33. At least 3 times a year, in the spring, summer and fall, the operator of a contaminated soil burial site must take a groundwater sample in each of the monitoring wells located on the perimeter of the facilities to quantify each of the substances detected in the leachates collected in the preceding sampling programs. If contaminants are detected, the operator must take a groundwater sample in each of the monitoring wells located at the limits of the land and have them analysed for the same contaminants.
During sampling, the piezometric level of the groundwater shall also be measured.