What do the data show? Knowledge map development for comprehensive environmental assessment

Environmental and human health risk assessments benefit from using data that cross multiple scientific domains. Although individual data points may often be readily understood, the total picture can be difficult to envision. This is especially true with gaps in the data (e.g., with emerging substances such as engineered nanomaterials [ENM]), such that simply presenting only known information can result in a skewed picture. This study describes a method for building knowledge maps (KM) to visually summarize factors relevant to risk assessment in a relatively easy to interpret format. The KMs were created in the context of the comprehensive environmental assessment (CEA) approach for research planning and risk management of environmental contaminants. Recent applications of CEA to emerging substances such as engineered nanomaterials that have numerous data gaps have suggested that a more visually based depiction of information would improve the approach. We developed KM templates as a pilot project, to represent pertinent aspects of conceptual domains, and to highlight gaps in available information for one particular portion of a specific CEA application: the comparison of environmental transport, transformation, and fate of multiwalled carbon nanotubes (MWCNTs) and decabromodiphenyl ether as flame retardants. The results are 3 KM templates representing Physical Properties, Transport, and Transformation. The 3 templates were applied to both substances, resulting in a total of 6 KMs. In addition to presenting the KMs, this paper details the process used to generate them, to aid KM development for other sections of CEA applied to MWCNTs, or to apply the process to new CEA applications.