The Encyclopedia of Earth (EoE) is an electronic reference about the Earth, its natural environments, and their interaction with society. The EoE is a free, expert-reviewed collection of content contributed by scholars, professionals, educators, practitioners and other experts who collaborate and review each other's work. The content is presented in a style intended to be useful to students, educators, scholars, professionals, as well as to the general public.

The Environmental Contaminants Encyclopedia, last updated in 1998, summarizes information about 118 environmental contaminants and serves as a quick reference for determining whether or not concentrations are above levels that might affect living things. The encyclopedia includes information related to fish, wildlife, invertebrates, and other non-human living resources.