Daily Archives: April 1, 2015

How Should the “Precautionary Principle” Apply to Cyanobacterial Algal Blooms?

This paper is well written and a good review of our current understanding of cyanobacterial algal blooms.

The most likely exposure to harmful algal blooms is not from ingestion of drinking water, but skin contact in recreational waters. This has been known for quite some time.

“Human exposures to cyanobacteria and/or their harmful metabolites can occur in a number of ways. The most likely exposure is by recreating on waters where cyanobacterial accumulations are present.”

The authors raise an important question regarding application of the precuationary principle to what is referred to as cyanobacterial harmful algal blooms (CHAB). The last paragraph, last sentence states:

“As such, we propose a ‘guilty-until-proven-innocent-approach’ to CHAB management, consistent with the Precautionary Principle, in order to safeguard public health from both known and unknown cyanobacterial risks.”

When a cyanobacterial algal bloom occurs responsible water utilities take action to control them and remove harmful metabolites. Such actions have been taken by water suppliers for many decades. A ‘guilty-until-proven-innocent-approach’ sounds very noble. However such an action has negative consequences as well and may indeed be overly aggressive approach to regulatory action.

Timothy G. Otten & Hans W. Paerl  Curr. Health Effects of Toxic Cyanobacteria in U.S. Drinking and Recreational Waters: Our Current Understanding and Proposed Direction.  Current Environmental Health Reports (2015) 2:75–84 DOI 10.1007/s40572-014-0041-9

Cyanobacterial-derived water quality impairment issues are a growing concern worldwide. In addition to their ecological impacts, these organisms are prolific producers of bioactive secondary metabolites, many of which are known human intoxicants. To date only a handful of these compounds have been thoroughly studied and their toxicological risks estimated. While there are currently no national guidelines in place to deal with this issue, it is increasingly likely that within the next several years guidelines will be implemented. The intent of this review is to survey all relevant literature pertaining to cyanobacterial harmful algal bloom secondary metabolites, to inform a discussion on how best to manage this global public health threat.

Click here for paper (Open Access).