Dinoflagellates are usually harmless, But can sometimes make toxic chemicals that leach into the tissue of shellfish.
Businesses fear that regulation would hamper such use; environmental groups say coal ash is full of toxic metals and tends to leach into groundwater.
Also, do not store water in plastic containers because the polychlorinated biphenyls (PCBs) can leach into the water.
For example, it remains unclear whether nanoparticles used in food packaging might migrate or leach into food or beverages.
Coal ash contains toxic heavy metals, including arsenic, cadmium, mercury and lead, which leach into water systems and get blown into the air during windy days.
A separate problem may be that some metals or chemicals leach into the brine.
