• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Environmental sciences Lab-2(Stream Pollution)

Free essay example:

Evs lab-2

Stream Study

Aim: To test a river at different locations to assess pollution levels.

Focused aim: To investigate pollution level of the river using bio indicators in the form of insects & dissolved oxygen.


Control variable: Number of sites

Dependant variable:Amount of insects, Level of pollution

Independent variable: Temperature, pH level, dissolved oxygen & turbidity of the stream


  • Dissolved oxygen meter
  • Digital thermometer
  • Plastic Bowl
  • Small Plastic cups
  • Net
  • Plastic box
  • pH paper


  • Each site will have different Stream Pollution Index
  • Each site will have different dissolved oxygen levels
  • Temperature & pH levels for each site will remain constant

Risk assessment:

  • Since we were studying the pollution levels of the stream & using insects as an indicator, there was an added risk that Insects might have been harmful to the human body. Hence contact with insects is not recommended.
  • Since current levels are high, any footwear in the stream such as flip-flops is not recommended.
  • Stones are wet & slippery, therefore rubber boots are recommended.


  • First each site was marked in order to start the experiment.
  • Stream was divided into 5 sites in order to analyse the stream pollution index of the stream carefully & accurately.
  • For each site(1-5), Insects were searched & caught by a Net.
  • Insects were then placed in a bowl of water in order to identify the species.
  • Turbidity of the stream was discovered.
  • pH level of the stream was discovered
  • Temperature of the stream was discovered
  • Dissolved oxygen for each site was measured using a dissolved oxygen meter
  • Insects were inputted in a table according to their Sensitivity rating, weight factor, Tolerance level & Number of Insects.
  • Stream pollution Index of the stream was then calculated.

Data collection & processing:

  • Ph of water on each site :7.6
  • Temperature: 17.1
  • Turbidity: 0
  • Site 1:1 Larva
  • Site 2:1 water strider
  • Site 3:1 water strider

              1 fish tadpole

  • Site 4:1 Larva

              1 water strider

              1 Needle bug

  • Site 5: 2 dragonfly nymph





Bug Type

Sensitivity Rating

Number of bugs found

Weight Factor

Column A    X Column C

Tolerant Bugs

Water Stider





Dragonfly Nymph





Needle Bug





Very Tolerant Bugs









Stream Pollution Index: Total of column D

                                          Total of column C                                                                                    


                                           =3.4,which is fair.

Stream Pollution index for each site:


Site 1

Site 2

Site 3

Site 4

Site 5



(Water Strider)

(Water strider)

(Larva, Water strider, water scorpion)

(Dragonfly Nymph)

Stream Pollution Index (SPI)







  Dissolved oxygen level(mg/l)

Site 1

Site 2

Site 3

Site 4

Site 5






Average Dissolved oxygen: 2.96



Based on the data above, We can observe that the stream pollution index gives a value of 3.4 which is fair,however in some sites while quality of water was just reaching a good level while in some sites quality of water was poor. Average dissolved oxygen for the stream was 2.96 which is harmful to aquatic life.


From our research & findings on this experiment we have discovered that the Stream Quality rating was fair, However dissolved oxygen is not suitable to aquatic life, obviously where dissolved oxygen is less than 3 it is harmful to aquatic life and were only seeing bugs that live on top of the water like the water strider on sites were dissolved oxygen was less than 3 and not finding other fishes at various sites. However this experiment could have been performed more accurately if :

  • By widening our time scale, for instance if we could have performed the tests at 3 different points in the day. To see whether if different dissolved oxygen levels would have been obtained & to see if there were any movement in the aquatic life.
  • By increasing the size of the nets, more aquatic life could have been captured & it could have helped us determine the stream pollution index more accurately.
  • It would be interesting to come back & run the test again to see if the levels are getting worse, and determine rate of change in the Stream pollution index & Dissolved oxygen.

This student written piece of work is one of many that can be found in our International Baccalaureate Group 4 Projects section.

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Related International Baccalaureate Group 4 Projects Skills and Knowledge Essays

See our best essays

Related International Baccalaureate Group 4 Projects essays

  1. Personal project - I have chosen Human Ingenuity as my Area of Interaction because ...

    turned out to be rather hard and a lot more difficult than I expected. For example: I looked at the world record for fastest time to eat 3 soda crackers which seemed rather easy, but it was actually rather challenging as soda crackers are really salty and are hard to chew fast and swallow fast too.

  2. ITGS Portfolio Assignment #1 Improvement and use of electric cars, and its affect on ...

    EarthTalk: Isn't the interest in electric cars and plug-in hybrids going to spur increased reliance on coal as a power source? And is that really any better than gasoline/oil in terms of environmental impact? -Graham Rankin, via e-mail It's true that the advent of electric cars is not necessarily a

  1. Why is alcohol considered to be a serious problem? As many 33,000 people ...

    One of the most classic symptoms of alcohol intoxication is appendicular ataxia and this results in the uncoordinated movements of the limbs. Ataxia is why a drunken person is clumsy, will sway back and forth and often fall over. Its cause is not yet known but is probably due to

  2. EVS-Lab quadrant study

    Transects were utilized in a single area(forest) where two sites were marked to study. The 25m Transect was positioned from one site of the forest to another at two sites. A sample station was taken every 3-5 m. Several methods were implemented to collect and analyze the data- * First,

  1. Research Report Time management strategies among HKU SPACE Community College students".

    For different planning methods, there were a tendency of decreasing percentage in following the plan greater than 75%. The highest percentage was students using timetable, 50% of the students selecting this method could follow over 75% of the plan. For students using schedule and list, the percentages dropped to 25% and 10% respectively.

  2. Determine the presence of reducing sugar, protein and starch in the food products by ...

    Copper sulphate solution (Biuret: 1% CuSO4) 6. Sodium hydroxide (NaOH 10%) 1. Substances 1. Protein 2. Starch 3. Glucose 4. Milk 5. Cereal 6. Bread 7. Juice 8. Cheese 9. Apple 10. Pasta 11. Lattice 12. Meat 13. Tomato 14.

  1. Group 4 Journal. Our process was an industrial one called Aquaponics. Aquaponics is ...

    completed 2. who completed this work 3. how much effort was put into this work Aline Le: 1. Contributed to the project by observing the behaviour of the plants and plant growth in the system over the course of a 16-day period and the bacteria and nutrients being consumed or released by the plants 2.

  2. Designing a series of modern fashion accessories design collection with the theme of combining ...

    12 2. Further Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work