Evaluation of the environmental risk of defence-related chemical compounds using a toxicity scale approach

Environmental Risk Assessment evaluation is commonly used to estimate the likelihood, and magnitude of the environmental effects associated with a particular anthropogenic activity. Typically, environmental risk assessment procedures rely on the use of quantitative data to determine the impact of different substances, although minimal information is available regarding contamination risks associated with the soil environment. Here a methodology has been developed by combining the guidelines from the ECHA and the USEPA for Predicted Non effect Concentration (PNEC) and Ecological Soil Screening Levels (Eco-SSL) to produce a novel toxicity scale. This was demostrated with five defence-related chemicals, 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), Cypermethrin, Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS), to provide high, medium and low risk levels in soil. This means, detected soil contaminant concentrations in the low risk level are unlikely to require immediate remediation but may need to be monitored. Whereas, contaminant concentrations in the medium and high risk level are likely to require remediation. Therefore, the developed toxicity scale will support the assessment of the chemical impact of defence-related chemicals on the environment to avoid severe soil contamination and reduce the likelihood of high remediation costs.