View Full Table | Close Full ViewTable 1.

Total soil lead concentrations of the Michigan Avenue vacant lot in the spring of 2009.

 
Soil sample Total lead
mg/kg
1 288
2 254
3 335
4 173
5 252
6 141
7 183
8 185
Average 226



View Full Table | Close Full ViewTable 2.

Average total soil lead concentrations of the Michigan vacant lot before and after the addition of compost in the spring of 2009.

 
Before or after adding compost Average total soil lead
mg/kg
Before adding compost 245 ± 21
After adding compost 145 ± 20



View Full Table | Close Full ViewTable 3.

Common urban soil contaminants and their sources (modified from Angima and Sullivan, 2008; USEPA, 2012, 2013).

 
General source Examples of previous site uses Specific contaminants
Paint (before 1978) old residential buildings; mining; leather tanning; landfill operations; aircraft component manufacturing lead
High-traffic areas or near roadways next to trafficked roadways or highways; near roadways built before leaded fuel was phased out lead, zinc, polycyclic aromatic hydrocarbons (PAHs)
Treated lumber lumber treatment facilities; structures built with treated lumber arsenic, chromium, copper, creosote
Burning wastes landfill operations PAHs, dioxins
Contaminated manure copper, zinc salts added to animal feed copper, zinc
Coal ash coal-fired power plants; landfills; homes with coal furnaces arsenic, selenium, cadmium, sulfur
Biosolids wastewater treatment plants; agriculture cadmium, copper, zinc, lead, persistent bioaccumulative toxins (PBTs)
Petroleum spills gas stations; residential/commercial/industrial uses (anywhere an aboveground or underground storage tank is or has been located) PAHs, benzene, toluene, xylene, ethyl benzene
Pesticides widespread pesticide use, such as in orchards; pesticide formulation, packaging, and shipping lead, arsenic, mercury, dichlorodiphenyltrichloroethane (DDT), chlordane, and other chlorinated pesticides
Commercial or industrial site use PAHs, petroleum products, solvents, lead, and other heavy metals (such as cadmium, arsenic, chromium, lead, mercury, and zinc)
Dry cleaners stoddard solvent and tetrachloroethene
Metal finishing operations metals and cyanides



View Full Table | Close Full ViewTable 4.

Recommended gardening practices based on results of soil test for lead, modified from Angima and Sullivan, 2008. The modification is the addition of the 250 to 400 category, which was added because of concerns specific to root crops (Ganga Hettiarachchi, personal communication, 25 Oct. 2013).

 
Amount of lead Gardening practice
Less than 50 mg kg–1 Little or no lead contamination in soil. No special precautions needed.
50 to 250 mg kg–1 Some lead present from human activities. Grow any vegetable crops. Choose gardening practices that limit dust or soil consumption by children.
250 to 400 mg kg–1 Do not grow root crops. Choose gardening practices that limit dust or soil consumption by children.
400 to 1200 mg kg–1 Do not grow root crops and low-growing (difficult to clean) leafy vegetables. Choose gardening practices that limit dust or soil consumption by children.
Greater than 1200 mg kg–1 Not recommended for vegetable gardening. Mulch and plant perennial shrubs, groundcover, or grass. Use clean soil in raised beds or containers for vegetable gardening.