Cyanobacterial toxins Workshop developed by RCAP/AWWA and funded by - PDF document

Cyanobacterial toxins Workshop developed by RCAP/AWWA and funded by the USEPA Learning Objectives • Have a basic understanding of how, when and why cyanobacteria toxins occur • Know when you need to take action • Be able to make informed about how to limit exposure to cyanotoxins Agenda • Understanding cyanobacterial toxins – Terms, regulations – Impacts – How they grow • Monitoring • Taking action – Prevent blooms from occurring – Removal of intact cyanobacteria – Treatment for toxins – Create an action plan 1 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Evaluating cyanotoxin contamination risk A Water Utility Manager’s Guide to Cyanotoxins (2015) • Self ‐ assessment helps determine risk level • Assesses three areas  source water monitoring  source water quality  cyanobacteria presence during treatment process Terminology • Harmful Algal Blooms (HABs) • Cyanobacteria • Cyanotoxins Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015 Harmful algal blooms (HABs) • Rapid increase or accumulation in the population of algae • Can refer to different types of algal bloom – Cyanobacteria – Green algal – Red tide (marine) Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015 2 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Cyanobacteria • “Blue-green algae” • Naturally found in surface water • Can rapidly multiply • Can produce dense www.epa.gov mats What are cyanotoxins? • Toxins produced by cyanobacteria – Contained within cyanobacteria cells • Usually released into water during cell rupture or cell death Classes of toxins • Microcystins: • Cylindrospermopsin • Anatoxins • Saxitoxins Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015 3 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

EPA estimates that between 30 to 48 million people using drinking water from lakes and reservoirs may be vulnerable to cyanotoxins EPA Recommendations for Public Water Systems to Manage Cyanotoxins in Drinking Water , 2015 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015 Federal Regulations • Safe Drinking Water Act, Clean Water Act – Currently, no federal regulations address cyanobacteria and their toxins Federal Regulations (cont.) • Contaminant Candidate List (CCL) – List of potential drinking water contaminants that are currently unregulated (not all- inclusive) – Identifies contaminants in need of additional study to determine whether or not they require regulation under the Safe Drinking Water Act 4 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

EPA’s Unregulated Contaminant Monitoring Rule 4 (2018 -2020) • Covers all systems with populations > 10,000 and 800 randomly selected small systems • Lists unregulated contaminants to be monitored by public water systems • Includes 10 cyanotoxins (9 cyanotoxins and 1 cyanotoxin group) EPA Drinking Water Health Advisories (HAs) • Young children more • Microcystins susceptible • Cylindrospermopsin Age Microcystins Cylindrospermopsin Children under 6 0.3 µg/L 0.7 µg/L years old 6 year old through 1.6 µg/L 3.0 µg/L adults State guidance values for drinking water 5 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Knowledge Checkpoint The Safe Drinking Water Act (SDWA) and the Clean Water Act regulate contaminant levels for cyanobacteria and cyanotoxins in drinking water. True or False? Cyanotoxins and human health • Can be acute or chronic • Liver, nervous system, and gastrointestinal system impacts • Range from a mild skin rash to serious illness or death Human exposure to cyanotoxins can occur in several ways • Ingesting contaminated water or fish • Skin contact with contaminated water • Inhaling or ingesting aerosolized toxins 6 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Other potential water quality issues • Taste and odor issues • Increased raw water turbidity • Increased disinfection byproduct precursors Other impacts of cyanobacteria • Adverse ecosystem impacts from hypoxia • Drinking and recreational water quality concerns • Economic losses Challenges for water utilities • Increase operational costs • Develop and implement cost effective methods to reduce blooms in source waters • Prevent, predict, analyze, monitor, and treat toxins • Determine how to communicate risk to the public 7 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Knowledge Checkpoint Describe some of the negative impacts of cyanobacterial blooms Cyanobacteria types • Most common genera: Anabaena Microcystis Planktothrix M57 Algae: Source to Treatment, First Edition Initial indicators of cyanobacterial bloom • Surface water discoloration (a red, green, or brown tint) • Thick, mat-like accumulations on the shoreline and surface • Fish kills 8 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Early warning signs of a cyanobacteria bloom • Increases in algal counts and turbidity • Strengthening or weakening of the thermocline – i.e. when turnover is beginning to take place • Increases in pH Leading factors causing blooms • Excess nutrients (nitrogen and phosphorus) • Slow moving surface water • Elevated water temperature Variation in cyanobacteria blooms • Does not always mean cyanotoxin issue – Multiple cyanobacteria strains in a single bloom – Not all cyanobacteria are capable of producing cyanotoxins 9 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Discussion Question • How would you recognize if a bloom is occurring? What would you do, who would you report it to? Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015 Knowledge Checkpoint Which of these is not an early warning indicator for a cyanobacteria bloom? a. The water turns a red, brown, or green color b. Increases in turbidity c. Increased light penetration d. Fall or spring turnover is about to take place Source water monitoring Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015 10 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Cyanobacteria & Cyanotoxin monitoring • Frequent, detailed, specific • Different intake depths/location, if available Routine monitoring • Visual inspection • Cell counts • Measure Chlorophyll a Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015 Common laboratory methods for cyanotoxins • Enzyme–linked immunosorbent assays ( ELISA ) - Screening • High performance liquid chromatographic methods ( HPLC ) with: – ultraviolet/photodiode array detectors ( UV/PDA ) – mass spectrometric ( MS, MS/MS ) 11 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Collecting water samples for toxin analysis • Collection – Store samples in amber containers to minimize exposure to sunlight • Quenching – Quench with sodium thiosulfate or ascorbic acid • Chilling – Place on ice, sample freezing may be appropriate to extend holding times What can you do? 1. Prevent a bloom from occurring 2. Remove cyanobacteria intact 3. Treat for toxins Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015 Effective preventative measures • Control anthropogenic influences that promote blooms (leaching and runoff of excess nutrients) • Water column mixing • Increasing water flow • Adjust depth of water intake 12 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Treatment Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015 Treatment for cyanotoxins • The majority of toxins are contained within cyanobacteria cells. (intracellular) • If possible, removal cyanobacteria without disrupting cells • More difficult to remove (extracellular) toxins in the water Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015 Treatment: intracellular cyanotoxins • Conventional water treatment – flocculation, coagulation, sedimentation and filtration • Flotation • Membranes • Preoxidation – May rupture cyanobacteria cells releasing the cyanotoxin to the water column. 13 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015

Intracellular treatment processes A Water Utility Manager’s Guide to Cyanotoxins , 2015, AWWA and Water Research Foundation Treatment: extracellular cyanotoxins • Conventional water treatment usually not effective • Activated carbon: powdered (PAC) or granular (GAC) • Chlorination is dependent on cyanotoxin Extracellular treatment processes A Water Utility Manager’s Guide to Cyanotoxins , 2015, AWWA and Water Research Foundation 14 Developed by AWWA in partnership with RCAP and funded by USEPA, Published 2015