There has been a reported decline in sand reserves worldwide, whilst this may not seem like an important issue initially, it is imperative to understand the many uses of sand and that the formation of it is a timely process. The process takes thousands of years as sand is the product of weathering and erosion of rocks, man-made techniques involve mechanically crushing and grinding bedrock material. Sand is essential for creating buildings, used in cement, concrete, plastering, roofing, glass and even paint, with other uses being as a physical defence barrier in sandbags, as an agent to prevent fires from spreading in labs and as asphalt laid on our roads across the world. it is estimated that for all of these uses and more that we mine around 50 billion tonnes annually. Sand mining ranges in scale as it can be as little as a group of locals with shovels in their nearby river or as a large and complex operation set up by multi-million dollar organisations from halfway across the world.
Despite the seemingly abundant deposits of sand across the world in deserts and beaches the main concern for the depletion of these deposits is that we are consuming more than the renewal rate. Another factor to consider is that not all types of sand can be used, the most desirable types are the silica and quartz types due to their unique qualities, much of the sand across the world is not suitable. For example, desert sand is much finer and rounder than desired. Whilst there are alternatives such as the method of mechanically grinding down the bedrock material, our current usage of sand remains unsustainable. When the Burj Khalifa was under construction in Dubai sand had to be imported from Australia despite being a city surrounded by sand. It seems these deposits have been exhausted to the point any further usage of them would be critical to the environment. There are numerous other instances where regions covered by sand have had to revert to importing sand due to diminished deposits.
Environmental Effects
The over-extraction of sand often leads to the collapse of the area surrounding the exploited region. In South-East-Asia the Mekong River had sand over-extracted leading to a collapse of the delta, this led to the salination of fertile lands making them infertile as the barrier holding back the seawater had deteriorated. In Africa those inhabiting coastlines often extract the sand to sell as a means of survival however this has left the coastlines vulnerable. Complied with the effects of climate change, this puts the depleted coastlines at risk. It has also been documented that extracting excessive amounts of sand can alter the way and the direction of the water passing in the body of water, which determines the movement of sediments, nutrients and many essential molecules meaning there can be a cascading effect caused by over-harvesting sand.
Sand Mafias
Another cause for concern stemming from the sand depletion crisis is the immergence of ‘sand mafias’ and cartels revolving around the mining of sand. They are very apparent in India, numerous accounts describe these cartels seizing land by force and repurposing it for sand extraction, often by cutting down crops and removing layers of soil. Despite attempts at legal action using police, laws and courts; corruption proved too great an enemy as these mafias were supposedly backed by corporations willing to do whatever it took to protect their profits.
Alternatives?
It is imperative to remember that the sand reserves are not infinite, and that over consumption could pose a larger threat than it would be to cut down on consumption. In the short term, we can cut down on consumption and exercise the mechanical alternative. This itself is another issue which only postpones our concerns as the bedrock material used in the mechanical process is what makes sand so eventually, we will run out of the material which makes sand and this makes sand renewal an impossible process, hence why it should only be used in the short term. A longer term solution is finding a sustainable and efficiently renewable material to replace or decrease the reliance on sand enough to the point where the rate of consumption is less than the rate of renewal. One material proposed was stone dust originating from the walls of gravel mines however not much research has been done on this yet. On the other hand, a material that has been developed and studied at the University of Colorado is a living bio-material with properties similar to concrete that can be grown. It works by utilising specific algae which can secrete calcium carbonate (limestone) minerals which act similarly to cement.
Final Thoughts
Whilst replacing sand for these purposes is easier said than done, we must avoid over-consumption of this resource as failure to do so will leave us vulnerable in the face of climate change as we have already seen coastlines decline and once fertile land be turned to harsh and challenging land.