e.g., by wind) Microcystis sp. bloom Photo courtesy of http://www-cyanosite.bio.purdue.edu/images/images.html

  4. Occurrence Rates “…[the] frequency and geographic distribution of documented CyanoHABs seem to have dramatically increased in recent decades in the United States and globally…” ---Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health of the Joint Subcommittee on Ocean Science and Technology. Washington, DC

  5. US Detection Rates Courtesy of USGS, Beaver et al. 2014

  6. Select Midwest Detection Rates Courtesy of Graham 2004, 2006, 2009 via USGS 2014

  7. Incidents • Toledo, OH, August 2014 – “Do Not Drink” Advisory affecting potable water supply for > 500,000 people • Summer 2015 bloom, largest in 100 years Toledo Images courtesy of NOAA

  8. Global Blooms Baltic Sea, Europe 2016 Lake Atitlán, Guatemala, 2009 Lake Taihu, China, 2009 Africa, 2016 Murray River, Australia, 2016 700 kilometers affected Photos courtesy of NASA, NOAA, AU Murray-Darling Basin Authority, Dr. Hans Pearl, and the EU Space Agency

  9. Water Quality Guidelines Drinking Water • There are currently no federal regulations for cyanotoxins in drinking water • In 2015, US EPA issued Health Advisory Levels for certain of the most common cyanotoxins • Internationally the World Health Organization has set a provisional value for microcystin, Australia has set a guideline level, and Canada regulates for the same Recreational Water • Surface water is commonly used to irrigate crops and the quality of this water may influence crop contaminant levels • The FSMA Produce Safety Proposed Rule referenced US EPA Recreational Water Quality in the development of guidance for microbial hazards • Currently the US EPA Recreational water quality does not include specifications for cyanobacteria, although several US States have developed criteria.

  10. Challenges in the Event of an Incidence • Not always correlated with off-taste/odor compounds- geosmin and/or 2-methylisoborneol (MIB) • Toxins are stable to heat treatment, cannot be boiled off or processed out • “Do not drink/Do not boil” advisory • Conventional treatment techniques not always effective at higher cyanotoxin loads (60-99%, EPA 2015), and toxin levels may increase if algal cells lyse during treatment • Alternate water sources may not be readily available or in high enough volume • A proactive approach is necessary!

  11. Mitigation • Prevention of bloom formation • Control pollutant loads to reduce nutrient enrichment • Reduce hydraulic retention times • Addition of water mixing, aeration, or algaecides • Prediction of bloom formation • Proactive monitoring and treatment strategies • With effective treatment, cyanotoxin levels in potable supplies can be maintained < 1 ug/L

  12. Potential Impact on the Food Industry Not fully understood, key areas include: • Municipal water sources • Cyanotoxin accumulation in aquatic species globally at levels that indicate a human health concern (EFSA 2016) • Livestock drinking water & grazing on pastures closely associated with contaminated water sources- potential for meat/milk residuals • Contaminated agricultural water - preliminary data indicates potential for uptake by plants

  13. Evidence for Uptake by Plants *No data available for anatoxin-a, saxitoxin, or BMAA ** Not currently considered a reliable analytical method (EFSA, 2016)

  14. Summary • Cyanobacterial blooms are an increasingly prevalent issue • Exposure to cyanotoxins may occur through recreational activities, drinking water, and food consumption • Emerging evidence for agricultural irrigation waters indicates a potential for uptake of cyanotoxins into plants produced as food crops • Additional research should be considered, utilizing reliable analytical methods, to better characterize human health risk for exposure to cyanotoxins in foods

  15. Thank You!

  16. References 1) US EPA. Drinking Water Health Advisory for the Cyanobacterial Microcystin Toxins. EPA- 820R15100. June 2015. https://www.epa.gov/sites/production/files/2015-06/documents/microcystins-report-2015.pdf 2) Brooks, et al. Are Harmful Algal Blooms Becoming the Greatest Inland Water Quality Threat to Public Health and Aquatic Ecosystems? Environmental Toxicology and Chemistry, Vol. 35, No. 1, January 2016. DOI: 10.1002/etc.3220 3) AWWA. Webinar Program: “Preparing for Cyanotoxin Events: Learning from Recent Utility and State Experiences.” May 2016. http://www.awwa.org/portals/0/files/education/webcast/w160511handouts.pdf 4) USGS. U.S. Geological Survey Scientists Complete First Systematic Regional Survey of Algal Toxins in Streams of the Southeastern United States. May 19 2016. http://toxics.usgs.gov/highlights/2016-02-17-algal_toxins_in_streams.html 5) Zamyadi, et al. Fate of geosmin and 2-methylisoborneol in full-scale water treatment plants. Water Res. 2015 Oct 15;83:171-83. doi: 10.1016/j.watres.2015.06.038. Epub 2015 Jun 27. http://www.ncbi.nlm.nih.gov/pubmed/26143274 6) US EPA. EPA Evaluation of Chesapeake Bay 2014-2015 Milestone Progress and 2016-2017 Milestone Commitments to Reduce Nitrogen, Phosphorus and Sediment. 2016. https://www.epa.gov/sites/production/files/2016-06/documents/watershed_milestone_factsheet_final_0.pdf 7) Lopez, C.B., Jewett, E.B., Dortch, Q., Walton, B.T., Hudnell, H.K. 2008. Scientific Assessment of Freshwater Harmful Algal Blooms. Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health of the Joint Subcommittee on Ocean Science and Technology. Washington, DC. 8) EFSA. Review and analysis of occurrence, exposure and toxicity of cyanobacteria toxins in food. February 2016. https://www.efsa.europa.eu/en/supporting/pub/998e 9) NOAA/ National Center for Water Quality Research. Lake Erie Harmful Algal Bloom Early Season Projection. 28 June 2016, Projection 07. http://www2.nccos.noaa.gov/coast/lakeerie/bulletin/bulletin_current.pdf 10) http://earthobservatory.nasa.gov/Search/index.php?q=algal+blooms 11) http://www.water.nsw.gov.au/water-management/water-quality/algal-information; 12) Global Water Research Coalition. 2009. http://www.waterra.com.au/cyanobacteria-manual/Chapter1.htm#CYANOTOXIN2 13) World Health Organization. Guidelines for Safe Recreational Water Environments. 2003. http://www.who.int/water_sanitation_health/bathing/srwe1execsum/en/ 14) Kittler et al. Uptake of cyanobacterial toxin cylindrospermopsin in Brassica vegetables. Food Chemistry 133(3): 875-879. Aug 2012. http://www.sciencedirect.com/science/article/pii/S0308814612001598 15) Codd et al. Retention of Microcystis aeruginosa and microcystin by salad lettuce (Lactucasativa) after spray irrigation with water containing cyanobacteria. Toxicon. 37(8):1181-1185. August 1999. http://www.sciencedirect.com/science/article/pii/S004101019800244X 16) Chen et al. Accumulation and phytotoxicity of microcystin-LR in rice (Oryza sativa). Ecotoxicology and Environmental Safety. 76:193-199. February 2012. 17)USGS. Spatiotemporal Variability of CyanobacterialHarmful Algal Blooms with Respect to Changing Environmental Conditions. 2014 Water Mission Area Research Lecture Series 2014. http://ks.water.usgs.gov/cyanobacteria

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