How toxic is coal ash? A laboratory toxicity case study.

Under a consent agreement among the Environmental Protection Agency (EPA) and proponents both for and against stricter regulation, EPA is to issue a new coal ash disposal rule by the end of 2014. Laboratory toxicity investigations often yield conservative estimates of toxicity because many standard test species are more sensitive than resident species, thus could provide information useful to the rule-making. However, few laboratory studies of coal ash toxicity are available; most studies reported in the literature are based solely on field investigations.

Effects of sediment containing coal ash from the Kingston ash release on embryo-larval development in the fathead minnow, Pimephales promelas (Rafinesque, 1820).

The largest environmental release of coal ash in US history occurred in December 2008 with the failure of a retention structure at the Tennessee Valley Authority Kingston Fossil Fuel Plant in East Tennessee. A byproduct of coal-burning power plants, coal ash is enriched in metals and metalloids such as selenium and arsenic with known toxicity to fish embryonic and larval life stages. The early development of fish embryos and larvae during contact exposures to river bottom sediments containing up to 78 % coal ash from the Kingston spill was examined in 7-day laboratory tests with the fathead minnow (Pimephales promelas).