Ordinance
on the Remediation of Polluted Sites
(Contaminated Sites Ordinance, CSO)

^{1 Sub­ject to para­graph 1bis,} a pol­luted site is deemed to be in need of mon­it­or­ing to pro­tect the sur­face wa­ters, if:⁹

a.

any of the con­cen­tra­tion val­ues spe­cified in An­nex 1 is ex­ceeded in the elu­ate of the ma­ter­i­al at the site which is sus­cept­ible of af­fect­ing sur­face wa­ters; or

b.

in wa­ter that flows in­to sur­face wa­ters, a con­cen­tra­tion value spe­cified in An­nex 1 is ex­ceeded for sub­stances ori­gin­at­ing from the site.

^{1bis If after sev­er­al years of mon­it­or­ing a site, it is es­tab­lished that, con­sid­er­ing the evolution of pol­lut­ant con­cen­tra­tions and the char­ac­ter­ist­ics of the site, it is highly prob­able that the site will not need re­medi­ation un­der para­graph 2, the site is deemed no longer to be in need of mon­it­or­ing.10}

² For the pro­tec­tion of sur­face wa­ters, a pol­luted site is deemed to be in need of re­medi­ation if:

a.

in wa­ter that flows in­to sur­face wa­ters, the con­cen­tra­tion of sub­stances ori­gin­at­ing from the site ex­ceeds by ten­fold a con­cen­tra­tion value spe­cified in An­nex 1; or

b.

it is in need of mon­it­or­ing in ac­cord­ance with para­graph 1 let­ter a, and ow­ing to in­suf­fi­cient re­ten­tion ca­pa­city, or de­grad­a­tion of sub­stances ori­gin­at­ing at the site, there is a real danger of pol­lu­tion of sur­face wa­ters.