The legacies of preurban land uses are typically masked by current conditions, but the residual soil effects from former human activities may complicate our understanding of urban restoration. Past mining and industrial and waste disposal prior to urbanization, e.g., may be responsible for elevated soil metals that pose both ecological and human health risks. In addition to being directly toxic to terrestrial and aquatic biota heavy metals can reduce metabolism of soil microbes and microfauna, alter soil food webs, and decrease decomposition rates, shifting biogeochemical cycling of urban soils. However, not all preurbanization land use depletes soil resources. Historic agriculture doubled the soil C, N, and ion concentrations in soils of Phoenix, Arizona, compared to urban soils with no legacy of agriculture Biological waste disposal associated with preurban human settlements are known to increase topsoil depth and enhance soil fertility