Review of Screening Risk Assessment Methods for Nanomaterials

Report, 2016

Nanomaterials are a new and growing type of material, and concerns have been raised regarding their potential risks to human health and to the environment. These concerns have spurred the development of risk assessment methods with the purpose of assessing risks related to nanomaterials. However, such developments have proven to be challenging, both with regard to assessing toxic effects of nanomaterials and to predicting human and environmental exposure to nanomaterials. In response to these challenges, a number of screening risk assessment methods for nanomaterials have been developed. In contrast to full risk assessments, screening risk assessments typically assess risk in a qualitative manner, for example on an ordinal scale from 1 to 3. The aim of this report is to investigate existing screening risk assessment methods for nanomaterials and provide recommendations on their further development. In order to fulfil this aim, a background section about three general and often-used screening risk assessment approaches is first provided. Second, screening risk assessment methods developed specifically for nanomaterials are reviewed.Third, recommendations on potentially beneficial developments within the field are provided in a concluding discussion. The review showed that many quite different screening risk assessment methods for nanomaterials exist. A total of 20 were identified: ANSES, CB Nanotool 2.0, early warning signs, Genaidy’s method, Groso’s method, Guidance, Hierarchical Rank Aggregation, LICARA nanoSCAN, Nano-Evaluris, NanoHAZ, NANoREG, NanoRiskCat, NanoSafer, Occupational Hazard Band for Nano, Precautionary Matrix, Relative Risk Analysis, Risk Trigger Scores, Stoffenmanager Nano, TEARR, and the WCD model. These methods share many features, such as the scoring and ranking of risk on ordinal scales. However, they are also different in several respects. The exact scales used in the different methods differ, and, more importantly, they vary concerning the complexity of the scoring and ranking procedure, and which hazard input parameters are used in order to conduct the scoring and ranking. Some methods are relatively simple and require few hazard input parameters, while others are more complex, and require many input parameters, some of which are difficult to determine. It was also noted that most methods focused on occupational human health risks, while fewer focused on environmental risks. Based on the review, we propose three main recommendations. First, the further development of screening risk assessment methods focusing on environmental risks is warranted. Second, modest complexity and input data requirements are beneficial for the applicability of the method and more in line with the spirit of screening risk assessment. Third, since ordinal scales have problems related to mathematical operations and scale compression, we recommend they be used with caution.