January 20th 2026 (13.00 – 17.00 h) – TNO, Utrecht 

On Tuesday 20th January 2026, from 13:00 to 17:00, the NVT Risk Assessment section will organize its annual symposium. The session will be hosted by TNO Utrecht and can only be attended in person. During the symposium, various aspects of risk communication will be discussed by experts from different organizations.

Location: TNO, Princetonlaan 6, 3584 CB Utrecht

Program
13.00 – 13.20 Registration
13:20 – 13:30 Welcome
13:30 – 16:30 4 main topics
- Misperception and miscommunication: Barriers and opportunities for effective communication about risks from chemical substances Tom Jansen (RIVM)
- Risk communication with the public: How both exposures and perceptions shape our message Manon Vaal and Marja Elders (GGD)
- Coffee break
- Seeing is believing: Better insight into exposure through Video Exposure Monitoring Sander Ruiter (TNO)
- Case-study: t.b.a.
16.30 – 17.00 Closure, drinks & networking

Are you curious about this topic? You can register for the meeting by sending an email to Sabine Jetten (sabine.jetten@tno.nl).
- Email subject: “Registration NVT symposium – January 20th”.
- Report your name, affiliation and NVT membership status* (yes/no) in the email.
- Registration closes on December 31st 2025

*NVT-members have priority during registration.

The post Symposium – Risk is not just a number: How to communicate accurately and understandable in complex cases? appeared first on Nederlandse Vereniging voor Toxicologie.

‘Understanding chemical micropollutants in water’
Our drinking water: monitoring & water quality protection

Together with KWR we played a ‘serious game’ in which we dove into drinking water quality and threats to our drinking water sources.

The post Summary and Presentations | Serious game: ‘Understanding chemical micropollutants in water’ | Section Risk Assessment | October 4th 2022 appeared first on Nederlandse Vereniging voor Toxicologie.

One substance – Multiple assessments
Titanium Dioxide considered from a food and pharma perspective

The post One substance – Multiple assessments | Summary and links to presentations appeared first on Nederlandse Vereniging voor Toxicologie.

Theo Vermeire – General introduction (presentation)

Theo provided an introduction to mixture toxicity, hazard and risk assessment, explaining definitions and currently ongoing initiatives worldwide. Theo provided further information on the different available risk assessment approaches, as e.g. the assessment approaches of SCHEER and US-EPA and the WHO framework for risk assessment of mixtures. Attention was paid to the problem formulation with regard to both exposure and hazard assessment. In a recent publication of Herzler (2021) further information is provided on which mixtures should be considered, e.g. substance which act together, individual substances of high concern, as not all mixtures will be considered for mixture risk assessment and risk management approaches.

Bruno Dujardin (EFSA) - Combined exposure to multiple chemicals - EFSA’s recent achievements and future perspectives (presentation)

Bruno spoke about ongoing initiatives and activities on mixture toxicity within EFSA, especially for non-intentional exposure to mixtures. Initially, the focus was at pesticides, with the Cumulative Assessment Groups (CAGs) for thyroid and CNS effects. In parallel, a guidance on risk assessment of combined exposure to multiple compounds was also issued.

Cumulative risk assessments were performed (2019-2020) retrospectively with focus on acute and chronic exposure to CNS and chronic exposure to thyroid. It included a hazard part (identification, characterization, cumulative risk assessment groups), an exposure part, based on market sampling (120.000 samples) which were combined with consumption data (20.000 subjects), and resulted in a risk assessment part with an uncertainty analysis. Main findings were: 1) the outcome is driven by a limited number of compounds 2) highest exposure was often due to 1 pesticide, 3) model estimations are very conservative, leading to an overall conclusion that the cumulative exposure to pesticides that have chronic/acute thyroid/CNS effects does not exceed the thresholds of regulatory consideration.

Future actions on the cumulative risk assessment of pesticides are scheduled by EFSA, in cooperation with DG Santé, e.g. prioritization of new CAGs. Furthermore, by 2030 EFSA and partners should be equipped for implementation for risk assessment of multiple chemicals, with a focus on dietary and non-dietary exposure for human health, with a stepwise implementation for dietary and aggregate exposure to pesticides and chemical in general, and with further development of methods (harmonized grouping criteria, OMICs data, aggregate exposure) and tools (open source).

