Luossajärvi is a small 260 acres (1.1 km²) lake in Kiruna

Kiruna

Kiruna is the northernmost city in Sweden, situated in Lapland province, with 18,154 inhabitants in 2005. It is the seat of Kiruna Municipality Kiruna (Northern Sami: Giron, Finnish: Kiiruna) is the northernmost city in Sweden, situated in Lapland province, with 18,154 inhabitants in 2005. It is...

 in northern Sweden beside Luossavaara

Luossavaara

Luossavaara is a mountain in Kiruna, Sweden. It is the site of a now-inactive iron ore mine formerly operated by the Swedish mining company LKAB. Today it has a ski lift and slope, as well as a hiking path called Midnattsolstigan ....

. The mining company LKAB

LKAB

LKAB is a Swedish mining company. The company mines iron ore at Kiruna and at Malmberget in northern Sweden. The company was established in 1890, and has been 100% state-owned since the 1950s...

 has gradually emptied the southern part of the lake in 2007-8 to allow mining of iron ore in the peat bog. These drained areas today consist of mostly marshes.

Environmental problems

The remaining portion of the lake has a chemical composition which shows the influence of mining activities. The lake has high concentrations of sulphate and nitrite

Nitrite

The nitrite ion has the chemical formula NO2−. The anion is symmetric with equal N-O bond lengths and a O-N-O bond angle of ca. 120°. On protonation the unstable weak acid nitrous acid is produced. Nitrite can be oxidised or reduced, with product somewhat dependent on the oxidizing/reducing agent...

. The high sulfate concentrations indicate extensive weathering processes of mainly carbonate and sulphorous materials.

Fishing

Fishing is practised on, and every winter ice fishing contests are held out on the ice. The name Luossajärvi derives from the rich number of trout

Trout

Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

 that were in the lake. The original stocks consisted of perch

Perch

Perch is a common name for fish of the genus Perca, freshwater gamefish belonging to the family Percidae. The perch, of which there are three species in different geographical areas, lend their name to a large order of vertebrates: the Perciformes, from the Greek perke meaning spotted, and the...

, trout and pike, but these are now depleted to the point that now only perch naturally remain. The playground for the natural brown trout populations has disappeared due to the mining. However, other fish species have now been planted into the lake, including whitefish

Whitefish

Whitefish or white fish may refer to:In fishing terminology:* Whitefish , a fisheries term referring to the flesh of many types of fishIn fish species:...

, grayling

Grayling (genus)

Thymallus is a genus of freshwater fish in the salmon family of order Salmoniformes; it is the only genus of subfamily Thymallinae. The type species is T. thymallus, the grayling. The genus's five distinct species are generically called graylings, but without qualification this also refers...

, char

Salvelinus

Salvelinus is a genus of salmonid fish often called char or charr; some species are called "trout". Salvelinus is a member of the Salmoninae subfamily of the Salmonidae family. Charr may be identified by light cream pink or red spots over a darker body. Scales tend to be small, with 115-200 along...

, rainbow trout

Rainbow trout

The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....

 and splake

Splake

The splake is a hybrid of two fish species resulting from the crossing of a male brook trout and a female lake trout...

.