Management Options for Contaminated Urban Soils to Reduce Public Exposure and Maintain Soil Health

Abstract

Soil management in urban areas faces dual challenges of reducing public exposure to soil contaminants, such as lead (Pb) and polycyclic aromatic hydrocarbons, and maintaining soil function. This study evaluated three management options for an urban lot in Cleveland, OH, containing 185 to 5197 mg Pb kg and 0.28 to 5.50 mg benzo(a)pyrene kg. Treatment options included: (i) cap the site with a soil blend containing compost and beneficially reused dredged sediments, (ii) mix compost with the soil, and (iii) mix compost and sediments with the soil. The soil blend cap reduced surface soil Pb to 12.4 mg Pb kg and benzo(a)pyrene content to 0.99 ± 0.41 mg kg. Aggregate stability for 2- to 0.25-mm aggregates in the soil blend cap was 13% compared with the 38% aggregate stability in the urban soil. Mixing compost with the soil reduced benzo(a)pyrene content, but sample variability indicated that elevated spots likely remained exposed at the surface. Compost addition diluted soil Pb and increased aggregate stability to 60%. Mixing compost and sediments with the soil was the only management option accomplishing both management goals of reducing surface soil contaminants and maintaining soil health. For this combined mixing option, aggregate stability was 37%, soil Pb was 15 mg kg, and benzo(a)pyrene was 0.99 ± 0.09 mg kg. Food-grade oil addition did not increase benzo(a)pyrene degradation. Future studies should evaluate how incorporating soil blends in different soil types with a range of contaminants may offer a suitable long-term management option for urban soil contaminants.

Benzo[a]pyrene—Environmental Occurrence, Human Exposure, and Mechanisms of Toxicity

“…The concentration of B[ a ]P was from 0.3 to 0.9 mg/kg of soil. B[ a ]P was also found in the concentration range from 0.28 to 5.50 mg/kg in municipal soil in Cleveland [ 45 ]. In another study, B[ a ]P was determined to be in a mean value of 2.31 ± 1.13 μg/kg in soil from greenhouse crops in the Antalya Aksu region in Turkey [ 46 ] ( Table 3 ).…”

Urban soil and human health: a review

“…Remediation of contaminated sites in urban environments should consider combining risk mitigation with the creation of green spaces. For example, Obrycki et al (2017) evaluated three management options for an urban site contaminated with Pb and PAHs. They found that the soil capping placed over the site reduced surface soil Pb from up to 5149 to 12.4 mg Pb kg −1 and benzo(a) pyrene content from up to 5.50 to 0.99 ± 0.41 mg kg −1 , which reduced human exposure to these contaminants markedly.…”

Potentially Toxic Elements’ Contamination of Soils Affected by Mining Activities in the Portuguese Sector of the Iberian Pyrite Belt and Optional Remediation Actions: A Review

“…These mine wastes are a continuous source of environmental contamination, mainly AMD, which arises from the oxidation of the sulfide wastes, a process which is well-known and has been thoroughly described [14,[34][35][36][37]. Remediation of mine-degraded sites is imperative to reduce the potential risks to the surrounding ecosystems and, consequently, to humans, and a source of continuous AMD formation [109][110][111]. Consequently, these mine waste deposits should be removed and/or controlled.…”