Thursday, 16 April 2015

Urban Gardens in Danger From Proximity Contamination

Proximity Contamination is a major problem for gardens in urban areas. Contamination occurs when lead dust and chips move through the air and settle in the proximity. Contaminated soil can produce crops that are dangerous to consume. Although lead is naturally present in all soil, it is usually found in low levels (10-30 ppm). Levels found in urban areas are often much higher, ranging from 100ppm-1000ppm. Proximity contamination stems from many sources:
  • paint chips from older buildings (loosened by chipping, blasting, and peeling)
  • leaded gasoline combustion
  • scrap disposal containing lead - pipes, roofing, batteries
  • tire and vehicle debris
Urban areas are at a higher risk for proximity contamination because of the abundance of highly traveled roads, old buildings, and industrial buildings. Gabriel Filipelli, Ph.D., (earth sciences professor and international leader in the field of medical geology) advises that people study maps of their area and determine potential risks before they garden. Soil can also be tested, and the following guidelines should be used:
  • For levels below 200ppm (no or low-level risk), crops can be planted, but gardeners should use a high phosphate fertilizer.
  • For levels between 200ppm -500ppm (medium risk), ground soil should be covered, and crops planted in raised beds. Mulch should be placed between beds to reduce the risk of contamination from ground soil.
  • For levels over 500ppm (high risk), extreme caution is required due to likely pollutants from both the ground and air. While fruit trees may be safe, root plants require extreme care. Raised plant beds are a must, and mulching between beds and 10 feet around the perimeter of the garden is essential.
Proximity contamination is a serious problem for gardeners. Many Americans are working hard to live a healthier lifestyle, and embracing the idea of growing their own produce to avoid pesticides and chemicals found in grocery store fruits and vegetables. Please feel free to contact us to learn more about protecting your family from lead hazards.

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