Published on The Water Blog

Dunning-Kruger, groundwater quality, and avoiding a collective moral failing

This page in:
Woman measures irrigation water with digital PH meter in watering canal. Photo Credit: © [Deyan Georgiev] / Adobe Stock Woman measures irrigation water with digital PH meter in watering canal. Photo Credit: © [Deyan Georgiev] / Adobe Stock

The Dunning-Kruger effect is a cognitive bias whereby people vastly overestimate their competence in a given domain, largely as a function of their being unaware of just how much it is they don’t know. When it comes to groundwater, we are suffering from a global, collective version of the Dunning-Kruger effect: our perceived ability to continue relying on groundwater as a primary source of clean water far exceeds our actual ability to do so. 

The fact that it is concealed underground has long allowed us to operate under the assumption that all is well with the water underfoot. Out of sight, out of mind. But research conducted in the last half century has gradually uncovered the uncomfortable truth that our assumption was based not on what we knew, but rather, it was a function of what we didn’t know: that groundwater was, and continues to be contaminated, both because of human activities on the surface, but also as a result of natural processes. And it is far more widespread than previously believed.  

This is a big problem. Groundwater - which accounts for 97 percent of all freshwater on earth - is essential to human welfare and underpins nearly all economic activity. Over one- third of the world’s population relies on it as a source of drinking water and it supplies around 40 percent of irrigation water and 25 percent of industrial water globally. It is also vital for maintaining a great number of terrestrial and aquatic ecosystems and is central to climate change mitigation efforts. But when groundwater quality is compromised the consequences for human health, agriculture, and the economy are far reaching and can span generations.

Take arsenic, for example, a favorite poison of historical murderers, it is also the world’s most important natural groundwater contaminant. Over 70 countries have reported natural arsenic contamination in drinking water supplies, posing serious risk to the health of at least 150 million people. Yet until the 1990s it was given little attention, primarily because we simply did not know to test for it.

Long-term exposure to arsenic has an array of adverse health effects. They range from painful and disfiguring skin conditions that can condemn entire families to social ostracism, the knock-on effects of which can trap entire households into multi-generational cycles of poverty, to numerous cancers, disturbances of cardiovascular and nervous system functions, and eventually death. 

Similar to other harmful contaminants, a characteristic effect of chronic arsenic poisoning is its latency. Skin conditions typically take two to five years to develop. Mortality from cancers and heart disease can peak years or decades after exposure has stopped, meaning that countries that are currently struggling to control exposure will face a significant disease burden related to arsenic exposure well into the future. This has significant socio-economic implications. In Bangladesh for example, the cost of lost labor attributable to arsenic exposure over twenty years is estimated at US$13 billion; many times more than the estimated cost of mitigation, which is a few hundred million dollars. 

Human-generated contaminants meanwhile are far more diverse, with new compounds being developed daily, creating a significant challenge for groundwater resources management and protection.  The United States alone receives notices for the release of more than 1,000 new chemicals into the environment each year—or around three new chemicals per day. Keeping up with such a growing range of risks is difficult even in countries with significant resources and nearly impossible in developing countries.

With human-generated contaminants, it is not just ongoing pollution that is of concern, but the legacy of polluting activities that stretches back many decades. The drive to increase food production has polluted many shallow aquifers with nitrates from fertilizers and pesticides. Meanwhile, many urban aquifers have been blighted by a century or more of mismanagement of industrial chemicals and improper waste disposal. Regardless of the source of pollution, contaminants may travel slowly through the ground for months or years until intercepted by a pumping well. By this time, the stores of contaminants in the soil and aquifer are significant and can continue to pollute abstraction wells for years, even after the source of pollution has stopped.

So where do we find ourselves today? Despite all we have learned, the information at our disposal remains fragmented. Robust monitoring of groundwater resources tends only to happen in countries with the most resources. The implication is that we don’t have enough information about the status of groundwater in most parts of the world to enable the kind of evidence-based, informed decision-making that is central to sustainable use in the long term. 

In practical terms, this lack of information manifests as under-resourced water agencies, many of which follow now invalidated water monitoring practices resulting in the misrepresentation of the status of groundwater quality. Without accurate information about what is happening underground, hundreds of millions of people continue to consume contaminated water, either because agencies remain unaware of the presence of harmful natural contaminants, or weak regulatory regimes don’t sufficiently disincentivize polluters.  Without appropriate regulation in place, polluting activities continue apace. 

The challenge and cost of cleaning up polluted groundwater, or treating it in perpetuity, is far greater than protecting it in the first place. The intergenerational human and economic costs of these avoidable phenomena are measured in hundreds of millions of lives and hundreds of billions of dollars. Compared to these, the financial costs of groundwater quality monitoring and protection are negligible. Saving just one major abstraction from serious pollution could pay for an entire protection program. Not adopting these measures is to neglect a moral duty to future generations.  

But it doesn’t have to be this way. At the outset we made the point that there is a great deal we still don’t know about the status of groundwater resources. But here we deviate from the Dunning-Kruger Effect in that we are acutely aware of what it is we don’t know. Plus, we know a great deal about how to find out. 

The recently published Seeing the Invisible: A Strategic Report on Groundwater Quality and its companion, A Practical Manual on Groundwater Quality Monitoring, not only provides a detailed description of the types and nature of contaminants in groundwater, but also the tools and resources for its measurement and long-term monitoring, and techniques to protect it from getting contaminated in the first place. 

Our hope with this report is for decision makers to become conscious of groundwater’s connection to our health as humans and the health of our planet. We want to empower officials, budget holders, and policy makers to ask the right questions to uncover the relationships between activities above ground and their impact on water underground. To avoid a collective moral failing we must be able to investigate assumptions, challenge common perceptions, and ask ourselves, “what is it that I am missing?” That’s how we overcome the Dunning-Kruger effect. 




Lucy Lytton

Senior Water Resources Management Specialist

Peter Ravenscroft

Consultant Groundwater Expert, World Bank Water

Join the Conversation

The content of this field is kept private and will not be shown publicly
Remaining characters: 1000