This is obviously not an official website, but the material below has been machine translated by translate.google.com from the German source on the Baden-Wurttemberg Karlsruhe regional website (link below).

Many links below lead to content created at Augustenberg Agricultural Technology Center (Landwirtschaftliches Technologiezenstrum Austenberg) who did much of the chemical analysis and the field and pot trials cited below. .

Much of the research was presented in public meetings and the original presentation files are hosted on the website of the Rastatt District government.

A few editorial notes are in order. The material below is relevant because some of the same PFAS chemicals were in use and comparable levels are found in the soil. Also because similarities in the climate mean that some of the same crops were present. Many of the conclusions drawn were stated in the posters developed for the public information sessions, so please use the links to view them. In some cases I was able to chase down the full published article behind the poster, mostly from the agricultural university publication page. Google translate doesn't do well with terms applied to plants so this could use some work by someone who knows them, but you generally get the idea. Google translate also does not deal with text embedded in images, so in some cases I have provided a poster-specific glossary, also using Google translate.

Please keep in mind that the specific health limits mentioned are somewhat dated. New limits are being rolled out in Germany in 2026. I also have the impression that the crop uptake experiments mostly involved the precursor diPAP which breaks down to produce carboxylates such as PFOA. In Stella PFOA is the primary concern but there are also lower levels of sulfonates. The short chain components such as PFBS are found in the groundwater and additional data is needed to determine whether uptake of these is an issue.

Landwirtschaft (link to original document)

Agriculture

Ensuring consumer protection in the management of PFAS-contaminated land

If soils contaminated with PFAS are used for agriculture, the resulting products may contain PFAS. Experience in Central Baden and Mannheim shows that plants primarily absorb short-chain PFAS compounds and can accumulate them to varying degrees in the reproductive parts of the plant (e.g., flowers, seeds, fruits), depending on the crop. To prevent the entry of PFAS into the food chain, effective measures have been developed in recent years: pre-harvest monitoring (VEM), the derivation of cultivation recommendations from pot and field trials, as well as individual farm consulting and the creation of a management and minimization concept (BeMiKo).

From project to permanent task

These measures were developed in two projects funded by the Ministry of Food, Rural Areas and Consumer Protection (MLR) and implemented in Central Baden and Mannheim:

Project I "PFC-contaminated areas in Central Baden? – Solutions for the cultivation of agricultural crops and preventive consumer safety" (2015 to 2017)

Project II "Dealing with PFC-contaminated areas – individual farm concepts for agricultural management and food safety" (2018 to the end of 2019)

In order to ensure long-term consumer protection and support for affected farmers, the measures will now be continued as a permanent task after the completion of the projects.

Description of the timeline and content of the "PFAS-contaminated areas in northern Baden" projects

Objectives of the measures

Preventive consumer protection and ensuring the safety of marketed local products
Maintaining agricultural production opportunities through adaptation of management
Development of crop production strategies with cultivation alternatives and further development of cultivation recommendations
Gaining scientific knowledge on PFAS uptake by plants on different soils, with different PFAS levels, with and without irrigation, and processing of these study results in order to develop future options for farmers regarding crop production measures and irrigation issues
Support and guidance for farms in the development of individual farm management and minimization concepts in the form of a management plan and guidance for a sustainable security concept

Pre-harvest monitoring (PHM)

Pre-harvest monitoring [data overview] is an essential component of the measures and is intended to provide indications of possible PFAS contamination of the harvested crop in good time before harvest. For this purpose, approximately 14 days before harvest, an official takes samples, which are then tested for PFAS at the Augustenberg Agricultural Technology Center (Landwirtschaftliches Technologiezenstrum Austenberg). This informs the farmer in good time before harvest whether PFAS has been detected in their produce, and if so, in what quantity. In addition, an assessment is carried out based on assessment values. Due to the lack of a comprehensive toxicity assessment by the European Food Safety Authority (EFSA), the state has temporarily and alternatively established these food law assessment values (BUW) for the PFC compounds relevant in the region until a risk assessment is available. Further information can be found under Food Safety. Exceeding the assessment values precludes marketing as food. Pre-harvest monitoring is intended to give producers the opportunity to make a decision about the subsequent marketability of their products before harvest.

In addition to and in addition to pre-harvest monitoring, official food inspection authorities collect plant and animal food samples from the contaminated areas and test them for PFAS by the Freiburg Chemical and Veterinary Investigation Office (CVUA). Sampling of plant and animal food products is generally carried out directly at the affected producers or in downstream trade and marketing facilities. The combination of pre-harvest monitoring and food inspection offers the highest level of safety to prevent food with elevated PFAS levels from entering the market.

