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 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 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 , 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, and 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 assess the suitability of the water quality in Hetlebakkstemma for recreational activities in and around the water, and the efficacy of local private treatment systems in protecting the local aquatic ecology. For this purpose, we sampled the water at different sites at Hetlebakken and analysed the different factors described previously. Results were compared to water quality standards, and trends over the last years were analysed.

5 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

2. Materials and methods

2.1 Sampling area and sites Hetlebakken is a small residential area located in Åsane, approximately 10 km north of Bergen city. Households in the area use several different ways to treat wastewater, which then ends up in the lake or in one of the many associated streams. Water quality measurements were conducted at the 9. of September 2014 in a total of six sites, of which two were in the lake and tree in streams to the north of the lake and the last one were a Biovac® cleansing system at site X (Figure 2.1).

Figure 2.1: Map of the Hetlebakk area, with sites 1 to 5 marked with red digits. Site X, a Biovac® cleansing system, is located approximately 50 metres to the south of site 3.

6 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

The lake The lake, Hetlebakkstemma, is surrounded by trees like birches and pines to the north and pastures to the west. On the east side 10 buildings lie close to the water’s edge, and wastewater is discharged from about 50 houses through three outlets. The water is clear and the bottom consists of rocks of different sizes embedded in a layer of sediments. Sites 1 and 2 lie in the main swimming area in the northern end of the lake.

Site 1 Site 1 was partly overgrown. Mats of pondweed covered some of the lake surface, and closer to land large sedges dominated as well as one species of horsetail. The land area between sites 1 and 2 was covered with grasses. On the lake bottom there was a thick layer of sediments and scattered large rocks. The samples were collected approximately 3 meters out from the shore.

Site 2 Site 2 was more open and exposed than site 1, and the water was slightly clearer. There were less bottom sediments, and more rocks, and in some places the bedrock was exposed. There was no algae growth on the rocks, and no pondweed on the water surface like in site 1. Water lobelias were present in large quantities both on land and on the lake bottom. Sedges were growing close to land, but in significantly smaller quantities than in site 1. Samples were collected 3- 4 meters from shore.

The streams As a consequence of the low precipitation this year the water level in the three sampled streams was very low. Sites 4 and 5 were situated at different parts of the same stream, so that the water from site 5 flowed towards site 4.

Site 3 This stream passed under a very muddy lawn, where roots of trees seemed to have been removed recently. This disturbance could affect the water quality. Further north from this site was a large area of wilderness. The stream water was clear, but had a faint smell. Along the water’s edge grew lots of grasses and mosses, as well as raspberry bushes, which are considered as good nutrient indicators. In the forest around the stream grew a variety of trees: Birch, pine, spruce, grey alder and rowan.

7 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Site 4 This stream was located about 7 meters away from the road. Outside the closest house there was some exposed soil, possibly as a result of the construction of a lawn. This might have caused runoff that could affect our results. Wastewater from approximately ten houses end up in this stream. The water was clear, shallow and had no noticeable smell. The vegetation around the stream was dense and varied, and rocks and trees were covered in mosses. Ash trees, large ferns and raspberry bushes indicated a nutrient rich soil. The forest around the stream was natural, dense, middle-aged and dominated by pine and birch trees.

Site 5 A road was running right past this site, and a cabin stood only 6-7 meters away. The bottom was covered in gravel and small rocks, with areas of mud in between. A large log was lying partly into the stream. The water was sparse and slow running. The stream had a strong smell of sulphur, but the water itself looked clear.

The area around the stream was overgrown with tall grasses along the edge, trees protruding out over the stream with the consequent accumulation of leaves in the water. Mosses grew on the trees and rocks in and around the water. The presence of maple trees, large ferns, raspberry bushes and fireweed indicated a nutrient rich soil in this site as well.

Site X Samples were also taken from an access point at the output of a Biovac® wastewater treatment system that was located approximately 50 meters to the south and uphill of site 3. There seemed to be more sediments towards the bottom of the tank. In the Biovac®, chemicals are mixed with the wastewater in order to make phosphorus bind to the sludge. However, the chemical tanks attached to this system were empty. This will most likely influence the results of the water quality tests we took from this water.

8 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

2.2 Sampling and sample analysis

Temperature, conductivity and oxygen Temperature, conductivity and oxygen saturation was measured in water taken from a depth of 0.5m in the lake and at surface level in the streams and at the Biovac® wastewater treatment plant.

