Cyanobacteria in Lakes (new ROE indicator post external peer review)
SUMMARY OF RESPONSE TO REVIEWERS
All three reviewers recommended the indicator for inclusion with suggested modifications. Modifications included minor clarifications to the indicator text and technical documentation. A few reviewers mentioned the need to tie this indicator to human health or environmental endpoints. At this point, we are unable to quantify the human health or environmental effects using the current data source (CyAN). We also do not have a national, peer-reviewed dataset for these related endpoints. One reviewer asked whether comparisons could be drawn (or analyses be done) across states, regions, or lakes, but that is beyond the scope of what the ROE offers. The most significant change made was to remove cyanobacteria magnitude from the indicator dataset and exhibits based on reviewers’ comments. The reason for omitting magnitude is its inconsistency with the latest World Health Organization (WHO) guidance (released March 8, 2021). In March 2021, WHO changed its exposure risk levels from cyanobacteria cell density to biomass and toxin concentrations. As a result, the cyanobacteria magnitude metric (in units of cyanobacteria cell density) no longer represents the magnitude of cyanobacteria exposure risk. Exhibit 3 (magnitude) data is no longer supported by the WHO or EPA’s Office of Water.