By far the largest mining endeavor globally is digging up sand, mainly for the concrete that goes into buildings. But this little-noticed and largely unregulated activity has serious costs — damaging rivers, wreaking havoc on coastal ecosystems, and even wiping away entire islands.

Nothing sounds so dull — even for most environmentalists — as sand mining. But in India, reports of sand mafias cashing in on the country’s construction boom have lately been making headlines. Last month, the issue went viral — a 17-year-old girl named Kavya in a fishing village in the state of Kerala posted a video on a mobile phone app about how excavators and dredgers had invaded her coastal community. “The land beneath our feet is sinking away,” she said. It became a sensation across the country. Bollywood actors backed her, and now the country’s National Green Tribunal, a government body aimed at settling environmental disputes, is to consider the case. Sand mining is the world’s largest mining endeavor, responsible for 85 percent of all mineral extraction. It is also the least regulated, and quite possibly the most corrupt and environmentally destructive. So could this be a turning point? In recent years, as I have traveled the world looking at environmental issues, sand mining has kept appearing out of the corner of my eye. Always there, but rarely the main story. While in Kerala in August, researching the environmental factors behind recent floods, I found that sand is dredged from local rivers 40 times faster than the rivers can replace it. Riverbeds have been lowered by around 6 feet as a result. A month later, in Ethiopia’s Rift Valley, while visiting the Abijatta-Shalla National Park, I watched as trucks drove into the park and loaded up with sand destined for building sites in Addis Ababa, 100 miles away. It was illegal, but park officials shrugged their shoulders.

China is estimated to consume more sand in three years than the U.S. consumed in the entire 20th century.

In Cambodia, researching land grabs in the western province of Koh Kong, I drove past three local estuaries where dredgers, organized by real estate tycoon and politician Ly Yong Phat, were extracting vast amounts of sand for land reclamation projects in faraway Singapore. Sand mining concessions in national parks and internationally recognized wetlands were killing mangroves and sea grasses that were home to Irrawaddy dolphins, green turtles, and hairy-nosed otters, one of the world’s rarest mammals. Sand and gravel are mined on a huge scale around the world. But few global data are collected on this activity. The United Nations Environment Program (UNEP) estimated that the total exceeds 40 billion tons a year. But its estimate had to be based on a proxy: cement manufacture. Every ton of cement requires six to seven tons of sand and gravel to make concrete. Concrete is the predominant use for sand. But sand also makes up 90 percent of asphalt on roads. It also is used for land reclamation in places like Singapore. And it is widely used in industries such as glass manufacturing and fracking, where it forms part of the gritty mixture injected underground to fracture shale deposits and release natural gas or oil. Around 60 percent of sand use worldwide is in China, which is estimated to consume more sand in three years than the U.S. consumed in the entire 20th century. Yet despite the vast scale, ubiquity, and environmental footprint of sand mining, licensing is often delegated to local authorities; environmental impact assessments are rare; laws are routinely flouted; and there are no global treaties governing its extraction, use or trade, or even to promote good practice. Not all sand is the same. Some is refined to extract high concentrations of rare earths or metals. I reported here two years ago on the assassination of an environmental and community activist in South Africa’s Eastern Cape, who was fighting plans by an Australian company to excavate local sand dunes for titanium.

Trucks load illegally mined sea sand along beaches north of Dakar to supply Senegal's construction industry. SEYLLOU/AFP/Getty Images

But even regular sand is not suitable for all uses. Desert sand, for instance, is mostly useless for construction, because its grains have usually been rounded by wind erosion and do not bind well in concrete. Miners mostly target sand dug from pits on land, dredged from riverbeds, or scooped up from the seabed. Marine sand is less good for concrete, however, because it has to be washed clean of salt that could otherwise corrode metal in structural building reinforcements. That makes river sand the source of first resort — even though mining it is, according to the environmental group WWF, usually the most environmentally destructive. Typically, floating platforms employ buckets on conveyor belts to gouge sand from riverbeds. Such crude methods, though cheap, can drastically alter river flow, erode riverbanks, dry up tributaries, lower water tables, and trash wetlands and fisheries. The impacts are made worse, says UNEP researcher Pascal Peduzzi, because “a lack of proper scientific methodology for river sand mining has led to indiscriminate sand mining, while weak governance and corruption have led to widespread illegal mining.”

Rivers will attempt to fill in the holes dug out by sand miners, but with twice as much sand estimated to be taken from the world’s rivers as natural processes of sedimentation can restore, they will rarely do it fast enough to undo the damage. Researchers have spoken of a “looming tragedy of the sand commons.” Take what WWF calls “the largest sand mine in the world”: Lake Poyang on the Yangtze River in China. For many years, sand from the main stem of the Yangtze was dredged to build the megacity of Shanghai downstream, which has erected more skyscrapers in the last decade than New York. That practice was stopped in 2000 because the floating platforms were blocking the river. But the miners simply moved from the river itself to Lake Poyang in the Yangtze’s floodplain. China’s largest lake is also Asia’s largest winter stopover for migrating birds, including 90 percent of the world’s endangered population of Siberian cranes. By 2006, the last published estimate, dredgers were annually removing more than 400 million tons of sand, mostly from the waterway that links the lake to the Yangtze.

