A dump of coal ash will contain high levels of lead, mercury, cadmium, chromium, arsenic, and selenium. Which will either slowly leach into ground water and wat

A dump of coal ash will contain high levels of lead, mercury, cadmium, chromium, arsenic, and selenium. Which will either slowly leach into ground water and water ways (sometimes abruptly by dam failures) or must be kept contained forever. Heavy metal toxicity may be less dangerous than contamination with radioactive isotopes. But it's not clear to me that the waste rich in heavy metals is preferable if there's millions of times more of it. Because of the smaller scale, radioactive waste could just be put in a big building with some armed guards and regular inspections. Coal ash cannot be kept contained to that degree.