All farmers affected by the problem participate in pre-harvest monitoring.

The results of pre-harvest monitoring are published every six months to ensure a high degree of transparency for consumers. They can be viewed here:

Stabsstelle PFAS am Regierungspräsidium Karlsruhe

Results of Pre-Harvest Monitoring

Pot and Field Trials of the Augustenberg Agricultural Technology Center (LTZ)

To further investigate PFAS uptake by crops, the LTZ has been conducting pot and field trials since 2015.

Using pot trials, various experiments are being conducted to measure PFAS uptake by plants from the soil (“soil-to-plant transfer”) and from irrigation water (“irrigation water-to-plant transfer” simulating irrigation with PFAS-contaminated water). The conversion of so-called precursor compounds (complex PFAS compounds, some of which are found in industrial products and waste) into the highly stable PFAS compounds in the soil is also being investigated. The controlled conditions under which the pot trials are conducted are particularly well-suited to elucidating the processes of PFAS uptake by plants and the conversion processes. A disadvantage of such trials is that the results cannot be directly transferred to field conditions. Therefore, additional field trials are being conducted on two different PFAS-contaminated sites in Central Baden that are typical for the region. Here, both agricultural crops commonly found in the region are being cultivated as part of a crop rotation trial, and a variety of rarer crops are being tested for their PFAS uptake. Energy crop trials have also been conducted.

Test results

The pot experiments have shown that almost exclusively short-chain PFAS (PFBA, PFPeA, PFHxA) are transferred to the above-ground parts of the plants. It also became clear that elevated PFAS levels in irrigation water can lead to transfer to crops. Therefore, even the lowest PFAS levels in irrigation water can lead to transfer to the edible parts of sensitive crops such as bush beans and cherry tomatoes.

Previous results from pot and field trials also show that there are significant differences between the different plant species in the uptake of PFAS, particularly in generative plant parts, such as flowers, seeds, and fruits. This has also been confirmed by the results of the pre-harvest monitoring.

A low level of PFAS transfer occurs in the generative parts of grain corn, winter barley, winter rye, oilseed rape, and strawberries, as well as in asparagus spears. A significantly higher level of PFAS transfer into the harvested crop is observed in wheat, triticale, and soybeans, cereal crops and soy field trials, as well as in crops that utilize the vegetative parts of the plant, i.e., leaves, shoots, and roots, such as silage maize, forage crops, or grass.

Preliminary studies (so-called "test trials") with potatoes showed no or very low transfer into the tuber, indicating that potatoes may be suitable for cultivation on low- to moderately contaminated PFAS land. Test trials with sugar beet, millet, and safflower also revealed low levels of PFAS transfer into the harvested crops for these crops. Carrots, in contrast, showed significant PFAS transfer into the green parts of the plant, but no significant PFAS transfer into the roots.

As part of the energy crop trials, miscanthus and perennial silphium were cultivated to determine whether these crops could be used for moderately PFAS-contaminated land and possibly even for phytoremediation. As with other plants, short-chain PFAS compounds accumulate in these two energy crops, particularly in the leaves. However, soil contamination consists primarily of long-chain PFAS compounds, which severely limits phytoremediation. Miscanthus could be burned for energy production, but loses a large portion of the previously absorbed PFAS through the loss of its leaves by the time it is ready for harvest in March. Therefore, phytoremediation of the soil with miscanthus is not possible. Although perennial silphium accumulated 2.5 to 5 g of PFC per hectare in the trials, it cannot be burned due to its high water content and must be utilized in a biogas plant. Since the absorbed PFAS cultivation of agriccompounds cannot be degraded in a biogas plant, they would remain in the digestate, which would jeopardize the safe agricultural use of the digestate.

The list of crops being tested for PFAS uptake in the LTZ trials is constantly being expanded. A brochure summarizing the results of previous cultivation trials is currently being developed.

Derivation of crop production strategies and cultivation alternatives

Cultivation recommendations

The results of the trials and pre-harvest monitoring reveal crops that absorb PFAS to a lesser extent and can therefore be considered alternative crops for PFAS-contaminated sites. However, the factors that influence PFAS uptake in the field are extremely diverse and are currently the subject of various scientific research projects. Therefore, precise predictions of PFAS uptake by plants are currently hardly possible, even with known soil levels. Nevertheless, trends can be identified and recommendations derived on this basis.

