remediation system

Brownfields/Remediation: Alternative Cleanup Target Levels: A Powerful Development Tool for Contaminated Properties

March 30, 2021

 

Thanks to South Florida’s hot real estate market and impressive growth rates, a dwindling supply of properties are available for development in the area. The Atlantic Ocean limits South Florida’s development options to the east and Florida Everglades to the west. Due to these supply limitations, developers seek to redevelop contaminated landfills, golf courses, and agricultural land. Environmental due diligence is essential to the successful redevelopment of these types of properties. Depending on the property’s size and the extent of the contamination, redeveloping contaminated properties can cost upwards of a million dollars.

Typically, developers will have to deal with contaminants like ammonia at a landfill redevelopment project, arsenic at a golf course redevelopment project, or pesticides at agricultural redevelopment projects. In some cases, remediation and assessment using the standard or “default” cleanup target level (CTL) can stop a project from proceeding. However, before abandoning the project, developers should consider the potential for establishing alternative cleanup target levels (ACTLs) for the site’s contaminants.

Several technical strategies are available to developers considering redeveloping contaminated properties to reduce overall costs and expedite the construction schedule. Costs associated with managing material above a default CTL can include disposal of contaminated material, importing clean fill, and delays to permitting and construction schedules if an environmental regulator determines your assessment is incomplete.

 

Understanding Default Cleanup Target Levels

Environmental regulators use a range of tools to develop default CTLs. Default CTLs can be based on complex equations that consider toxicity and exposure assumptions such as ingestion rates, body weight, age, and exposure levels. Soil properties are also considered. In some cases, human health may not even be the determining factor in calculating a default CTL. Rather, a particular contaminant’s environmental impact on the local ecosystem may be what determines its default CTL.

While default CTLs are useful tools to formulate remediation strategies on a broad range of sites, default CTL values will be overly conservative for other sites. More explicitly, some sites’ present and future use and exposure characteristics are so different from the assumptions used to calculate the default CTLs – that the default CTL does not accurately correspond to the risk associated with the proposed sites’ use. In such cases, explore the development of an alternative cleanup target level (ACTL).

 

Establishing Alternative Cleanup Target Levels

With the right approach, a site ACTL could provide significant cost savings while maintaining regulatory compliance. But buyers beware; choose your environmental consultant carefully. The consultant should understand the site-specific factors that affect the calculation of the ACTLs. Often, a knowledgeable consultant has a good idea of the outcome even before investing the client’s time and money pursuing the alternative.

 

Cost and Schedule Benefits

To illustrate cost and development time-savings, consider a simple example of arsenic-contaminated soil at a residential development. Suppose there are no other reuse options available for the contaminated material, and the material must be disposed of at a landfill. Given 100,000 cubic yards (cy) of contaminated material at a disposal cost of $60 per cy, we estimate 6 million dollars in disposal costs, not including importing clean fill. However, if the site is an age-restricted residential community, certain exposure assumptions could be modified to calculate a much higher ACTL for arsenic. The soil would no longer be regulated as contaminated, and costs associated with disposal, imported material, and soil tracking are eliminated. Soil that was considered contaminated based on the default CTL is now clean based on the ACTL.

Let us look at a more complex example. Consider the case of a site contaminated with dieldrin, a common pesticide found at golf courses and agricultural properties. A leachability ACTL recalculates the default leachability of a particular soil contaminant. A leachability ACTL uses site-specific soil chemical and physical properties, such as soil organic matter content, bulk density, and annual average soil moisture content, and determines a more realistic risk profile associated with soil that could potentially leach contaminants into the groundwater. With an ACTL above the default CTL, remediation may not be necessary, or the site may not require a deed restriction, or ongoing costs associated with monitoring of the groundwater or operation of a remediation system could be eliminated, making the completed project more attractive to potential buyers.

 

Summary

Developing ACTLs is a careful, thoughtful strategy that an experienced environmental consultant can propose based on the site’s unique conditions. The developer’s financial objectives and schedule and the property end-use must be carefully considered to develop a thorough redevelopment approach. The use of an ASCTL could mean the difference between a project that is financially infeasible and one that is attractive and profitable.

 

Learn more about remediation and brownfields redevelopment.

 

About the Author: Troy Schick, PE, specializes in stormwater and groundwater management and voluntary remediation of properties, including brownfields and former landfills. Troy uses his experience at SCS Engineers and education as an Environmental Engineer and Environmental Manager with field inspection, sample collection, documentation, and project management to benefit Florida communities. Troy is available for consultation at tschick@scsengineers.

 

 

 

 

 

 

Posted by Diane Samuels at 6:00 am