Risks of microbial pathogens and contaminants

Protect humans and the environment with informed risk assessments of microbial pathogens and contaminants

In order to provide sufficient protection for humans and nature, we need to know what hazards and risks  microorganisms and contaminants present, and what is needed to improve the water quality. 

By adequately controlling the health risks to humans and the environment as a result ot exposure to pathogens, antimicrobial resistance and chemical contaminants, the (drinking) water sector, industries and government ensure that water is fit for purpose. We provide the insight into the risks associated with microorganisms, antimicrobial resistance and chemical contaminants, and assist in monitoring and controlling these risks.

Water(cycle) Safety Plans 

KWR conducts risk analyses and assessments and develops Water(cycle) Safety Plans that help determine whether the exposure to pathogens or contaminants can have harmful effects. Risk assessments and Water(cycle) Safety Plans help support safe drinking water supply (central or decentral), safe reuse of (waste)water, safe bathing water and industrial water. In this work we focus on questions such as: What are the risks of reuse of water for different purposes, such as drinking water, process water or irrigation water? Which treatment steps are needed to control these risks? Which pathogens and/or contaminants are present, how do they spread in the environment and where do they come from?

Risks of chemical substances 

Chemical contaminants are increasingly present in the environment and water all over the world. We assess whether chemical substances can have hazardous effects, and whether exposure to them (through water) presents a risk to humans and the environment. We thereby support decision-making and measures aimed at mitigating the risks, including in emergency contexts.  

We apply and develop a variety of risk assessment methods, including predictions using computer models and effect-based measurements (bioassays), and assess both the risks of individual substances as well as the combined and cumulative exposure, including in contexts of lifetime exposure to environmental factors (exposome). Read more on our page about toxicological risk assessment. 

Pathogens and antimicrobial resistance 

Microbial pathogens can end up in the water cycle in several ways: as faecal contaminants from sewage discharges, bird droppings or land runoff. It is important to understand the possible sources of pathogens and their spread in water systems. We develop and maintain a knowledge bank and model on the effect of water treatment processes on pathogens and antimicrobial resistance and we use the Quantitative Microbial Risk Assessment (QMRA) system for rapid and effective risk analysis. Here are a few examples of KWR’s research projects in this area: 

Risk of pathogens from regrowth

There are also pathogens, such as Legionella pneumophila and other opportunistic pathogens, that can grow in water under the right conditions. Knowledge about the conditions under which this growth can occur in the drinking water system or outside of it enables targeted measures against such growth/regrowth. In this area KWR conducts research for example into: 

Models to predict behaviour of microorganisms 

Hydrodynamic, treatment and risk models allow for an integrated assessment of the safety of water systems. These tools can also be used to develop predictions and scenario analyses for new applications, such as the reuse of wastewater or greywater, and for the development of scenarios for climate change or improvements in wastewater treatment. KWR uses and develops models to predict how microorganisms survive and spread in water. Here are a few examples of KWR’s research projects in this area: 

Undesirable growth of microorganisms  

The growth of microorganisms that cause no diseases can also present risks – for instance in drinking water systems. Biofilm formation, biofouling and regrowth can lead to risks to public health, consumer complaints, technical problems, or exceedances of regulatory standards. Such undesirable biological activity needs to be detected on time and tackled with effective measures. Armed with the knowledge provided by KWR, it is up to the drinking water sector, industry and the public authorities to reduce to a minimum the possible risks of undesirable growth of microorganisms in process management. Here are a few examples of our research in this area: 

WHO Collaborating Centre for Water Quality & Health

KWR is a WHO Collaborating Centre for Water Quality & Health: our knowledge is applied worldwide, for example, in the development of water quality standards that help reduce infant mortality due to infectious diseases, unsafe drinking water and poor sanitation.