One of the biggest complications of urban agriculture is growing food in soils that previously had types of hazardous substance or contaminants on the property. Growing just near buildings has also led to serious concerns, due to the elevated levels of lead in the soils close to buildings where lead based paint has been used. Many urban agriculture communities especially in southern California have faced growing in soils that may have contaminants and this is because of limited areas to start urban farms in dense urban areas.
It is important to understand what is in your soil and how this can lead to ongoing exposure to people who are involved with the soil. One way to better understand what contaminants you have in your soil is by doing a soil test. Soil tests may be expensive and federal funding is available to certain properties by getting involved with brownfield grants.
The greatest risk for exposure to contaminants is by breathing in the dust or getting soil in your mouth. Another exposure pathway is edible plants that can accumulate and also take up contaminants from the soil. Root vegetables have the highest potential to store and accumulate contaminants
Using recycled containers is a solution to growing food in urban areas, and this method is used to help limit the amount of leached soil contaminants into the food crop. My leading question is, does growing in recycled containers such as tin cans or recycled car tires also have the potential to leach contaminants into the soil and eventually the crop?
Growing vegetables in old tires can contribute to three environmental risks, disease, chemical and fire. Although when we first think of car tires, you think rubber but in fact these rubber tires contain a lot of petrochemical plastics.
One article by Jerry Coleby-Williams states that car tyre rubber has toxins that leach into soils over many years. Tires contain chemicals such as aluminum, cadmium, chromium,copper, iron,magnesium,sulfur and high levels of zinc. Over time these toxic substances found in tires will contaminate the soil. The leaching rate can be affected by multiple factors such as areas with higher rainfall and soils with high acidity, as this would make the leaching rate faster. Leaching is one way growing vegetables in old tires contribute to disease, especially among kids who do not have a full grown immune system.
Fire is one of the three major environmental risks tires pose in urban agriculture, and it may not seem that possible but if you do unfortunately have a fire on your farm, tires can pose serious risks. EPA does not consider tire scraps as hazardous waste but in the occurrence of a fire the tires will cause a reaction where hazardous compounds can end up in soils or waters nearby. According to the U.S Environmental Protection Agency for every million tires consumed by fire, there is about 55,000 gallons of runoff oil that pollutes our ecosystem.
Urban agriculture faces many challenges when growing in such urban dense cities, and as mentioned one of the biggest problems is soil contaminants. There are many factors that can contribute to soil contaminants in an urban farm. You can personally reduce them by thinking about what products you are bringing on to your farm. Growing containers is one major way to limit the amount of contaminants that are being added to your soil. If you did get a soil contaminants test and decided not to plant directly into the ground, it is extremely important that you do not make the mistake of plant vegetables into containers that will eventually leach contaminants.
Refusing Potentially Contaminated Landscapes. (2011). Retrieved November 11, 2020, from https://www.epa.gov/sites/production/files/2014-03/documents/urban_gardening_fina_fact_sheet.pdf
Tire Fires | Scrap Tires. (n.d.). Retrieved November 10, 2020, from https://archive.epa.gov/epawaste/conserve/materials/tires/web/html/fires.html
Bradley, —, & Written ByDr. Lucy BradleyUrban Horticulture Professor and Extension SpecialistCall Dr. Lucy E-mail Dr. Lucy Horticultural Science NC State Extension. (2019, February 22). There Are Better Options Than Using Tires in the Garden. Retrieved November 10, 2020, from https://gardening.ces.ncsu.edu/2019/02/there-are-better-options-than-using-tires-in-the-garden/
Urban agriculture: The potential and challenges … – Agronomy. (n.d.). Retrieved November 13, 2020, from https://www.agronomy.org/news/science-news/urban-agriculture-potential-and-challenges-producing-food-cities