Springs in the Central Parts of Vallentuna Municipality Traditions and Threats

DEGREE PROJECT IN CHEMICAL ENGINEERING AND TECHNOLOGY, FIRST LEVEL STOCKHOLM, SWEDEN 2017

Springs in the central parts of Vallentuna municipality Traditions and threats

Hannan Hadodo

A stream emerging from a spring horizon in Arkels tingstad, Vallentuna

KTH ROYAL INSTITUTE OF TECHNOLOGY KTH CHEMICAL SCIENCE AND ENGINEERING Degree Project Bachelor of Science in Chemical Engineering and Technology

Title: Springs in the central parts of Vallentuna municipality traditions and threats

Swedish title: Källor i centrala Vallentuna traditioner och hot

Keywords: Spring, water quality, restoration

Workplace: KTH and Vallentuna

References in Vallentuna: Anton Mankesjö, Vallentuna kommun Staffan Rosander, Vallentuna Hembygdsförening Anders Eriksson, Källakademin Nicole Sundin, Vallentuna kommun

Supervisor: Olle Wahlberg

Student: Hannan Hadodo

Date: 2017-11-07

Examiner: Lars Kloo

Abstract Twenty springs in the central parts of Vallentuna municipality have been studied to determine their present water qualities and suggest actions that could be taken to improve the water quality and availability of the springs. The measured parameters are the water volume, the water flow, the water temperature, the pH-value, the electrical conductivity, the chloride concentration, the alkalinity and the CODMn. The sensory properties of the springs were also examined, which include odour, colour, clarity and precipitation. Measurements of the water flows, the water temperatures, the pH-values and the electrical conductivities were performed during a field trip in Vallentuna. During this field trip, two water samples were taken from each spring. Thereafter, the alkalinity, the chloride concentration, the CODMn and the sensory properties were determined in the laboratory. Four of the springs, which were wells, have water of high quality and can easily be restored. Some of the twenty springs have not been cared for or have even disappeared. The water from the spring horizon near Arkels tingstad is unfortunately mixed with stormwater, which runs off the nearby roads. This contamination is examined by measuring the chloride flows of the different streams. The roads also contribute with metal pollution, with metals such as cadmium. Therefore, metal speciations of cadmium were examined. A simple solution is suggested to remove the metal pollution. The measured water flows of all of the spring waters in Vallentuna were quite small. The results of the measurements of the spring waters were compared with the values recommended by Livsmedelsverket and Socialstyrelsen. Most of the values were between the recommended limits for drinking water. Suggestions are given to improve the springs concerning water quality and availability.

Sammanfattning (Abstract in Swedish) Tjugo källor i centrala Vallentuna studerades för att bestämma deras vattenkvalitet och för att föreslå åtgärder i avsikt att förbättra vattenkvaliteten och tillgängligheten av källorna. De mätta parametrarna är vattenvolym, flödeshastighet, vattentemperatur, pH-värde, elektrisk konduktivitet, kloridkoncentration, alkalinitet och CODMn. Dessutom undersöktes källvattnens sensoriska egenskaper, vilka innefattar lukt, färg, klarhet och utfällning. Mätningar av flödeshastigheterna, vattentemperaturerna, pH-värdena och elektriska konduktiviteterna gjordes under en exkursion i Vallentuna. Två vattenprover togs från varje källa. Därefter undersöktes kloridkoncentrationen, alkaliniteten, CODMn och de sensoriska egenskaperna på laboratoriet. Fyra av källorna, vilka var brunnar, har vatten av hög kvalitet och kan relativt enkelt restaureras. En del av de tjugo källorna har inte vårdats under lång tid och har till och med försvunnit. Vattnet från källhorisonten vid Arkels tingstad har olyckligtvis blandats med dagvatten, vilket rinner från de närliggande vägarna. Denna förorening analyseras genom att mäta kloridflödet i olika strömmar. Vägarna bidrar också med metallföroreningar, t.ex. kadmium. Därför har också metallförekomstformer för kadmium modellerats. En enkel metod föreslås för att avlägsna metallföroreningarna. Vattenflödena från källorna i centrala Vallentuna är relativt små. Resultatet av mätningarna av källvattnen jämfördes med de rekommenderade värdena för dricksvatten enligt Livsmedelsverket och Socialstyrelsen. De flesta värdena låg inom gränserna för de rekommenderade värdena för dricksvatten. Förslag ges till förbättring av källorna med avseende på vattenkvalitet och tillgänglighet.

Preface During my degree project, I have learnt to appreciate the value that springs have to us humans. Exploring different locations in nature that are not commonly visited and finding clean spring water was a new experience for me. It shows how we tend to forget that clean water can be accessed not only from water taps, but also from other sources such as wells. Maintenance of spring water gives the opportunity for future generations to enjoy clean water from such sources. I would like to express my sincere thanks to my supervisor at KTH Olle Wahlberg, who came up with my degree project about the springs in Vallentuna. Olle Wahlberg guided and helped me during the course of my degree project. I also wish to thank residents in Vallentuna who gave information about some of the springs, and Källakademin that has expressed interest in my work.

Table of Contents Abstract 3 Sammanfattning (Abstract in Swedish) 4 Preface 5 1 Introduction 8 1.1 Problem 8 1.2 Goal 8 1.2.1 Methods 8 1.3 Aim 8 1.4 Limitations 8 2 Background 10 2.1 Traditions and importance of springs in Vallentuna 10 2.2 Threats to springs in Vallentuna 11 2.3 Water properties 11 2.3.1 Electrical conductivity 11 2.3.2 Chloride 12 2.3.3 pH 12 2.3.4 Alkalinity 12 2.3.5 COD 12 2.4 Solutions for problems with the water quality of springs and wells 12 3 A survey of the studied springs 14 3.1 Springs in area A 15 3.1.1 A1 Kyrkans källa 15 3.1.2 A2 Prästgårdens källa 15 3.1.3 A3 Kullens källa 15 3.1.4 A4 Spring in Åby gård 16 3.1.5 A5 Well in Åbyholm 16 3.2 Springs in area B 16 3.2.1 B1 Well close to the spring horizon 16 3.2.2 B2 Stormwater stream from Skadronvägen 17 3.2.3 B3 Stormwater stream 17 3.2.4 B4 Stream in Arkels tingstad 17 3.2.5 B5 Stream in Hasseludden 18 3.2.6 B6 Spring near Uthamravägen 18 3.3 Springs in area C 18 3.3.1 C1 Well near the brewery house/ washhouse 18 3.3.2 C2 Well near a cow stable of Uthamragård 19 3.3.3 C3 Spring near the main building 19 3.3.4 C4 Old basin used for washing clothes 19 3.3.5 C5 A crofter’s well 19 3.4 Springs in area D 19 3.4.1 D1 Well in a forest 20 3.4.2 D2 Well in a garden 20 3.4.3 D3 Old construction for washing clothes 20 3.4.4 D4 Spring found in the SGU database 20 3.4.5 D5 Deeply drilled well 21 4 Laboratory Methods 22 4.1 Determination of the chloride concentration 22 4.2 Determination of the alkalinity 22 4.3 Determination of the CODMn 23

5 Experiments 25 5.1 Field trip 25 5.2 Sensory properties 25 5.3 Laboratory methods 25 5.3.1 Chloride concentration 25 5.3.2 Alkalinity 26 5.3.3 CODMn 26 6 The chloride flow in Arkels tingstad 27 7 Different forms of metal ions 28 8 Results 29 8.1 Physical-chemical properties of the spring waters 29 8.1.1 Volume of the spring water in the wells 29 8.1.2 Water flow of the streams 29 8.1.3 Water temperature 30 8.1.4 pH-value 30 8.1.5 Electrical conductivity 31 8.1.6 Chloride concentration 31 8.1.7 Alkalinity 32 8.1.8 CODMn 32 8.2 Sensory properties 33 8.3 Chloride flow of Arkels tingstad 33 8.4 Speciation of metal ions 33 9 Discussion 34 9.1 Properties of the springs 34 9.2 Water quality of the springs 34 9.3 Human influence 35 9.4 Improvement of the water quality 35 10 Conclusions 36 11 Bibliography 37 Appendix 1: Images of the spring water samples 39 Appendix 2: Co-ordinates of the springs 41 Appendix 3: Calculations of the water volume and water flow 42 Appendix 4: Laboratory results 43 Appendix 5: Calculations for the analysis methods 44 Appendix 6: Calculations for the chloride flow in Arkels tingstad 45 Appendix 7: Physical-chemical properties measured in the field trip 49 Appendix 8: Physical-chemical properties measured with laboratory methods 50 Appendix 9: Sensory properties of the water samples 51

1 Introduction Vallentuna municipality is located 25 km north of Stockholm centre. Today it is a suburb of Stockholm. There are many springs in Vallentuna that were earlier used as water supplies. Most of these springs are now forgotten or have been contaminated. Some of them have even disappeared. Most people in Vallentuna now use tap water from Mälaren. Some springs can still be restored and enjoyed by people who visit. The springs also have a cultural value, and every courtyard in Vallentuna once used to have its own spring or well. Twenty springs in central Vallentuna are studied in this project. A few of the springs are well cared for, but most of them are forgotten and not maintained. However, the springs are an example of local traditions and the threat to this cultural heritage that the expansion of the modern society leads to. In Vallentuna, the spring water mostly comes from small moraine hills, which is the reason why the water flow is usually small. The ground water influences the water quality of the springs and therefore, the springs have been used to survey the ground water quality by SGU (The Swedish Geological survey).

