The Unsustainable Use of Sand: Reporting on a Global Problem

: Sand is considered one of the most consumed natural resource, being essential to many industries, including building construction, electronics, plastics, and water ﬁltration. This paper assesses the environmental impact of sand extraction and the problems associated with its illegal exploitation. The analysis indicates that extracting sand at a greater rate than that at which it is naturally replenished has adverse consequences for fauna and ﬂora. Further, illicit mining activities compound environmental damages and result in conﬂict, the loss of taxes/royalties, illegal work, and losses in the tourism industry. As sea-level rise associated with climate change threatens coastal areas, sand in coastal areas will play an increasingly greater role in determining the amount of damage from ﬂoods and erosion. The present analysis points to the need for swift action to regulate sand mining, monitoring, law enforcement, and international cooperation.


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The world is facing a global sand crisis • Negative environmental impacts of excessive sand exploitation are multiple • Uncontrolled expansion of illegal sand mining: causes and consequences

Sand: A Valuable Natural Resource
Sand consumption has increased worldwide, in part due to the growth of the world s population, increasing standards of living, and rapid urban expansion [1,2]. Sand is used in a wide range of industries and products [3], including water filtration, plastics, and the electronics sector [1]. In fact, almost every house, dam, road, wine glass, and cellphone contains some type of sand-related material [4]. Vast quantities of frack sand are used to extract oil from shale in the fracking industry. As a result of this trend, the United Nations Environment Programme considers that sand has become one of the most consumed natural resources at present [4]. A UNEP report estimates that sand and gravel account for up to 85% of the weight of minerals mined globally each year [5].
Sand refers to loose granular materials that are produced as a result of the disintegration of rocks. It is used as a major component for producing concrete and building materials, asphalt, and glass [1,6]. Whereas sand from beaches and rivers is commonly Sand refers to loose granular materials that are produced as a result of the disintegration of rocks. It is used as a major component for producing concrete and building materials, asphalt, and glass [1,6]. Whereas sand from beaches and rivers is commonly used for the construction sector, desert sand is typically too fine or too smooth to bind building materials.
Almost every country is dependent on sand imports (see Figure 1), including those where sand mining activities occur. This is due, in part, to sand supplies being unevenly distributed within and across counties and the differing requirements for the type of sand used in various industries. Sand is an increasingly valuable commodity and is essential to the economies of countries around the world. Many industries depend on sand as an essential resource in the production of various products. The sand mining industry contributes to job creation and investments in mining areas and sand exportation promotes economic growth. In short, the sand industry provides economic benefits to countries producing and importing sand. Sand and gravel production is dominated by the United States, Netherlands, Spain, Turkey, and India (Table 1). Among the countries that import the greatest amounts mention can be made of Canada, China, Belgium, Luxembourg, Singapore, and Germany [8]. Source: Modified from Garside (2020) [9] In 2018, European countries were among the leading exporters, along with North America and Asia ( Figure 2). Sand is an increasingly valuable commodity and is essential to the economies of countries around the world. Many industries depend on sand as an essential resource in the production of various products. The sand mining industry contributes to job creation and investments in mining areas and sand exportation promotes economic growth. In short, the sand industry provides economic benefits to countries producing and importing sand. Sand and gravel production is dominated by the United States, Netherlands, Spain, Turkey, and India (Table 1). Among the countries that import the greatest amounts mention can be made of Canada, China, Belgium, Luxembourg, Singapore, and Germany [8]. In 2018, European countries were among the leading exporters, along with North America and Asia ( Figure 2).  Unfortunately, the extensive use of sand and the increase in mining activities have negative environmental impacts on both the local and global levels [10], and urgent measures are needed to limit these effects. The environmental consequences vary, in part, depending on where sand is mined and sourced. Three main natural sand sources include pit sand, river sand, and sea sand [11]. To compound the environmental consequences of legal mining and sourcing, illegal activities associated with sand mining and its transportation have been reported in many parts of the world. They most commonly occur in underdeveloped and developing nations [5].
This paper assesses the environmental impacts of sand exploitation and the problems associated with the illegal exploitation of this essential resource.