An EFSA guidance document, on hazard driven criteria and prioritization methods, is to be expected to be finalized by December 2021.

Stephanie Melching – Kollmuss (BASF) - Experiences with cumulative risk assessments in the agrochemical industry and views (presentation)

Stephanie shared the experience of Croplife on the cumulative risk assessment addressing different compounds (within the group of pesticides), products and applications. As an introduction into the EU approach, initially work was started with establishment of CAGs to cover all relevant target organs, together with performing probabilistic exposure and risk assessments. As also presented by Bruno, from the retrospective cumulative risk assessments, the thresholds for regulatory consideration were not reached, after hazard and exposure-based refinements. However, future work is required, as is indicated in the EFSA/DG Santé action plan. This would also include prioritization with regard to hazard assessment (relevance CAGs, number of compounds in CAGs, dose at which the effect occurs, excluding compounds with low individual hazard quotients) and exposure assessment (realistic retrospective exposure, focus on major crops and uses). Croplife looked at specific groups, e.g. liver (with a focus on primary lesion, rather than the secondary lesions) or the reproduction/developmental CAGs. In addition, prioritization based on exposure is required. In order to avoid extensive refinements in mixture risk assessment, it is proposed to refine upfront by e.g. apply more stringent criteria to substance for inclusion into CAGs, consider only compounds for which the common toxic effect is very close to effect driving the reference value, use realistic exposure scenarios (e.g. maximum market share), monitoring background exposure, etc. Future challenges are aggregate exposures, availability of open data bases and risk management.

Lonneke van Leeuwen (RIVM, bureau REACH) – The EU Chemicals Strategy for sustainability towards a toxic-free environment: A Mixture Assessment Factor under REACH (presentation)

Lonneke presented on the EU Chemical Strategy for Sustainability (CSS) and recent ongoing work on the Mixture Assessment Factor (MAF) with a focus on the environment.

2009 is taken as a starting point with the Kortenkamp ‘State of the art report on mixture toxicity’. It concludes an assessment can be done, but should it also be regulated? In 2016 the RIVM published a thought starter on this topic. This report introduced a data driven mixture assessment factor (MAF) for the environment, and indicated that further work was needed to quantify a MAF. In 2020 the EU CSS was published describing a route to a toxic free environment with the goal to better protect human health and the environment and boost innovation. One of the strategic priorities to achieve this is to build a stronger EU legal framework to deal with mixtures. The focus is on unintentional mixtures.

In 2021 the RIVM has a publication in preparation that uses monitoring data for EU surface waters to identify trends in number of chemicals responsible for toxic pressure due to cumulative (environmental) exposure.

The first outcomes show time-place combination where in most situations 1 or 2 chemicals are present. There are only 376 time-place locations with more than 25 substances present. Further, it was observed that a large portion of the toxic pressure on freshwater bodies (> 90%), is caused by 20% of the chemicals. The chemicals that cause the issues are different between the monitoring locations. The current monitoring data shows that not all surface waters in the EU are properly protected. A general reduction of the RCR for single substances to 0.33 leads to an large improvement of the protection of EU surface waters.

RIVM will further investigate whether the same observations can be made based on a wider set of freshwater modelling data.

Annette Wilschut (DSM) – Mixed feelings (presentation)

Annette gave us a warming up for the discussion on the proposal for a MAF. Industry is recognizing the issue of combined exposure, however, is questioning whether the MAF is the right solution. How to balance the aim and the impact of the measure? Will the MAF solve the issue (e.g., legacy chemicals)? Is it proportional & targeted (e.g., via other targeted frameworks/permits)? What is the scientific basis (i.e., more insight in environmental compared to human risk)? How will it be implemented (e.g., prioritization, one-fits- all solution)? According to Annette, the complexity of the situation does not warrant a generic MAF. A set of targeted science-based solutions is the best way forward.

Discussion

There was a lively discussion from all areas of the playing field with experts highlighting the pros and cons of a generic MAF:

• Risk management has been trying to handle this for 30 years. When does the precautionary principle take over from science-based solutions?
• Only a few chemicals determine the effects, the balance does not seem right in this respect.
• Is there really an issue? Let’s target the active substances.
• Would the focus on better exposure and mechanistic data (and making this data publicly available) give us the opportunity for a more targeted approach to come to the critical scenarios and protect human health and the environment?

