When should a soil pollution study be carried out?

The different types of studies possible for soil pollution

Soil pollution studies are carried out by soil pollution experts approved by the Walloon administration, such as ABV Development employees.

The orientation study

The aim of the orientation study is to determine whether pollution is present on a given terrain and, if so, to provide an initial description of the extent of this pollution.

The orientation study consists of several steps:

• The historical study: a documentary review will be carried out, including all the administrative and technical documents useful for collecting information on soil pollution. These may be environmental permits or old operating permits. For example, for a former industrial site, we need to know where the polluting activities were located before defining a drilling and soil analysis plan. This first phase consists in requesting the administrations as well as the project owner to obtain all the information relating to potentially polluting activities or installations (old and current) on the study site.
• Drilling campaigns: This step includes conducting surveys, taking soil samples and, where applicable, groundwater samples, and analyzing them in an approved laboratory. Various pollutants will be analyzed in the laboratory: mineral oils, heavy metals, chlorinated solvents, cyanides, PAHs... For each of these pollutants, the Soil Decree includes standards (so-called threshold values), i.e. the concentrations below which a soil is considered to be unpolluted. Beyond these standards, the land is qualified as polluted, and requires the carrying out of a characterization study.
• The policy study report: the content of this report is fixed by the Soil Decree; it is a compilation of information relating to the site, its environment (e.g. geological context), the history of activities, the state of the soil. The report can conclude that either the land is healthy, without pollution, and the administration can then issue a soil control certificate (administrative document that allows the obligations in terms of soil studies to be completed), or the relationship to the presence of pollution and in this case, a characterization study must be carried out.

The characterization study

If the orientation study report concludes that there is soil pollution, a characterization study must be carried out. This study includes carrying out additional surveys in order to delineate the pollution present (horizontal and vertical delimitation); the objective is to define the volumes of polluted soil. For so-called “historical” pollution, i.e. generated before 30 April 2007 (according to the Soil Decree), a risk study will be carried out and will make it possible to define whether the pollution presents a risk for human health, for the environment, or if it presents a risk of dispersion. If pollution presents a risk; the Soil Decree requires sanitation, preceded by a sanitation project. This is also the case for so-called “new” pollution, that is to say generated after April 30, 2007.

Either the land has historical pollution that does not generate risks, the pollution can remain in place, sometimes by implementing follow-up measures.

The sanitation project

A remediation project is a document describing the methods of managing or treating pollution on a site. In a sense, it is a specification for sanitation work.

The classic case of a sanitation project is the excavation of the land and the sending of the land to an authorized treatment center. The dig is then backfilled with healthy land.

There are also other techniques called “in situ”, that is, which do not require the excavation of soil, such as: injecting oxidant into the soil, pumping contaminated groundwater, etc.

In what cases should a soil study be carried out?

A soil study can be carried out on a voluntary basis, and submitted to the administration. This is article 22 of the Soil Decree.

The most frequent case is the carrying out of a soil study as part of a real estate development project. The remediation of certain polluted sites may be too expensive than for real estate development. This is why it is important to carry out a soil study beforehand, in order to precisely define the measures that will have to be implemented, their timing, and their cost.

However, in certain circumstances, it is mandatory to carry out a soil survey. These are “generating facts” of the orientation study:

Request for planning permission

The Walloon administration has set up a soil condition database (known as BDES). It is an application that offers access to all the data available to the Administration on the state of soils in Wallonia. The BDES defines 3 codes for cadastral parcels:

• The color lavender blue: This color indicates that the data available to the Administration is of a strictly indicative nature. This data does not generate an obligation to investigate or remediate the soil.
• The peach color: This color indicates that the plot has already been, or should still be, the subject of soil management procedures, and that particular attention should be paid to it.
• Transparent plot: If the parcel in question does not contain one of these two colors, it is considered “transparent” (no known information).

For land fishing under the BDES for which an urban planning permit involving work with land use, an orientation study must be carried out. The BDES fishing plots in fact consist of land where potentially polluting activities have taken place.

This study obligation is specified in article 23 of the Soil Decree.

Renewing an environmental permit

An orientation study is carried out by the operator of an activity or installation that presents a risk for the soil, in the event of cessation of activity, bankruptcy or at the end of the environmental permit. This is article 24 of the Soil Decree.

When an activity is installed on a site and is potentially polluting, a soil study must therefore be carried out each time a permit is renewed, i.e. every 20 years.

Environmental accident

A soil study must also be carried out in the event of environmental damage (accident, hydrocarbon spill, fire, etc.). This is article 25 of the Soil Decree.

At the request of the administration

Finally, an orientation study may be carried out at the decision of the Administration if it has information on the existence of soil pollution.

How does ABV Development make a difference?

• Specialization in the environment, security and land use planning sector
• Conducting studies with a vision: “Your project must succeed! ”
• Personalized support based on the quality of the customer relationship
• A team of experts who share values of ethics, deontology, integrity and transparency throughout their mission

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