http://www.digitaljournal.com/life/food/exploring-lead-risks-in-urban-farming/article/393309

Exploring lead risks in urban farming

Posted Jul 29, 2014 by Walter McDaniel
Urban farmer Ryan Kuck alleges that his garden was slowly poisoning his children in Philadelphia. Lead poisoning has often been a problem in United States and we'll explore the reasons behind this.
Sweeping buildings  construction and industry all helped create an amazing city in architecture. Unf...
Sweeping buildings, construction and industry all helped create an amazing city in architecture. Unfortunately it may also have contributed to high levels of metal in soil.
Ben Grey
Our story comes from anecdotal evidence in Modern Farmer. Kuck runs a major urban farm called Greensgrow. While he still runs the project he reported his concerns about his crops after his twins had high levels of lead in their blood which he asserts came from his project.
Cities such as Detroit have seen high levels of lead and other metals which lead to poisoning. With new technology we have seen these levels drop. Lower test scores are just one result of dangerous levels in many cities.
At their peak cities such as Detroit had massive industrialization without many safeguards. Over time air pollution sinks into soil and metals can also soak into the water people pour on plants. Produce can still grow under these circumstances and it becomes part of the plant itself.
All forms of soil carry this risk if they had higher levels of metal in the past. Interestingly some plants can clean these metals out of the soil if they are maintained properly. Farmers of all types should test their land if they think there is a risk of contamination.