Hetlebakkstemma 2014 Water quality at Hetlebakken; River health and suitability of the lake for recreational use Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price BIO300 Autumn 2014 1 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014 Content 1. Introduction ......................................................................................................................................... 3 2. Materials and methods ....................................................................................................................... 6 2.1 Sampling area and sites ................................................................................................................. 6 2.2 Sampling and sample analysis ....................................................................................................... 9 2.3 Data Analysis and Statistics ......................................................................................................... 12 3. Results ............................................................................................................................................... 13 3.1: Abiotic Factors ............................................................................................................................ 13 3.2 Thermotolerant Coliform Bacteria .............................................................................................. 14 3.3 Biodiversity .................................................................................................................................. 15 3.4 Comparisons with previous years ............................................................................................... 16 Discussion .............................................................................................................................................. 19 4.1 General observations .................................................................................................................. 19 4.2 Site X appears to influence the health of Site 3 .......................................................................... 21 4.3 Site 5 ............................................................................................................................................ 22 4.4 Site 4 ............................................................................................................................................ 22 4.5 The lake sites ............................................................................................................................... 23 4.6 Conclusions and recommendations ............................................................................................ 25 References ............................................................................................................................................. 26 Appendix ................................................................................................................................................ 29 2 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014 1. Introduction Sustaining good water quality in freshwater systems is an important prerequisite for health and wellbeing of humans as well as for the surrounding ecosystems. With a rapidly increasing human population and simultaneously growing demands and consumption, this task becomes more and more a human responsibility, as nature can often no longer filter our waste effectively. Water quality-related diseases remain a key issue in many areas of the globe, accounting for 4% of the global burden of diseases and around 2 million deaths annually (WHO, 2014). While the overwhelming majority of cases occur in developing countries, the clear danger of contact with untreated wastewater should prompt vigilance in all situations. Several factors can be tested to get a good estimation of water quality in lake and streams. They can be biological, chemical or physical. The biological factors measured in this study were thermotolerant coliform bacteria (TCB) and biodiversity. The physical factors measured were PH, conductivity, temperature, river/lake size measurements and sediment depth. Lastly, the chemical factors, O2 and phosphorus concentrations, were also measured. The concentration of thermotolerant coliform bacteria is used as an indicator for contaminated water. These are bacteria that can lead to illness in humans and animals. Thermotolerant coliform bacteria like Escherichia coli can survive for some time in open water bodies, but cannot reproduce there (Paruch and Mæhlum, 2011). Therefore any occurrence of these bacteria is a safe indicator of faecal contamination, either from the local sewage system, or from the modest number of small farms that also lie in the area. Fresh faeces can also contain other sources of contagion. It is important to know if contamination is present and therefore it is necessary to test for E. coli in water samples (Folkehelseinstituttet, 2014). The biodiversity of macro-invertebrates is a good indicator, as some of the freshwater macro- invertebrates are very sensitive to alterations of their local environment. Changes in water quality are known to shape the composition of species and allow some taxa to dominate (Hill, 2005). The pH of a freshwater body can be affected in a number of ways. Naturally it can increase due to decomposition of organic material, or decrease due to increased algal activity. Artificially, it can be decreased by acid rain, caused by atmospheric sulphur and nitrogen oxides originating from the burning of fossil fuels. How increased acidity affects a lake depends a lot on the soil and geological characteristics in the surrounding area. High levels of easily dissolvable carbonates in the ground can work as an effective buffer. While extreme deviations from a neutral pH in either direction is 3 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014 detrimental to most forms of life, lowered levels are a more common problem. It is not only the acidity in itself which can affect life in lakes and streams, but also the fact that a low pH could lead to leaching of metals from the ground, particularly aluminium, which is of great concern for humans and animals alike (Geir Helge Johansen et al., 1992). Conductivity is a measure of how well water conducts a current, and is affected by the concentration of dissolved inorganic ions, like chloride, calcium and magnesium in the water. Soils made out of soft sedimentary rock contribute to high conductivity, while hard igneous bedrocks contribute little. Industrial pollution, urban runoff and road salting can cause increased conductivity, as can longer dry spells, because of higher ionic strength due to the evaporation of water (Lower Colorado River Authority (LCRA), 2012). Measuring conductivity is important because aquatic biota has specific salinity tolerance levels (CWT, 2004 ). Sufficient levels of dissolved oxygen are of critical importance to aquatic life. Oxygen is produced by plants and algae through photosynthesis, and consumed by most organisms through respiration. Oxygen levels decrease with depth and vary during the day (typically reaching the highest levels in the afternoon), throughout a year (with most of the photosynthesis stopping in the winter), and with temperature (with warmer waters being less able to hold dissolved oxygen) (LCRA, 2012). Phosphorous is one of the limiting factors when it comes to growth of plants and animals, as it is an important building block of genetic material and ATP (Reece and Campbell, 2011). In aquatic ecosystems, this limitation becomes apparent in algal growth. Too much phosphorus input in the water from sewage or agriculture can lead to an algal bloom, which in turn can lead to oxygen depletion, fish death and disease in humans (Knarrum, 2013). Hetlebakken is a residential area north of Bergen. In the 1980’s, the water municipality had no control of this area. People were living permanently in their cabins, and usually used septic tanks to deal with their wastewaters. Today, discharge permits are rarely given close to the lake. Further north the situation is different, as water discharged will flow into large areas of wilderness (Lars Sørfonn, personal communication). The current situation is a mix of private solutions; either shared small-scale treatment plants or septic tanks. A series of earlier studies (Hobæk 1995, 1997, 2000) concluded that the outlet from the water body was moderately polluted. Since then the water quality has been evaluated regularly. This is especially important in the lake, as residents at Hetlebakken use this site for recreational purposes. A factsheet map compiled by Bergen municipality also indicates that the water quality around Hetlebakkstemma is of poor quality, according to the EU Water Framework Directive (Grønn etat, 2009). The same map 4 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014 also shows that the area around Hetlebakken has an important biological diversity. By 2021, the municipality aim to reach a status of good water quality in accordance with the Water Framework Directive in Norway (Grønn etat, 2009). In this study, our primary focus is to