A while back I found out the whole story about why Beluga whales were washing up on the shores of the St. Lawrence around Montreal--whales whose carcases were so contaminated with toxins that they had to be handled as toxic waste. Turns out it had to do with farmers in the American Midwest applying fertilizer to their fields. Excess nitrogen and phosphorus was washing into the rivers in the (rather immense) Mississippi catchment basin, concentrating in the waterways, spilling out into the Gulf where it was creating a dead zone. Algae from the dead zone found their way up the Atlantic coast in blooms, generating the neurotoxin found in red tide. Various predators concentrated the toxin up the food chain as the bloom moved north, finally resulting in dead whales in the St. Lawrence. Everything is connected.
 |
| Lake Erie photo via National Oceanic Service |
As I write this, Toledo, Ohio, is under a "do not drink" order for their municipal water supply. The reason? Contamination with
microcystin, a toxic by-product of blue-green algal blooms. Toledo draws its drinking water from Lake Erie (above, showing algal blooms visible
from space), along with 11 million other people.
 |
microcystin-LR molecule via Toxmais,
mostly because it's so frickin' cool! |
Cyanobacteria produce microcystins, and when they bloom, there's enough of the toxins (particularly microcystin-LR, the most toxic of the group) to affect humans drinking the water. Standard water treatment doesn't affect the presence of the toxin, or its toxicity.
