Litter in Fyris River 2011 & 2012

Transcription

1 Litter in Fyris River 20 & 202 An estimation of the number of litter items during two consecutive years on the banks of Fyris River South of Uppsala. This litter may be flushed out into the Mälar basin Ekoln. David Landbecker, MSc in Biology, limnologist

2 Picture on front page: The picture shows the River Fyris seen from Flottsund bridge just north of the outflow into Mälaren subbasin Ekoln. The picture was taken in the north direction on August 0 th The west bank, on the left, was monitored in 20 and 202. Courtesy by Ingemar Nordlund and ; mail correspondence, 0 th May 202.

3 Contents Method... 3 Results... 3 Discussion... 6 Miscellany... 7 Illustration of item types and their respective percentages from year 20 / Method Visual inspections were performed on May 7 th 20 and May 5 th 202. The litter was categorized and enumerated. The rubbish walks started from the south just north of Flottsundsbron (SWEREF99 coordinates: , ) (figure ). I walked northward on the west river bank and surveyed wherever possible. Along the shoreline there were obstacles such as private properties, shore wet meadows, reeds and small tree stands. Surveying was not possible in these places or in places that were waterlogged. I stopped where the SLU campus area ends, about 3 kilometres north of starting point (SWEREF99: , ). Litter that was floating in the water or lying on the bottom and lying on the west litoral (on land) within a 3 meter buffer zone (slope length, not the horisontal length) was counted. The buffer zone was measured by eye. In the 20 survey approximately 680 metres were surveyed. Due to higher water level and larger areas waterlogged in approximately 50 metres were surveyed in 202. Figure. The rubbish walk stretches from north of Flottsundsbron to the northern demarkation of the Campus area. Results The total number of objects increased from 487 in 20 to 67 in 202 (+38 %) in spite of the shorter distance surveyed in 202 (- 25 %). The largest increases and decreases of importance were recorded for the large number categories (+ 00 % and 00 % excluded) (Table ). 3

4 Table. Types of litter in numbers for the 20 and 202 monitoring respectively of River Fyris banks. The results emanate from the effective length surveyed of about 680 metres (20 % of the 3.4 kilometer total length) for 20 and about 50 metres (5 % of the 3.4 kilomters) for 202. The west river shore was surveyed both years. Litter Item Type Change (any size) Number Number Plastic and rubber litter, various kinds % Plastic bottles and containers % Styrofoam % Wooden boards shaped by man % Metall and Aluminium cans % Plastic bags % Moist snuff boxes Glas bottles % Various litter % Tetra Paks Cigarette package % Lifebuoy 0-00 % Road cone 0 Plastic chair 0 Outboard engine 0-00 % Cooling box 0 Car wheel 0-00 % Fender 0 - Hard plastic mat Cigarette ends Thermos 0 - Light bulb 0 - Total number of items % The percentage concept carries no meaning when starting value is zero. 4

5 2a. Year 20 Litter Item Type River Fyris, Numbers, N=487 Plastic and rubber litter, various kinds Plastic bottles and containers Styrofoam Wooden boards shaped by man Metall and Aluminium cans Plastic bags Moist snuff boxes Glas bottles Various litter Tetra Paks Cigarette package Lifebuoy Road cone Plastic chair Outboard motor engine Cooling box Car wheel 2b. Year 202 Litter Item Categories River Fyris, Numbers, N= Plastic and rubber litter, various kinds Plastic bottles and containers Styrofoam Wooden boards shaped by man Metall and Aluminium cans Plastic bags Moist snuff boxes Glas bottles Various litter Tetra Paks Cigarette package Lifebuoy Road cone Plastic chair Outboard motor engine Cooling box Car wheel Fender Hard plastic mat Cigarette ends Thermos Light bulb Figure 2ab. Pie chart showing number fractions of litter items in River Fyris from surveys of mostly the same portions of the shore line in 20(a) and 202 (b). The results emanate from the effective length surveyed of about 680 metres (20 % of the 3.4 kilometer total length) for 20 and about 50 metres (5 % of the 3.4 kilomters) for 202. Area (diameter ratio 00:8) of the charts correspond to number of items. 5

