Q&A PFAS in the ground at Schiphol

We understand that local residents are worried about their health after hearing about PFAS-containing soil at Schiphol. There is no risk to health; we handle the PFAS-containing soil very carefully and follow all the rules. The National Institute for Public Health and the Environment (RIVM) has established human risk limits for PFOS and other PFAS. Research shows that there are no indications that PFAS contamination on Schiphol grounds has caused increased levels of PFAS in the immediate environment.

There are no indications that contamination with PFAS on the Schiphol site has led to increased levels of PFAS in the immediate vicinity. There are areas in the country with additional advice when it comes to PFAS exposure, but Schiphol is not listed. Check the GGD website for more information.

Our interest is to create a healthy and safe (living) environment, one that people experience as such. That is why Schiphol operates within the requirements of the law. To handle PFAS as carefully and safely as possible, we work with recognised independent parties. Investigations are carried out by an independent consultancy firm. The Environment Agency checks our work when we reuse PFAS-containing soil. And they check whether the way we temporarily store the soil meets all the requirements. We coordinate how we deal with PFAS with the environment agency, Terrascan and engineering firm Tauw.

No, that is not true. Schiphol does not have a disposal site, only temporary storage facilities for the soil. No leaks have been found at the storage facilities and there is no evidence PFAS has spread out into the surroundings.

The Rijnland Water Board measured PFAS levels at officially designated swimming locations in May 2024. The measured values are well below the advisory value for outdoor swimming water set by the National Institute for Public Health and the Environment (RIVM). This information can also be found at www.zwemwater.nl. For advice on swimming in the water around Schiphol, please refer to PFAS - Hoogheemraadschap van Rijnland (information in Dutch).

Good to know: we have taken our own samples of the sediment on the bottom of the water around the storage sites. No PFAS levels were found there. We consider it important that we know how PFAS contamination affects surface water. Therefore, on our own initiative, we are assessing the extent to which PFAS contamination at Schiphol has affected the quality of the water in the waterways at and around Schiphol. It may take some time before we have concrete results. This is because we are working thoroughly, with a historical investigation and a good measurement plan.

PFAS does not evaporate into the outside air and does not become airborne. Because of all the measures we take when storing contaminated soil, there is no risk of PFAS-containing soil being diffused. These measures are determined based on the 'Netherlands Soil Protection Guideline' (NRB) and are included in our permit.

195,000 tonnes.

The PFAS at Schiphol is mainly in the ground around the fire stations, the (former) fire training site and at locations where an incident occurred in the past. One example is the top of the Zwanenburgbaan Runway, where a Boeing skidded off the runway in 1997. Firefighting foam containing PFAS was used in training exercises and incidents until 2000. From 2000 to 2020, no PFAS-containing foam was used in training. And as of 2020, all firefighting foam at Schiphol has been PFAS-free.

The soil depot is located to the north of Schiphol, between the A9, A4 and A5. All temporary storage facilities are located there.

Since 2016, we have been routinely testing for PFAS in excavation work. The research company Terrascan does the research. They take a sample of the soil, test it in the lab, and after two weeks we have the results. These can be divided into three categories.

1. We do not find PFAS contamination.
2. We find such low levels of PFAS contamination that we are allowed to reuse the soil.
   These levels do not pose a danger to people and the environment. Therefore, we may immediately reuse that soil again for other construction projects or maintenance.
3. We find levels of PFAS in the soil that are above the limit for reuse.
   We take this soil to the temporary storage facility where it is stored and covered. PFAS above the limit value does not mean that this soil poses a possible risk to people and the environment. These limit values are in fact much higher. The RIVM and the GGD have determined a standard against which the research results are tested.

This is temporary because we plan to clean the soil at a treatment facility. We are waiting for the permit for this facility.

