The environmental impacts of river sand mining.

The demand for construction-grade sand is growing at a tremendous rate and the world is expected to run out of this resource by 2050. Construction-grade sand, hereafter referred to as 'sand', can be found in (former) aquatic environments, such as rivers and is a provisioning ecosystem service. Even under controlled circumstances, the practice of extracting the sand from the riverbed and -banks impacts the environment. Unfortunately, many countries lack sand mining regulation policies and in combination with a high demand, this results in indiscriminate and illegal mining. To create effective policies for sustainable extraction of river sand, there is a need for both qualitative and quantitative data on the effects of river sand mining. This paper brings together the effects of river sand mining on the physical, biological, chemical, and anthropogenic environment through a systematic literature review. The effects found are widespread and often cumulative. In the physical environment, the primary effects are riverbed widening and lowering. In the biological environment, the overarching effect is a reduced biodiversity and stretches from the aquatic and shoreline flora and fauna to the whole floodplain area. The effects on the chemical environment are a reduced water, air and soil quality through pollution. The effects on the anthropogenic environment comprise of damaged infrastructure, bad working circumstances for workers, limited access to water and agricultural losses. The findings of this research emphasize the complexity and cascading nature of the effects of river sand mining, as well as the severity and urgency of the problem. Based on the effects found and the four environments, a set of guidelines are proposed at the end of this paper to be used for global agenda making regarding sustainable sand extraction. Future research should prioritise quantifying the observed effects and developing science-based policies for sustainable mining.