Methodology
To identify the extent to which environmental problems are associated with legal and illicit sand exploitation, we reviewed and analyzed a wide range of literature on the topic, including peer-reviewed literature, UN reports, and statistical documents (see Table 2) while considering the following aspects: (a) The current degree of sand usage and exploitation across a sample of countries. This analysis was performed in order to obtain an overview of sand consumption across a set of countries, including the amount of sand being explored for future development and use. (b) The environmental impacts of sand mining and use. The analysis focused on anticipated and potential impacts of sand use, especially on the physical environment. (c) The degree to which illegal activities are associated with sand exploitation, including the causes, consequences, and measures needed to combat this phenomenon.
The innovation of this approach is that it focuses not only on sand exploitation in quantitative terms but also classifies countries according to the amounts of sand they use. The analysis also considers illicit mining activities. The assessment of environmental impacts includes determining the physical impacts as well as the consequences on fauna and flora. Unfortunately, the extensive use of sand and the increase in mining activities have negative environmental impacts on both the local and global levels [10], and urgent measures are needed to limit these effects. The environmental consequences vary, in part, depending on where sand is mined and sourced. Three main natural sand sources include pit sand, river sand, and sea sand [11]. To compound the environmental consequences of legal mining and sourcing, illegal activities associated with sand mining and its transportation have been reported in many parts of the world. They most commonly occur in underdeveloped and developing nations [5].
This paper assesses the environmental impacts of sand exploitation and the problems associated with the illegal exploitation of this essential resource.

Methodology
To identify the extent to which environmental problems are associated with legal and illicit sand exploitation, we reviewed and analyzed a wide range of literature on the topic, including peer-reviewed literature, UN reports, and statistical documents (see Table 2) while considering the following aspects: (a) The current degree of sand usage and exploitation across a sample of countries. This analysis was performed in order to obtain an overview of sand consumption across a set of countries, including the amount of sand being explored for future development and use. (b) The environmental impacts of sand mining and use. The analysis focused on anticipated and potential impacts of sand use, especially on the physical environment. (c) The degree to which illegal activities are associated with sand exploitation, including the causes, consequences, and measures needed to combat this phenomenon. Table 2. Some recent studies on sand mine and their sustainability impacts.

Paper/Title Focus Authors
Impact of sand mining on alluvial channel flow characteristics Physical impacts of sand mining [12] Time is running out for sand General impacts of sand exploitation [13] Sand mining on North Stradbroke Island: an Islander view of the rehabilitation of the lands Views on sand mining from indigenous people from Queensland/Australia [14] Detection of illicit sand mining and the associated environmental effects in China's fourth largest freshwater lake using daytime and nighttime satellite images Aquatic environmental effects of illegal sand dredging Lake Hongze/China [15] Regulatory and policy implications of sand mining along shallow waters of Njelele River in South Africa Exploration of regulatory and policy implications of sand mining operations in Njelele River (South Africa) [16] River bank instability from unsustainable sand mining in the lower Mekong River Analysis of current sand extraction rates versus annual sediment load in Mekong River [17] Public perspective on the environmental impacts of sea sand mining: Evidence from a choice experiment in South Korea Interviews and quantitative analysis regarding environmental impacts of the sea sand mining project in South Korean EEZ [18] Impacts of riverine sand mining on freshwater ecosystems: A review of the scientific evidence and guidance for future research Literature review on ecological impacts [19] Inventory of Estuarine and Lagoonal Ecosystems Subjected to Sand-Mining Activities in Southern Benin (West Africa) Inventory of ecosystems and of potentially affected sites [20] Impact of Sand Mining on Zooplankton of River Ganga in and Around Patna, Bihar, India Effects of sand mining on the reduction of species diversity and abundance of zooplankton In Ganga River (India) [21] The innovation of this approach is that it focuses not only on sand exploitation in quantitative terms but also classifies countries according to the amounts of sand they use. The analysis also considers illicit mining activities. The assessment of environmental impacts includes determining the physical impacts as well as the consequences on fauna and flora.

Results and Discussion
Demand for sand is increasing non-linearly, particularly in Asia and especially for concrete production. China used more sand for concrete production in 2011 and 2013 than the United States used during the entire 20th century [5]. The scale of the problem can be better assessed if one considers the fact that that one ton of cement can require up to 10 ton of sand to make concrete.
In 2018, China and India accounted for more than 60% of global cement production, with China producing more than all other countries combined [22].
Interestingly, small countries like Singapore (which largely uses sand for land reclamation) account for a significant share of sand imports. Singapore's proportion of sand imports ranged between 2.3% and 14% from 1995 to 2017 [23]. To accommodate increased global demand, there are new pressures to mine greater quantities of sand and to find alternative substitutes. Finding substitutes may take on greater importance if the rate of sand use exceeds its renewability rate [24,25].

