Office: (970) 564-5441 Cell: (970) 749-6791 Table A-1. Comparison of Cell Counts to Other Measurements of Harmful Algal Blooms from WHO (1999). Toxin Microcystin Anatoxin-A1 Chlorophyll a Relative Producing (µg/L) (µg/L) Health Risks Action Recommended Probability of Acute (µg/L) Health Risk algae Low <20,000 Negligible None Cell Issue caution Short-term advisory; effects Post CAUTION sign; e.g. skin Low to 4-20 NA 10-50 irritation, Moderate 100,000 Weekly sampling recommended illness Issue warning advisory; As above for – Post WARNING 10,000,00 low risk, and sign; Moderate 20-2,000 NA 50-5,000 Or potential for to High Reports long-term Weekly sampling of animal illness recommended illnesses or death Issue Danger >10,000,000 Advisory; or Post DANGER sign; As above for Visible moderate scum High >2,000 >5,000 risk, and Weekly sampling layer potential for recommended or acute Reports poisoning Consider Closure of illness Notes: From Oregon Public Health Advisory Guidelines 1 NA = None available
Office: (970) 564-5441 Cell: (970) 749-6791 Table A-1. Comparison of Cell Counts to Other Measurements of Harmful Algal Blooms from WHO (1999). Relative Probability of Acute Health Risk Toxin Producing algae Cell Microcystin (µg/L) Anatoxin-A1 (µg/L) Chlorophyll a (µg/L) Health Risks Action Recommended Low <20,000 Negligible None Low to Moderate 4-20 NA 10-50 Short-term effects e.g. skin irritation, illness Issue caution advisory; Post CAUTION sign; Weekly sampling recommended Moderate to High 100,000 – 10,000,00 Or Reports of animal illnesses or death 20-2,000 NA 50-5,000 As above for low risk, and potential for long-term illness Issue warning advisory; Post WARNING sign; Weekly sampling recommended High >10,000,000 or Visible scum layer or Reports of illness >2,000 >5,000 As above for moderate risk, and potential for acute poisoning Issue Danger Advisory; Post DANGER sign; Weekly sampling recommended Consider Closure Notes: 1 From Oregon Public Health Advisory Guidelines NA = None available
2017AlgaeResponsePlanFinal.docx