A good pal who runs a water treatment plant in Ohio told an audience at a conference that he has canaries in his community. The reference is based on the proverbial “canary in a coal mine,” and his metaphor described certain water customers that were extremely sensitive to taste and odor changes. Phone calls from those customers, complaining of “muddy” or “earthy” water, could be an early indicator that he might have algae starting to grow in his reservoir.
His canaries are among the group of humans known to be extremely sensitive to the common taste and odor compounds called geosmins and MIB (2-methylisoborneol). Geosmins are responsible for the earthy smell after a summer rain, as they are commonly produced by microorganisms in soil and become volatile when the soil is wet. In water, geosmins and MIB can be produced by blue-green algae–the same blue-green algae that might make microcystin and other toxins.
Geosmins and MIB, however, are not toxic, and would have to be at extremely high concentrations to pose a threat to human health. The canaries sense them waaaaay before that point, and frankly so do the rest of us. A phone call from a canary, however, can tip off a drinking water operator that (s)he might need to adjust the treatment process, and might need to be on the lookout for more serious issues associated with algae, like toxins. A few companies (including Beagle Bioproducts) can confirm the presence of geosmins and MIB and can also test for toxins. That way, we can help plant operators continue to deliver the safe water the rest of us old buzzards have come to expect.