Samples at 0.5m depths were taken using falcon tubes attached to the far end of a ~1.5m long pole. Depth was certified using a flotation device attached by a 0.5m long string to the end of the pole. Samples were taken by submerging the falcon tube turned upside-down until the string started to tighten, it was then allowed to fill with water by being turned up again. Samples were removed carefully. Oxygen saturation was measured using a WTW Oxi 3205, and conductivity with a MultiLine® Multi 3410 IDS. The measurements are in the form of percentage of saturation, meaning that the temperature effect is taken account for in the measurement. Temperature was measured with both probes, and the mean value of the two temperatures was used. pH Water samples were taken at 0.5m depths in the lake, using the same protocol as the one for temperature/conductivity/oxygen measurements, and at surface level in the streams. They were subsequently transported on ice to the lab for measurement using a WTW pH 3110 probe. pH was also measured with pH paper in the the field.

Phosphorous samples At sites 1 to 5, two 50ml bottles of water were collected for phosphorous analyses. At site X only one 50ml bottle was sampled. At site 1 and 2 the samples were taken at 0.5m depth. At sites 3 to 5, the samples were taken at the surface. Eleven samples were delivered to Eurofins dept. Bergen. In accordance with the NS-EN ISO 6878 standard Eurofins digested the samples with persulfate in autoclave to convert more complex phosphorus species into orthophosphate before they were analyzed for levels of Total Phosphate and Orthophosphate using the continuous flow injection method, in accordance with the NS-EN ISO 15681-2 standard. The results from the analysis were compared to the standardised water quality classification by phosphorus concentration made by UK Environment Agency (table 2.1).

9 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Table 2.1: Standardised water quality classification by phosphorus concentration (UK Environment Agency, 2013).

Thermotolerant Coliform Bacteria (TCB) Samples were collected with the same methodology as before. All samples were refrigerated for a maximum of 4 hours before being delivered to Bergen Vann KF, Bergen Kommune’s water laboratory. The analytical technique used was NS 4792, a viable counting method selective for TCB (Standard Norge, 1990). The membrane filter-Fecal Coliform (m-FC) agar and temperature favour bacteria that can produce acid from lactose at high temperatures (44.5°C) (Geldreich et al, 1965). The units of measurement for analysis of this type are colony forming units (CFU)/100 ml.To find the water quality based on the TCB, a Standardised table for water quality based on the number of thermophilic coliform bacteria colonies were used (table 2.2).

10 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Table 2.2: Standardised table for water quality based on the number of thermophilic coliform bacteria colonies formed per 100 ml. (Andersen et al. 1997).

Biodiversity samples Kick samples were collected for each of the sites to assess the macrofauna diversity. For sites 3, 4 and 5, this involved holding a 1 mm meshed 10 l bucket against the current of the stream, while kicking in the bottom sediments. The kicking lasted for 1 minute at each site, and the bucket was held 0.4-0.5m from the kicker. At sites 1 and 2 the samples were taken by a person kicking while rotating on self- axis, simulating water flow (also for 1 minute). To standardize the sampling the same person took samples from site 1 and 2, while another person took samples from site 3, 4 and 5. The water flow at site 4 and 5 was so little that it was impossible to collect sediment from kick sampling by passive mean alone. Therefore, water was manually driven through the bucket to simulate flow. The biodiversity samples were assessed in the laboratory at Bergen University. All recorded fauna was determined down to lowest required level for a Biological monitoring working party (BMWP) index. Some taxa were identified to phylum while others down to family level.

11 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

2.3 Data Analysis and Statistics

Biodiversity As a measure for water quality we used the BMWP procedure (Chapman and Jackson, 1996) of scoring select invertebrate families represented in our samples in accordance to their association with varying water qualities. Both old and revised reference values were used, and both sum BMWP score and average score per taxon (ASPT) was calculated to collate the values.

Table 2.3: Quality by BMWP and ASPT scores (Ouse 2012)

Species entropy was estimated from calculation of the Shannon Index

where S is species richness and pi is the relative abundance of each species. This gives us a measure of the α-diversity within each sampled habitat.

Statistics and data management To collate and organize the data, calculate indices, means and standard deviations, and draw plots for visualization, we used Microsoft Excel and Google Sheets. No statistical tests were performed, as the data was not sufficient in size or comparability for this to be done in a rigorous manner.

12 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

3. Results

3.1: Abiotic Factors

Table 3.1 shows that temperature is higher in the lake sites, 1 and 2, than in stream sites 4 and 5. The exception is stream site 3, which is warmer than the lake sites. Site 3 also has the lowest pH of all 5 sites and by far the highest conductivity, which is of the same order as the wastewater treatment effluent at site X.