1.1 Problem Many of the springs in the central parts of Vallentuna municipality are no longer in use. These springs have a potential to be used for drinking water if they meet the requirements for drinking water. The springs of interest will first be located to then determine their water quality. Their water quality can be measured with different measuring devices used directly on the springs and also analytical methods executed at the Department of Applied Physical Chemistry in KTH. Their surrounding environment will also be examined in order to propose methods that can increase their water quality.

1.2 Goal The goal with this degree project is to locate and determine the water quality of the studied springs in the central parts of Vallentuna municipality. The local history and threats to these springs will be reviewed. Solutions to increase the water quality of some of the springs will also be suggested.

1.2.1 Methods Most of the springs will be located by interviewing local residents. Physical-chemical methods and sensory methods will be used to examine the water quality of the springs. Measurements of water flows, water temperatures, pH-values and electrical conductivities are to be performed in the field. The parameters that will be analysed in the laboratory are the alkalinity, the chloride concentration, the CODMn, the odour, the colour, the clarity and the precipitation of the studied springs. The surrounding environment of the springs and the history of some of the springs will also be examined.

1.3 Aim The aim of this degree project is to give information about the springs in the central parts of Vallentuna municipality in order to make them available to the public.

1.4 Limitations This degree project is limited to the springs that are located in the central parts of Vallentuna. The measurements and analyses are limited to temperature, pH, electrical conductivity, water flow, chloride concentration, alkalinity, CODMn and sensory properties of the springs.

The chemical analyses will be performed in the laboratories of the Department of Applied Physical Chemistry in KTH. It is advised that the spring waters are analysed by an accredited laboratory before the public are proposed to drink the spring water.

2 Background Groundwater and spring water are parts of the water cycle, which is run by sun energy and gravity. Precipitation in different forms gives the amount of water that is included in the water cycle. A spring is defined as a continuous flow of ground water from a low point in a terrain (see Figure 1). A stream may lead the water from the spring. [1]

Figure 1 The biogeochemical cycle of water (this image is used with permission from The Swedish Academy of springs) 1) evaporation from snow and ice, 2) rainfall, 3) humid airmasses, 4) condensation, 5) infiltration, 6) runoff, 7) percolation, 8) evaporation from vegetation, 9) groundwater surface, 10) evaporation, 11) lake, 12) spring, 13) river, 14) spring, 15) sea, 16) groundwater stream, 17) marginal zone: freshwater and saltwater [1] In 2015, Niina Veuro studied the cold springs in Täby and Vallentuna in her degree project. Fifteen springs were found in the databases SGU (The Swedish Geological Survey), Skogsstyrelsen (the board of the Swedish Forest Survey) and Riksantikvarieämbetet (the board for the preservation of the Swedish cultural heritage). Niina Veuro provided the geological background of the springs in the area and also suggested how to preserve the springs. She described a spring in Säberg and also mentioned a spring horizon located in Arkels tingstad.

2.1 Traditions and importance of springs in Vallentuna Vallentuna was a farmer’s land in the 19th century. The local train was established in 1885, which was very important for the transportation of the farmer’s products to Stockholm city. Two brickyards and a mechanical industry were localised close to the railway station in Åby farmland during the 20th century, but these industries are presently closed. Vallentuna is today a suburb of greater Stockholm and has a population that is growing rapidly, with more than 30 000 inhabitants in 2017. Åby farm was located right in the centre of Vallentuna. A spring is shown in an old map of Åby village from the year 1775. The spring has disappeared and the area is presently used for parking cars close to the commuter train. All of the farms had traditionally at least one spring or well. The water was used for different purposes such as food preparation, washing clothes, brewing of beer and as drinking water for inhabitants or cows and horses at the stables. Nowadays, most people use tap water originating from Mälaren. The countryside spring water is still used, but deep ground water resources via drilled wells are more often used. [2] [3] [4] [5]

2.2 Threats to springs in Vallentuna Many of the old springs have been forgotten. For example, very few people recognize a spring that is close to the church, which is heavily surrounded with overgrown bushes. The spring in Åby farm has been gone for a long time, but a well in Åbyholm (the outland of Åby farm) still remains. However, the well is covered with litter from a nearby construction site. There is a spring horizon in Arkels tingstad, where spring water flows from a moraine hill down to Vallentunasjön (a lake in Vallentuna) in several small streams. Several springs in this area disappeared between 2015 and 2017 because new houses were built in the valley of Arkels tingstad. The spring water in Arkels tingstad is currently mixed with stormwater from the roads. There is a small spring with a stream running down to Vallentunasjön that the Vallentuna municipality has restored recently. There are still several springs in the farm Uthamra gård, which have been developed into convenient wells. One of the wells is still in use for a stable. Cows and horses were formerly kept in the stable, but it is presently empty. The main farmhouse burnt down in 1961. One of the current owners is restoring a traditional well that belongs to the main farmhouse. There is a well nearby that was formerly used for a brewery house and washing clothes. A different well, which was also used for washing clothes, has been filled out by the present owner. Approximately 500 m north of the stable, there is a typical spring belonging to a crofter’s house, which contained water in June 2015 but was dry September 2017. The outlaying land of Uthamra gård on the eastern side of Vallentunasjön, with the name Nyborg also belongs to Uthamra farm. The hydrology of Nyborg is interesting. There is artesian water in Nyborg, which means that the pressure of the ground water is very high, thus the water casually runs over the borders. It is a problem because the area is planned for new settlements. Nowadays, people usually drill deep holes in the ground for the supply of safe water. [2] [3] [4] [5]

2.3 Water properties The water properties studied in this degree project are the electrical conductivity, the chloride concentration, pH, the alkalinity and CODMn. There are regulations for these parameters so that the water quality is suitable for drinking. There are different regulations depending on the size of the water consumption from the source. Livsmedelsverket (National Futures Association) and Socialstyrelsen (National Board of Health) both have regulations for drinking water (see Table 1). The regulations of Livsmedelsverket apply to water consumption for more than 50 people or for water consumption over 10 m3 per day. [6] The regulations of Socialstyrelsen apply to drinking water from small waterworks and individual wells. [7]

Parameter Livsmedelsverket Socialstyrelsen

Electrical conductivity [mS/m] <250

Chloride concentration [mg/l] <100 <100 pH-value 7.5< pH <9.0 >6.5

CODMn [mg O2/l] <4.0 Table 1 Drinking water regulations from Livsmedelsverket and Socialstyrelsen

2.3.1 Electrical conductivity The electrical conductivity is a measure of the water capacity to carry electric current. It is the sum of several conductivities of ions in the water, resulting from the present electrolytes. That is

11 why electrical conductivity is directly proportional to the dissolved mineral matter of water. The electrical conductivity is dependant of the temperature. [8]

2.3.2 Chloride Chloride is a common anion present in water. Chloride appears naturally in groundwater, and can be found in larger amounts when seawater or road salt makes its way into water. It usually forms different salts with cations of various elements such as calcium, magnesium or sodium. High levels of chloride in water can damage plants if it is used for irrigation, and it can give an unpleasant taste of drinking water. [9]

2.3.3 pH A small number of water molecules dissociate, which results in some ions forming hydroxide ions and others forming hydronium ions. Acidic water contains more hydronium ions than hydroxide ions, and basic water contains the opposite. The pH-value is a measure of how acidic or basic an aqueous solution is, ranging from 0 to 14. The pH of water affects the hardness of the water, which is a measure of metals such as calcium ions and magnesium ions. [10] Pure water has a pH-value very close to 7, which is classified as neutral. Ground water usually has a pH-value between 6 and 8.5. Water that has a pH-value less than 6.5 is considered to be acidic. Acidic water is typically corrosive and soft. It can contain metal ions, such as copper, iron, lead, manganese and zinc. The metal ions can be toxic, result in a metallic taste of the water and cause corrosion of metal pipes. Water that has a pH-value greater than 8.5 is considered to be basic. This water is usually hard, has an alkaline taste and can form scale deposits in pipes. [11]

2.3.4 Alkalinity Alkalinity is a measure of the capacity of water to react with hydrogen ions without a significant change in the pH of the water. This means that it gives information about the acidification sensitivity of the water. The pH-value of a solution that has an alkalinity greater than zero does not change proportionally with the addition of hydrogen to the solution until the alkalinity decreases to zero. [12] [13] The alkalinity of water often depends on the content of bicarbonate, carbonate and hydroxide compounds of calcium, magnesium, sodium and potassium in the water. The alkalinity of water can also depend on the content of borates, phosphates and silicates in the water. Most ground water only contains carbonates and bicarbonates in significant amounts. The origin of bicarbonate is mainly the weathering of rocks. [12]

2.3.5 COD The Chemical Oxygen Demand (COD) is a water quality parameter. It is a measure of the amount of oxygen required to oxidize organic matter in water. It is an important measure because it shows the effect that wastewater can have on the surrounding environment. A high level of COD indicates that the water contains a high level of organic material. The organic material in natural waters oxidizes by dissolved oxygen, which is then consumed. [14] [15] Tap water in Stockholm County contains approximately 2.6 mg O2/l. [16] The oxidation of organic compounds in natural water is a microbiological process.