Diverging opinions were expressed. In the end it is up to policy makers to decide on the best approach in the coming years. Will this be a more general precautionary approach or a science based data driven approach in the end … The future will show us!

The post Autumn symposium: Mixture Toxicity appeared first on Nederlandse Vereniging voor Toxicologie.

 Online - Autumn symposium:

‘Mixture toxicity’

 October 5th 2021 (13.00 – 16.00 h)

 For many decades one substance-one risk assessment has been the standard in regulatory risk assessment. However, real life exposure is not limited to one chemical, and health and environmental risks of chemicals are not necessarily independent of each other. Over the last years slowly but steadily more approaches to evaluate the risks of exposure to chemical mixtures, taking into account possible interactions like synergism and addition, have been developed. It started with the evaluation of mixtures of similar chemicals with a common mechanism of action, like polycyclic aromatic hydrocarbons and dioxins, and moved further forward to intentional mixtures of chemicals, to UVCB’s and now even unintentional environmental mixtures. The topic is high on the political agenda.

In this autumn meeting of the NVT Risk Assessment Section, an overview of the current state of the art of the toxicological risk assessment of chemical mixtures will be presented as well as the most recent regulatory approaches installed by EFSA and ECHA and the position of industrial stakeholders.

We hope you all will have an inspiring, thought-provoking and informative meeting.

Program

You can register for this meeting by sending an email to Jacqueline Steenbergen- Biesterbos (j.w.h.biesterbos@nvwa.nl). Please report “Registration NVT autumn symposium – 5 October” in the title of the email and report your name and affiliation in the email itself.

A few days previous to the meeting you will receive an invitation via MS Teams which contains the link to the session.

The post October 5th Mixture toxicity -Autumn Symposium appeared first on Nederlandse Vereniging voor Toxicologie.

‘Alles wat u altijd al heeft willen weten over PFAS’

5 November 2020 (13.00 – 17.00 uur) – NVWA, Utrecht

Locatie: NVWA, Graadt van Roggenweg 400, Utrecht

Voorlopig programma:

U kunt zich aanmelden door een email te sturen naar Monique Nagtegaal (m.nagtegaal@nvwa.nl). Vermeld hierbij “Deelname NVT najaarsvergadering – 5 november” in het onderwerp. Vermeld ook uw naam en affiliatie in de mail.

The post ‘Alles wat u altijd al heeft willen weten over PFAS’ 5 november 2020 appeared first on Nederlandse Vereniging voor Toxicologie.

Online - Najaarsbijeenkomst:

‘Mengseltoxiciteit’

5 oktober 2021 (13.00 – 17.00 uur)

The post Save the date! appeared first on Nederlandse Vereniging voor Toxicologie.

Introduction

As a short introduction, Professor Annemarie van Wezel, University of Amsterdam, gave a general overview on PFAS. PFAS use is really wide-spread, in almost all industry branches and in many consumer products. OECD list contains >4700 PFAS substances. Only 107 substances are currently registered under REACH. PFAS are also called ‘forever chemicals’ because of their persistence. They are widespread, and present in 99 of 100 environmental samples.

The main health effects are effects on the immune system, on the liver failure, on renal function and on thyroid hormone levels. Because of the heterogeneity it is difficult to derive general health levels.

For humans, dietary intake is the main route of exposure.

In 2020 EFSA has proposed a single group Tolerable Weekly Intake (TWI) of 4.4 ng/kg bw per week for the sum of PFOA, PFNA, PFHxS and PFOS. Europeans partly exceed this TWI.

Worldwide PFAS is found in environmental organisms. Most reported PFAS concentrations in the environment are below their predicted no effect concentration. However, our understanding of the toxicity is incomplete, due to lack of information on new PFAS, precursors and degradation products and mixture toxicity.

Annemarie illustrated that both in the Green Deal and in the EU Chemical Strategy, essential use and benign by design (or safe and sustainable) are important issues, that need to be further worked out. She advertised an EU project, PERFORCE, that started in January 2020, that is an innovative training network to train a new generation of innovative early stage researchers, so that they will be able to face current and future challenges and to convert knowledge and ideas into products and services for economic and social benefit.