Table 3.1: Water surface temperature, pH, oxygen level and conductivity across the 6 sites around Hetlebakkstemma. Samples at 0.5m depths were taken using falcon tubes attached to the far end of a ~1.5m extension rod.

Phosphorous A large degree of variation is observable across the 5 sample sites, both between the two types of environments- lake vs stream- and between the stream sites (3-5), as can be seen in Figure 3.1. The means of the lake sites 1 (9.1µg/L) and 2 (8.9µg/L) can both be classified as ‘very low’ (Table 2.1). In fact, concentration in both site 1 (p=0.000189) and 2 (p=0.00016) is significantly lower than site 4, which has the lowest mean of the stream sites. The mean phosphate concentration at stream site 4 (51.5µg/L) is deemed ‘low’, while site 5 (540µg/L) is ‘very high’. Both site 3 (6050µg/L) and the treatment plant effluent pipe- site X (10000µg/L) - returned ‘excessively high’ concentrations.

13 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Figure 3.1: Mean phosphorus concentration (±Standard deviation(SD)) from duplicate samples at Hetlebakken sites 1-5, and a single sample at site X, displayed on a logarithmic scale. Categorisation is based on standardised water quality (UK Environment Agency, 2013).

3.2 Thermotolerant Coliform Bacteria

The TCB concentration was higher in all the stream sites than in the lake. As can be seen in Figure 3.2, the highest TCB concentration occurred at site X, with a mean of 3800 CFU/100ml. Of the environmental samples, site 3 had the highest number of colonies with a mean of 1967 CFU/100ml. This is 0.52 times the number in site X (the water from site X is discharged approximately 50 meters upstream from site 3). Site 1 had the lowest TCB concentration with <10 CFU/100ml, and site 2 had slightly higher values, with 17 CFU/100ml. Site 4 had the lowest TCB concentration of the three stream sites, with 193 CFU/100ml.

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Figure 3.2: Mean concentrations of TCB (±SD) from triplicate water samples at six sites in Hetlebakken, Norway, displayed on a logarithmic scale. Categorisation is based on standardised water quality (UK Environment Agency, 2013). The water laboratory did not provide accurate results for TCB concentrations less than 10 CFU/100ml, and these concentrations are considered as 0.

According to Table 2.2, site 1 has a ‘very good’ water quality, site 2 a ‘good’ quality, site 4 a ‘less good’ quality, site 5 falls under the category ‘bad’, and site 3 and X have a ‘very bad’ water quality.

3.3 Biodiversity The overall benthic fauna varied throughout the different sites, as shown in figure 3.3. For the total dataset, see appendix 2. Site 2 had the highest diversity among all the samples, with 9 taxa. The other lake sample, from site 1, had 7 taxa. Only 4 taxa were common to both sites. Site 3 had the highest diversity of the streams, with 8 different taxa. Site 4 had 7, while site 5 had the overall lowest number of taxa with only 5. The number of specimens from each site varied from 19 at site 1 to 410 at site 3. The most numerous groups were Oligochaeta (total of 395), Plecoptera (total of 94) and Diptera (total of 91). Of them Oligochaeta and Diptera were found at all five sites (Figure 3.3).

Site 2 had the highest Biological Monitoring working party (BMWP) score (39) (appendix 2). The lowest was site 4 with a BMWP score of 22 (appendix 2). This indicates that all the sites at

15 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Hetlebakken have poor biological quality (Table 2.3). Site 2 also had the highest ASPT score (5,6). Site 3 had the lowest score (4). The ASPT scores places sites 1, 3, 4 and 5 into a category of poor water quality, while site 2 has fair water quality (Table 2.3). Site 1 have the highest Shannon index, while site 3 have the lowest (table 3.2).

Figure 3.3: Biodiversity in larger taxonomic groups, showed in percent of total number of specimens. For exact values, see appendix 1.

Table 3.2: The shannon entropy and shannon equitability at site 1-5 at Hetlebakken 2014. Site 1 2 3 4 5 Shannon entropy (H') 1,79 1,58 0,58 1,62 1,22

3.4 Comparisons with previous years

To assess how conditions have changed over time, and whether our data was in line with previous reports, we drew together directly comparable data from multiple years (Bhurthel et al., 2010, Ceemala. et al., 2011, Løvik et al., 2013). Environmental indicators, both direct and indirect measures, we deemed relevant in building a picture of the area’s general ecological health. Data for 16 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

2011 were used from graphs when available, while the partly missing biotic data was replaced with its 2010 counterpart (Ceemala. et al., 2011, Bhurthel. et al., 2010). Data even older than this was deemed too poor for meaningful comparisons, as it was either incomplete or followed different protocols.

