Assessing RiskFeedback

Data Collection and Evaluation is primarily concerned with the acquisition of necessary data from environmental media to identify contaminants of potential concern (COPCs) and support the calculation of exposure point concentrations in the Exposure Assessment. Data may be acquired from samples of environmental media suspected of containing chemicals at a site, as well as from samples with chemical concentrations representative of background conditions. From these samples, conclusions are drawn about what chemicals are present in which media, and at what concentrations.

Data Collection and Evaluation relies heavily on the conceptual site model (CSM) to identify which environmental media should be sampled, and at which locations. The types of analyses performed on the environmental samples, including decisions on the analytical suites and necessary analytical sensitivities, are also based on the CSM. The CSM in turn is updated as additional data are collected and analyzed.

The EPA’s Data Quality Objectives Process for Hazardous Waste Sites is an application of EPA's broader data quality objectives (DQO) process that is specific to hazardous waste sites. The DQO process provides a tool for determining the type, quantity, and quality of environmental data necessary to support environmental decision making. As described by EPA, the DQO process involves a series of seven steps to develop qualitative and quantitative statements about the purpose, requirements, and constraints of data collection and evaluation. The first four steps in the process (State the Problem, Identify the Decision, Identify Inputs to the Decision, and Define the Study Boundaries) are broadly applicable to virtually all environmental investigations, while the latter steps are more specific to investigations where statistical tools are employed to guide data acquisition and decision making.

EPA's Data Quality Objectives Process for Hazardous Waste Sites, as well as other documents related to quality assurance in the collection and evaluation of environmental data, are available on the EPA's Quality Staff's web page at www.epa.gov/quality/.