Will fly ash used as a highway de-icer contaminate area water?
Peter answers: It certainly can. Fly ash often contains heavy metals and organic chemicals that tend to leach into water that passes over the ash (such as rainwater) and may then run into local waterways and supplies. But there is a distinction between fly ash from municipal incinerators, which burn a wide range of materials and therefore often contain a wider range of pollutants, and fly ash from coal boilers, which, depending on the type of coal, may contain fewer contaminants. There is also a distinction between actual fly ash, which is taken from the smoke, and bottom ash, which comes from the leftover embers. There is usually more bottom ash from an incinerator, and it is generally coarser, so it is more likely to be used on roads. Bottom ash generally contains smaller amounts of metals and organics. If runoff is rainwater, why is it bad? Peter answers: The rainwater itself isn’t bad, but as it runs over the ground it picks up all kinds of pollution, including oil, grease and heav
