Environmental exposure scenario for reagents used in in-vitro diagnostics

In-vitro diagnostic assays involve various substances that may be released into the environment via a sewage treatment plant if the effluent from diagnostic instruments is discharged into the drains. Because the release of liquid waste into the public sewer system is regulated at national and/or local levels, a risk assessment per site should be performed to determine whether the release of the effluent from in-vitro diagnostic equipment is compliant with applicable regulations. To facilitate the assessment, we developed a screening tool to generate exposure scenarios for chemical substances used in in-vitro diagnostic assays. This screening tool helps in determining a) whether release of the effluent into the sewer system would be allowed from a regulatory point of view and b) whether such release would result in potential risks to surface water. The screening tool is based on conditions encountered at typical usage sites in Switzerland and Germany, with the option to adapt them to other local settings. In addition, measured analytical results of liquid waste together with typical operational parameters of diagnostic equipment were defined as default input parameters. The resulting concentrations in liquid waste and predicted environmental concentrations (PEC) are compared with regulatory limit values for release into the sewer system and predicted no-effect concentrations (PNEC) for surface water for risk estimation. The functioning of the presented screening tool is demonstrated by two assessments performed for fictitious but typical hospitals in Switzerland and Germany. It identified substances that cause potential concern for which a more advanced assessment is required.