1. Macroinvertebrates Macroinvertebrates are Biological Indicators.
They are less than a millimeter-sized bodies and therefore visible to the naked eye. Among the macroinvertebrates present in the aquatic environment we take into consideration the following groups:
• INSECT (beetles, mayflies, stoneflies, caddis flies, Diptera)
• MOLLUSCS
• SHELLFISH
• "WORMS" (cylindrical and flat)
A Biological Indicator is any organism which is able to provide information on the quality of the environment and its changes. They are mainly species susceptible to pollutants, whose disappearance indicates the presence of foreign or harmful products for the environment.

2. Why do we choose them as quality indicators of a river?
• Many species of Macroinvertebrates are sensitive to pollution.
• Their relationship with the environment of streams and rivers is well known.
• Living mainly on underlying substrates (benthic organisms) they are not subjected to continuous migrations and having life cycles lasting less than one year, they are regularly found in watercourses.
• They are sampled and classified easily.
• Fish depend on Macroinvertebrates for their food.

3. Procedures for sampling
-Tools needed for the sample:
-Procedures:
n° 1 net with handle
n° 4 trays
n° 5 bottles
n 4 tweezers
n 4 pipettes
n° 2 pairs of boots
n° 1 a working paper and a pen
n 1 a len or a stereoscope
Fill in the the working paper.
Put on boots to sample Macroinvertebrates in the riverbed using a net.
Go downstream and upstream , with your hands move rocks and sediments quickly and make sure that everything which comes out ends up in the net.
Repeat the sampling every 5 metres in 20 metres against the flowing stream.
Pour the content of the net into the trays, table 3
Classify the organisms according to their morphological characteristics (limbs, shape, size).

6. Calculation of the environmental quality class of a river:
1.Tick in the Systematic Unit column 1 (rare StoneFly species, species, etc.) each systematic unit
2. Tick in column 2 even if there are different species among the same systematic unit.
3. Sum up the total number of the living beings found in column 1.
4. At the intersection of columns and rows find the class of quality, (I to IV).
5. Read the final table of the water quality. In the columns you can find the number of the Macroinvertebrates, in the rows the categories (A,B,C,D,E) for the classification of the water quality. At the intersection of columns and rows you find the class of quality (I to IV). Class I is the best and means that the water is not contaminated while class IV is the worst and means that the water is highly polluted.

7. Table for classification

8. Final results Blue Blue-Green Green Green-Yellow Yellow Yellow-Red Red
Class of quality I
I-II II
II-III
III
III-IV IV
Judgment
Incontaminated
Not very contaminated
A little bit contaminated
Critically contaminated
Very contaminated
Heavily contaminated
Contaminated beyond measure
Cartografy colour
Blue
Blue-Green
Green
Green-Yellow
Yellow
Yellow-Red
Red

9. KIITOS!! GRAZIE!! THANKS FOR THE ATTENTION
ANDREA, ALESSANDRO, SUVI, MIRJAMI, EMILIA AND ARIANNA