Remediation to urban soils

Zombie Jac's Tip of the week:

Remediation to urban soils.

While the growth of Urban Farming and Urban Gardening (there is a difference) is booming now a days there should be a strong concern over the quality of the soil when doing ground planting.  Contamination of urban lots is common and often without proper remediation can lead to exposure to lead, mercury, zinc, arsenic, chromium, copper, dioxins and cadmium.

A soil contaminant is an element or chemical present in the soil at a level that could possibly pose health risks. In a few areas of the country, element levels may be naturally high. In many cases, human activities have increased the soil levels of many elements and chemicals and also spread them out more widely. Lead, cadmium, arsenic, zinc, and polycyclic aromatic hydrocarbons (PAHs) are contaminants commonly found in any urban environment. In addition, other contaminants can also be found in areas near former commercial or industrial properties. Table 1 lists sources of contamination that are commonly found on sites with a commercial or industrial history, such as where we are in Troy, NY.

So what can you do?  First see about getting your soil tested.  Cornell Cooperative Extension can provide testing as well as many garden centers provide soil testing.  Once you get a definitive answer on what is in your soil then you can go forward with a solid plan.

Remediation can be a significant undertaking and without proper testing you could also expose yourself to toxins just by allowing them to become airborne, for this reason if you suspect contamination we always recommend raised beds with a good weed barrier.  Other benefits to raised beds are high density growing, water conservation and weed control.  One of the most prevalent contaminants in urban environments is lead (Pb), but do to the fact that lead is not soluble (capable of being dissolved) exposure through most vegetables is minimal with the exceptions of root vegetables.  Exposure is more common through dirt dust, working the soil.  But lead is relatively simple to deal with.  The most common is compost.  A good quality, even home made compost can help remediate lead as well as many other contaminants through bonding.

Another option is separate planting.  Grow food in containers, raised beds while remediation through planting items like clover, ash plant, sunflowers, spinach and Indian mustard are considered hyperaccumulators and have the ability to take up soluble metals into their roots there by removing the contaminants up to 100 fold greater than other plants.  Typically harvested at the end of the growing season then have soil retested.

Care should be taken when ever considering urban growing but the benefits of urban growing far outweigh the risks when there are so many options to alleviate those risks.

Happy Gardening, farming and eating!