THE COVERT GROUND-WATER CRISIS
by Someshwar Singh
Geneva, 3 Mar 2000 -- High levels of chemical-use and waste generation in recent decades are slowly poisoning supplies of groundwater - the major source of our freshwater needs. It is a silent disaster spreading through many parts of the world, warns the latest issue of the World Watch magazine.
An article by Payal Sampat, staff researcher at the WorldWatch Institute, entitled "Groundwater Shock - The Polluting of the World's Major Freshwater Stores" notes that the relentless contamination of ground-water will make the supplies of usable water tighter still.
Though water is acknowledged to be the most valuable things on earth, it's the thing most consistently overlooked, and most widely used as final resting place for our waste. The article notes that numerous studies have tracked the extent to which our increasing demand on water has made it a resource critical to a degree that even gold and oil have never been.
Worldwide, 97% of the planet's liquified freshwater is storied in aquifers.
More than a third of the planet's people live and work in densely settled cities, which occupy just 2% of the Earth's land area. With the labour force thus concentrated, factories and other centres of employment also group together the same urban areas.
Aquifers in these areas are beginning to mirror the increasing density and diversity of the human activity above them. Whereas the pollutants emanating from hog farms or copper mines may be quite predictable, the waste streams flowing into the water under the cities contain a witch's brew of contaminants.
A major factor in such contamination is that in most places people have learned to dispose of waste - to remove it from sight and smell - so effectively that it is easy to forget that the Earth is a closed ecological system in which nothing permanently disappears. The methods normally used to conceal garbage and other waste -- landfills, septic tanks, and sewers -- become the major conduits of chemical pollution of groundwater.
In the United States, businesses drain almost 2 million kilograms of assorted chemicals into septic systems each year, contaminating the drinking water of 1.3 million people. In many parts of the developing world, factories still dump their liquid effluent onto the ground and wait for it to disappear. And even protected landfills can be a potent source of aquifer pollution: the US Environment Protection Agency (EPA) found that a quarter of the landfills in the U.S. State of Maine, for example, had contaminated groundwater.
In industrial countries, waste that is too hazardous to landfill is routinely buried in underground tanks. But as these caskets age, like gasoline tanks, they eventually spring leaks. In California's Silicon Valley, where electronics industries store assorted waste solvents in underground tanks, local groundwater authorities found that 85% of the tanks they inspected had leaks.
Silicon Valley has more Superfund sites - most of them affecting groundwater - than any other area its size in the country. And 60% of the United States' liquid hazardous wastes - 34 billion litres of solvents, heavy metals, and radioactive materials - is directly injected into the ground.
Although the effluent are injected below the deepest source of drinking water, some of these wastes have entered aquifers used for water supplies in parts of Florida, Texas, Ohio, and Oklahoma.
Scores of cities in the developing world, such as Shenyang in China and Jaipur in India have had to seek out alternate supplies of water because their groundwater has become unusable. Santa Cruz, in Bolivia, has also struggled to find clean water, as its shallow aquifer that is the city's main water source has had to soak up the brew of sulphates, nitrates, and chlorides dumped over it. But as it has sunk deeper wells in pursuit of pure supplies, the effluent has travelled deeper into the aquifer to replace the water pumped out of it.
In places where alternate supplies are not easily available, utilities will have to resort to increasingly elaborated filtration set-ups to make the water safe for drinking. In heavily contaminated areas, hundreds of different filters may be necessary. At present, utilities in the U.S. Midwest spend $400 million each year to treat water for just one chemical - atrazine, the most commonly detected pesticide in the U.S. groundwater. When chemicals are found in unpredictable mixtures, rather than discreetly, providing safe water may become even more expensive.
Some of the greatest shocks, says the study, may be felt in places where chemical use and disposal has climbed in the last few decades, and where the most basic measures to shield groundwater have not been taken. In India, for example, the Central Pollution Control Board (CPCB) surveyed 22 major industrial zones and found that groundwater in everyone of them was unfit for drinking.
When asked about these findings, CPCB chairman D.K. Biswas remarked,"The result is frightening, and it is my belief that we will get more shocks in the future."
Jack Barbash, an environmental chemist at the U.S. Geological Survey, points out that we may not need to wait for expensive tests to alert us to what to expect in our groundwater. "If you want to know what you are likely to find in aquifers near Shanghai or Calcutta, just look at what's used above ground," he says. "If you've been applying DDT to a field for 20 years, for example, that's one of the chemicals you're likely to find in the underlying groundwater."
Unlike rivers, the pollution in aquifers is generally irreversible. The rate of ground-water renewal is very slow in comparison with that of surface water. While it is true that some aquifers recharge fairly quickly, the average recycling time for groundwater is estimated at 1,400 years, as opposed to only 20 days for river water. And because water in aquifers moves through the Earth with glacial slowness, its pollutants continue to accumulate. Unlike rivers, which flush themselves into the oceans, aquifers become sinks for pollution.
"Just as the advent of the climate change has awakened us to the fact that the air over our heads is an arena of enormous forces in the midst of titanic shifts, the water crisis has revealed that, slow-moving though it may be, ground-water is part of a system of powerful hydrological interactions - between earth, surface water, sky and sea -that we ignore at our peril," says the study.