2.4 Solutions for problems with the water quality of springs and wells The construction and the surrounding area of a spring or a well should be inspected if the water has poor quality. Water quality problems are often due to surface water that leaks into the well or surface activity that affects groundwater. Field operations in the area near the spring or the well can pollute the water system. Relatively common sources of pollution are for example sewers, manure, oil tanks and road water. In some instances, spring water and well water can be contaminated even if there is no new source of

12 pollution near them. Various kinds of field works, such as excavation and drilling, can cause pollutants that were previously stable in soil layers to come into contact with groundwater. Therefore, it is essential that the area near the spring and the well is protected against different sorts of land degradation. It is important to identify the pollution source in order to restore the water quality of the spring water. The source may have to be repaired or removed. It can take a long time to see improvements of the water quality because of the long-term processes of groundwater. Impact of surface activity on the spring water or the well water indicates that other contaminants from the surface can come in contact with the water. It is important to check the places that have a high risk for leakage in wells. In many cases, it is possible to get rid of the problem through different types of sealing techniques. These techniques include replacing the well lid, sealing the joints in buried wells or mounting an extra plastic liner or a sealing cuff in mountain wells. The only solution left if the waterbed is contaminated, and if the source of pollution has not been removed or sealing of the well has not helped, is to construct a new water supply upstream of the source. It is important that the previous spring or well is refilled with sealing material or secured so that the contamination pathway through the well to the groundwater waterbed is eliminated. The new water supply that is built will often have to be located outside of the affected area. Springs or wells that have been contaminated with temporary pollutants of surface water or organic matter that have flowed directly into the well and lead to microbiological growth will often have to be sanitized. A common method is to disinfect these wells with chlorination. It is also advisable to rinse the well to remove any material that could cause bacterial infections in the future. [17]

3 A survey of the studied springs Twenty springs in the central parts of Vallentuna municipality were studied. These springs were located in the parish, which belongs to the old church in Vallentuna. The examined springs were located in four different areas (see Figure 2). These areas were named A, B, C and D. The springs from each area were numbered. All of the samples are shown in Figure 3, larger images of the samples are available in Appendix 1. The co-ordinates for most of the springs are included in Appendix 2.

Figure 2 Map showing the location of the springs that were studied

Figure 3 Image of the water samples taken from the springs

3.1 Springs in area A Springs near the church and in the centre of Vallentuna.

3.1.1 A1 Kyrkans källa

Kyrkans källa is a spring near the old church in Vallentuna. It is located in a small grove at the edge of a ridge not far from the church. It is overgrown by bushes and plants, there are also some scattered stones and mud around it. The well is currently in poor condition. The water level inside the well is 3 cm higher than the water level outside of the well. The spring water of this well slowly flows south towards a paddock nearby.

3.1.2 A2 Prästgårdens källa

Prästgårdens källa is a spring situated at the edge of a ridge behind a cow house in Prästgården. The well is filled with rocks, supposedly for safety reasons. There is currently no water present inside the well because it has been drained by a ditch, which was built to drain the cemetery nearby. This spring was used as a source of water supply for the cows in the house nearby in the twentieth century.

3.1.3 A3 Kullens källa Kullens källa in Väsby gård is between an immense field and the bottom of an inclined forest behind a house. The depth of the water is 0.5 m. The forest ground and the muddy field can possibly affect the water inside the well. The water contained humus from the ground and clay from the field nearby.

3.1.4 A4 Spring in Åby gård The spring is only found on an old map of Åby gård from the year 1775. The spring is no longer visible because it has since disappeared. In the 20th century, two brickyards and a mechanical industry were built in this location. The land is presently used as a parking place for cars near the commuter train.

3.1.5 A5 Well in Åbyholm

The well in Åbyholm and was recently reported in a report by WSP, which is an analysis and technology consulting company. The well is now covered by leftover material from a nearby construction site, as seen in the upper image.

3.2 Springs in area B Springs along the eastern shore of Vallentunasjön, near a spring horizon in Arkels tingstad.

3.2.1 B1 Well close to the spring horizon

The well obtains its water directly from the spring horizon in Arkels tingstad and is located in a garden near a road. There are many new houses being constructed near the well and part of the spring horizon has already disappeared. The diameter of the well is 1.0 m and the depth of the water in the well is 1.1 m. The well has a cover that protects the water from surface contamination.

3.2.2 B2 Stormwater stream from Skadronvägen

The image shows a stormwater stream from a road surface, close to Arkels tingstad. The water flows slowly from a pipe with metal bars. The stormwater pipe is located 50 m away from a pond. Spring water also runs down to the pond.

3.2.3 B3 Stormwater stream

A stormwater ditch that is located close to B2. The water from B2 flows to B3 and then flows to the pond.

3.2.4 B4 Stream in Arkels tingstad

The stream in Arkels tingstad leads the water from the pond, containing both stormwater and spring water down to the lake Vallentunasjön.

3.2.5 B5 Stream in Hasseludden

The water of this stream flows down to the lake in Hasseludden, which is about 200 m from Arkels tingstad. The stream starts approximately 800 m south of Hasseludden near the road Uthamravägen and runs along the spring horizon. Several small streams from the spring horizon flow to this stream. It contains spring water and stormwater from roads.

3.2.6 B6 Spring near Uthamravägen

The image shows a small stream of spring water near Uthamravägen continues to Vallentunasjön. Vallentuna municipality cares for the place where it is located and the stream has been nicely restored.

3.3 Springs in area C Springs located in the old farm village Uthamra gård.

3.3.1 C1 Well near the brewery house/ washhouse

The well near the brewery house/ washhouse is located not far from a moraine hill full of old graves, i.e. ancient relics. The well becomes dry by the end of summer.

3.3.2 C2 Well near a cow stable of Uthamragård

The well is located close to a stable in a field of growing wheat. The diameter of the well is 1.0 m and the well is sealed with a lock. The depth of the water inside the well is 3.6 m. The water has been used for the cows and horses in the nearby stable, which is presently empty.

3.3.3 C3 Spring near the main building

The main well has been filled with sand and bricks to protect children from accidents. It has now been restored by one of the present owners, Peter Kristiansson. The well is constructed with big natural stones. It was formerly covered with a millstone from a nearby windmill.

3.3.4 C4 Old basin used for washing clothes A very old constructed basin used for washing clothes in the 20th century and earlier. No picture could be taken of the basin because the present owner Bernt Bodin has filled it with soil.

3.3.5 C5 A crofter’s well

The well is very close to the remnants of a small house, which disappeared about 80 years ago. The spring was full of water in the beginning of the spring, but it became dry during the summer. There is a stone construction at the end of the pit where water was formerly collected.

3.4 Springs in area D Springs located in Nyborg, the outland of Uthamra gård.

3.4.1 D1 Well in a forest

This well is located in a forest. The diameter of the well is 0,7 m, and the depth of the water in the well is 1,9 m.

3.4.2 D2 Well in a garden The well is located in a garden belonging to a house in Nyborg. The depth of the water in the well is 1,4 m.

3.4.3 D3 Old construction for washing clothes

A basin, which probably has been used for washing clothes, was found in Nyborg. It was filled with water in the beginning of the spring, but was dry during the summer. The water emerged from a small spring located 10 m away. The water was not suitable for drinking, but well enough for washing clothes. There is a two-story concrete house nearby.

3.4.4 D4 Spring found in the SGU database No picture could be taken of this spring because it was located inside a locked house. The water was furnished from a nearby well 50 m away, which was also not accessible.

3.4.5 D5 Deeply drilled well The most common water supply to the population of Vallentuna is currently tap water from the lake Mälaren. The second option most people use is water from a deeply drilled hole in a rock that is typically 100 m deep. The picture shows a deeply drilled well in Nyborg. Though most drilled wells are hidden, this one can easily be seen. The pump is drained at the bottom of the well.