At the stream sites, in particular at site 3 and 5, there was a marked increase in both TCB (fig. 3.5) and phosphorus (fig. 3.4) values compared to previous years, while sites 1 and 2 showed little change. The diversity indices (fig. 3.6) are less clear, with site 3 showing a marked decrease, while the others all show roughly similar values to previous years.

Figure 3.4: Average total phosphorus concentrations (µg/l) ±1 standard deviation at five sites for three years. (Y-axis scaled logarithmically)

17 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Figure 3.5: Average TCB counts (colony forming units per 100ml) at five sites for three years ±1 standard deviation. (Y-axis scaled logarithmically)

Figure 3.6: Shannon entropy index (H’) at five sites for three years. Single sample per site per year, no measure of variability within the data.

18 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Discussion

4.1 General observations

All factors except biodiversity indicate a good water quality in the lake, although in some cases the quality is decreasing compared to previous year’s measurements. In the streams, the quality is generally poor, with very high levels of phosphorous and TCB in site 3 and 5, and slightly lower, but still concerning values in site 4, and “poor” biodiversity across all sites (Table 2.3).

The study was conducted in a dry period, and this has probably affected the results (Acuña et al. 2005). Less rain to less runoff from the surroundings, and as can be seen in figure 4.1, the runoff in the Hetlebakken area in the period of the sampling was very low compared to previous years. From this, one can expect lower levels of organic materials from the surroundings (Acuña et al., 2005). On the other hand, the low water level will lead to more accumulation of organic material in stagnant parts of the stream (Boulton & Lake, 1992), and the combination of an increase in detritus and reduced physical mixing will lead to lower concentrations of dissolved oxygen (Acuña et al., 2005). This will negatively affect the organisms with high oxygen requirements. The low water level can also lead to rapid changes in temperature (Water on the web, 2008), and according to Bunn et al. (1986), warm water and low flows can be limiting for many organisms, and can lead to increased densities of dominant organisms and low diversity. Also, when there is little runoff from the surroundings, a larger portion of the influx of water will be originating from the different treatment systems. Poor water quality could in this case indicate insufficiently treated wastewater.

The measured biodiversity in the streams indicate poor water quality, and this could be partly explained by the low precipitation in the period. This should be taken into account when comparing with previous years. However, the high values of TCB and phosphorous point to failing treatment systems. The measured biodiversity is likely to be a consequence of both factors.

19 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Figure 4.1: Rain runoff in the Hetlebakken area during the fortnight leading up to the sampling date (Senorge 2014).

There are some possible weaknesses with the methods that should be mentioned. The kick sampling is one example. If the sediments were not kicked up thoroughly enough, or if the bucket was kept too high in the water column throughout the sampling, the results may not be representative for the site. The kick sampling in the streams was problematic, as the water level was too low to get decent amounts of water through the bucket, and hence less likely to catch a representative amount of organisms. As all our biodiversity scores (apart from ASPT, appendix 2), relies upon the total abundance of organisms, this could give a lower biodiversity score than what is actually representative for the lake. Also, the difference in skills of spotting and identifying organisms within the group may have caused errors. Finally, few replicates with large variation, collected in a single day, may not be sufficient to deduce the actual conditions of the water bodies. There could also be differences in methodology between years. For example, the exact position of the sites might not be the same as previous years, which would reduce the comparability between studies. The same applies to the performing of the kick sampling and the skills in spotting and identifying organisms in the samples.

20 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

4.2 Site X appears to influence the health of Site 3

As the BioVac Sequence Batch Reactor at site X was depleted of the necessary chemicals to perform the full waste treatment process, it was predicted that phosphate measures would categorise the effluent sampled unfavourably. Site X samples returned the highest value for phosphate (10 000 μg/l), though it should be noted that this measure was based on a single sample rather than duplicates as at other sites. In the same manner, the highest site conductivity was recorded here (643 μS/cm). Conductivity is relevant as it can be elevated by the presence of high chloride, phosphate or nitrate, which are indicative of failing sewage systems (EPA, 2012). Finally, TCB values

(3800 CFU/100 ml ) were higher there than at any of the other stream or lake sites.

