Contaminated soil carries risks to humans and pets

With increasing interest in urban agriculture, or in areas where arsenic based pesticides were historically applied, heavy metal testing in soils can be a valuable tool to assess risk factors affiliated with growing in potentially contaminated soil.

How are humans exposed to heavy metals? 

• The most well understood pathway is the direct ingestion or inhalation pathway. This is where heavy metal contaminated soil or dust is directly ingested from unwashed hands or produce or inhaled directly from soil dust.
• The indirect pathway, whereby heavy metals are taken into the plant via the roots, accumulated in the plant tissues, and then consumed, is a bit less understood.

While there has been recent research into certain agricultural crops ability to uptake heavy metals, most of the current heavy metal in soils recommendations are based on the direct exposure pathway. These current heavy metal level recommendations, along with best management practice guidance, should give growers and gardeners some decision making power when it comes to growing in a suspected contaminated soil.