4 Laboratory Methods

The determination of the chloride concentration, alkalinity and CODMn can be done with analytical chemistry methods.

4.1 Determination of the chloride concentration The chloride concentration of the water can be measured with a titration using silver nitrate (��0!). The silver nitrate is used as the titrant in this method because silver ions form insoluble salts with halide elements such as chloride. The salt that is formed from silver and chloride ions is silver chloride (��).

An indicator that can be used for titrations with silver nitrate is potassium chromate (�!��!). The solution containing chloride ions appears yellow once drops of potassium chromate are added to the liquid. Thereafter drops of the titrant are carefully added to the mixture, which results to the following reaction: ��! + ��! ⟶ �� (�) A white precipitate of silver chloride forms in the solution as long as the colour indication of the solution is yellow. The titrant is to be added to the mixture until there are no free chloride ions in the solution. A reddish colour change is visible once all of the chloride ions are consumed. That is when the following reaction occurs: ! !! 2�� + ��! ⟶ ��!��! (�) A red precipitate of silver chromate forms in the solution. Silver chromate only appears after all of the chloride ions are consumed because the momentum for silver and chloride ions to react is higher than that for silver and chromate ions. The titration is complete once there is a sign of red precipitation in the solution. [18] The results from the titration can be calculated to determine the chloride concentration of the solution containing the sample. The formula that can be used to calculate the chloride concentration is determined with the reaction formula for silver and chloride ions. The molar ratio of the reaction of silver and chloride ions is 1:1, which results to the following formula:

�!"!#$%!×�!"! = �!"!#$%&×�!"! The definition for each parameter:

�!"!#$%! The titrant volume

�!"!#$%& The titrand volume

�!"! The concentration of silver ions in the titrant

�!"! The concentration of chloride in the titrand

4.2 Determination of the alkalinity The alkalinity of water is due to the presence of hydroxide ions (��!), bicarbonate ions ! !! (��! ) and carbonate ions (��! ). However, bicarbonate ions and hydroxide ions are in equilibrium state according to the reaction: ! ! !! �� + ��! ⟶ ��! + �!� The alkalinity of water can be determined by titrating the water with a standard acid solution, for example hydrochloric acid. An indicator that is suitable for this titration is a mixed indicator containing methyl red and bromcresol green. A sample that has an alkalinity value greater than zero will appear pink once drops of mixed indicator are added to it. The following reactions occur during the titration with the standard acid solution:

! ! �� + � ⟶ �!� !! ! ! ��! + � ⟶ ��! The alkalinity of the solution is zero once all of the hydroxide ions and carbonate ions are consumed. The solution has a faint greyish colour at this stage of the titration. The presence of the indicator results to a greyish appearance of the solution. It is pink in alkaline solutions. Two drops of the indicator are enough to distinguish the colour of the solution. [19] The titration is complete once the pink colour in the titrand has disappeared. The alkalinity of the titrand can be calculated once the required amount of titrant to decrease the alkalinity to zero is known. The formula that can be used to calculate the alkalinity is determined with the reaction formulas for the titration. The molar ratio between the reactants in both of the reaction formulas is 1:1, which results to the following formula:

�!"!#$%!×�!"# = �!"#$%&×�!"# Where each parameter has the definition:

�!"!#$%! Consumed titrant volume

�!"#$%& Sample water volume

�!"# Hydrochloric acid concentration in the titrant

�!"# Alkalinity of the water sample

4.3 Determination of the CODMn The COD of a solution can be determined with a titration of an oxidant to the solution. A suitable oxidant for this method is potassium permanganate (��!). Manganese has the oxidation state +7, and has a high redox value in low pH-values. The redox potential of potassium permanganate is strongly affected by the pH of the solution, where the oxidation state of manganese varies from +2 to +6 depending on the pH and reactant of the system. The reaction formula for the titration differs depending on the pH condition of the titrand. [20] Strongly acidic solution: ! ! ! !! ��! + 8� + 5� ⟶ �� + 4�!0 Alkaline solution: ! ! ! ��! + 2�!� + 3� ⟶ ��! (!) + 4�� Neutral solution: ! ! ! ��! + 4� + 3� ⟶ ��! (!) + 2�!0

The solution can be acidified with sulphuric acid (�!��!) in order to achieve the first reaction for the titration with potassium permanganate. The solution becomes pink when potassium permanganate is added to it because potassium permanganate has a pink/ purple colour. The solution should be heated in boiling water after a small amount of the titrant is added to it in order for the reaction to occur. The solution will turn clear once all of the permanganate is consumed in the reaction. If the solution stays pink after heating, then the permanganate will no longer react because all of the organic compounds in the solution have been oxidized.

A standard reference is needed in order to determine the CODMn of the solution in interest. A solution with a known amount of CODMn can be used as the standard reference, where the process for the titration with potassium permanganate is executed on the solution. If the CODMn of tap water is known then tap water can be used as a reference.

The number of drops used for the titration of tap water can be compared to the amount consumed by the solution with the unknown amount of organic material to calculate the CODMn of the solution. The following formula can be used to calculate the CODMn:

!!"#$%&×!!"# �!"# = !" !!"# Where each parameter has the definition:

�!"#!! CODMn of the sample

�!"#$%& Number of potassium permanganate drops consumed by the sample

�!"# CODMn of the tap water (standard reference)

�!"# Number of potassium permanganate drops consumed by the tap water

5 Experiments The measurements made to determine the quality of the spring waters were executed during a field trip in Vallentuna and in the Department of Applied Physical Chemistry in KTH.

5.1 Field trip The water samples were taken from the springs during a field trip in Vallentuna in June 2017. However, the sample D3 was taken on a different occasion in February 2017 (D3 was dry in June). The springs were located with maps and the assistance of Olle Wahlberg. Two water samples were taken from each spring once the spring was found. The water samples were stored in plastic water bottles. Some springs were dry and therefore no water samples could be collected from these springs. Different measurements were made of the water to collect useful data from the springs. The diameter, depth from the top of the well to the surface of the water and the depth to the bottom of the well were measured for each well to determine the water volume inside of them. The water flow was determined by the spot-log method. Data such as depth, length and width of a specific volume in the spring waters that had a flow were collected to prepare measurements for the spot-log method. Then the time it took for a stick to flow through the specific volume was measured several times. The calculations made for the water volume in the wells and the water flows of the streams are illustrated in Appendix 3. The GPS co-ordinates for each spring were taken with a smartphone, which gave our location. The temperature of each spring was measured with a thermometer. The pH value was measured with a pH-meter. Lastly, the electrical conductivity was measured with an electrical conductivity meter.

5.2 Sensory properties The sensory properties of all of the water samples were explored. The sensory properties that were examined were smell, taste, colour, clarity and precipitate. All of the water samples were compared to achieve a realistic conclusion for the sensory properties of the samples. The sensory properties for each water sample were noted.

5.3 Laboratory methods Three laboratory methods were executed to determine the chloride concentration, the alkalinity and CODMn of the water samples. The laboratory work was performed in two occasions. The methods of determining the alkalinity and the chloride concentration of the water samples were executed at the first occasion, and the method for determining the CODMn was executed at the second occasion. Determination of the chloride concentration, the alkalinity and CODMn of the water samples were made with different titration methods. The results from all of the laboratory methods are found in Appendix 4. The calculations made to determine the chloride concentration, the alkalinity and the CODMn of the water samples are illustrated in Appendix 5.

5.3.1 Chloride concentration The titrant used for this method was 100.0 mM silver nitrate. The silver nitrate was poured into a burette. 100.0 ml of the water sample that was going to be analysed was transferred into a suitable flask with a graduated pipette. Thereafter 3 drops of the indicator potassium chromate was added to the flask containing the sample. A magnetic stirrer was used to mix the substances, and the solution inside the flask turned yellow. The titrant was dropped into the flask until a reddish colour was visible in the solution. The volume of the consumed titrant, which was visible on the burette, was noted. This method was repeated for each water sample.

5.3.2 Alkalinity The titrant, which was 10.42 mM hydrochloric acid, was poured into a burette. 10.0 ml of the water sample that was to be analysed was transferred to a suitable flask with a graduated pipette. 3 drops of the indicator were added to the sample inside the flask. A magnetic stirrer was used to mix the components. The titrant was dropped into the solution until it turned grey. The value for the consumed amount of titrant solution was noted. This method was repeated for each water sample.

