Assessing the relevance of environmental exposure data sets

Environmental exposure data are used by decision-makers to assess environmental risks and implement actions to mitigate risks from contaminants. The first paper in this series summarized the available evaluation schemes for environmental exposure data, of which there are few compared to those available for environmental hazard data. The second paper covered the assessment of reliability of environmental exposure datasets under the Criteria for the Reporting and Evaluation of Exposure Data (CREED). The aim of this paper is to provide an overview and practical guidance on the relevance assessment in the context of the CREED approach for evaluating exposure monitoring datasets. Systematically considering relevance is critical for both evaluating existing datasets and for optimizing the design of new monitoring studies. Relevance is defined here as the degree of suitability or appropriateness of a dataset to address a specific purpose or to answer the questions that have been defined by the assessor or for those generating exposure data. The purpose definition will be the foundation for the relevance assessment, to clarify how the assessor should rate the assessment criteria (fully met, partly met, not met/inappropriate, not reported, not applicable). This will provide transparency for anyone reviewing the outcomes. An explicit gap analysis (i.e., an articulation of the dataset limitations for the stated purpose) is an important outcome of the relevance assessment. The relevance evaluation approach is demonstrated with three case studies, all relating to the freshwater aquatic environment, where the datasets are scored as relevant with or without restrictions, not relevant, or not assignable. The case studies represent both organic and inorganic constituents, and have different data characteristics (e.g., percentage of censored data, sampling frequencies, relation to supporting parameters).