Site 3 is fed by the outlet from site X, as well as by runoff from the field above. Duplicate sampling here estimated phosphate levels (6 050 µg/l) second only to Site X, and falling within the same order of magnitude, unlike any other sites. The same is true of TCB scores (1967 CFU/100 ml) and conductivity (411 μS/cm) at site 3, while the temperature is higher (16.5 ℃) than at either of the other two stream sites and closer to that of site X (20 ℃). It is also important to note that low rain runoff (Figure 4.4) would not dilute the treatment plant effluent as much as it has been the case in previous years. For the same reason, this also decreases the likelihood that these aforementioned readings were the result of fertiliser runoff from the newly tilled field above the stream. Site 3 has the lowest pH (6.3) of all the sites, including site X. Humic acids are a common cause for lowered pH values, which could potentially be released and effluxed from the disturbed earth and resulted in the turbid water we observed. However, due to the sparse rainfall, this is unlikely to be the sole cause.

Taken together, our data show that the BioVac reactor, lacking the requisite chemicals, is failing to properly treat wastewater, by removing phosphorus, before release into the local environment. The similarity across all readings at Sites 3 and X imply that the poorly treated effluent in the efflux pipe is accumulating in the stream without great dilution. Macroinvertebrate populations often persist stably for years and are largely immobile, meaning monitoring the community structure over time and in comparison can identify long-term changes. These can, therefore, be used to locate sites of pollution, as may be the case here. The low Shannon biodiversity score at site 3 suggests that the treatment system has been dysfunctional for long enough to allow the ecosystem to be altered. The predominance of pollution-tolerant oligochaete worms at Site 3 suggests the ecosystem is in poor health, and the red colour of these worms is a phenomenon associated with organic pollution (Voshell, 2002).

21 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

4.3 Site 5

The stream at site 5 had, next to site 3 and X, the highest levels of phosphorus and TCB of all the sites, and also shows a sharp increase in both measures compared to previous years (fig. 3.4 and 3.5) and a corresponding decrease in biodiversity (fig. 3.6). It had also the lowest concentration of dissolved oxygen of all the sites, apart from site X. It was also by far the smallest stream, in both depth and flow rate. Based on these, and a few other factors, we feel confident to say that the stream was affected by sewage pollution. Among these additional factors, odour was the most obvious one. While there was a hint of hydrogen sulphide coming off the water, the dominant smell was a stale faecal odour often associated with septic tanks. Also lending weight to our conclusion is the weather conditions experienced leading up to and including the day we took our samples. With rainfall one expects the runoff to contribute nutrients and microbes from the topsoil and animal faeces of the terrain surrounding the streams. Conversely, with low rainfall we expect mineral and microbial contributions to originate from seepage from lower soil levels, which have relatively low concentrations of nutrients and coliform bacteria (Jobbágy and Jackson, 2001), and from potential sewage spill, which have relatively high concentrations of nutrients and coliform bacteria. The day we took our samples, and the days immediately prior, were dry. As the nutrient and microbial concentrations we found were still high compared to previous years (fig. 3.4 and 3.5), we must conclude that there is a considerable contribution from nearby sewage systems. With the limited amount of data we had the opportunity to gather it is hard to say any definitive about the level of pollution in this little stream, especially since we had no control to compare to, and the extremely low precipitation during the week leading up to our sampling, causing unpredictable systematic errors.

4.4 Site 4

Compared with previous years, we see a small increase in the TCB and phosphorus. There has been an increase the values from 2011 to 2013 and up to 2014 (Bhurthel. et al., 2010, Ceemala. et al.,

2011, Løvik et al., 2013) . Biodiversity values (Shannon’s entropy) are similar to the one measured in 2013, and much higher than the one from 2010 (Figure 3.6). The results of the samples this year might have been affected by the water level in the stream and can thus may not be very reliable. Site 4 has the lowest values of phosphorous of the three streams we tested. The TCB values at site 4 are categorized as less good (Andersen et al., 1997).

22 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Site 4 is situated downstream of Site 5 but is also affected by the outlets from 10 houses and had therefore more water than the one at site 5. With high values of TCB and phosphorus at site 5, we expected to see repercussions in the samples from site 4.. The fact that site 4 has lower values than site 5 means that the water from the tributaries is cleaner than the water from site 5. TCB values at site 5 are threefold higher than at site 4, while the phosphorus values are tenfold higher than those of site 4. A known source of error on site 4 is that site 5 was sampled before site 4. This may have an effect on the results of the samples.