PFAS at Schiphol is primarily a legacy of the past. A legacy we'd rather not have, but one that we deal with in a careful manner. Based on the Netherlands Soil Protection Guideline and in consultation with the Environment Agency, we have created an approach to safely handle PFAS-containing soil. This management plan is part of our permit. We have several considerations when dealing with every type of soil. To give three examples:

• How should we cover the soil?
  Depending on the PFAS levels, the soil either doesn't need to be covered, only needs to be covered from underneath or needs to be fully covered. When the soil is fully encased, it is unaffected by weather conditions. We overlap the covering material to prevent the contaminated soil from becoming exposed in the event the covering becomes loose.
• Do we need to put clean soil on top of the covering?
  This way, the contaminated soil remains better in place if strong winds, for example, suddenly caused the material to tear.
• Are there extreme weather conditions?
  We do not process contaminated soil in extreme wind (>7 Bft) or very heavy rainfall. In extreme drought we spray water if necessary to prevent diffusion.

That's an internet phenomenon where old photos resurface and are compared to today's reality. We discovered that the covering we used to use was not suitable for long-term storage and would tear due to certain weather influences. We always repaired that immediately. Studies have shown that those tears did not lead to contamination. We have been using the new strong covering for five years now and there have not been any tears. That is also evident from inspections.

The measures we take are sufficient to eliminate the risk of diffusion. Additional measures would only be more damaging to the environment and would not create a safer situation.

The research we conduct involves testing the methods for efficiency, sustainability, speed, cost and safety at different stages. All methods studied can be divided into four categories.

1. Thermal cleaning using heat
Heat can break PFAS down. However, this requires prolonged high heat. If there is insufficient heat or heating time, the PFAS will not break down completely or harmful substances will not be emitted from the chimney. Due to the required prolonged high temperatures, it proved difficult to develop a sustainable method. It simply took too much energy. And a lot of CO2 is released in this process, meaning you can no longer use the end product for anything. This method was therefore not suitable for us.

2. Biological decomposition
This can be done with bacteria, fungi and plants. It's an interesting technology already being used for other types of contamination, but it's still in the early stages when it comes to PFAS. It is not yet suitable to be used for the amount of soil and PFAS concentrations we have in storage. Therefore, biological decomposition does not offer us a complete solution.

3. Keeping the PFAS in the ground
We found this one too tricky. The theory is that by adding a certain substance, the PFAS can be stored for 1,000 years so that it can no longer come out of the ground. So, you don't remove PFAS from the ground, and you don't break it down either. We asked ourselves two questions. The first: what do you do with the soil after that? The second (and biggest): how do you ensure that future generations know the ground contains PFAS and has been treated? We didn't want to take these risks.

4. Washing the soil
The official term is 'wet extraction cleaning'. There are different methods, but the soil treatment facility we have chosen is the most effective for PFAS contamination in the clayey Schiphol soil. Once we start the treatment, we can reuse the cleaned soil anywhere in the Netherlands. We were impressed with the performance of this facility. Instead of flushing 60 micrograms of PFAS from the ground, this installation can flush up to 250, and possibly even up to 1,000 micrograms of PFAS below the reuse standard. This means that more than 99% of PFAS is removed from the soil.

The decision we made now was made on environmental grounds. Transporting the soil to Antwerp and cleaning it in a plant there would have been a less costly option. Then we would not have had to purchase our own facility. We decided not to do this. The cheaper option would have involved many more transport movements, which we wanted to avoid. In addition, we would not have been able to reuse the clean soil at Schiphol. And it is precisely this reuse that we consider important, seeing as we want to be a waste-free airport by 2030.

Every day a location manager walks around the storage facilities at Schiphol and reports weekly on the inspection rounds. Any damage, for example after a storm, is repaired as quickly as possible. This is all recorded in a management plan, which is monitored by the Environment Agency. The inspection reports from the Environment Agency show that they found no shortcomings in our management plan.

In the case of PFAS-containing soil that is suitable for reuse, we will look for a suitable destination for it. And for part of the non-reusable PFAS-containing soil, we will try to find another solution. For example, using it for a large-scale soil application such as a noise barrier.

