Evaluating Emerging Contaminant Risk Levels at Redevelopment Sites

Emerging contaminants can pose significant challenges for brownfield and redevelopment site property managers and developers.  Without firm regulatory standards for guidance, it can be difficult to know how to manage risks associated with possible contamination at a site.  To address liability concerns and define a clear path forward, property managers and developers can use decision analysis tools in concert with up-to-date information to evaluate their redevelopment site’s risk level. 

Let’s Back Up a Second…What Defines an Emerging Contaminant?
Emerging contaminants are synthetic or naturally occurring chemicals that are not commonly monitored or regulated in the environment, but have the potential to enter the environment and cause adverse ecological and/or human health effects.  They are widely present but there is often considerable uncertainty regarding their management in terms of risk, regulatory compliance, analytical techniques, and remediation.  In decades past, compounds such as dichloro-diphenyl-trichloroethane (DDT) and methyl tertiary-butyl ether(MTBE) have been considered emerging contaminants.  Currently, per- and polyfluoroalkyl substances (PFAS), 1,4-dioxane, and microplastics are generating attention as emerging contaminants.

Emerging Contaminants at Redevelopment Sites
Without regulatory screening standards and guidance, brownfield and redevelopment site property managers and developers experience challenges with addressing emerging contaminants.  While the Environmental Protection Agency (EPA) and Interstate Technology and Regulatory Council (ITRC) provide guidance fact sheets for some emerging contaminants, without an existing regulatory standard for comparison, developers find themselves operating in a gray area.

To Sample or Not to Sample?
It may be a good idea to appraise a site for emerging contaminants to gain an understanding of possible risks and future challenges associated with redevelopment. 

An alternative is to wait until a future regulatory standard is developed; however, while waiting can equal more regulatory clarity and an informed course of action, the emerging contaminant may migrate to a larger area, resulting in more difficult and costly remediation.  Absent regulatory standards for emerging contaminants, property managers may consider assessing risk associated with a site based on financial liability.

Getting Started: Decision Analysis Tools
Developers should reference site-specific data, such as historical uses or site lithology and hydrology, when deciding whether to sample for emerging contaminants or acquire property.  Available literature can help assess a site’s risk based on historical use.  Additionally, case law may provide guidance on liability drivers within various jurisdictions.


Not sure where to start? Begin with this flowchart to see how site-specific data, in combination with other factors, may be used to evaluate emerging contaminant risk.


Best Practices for Addressing Emerging Contaminants

  • If emerging contaminants are indeed discovered at a site, it is important to consider additional background sampling to determine if there may be impacts from other sources unrelated to the site.
  • For purchasers of redevelopment sites, it is also important to consider American Society for Testing and Materials (ASTM) compliant Phase I Environmental Site Investigations. The revised E1527 standard anticipated for 2020 may include language that implies emerging contaminants can be considered “in scope” for compliance with regulation.
  • Consider seeking counsel regarding ways to limit liability.
  • Both buyers and sellers of properties may consider environmental insurance policies that cover impacts of emerging contaminants.
Allison Riffel
Allison Riffel, PE
Engineering Specialist, Golden, CO

Allison is a professional engineer with over 20 years of experience in site assessment, remediation, regulatory compliance and permitting. She specializes in remediation of chlorinated solvents, petroleum, and PCBs under RCRA, TSCA, CERCLA, and state voluntary cleanup programs with regulatory expertise in 11 states.

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