Simplicity has an allure. When faced with complex topics, a degree of uncertainty and nuance, many people want direct guidance on whether something is safe or dangerous, right or wrong, good or bad. In reality, few things lend themselves to clear lines of demarcation and require some research, thought and contemplation to understand. The degree of threat posed by the presence of cyanobacteria in our ponds is a prime example of the hazards of relying on a public information system that conveys that things are either wonderful or horrible.
The Massachusetts Department of Public Health (MDPH) has standards that it relies upon to advise local health agents seeking their advice. Those standards essentially have three triggers that warrant an alert about potentially toxic cyanobacteria blooms: a measured cell count of more that 70,000 cyanobacteria cells in a given sample, a measured toxin level that exceeds MDPH guidelines of 8 ug/l for microcystin and 60 ug/l for anatoxin, and/or a significant visible scum layer. Absent any of those standards being tripped, there is no basis for exercising caution in the MDPH framework; there is either a problem or there is not.
Easy, right? No, not really. Just ask the woman whose dog is suspected of dying from exposure to cyanobacteria in the Charles River a few weeks ago what she thinks.
Not seeing the Charles River on the MDPH list of waters restricted by cyanobacteria levels, she allowed her dog to swim in the Charles west of the metropolitan Boston area. Due to a lack of routine monitoring and a warning system that is binary, this informed consumer of information did not have any indication that caution was warranted.
APCC’s system of routine monitoring of roughly 150 ponds, and our reporting of results using three tiers: Acceptable, Restriction Warranted and Potential for Concern, provides nuance missing in the statewide approach. Our intent behind having the additional category of Potential for Concern is based on our understanding that cyanobacteria populations are dynamic and that there are indicators that a surge in cyanobacteria density may result a full bloom—information the public should be given.
To be clear, our Potential for Concern category is not a public health advisory restricting access (those can only be issued by towns or MDPH); it is a flag that potential users of a pond may wish to exercise caution and use their judgement in deciding if using a pond is appropriate for them and their pets.
APCC’s website provides a lot of detailed information to help people make informed decisions about freshwater recreation.
As much as many in the regulatory business want to be able to provide definitive guidance to the public on cyanobacteria conditions, the behavior of cyanobacteria and the current limitations on constant and real time monitoring remain obstacles yet to be overcome.
APCC’s practice has been, and will continue to be, to provide information that accounts for the uncertainty and nuance inherent in dealing with cyanobacteria to the public for use in individual decision making. We believe that our current approach strikes the right balance, reflecting local authority to make public health determinations (those official warnings are always on our map) while alerting people to use caution when conditions indicate that a bloom of concern could be on the horizon.
While no system is foolproof, I am guessing that the people with dogs in the Charles River area wish that a system like ours was more widely available.
