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Does all pollution require decontamination?

If an exploratory soil test discovers pollutants, this does not necessarily mean that decontamination will be required. In certain circumstances, given reasonable justification, pollution may be considered to be naturally present.

A research site in Ypres includes a coal depot and petrol station. The owner wants to sell the land.

A study of the site’s past revealed that artificial fertilizers had also been stored there in the past. The storage of coal and petrol, distribution hoses and the previous storage of artificial fertilizers are subject to obligatory studies.

Consequently a first soil investigation was required. Soil samples were taken by means of bores in the solid part of the ground. To check the quality of the ground water, monitoring wells were installed. After one week, samples were taken from the monitoring wells. Both the soil and the ground water were analysed for suspicious substances.

Slightly higher concentrations of PAHs (polyaromatic hydrocarbons) were found in the solid ground all over the site (including benzo(a)pyrene). According to OVAM standard procedure, the “Methodology for determining clear indications of serious soil pollution” was required in order to find out whether clear indications of a serious threat were present. This methodology revealed that no descriptive soil test is required for higher concentrations of PAHs.

Increased conductivity was found in the ground water. In theory a descriptive soil test is required. However, an extra ion balance carried out on the ground water brought the cause of the increased conductivity to light: increased levels of nitrites and ammonium were found.

The concentrations measured were compared with available analysis results for nitrite and ammonium in the area. This allowed us to conclude that increased concentrations were found across the region, perhaps due to farming activities in the area.

On the basis of strong argumentation discussing the source, cause and consequences, no descriptive soil test was required.

The exploratory soil test was sent to OVAM. OVAM has since approved the report and provided the soil certificate. The sale of the land went through at the agreed time.