Over the centuries, as populations and cropland expanded, innovative well-digging techniques evolved in China, India, and Europe. Water became such a valuable resources that some cultures developed elaborate mythologies imbuing underground water and its seekers with special powers. In medieval Europe, people called water witches or dowsers were believed to be able to detect groundwater using a forked stick and mystical insight.
Today, major aquifers are tapped on every continent, and ground-water is the primary source of drinking water for more than 1.5 billion people worldwide. The aquifer that lies beneath the Huang-Huai-Hai plain in eastern China alone supplies drinking water to nearly 160 million people. Asia as a whole relies on its ground-water for nearly one-third of its drinking water supply. Some of the largest cities in the developing world - Jakarta, Dhaka, Lima, and Mexico City, among them - depend on aquifers for almost all their water. And in rural areas, where centralised water supply systems are undeveloped, groundwater is typically the source of water. More than 95% of the rural U.S. populations depends on groundwater for drinking.
Worldwide, irrigation is by far the biggest drain on freshwater: it accounts for about 70% of the water drawn from rivers and wells each year. Since 1950, there has been a dramatic expansion in irrigated agriculture. In India, the leading country in total irrigated area and the world's third largest grain producer, the number of shallow tubewells used to draw groundwater surged from 3,000 in 1960 to 6 million in 1990. While India doubled the amount of its land irrigated by surface water between 1950 and 1985, it increased the area watered by aquifers 113-fold.
Today, aquifers supply water to more than half of India's irrigated land. The United States, with the third highest irrigated areas in the world, used groundwater for 43% of its irrigated farmland.
Other industries have been expanding their water use even faster than agriculture - and generating much higher profits in the process. On average, a ton of water used in industry generates roughly $14,000 worth of output - about 70 times as much profit as the same amount of water used to grow grain. Thus as the world has industrialised, substantial mounts of water have been shifted from farms to more lucrative factories. Industry's share of total consumption has reached 19% and is likely to continue rising rapidly. The amount of water available for drinking is thus constrained not only by a limited resource base, but by competition with other, more powerful users.
On almost every continent, many major aquifers are being drained faster than their natural rate of recharge. Groundwater depletion is most severe in parts of India, China, the USA, North Africa, and the Middle East.
As the competition among factories, farms, and household intensifies, it's easy to overlook the extent to which freshwater is also required for essential ecological services. It is not just rainfall, but groundwater welling from beneath, that replenished rivers, lakes and streams. In a study of 54 streams in different parts of the country, the U.S. geological Survey has found groundwater is the source for more than half the flow, on an average.
Groundwater provides the base contribution to for the Mississippi, the Niger, the Yangtze, and many more of the world's great rivers - some of which would otherwise not be flowing year-round. Wetlands, important habitats for birds, fish, and other wildlife, are often largely groundwater-fed, created in places where the water table overflows to the surface on a constant basis.
And while providing surface bodies with enough water to keep them stable, aquifers also help prevent them from flooding: when it rains heavily, aquifers beneath rivers soak up the excess water, preventing the surface flow from rising too rapidly and overflowing onto neighbouring fields and towns.
In tropical Asia, where the hot season can last as long as 9 months, and where monsoon rains can be very intense, this dual hydrological service is of critical value.
Patchwork response will not be effective, as solutions, the study suggests. "Given how much damage this pollution inflicts on public health, the environment, and the economy once it gets into the water, it's critical that emphasis be shifted from filtering out toxins to not using them in the first place.
Andrew Skinner, who heads the International Association of Hydrogeologists, puts it this way: "Prevention is the only credible strategy."
This requires looking not just at individual factories, gas stations, cornfield, and dry-cleaning plants, but at the whole social, industrial and agricultural systems of which these businesses are a part. The ecological untenability of these systems is what's really poisoning the world's water. It is the predominant system of high-input agriculture, for example, that not only shrinks biodiversity with its vast monocultures, but also overwhelms the land - and the underlying water - with its massive applications of agricultural chemicals. It's the system of car-dominated, geographically expanding cities that not only generates unsustainable amounts of climate-disrupting greenhouse gases and acid-rain causing air pollution, but also overwhelms aquifers and soils with petrochemicals, heavy metals, and sewage. An adequate response will require a thorough overhaul of each of these systems.
"To save water in time requires the same fundamental restructuring of the global economy as does the stabilisation of the climate and biosphere as a whole - the rapid transition from a resource-depleting, oil and coal-fuelled, high-input industrial and agricultural economy to one that is based on renewable energy, compact cities, and a very light human footprint," the study suggests. "We've been slow to come to grips with this, but it may be our thirst that finally makes us act."
The study also stresses the advantages of traditional manure and legume- based cropping systems which use no synthetic fertiliser or pesticides and in the industrial settings, the building of "closed loop" production and consumption systems which can help slash the quantities of waste that factories and cities send to landfills, sewers, and dumps - thus protecting aquifers from leaking pollutants. (SUNS4620)
The above article first appeared in the South-North Development Monitor (SUNS) .
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