Overview of Sand Mining Activities
Asia now has the highest level of sand mining [4,15,26,27]. Figure 3 shows some examples of sand mining levels around the world.

Overview of Sand Mining Activities
Asia now has the highest level of sand mining [4,[26][27][28]. Figure 3 shows some examples of sand mining levels around the world.   Table 3 presents some of the main legal and illegal sand mining activities worldwide, according to the available information and our analysis (sources presented in Table 3). The table presents the mine or region name, country, whether the activity is legal or illegal and in operation, and a description of the mine. The relevant literature quoted under "description of mine" is cited in the column "References". In some cases, no specific data is available (marked as n/a). Most of the sand mining activities started in the 20th century and have remained operating until the present day. Out of the 20 sand mines reported, six involve illegal activities. However, this situation is more complex to track and control.   Table 3 presents some of the main legal and illegal sand mining activities worldwide, according to the available information and our analysis (sources presented in Table 3). The table presents the mine or region name, country, whether the activity is legal or illegal and in operation, and a description of the mine. The relevant literature quoted under "description of mine" is cited in the column "References". In some cases, no specific data is available (marked as n/a). Most of the sand mining activities started in the 20th century and have remained operating until the present day. Out of the 20 sand mines reported, six involve illegal activities. However, this situation is more complex to track and control. Over-extraction of sand has led to salinization of the drinking water supply, collapse of river banks, and loss of valuable riparian land. It is estimated that the mining of sand has increased three-fold when compared to 1997. [44] Sustainability 2021, 13  Substantial amounts of sand were mined directly from the shoreline until it was hypothesized that sand mining was a significant contributor to shoreline erosion. An estimated 6.3 million cubic meters of sand were mined before it ceased in 1990. [45] Amite River-Louisiana United States Legal Use in the US Operational 1930 Open At the disturbed floodplain and channel, the combined gravel and sand extraction has exceeded 10 million tons per year. Large disturbances on the Amite River have become much more common due to a steady increase in mining activity in this area. Production reached a peak in the early to mid-1980s. The process of sand mining has accelerated coastal environmental degradation to an alarming rate in many areas. The main effects of uncontrolled sand mining include loss of land (19.2%), destruction of the beach (18.2%), destruction of the road (16.5%), land conflict (13.7%), loss of vegetation (12.2%), destruction of property (11.8%), and use of child labor (8.4%). [49] Kazan Plain Turkey Legal Use in Turkey  Closed  1980  2006 Because of the large and deep excavations by the sand-gravel pits, the aquifer has thinned and has been removed entirely in some places. There are serious unfavorable impacts on the groundwater system caused by the sand-gravel pits that operate generally below the water table with excessive extraction [50] Lake Tana Ethiopia Legal Use in Ethiopia Operational 1992 Open The ecology of the mined rivers was seriously affected by sand mining, which interfered with migratory routes of fishes and resulted in the loss of their spawning grounds. [51] Pantai Labu Indonesia Legal Mostly used in Indonesia Operational 2008 Open The impact of marine sand mining results in environmental damage (degradation) of the coast, such as abrasion and decreased productivity of marine fisheries due to declining water quality. The declines in seawater quality are especially in TSS (Total Suspended Solid) parameters. [52] Sustainability 2021, 13, 3356 8 of 16

Causes and Consequences of Illegal Sand Mining
Illegal sand mining activities are increasing worldwide and negatively impacting terrestrial, riverine, and marine environments [53] and are associated with adverse social and socioeconomic consequences. There are numerous causes of illegal mining activities, including: motivation for financial profit, -increasing global sand demand, -lack of monitoring and control systems, -relaxed policies and procedures that allow individuals and businesses to acquire mining titles for sand mining exploration, to self-monitor production, and to displace community members from mining areas, -lack of monitoring of sand extraction volume, -mining taxes and royalties are paid by the mine owner/operator based on the extracted sand volume, and acts of evasion of payment may occur in tandem with illegal activities, -poverty, low level of education, and lack of information about negative consequences of illegal mining, -deficiencies in fulfilment of technical specifications for sand extraction.
Furthermore, areas that are forbidden and restricted for mining activities are sometimes not defined properly, which may make illegal exploitation easier.
The present review of the literature indicates that there is limited research related to the consequences of illegal mining activities for some specific countries. However, Table 4 presents some of the negative consequences that are associated with illegal mining, based on the available literature. Table 4. Some of the negative consequences of illegal sand mining.

