an estimation of the number of litter items during two...

Litter in Fyris River 2011 & 2012

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

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

10th 2002. The west bank, on the left, was monitored in 2011 and 2012. Courtesy by Ingemar

Nordlund and www.kanaler.arnholm.nu ; mail correspondence, 10th May 2012.

http://www.kanaler.arnholm.nu/

Litter in Fyris River 2011 & 2012 – David Landbecker

3

Contents Method ....................................................................................................................................... 3

Results ........................................................................................................................................ 3

Discussion .................................................................................................................................. 6

Miscellany .................................................................................................................................. 7

Illustration of item types and their respective percentages from year 2011 / 2012.................... 7

Method Visual inspections were performed on May 7

th

2011 and May 5th

2012. The litter was categorized

and enumerated. The ”rubbish walks” started from

the south just north of Flottsundsbron (SWEREF99

coordinates: 6630753, 649400) (figure 1). 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 (SWEREF99:6633776, 649777).

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 2011 survey

approximately 680 metres were surveyed. Due to

higher water level and larger areas waterlogged in

approximately 510 metres were surveyed in 2012.

Results The total number of objects increased from 487 in 2011 to 671 in 2012 (+38 %) in spite of the

shorter distance surveyed in 2012 (- 25 %). The largest increases and decreases of importance

were recorded for the large number categories (+ 100 % and –100 % excluded) (Table 1).

Figure 1. The ”rubbish walk” stretches

from north of Flottsundsbron to the

northern demarkation of the Campus

area.


4

Table 1. Types of litter in numbers for the 2011 and 2012 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 2011 and

about 510 metres (15 % of the 3.4 kilomters) for 2012. The west river shore was surveyed both years.

Litter Item Type (any size)

2011 Number

2012 Number

Change

Plastic and rubber litter, various kinds 164 311 + 91 %

Plastic bottles and containers 103 59 - 43 %

Styrofoam 57 127 + 123 %

Wooden boards shaped by man 39 40 + 3 %

Metall and Aluminium cans 25 31 +24 %

Plastic bags 33 26 - 21 %

Moist snuff boxes 22 22 0

Glas bottles 21 24 + 14 %

Various litter 14 17 + 21 %

Tetra Paks 3 3 0

Cigarette package 1 2 + 100 %

Lifebuoy 1 0 - 100 %

Road cone 1 1 0

Plastic chair 1 1 0

Outboard engine 1 0 - 100 %

Cooling box 1 1 0

Car wheel 1 0 - 100 %

Fender 0 1 -1 Hard plastic mat 0 2 -1 Cigarette ends 0 2 -1 Thermos 0 1 -1 Light bulb 0 1 -1 Total number of items 487 671 + 38 %

1 The percentage concept carries no meaning when starting value is zero.


5

163

103

57

39 25 33

22

21 14 3

1

1

1

1

1

1

1

6

2a. Year 2011 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

311

59

127

40

31

26

22 24

17

3 2

0

1 1 0 1

0 1 1 2

1 1

2b. Year 2012 Litter Item Categories River Fyris, Numbers,

N=671 Plastic and rubber litter, various kinds


Styrofoam



Plastic bags

Moist snuff boxes

Glas bottles

Various litter

Tetra Paks

Cigarette package

Lifebuoy

Road cone

Plastic chair


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 2011(a) and 2012 (b). The results emanate from the effective length surveyed of about 680 metres (20 % of the 3.4 kilometer

total length) for 2011 and about 510 metres (15 % of the 3.4 kilomters) for 2012. Area (diameter ratio 100:118) of the charts

correspond to number of items.


6

Comments on Litter item types in table 1 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 2011 and 15 % (510

metres) in 2012.

Discussion

Items were measured by number and no measurements of volume or mass were performed.

The consequence may be that one litter piece from 2011 very well could be counted as two or

more in 2012 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 (2011) 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 2011 only few items were found in the water. In 2012 at least 10 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 2011 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 2011 than

results in table 1 for one river shore. If the other river shore is included as well the factor

should be 10 for the 2011 survey. For the 2012 survey the factors would be

and


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, 23rd

September 2011) 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 2012.

Water level seemed slightly higher in 2012 compared to 2011, hence the shorter length

surveyed in 2012. Flood meter readings from the www.fyris-on-line.nu site points in this

direction. The water level at Islandsfallet was slightly higher in 2012 (0.45 meter) than in

2011 (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 2011 were difficult to

reach using ordinary shoes due to the temporary wetland in 2012.

Miscellany

One bottle, from the 2011 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 2011 a rower

told me.

Illustration of item types and their respective percentages from year

2011 / 2012 Photographs are not from the actual inspection. They are retrived from the

internet.

Plastic and rubber litter, various kinds

34 % / 46 %

http://www.fyris-on-line.nu/


8


21 % / 9 %

Styrofoam

12 % / 19 %


9

Plastic bags

7 % / 4 %


5 % / 5 %


8 % / 6%


10

Moist snuff boxes

5 % / 3 %

Glass bottles

4 % / 4 %

Various litter

3 % / 3 %


11

Tetra Paks

1 % / 0.5 %

Cigarette packages

0.2 % / 0.3 %


12

Plastic chair

0.2 % / 0.2 %

Road cone

0.2 % / 0.2 %

Life buoy

0.2 % / 0 %


13

Cooling box

0.2 % / 0.2 %


0.2 % / 0 %

Car wheel

0.2 % / 0 %


14

Fender

0 % / 0.2 %

Cigarette ends

0 % / 0.3 %

Hard plastic mat

0 % / 0.2 %


15

End of report

Thermos

0 % / 0.2 %

Light bulb

0 % / 0,2 %


16

an estimation of the number of litter items during two...

Documents