The slightly elevated TCB values might be a sign of insufficiently cleaned sewage waters that come out in the stream. Still the results show that the phosphorus levels at site 4 are low and do not show any sign of phosphorus pollution. The samples at site 4 give us an inconclusive result, and more samples would be needed to give a clear conclusion. Additionally a control of the unpolluted stream is recommended, to give a better overview of the water before it comes down to the houses.

4.5 The lake sites Phosphorus and TCB measurements indicate an improvement in the water quality of the lake from 2011. The quality seems to be very similar to what it was one year ago, with a few exceptions. Based on table 3.4, the TCB concentration at site 1 has decreased markedly, moving the water quality from the category ‘good’ to ‘very good’. However, since the variance in last year’s data is quite large, one cannot say whether these values have actually changed.

The biodiversity score in site 1 has also improved slightly, but is still not close to the diversity measured in 2011 (figure 3.6). In site 2 the biodiversity score is markedly lower than both site 1 and last year’s score. The difference between site 1 and site 2 could be explained by the difference in surrounding vegetation and exposure to wastewater (Osborne & Kovacic, 1993, Kazi et al., 2009). Site 1 was the less exposed site, had a lot of vegetation in and around the water, and a sediment layer that was 35 cm deep, 27 cm deeper than the 8 cm of sediment in site 2. These conditions are better fit for a higher biodiversity than the open water and rocky bottom that was found in site 2 (Poznańska et al, 2009). Also, site 2 lies closer to the outlet pipes coming from the settlement at the east side of the lakes, possibly leading to a lower water quality than in site 1. The temperature was one degree lower in site 2 (table 3.1), which could be the cause of the slightly higher conductivity (EPA, 2012). This could also be explained by the proximity to the outlet pipes, as the wastewater could increase conductivity (EPA, 2012).

23 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

However, neither of these facts explains the reduction in biodiversity in site 2 through time. One explanation for this could simply be differences in methodology between the groups performing the research, as mentioned earlier. Another explanation could be a decrease in the quality of the wastewater discharged into the lake. This is supported by a slight increase in phosphorous and TCB concentration in site 2, but not by the decreasing levels of both factors in site 1. According to the biodiversity ASPT score, site 2 has a poor and site 1 a fair water quality. This opposes the results from the TCB and phosphorous sample. The biodiversity in the bottom sediments consisted mainly of organisms in early life stages of animals, and these are especially vulnerable to pollution (Mason, 2002), but they still respond the long-term quality of the water (Enviroscience 2014). TCB and phosphorous levels on the other hand, may change rapidly, for example after a large rainfall leading to runoff into the lake (Hawkes, 1998). However, to get a BMWP score representative for the lake, all major habitats should be included (Hawkes, 1998), while in this survey samples were taken from only two sites.

The results show a considerably higher water quality in the lake than in the streams. The PH is closer to neutral, the conductivity is lower, and the phosphorous level and TCB concentration is lower. This can be explained by the lake being a substantially larger water body than the streams, and therefore the different factors affecting the water quality have less impact on the water mass. The large amount of water is also likely to buffer the effect of the lack of precipitation this season.

24 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

4.6 Conclusions and recommendations

With ‘very low’ phosphorous levels and TCB levels indicating a ‘good’ and ‘very good’ water quality, our results do not question the use of the lake as a bathing area, as it has been concluded for the last several years. However, the decrease in biodiversity along with the slight increase in phosphorous and TCB concentrations can be a cause of concern, and it is advisable to continue the regular monitoring of these factors to ensure that this is not an increasing trend that will eventually make the lake unsuitable for recreational purposes.

The water in the streams was not of sufficient quality. All the streams had high values of thermotolerant coliform bacteria (TCB), and sites 5 and 3 yielded high values of phosphorus. At site 5, we would recommend closer inspection, in order to find the source of the high values in this stream. The Biovac reactor at site X seems to be insufficient in treating the wastewater from the houses around the site, or is not receiving the required maintenance for it to function correctly. As site 3 collects runoff from the site X Biovac reactor, the consequences can be seen immediately. The reactor has now been non-functional for the second year in a row, albeit for different reasons. Whether this is a result of technical faults or a lack of administrative attention, new systems or routines should be developed to make sure that this residential area remains conducive for play and other recreational activities.

25 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

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28 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Appendix

Appendix 1

29 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price Hetlebakkstemma 2014

Appendix 2 Distribution of the benthic fauna found at the five different sites at Hetlebakken 2014.

30 BIO300 UiB Group 8: Sigrid Skrivervik Bruvoll, Kjetil Farsund Fossheim, Aksel Anker Henriksen, Alexander Price