Agriculture is an important but overlooked source of water pollution. Ground-breaking work by WLE and partners has made the murky world of agricultural water pollution a little clearer.
As the global population increases and shifts to diets richer in meat and calories, agricultural expansion and intensification are also raising levels of water pollution. Farming contributes large amounts of nutrients, pesticides, salts, sediments, organic matter, pathogens and emerging pollutants to water bodies, with adverse consequences for the environment, human health and sustainable development. Despite this, agricultural water pollution (AWP) has received insufficient attention in global water debates, including water quality debates. Over the past decade, WLE has been working to shine a light on this important topic.
Until recently, information on AWP was limited and scattered, making it difficult to establish relationships between the causes and effects of water pollution or comprehend the global scale of the problem. In response, WLE worked with FAO and IWMI to produce More people, more food, worse water?, a detailed global review of AWP, and estimated selected pollutant levels to 2050 under alternative climate change and socioeconomic scenarios. This was followed by a paper discussing the key knowledge gaps and research needs that had been brought to light by the review.
More people, more food, worse water? was the first publication to systematically compile global information about AWP. By providing a comprehensive review of the various types of pollutants and key drivers of AWP, it revealed the global extent and significance of water pollution – as well as the urgency with which this previously overlooked issue needs to be addressed. Similarly, by identifying specific aspects of AWP that require more study and data, the paper on knowledge and research gaps served as a much-needed call to action for the research community. These publications have quickly become key resources for researchers and have been widely cited in the past few years.
Compiling and structuring the scattered information on AWP in a clear and useful way has been the biggest challenge of this work to date. Moving forward, however, the most significant obstacle to future research and action is a lack of data. To fill in data and knowledge gaps, the paper on knowledge and research gaps has identified several key areas requiring additional investigation:
- Develop markers and models to track the flows and concentrations of waste through water bodies and help identify the sources of pollutants.
- Collect data on poorly understood contaminants of emerging concern (CECs), such as hormones, antibiotics and microplastics, and review the effectiveness of voluntary schemes to reduce agricultural CEC use.
- Calculate the costs of AWP in order to raise awareness of the issue and facilitate the development of initiatives to combat it.
- Improve communication and collaboration between researchers and farmers to encourage the adoption of good practices.
For all of these recommendations, special attention should be paid to low- and middle-income countries, where less research has been conducted and little data is available.
Equipped with more data, it will be possible to better understand the mechanisms of AWP and, importantly, to inform policies and practices aimed at reducing agriculture’s contribution to the current water crisis. In particular, quantifying the local costs of AWP and incentivizing farmers to adopt pollution-reducing measures will be of central importance if agriculture is to intensify sustainably without increasing water pollution.