Of all fossil fuels lignite has the biggest impact on water resources. It includes wasting water and serious contamination.
Dehydration
Lignite extraction is inevitably connected to large scale dehydration of its deposits, which causes a so-called cone of depression to form around a lignite open-pit. Within its range the groundwaters disappear.
Effects of the creation of cone of depression:
- Decrease of accessible underground water resources, wells and groundwater intake points dry out
- Decrease of underground water pressure causes the water from deeper aquifers to rise - and this water is often salty - and to contaminate the drinking water reservoirs
- Decrease of water level in rivers, lakes, ponds, until they go dry
- Wetlands (often very valuable, like peat bogs) are dessicated and degraded
- Increase of fire threat in forests and on peat bogs
- Desiccation of soil, degradation of farming land
- After the mining is over, flooding the pit takes decades, and it drains the water resources in the surroundings of the mine, while the losses on the surface are not compensated by discharges of clean underground water.
Since the beginning of mining until 2014 Turów mine has pumped out 950 mln m3 of water. Until the end of 2017 it was 1069,1 mln m3.
Turów mine until now has caused a complete loss of water in the historical spa Opolno Zdrój. On the Czech side of the border the residents were forced to deepen the wells at their own expense.
In Summer 2019, drought, heat and increased water intake by the inhabitants, the mine and Turów power plant, caused two drinking water intakes in Bogatynia to dry out. There were interruptions in water supply and a radical deterioration of water quality.
If the mine is expanded and the mining prolonged until 2044, the regional cone of depression will impact water resources in Lower Silesia in Poland as well as in the neighbouring countries. There is a threat of drinking water loss for nearly 30 thousands residents of the Czech region Liberec. Negative impact on aquatic and water-dependent ecosystems - rivers, lakes, wetlands and soil - is also predicted. Natura 2000 sites on the German-Polish border will be impacted.
Pollution
Lignite deposits dehydration causes changes to the chemical composition of water. Heavy metals (Pb, Cd, Hg) and radioactive elements (U, Th) levels increase, while pH decreases (sometimes drastically). Mines become the sources of pollution of water. Mining water also carries large quantities of lignite sludge, which is very harmful to water ecosystems.
The process of water pollution from lignite mining:
- Water containing toxic particles flows into the mining pit, and is being pumped out to the surface water (rivers, ditches) together with lignite sludge.
- Discharge of sewage and clean groundwater from the mine’s drainage system may be so intense that it causes erosion of river beds and physical destruction of water ecosystems.
- After the mining is over, the open-pit is being flooded. Water in the resulting reservoir has a changed chemical composition and often an extreme pH, which makes it uninhabitable for most forms of life. The reservoir becomes a permanent source of pollution of underground water resources.
Turów mine discharges multiple toxic substances to water - including mercury (over 330 kg in 2017, out of which 100 kg was emitted to water and ground). Mercury is one of extremely toxic substances that is being bioaccumulated, and its elimination from water is one of the goals of the Water Framework Directive. Coal burning is the major source of water pollution by mercury in Poland. Mercury that is emitted from Turów mine and power plant pollutes and will pollute water and soil mostly in the regions closest to Zgorzelec district.
