SEVESO III requires an assessment of the possible impact of a major accident at a facility on the receiving environment. To demonstrate the scope of work required for a hydrogeological assessment a case study of a recently completed project at the Tüpraş oil refinery site in Turkey was presented by Teri Hayes (Director - AWN) at the April 2016 International Association of Hydrogeologists Irish Group's annual conference in Tullamore, Co. Offaly.

The three primary objectives of the project involved establishing a 'workable' Conceptual Site Model (CSM) for the oil refinery, characterising the resultant potential pollutant linkage to the water environment and developing a calibrated groundwater model. The resulting data would indicate the requisite steps to be taken to ensure SEVESO compliance.

The various stages of the project included:

1. Identification and quantification of dangerous substances potentially present at the facility

2. Evaluation of the hazards present for SEVESO assessment - requiring an understanding of storage, operating and foreseeable accident conditions

3. Identification of aquifer (pathway) characteristics – examining regional hydrogeology

4. Determination of site specific aquifer pathway characteristics - conducting site investigations to obtain site specific data

5. Identification of pollutant linkages and pathways

6. Identification of site-related environmental receptors

7. Consequence modelling – of groundwater, human receptors and risk assessment

8. Assessment of Major Accidents to the Environment (explanation of MATTE assessment) - including potential impacts on groundwater, surface water as drinking water and likely duration of harm.

It was concluded that understanding the conceptual site model (Source – Pathway - Receptor) is key to determining the detail required in undertaking a SEVESO hydrogeological assessment and risk model. 

Teri Hayes' presentation at IAH 2016 may be viewed by accessing the file below.

If you have any queries on hydrogeology in SEVESO III or IED licensing please contact Teri.Hayes@awnconsulting.com