Ecosystem Assessments
Westlakes Scientific Consulting has a long track record of undertaking ecosystem assessments, identifying exposed species and quantifying radiological doses for customers within the nuclear sector. WSC has a unique multidisciplinary capability to determine doses to biota from planned or unplanned discharges, or from radionuclides in the environment, prospectively and retrospectively, using either monitored or modelled environmental concentrations in air, water or land. We can relate doses to biota to the relevant legislative framework, benefiting from our close relationship with international expert advisory bodies. This puts us in a good position to deliver ecosystem assessment services with a research quality edge for our customers.
WSC work has included:
- Natura 2000 and environment discharge assessments to biota for Sellafield Ltd
- Assessments of repositories for NIREX
- Assessments of aerial radionuclides for AWE Aldermaston and the EA, among others, using the R&D 128 and ERICA methodologies.
- Intercomparisons of the ERICA and R&D 128 approaches with international methodologies (EPIC DOSES-3D, EDEN and RESRAD-BIOTA) with the IAEA and the ICRP.
Air Dispersion Modelling and Prediction
For the prediction of dispersion we have a complete suite of models for the prediction of transport of radionuclides including MEAD, MARISA, POSIDEON (long term assessments) and MIKE21 (short term assessments - accidental discharge simulations).
For aerial dispersion WSC uses PC-Cream, AERMOD, ADMS and EAS, whilst for terrestrial modelling we use ModFlow, FeFlow and MONDRIAN. In addition the MEAD model has been combined with the FASSET methodology to make realistic assessments of the impact on biota from Sellafield discharges.
We apply tools such as ERICA, EA R&D 128, RESRAD-BIOTA or our own bespoke VB-coded Excel spreadsheet models for radionuclides such as argon and krypton to predict doses using predicted or field-measured concentrations as an input. We can also estimate the effects of these doses by using databases such as FREDERICA. In certain cases we have coupled directly a dispersion model with doses-to-biota calculation methodology. For example, the MEAD model has been combined with the FASSET approach as a single software package to make realistic assessments of the impact on biota from Sellafield discharges.
Marine Modelling
WSC uses suitably calibrated and validated marine models, such as MARISA and MEAD, combining environmental monitoring data collected from the field, to calculate an input of environment radioactivity concentration for our ecosystem assessment models. Our dose to biota dynamic models for 99Tc and 129I in lobsters and winkles are fully validated with a combination of environmental monitoring data and laboratory data generated by ourselves in tracer experiments performed in laboratory (tank) conditions. In this way we have undertaken comparison of field and laboratory data in order to improve the quality of parameters for modelling.
We have experience in using the ERICA tiered approach for identifying most exposed species in an assessment. Our other assessment methods have also been used by us to conduct screening assessments, identifying most exposed species as candidates for more detailed assessment.
Development Expertise and Collaborations
A key WSC strength is the development of new methodologies for the assessment of doses to ecosystems. WSC has developed in collaboration with Liverpool University the EA R&D 128 assessment tool, with extensions for Ar and Kr. In preparation for RSA Stage 3 assessments we produced for the EA a new method for species not covered by R&D 128. We have improved the EA methodology for radon in biota and we are working with the ICRP to develop this approach for plants. WSC participated in the development of the FASSET methodology and in the ERICA project (aquatic model development and assessment tool testing). For Sellafield Ltd. and the NDA, WSC have developed and published time-dependent (non-equilibrium) models to predict doses to biota using a kinetic-allometric approach. We are involved in the EMRAS Biota Working Group, and we have had staff invited as experts to the EC PROTECT project and ICRP Task Groups dedicated to develop dosimetry for reference animals and plants, as part of an international effort to develop the radiological protection system for the environment.
Ecosystem assessment approaches need to be validated with experimental studies in areas where significant gaps in published data exist. We have performed experimental tank studies on aquatic biota for the development of models for predicting the uptake of 99Tc and 129I by periwinkles and lobsters. We have performed field measurements of biota to support calibration of validation of models, such as Pu and Po plankton measurements, not only for model validation but for comparison with laboratory experiments, in order to make transfer databases for aquatic organisms more robust.
Contact
For more information about ecosystem assessments or to discuss how we could provide you with the ecosystem assessment services you need, please contact: biokinetic.modelling@westlakes.ac.uk
Alternatively, please contact the Environmental Science Administration Office: esadm@westlakes.ac.uk (Tel: 01946 514094).
