News of a sand shortage has been floating around for the past few years, but are we really running out of sand?
Sand is a natural resource that you’d think would be renewable, but it takes millions of years to erode a rock into sand. It’s not as easy or eco-friendly to produce sand mechanically either.
Is sand environmentally friendly?
The earth is full of sand, which is divided into different types.
It’s used primarily for construction – in concrete, asphalt, glass, and more. In fact, sand is the third most used resource after air and water.
Sand itself is naturally occurring, formed from the erosion of rocks. This means there are many different types of sand depending on its composition.
Most sand is made with silica, also known as silicon dioxide, from quartz. Silica is present in regular construction sand as well as ‘silica sand’, which is used in glassmaking due to comprising at least 95% silica.
Regular sand contains other materials such as iron oxide, carbonate, potassium, and other materials.
We’re familiar with regular sand in our beaches, but what many don’t realize is how different it is to desert sand.
I’ve wondered myself why we can’t import desert sand to help rebuild beaches for eroding coastal areas (without considering the emissions from transporting it all).
Desert and ocean sand have different compositions due to their environments.
Because desert sand is so small and smooth, using it in concrete would make the concrete weaker and more prone to breaking apart. Sand from deeper layers underwater has salt mixed in, which absorbs moisture and would cause dampness.
While this naturally-occurring sand is perfect for its original environment, the use of sand in construction isn’t as environmentally friendly. It has to be processed.
For use in construction, sand first needs to be extracted and transported to a processing center. While most processing centers are built near sand deposits, this means as much sand as possible is removed from the deposit instead of taking smaller amounts from a wider area. The extraction of this sand can happen over decades.
Some processing centers are mobile and can be taken to quarries, though this is usually used only for remote places.
Once in the processing center, the sand must first be sorted to remove rocks, clay, sticks, and other materials. Then the sand is sorted according to the size of its granules. Any remaining clay or soil is removed by washing the sand before it makes its way to be stored.
However, sometimes sand first has to undergo crushing to make the right size particles, which may not be naturally occurring.
Is sand a sustainable material?
A sustainable material is a material that can be produced in required volumes without depleting or disrupting environments and resource systems.
Around “50 billion tons of construction-grade sand is needed each year“, resulting in a demand for sand that is clearly unsustainable.
Sand dredging and mining have ruined natural environments and ecosystems, and many European countries export ocean sand which has hurt fisheries and their local ecosystems.
Sand is also often sent to landfill as concrete, glass, and other processed sand materials instead of being recycled.
Is sand renewable and sustainable?
Because sand isn’t sustainably sourced, it isn’t considered a sustainable material.
Sand is technically renewable, however, because it takes millions of years to naturally produce sand it’s not considered renewable.
Coastal geologist Richard Parkinson says that “when sand is eroded from the beach during a storm, it typically accumulates in offshore areas as a very thin layer”. This makes it harder to rebuild coastal areas because the sand can’t be dredged easily from the same area.
This can lead to sand shortages in areas, which drives up the price of sand.
We may have an abundance of sand but it won’t last forever, especially in the quality we need for construction.
Is sand a finite resource?
It’s not known exactly how much sand is on the planet, but we have to remember that construction, especially for concrete and glass, requires specific types of sand.
Ruling out desert sand and the majority of ocean sand leaves us with only what we can extract from the ground itself. This requires increasing sand mining operations across continents, which can drastically change landscapes, destroy ecosystems, and cause environmental damage on a massive scale.
Because of this, it’s safe to assume that sand is a finite resource. We can try to produce it by grinding rocks mechanically to speed up the natural erosion process, but this isn’t eco-friendly or more sustainable.
It’s why we should be aiming to recycle and reuse sand as much as possible.
The impact of sand mining on the environment
Most sand mining operations excavate sand from riverbeds and coastal areas, though it is also removed from inland sand deposits. Sand dredging ships can collect up to 100,000 tons of ocean sand a day.
Sand mining in riverbeds and along coastal areas is known to cause rivers and estuaries to deepen and river mouths and coastal inlets to enlarge. This changes the structure of the environment and disrupts the local ecosystem.
Bed degradation, bed coarsening, lowered water tables near the streambed, and channel instability are all impacts of large changes in the local environment, which affect wildlife and plants that depend on the river. This includes aquatic ecosystems, wetland ecosystems, and more.
In excess, sand mining can threaten infrastructure such as bridges, roads, and the surrounding riverbanks.
It also increases vehicle traffic and emissions during mining operations.
Does sand mining cause erosion?
Removing sand from rivers causes erosion and shrinkage of riverbanks, as well as erosion of beaches.
Rivers naturally carry sediment from the riverbed down to the river mouth, depositing sediment at the coast which forms beaches.
Erosion of riverbanks can also cause infrastructure – such as bridges, buildings, farmland, roads, and dikes – to become unstable or damaged.
Sand mining operations need to be aware of the ‘sand budget’ – the amount of sand that can be removed without causing unsustainable erosion or degradation. This doesn’t just affect the location of the mining, but also upstream and downstream areas.
How does sand mining destroy the environment?
Sand mining in rivers can destroy the environment by:
- Depleting or drastically changing habitats, resulting in less biodiversity.
- Endangering species that rely on their natural habitat conditions by disrupting or destroying parts of the habitat.
- Removing or destroying vegetation within aquatic ecosystems.
- Widening rivers, which leads to shallow streambeds resulting in the obstruction of aquatic migration.
- Reducing water quality by disrupting a river’s natural flow, dumping organic matter or garbage, leaking oil or chemicals from machinery, and introducing saltwater into freshwater in coastal areas.
- Smothering fisheries by kicking up underlying sediment.
- Accelerating riverbank and coastal erosion.
- Increasing the risk of flooding by reshaping riverbanks or coastal defenses.
How can sand mining be more sustainable?
The United Nations Environmental Programme recommends the following measures for sustainable sand usage:
- Avoiding unnecessary natural sand consumption
- Using alternative materials
- Reducing sand extraction impacts with existing standards and best practices
Avoiding unnecessary natural sand consumption relies largely on reducing the amount of sand we use, but it calls for understanding our reliance on sand and looking for renewable resources.
It also requires making consumption practices more efficient, by making the most of the sand. Proper maintenance and repurposing of old buildings and infrastructure will use less sand than demolishing and building new in the same area.
Increasing the amount of recycled sand used and replacing some usage with renewable alternatives can help us slow the rate of sand required to be extracted each year.
Other alternative materials include recycling asphalt waste and substituting sand for waste by-products like fly ash.
Reducing the impact of sand mining largely depends on regulations and the enforcement of those regulations.
Promoting sustainable mining operations has to be enforced to have any effect, and it also needs to take into account ecological, geological, and hydrological impacts on an environment.