What are toxic algae, and how dangerous are they really?

In this episode of AquaDiary, Ally breaks down the health risks of harmful algal blooms (HABs), including cyanotoxins like microcystin, how exposure can affect people and pets, why dogs can die within hours, what the health advisory limits are federally and by state, what toxic blooms mean for lakes and drinking water systems, how to find out if your state is monitoring for cyanotoxins, how to see if you're being exposed to toxins in your drinking water, and why public awareness still lags behind the science. She also explores emerging research into possible long-term neurological risks, including whether certain algae toxins may one day be linked to diseases like Alzheimer’s.

Topics covered: toxic algae, mattoon water crisis, harmful algal blooms (HABs), cyanobacteria, cyanotoxins, microcystin, anatoxin-a, BMAA, algae toxins, dog deaths from algae blooms, toxic lake water, harmful algal bloom health risks, cyanotoxins in drinking water, algae blooms and pets, lake water safety, tap water contamination, public health, water treatment, health advisories, emerging research, and environmental science.

References:

• Caller, T.A., et al. (2009). A cluster of amyotrophic lateral sclerosis in New Hampshire:

• A possible role for toxic cyanobacteria blooms. Amyotrophic Lateral Sclerosis, 10(Suppl. 2), 101–108.

• Cox, P.A., et al. (2016). Chronic exposure to BMAA may trigger Alzheimer's-like pathology in primates. Proceedings of the Royal Society B.

• Durden, W.N., et al. (2025). Alzheimer's disease signatures in the brain transcriptome of estuarine dolphins. Communications Biology, 8(1), 1400.

• Environmental Working Group. Tap water database — does your state monitor microcystin https://www.ewg.org/tapwater

• Garamszegi, S.P., et al. (2023). Detection of BMAA in postmortem olfactory bulbs of Alzheimer's disease patients. Toxicology Reports, 10, 392–400.

• IPM Newsroom. (2025, September 5). What to know about algal blooms after Mattoon's water crisis.
• NPR Illinois. (2025, September 15). Toxic bacteria shut down Mattoon's water supply.
• U.S. Environmental Protection Agency. (2015). Health advisory for microcystins (0.3 µg/L children; 1.6 µg/L adults). https://www.epa.gov
• World Health Organization. Guidelines for drinking-water quality. [Microcystin-LR guideline: 1.0 µg/L]

Links:

• EWG Tap Water Database (microcystin by state): https://www.ewg.org/tapwater
• NY HABs Tracker (harmful algal bloom advisories): https://www.dec.ny.gov/chemical/77118.html
• Find your Annual Drinking Water Report: Search [your town name] + 'annual drinking water report' or https://www.epa.gov/ccr
• Water filter — tested for microcystin removal (Berkey): https://amzn.to/4t25nPY
• Microcystin regulations by state: https://static.ewg.org/reports/2019/microcystin/img/EWG_Microcystins-StateReg_C02.pdf