5.3.3 CODMn

The method for the determination of the CODMn was first executed with tap water and then executed with the water samples to compare the sample results with the result for tap water. A determined amount of tap water was poured into a test tube. The water in the test tube was then acidified with 3 drops of 4.5 M sulphuric acid. A drop of 2,0 mM potassium permanganate was added to the solution in the test tube, which resulted to a pink colour in the solution. The test tube was then placed in a beaker containing boiling water for approximately 1 minute. The test tube was then taken out of the beaker. If the solution inside the test tube was uncoloured an additional drop of permanganate was added to the solution and the test tube would once again be placed on the beaker containing the boiling water. This process was repeated until the solution would retain its pink colour. The total amount of potassium drops that were added to the solution was noted. This method was then repeated for all of the water samples. Some of the water samples had very high levels of CODMn and consumed an immense amount of potassium drops, which was time consuming. These samples were diluted to shorten the time it took to analyse them. The samples that were diluted were A3 and D3. 10.0 ml of theses samples was diluted to 100.0 ml with distilled water. The method for determining CODMn was then executed on the diluted solutions.

6 The chloride flow in Arkels tingstad The chloride flow in Arkels tingstad was studied (see Figure 4). The calculations, shown in Appendix 6, were made to estimate the percentage of spring water and stormwater respectively, in the mixed stream. The transport properties of the water and the chloride were used to calculate the proportions of spring water and stormwater that the mixed flows contained.

Figure 4 Water flows in Arkels tingstad The stormwater running off the roads is mixed with the spring water. The mixed stream B4 contains 64 % spring water (B1) and 36 % stormwater from the roads (B3). The mixed stream B5 contains 72 % spring water (B7) and 28 % stormwater from the roads (B8). The spring water flows from a spring horizon shown in Figure 5.

Figure 5 Image of the spring horizon near Arkels tingstad (the slope to the left)

7 Different forms of metal ions Chemical substances appear in different forms at different pH-values and pe-values. This can be modelled with diagrams created with the computer program Medusa. Cadmium is given as an example here. The negative ions that are commonly present in ground water were also included in the !! !! ! diagrams. These negative ions are carbonate (��! ), sulphate (��! ) and chloride (�� ). The pe-value is a measure of the redox-value of a solution. Two diagrams were made for each studied compound, one with a low redox-value and one with a high redox-value. The diagrams for the oxygen poor environment have the pe-value of -5.00, and the diagrams for the oxygen rich environment have the pe-value of 13.00.

Figure 6 Cadmium speciation in oxygen poor water Figure 7 Cadmium speciation in oxygen rich water

Cadmium ions are precipitated as cadmium sulphide (��) between the pH-values 6.3 and 7.6 in oxygen poor environments as shown in Figure 6. In oxygen rich environments between the pH- values of 6.3 to 7.6, the cadmium ions are present as cadmium ions (��!!), cadmium ! ! monochloride (�� ), cadmium sulphate (��!) and cadmium bicarbonate (��! ) as shown in Figure 7. Cadmium can be removed from the springs if it is precipitated within the pH-values of the studied springs. In streams, a deep well can be built in order to collect the precipitation in the water that flows over it. The precipitation that flows in the water sinks to the bottom of the built in well because it has a higher density than water.

8 Results The results from different measurements and observations made include the physical-chemical and the sensory properties of the spring waters. The mixtures of stormwater and spring water of two streams in Arkels tingstad have been examined. The results from the speciation of cadmium in oxygen rich and oxygen poor water are also included.

8.1 Physical-chemical properties of the spring waters The physical-chemical properties include the water volume, the water flow, the temperature, the pH-value, the electrical conductivity, the chloride concentration, the alkalinity and the CODMn of the springs. The physical-chemical properties measured in the field trip and the properties measured in the laboratory are in Appendices 7 and 8 with their measurement errors.

8.1.1 Volume of the spring water in the wells The volumes of the spring water in the wells that were tested are shown in Table 2. The measurement error of the water volumes is 2 %.

Spring Volume [l]

A1 21.2 ± 0.5

B1 825 ± 20

C1 385± 10

C2 2804 ± 60

D1 796 ± 20

D2 1076 ± 25 Table 2 The volumes of water in the wells

8.1.2 Water flow of the streams The water flows of the streams are shown in Table 3. The measurement error for the water flow is based on the time that was measured for the water flow.

Spring Water flow [l/s]

B3 0.7 ± 0.2

B4 1.1 ± 0.4

B5 34 ± 10

B6 1.3 ± 0.4 Table 3 The water flows of the streams

8.1.3 Water temperature The water temperatures of the springs that were visited in June vary from 8.3 ℃ to 18.3 ℃ (see Figure 8). The spring D3 that was visited in February had the lowest water temperature, which was 6.5 ℃. The measurement error for the temperature is 0.5 ℃.

Water temperature

20 18.3 18

] 16 13.1 13.6 ℃ 14 12.8 11.1 12 10.4 9.4 9.8 10 8.3 8.3 8.5 8.6 8 6.5 6

Temperature [ 4 2 0 A1 A3 B1 B2 B3 B4 B5 B6 C1 C2 D1 D2 D3 Spring

Figure 8 The water temperatures of the springs

8.1.4 pH-value The pH-values of the springs vary from 6.3 to 7.6 (see Figure 9). The measurement error of the pH-value is 0.2. The lower limit of the diagram is the recommended lowest value of the pH for drinking water according to Socialstyrelsen, and the upper limit value is according to Livsmedelsverket. All of the pH-values for the springs are within the upper and lower limit except for D3 that has a pH-value of 6.3, but there is a possibility that its pH-value is within the limits because of the measurement error.

pH-value

10 9 8 7.4 7.6 7.4 7.4 7.0 7.0 7.0 7.0 6.9 6.6 6.7 7 6.5 6.3 6 5 Lower limit 6.5 4 pH-value 3 Upper limit 9.0 2 1 0 A1 A3 B1 B2 B3 B4 B5 B6 C1 C2 D1 D2 D3 Spring

Figure 9 The pH-values of the springs

8.1.5 Electrical conductivity The electrical conductivity varies from 7.0 mS/m to 60.4 mS/m (see Figure 10). The electrical conductivity has a measurement error of 10 % for all of the springs. The limit in the diagram is the highest recommended value for the electrical conductivity of drinking water according to Livsmedelsverket. The electrical conductivities for all of the springs are under the limit.

Electical conductivity

300

250

200

150 Limit 250 mS/m 100 60.4 52.4 52.0 49.5 36.8 44.3 50 33.8 28.2 29.1 16.7 12.5 7.0 10.0 Electrical conductivity [mS/m] 0 A1 A3 B1 B2 B3 B4 B5 B6 C1 C2 D1 D2 D3 Spring

Figure 10 The electrical conductivities of the springs

8.1.6 Chloride concentration The chloride concentrations of the springs vary from 9.2 mg/l to 79.4 mg/l, where the chloride concentration for the stormwater in B2 and B3 is the highest (see Figure 11). The measurement error for the chloride concentration is 10 %. The limit in the diagram is the highest recommended value for the chloride concentration of drinking water according to Livsmedelsverket and Socialstyrelsen. All of the chloride concentrations for the springs have values within the recommended limit for drinking water.

Chloride concentration

120

100 79.4 79.4 80 58.9 60 39.7 40 29.1 Limit 100 mg/l 14.9 18.4 18.1 20 9.2 9.9 10.6 10.6

0 A1 A3 B1 B2 B3 B4 B5 B6 C1 C2 D1 D2 Chloride concentration [mg/l] Spring

Figure 11 The chloride concentrations of the springs

8.1.7 Alkalinity The alkalinities of the spring waters vary from 0.57 mekv/l to 5.63 mekv/l (see Figure 12). The measurement error for the alkalinity of the springs is 7 %.

Alkalinity

6 5.63

4 3.39 3.23 2.98 2.92 2.87 3

1.82 1.72 2 1.56 1.51 1.30 1.00 Alkalinity [mekv/l] 1 0.57

0 A1 A3 B1 B2 B3 B4 B5 B6 C1 C2 D1 D2 D3 Spring

Figure 12 The alkalinities of the springs

8.1.8 CODMn

The CODMn of the spring waters varies from 1.3 mg O2/l to 17.3 mg O2/l (see Figure 13). The measurement error for the CODMn is 5 %. The limit in the diagram is the highest recommended value for the CODMn of drinking water according to Livsmedelsverket. The CODMn of A3 is higher than the CODMn of the rest of the spring waters. Only C2, D1 and D2 are within the recommended limit for CODMn in drinking water. The rest of the spring waters have a CODMn that is higher than the limit.

