Abstract

Thermally cleaned soil (TCS) was used for the construction of Perkpolder’s dike. TCS contains substances such as metals and salts that could spread to the groundwater and surface water next to the dike. For the second time now the National Institute for Public Health and the Environment (RIVM) has carried out a study to ascertain whether these substances are present in the vicinity of the dike and what possible effects this could have on health and the environment. The study was prompted by the fact that more measurement data has become available on the concentrations of the substances in the soil, groundwater and surface water. In addition to this, local residents have asked questions on the effects on their health and the environment.

The study reveals that contamination from the TCS does not pose any risks to local residents’ health. The substances are sometimes already naturally present or the concentrations found are too low to have any effects. The TCS has not influenced the soil quality of the vegetable gardens. Moreover, it is safe to walk on the embankment and swim in the surface water, even though it is not intended to be swimming water. The fresh groundwater examined, the strips of farmland and the topsoil on the dike are suitable for watering plants and for cows to drink and graze. They are also suitable for arable farming.

During the study, other substances that are most likely not to have come from TCS were found as well. These include PFAS, dioxins and arsenic. The PFAS in the surface water are very likely to have come from the Western Scheldt. It is possible that arsenic could come from the TCS, but in any case it is naturally present in high concentrations in the province of Zeeland. Due to the presence of the PFAS, arsenic and dioxins, RIVM would advise not eating fish that you have caught yourself in this area. RIVM also recommends that a study be conducted to establish whether PFAS are present in swimming water in the area and if so, what the effect of this will be.

The groundwater and surface water right next to the dike are naturally salty, so using this water for farming is not recommended. For the same reason, and because of the presence of arsenic and PFAS, dogs should be discouraged from drinking from the surface water. It is unknown exactly how harmful the arsenic and PFAS in the surface water will be to dogs. The chances of direct effects due to the salt will be the decisive factor in any risks to dogs if they do drink from the surface water.

Lastly, RIVM studied what effects the proposed measures for the dike will have on health and the environment. If any excavation work were to be performed on the dike, then RIVM would advise minimising the release of dust. The effects of the other measures are expected to be limited, even if there is not yet certainty on the maximum quantity of metals that could be released.