Overview of the exploratory drilling and level of contamination in the early stages of the remediation.
Published on 01/07/2021
Ugine Kuhlmann had been liquidated in 1996, and the official responsibility to actually remediate the site – a so-called orphan site – lay with the French government. Nonetheless, as the new owner of the site, Novartis committed to the investigation and remediation of the contaminants of concern although it was not the party responsible for polluting the site soil and groundwater.
Novartis already had an established program for monitoring and remediating production sites. The company had played an active role in remediating several chemical waste sites in the Basel region.
Project management
Novartis set up a project governance structure consisting of four levels:
– The Project Steering Committee, acting as external governance board of the project with key external stakeholders, such as members of the French and Swiss authorities. Its key role was to provide guiding decisions, based on the public environment and regulations.
– The Project Coordination, acting as internal governance and supervisory board of the project. Its key role was to provide strategic direction and supervision of the project activities. It decided on costs, schedule, scope and quality.
– The Project Core Team Committee, acting as operational decision board of the project. Its key role was to provide all the required operational decisions and to supervise and control costs, schedule, scope and quality.
– The Project Technical Committee, acting as technical decision board of the project. Its key role was to implement the technical solution and perform all the required technical decisions.
Initial investigations
Novartis based its proposed remediation work on site investigations done in the 1990s by the BRGM and Antea consultancies. Novartis was also able to tap information gathered by the French authorities, which had been monitoring the site since the construction of the wastewater treatment plant in 1974.
Novartis completed additional soil and groundwater investigations in 2011 and 2012 to define the extent of contamination and to guide development of remediation plans for review and approval by all authorities.
In 2011, 76 boreholes were drilled into the ground, sampling material from depths of 6 to 12 meters. Additionally, 10 trenches measuring 2 4 meters at a depth of 3 meters were excavated to check the feasibility of on-site treatment of the soil to reduce transportation impacts. In 2012, these samples were further analyzed for more chemicals, including dioxin and furan, to get a better understanding of the nature and extent of pollution on the site and associated risks. In order to ensure that the findings remained up to date, more than 300 additional exploratory boreholes were gradually needed in the course of the investigation and remediation work.
The investigations showed that HCH was widespread to a depth of 12 meters at concentrations ranging from 0 to 50,000 mg/kg. In one area on the site, virgin HCH was observed at a depth of 6 to 7 meters.
The entire area was divided into contaminated zones based on the concentration of HCH. In some zones, additional chemicals were detected, such as benzene, PCBs, dioxins and heavy hydrocarbons. However, no additional pesticides or anilines were detected, nor were any light hydrocarbons detected.
The groundwater concentrations of α- and γ-isomers were below the detection limits, but β- and δ-isomers were present at concentrations of 25 µg/liter and 110 µg/liter. These concentrations were very high considering that the maximum concentration of HCH discharged into the Rhine was set at 5 µg/liter.
The future use of the property was reviewed with the authorities to determine the maximum acceptable concentration of residual HCH that could remain in place and the associated future risks following site remediation. This comprehensive risk assessment and future land-use consideration also included other contaminants, such as chlorobenzenes, dioxins and furans. The purpose of this assessment was to define site-specific cleanup targets that would be reviewed and approved by the relevant authorities.
