Post a comment on the text below

Impacts

Main impacts to aquatic ecosystems are changes in surface and groundwater hydrology, sediment load, water quality, acidification and alteration in stream habitat and morphology (Figure 6).

Figure 6             Impacts of mining activities on water

Notes: Insert notes here

Source: http://ubclfs-wmc.landfood.ubc.ca/webapp/WID/course/land-use-impacts-on-water-3/mining-impacts-16/ .

All types of mining have the potential to directly disrupt groundwater hydrology, which in turn can affect surface waters that are in hydraulic continuity with the affected groundwater systems (ERMITE-Consortium et al., 2004). This is mainly due to dewatering resulting in a depression of the water table around the dewatered zone.

The water quality of mining activities is mainly affected by acidification or salinization. The acid runoff further dissolves heavy metals such as copper, lead, mercury into groundwater or surface water. Problems that can be associated with mine drainage include iron hydroxide precipitation during oxygenation of mining water, contaminated drinking water (e.g. with metals or sulphate), impacts on aquatic plants and animals, or the corroding effects of the acid on parts of infrastructures ([1]). Salinization is caused by the extraction of salts, e.g. potassium. High salt content altered aquatic communities and salt intrusion into the groundwater can endanger the quality of drinking water.

Placer mining or gravel extraction, and lead to increased sediment loading and decrease water clarity. Furthermore, hydromorphology is impacted by replacing coarse substrates such as gravels and boulders resulting in fewer invertebrate species.

Impacts of the removal of peat are increased sedimentation, increasing dissolved organic carbon (DOC) and phosphorus concentration, and decreasing pH values in the receiving waters (Lundin, et al., 2017; Ramchunder, et al., 2012). The leaching of phosphorus and nitrogen causes eutrophication problems into the watercourses or lakes and the load of solid peat particles causes silting of downstream water bodies.

Hydraulic fracturing to extract shale oil or shale gas potentially threatens drinking water resources (mainly groundwater) with the contamination with chemicals used in the hydraulic fracturing process. Surface water contamination can occur if the wastewater, containing the chemical additives as well as saline water and naturally occurring heavy metals and radioactive materials from the shale formations, is not properly managed and treated (Umweltbundesamt, 2012). Based on the shale gas information platform by EC, the UK is the only country in Europe, where companies pursue hydraulic fracturing (which is haltered since 2019)([2]), whereas a ban in France and Bulgaria and tests in Poland occur ([3]). In Estonia, mines cover ca. 1 % of the whole territory and about 16 million tonnes of shale oil were extracted in 2012 with high impacts on waters ([4]).  

Mining accidents can have tremendous impacts to the aquatic environment, for example the spill of cyanide rich waste water in Baia Mare, Romania in 2000. After a dam brake in the retreatment plant of gold mining company, large number of fish were killed in the Somes River, and also Tisza River and Danube. Furthermore, drinking water resources were contaminated (UNEP/OCHA, 2000).