CODMn 20 17.3 18 16

/l] 14 2 11.3 11.7 12 10 8.7 [mg O 7.8 7.8 7.4 Mn 8 6.5 Limit 4.0 mg/l 6 4.3 3.9 COD 4 3.0 1.3 2 0 A1 A3 B1 B2 B3 B4 B5 B6 C1 C2 D1 D2 Spring

Figure 13 The CODMn of the springs

8.2 Sensory properties The sensory properties examined were odour, taste, colour, clarity and precipitate. There is a detailed description of the sensory properties in Appendix 9. The spring waters B4, D1 and D3 did not smell good. The rest of the spring waters did not have distinct bad smells. The taste of the spring waters D1, D2 and D3 was not examined. The spring waters B2, B3 and B4 did not taste well. The taste of the rest of the spring waters was adequate. The spring waters A1, B1, B2, B6 and C2 were colourless. The rest of the spring waters had a brown colour. Nearly all of the spring waters were clear except for A3, B4 and D3, which contained visible particles. All of the spring waters had a small precipitate, except for D1 and D2.

8.3 Chloride flow of Arkels tingstad Table 4 shows how much water and Table 5 shows how much water and chloride that comes from B1 and B3 to B4. chloride that comes from B7 and B8 to B5. To B4 Source Precent To B5 Source Precent

Water from: B1 36 % Water from: B7 72 % B3 64 % B8 28 % Chloride B1 6 % Chloride B7 23 % from: from: B3 94 % B8 77 % Table 4 Precent of water and chloride that flows to Table 5 Precent of water and chloride that flows to B4 B5

8.4 Speciation of metal ions Different forms of cadmium ions depending of pH- and pe-values are shown in Figures 6 and 7. In oxygen rich spring water, cadmium is dissolved in the water and is transported to Vallentunasjön. In oxygen poor water, cadmium is precipitated. This can be used to remove the metal ion pollutions by introducing at deep constructed well in the stream.

9 Discussion Twenty springs in the centre of Vallentuna have been studied for this degree project. The water quality of some of the springs that were examined can certainly be improved with simple methods. These springs can be opened for the public to enjoy if they are restored. There is an example of a well that Vallentuna municipality has earlier restored, which is now available to the public. It is a small spring with a stream in Uthamravägen 94. The present owner of Uthamra farm is restoring the main well in Uthamra gård, which is a good example of a traditional well. All of the obtained chemical analysis results in this degree project were not performed in an accredited laboratory, but done in the laboratory of the Department of Applied Physical Chemistry in KTH. Therefore, it is recommended that the analyses be executed in an accredited laboratory before the municipality of Vallentuna recommends the sources to the public.

9.1 Properties of the springs The properties that were examined for each spring were the water volume, the water flow, the temperature, the pH, the electrical conductivity, the chloride concentration, the alkalinity and the CODMn. The properties that were measured of the springs are not enough to determine whether the water quality is high enough for drinking water, because there are several other properties that should also be measured. The water volume measured is that of accessible wells, and the water flows estimated are those of visible streams from springs. The water volumes of the examined wells differ from each other. The well C2 contained the highest volume of water out of all of the wells, which is important if it is used as drinking water for many cows. The spring near the church (A1) contained the smallest volume of water from the rest of the wells. The reason why A1 contained such a small water volume is that it is filled with soil. The water flows of all of the streams measured in Vallentuna were quite small except for B5, which had a big flow of water from the spring horizon near Arkels tingstad. The water temperatures of the springs were different. The expected temperature of a good spring is between 6 ℃ and 8℃, which is close to the ground water temperature. Only one of the springs had a temperature between 6 ℃ and 8℃ and seven springs had water temperatures below 10 ℃, which is acceptable. The pH-values of all of the springs were quite similar, only ranging from 6.3 to 7.6. The electrical conductivity values of the springs differed, which could depend on the properties of the ground. The chloride concentrations of the samples were reasonably low, except for the stormwaters B2 and B3. This was probably because of excess chloride that comes from the roads nearby. The salt from the roads impacts the ground waters. The alkalinity of some of the springs was quite low. The pH-value of water that has a low alkalinity has a high risk of changing. The alkalinity of C1 was especially low, which can depend on the weathering of minerals. The alkalinity of C2 is very high, which can possibly be for the reason that it is located in a wheat field.

9.2 Water quality of the springs The results show that all of the springs tested were within the recommended values of the electrical conductivity and chloride concentration for drinking water. All of the springs had pH- values within the drinking water limits, except for D3 that had a pH-value slightly lower than the limits for drinking water. However, there is a possibility that the pH-value of D3 is within the limits because of the measurement error, which in this case is 0.2. The parameter that most of the spring waters had values over the recommended limit for drinking water was CODMn. Only C2, D1 and D2 were under this limit. The alkalinity of C1 was quite low, which can contribute to the pH-value of C1 to change and end up outside of the recommended limits for drinking water.

Overall, the springs that had the best water qualities were A1, B1, C1 and C2. The sensory properties of these springs were most pleasant out of all of the spring waters that were tested. The water of these springs smelled and tasted good and was quite clear, but they all had a small amount of precipitate. A parameter that made A1, B1 and C1 not suitable as drinking water was the CODMn level. However, the CODMn level of C2 is suitable for drinking water. The spring waters with the worst sensory properties out of all of the examined spring waters were A3, D1 and D3. The spring water of A3 and D3 was quite brown with precipitate. Although D1 looked quite clear, it had a distinct bad smell, and so did D3.

9.3 Human influence The expanding society threats many traditional springs. An example of this is seen on the old spring located in Åby farm village near the railway station in the centre of Vallentuna parish. This spring is found in a map from the year 1775, but has since then disappeared. There is currently a parking place near to the railway station where the old spring was located. On the outland of Åby village, called Åbyholm, there is a spring transformed to a convenient well. However, this well is currently under threat from the expansion of houses being built in the area. There is an interesting spring horizon in Arkels tingstad, which was found by Niina Veuro but not examined by her. She found springs near a newly constructed road in Arkels tingstad. The spring water close to the road flows down streams to Vallentunasjön. The spring water contains stormwater from the roads. For this reason, the stormwater and the water from the spring horizon were examined in this degree project. The results from the chemical analysis were that the stormwater had a higher chloride concentration than the water from the spring horizon, which contributed to higher chloride concentrations in the streams. The stormwater is probably affected by road salt that is placed on the road in the wintertime, which is the reason for the increased chloride concentration in the water. The water containing the chloride from the roads then flows to Vallentunasjön.

9.4 Improvement of the water quality The water quality of many springs and wells that were studied can easily be improved with suitable actions for wells, where different sealing techniques can be applied the wells with contaminated water. These techniques are especially recommended for the wells A1, B1, C1 and C2 because they had the best water quality out of all of the springs, and simple methods such as sealing techniques can work to improve the water quality enough to use them as drinking water. The spring near the old church (A1) can be enhanced by removing the bushes surrounding it and placing a few stones around it to protect it. The water quality of the streams in Arkels tingstad can be improved by creating a barrier between the roads and the stormwater. As a result, the chloride concentration in the stormwater will decrease and the streams will have cleaner water, which then flows to Vallentunasjön. The speciation models for cadmium show that cadmium precipitates in oxygen poor water. If a deep well were constructed in streams to produce an oxygen poor environment, cadmium would precipitate in the bottom, and therefore, be removed from the water. Many other metals like zinc, lead and copper could also be removed in the same way. This would gradually decrease the metal concentration in the water of the streams.

10 Conclusions Thanks to the information collected from local residents material about the springs could be retrieved, for example their localizations, traditions and threats. Twenty springs were examined and most of them had been transformed into more convenient wells. Altogether, they give an interesting view of the history of the local traditions of the springs. In the developing society these traditions are changed or forgotten. Four of the studied wells had good water quality. The rest of the studied springs had poorer water quality. The majority of the spring waters contained a high amount of organic materials, which impairs the water quality of the springs. The four spring waters that had good water quality were from wells. Their water quality can be improved with different sealing techniques so that the water stays clean. If this is done, then the values of the different parameters that were measured can become appropriate for drinking water. Creating a barrier between the roads and the water that flows to streams can decrease the chloride concentration of two streams located in Arkels tingstad in Vallentuna. A way to decrease the concentration of metals in the streams is by building a well that collects precipitation of the metals. If these suggestions to increase the water quality of some of the streams are taken into account by Vallentuna municipality, then they can one day be available to the public to enjoy as drinking water.

11 Bibliography

[1] Källakademin, Källor i Sverige. Sundbyberg, Sweden: Svensk Byggtjänst för författarna, 2006.

[2] Olle Wahlberg, Supervisor. personal communication.

[3] Staffan Rosandel, personal communication.

[4] Lars-Erik Björkhem, personal communication.

[5] Peter Kristiansson, personal communication.

[6] Livsmedelsverket, "Livsmedelsverkets föreskrifter om dricksvatten," 2015.

[7] Socialstyrelsen, "Socialstyrelsens allmänna råd om försiktighetsmått för dricksvatten," 2003.

[8] N Manivasakam, "Electrical Conducticvty," in Industrial Water Analysis Handbook. India: Chemical Publishing Company, Inc., 2011, p. 147.

[9] (2013) Clean Water Store.

