Current Needs for the Outreach and Extension Efforts Related to Contaminated Urban Soils.

Urban gardeners are interested in growing food on available land in their neighborhoods, including yards, vacant lots, parking strips, and community gardens.  Urban soils are often cut or filled, compacted, heterogeneous, and depleted in organic matter.  Some are contaminated from past activities. Urban gardeners need information and tools to evaluate their soils and remediate them as needed for food production.  Lead is a common contaminant in urban soils.  We sampled soils from the parking strips (leaded gasoline influence) and around the foundations (paint influence ) of 10 residences built between 1900 and 1920 in Tacoma WA, They were evaluated for lead using the Mehlich III test.  Mehlich results were multiplied by two to estimate total lead.  Soils from the parking strips averaged 46 mg/kg estimated total lead (range 22-107) while soils from around house foundations averaged 566 mg/kg lead (range 160-1050).  While nearly all lead levels were above background, lead levels in parking strips were not a concern for food gardening or contact with soil, while soils around most house foundations would be unsuitable for annual gardening.  We are also preparing a series of simple fact sheets focused on soils in urban food gardens.  Fact sheets completed or in progress to date include raised bed gardening, parking strip gardening, gardening in soils with elevated levels of lead and arsenic, and appropriate use of organic amendments.