Lake lowering in sulphide-rich areas is currently a major environmental impact for surface water. This study focuses on whether there is a relationship between a gradient of lake lowering and surface water impacts in areas of sulphide-rich sediments, in order to better understand their contribution of heavy metals and sulfuric acid. Also, is it a reasonable method to use the reduced lake area in order to quantify the gradient? The survey was conducted by collecting water samples from reference lakes and lowered lakes from south to north in coastal areas within the county of Västerbotten. Water samples were then analyzed for TOC, pH, conductivity, anions, base cations, alkalinity, acidity, sulfate, Al, Cd, Fe, Mn, Cu, Zn and Pb.

Ensåsengruvan is a mine situated within Ljusdals municipality in central Sweden. Themine was in use from 1984 to 1991 and has since been undergoing a remediation program. Mine tailings from sulfide rich ore is a potential environmental hazard due to its tendency to cause acid waters and heavy metal leakage. Lake Ensjön is situated one kilometer from the mine area. Due to the hydrological conditions it was not expected to receive inflowing water from the mining area.

The aim of this study was to examine the current and historic mercury(Hg) load of the lake Storjuktan due to its recent exposure to a local potential source of Hg in form of the Sulphide mine Blaikengruvan(2006) and an earlier potential sources of Hg-load, the damming of the lake(1960s). Sediments were extracted using a HTH-sampler, freeze-dried, and analyzed for tot-Hg, LOI and activity of 210Pb and compared to samples extracted prior to the opening of the mine(2006). Constant initial concentration (CIC)-dating model was used for dating the samples. Low levels of Hg (100ng/g) were found throughout the lakes sediment. The highest levels of Hg(220ng/g) was detected at a depth of 4-5cm dating back to the mid 1970:s, suggesting that increased levels of atmospheric Hg rather than damming of the lake has caused the increase of Hg.

The limit for mercury in fish, set by health authorities, is exceeded in about half of the lakes in Sweden. Methyl mercury (MeHg) is the most toxic form of mercury and accumulates in fish. Therefore transformation of inorganic mercury (Hg) to methylmercury (MeHg) is an important process that we need to understand in order to possibly counteract the negative effects of mercury in the environment. The seasonal dynamics of mercury biogeochemistry is likely of great importance for the accumulation of MeHg in the aquatic food web. In thesis the chemical speciation and transformations of Hg and MeHg in bottom waters and sediments is followed in Ängessjön, a small lake located on the east coast in the middle of Sweden. The lake is not directly affected by any industrial pollution and concentrations of Hg in the sediment reflect the atmospheric deposition in this area, as well as processes taking place along the hydrological pathways from soil to lake. Samples from sediment, bottom- and streamwater were collected in average every second month during the period Feb.

In Sweden you will find the coot chiefly in the southern parts. The species winters in the southern part of the Baltic Sea and along the coasts of northern Europe. The number of coots is heavily decreased by harsh winters. The population of the coots in Sweden is estimated to 20 000 to 30 000 pairs. The region of Dalarna is the random zone for the breeding of coots in Sweden .

LKAB is an international high tech mineral corporation and a world leading manufacturer of refined ironore products for steal manufacturing and other mineral products destined other industries. LKAB is an international corporation with companies world wide, with it?s main location in the north of Sweden, which is where the iron ore mines and the refining works are located. LKAB?s iron refining process in Vitåfors, Malmberget, is a source of great amounts of waste-rock.

Eutrophication has been a problem in aquatic systems for a long time. It is well known that the key nutrient to control the eutrophication process is phosphorus. Lately, it has been possible to reverse the process and recover lakes from eutrophication.During a long time Lake Näsnaren in Katrineholms kommun, Södermanland, has been exposed of a large amount of phosphorus from the city's wastewater. The lake has a great value as a habitat of rare species but also a high recreation value for people living in Katrineholm and Södermanland. Lake Näsnaren is situated in a Natura 2000 area.

