why are batteries harmful to the environment when they are thrown in the garbage?

Alecia Kaehler: Batteries contain heavy metals such as mercury, lead, cadmium, and nickel, which can contaminate the environment when batteries are improperly disposed of. When incinerated, certain metals might be released into the air or can concentrate in the ash produced by the combustion process.Batteries may produce the following potential problems or hazards:Pollute the lakes and streams as the metals vaporize into the air when burned.Contribute to heavy metals that potentially may leach from solid waste landfills.Expose the environment and water to lead and acid.Contain strong corrosive acids.May cause burns or danger to eyes and skin.In landfills, heavy metals have the potential to leach slowly into soil, groundwater or surface water. Dry cell batteries contribute about 88 percent of the total mercury and 50 percent of the cadmium in the municipal solid waste stream. In the past, batteries accounted for nearly half of the mercury used in the United States and over! half of the mercury and cadmium in the municipal solid waste stream. When burned, some heavy metals such as mercury may vaporize and escape into the air, and cadmium and lead may end up in the ash....Show more