[10] Ingegerd Rosborg and Frantisek Kozisek, "Macrominerals at Optimum Concentrations - Protective Against Diseases," in Drinking Water Minerals and Mineral Balance, Ingegerd Rosborg, Ed. Switzerland: Springer International Publishing, 2015, p. 33.

[11] Anne Marie Helmenstine. (2017, August) Learn about the pH of Water.

[12] N. Manivasakam, "Alkalinity," in Industrial Water Analysis Handbook. India: Chemical Publishing Company Inc., 2011, pp. 71-79.

[13] Margareta Eriksson and Olle Wahlberg, "Vattenkemi," Institutionen för kemi, Stockholm, 2016.

[14] Michael H. Gerardi, "COD," in Troubleshooting the Sequencing Batch Reactor. Pennsylvania, USA: John Wiley & Sons, Inc., 2010, p. 41.

[15] Real Tech Inc. Chemical Oxygen Demand.

[16] Christer Berg, "Vattenkvalitet vid Norsborgs vattenverk 1995," Stockholm Vatten,.

[17] Göran Risberg and Lena Ojala, "Dricksvatten från enskilda brunnar och mindre vattenanläggningar," in Handböcker för handläggning. Lindesberg, Sverige: Bergslagens Grafiska, 2006.

[18] Evelyn M. Rattenbury, "Argentometric Titrations," in Introductory Titrimetric and Gravimetric Analysis. Kent, England: Elsevier Ltd., 1966, pp. 65-66.

[19] Ocheme James, "Experiment on Determination of Alkalinity of a Water Sample Test,"

Januari 2017.

[20] Aileen Hendratna, "The Application of MnO2 and KMnO4 for Persistent Organic Compunds and COD Removals in Wastewater Treatment Process," Royal Institute of Technology, Stockholm, Degree Project 2011.

[21] Michael H. Gerardi, "COD," in Troubleshooting the Sequencing Batch Reactor. Pennsylvania, USA: John Wiley & Sons, Inc., 2010, p. 41.

[22] Ocheme James. (2017, Januari) Experiment on Determination of Alkalinity of a Water Sample Test.

[23] Olle Wahlberg, Springs in Vallentuna.

[24] Staffan Rosandel, Springs in Vallentuna.

[25] Lars-Erik Björkhem, Springs in Vallentuna.

[26] "Socialstyrelsens allmänna råd om försiktighetsmått för dricksvatten ," Socialstyrelsen, 2003.

[27] Anne Marie Helmenstine, "Learn about the pH of water," August 2017.

[28] "Livsmedelsverkets föreskrifter om dricksvatten," Livsmedelsverket, 2015.

[29] Real Tech Inc., "Chemical Oxygen Demand,".

[30] Clean Water Store, "Effects of Chloride in Well Water, and How To Remove It," 2013.

Appendix 1: Images of the spring water samples Images of the water samples from the studied springs are found below.

Water samples from area A An image of the water samples A1 and A3. The bottle A2 is empty.

Water samples from area B An image of the water samples B1, B2, B3, B4, B5 and B6.

Water samples from area C An image of the water samples C1 and C2.

Water samples from area D An image of the water samples D1, D2 and D3.

Appendix 2: Co-ordinates of the springs The co-ordinates of all of the studied springs are illustrated in the table below.

Spring RT90

A1 6603186, 673793

A2 6603218, 673590

A3 6603449, 672950

A4 6603414, 674751

B1 6601439, 672908

B2 6601455, 672819

B3 6601455, 672819

B4 6601403, 672759

B5 6601268, 672642

B6 6600511, 672480

C1 6601782, 671385

C2 6601760, 671350

C3 6601818, 671443

C4 6601780, 671367

D1 6600398, 674738

D2 6600451, 674879

D3 6600510, 674946

D4 6600483, 674805

Appendix 3: Calculations of the water volume and water flow

Water volume The following formula was used to calculate the water volume inside each well:

�!"#$% = �×�!"##×�!"#$% The definition for each parameter:

�!"#$% The volume of the water in the well

�!"## The diameter of the well

�!"#$% The depth of the water

The depth of the water was determined with the formula:

�!"!"# = �!"##"$ − �!"#$%&' Where:

�!"##"$ The depth from the top of the well to the ground in the well

�!"#$%&' The depth from the top of the well to the water surface in the well

Water flow The following formula was used to calculate the water flow of each stream:

!!"#$%&"' �!"#$%& = !!"#$% The definition for each parameter:

�!"#$%& The water flow of the stream

�!"#$%&"' A measured volume of water in the stream

�!"#$% The time it took for the stick to travel trough the measured volume of water in the stream

The measured volume of the water in the stream was determined with the formula:

�!"#$%&"' = �×�×� Where: � The depth of the measured volume of water in the stream � The length of the measured volume of water in the stream � The width of the measured volume of water in the stream

Appendix 4: Laboratory results The laboratory results from the experiments that were executed to determine the chloride concentration, the alkalinity and the CODMn of the water samples are illustrated in the table below. The consumed amount of titrant used for each method on the water samples is shown in the table.

Water sample Determination of the Determination of the Determination of the chloride alkalinity CODMn concentration

Consumed amount of Consumed amount of Consumed amount of silver nitrate hydrochloric acid potassium permanganate [ml] [ml] [drops] Tap water 6 A1 1.12 2.86 18 A3 0.42 1.75 4** B1 0.26 1.25 10 B2 2.24 2.80 18 B3 2.24 2.75 17 B4 1.66 1.65 15 B5 0.82 1.55 20 1.45* 1.50* 1.50* B6 0.52 1.45 26 0.48* 0.50* 0.53* C1 0.28 0.55 27 C2 0.30 5.40 7 D1 0.51 3.25 9 D2 0.30 3.10 3 D3 6.37 0.95 12**

*Repetitions of the titration on the sample

**Samples that were diluted from 10.0 ml to 100.0 ml for the CODMn determination

Appendix 5: Calculations for the analysis methods

Chloride concentration The chloride concentration for each water sample was calculated with the following formula:

!!"!#$!"%&×!!"#$! �!"! = !!"#$%&

The volume for the consumed amount of titrant (�!"!#$%!) was known from the lab results. The water sample volume (�!"#$%&) that was used for every water sample was 100 ml. The concentration of silver nitrate in the titrant (�!"#$!) used for the experiment was 100 mM. The chloride concentration (�!"!) could then be calculated with the formula above because the values for rest of the parameters in the formula were identified. �!"! was then multiplied by the atomic mass of chlorine, which is 35.453 g/mol, to convert the unit of the chloride concentration from millimolars [mM] to milligrams per litre [mg/l].

Alkalinity The alkalinity concentration will be calculated with the following formula:

!!"!#$%!×!!"# �!"!#$%!×�!"# = �!"#$%&×�!"# ⟹ �!"# = !!"#$%&

The volume for the consumed amount of titrant (�!"!#$%!) was known from the lab results. The water sample volume (�!"#$%&) that was used for every water sample was 10 ml. The concentration of hydrochloric acid in the titrant (�!"#) used for the experiment was 10.42 mM. The alkalinity (�!"#) could then be calculated with the formula above because the values for rest of the parameters in the formula were identified.

CODMn

Tap water contains 2.6 mg O2/l and consumes 6 drops of potassium. This was compared with the results from the experiment to calculate the CODMn value of the spring water samples.

The CODMn value was calculated with the following formula:

!!"#$%&×!!"# �!"# = !" !!"#

The number of potassium permanganate drops that were consumed by the tap water (�!"#) and water samples (�!"#$%&) were known from the lab results. The oxygen concentration of tap water (�!"#) was also known. The CODMn value of the water sample (�!"#!") could be calculated with the formula above. The number of potassium permanganate drops that were consumed by the water samples that were diluted from 10 ml to 100 ml, were multiplied with 10 before the CODMn value was calculated.

Appendix 6: Calculations for the chloride flow in Arkels tingstad The following calculations were made to study the chloride flow from the spring water and stormwater that flows through two streams in Arkels tingstad with the abbreviation B4 and B5. The reason that the chloride flow was interesting for these particular streams was because there was a road near water that flowed to both of the streams (stormwater). This could possibly increase the chloride concentration of the spring water that flowed through these streams because of road salt. There was a road near the stormwater B3, and there was a road near the water in B8. The water in B1 and B7 flows from a spring horizon.

Figure 14 Water flows in Arkels tingstad with the flows and chloride concentrations

Chloride flow from B1 and B3 to B4 Water from B1 and B3 flowed through the stream in B4. The chloride concentrations for B1, B3 and B4 were measured analytically. The water flow for B3 and B4 were measured during a field trip in Vallentuna. However, the water flow of B1 could not be measured because the water was in a well. The water flow for B1 was calculated in order to find out how much chloride flowed from B1 and B3. The percentage of chloride that flowed from B1 and B3 to B4 could then be calculated. The water flow in B1 could be determined with the following formula:

�!! + �!! = �!! ⟹ �!! = �!! − �!!