Negative Consequences References Country/Region
Environmental damages [54][55][56][57][58][59] India [60] Zimbabwe [61] Indonesia [62] Botswana [63] South Africa [64] Lower Mekong River [65] Greece This analysis underscores the need for developing, adopting, and enforcing measures and laws to limit and prevent illegal actions related to sand exploration at the local, regional, and national levels in each country involved in this activity.
A legal framework to regulate mining activities requires cooperation amongst all the sectors and stakeholders involved, appropriate regulation, monitoring, and enforcement, and efficient control systems. Reasons for illegal activities in developing and developed countries may differ. In order to reduce or prevent illegal sand mining in developing countries, it is important to consider the need for related programs, including the following: Sustainability 2021, 13, 3356 9 of 16 -governments must develop, adopt, and promote effective strategies for poverty and unemployment reduction; -develop, adopt, and implement unified strategies to address various aspects of sustainable development and environment protection, including creating mechanisms to evaluate the possibility of ecological disasters resulting from excessive illegal sand exploitation, as well as educating the public; -impose efficient and fair taxes/royalties for sand mining license holders in order to stimulate legal activities and to discourage illegal mining; -enact and enforce laws at the local, regional, and national levels to regulate the mining sector, including consequences for non-compliance (e.g., meaningful sanctions and penalties).

Environmental Impacts of Sand Mining
The very high volume of sand being currently extracted is having a serious negative impact on rivers, deltas, and coastal and marine ecosystems, such as loss of land through river or coastal erosion, the lowering of water levels, and decreases in the amount of sediment supply [69,70], and is affecting the economic and social development as well [2]. The scope of these adverse effects extends from the local area to larger regions that are far away from the sites where sand is taken [1]. For example, mining in China's Poyang Lake-which the United Nations Environment Programme believes to be the world's largest sand-extraction site-is thought to have lowered the water levels in that region [5].
Because sand is being extracted at a far greater rate than that at which it is naturally replenished, the depletion of existing sand reserves is damaging fauna and flora at significant levels. Table 5 presents some of the main environmental impacts associated with sand exploitation.  [83] Reduced integrity of coastlines with lower capacity to handle stormy weather [88] Changes to landscape [56,83] Water Channel incision [19,87,89,90] Channel widening [19,[91][92][93] Channel erosion and instability [5,93,94] Waterway siltation [73] Increased water turbidity [73] Change of river flow pattern [95] Deterioration of water quality (including groundwater) [56,73,93] Deepening of the water depths [86] Saltwater movement upstream [64,86] Changes in tidal level, range, and duration [86] Air Dust pollution [56,83,96,97] Noise and vibration [83,96,97] Table 5 highlights the serious and irreversible damages on the terrestrial, aquatic, and atmospheric environments generated by sand mining activities. These damages also harm the social and economic sphere of sustainable development. The degree of impact depends, in part, on the type and intensity of sand mining, the fragility of the different elements of the ecosystem and biodiversity, and country-specific issues [98]. While sand mining provides direct socio-economic benefits for the region or countries (e.g., job creation, tax revenues), the direct and indirect negative environmental impacts can negatively impact other sectors of the economy, such as agriculture, tourism, fishing, public health [2,[99][100][101], and society (e.g., flood protection, access to drinking water, erosion prevention).
The current analysis is especially concerning given that sand resources in many locations around the world are needed to help buffer the adverse impacts of climate change. Specifically, the International Panel on Climate Change projects that the sea level will rise nearly one meter by 2100 [102], and sand in coastal areas is one of the only tools that can help curb the direct impact of rising sea levels on land areas [78]. Governments that allow sand removal from coastal areas, inlets, and rivers may be creating a situation that will compound the environmental damage their countries will experience as a result of sea-level rise associated with climate change. Indeed, in the coming years, they may need to invest significant resources to reinforce coastal areas that have been made more vulnerable as a result of sand mining. Figure 4 presents a cluster map of the social, environmental, and economic impacts of sand mining, based on our analysis of the literature [1,4,19,78,83,91]. One assumption is that as the world population increases, the demand for sand is likely to continue to grow, which corresponds to the increasing need for infrastructure, housing, etc. (viz., socio-economic development). The keywords presented in Figure 4 should be interpreted as part of an initial model for assessing the impact of sand mining on socio-economic development. The model identifies the associations between sand demand, sand mining activities, direct and indirect environmental effects, social impacts, and economic impacts.  [1,4,19,79,84,92]. Understanding the connections and correlations between direct and indirect environmental impacts and social and economic impacts is central to developing and promoting policies and programs that will stimulate and guide the sand industry and governments toward sustainable development practices.  [1,4,19,78,83,91]. Understanding the connections and correlations between direct and indirect environmental impacts and social and economic impacts is central to developing and promoting policies and programs that will stimulate and guide the sand industry and governments toward sustainable development practices.

