“Groundwater contamination is the biggest threat to humanity,” Lee Kuan Yew Water Prize Winner and Professor John Cherry stated categorically in his address to delegates at Singapore International Water Week. “We are in the middle of a water crises. The new scarcity will shape how we live, work, what we eat.”
Groundwater accounts for about 96 percent of all freshwater, he noted, and about 50 percent of the global population depends on groundwater for drinking.
Cherry, a hydrogeology expert known for his dedication to protection of groundwater resources and his contributions to groundwater management, focused on four groundwater quality issues.
The first is groundwater contamination, which can travel a few meters a day, even in bedrock, and continues to move underground year after year. Nitrates, most often from sewage leaking out of septic systems, are the most common groundwater contaminant globally. Oily industrial contaminants, viruses from leaky sewers, and waste from agricultural processes cause the contamination, and new contaminants such as artificial sweeteners and pharmaceuticals are showing as well. Contamination is “easy to cause, lasts a long time, and is difficult to clean up,” said Cherry.
Pumping in the wrong zone, such as using wrongly positioned wells that have natural geological arsenic or fluoride, is the second cause of poor groundwater quality.
The third is pumping too much, often for food production, and for livestock-raising in particular. This results in a cone of depression, then multiple cones of depression, until the aquifer dries up. In California, for example, over-pumping for food production has caused massive losses of water in the Central Valley since the 1980s.
Pumping some aquifers has also caused land surface subsidence; Bangkok is currently sinking at a rate of 12 centimeters per year, and Mexico City dropping 28 centimeters per year.
The largest problem, though, may be in the North China Plain. “China has the largest cone of depression in the world,” Cherry said, and “the depth of water continues to go down lower.”
The final water quality issue is pumping too little, or not pumping at all. Nearly a billion people, many of them farmers in Asia, live on hard bedrock. There is a water table beneath them, so even those living on a mountainside can farm as long as they have access to that water.
Most mountain dwellers rely on seeps or springs, however, and they construct cisterns to collect spring water. Bacteria and viruses from human and animal waste then cause contamination, which in turn can cause child deaths and poor health.
The solution, Cherry said, is to drill deeper in the rock using portable drills from the mineral exploration industry.
Cherry also called for better groundwater monitoring.
He provided a somewhat unconventional solution to the groundwater contamination crisis. Noting that 80 percent of all freshwater is used for food production, which causes the most water pollution, Cherry said “eating meat is the largest single contributor to the global water crisis. Diet changes could reduce per capita water consumption in the industrialized countries by up to 40 percent.”
In closing, he reiterated his view that groundwater is at the heart of the global water crisis. The solution, he said, is “better education, understanding, monitoring, technologies, eat food better.”
Singapore International Water Week (SIWW) is a biennial event that gathers stakeholders from the global water industry to share best practices, showcase the latest technologies and tap business opportunities. This year's SIWW runs from July 10-14th.