Climate change, drought, and rising demand are pushing agrifood systems towards alternative water sources – making questions of quality increasingly harder to ignore. While microbiological contamination has long been a focus of food safety efforts, chemical hazards in irrigation water, aquaculture systems, and treated wastewater are often less obvious – and potentially more insidious, building up through chronic, low-level exposure over time.
A new FAO/WHO report on chemical water quality in agrifood systems highlights this growing blind spot, warning that emerging contaminants – from pesticide residues to persistent pollutants such as PFAS – may enter the food chain through water pathways that remain poorly monitored and poorly understood.
We spoke with Martin Rose, an independent food and environmental chemical safety scientist and former head of the UK National Reference Laboratory for contaminants in foods, who now supports FAO work on food control systems and chemical risk assessment worldwide. Rose explains why chemical water quality is becoming a key concern for the global food safety agenda, the critical role analytical scientists must play within a One Health framework, and what it will take for regulators to keep pace with the evolving chemical risks in the world’s water.
Could you briefly tell us about your background and how you became involved in working with the FAO and WHO?
I am an analytical chemist and spent over 30 years working as a government scientist on chemical contaminants and residues in foods. For part of this time I was head of the UK National Reference Laboratory for contaminants in foods. This work involved conducting surveillance studies to gather data to use for exposure estimates and risk assessment, or to support policy development, and conducting applied research to identify contaminants of concern, to understand how they behave in the environment and enter the food chain, and how they may have an impact on human health.
This was where I first became aware of the work of the UN, through contributions to the UK participation in Codex, being a member of the WHO committee that established TEFs for dioxins, and through supporting various training programmes e.g. on Total Diet Studies to measure exposure to food contaminants.
Since leaving full-time employment and moving into the world of consultancy, I have focused on my activities with the Food and Agriculture in the UN, where I am on a roster of experts who can be called upon to support work on food safety and food control systems. The report on food safety issues related to chemical water quality in agrifood systems was not part of these activities, but was the output of a group of independent experts, called to a week long meeting at FAO in Rome.
The report highlights a growing shift toward alternative water sources in agrifood systems. Why is this happening, what kinds of sources are being used, and why might their chemical quality be more uncertain?
More than 70 percent of freshwater used globally is for agriculture. With increasing global population this means there is increased demand for water. Socioeconomic development may also increase water demand due to shifts in consumption patterns to more water-intensive foods, for example developing edible algae production. Climate change is anticipated to result in more severe and frequent droughts and floods, while also placing an increased demand for water in agriculture in response to temperature rises. With much global irrigation already impacting the environmental flow necessary to maintain ecosystems, further abstraction of water for this purpose is not sustainable. Instead, approaches to increase water capacity must focus on improving governance, efficiency, and innovation.
Water quality has always been an issue, but microbiological contamination tends to be more obvious than chemical contamination because the effects are acute (i.e. ill health is seen soon after exposure), whereas effects of chemical contamination tend to be chronic (i.e. a result of long term low level exposure).
Microbiological contaminants have been a concern for millennia, but whilst some of the chemical contaminants and residues of concern are well established, such as pesticides and veterinary medicines, products used in fertilizers etc., other classes are only recently emerging, such as some persistent organic pollutants including PFAS. The way that chemical contaminants interact with the environment and transfer into foods is also less well understood.
How does the new FAO/WHO report help bring greater attention to chemical hazards in agrifood water, and what does it offer as a first step forward?
The new FAO/WHO report on food safety issues related to chemical water quality in agrifood systems is a starting point to recognize this issue. It highlights the importance of using water with good quality for food production and how important this is to achieving many of the UN sustainable development goals. It can be used to support prioritization of work moving forward, in terms of assessment and management of chemical hazards in water used for food production. The report recognizes changing factors such as climate change, and sourcing from non-conventional water sources (e.g. treated wastewater) for irrigation and land-based aquaculture as a growing practice, have the potential to increase the range of hazards. Future or emerging chemicals that may contribute to food safety concerns through agrifood water sources will undoubtedly arise in future and so a prioritization exercise needs to be regularly updated alongside horizon scanning activities.
From your perspective, what role do analytical scientists play – or should they play – within a One Health approach to water quality and food safety?
Analytical data is key for assessing problems relating to chemical contaminants and residues in water used for food production. It is the backbone to monitoring, understanding and identifying risks. Analytical science is also key for helping our understanding of how new and emerging contaminants move within the environment in measuring our exposure to these compounds. And in understanding how they eventually end up in our food and bodies. The “One Health” approach requires collaboration between the agriculture, health and environmental sectors, and analytical sciences underpin data generation in all these sectors.
Are analytical scientists sufficiently engaged in this space?
Analytical science is well established in measuring quality of domestic supplies and water used by industry. However, systematic monitoring of the quality of water used in the field for food production is relatively underdeveloped. As new and innovative sources of water become more widespread in some global regions, it is critical that such usage is supported by appropriate monitoring to ensure quality and to avoid adverse health outcomes.
Do you think the role of analytical science in food and water safety is fully understood and valued by policymakers?
Many of those working in policy or regulatory functions recognize the need for data and evidence to support their decisions and actions but often do not fully comprehend the value of analytical expertise, especially when more than a routine service is required. Analytical scientists are key when it comes to working on new or emerging contaminants, when metabolites or breakdown products need to be identified and to support studies on transfer and uptake of contaminants.
Analytical scientists are key in developing monitoring strategies for chemical contaminants in agrifood water sources, and in the development, validation, and accreditation of analytical capabilities to assess levels of priority chemicals in water used in agrifood systems. It is also key that standardized sampling and testing protocols, and monitoring plans, are used to evaluate the quality of agrifood water sources. Collecting data to develop inventories/lists of priority chemicals and their chemical properties in order to manage water quality in agrifood systems is critical.
What can national authorities and regulators do to ensure they keep pace with developments in analytical technologies and risk assessment approaches for waterborne chemical hazards?
National authorities should monitor changes in how water is used for food production, especially when these changes include the use of waste water. Horizon scanning should be used to identify emerging contaminants and to understand whether or not these may be an issue in water used for food production. Where food is imported from water scarce regions, checks should include analysis for contaminants that could potentially come from water used in production.
Finally, what role does international collaboration play in addressing chemical water quality issues in agrifood systems and food safety?
Demands on water are increasing globally resulting in a variety of common issues, plus some localized ones. Food is a global commodity and is widely traded, meaning even local issues are important for importing countries. Competent authorities and other relevant organizations at a national or regional level need to be supported at an international level by the development of guidance (e.g. from Codex), use and sharing of horizon scanning activities, research on transfer and uptake of waterborne contaminants into food and feed, and in methods to assess and manage food safety risks as they arise.
Newsletters
Receive the latest analytical science news, personalities, education, and career development – weekly to your inbox.