Statement: The EFSA opinion for 4 PFAS should be summed to 4000+PFAS.

30 out of 90 people voted in favour.

A few remarks were made via the chat: what are the advantages /disadvantages of creating a single limit on all 4000+ PFAS when the group of chemicals is so diverse?   An advantage would be a more inclusive risk assessment, but a disadvantage is that a lot of tox data has to be available.

Another question was whether it would be possible to use toxic equivalence like the TEQ for dioxins Instead of gathering all tox data, or are the adverse effects too different? Another participant referred to an RIVM paper on relative potency factors .

A third question was whether background levels only originate from pollution? The other sources are one of the big unknows. There are several activities related to pollution (e.g. at airports where fire fighter foams were used). Also paper mills might have a relevant contribution, according to a recent exploratory study by RWS. Different investigations are going on to further map the sources.

Statement: Research focus should be on possibilities how to replace PFAS by benign alternatives. A majority, 60 of 90, raised their hand. It was also indicated that also non-chemical alternatives should be considered.

Determination of PFAS limits in soil

Arjan Wintersen of the Dutch National Institute for Public Health and the Environment (RIVM) presented the determination of PFAS limits in soil, prepared together with his colleague Piet Otte. There are three building blocks used in setting Environmental Quality Criteria for soil: Human health risk limits, ecological risk limits (covering both direct and indirect (via food web) exposure) and “other” (risk) limits, which may be, e.g., background levels. RIVM is responsible for preparing science-based advisory limit value, the Ministry of Environment subsequently decides on the legal limit values.

Depending on the use of the soil, differently criteria are developed. When used for agriculture or designated as “nature”, a stricter limit value applies than for residential use; for industrial use the least strict value is applied.

At the moment, only two PFAS are significantly present in Dutch soil: PFOS at 1.4 µg/kg dry soil and PFOA at 1.9 µg/kg (95^th percentiles). Higher concentrations are found in top soil than in subsoil and predominantly in built areas, not in rural areas or areas designated as nature. For PFOA, there is a clear link with its source, Nemours in Dordrecht, as its concentration decreases exponentially with the distance for the plant. There are no indications other PFAS like GenX are structurally present in Dutch soil.

The current soil standards addressing human health effects were based on Tolerable Daily Intakes (TDI’s) derived by the RIVM some three to five years ago. They vary between 6-21 ng/kg bodyweight/day for PFOS, PFOA and GenX. These are well above the current background values in soil. However, this year EFSA has derived a Tolerable Weekly Intake (TWI) of 4.4 ng/kg bodyweight for the sum of PFOS, PFOA, PFNA & PFHxS, which corresponds to 0.63 ng/kg bodyweight/day. Point of Departure was a Benchmark Dose Level (BMDL) of 17.5 ng/mL in blood serum of breast of children, associated with a reduced immune response.

Ecological risk limits were based on the relative number of species affected at certain soil concentrations of PFOS, PFOA or GenX, either directly or indirectly via the wood web. Due to the biocumulative properties of PFAS, the indirect limit values are up to nearly two orders of magnitude lower, and thus determine the limit to be used. These are still above the background valuers, but less than one order of magnitude.

Arjen concluded by summing up what we still do not know, e.g. the transfer and accumulation of PFAS from soil to crops and farm animals. After his presentation quite a number of questions were asked, e.g.:

• Are there other sources than man-made PFAS in the soil background levels?
• Unknown, but RIVM will look into this issue
• What about levels in groundwater?
• Nation-wide Research is on-going, will be published beginning of next year
• Has intake of PFAS via supermarket bought food been taken into account in PFAS exposure calculations?
• No, that is not in the RIVM model (valid for any substance exposure via the environment)

To conclude Arjen put a statement to the vote: “The PFAS that we measure in the environment are only the top of the iceberg.” It was supported by 40 of the 80 odd attendants of the symposium. Arjan himself left the answer open and stated PFOS and PFOA are the main PFAS in soil, but that it might be different for other compartments, depending on the mobility and the affinity of the PFAS (for components in the compartment concerned).

Policy Consequences

Marije Schouwstra, policy coordinator at the Ministry of Infrastructure and Water management (IenW) introduced us to 50 years of soil policy. In soil policy there is a balance between protection of the soil and the use for economic and social purposes. The basic principles are prevention and remediation. The approach in policy was that all contamination should be eliminated; remediated sites should be fit for all possible future functions. With PFAS a new kind of pollution was introduced: omnipresent despite a prevention policy. Such a wide dispersive use was not addressed in the policy.

