Review of Urban Soil Lead Remediation Literature
By Dr. Mark A. S. Laidlaw
Urban soils in many communities in the United States and internationally have been contaminated by lead from past use of lead additives in gasoline/petrol, deterioration of exterior paint, emissions from lead smelters and battery recycling and other industries.
Exposure to soil and related dust lead is widespread in many inner city areas. Up to 20-40% of urban children in some neighbourhoods have blood lead levels equal to or above 5 micrograms per decilitre, the reference level of health concern by the U.S. Centers for Disease Control and Prevention (CDC) since 2012, and of the Australian National Health and Medical Research Council (NHMRC) since 2015.
2013 VAP Entry. Title: Backyard vegies. Lead-Safety Message: These backyard vegies are organic and lead-free. Are yours? Materials: Photo. Artist/Photographer: Gabriel Anderson. http://volcanoartprize.com/portfolio-item/these-backyard-vegies-are-organic-and-lead-free-are-yours/
Given the widespread nature of lead contamination in urban soils, exposure has proved challenging to reduce. In order to prevent this exposure, an evidence-based approach is required to isolate or remediate the soils and prevent children and adult’s ongoing exposure.
To date, the majority of community soil lead remediation efforts have been focused in mining towns or in discrete neighbourhoods where lead smelters have impacted communities. These efforts have usually entailed very expensive dig and dump soil lead remediation techniques, funded by the point source polluters.
Remediating widespread urban soil contamination using this approach is neither economical nor feasible from a practical standpoint. Despite the need to remediate/isolate urban soils in inner city areas, no deliberate, large scale, cost-effective lead remediation schemes have been implemented to isolate inner city soils impacted from lead sources other than mines and smelters. However, a growing body of literature of smaller scale pilot studies and programs does exist regarding low cost efforts to isolate lead contaminated urban soils.
Despite the widespread need for soil lead remediation in urban communities, there are relatively few peer reviewed studies in the literature that can serve as a base of evidence to evaluate the effectiveness of soil lead interventions.
In order to address this information gap, case studies from the literature regarding soil lead remediation were reviewed and have been posted under the heading "Solutions to the Problem: Review of the Soil Lead Remediation Literature" on the web page www.urbanleadpoisoning.com in the form of a table with links to the journal articles, including studies where children's blood lead levels were reduced by remediation of lead-contaminated home and preschool yard soil.
The table of “Solutions” is followed by a section titled: "Simple Non-toxic Way Forward" which lists the following four steps of Professor Howard Mielke's approach to managing lead-contaminated soil:
1.) Cut lawn as low as possible
2.) Lay down Bright Orange Geotextile
3.) Terraseeding (soil and seed mix) -0r- 3.) Apply Topsoil Using Topsoil Slinger &
4.) Hydroseed during Spring
Topsoil Slinger Video # 1
Topsoil Slinger Video # 2
Topsoil Slinger Video # 3
Topsoil Slinger Video # 4
Terraseeding (mix soil and grass seed)
Hydroseeder Video # 1
In case you didn’t check out those video links (above) yet, according to Geoscape Contracting in Ontario, Canada: “Terraseeding is an innovative and proven method of seeding large areas by automatically mixing composted soil with seed and applying it to the landscape with the use of a Terraseeding blower truck.” See www.geoscapecontracting.com
A "slinger" is a machine for spreading clean topsoil evenly and Hydroseeding is a planting process that uses a slurry of seed and mulch.
Hydroseeding being carried out at the Isle of Grain, Kent, UK. https://en.wikipedia.org/wiki/Hydroseeding
This information is being presented in order to inform scientists and the public that there are solutions to the urban soil lead contamination problem.