The quality of our drinking water is safeguarded with extensive monitoring programmes to ensure that the water is healthy and safe. The relevant levels are defined in drinking water legislation and accompanied by specific quality requirements. In this way, drinking water quality is continuously assessed and steps can be taken where necessary to maintain quality.

However, there are gaps in our knowledge about the toxicity of many substances in the environment, and exposure patterns may change in the future due to climate change and adaptation. A lack of toxicological and exposure data means that it is not always possible to estimate the risks that these substances pose for health.

KWR and IRAS have teamed up to tackle these challenges. We are working together on the further development of risk assessment for substances (and particularly emerging substances) in water, using both existing and innovative methods in the fields of epidemiology, exposure studies and toxicology to fill knowledge gaps. Knowledge about concentrations in the environment, human exposure through water and other pathways, and toxicological and health data can support the well-informed decisions required from policy, society and business to cope with contaminants.

The Academic Collaborative Centre for Healthy and Safe Water serves as a point of contact and central platform for projects addressing research questions from policy, business, education and the drinking water field. It establishes a bridge between science and practice. The centre provides an environment where relevant theories, models and tools for the determination of the toxicology and exposure of substances (and particularly emerging substances) in drinking water can be tested in practice, where results can be shared and relevant results can be published. New ideas and questions from society are given concrete form in projects and research. In this way, knowledge and expertise are transformed into applicable solutions.

At the Academic Collaborative Centre, IRAS and KWR worked together on three domains and considerable amounts of knowledge have already been exchanged between experts from the two organisations. Projects at the centre may address one or more of the following domains:

• Toxicology: the effects of substances on health. For more information: Toxicology
• Exposome: the total package of environmental factors to which people are exposed during their lifetimes and the effects on health. For more information: Exposome
• Wastewater screening and non-target screening (NTS): innovative methods for mapping out exposure. For more information: Wastewater screening and NTS

If you have any questions about substances, the levels of those substances in the environment and human exposure, or their possible adverse effects on health, please contact Renske Hoondert (KWR).She is also in close contact with the IRAS coordinator. We also look forward to engaging with students who would like to research the topics listed here.

Domain 1: Toxicology

The effects of substances on health

Although more and more substances are found in the environment, the toxicity and toxicological mechanisms of those substances are mostly unknown. This lack of information often makes it difficult to estimate the potential risks associated with substances in water for the health and the environment. A conservative, safe threshold can be derived on the basis of the threshold of toxicological concern (TTC). However, a more accurate estimate of potential risks is often desirable in order to avoid unnecessary measures and concerns.

In addition to identifying the potential risks of individual substances for which toxicity data are not available, it is also important to have a clearer understanding of the potential risks of mixtures of substances for people and the environment. Drinking water sources contain complex mixtures of various substances in low concentrations, the exact composition of which is not always known. By, for example, drawing on knowledge about mixture toxicity and effect-based monitoring tools it is possible to make a better estimate of potential harm.

Current guideline values for substances, including those in water and drinking water in particular, are still often based on knowledge from animal trials. Those trials are not only expensive and time-consuming, they also fail to deliver the most relevant toxicological knowledge. Given the ethical and scientific considerations relating to replacing, reducing and refining animal trials, alternatives are increasingly being used. They include new approach methodologies (NAMs), computermodellen or the use of epidemiological information.

Work is taking place to establish a structured, evidence-based approach and other methods to implement alternatives to animal trials for deriving risk thresholds and guidance values in the context of water quality (next-generation risk assessment). We are engaging in research looking at specific toxic end points (such as immunotoxicology and neurotoxicology) and specific groups of substances, such as micro- and nanoplastics and transformation products of substances (and particularly emerging substances).

As well as collecting information about the toxicological mechanisms of substances, it is also important to use existing and innovative methods to map out exposure to substances via drinking water better at both the macro- and micro-levels. This varies from concentrations in the environment and water sources to those in the human body.

When research produces new insights into the toxicity of specific substances, questions about levels of exposure can be explored further in the Wastewater Screening and NTS domain.

Domain 2: Exposome

The total package of environmental factors to which people are exposed during their lifetimes and the effects on health

The aim of exposome research is to understand how individual environmental factors, and their interactions, affect health. Drinking water, as a primary necessity, cannot be excluded here. Exposome research is therefore also relevant for the water sector. IRAS is taking the initiative to strengthen the knowledge ecosystem associated with this topic, while KWR is in a position to advance water research (domestic and international) in this field.

The availability of epidemiological data is increasing, there is a growing wish for transparency about environmental and water quality, and health is increasingly seen as something that individuals can actively influence. Some government authorities, such as municipal authorities, are developing policies to become healthy ‘blue zones’. KWR research is focusing on, among other things, identifying all potential and future exposure through water and drinking water, and other exposure pathways. That research can be used, for example, to work on prevention during product development (Safe and Sustainable by Design). The risks of combined and mixture exposures can be assessed on the basis of concentrations measured in the environment and the use of bioassays.

With IRAS, new statistical methods can be used for this purpose and links can be established with health data. With its work on risk perception, KWR plays a unique role in this research field.

Domain 3: Wastewater screening and NTS

Innovative methods for mapping out exposure

A clearer picture of the concentrations of substances in the environment and exposure to them is an essential part of substance risk assessment. The level, frequency and duration of exposures are measured or estimated for individuals and populations. This may include efforts to identify the source of exposure and the contribution of different exposure pathways by using methods that provide an insight into the distribution of substances in the environment.

Wastewater can be an important source of information about exposure, pathogens, health and the lifestyle of the people in the service area of a wastewater treatment plant. For example, wastewater analysis can provide information about recreational drug and medication use, the use of food and other products, and exposure to substances such as pesticides. The same substances, or their metabolites, can also be measured in human tissues such as plasma (blood) and urine. When substances are found in the body, it is certain that the substance has entered or passed through the body. However, in wastewater testing, more evidence is required to arrive at the same conclusion.

KWR’s wastewater research analyses multiple components and metabolites, allowing us to determine plausibly whether a substance has passed through the body, or been discharged directly into wastewater. Measuring substances or their metabolites in human tissues can determine the exposure of a single individual, while wastewater research provides insights relating to an entire population. In this way, the most relevant substances and exposures can be identified (screening function).

In many cases, target screening is no longer adequate to monitor all unknown substances (in wastewater). Suspect and non-target screening (NTS) provide a solution here. These are broad, generic monitoring methods that can detect a multitude of chemicals simultaneously and at low concentrations, resulting in a long list of thousands of unknown substances for each sample. Then we go looking for the harmful and/or relevant substances.

When toxicological knowledge about these relevant substances is lacking, this gap is addressed in the Toxicology domain.

In addition, we are working on developing methods to link wastewater search results to health effects on the basis of cohort studies.

A related topic on which KWR and IRAS will work jointly is the development of analytical and statistical methods to measure biomarkers in wastewater. These measurable indicators of biological condition, disease or lifestyle will then be correlated with data about substances in water, helping to provide a more complete picture of exposure and the associated health risks.

The Academic Collaborative Centre for Healthy and Safe Water is an alliance between Utrecht University (IRAS) and KWR.

Contact

If you have any questions about substances, the levels of those substances in the environment and human exposure, or their possible adverse effects on health, please contact Renske Hoondert (KWR). She is also in close contact with the IRAS coordinator. We also look forward to engaging with students who would like to research the topics listed here.