Digging Deeper: Unearthing the Importance of Soil Lead Screening

Digging Deeper: Unearthing the Importance of Soil Lead Screening

Allegheny County Conservation District (ACCD) is celebrating World Soil Day with a look at the Urban Soils Program’s impact in 2023. 

World Soil Day is an opportunity to reflect on and celebrate “the importance and relationship between soil and water in achieving sustainable and resilient agrifood systems,” according to the United Nations. ACCD is proud to contribute to essential work taking place in the Pittsburgh region through the Urban Soils Program. 

Urban Soil Round Up

ACCD’s Urban Soils Program works with citizens and community partners to better understand the challenges of working with urban soil in farm, garden, and greenspace projects. While often overlooked in urban environments, soil plays a central role in the functioning of healthy towns and cities. The Urban Soils Program focuses on lead and contaminant research, soil screening outreach, and grower technical assistance. 

Soil Lead Screening Events 

ACCD rounded out this year with four successful soil lead screening events. During these events, approximately 150 Allegheny County residents had soil samples analyzed for lead, providing a valuable opportunity for backyard gardeners to learn about reducing the risk of exposure to soil contaminants.  

Residents who missed the soil lead screening events can check ACCD’s Events webpage to stay up to date with future screening events. 

Photo: ACCD teamed up with Grow Pittsburgh, Pennsylvania Department of Health, Women for a Healthy Environment and Agency for Toxic Substances and Disease Registry to offer real-time results and one-on-one consultation in 2023. 

Site Visits 

In addition to soil screening events, ACCD staff completed 11 site visits to local urban farms, community gardens, and green space projects, including numerous Adopt-A-Lot sites, to educate on the importance of soil health, demonstrate sample techniques and safety guidelines, screen soil samples for lead, map site data, and, finally, provide technical assistance to improve site conditions.  


Photo: Site visits include anlysis of multiple soil samples to develop a map of lead levels across a property. 

Year in Review 

Since the beginning of the 2023 growing season, ACCD has screened 953 soil samples for lead using XRF analysis. With soil lead testing from traditional laboratories costing an average of $30 or more, ACCD’s free soil screening service provided an estimated $28,590 worth of services to the Allegheny County community. 

Digging into the Importance of Soil Screening

The backyard gardeners, urban farmers, community garden leaders, and green space stewards that participate in the Urban Soils Program receive soil lead concentration results in terms of μg/g (micrograms per gram), mg/kg, or ppm (parts per million), all of which are equivalent units of measurement. Interpreting soil lead results can be challenging as no single threshold defines acceptable levels of lead in soil.  

ACCD utilizes the chart below to indicate the degree of risk associated with various soil lead concentrations in Allegheny County. Beyond results, ACCD provides essential educational resources and technical assistance for Allegheny County residents to accurately interpret and act on their results to reduce risk of exposure to soil contaminants. 

Soil Lead Levels