Satellite images from 1995 and 2013 show the impact of sand mining on the waterway connecting China's Poyang Lake and the Yangtze River. NASA Earth Observatory

By removing so much sand, the miners have almost doubled the waterway’s capacity, partially draining the lake and making it more vulnerable to drought. Researchers also blame the mining for reducing lake fisheries and for a catastrophic decline in the number of finless porpoises in the main river. Xijun Lai of the Chinese Academy of Science in Nanjing called for a ban on sand mining in the lake. Equally disturbing is the situation on the Mekong River in Vietnam and Cambodia. Jean-Paul Bravard of the University of Lyon, in a detailed study for WWF, found around 55 million tons of sand was extracted from the lower reaches of the river each year, almost double the input from upstream. The Stockholm Environment Institute concluded that the mining lowered river levels by more than 3 feet, while contributing to both coastal erosion and an invasion of saltwater into the delta, where it was poisoning rice fields. Ironically, much of the sand was being used to maintain coastal defenses and raise delta roads above flood levels. The mining could also undermine Mekong river fisheries, which directly feed more than 60 million people, says hydrologist Lois Koehnken. The biggest concern, she wrote in a study for WWF, is dredging on the river near the fast-growing Cambodian capital Phnom Penh, where a vital tributary called the Tonle Sap joins the main river. Much of the Mekong’s fish stock originates in marshland at the head of the Tonle Sap. Fish breed there and return to the main river during the monsoon season, when the swollen Mekong bursts its banks and forces the Tonle Sap to flow in reverse. Dredging could increase the main river’s capacity sufficiently to halt this reverse flow, which would dry up the fish breeding grounds.

Singapore has created an extra 50 square miles of land thanks to 500 million tons of imported sand.

River and beach mining have been largely banished in developed countries, although not entirely. America’s last beach mine is in Monterey, California. It extracts as much as half a million tons of sand a year. The controversial operation is due to shut next year, under a deal with the state authorities. There is also a push in Houston to halt sand mining on the banks of the San Jacinto River, which is alleged to have caused sedimentation that played a part in flooding during Hurricane Harvey in 2017. But sand mining in rivers and on beaches continues to expand in many developing countries. It is often a lawless business, beset by corruption and violence. In India, the world’s second-largest sand mining country, widespread illegal extraction “occurs through the country… run by highly organized and often violent sand mafias,” reported Koehnken. Rogue operators routinely bribe officials, and even the courts prove powerless. A policeman was crushed to death by a tractor while trying to halt illegal mining in a national sanctuary for the Indian crocodile, the gharial, in Madhya Pradesh. Violent gangs protect sand miners around Nairobi in Kenya. Malaysian officials have been charged with turning a blind eye to smuggling in a “sex-for-sand” scandal. There have been beach battles over sand from Java to Jamaica. In some countries, miners are heading offshore. But in estuaries and close inshore, the ecosystem damage may be as great as in rivers. Dredging destroys sea grasses, creates plumes of sediment that can drift for miles, and may trigger coastal erosion. In the low-lying Indian Ocean archipelago of the Maldives, sea defenses for the capital Male are being reinforced using sand dug from offshore sand islands, thus “paradoxically… increasing the need to relocate their populations,” UNEP’s Peduzzi notes.

Laborers transport sand from the Yamuna River in India, where a construction boom has led to indiscriminate mining of river sand. AP Photo/Rajesh Kumar Singh

So there are moves to take the dredgers further out to sea. Britain, for instance, now gets up to a quarter of its sand from the sea floor. It dredges up to 10 million tons, much of it from sand banks off East Anglia in the North Sea, a region where there has been concern that the loss of sediment accelerates rampant coastal erosion, as well as damaging sea-bed communities such as crabs and starfish. Much offshore sand is used for land reclamation projects, where the risks of salt causing corrosion do not usually matter. Most notoriously, Singapore has created an extra 50 square miles of land, growing its size by 20 percent, thanks to more than half-a-billion tons of imported sand. Much of that sand has come from Indonesia, where at least 24 small islands have reportedly been removed from the map as a result, and from Cambodia, where sand miner Ly Yong Phat sent large quantities of sand to Singapore before the Cambodian government shut down the trade in 2016. Land reclamation is a craze in coastal Asia, from Penang Island in Malaysia to New Manila Bay in the Philippines. Dubai’s construction of extravagant artificial islands, earmarked for real estate investment, has soaked up more than 750 million tons. When they ran out of marine sand, the island builders imported from Australia – a strange case of sending sand to Arabia. China’s coastal cities, meanwhile, are said to have been reclaiming enough land from the ocean to make a new Singapore every year. Projects include Nanhui New City outside Shanghai, and Cafofeidian in Bohai Bay, which has been promoted as an eco-city development. China also dumps sand on reefs in the South China Sea to create islands as part of its territorial claim to the surrounding sea.

A simple rule is that sand mining in rivers should not exceed the rate of resupply of sand from upstream.

What should be done? Technically, some options exist. An untapped source of sand is the material that accumulates on the bottom of reservoirs. It could be dredged or flushed out. There is a win/win here. Dam operators would get the benefit of extra capacity for water storage, though arguably the sand should really be put back into the rivers it came from, rather than diverted for construction. In developed countries, where new construction often replaces demolished buildings, there is untapped potential to recycle building rubble instead of using new concrete. A third of construction material for housing in the UK is already recycled. Glass recycling reduces that industry’s need for new sand. And there are substitutes for sand in concrete manufacture, including ash from power station incinerators, and dust from stone quarries. The problem is that at less than $10 a ton, sand remains very cheap.