Fact sheet: Cultivation of agricultural crops on land with PFC contamination

original link

How can land with PFC levels be used?

original link

Irrigation

Agricultural production on light soils depends on the possibility of irrigation for many crops. Especially in dry springs, watering during the plant germination period is often crucial for success. Specialty crops such as berries, as well as asparagus and other vegetables, have a particularly high water demand, which cannot be met without additional irrigation even in years with moderate rainfall. Farmers typically use groundwater for this purpose.

Agricultural businesses therefore depend on the availability of sufficient water; in connection with the PFAS problem, quality is a second aspect. Previous studies have found a close connection between the intake of PFC-containing water and the deposition of short-chain PFAS in the harvested product, which can lead to relatively high PFAS levels in the produce, especially in plants with high water throughput. Clear regulations for irrigation ave therefore been established. These will be adjusted as needed based on the latest findings.

Requirements for irrigation in PFAS/PFC-contaminated areas – from a water and soil protection perspective – as well as from an agricultural and food law perspective, starting in 2023 (pdf)

original link

Options for treating groundwater for irrigation

In order to ensure the cultivation of specialty crops in the Rastatt/Baden-Baden area, access to uncontaminated irrigation water – generally uncontaminated groundwater – is of key importance. A significant contribution to solving this problem was made within a project funded by the Ministry for Rural Areas and Consumer Protection entitled "Pilot Plants for PFC Treatment of Irrigation Water for Agricultural and Horticultural Crops." Three differently designed water treatment plants from various suppliers were able to meet the quality requirements for the treatment of the contaminated water. A positive result was that short-chain PFAS could be adequately removed or significantly reduced using the activated carbon filters used. This enabled longer operating times for the activated carbon systems than expected. However, this technical feasibility is offset by the economic feasibility, which is more challenging and depends significantly on the constraints of the respective operation and the composition of the water to be treated. Furthermore, it became apparent that a suitable water reservoir is essential for practical operation.

For this reason, another two-year project for PFAS treatment of irrigation water was initiated in 2019. The project, entitled "Pilot Plant in Practical Test: PFAS Treatment of Irrigation Water for Horticultural Crops," was designed to treat PFAS in irrigation water. This project, which involved an activated carbon system designed as a pilot plant for a practical test for horticultural crops, ended in December 2020. The system was designed to irrigate approximately 15 hectares of cultivated land (vegetables, strawberries). The treatment capacity was approximately 22,000 m³ in 2019 and approximately 32,000 m³ in 2020. The pilot plant was designed with three filters connected in series. Each filter container was filled with 3 m³ of activated carbon specifically designed to bind PFAS. In both project years, two filter containers were sufficient to continuously keep the irrigation water virtually PFAS-free. The timing of changing the activated carbon in a filter was determined by the analytical values in the raw water and the filter outlets. A replacement of 3 m³ of activated carbon was required three times over the entire operating period. A 500 m³ storage bag proved to be a successful water storage device – another key component of the plant. The plant exceeded its targets.

Final Report - Pilot Plant for PFAS Treatment of Irrigation Water 2019-2020

original link

Management and Minimization Concept

The further development of general cultivation recommendations into individual farm management and minimization concepts (BeMiKo) aims to ensure preventive consumer protection and sustainable land management. Consumers should be able to trust the safety of local products despite the existing PFAS problem in the region.

The findings obtained so far will be transferred to the individual farm, and a specific management and minimization concept (BeMiKo) will be developed together with each farm. This essentially involves planning crop rotations based on the cultivation recommendations, broken down to the individual agricultural fields, that avoid the cultivation of PFAS-rich crops on soils with PFAS levels.

The basis of the BeMiKo is therefore the cultivation recommendation, which aims to minimize PFAS levels in the crop by combining the PFAS levels in the soil and the uptake behavior of the respective crop. Within the framework of the BeMiKo (Process of Misuse and Use of Food) program, the results of pre-harvest monitoring are discussed on-site, soil tests are interpreted with the farm, and advice is provided on the implementation of cultivation recommendations and other requirements. The increased individual support provided to farms helps implement the highly complex planning for the cultivation of areas with varying levels of contaminants.

The high level of willingness of farms to actively participate in the BeMiKo program is encouraging, thereby fulfilling their responsibility as food producers.

If a farm has decided in an individual case to cultivate a crop that does not comply with the cultivation recommendations, i.e., PFAS contamination in the soil was already known at the time of sowing, it must demonstrate, at its own expense, through appropriate testing before marketing the product that the products comply with the applicable regulations for food or feed. Marketing is only permitted after prior inspection and approval by the responsible authorities.