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

¹ Sub­ject to para­graph 1^bis, a pol­luted site is deemed to be in need of mon­it­or­ing to pro­tect the ground­wa­ter, if:

a.

any of the con­cen­tra­tion val­ues spe­cified in An­nex 1 is ex­ceeded in the elu­ate of the ma­ter­i­al at the site;

b.

for ground­wa­ter wa­ter pro­tec­tion areas A_u, the con­cen­tra­tion of sub­stances ori­gin­at­ing from the site im­me­di­ately down­stream of the site ex­ceeds 10 % of one of the con­cen­tra­tion val­ues spe­cified in An­nex 1;

c.

for ground­wa­ter out­side wa­ter pro­tec­tion areas A_u, the con­cen­tra­tion of sub­stances ori­gin­at­ing from the site im­me­di­ately down­stream of the site ex­ceeds 40 % of one of the con­cen­tra­tion val­ues spe­cified in An­nex 1.³

^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.⁴

² A pol­luted site is deemed to be in need of re­medi­ation to pro­tect the ground­wa­ter, if:

a.⁵

po­ten­tial wa­ter pol­lut­ants ori­gin­at­ing from the site are de­tec­ted in ground­wa­ter catch­ments of pub­lic in­terest in con­cen­tra­tions that ex­ceed the de­tec­tion threshold;

b.⁶

for ground­wa­ter in wa­ter pro­tec­tion areas A_u⁷: the con­cen­tra­tion of sub­stances ori­gin­at­ing from the site im­me­di­ately down­stream of the site ex­ceeds one-half the con­cen­tra­tion value spe­cified in An­nex 1;

c.⁸

for ground­wa­ter out­side wa­ter pro­tec­tion area A_u s: the con­cen­tra­tion of sub­stances ori­gin­at­ing from the site im­me­di­ately down­stream of the site ex­ceeds double the con­cen­tra­tion value spe­cified in An­nex 1; or

d.

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