Background

It concerns a site of a chemical plant (since 19th century), which is situated alongside the Scheldt. The plant has formerly been used for the production of tar & tar oil products. These former activities lead to a complex contamination in soil and groundwater with tar (naphthalene), oil, BTEX, creosotes, phthalates and phenols in the quaternary layer (0 – 13 m bgl).

Challenge

What is the mobility of the contamination? What is the spreading risk towards the Scheldt river? What is the total mass discharge towards the Scheldt? The tidal of effect of the Scheldt river is an extra challenge in this project.

Our solution

We measured BTEX and naphthalene mass fluxes in 5 monitoring well locations at different depths. A total of 30 iFLUX cartridges have been submerged for 6 weeks in the subsoil and analysed. In parallel, a theoretical determination of the naphthalene mass flux was also performed by Arcadis based on estimated Darcy water flow velocities and naphthalene concentrations derived from detailed UV-ROST and HPT probing.

Image CVOC mass discharge of chemical site towards Scheldt river Image 1
Image CVOC mass discharge of chemical site towards Scheldt river Image 2
Image CVOC mass discharge of chemical site towards Scheldt river Image 3
Image CVOC mass discharge of chemical site towards Scheldt river Image 4
Image CVOC mass discharge of chemical site towards Scheldt river Image 5
Image CVOC mass discharge of chemical site towards Scheldt river Image 6