Urban Chickens: Another Human Exposure Pathway for Soil Lead?.

Raising chickens in urban areas in the US and elsewhere is becoming increasingly common. While chicken eggs are a nutrient-dense food that can be part of a healthy diet, questions have arisen as to whether consuming urban chicken eggs can be an exposure pathway for lead due to its common presence in urban soils. We measured lead concentrations in chicken eggs from seven New York City community gardens and found that they were significantly associated (p < 0.005) with lead concentrations in the soil to which the chickens were exposed. Although egg lead concentrations we found were higher than those in market-basket eggs, estimates of health risk from consuming eggs with the lead concentrations we measured were generally low.  However, our study chickens were exposed to soil lead concentrations no higher than about 600 mg/kg, and considerably higher lead concentrations are not uncommon in urban soils in the US.  As lead exposure should be avoided when possible, efforts to reduce the transfer of lead to chicken eggs and associated exposure should be considered for urban backyards and community gardens that are used for raising chickens.  Best practices are proposed to achieve these outcomes.