Conclusions and Future Prospects
Despite the increasing worldwide dependence on sand, the large quantity of sand and gravel excavated, the significant environmental impacts, and the socio-economic issues associated with sand mining and use, policymakers have largely ignored these pressing issues, and the public often has little knowledge of them. Importantly, as the COVID-19 pandemic and other issues take the attention of government officials and the public, this pressing problem may become even less visible.
With the expectation that coastal areas are at increased risk due to rising sea levels associated with climate change, there is little question that sand in coastal areas will play an increasingly greater role in determining the amount of damage from floods and erosion. The findings point to the need for swift action by governments and agencies around the world to create global regulations that prevent the sourcing of more sand than the Earth can naturally create. These actions should consider how regulating sand use could promote economic and environmental stability regionally and within countries and reduce the detrimental effects of sand production and export [4].
The current analysis highlights the need for a global mechanism to monitor sand extraction and its impacts. Scientific and environmental impact assessments should be systematically implemented prior to any authorization for sand extraction. Further, increased efforts are needed to encourage countries to strengthen the enforcement of existing laws and to develop new regulations as needed. These measures should consider ways to resist promoting short-term over long-term benefits and to incorporate environmental consequences in decision-making [78].
The current analysis suggests that governments and the private sector should increase investment in research and development and identify sustainable alternatives for common sand as a building material (such as alternatives to conventional concrete). Finding a suitable alternative may have the potential to reduce carbon dioxide emissions from concrete production, which accounts for nearly 4% of global carbon dioxide emissions [103]. Potential substitutes that are currently available include quarry stone dust, industrial waste [104], plastic waste [105], and wood production residuals [4]. Careful analysis of the environmental and social-economic consequences of alternative materials is needed to determine the pros and cons compared to sand.
The current analysis also gives direction towards promptly developing an international framework for sustainable sand mining. A global framework could include international laws and enforcement mechanisms, such as a licensing system designed to reduce sand use, monitoring systems, and clean technologies that reduce environmental damage. It is likely that such an approach would need considerable support from those countries and businesses most engaged in sand development in order to realize the expected benefits.
Finally, to reduce the negative environmental impacts of sand mining activities, active measures should focus on four areas: a.
informing the general public about the negative effects of sand mining in order to raise awareness of associated environmental issues, b.
engaging governments, agencies, and community members in monitoring and surveillance actions in order to identify potential threats to the environment due to sand mining activities, c.
providing an efficient legal framework for regulating sand mining activities and reducing or preventing illicit mining activities, d.
reducing sand usage by replacing natural sand with substitution material in different industries, As the COVID-19 pandemic creates economic hardship worldwide, there may be new pressures to source sand illegally. In fact, there is evidence that monitoring activities of industries around the world have reduced as a result of COVID-19, as governments take measures to minimize citizen exposure to the virus [106]. Indeed, less developed countries, where the majority of illicit sand sourcing is taking place, have the highest unemployment and poverty rates. Immediate local, national, and international action is needed to address the serious issue of sand exploitation.
Author Contributions: All authors have contributed significantly for this research in all phases and sections. All authors have read and agreed to the published version of the manuscript.