For information about HABs from the National Oceanic and Atmospheric Administration, visit their website here.
Ohio Department of Health has resources for Harmful Algal Blooms here.

Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals applied to many consumer goods to make them waterproof, stain resistant, or nonstick. PFAS are also used in products like cosmetics, fast food packaging, and a type of firefighting foam called aqueous film forming foam (AFFF) which are used mainly on large spills of flammable liquids, such as jet fuel. 

PFAS are classified as contaminants of emerging concern, meaning that research into the harm they may cause to human health is still ongoing. The most commonly studied PFAS are perfuorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA).

PFAS can enter drinking water at sites where they are made, used, disposed of, or spilled. PFAS can be found in the air near manufacturing facilities and can enter rainwater. PFAS are very mobile and can be transported through rainwater run-off and enter surface water (lakes, ponds, etc.) or seep through the soil and migrate into ground water (underground sources of drinking water). Because PFAS are very long-lasting and are not easily broken down by sunlight or other natural processes, they may remain in the environment for many years. 

If a public water system or your private well gets its water from a surface or ground water source that is contaminated with PFAS, and the water is not properly treated to remove the PFAS, the chemicals may be in your drinking water and can pass into your body when you ingest (drink or eat food cooked in) them.