We cannot currently make the majority of the PFAS-containing soil suitable for reuse. The only alternative is to take it to an approved processor for disposal. Neither option is the sustainable solution for now, nor for the future. We want a solution that fits our goal of becoming a waste-free airport. We found that solution in a soil treatment facility that allows us to reuse the soil at Schiphol.

Once we get the permit, we expect that we can clean all the PFAS-containing soil currently in storage within four years. More ground containing PFAS may be found in future projects, and we currently do not know how much that could be. We have, however, started an investigation in order to get a better understanding of that.

The permit for the soil storage facility (DTOP) was granted with a maintenance period until 1 January 2024. After the expiry of this maintenance period, Schiphol is obliged to restore the situation that existed before the environmental permit was granted. That is why we started the repair work before 1 January 2024. We stopped environmentally harmful activities in a timely manner; the storage facility was empty on time. We are now returning the area to its original state as quickly as possible.

106,000 tonnes of PFAS-contaminated soil. The total (currently known) PFAS-containing soil to be cleaned is 197,600 tonnes. 106,600 tonnes of it comes from the DTOP and is now stored at TTOP2, TTOP3 and TTOP4.

The contaminated soil went to TTOP 2, TTOP 3 and TTOP 4 where it awaits processing at the soil treatment facility.

No. We have coordinated a schedule with the Environment Agency. This schedule consists of two parts: the decommissioning of the site, which will take until July 2024, and the demolition and soil work (until November 2024). The Environment Agency has agreed to this schedule on the condition that we report progress to them every two weeks.

Return it to its orginal condition.

The basis of this technique is widely used in soil treatment. We did have to modify the technique to make it suitable for the clayey Schiphol soil. This modification has also been extensively tested to see if it effectively cleans PFAS-containing soil. The tests were conducted in DEME's laboratory and verified by Terrascan. The results of the laboratory tests, and small- and large-scale trial cleanings were positive. The cleaning process produces 80% cleaned, reusable sand and 20% fine residual sludge. The residual sludge still contains PFAS, but the cleaning process reduces it considerably.

We plan to make bricks out of it. We could transport the residual sludge to a recognised processor, but we have instead chosen a sustainable option. Over the course of two years, we have been conducting tests with Claybens to make bricks out of the PFAS-containing sludge. The theory is that high and prolonged heating causes the PFAS compounds to disintegrate, which makes them harmless. At the same time, bricks can be made. We had the PFAS content in both the bricks and the flue gases checked by an independent laboratory. The results so far are promising.

So far, we have done two relatively small tests in a test oven. The next test will be a large-scale test in a standard brick oven. Contrary to what rumours suggest, these ovens are not located in Badhoevedorp. To do this large-scale test, we need a large amount of our sludge. We will only have this when the soil treatment facility is in place and has been operational for a while. We therefore expect that we can do this test in 2026.

If the permit applications for the soil treatment facility are approved, it will be located next to Zwanenburg Runway in 2025, on one of the former temporary storage sites. In three years, it will be cleaning our soil.

As you can read in the question 'What measures do you take when storing PFAS-containing soil?', the management plan is part of our permit. Based on the 'Netherlands Soil Protection Guideline', we have developed an approach, in consultation with the Environment Agency, to safely deal with PFAS-containing soil. This also applies to soil treatment facilities. When designing the site of the soil treatment facility, we took 3 types of emissions into account:

1. Air
We prevent emissions into the air by installing a spray system at the locations where we cover the soil. By keeping the soil moist, it cannot be diffused and spread through the air.

2. Water
We prevent emissions into water by not discharging water from the site. The cleaning takes place in a closed water system. The water in that system is repeatedly purified from PFAS by an activated carbon filter. All water that falls on the site is drained into waste water basins. The basins are built in such a way that they do not fill up and overflow during a rain shower. Good to know: PFAS cannot get into the air from the water.
* 3. Soil*
We will prevent emissions into the soil by pouring an impermeable floor. The entire installation (and all work carried out there) is on this special floor.