Within the soil policy, according to the Standstill principle it has to be prevented that cleaner sites are polluted as well; if you want to transport soil, you have to be sure that you do not contaminate another site. You need a risk based limit value (risicogrenswaarde) to be able to set a norm, and that takes time.

Marije shared a few lessons learned: Communication in extremely important. The Framework was experienced as tightning the rules. And our regulations have to be adapted to diffuse pollution, there is a need for development of a new methodology to cope with diffuse emerging contaminants.

Statement: I make a conscious choice and try to buy products without PFAS.

30 out of the 90 participants raised their hand. As a consumer it is hard to know if products contain PFAS. But for some products, like rain coats and cooking utensils, you can buy PFAS-free products. It might be indicated on the label. But for a large number of products it is impossible to make a well informed choice.

Statement: We have to phase-out all PFAS, also in essential uses. Only 15 participants of the 90 raised their hand .

Statement: before introducing new substances in production processes, you should proof its non-toxic an non -persistence character.

The majority of the participants agreed: 54 of 90

From soil to (drinking) water

Frederic Béen from the KWR Water Research Institute presented the analytical methods available for determining PFAS in drinking water as well as ways to remove them from drinking water. At the EU-level two limit values have been set for PFAS, established in December 2019: 0.1 µg/L for the sum of the 20 most important PFAS and 0.5 µg/L for the sum of the 4700 known PFAS. The latter value is not yet in vigour, awaiting the development of a suitable analytical method by the EU over the next three years. The new TWI for four PFAS developed by EFSA has not yet been used to derive a drinking water limit, but preliminary calculations using a simplistic approach lead to a value of about 4 ng/L.

Frederic presented the following analytical methods:

1. Total organic/extractable fluorine methods: these are useful for rapid screening, yet not ideal for testing drinking water as their Limit of Detection (LoD) is 0.5 µg/L.
2. Total oxidizable precursors assay (TOPA): only useable for known PFAS, requires further validation and standardization, needs to be adapted to accommodate emerging PFAS as well
3. Broad screening methods: do not need reference standards, will also identify unknowns, but mainly qualitative although more quantitative applications are being developed based on machine learning
4. Comprehensive workflows: including a step-wise combination of available analytical methods to analyse water quality in the Netherlands and develop a monitoring programme targeted at locally important PFAS, a research project of KWR in collaboration with WFSR, RIWA, Water Boards and Dutch drinking water companies.

PFAS are extremely persistent and difficult to remove from drinking water. There is a well-developed method (Granular Activated Carbon (GAC)), that works well for long-chain PFAS but is less effective for the short-chain ones. For the latter PFAS various technologies are in development, but not ready yet.

After his presentation a number of questions were asked, e.g.:

• How do you avoid cross-contamination during sampling (e.g. when the samples wears a PFAS-treated rain coat)?
• This is above all an issue in the lab, as many equipment used contain PFAS. Therefore you have to be careful and make ample use of appropriate blanks
• Should we also use bio-assays to analyse for PFAS?
• Yes, indeed.
• Instead of removing PFAS from drinking water, shouldn’t we try to remove it somewhere else (probably meaning at the source)?
• This discussion is on-going, but there is no decision yet.

From water to livestock to consumers

Jacqueline Steenbergen-Biesterbos from the Netherlands Food and Consumer Product Safety Authority (NVWA) presented their study, in which NVWA investigated whether there is a possible risk for human health due to exposure to PFOA and GenX in food. In 2017 and 2018 PFOA and GenX were found in soil and water due to air deposition of these substances, in Dordrecht and Helmond. Livestock might be exposed if polluted soil, grass or water is consumed. Subsequently, consumers might be exposed via the consumption of products of animal origin. Dietary exposure of children and adults was determined by measuring PFOA and GenX levels in various food items and using consumption data from the Dutch National Food Consumption survey.

The exposure of children and adults to PFOA and GenX via the consumption of cow’s milk, meat (cow/sheep), cheese, yoghurt, egg and eel does not pose a risk for human health.

