Best Practices for Development and Use of Data Screening Values and Clean-up Objectives

Oral Presentation

Prepared by C. Hiegel
Trihydro, 1252 Commerce Dr. , Laramie, WY, 82072, United States

Contact Information:; 307-745-4993


Environmental professionals face many challenges when developing and negotiating screening objectives or clean-up objectives (objectives), developing their planning documents, coordinating with the laboratory to meet the objectives, and then comparing their data to the objective. Laboratories also face challenges, including meeting these objectives and then communicating when the expectations of their client (environmental professional, responsible party, regulatory body) were not met.

The Environmental Protection Agency (EPA) programs, state regulatory agencies, and other regulatory bodies provide objectives that are used to determine if a contaminated site is considered clean, compliant, can be closed environmentally, and/or can be provided with a no further action (NFA) determination. These objectives are developed using toxicological studies conducted by research organizations to determine at what level human, plants, and animals (receptors) are affected by specific toxins and what risks are posed to those receptors.

These published objectives are typically based on risk to human health, and include exposure time, frequency, age and body weight, and potency or ability to cause cancer. They also can include the chemical’s potential to migrate in the groundwater or from the soils to the groundwater based on the individual characteristics. However, ecological receptors can also be used to develop objectives, depending on the site location. Ecological receptors are more complex and can be different for each type of plant, animal, or invertebrate. Responsible parties and regulatory bodies then determine which standards to use through simply pulling them from a table, using a multitude of hierarchy sources, and/or calculating site-specific objectives.

Each of these objectives is based on toxicological studies conducted in the controlled environments of a laboratory. The use of realistic samples (soils, groundwater, sediments, and ecological media) and instrumentation and will present challenges to the environmental laboratory in meeting the risk-based objectives for the data. Therefore, expectations of what detection limits are realistically feasible in the laboratory must be communicated to all parties at the beginning of the project. This presentation will discuss best practices for developing screening levels, how to set expectations and plan for what the data will realistically look like, what coordination steps are necessary between the environmental professional and the laboratory, and how to compare the final results to the objectives.