An integrated transient Tier-3 human health risk assessment framework based on multispecies reactive transport modelling
Year: 2026
Type: article
Abstract: Tier-3 human health risk assessments for groundwater contamination typically rely on numerical models with time-invariant parameters. However, when physical and biochemical properties evolve in time, parameters must be dynamically updated, but no integrated tool with this capability has been presented so far. To fill this gap, a tool called TRANSRISKRT3D was developed to incorporate time-varying first-order reaction rates into the multispecies reactive transport model RT3D for transient Tier-3 analysis. We applied it to an alluvial aquifer contaminated by chlorinated solvents. Initially managed with pump-and-treat, the site later transitioned to sequential in-situ bioremediation, significantly enhancing contaminant removal in certain areas. Considering volatile organic compounds inhalation risk over a defined exposure period, TRANSRISKRT3D captured how evolving remediation strategies influence spatio-temporal risk dynamics. Scenario analyses showed that early implementation of in-situ bioremediation would have halved the area with “unacceptable” risk levels ( R > 10⁻⁴), underlining the importance of timing in remediation planning. • TRANSRISKRT3D models dynamic, site-specific risk over space and time. • Time-varying reaction rates enhance the accuracy of Tier 3 groundwater HHRA. • Spatio-temporal risk maps support decision-making, optimize remediation actions. • Tested in a polluted aquifer transitioning from P&T to sequential bioremediation. • Early ISB implementation would have halved the area with unacceptable risk levels.
Source: Journal of Hazardous Materials
Authors: Daniele Pedretti, Marco Masetti, Lucia Cavalca
Institution: University of Milan
Language: English
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,340
OpenAlex ID: W7135062292