Despite the fact that the exposure of children and adults to PFOA via the consumption of carp exceeds the provisional EFSA-TDI of 0.8 ng/kg body weight per day, the risk for human health is expected to be low. A TDI is a health based guidance value based on long term exposure. The carp was caught in a fishing pond in the close vicinity of a factory in Helmond. Fish from this pond will probably only, on occasion, be eaten by specific consumers (sport fishermen) leading to short term exposure. Furthermore, the risk assessment of carp was based on one fish and this fish does not provide an overview of the PFOA distribution in fish from the fishing pond.

Based on a comparison with the provisional EFSA-TDI of 0.8 ng/kg body weight per day, the exposure of children and adults to PFOA via the consumption of sheep’s milk might pose a risk to human health. The risk assessment for sheep’s milk is based on experimental transfer data from two sheep that do not show the same kinetics. Compared to dairy cows, the transfer of PFOA to milk in sheep is higher than one might expect. Therefore, no firm conclusion about the human health risk can be drawn. The full report can be found via https://www.nvwa.nl/documenten/consument/eten-drinken-roken/overige-voedselveiligheid/risicobeoordelingen/advies-van-buro-over-de-chemische-stoffen-pfoa-en-genx-in-voedsel.

Krista Bouma from the NVWA stated that for the risk assessment of PFAS in food contact materials (FCM), paper and paperboard are the main concern since PFAS in water and grease repellent coatings of these materials are present as monomers and not as a polymer, meaning they may more easily migrate to the food contained in them. However, data are needed on migration into food (instead of data on food simulants) in order to perform a more precise risk assessment. The NVWA has developed an analytical screening method that they can use on paper and paperboard to identify PFAS’s present. 46 samples (paper and paperboard intended for hot and/or fatty contact) were screened. Significant amounts of PFCA’s C13 and C14 were found, other PFAS’s (PFOA, PFOS, GenX, fluorotelomers) were either not detectable or present in negligible amounts. Further development is also dependent on developments in legislation (maximum residue levels in food versus or migration limits). Further research is carried out by WFSR, PFAS will be determined in easy and fast-food, packaged in paper/paperboard. If significant amounts of PFAS are detected in the food, then also the food contact material will be investigated to establish if this was the source of the PFAS. The report is expected in Q1 of 2021.

Statement: a risk assessment based on exposure via food is not sufficient. Other exposure sources/routes should also be taken into account.

A majority, 50 of 90 participants, raised their hand and agreed with this statement.

Statement: Should PFASes also be banned from non-stick polymeric coatings? Of the 90 participants, 42 agreed.

Fenneke Linker closed the meeting with a final statement: I gained new insights today. The virtual hand of 65 of the of 90 participants was raised! The slides of the presentations will be made available in the Risk Assessment section of the NVT website.

Presentation 1:  Annemarie van Wezel  

Presentation 2: Arjan Wintersen

Presentation 3: Marije Schouwstra

Presentation 4: Frederic Béen 

Presentation 5: Jacqueline Steenbergen-Biesterbos  en Krista Bouma

The post Report on the Autumn Meeting 2020: Everything you always wanted to know about PFAS appeared first on Nederlandse Vereniging voor Toxicologie.

NVT Risk Assessment Section ONLINE Autumn symposium:

Everything you always wanted to know about PFAS

Location: ONLINE

November 5, 2020 (13.00 – 16.30 h)

Program:

You can register for this meeting by sending an email to Monique Nagtegaal (m.nagtegaal@nvwa.nl). Please report “Registration NVT autumn symposium – 5 November” in the title of the email and report your name and affiliation in the email itself.

The post Invitation: Everything you always wanted to know about PFAS Online meeting 5 november appeared first on Nederlandse Vereniging voor Toxicologie.

‘Everything you wanted to know about PFAS’

November 5,  2020 (13.00 – 17.00 h) – NVWA, Utrecht

Locatie: NVWA, Graadt van Roggenweg 400, Utrecht

Preliminary program:

You can register fort his meeting by sending an email to Monique Nagtegaal (m.nagtegaal@nvwa.nl). Please report “Registration NVT Autumn symposium – November 5” in the title of the email and report your name and affiliation in the email itself.

The post ‘Everything you wanted to know about PFAS’ appeared first on Nederlandse Vereniging voor Toxicologie.