Orientation and characterisation study of contaminated soils

Orientation and characterization studies of polluted soils

In order to determine the presence of pollutants in the soil and to establish the Content and concentration, it is required to conduct studies and analyses according to a methodology established by the regional authority. It's about The orientation study And of The characterization study polluted soils.

In the context of a land development project, one of the first steps to take in order to obtain a permit is to conduct a policy study. This is often directly associated with a characterization study. We then speak of a combined study.

“This orientation study aims to determine whether the soil on which the project is envisaged is polluted or not and, if so, to identify the nature of the pollution and to provide a valuation Of its magnitude, explain Béatrice Lefebvre, Project Engineer atABV Development, certified soil management consultancy. This first field approach, according to the established conclusions, makes it possible to justify whether a pollution characterization study and a risk study should be carried out.”

How is a soil orientation study conducted?

The policy study should be conducted using a methodological approach determined by the administration. The orientation study includes a preliminary study phase, a phase of investigation of suspicious areas and an interpretation phase.

“In the preliminary study, the aim is to gather all the data relating to the plot in question, and in particular to carry out a historical study of the land and to make an initial visit to him, details Béatrice Lefebvre. The investigation also involves carrying out an initial analysis of samples taken from the ground or groundwater in suspicious areas, to verify the presence or absence of pollution. This study concludes with a report, summarizing the results of the analysis and comparing them with current standards in order to draw up a set of conclusions and recommendations.”

From the soil orientation study to the characterization study

The report may conclude that a characterization study is required.

“It is then a question of deepening the analyses, in order to determine more precisely the nature of the pollution, to delimit it and to map it., continues the expert. If it is a pollution stain, for example, it is necessary to be able to establish its volume, in other words its extent and depth, by carrying out successive drilling and analyses to determine the concentrations of pollution in various locations. If it is an embankment pollution, the characterization involves more a statistical approach according to the perimeter of project.”

If it's about characterize pollution in groundwater, the analysis is carried out using a piezometer. It is a tube that allows access to groundwater from the surface.

The characterization study also includes an overall assessment of the threat or risks.

Why should an orientation and characterization study be carried out?

Studies on the orientation and characterization of soil pollution will in particular be useful for conducting therisk study and, if necessary, determine whether or not it is appropriate to carry out a sanitation project .

“For example, if we find the presence of historical pollution, in other words prior to April 30, 2007, and that it does not present a risk for human health, for groundwater and the surrounding ecosystem, there is no need to clean up. If the pollution is considered to be new, it is always necessary to carry out a sanitation ”, explains Beatrice Lefebvre.

Also read — Project to clean up soil and groundwater in the Walloon region

Why should a combined study be preferred directly?

To save time, it is often more interesting to conduct a combined study directly, especially if there is a significant suspicion of pollution.

“In fact, the administration has 30 days to validate an orientation study, which will conclude whether or not it is necessary to carry out a characterization study. For this one, the validation period is 60 days, explain Béatrice Lefebvre. If we conduct the two studies together, we not only Saves time at the level of field analyses, but the validation period is limited to 60 days.”