�!! The water flow of the water from B1

�!! The water flow of the water from B3

�!! The water flow of the water from B4

The water flows of B3 and B4

�!! = 0.7 �/�

�!! = 1.1 �/�

The water flow of the spring water from B1

�!! = 1.1 − 0.7 = 0.4 �/�

The following formula for the molar water flows should have been fulfilled if the calculated water flow for B1 was correct. This formula could be used to validate the calculated water flow for F1:

�!"!,!!×�!"!,!! = �!"!,!!

Where: �!"! = �!"!×� Which results to the following formula:

!!"!,!!×!!!!!!"!,!!×!!! �!"!,!!×�!! + �!"!,!!×�!! = �!"!,!!×�!! ⟹ �!"!,!! = !!!

�!"!,!! The chloride concentration for B1

�!"!,!! The chloride concentration for B3

�!"!,!! The chloride concentration for B4

The chloride concentration for B1, B3 and B4

�!"!,!! = 0.26 ��

�!"!,!! = 2.24 ��

�!"!,!! = 1.66 ��

If the calculated value for �!"!,!! is close to the value of �!"!,!! from the results, then the calculated value for �!! was correct.

Calculation of the chloride concentration for B4 !.!" ×!.!!!.!" ×!.! = 1.52 �� !.!

The value 1.52 mM is close to the value of 1.66 mM, which validates that the calculations for the water flow of B1 were correct.

Precent of water in B4 that flows from B1 and B3 ! From B1: !! ≈ 36 % !!! ! From B3: !! ≈ 64 % !!!

The molar flow of chloride The molar flow of chloride was calculated with the formula:

�!"!,!! = 0.104 ��/�

�!"!,!! = 1.568 ��/�

�!"!,!! = 1.826 ��/�

Precent of chloride in B4 that flows from B1 and B3 From B1: !!"!,!! ≈ 6 % !!"!,!! From B3: !!"!,!! ≈ 94 % !!"!,!!

Chloride flow from B7 and B8 to B5 The chloride concentration and water flow for the water in B5 were measured. The chloride concentration for the spring water in B7 was estimated to be the same as the chloride concentration for the spring water in B1 because they both flowed from the same spring horizon in Arkels tingstad. The chloride concentration for the stormwater in B8 was estimated to be the same as the chloride concentration for the stormwater in B3 because they were both located near roads.

The chloride concentration for B5, B7 and B8

�!"!,!! = 0.26 ��

�!"!,!! = 0.82 ��

�!"!,!! = 2.24 ��

The water flow for B5

�!! = 33.8 �/�

Formula for the water flows

�!! + �!! = �!! ⟹ �!! = �!! − �!!

Formula with the water flows and chloride concentrations

�!!×�!"!,!! + �!!×�!"!,!! = �!!×�!"!,!!

The two formulas above result to the formula if the first formula is inserted into the second one:

(�!! − �!!)×�!"!,!! + �!!×�!"!,!! = �!!×�!"!,!! The water flow for B8 could then be calculated.

The water flow for B8

�!! = 9.56 ≈ 9.6 �/�

The water flow of B7

�!! = �!! − �!! ⟹ �!! = 24.24 ≈ 24.2 �/�

Precent of water in B5 that flows from B7 and B8 ! From B7: !! ≈ 72 % !!! ! From B8: !! ≈ 28 % !!!

The molar flow of chloride

�!"!,!! = 27.716 ��/�

�!"!,!! = 6.3024 ��/�

�!"!,!! = 21.4144 ��/�

Precent of chloride that flows from the B7 and B8 B7: !!"!,!! ≈ 0.23 = 23 % !!"!,!! B8: !!"!,!! ≈ 0.77 = 77 % !!"!,!!

Appendix 7: Physical-chemical properties measured in the field trip The physical-chemical properties of the spring water, such as the water temperature, the pH- value and the electrical conductivity measured in the field trip with instruments, are illustrated in the table below. Olle Wahlberg gave the indecisions of the instruments used for measuring the temperature, the pH-value and the electrical conductivity of the spring waters.

Parameter Uncertainty

Water temperature ± 0.5 ℃ pH-value ± 0.2

Electrical conductivity ± 10 %

Spring Water temperature pH-value Electrical conductivity [℃] [mS/m]

A1 8.3 ± 0.5 6.6 ± 0.2 52.4 ± 6

A3 10.4 ± 0.5 7.0 ± 0.2 16.7 ± 2

B1 8.3 ± 0.5 6.5 ± 0.2 12.5 ± 2

B2 13.1 ± 0.5 7.0 ± 0.2 52.0 ± 6

B3 13.6 ± 0.5 7.0 ± 0.2 60.4 ± 7

B4 18.3 ± 0.5 6.7 ± 0.2 49.5 ± 5

B5 12.8 ± 0.5 7.4 ± 0.2 36.8 ± 4

B6 11.1 ± 0.5 7.6 ± 0.2 33.8 ± 4

C1 8.5 ± 0.5 7.0 ± 0.2 7.0 ± 1

C2 9.4 ± 0.5 6.9 ± 0.2 44.3 ± 5

D1 8.6 ± 0.5 7.4 ± 0.2 28.2 ± 3

D2 9.8 ± 0.5 7.4 ± 0.2 29.1 ± 3

D3 6.5 ± 0.5 6.3 ± 0.2 10.0 ± 1

Appendix 8: Physical-chemical properties measured with laboratory methods The physical-chemical properties of the spring waters, such as the chloride concentration, the alkalinity and the CODMn measured with laboratory methods, are illustrated in the table below. Olle Wahlberg gave the indecisions of the titrations for measuring the chloride concentration, the alkalinity and the CODMn of the spring waters. To check if the uncertainty was correct, three repetitions were made of the titration on sample B6 for determining the chloride concentration, and the results indicated that the given uncertainty was suitable for the measurement. The same was done for the titration on sample B5 for the determination of the alkalinity, and this also indicated that the given uncertainty was suitable for the measurement.

Parameter Uncertainty

Chloride concentration ± 10 %

Alkalinity ± 7 %

CODMn ± 5 %

Spring Chloride concentration Alkalinity CODMn

[mg/l] [mekv/l] [mg O2/l]

A1 39.7 ± 4.0 2.98 ± 0.21 7.8 ± 0.4

A3 14.9 ± 1.5 1.82 ± 0.13 17.3 ± 0.9

B1 9.2 ± 1.0 1.30 ± 0.20 4.3 ± 0.3

B2 79.4 ± 8.0 2.92 ± 0.21 7.8 ± 0.4

B3 79.4 ± 8.0 2.87 ± 0.21 7.4 ± 0.4

B4 58.9 ± 5.9 1.72 ± 0.13 6.5 ± 0.4

B5 29.1 ± 3.0 1.56 ± 0.11 8.7 ± 0.5

B6 18.4 ± 1.9 1.51 ± 0.11 11.3 ± 0.6

C1 9.9 ± 1.0 0.57 ± 0.04 11.7 ± 0.6

C2 10.6 ± 1.1 5.63 ± 0.40 3.0 ± 0.2

D1 18.1 ± 1.9 3.39 ± 0.24 3.9 ± 0.2

D2 10.6 ± 1.1 3.23 ± 0.23 1.3 ± 0.1

D3 225.8 ± 22.6 1.00 ± 0.07 52.0 ± 2.6

Appendix 9: Sensory properties of the water samples The sensory properties that were examined of each spring water sample are described in the table below. The taste for various springs could not be examined because they looked too contaminated to drink.

Spring Odour Taste Colour Clarity Precipitate

A1 Faint soil smell Pleasant with an Colourless Clear Coarse organic after-taste particles

A3 Very faint smell Faint humus taste Brown, quite Colloidal Brown/grey with a strong turbid particles, mud precipitate after-taste

B1 Very faint smell Good taste Colourless Clear Brown precipitate

B2 Distinct smell Bad taste Colourless Clear Brown precipitate

B3 Distinct smell Bad taste Brown Clear Brown precipitate

B4 Bad smell Bad taste Brown Brown particles Brown precipitate

B5 Faint smell Pleasant taste Brown Clear Brown precipitate

B6 Distinct and Distinct and Colourless Nearly clear Brown pleasant smell pleasant taste with precipitate a sharp after-taste

C1 Faint smell Distinct taste with Brown Clear Brown a long after-taste precipitate

C2 Faint and Good taste Colourless Clear Brown/grey pleasant smell precipitate

D1 Strong and _ Brown Clear None unpleasant smell

D2 Faint smell _ Brown Clear None

D3 Strong and _ Brown/yellow Brown particles Brown unpleasant precipitate, smell coarse particles