6 Comments on Litter item types in table and figure 2 Plastic and rubber litter, various kinds are all parts and sizes and plastic and rubber possibly tore down or broken that are not included in other types. Food-stuff cover is also included. Styrofoam is frigolit in Sw. Various litter contains, e.g. lighters, tennisball, toy gun, toy spade and shoes. Life buoy, road cone, plastic chair, outbord engine, cooling box, fender, hard plastic mat, cigarette ends, thermos and light bulb were all so aberrant that they were given a type each. Length of river shore surveyed The length of the shore between starting point and end point is about 3.4 kilometers. Of this length approximately 20 % (680 metres) was actually surveyed in 20 and 5 % (50 metres) in 202. Discussion Items were measured by number and no measurements of volume or mass were performed. The consequence may be that one litter piece from 20 very well could be counted as two or more in 202 if a force is applied to it. This easily happens with for example Styrofoam if a biped or a quadruped steps on it. Only items visible or partly visible to the eye were counted. Items that were partially buried were hence counted such as the outboard engine (20) and some plastic bottles (both years). This means the true number of litter could be higher since litter items likely are covered in the shore sediment. No moving of vegetation or digging to find more items was performed. However, surveying took place before full verdure for both years. At both occasions the rubbish walk took two hours (± 5 minutes). Walking the same distance would take less than 40 minutes (walking speed 5 km/h) which illustrates the swiftness of the method described. During 20 only few items were found in the water. In 202 at least 0 items were found floating in the litoral or close to jetties and one to two items on bottom. I saw no drifting debris or litter in either years. In creeks the litter had clustered. I found two such places in 20 and I approximated the small litter in tens or fives instead of counting them individually. Some other bays were empty of litter probably due to hydrodynamic reasons. Navigation marks, concrete bridges and jetties were not included as long as they were part of an infrastructure and not broken into pieces. True amount of litter If the litter abundance is to be generalized over the whole length (i.e. area since there was a 3 meter buffer zone) the amount of litter would be five times greater for the year 20 than results in table for one river shore. If the other river shore is included as well the factor should be 0 for the 20 survey. For the 202 survey the factors would be and 6

7 respectively. The prerequisite for this is that the litter abundance is equally distributed. We cannot say it is: I can only speculate about the litter densities of the shore length that was not surveyed. There are a lot of factors impacting clustering and discovery points of litter: hydrodynamics, properties of material and chance events (e.g. items beeing picked up or moved by mammals, including man, or birds). Sources of error During the making of the story in Upsala Nya Tidning (article, 23 rd September 20) I presented the litter to the photographer and the reporter and removed the displayed items from site. This removal may have decreased the amount of litter in 202. Water level seemed slightly higher in 202 compared to 20, hence the shorter length surveyed in 202. Flood meter readings from the site points in this direction. The water level at Islandsfallet was slightly higher in 202 (0.45 meter) than in 20 (0.38 meter). Perhaps this indicates that the water was higher 4 7 kilometers downstream. Some stretches of the shoreline I was able to access in 20 were difficult to reach using ordinary shoes due to the temporary wetland in 202. Miscellany One bottle, from the 20 survey, with two enclosed messages was found. Both messages were dated 2003 and written by two at the time eleven year old girls. At least one beaver (Fiber castor) has been seen in the River Fyris during spring 20 a rower told me. Illustration of item types and their respective percentages from year 20 / 202 Photographs are not from the actual inspection. They are retrived from the internet. Plastic and rubber litter, various kinds 34 % / 46 % 7

8 Plastic bottles and containers 2 % / 9 % Styrofoam 2 % / 9 % 8

9 Wooden boards shaped by man 8 % / 6% Metall and Aluminium cans 5 % / 5 % Plastic bags 7 % / 4 % 9

10 Moist snuff boxes 5 % / 3 % Glass bottles 4 % / 4 % Various litter 3 % / 3 % 0

11 Tetra Paks % / 0.5 % Cigarette packages 0.2 % / 0.3 %

12 Life buoy 0.2 % / 0 % Road cone 0.2 % / 0.2 % Plastic chair 0.2 % / 0.2 % 2

13 Outboard motor engine 0.2 % / 0 % Cooling box 0.2 % / 0.2 % Car wheel 0.2 % / 0 % 3

14 Fender 0 % / 0.2 % Hard plastic mat 0 % / 0.2 % Cigarette ends 0 % / 0.3 % 4

15 Thermos 0 % / 0.2 % Light bulb 0 % / 0,2 % End of report 5

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