The discharge from Lake Mälaren is regulated to keep the lake water level within limits set by a water decree. Despite this, in the year 2000 the lake water level rose above the upper limit. Studies conducted at the climate modeling unit Rossby Centre at the Swedish Meteorological and Hydrological Institute (SMHI) indicate that the inflow to the lake may increase in the future. A flood in the area will, among other things, strike infrastructure and residential districts.The aim of this study was to investigate the water levels of Lake Mälaren in future climates. In addition to this possible future expansion of the lake discharge though the sluice gates in order to keep water levels below limits set by the water decree and to prevent flooding of the shoreline were discussed.

The mining industry, in terms of ore excavation and metal production, is and has been important to the Swedish economy. In connection with the ore excavation process, large amounts of partly sulphidic waste are produced. When the metal sulphides are exposed to air and water they are eventually oxidised, which leads to the formation of acidic water with high concentrations of metal cations and sulphate ions, so called Acid Mine Drainage (AMD). This water may reach the nearest surroundings and cause negative environmental effects. By covering the waste with soil or water, the oxidation process can be minimised. At the Rävlidmyran mine in the county of Västerbotten open pit mining took place between 1951 and 1991.

The aim of this study was to examine the amounts of heavy metals in the sediment of a wetland constructed for stormwater treatment. The wetland is called Vattenparken and is located in the city of Enköping. The heavy metals which were analysed were Pb, Cd, Ni, Zn, Cu, Cr and Hg. The total metal concentrations were determined using HNO3 chemical extraction. From 8 sampling sites 5 sediment cores were taken.

The focus of this study was to examine the nutrients and benthic organisms of the bay ?Mönsteråsviken?, which is influenced by eutrophication. The purpose was also to look at an interesting gradient forming in the bay, namely the distance from the river outflow of Lillån. At 18 sampling sites in the bay samples of water, sediments and benthic organisms were collected in late April of 2011. The water was analyzed for nitrate, phosphate and chlorophyll.

The focus of this study was to examine the nutrients and benthic organisms of the bay ?Mönsteråsviken?, which is influenced by eutrophication. The purpose was also to look at an interesting gradient forming in the bay, namely the distance from the river outflow of Lillån. At 18 sampling sites in the bay samples of water, sediments and benthic organisms were collected in late April of 2011. The water was analyzed for nitrate, phosphate and chlorophyll.

The Earths climate is changing at a higher rate, i.e between 1861 and 1994 the annual mean temperature in Scandinavia increased with 0,68º C and according to recent climate models the annual mean temperature is likely to rise with another 3º C during this century.A warmer climate in many ways is associated with changing conditions for lake ecosystems. An expected higher water temperature and a stronger summer stratification of the water column increases the risk of anoxic conditions at the lake bottom. Thus anoxic conditions are likely to cause a phosphate leakage from the sediment, i.e. a higher internal loading of phosphate.In this project, the extremely warm summer of 2002 has been used as an example for a possible scenario for a future climate. By comparing levels of phosphorus in the summer of 2002 with a ten-year median value, a phosphorus related sensitivity to climate change has been analyzed for 55 Swedish lakes.

Österbyverken is an industrial estate in Östhammars municipality in Uppland, Sweden. Many different activities have taken place on the estate the last 600 years. During the last 15 years both health and environmental studies have been made by different companies. At the most recent study a great increase of metals in Nerån, a river that runs partly through and partly next to the estate, was identified with mass balances. The purpose of this thesis is to accomplish a deepened study about the reasons for the increase of metals in Nerån.

There are today large amounts of contaminated sediments in the Baltic Sea. These contaminants are the result of many years industrial activity where the contaminants have not been taken care of and just released out in the water. When ports want to dredge in their fairways and harbor areas the contaminated sediments need to be considered since they are a environmental risk. The development in this area has been slow and new techniques have just recently made its way into dredging operations in the Baltic Sea region. As a result of this there are no clear methods for implementing new techniques today.