Biomonitoring of water quality by the BISEL Biotic Index

The BISEL abbreviation is derived from the English expression: Biotic Index for Secondary Level, because it was designed for secondary schools. It was elaborated in the UK, in France and Belgium, where under name „Belgian Biotic Index“(BBI) is now used as the standardized method for evaluation of water quality. For its right use knowledge of 16 indicator groups of macro - water invertebrates is sufficient. These macro-invertebrates can be identified by a simple Key for identification of water macro – invertebrates.
Sensitivity of macro-invertebrates is rated from 1-7 (1- the most sensitive on water pollution, 7 – the least sensitive group on water pollution).

The Biotic Index is then derived from the standard tablet for the BISEL Biotic Index, which belongs to the manual. Final value of the Biotic Index shows biological quality of the evaluated portion of the river on the basis of occurrence of water invertebrates in that portion of the river. This quality index is comparable with water – quality classes obtained by chemical analysis of basic chemical parameters of water in the same portion of the river.

Value of the BISEL Biotic Index is a number between 0 and 10. Biotic index 0 means practically dead water, with no macro-invertebrates; other values of the Biotic Index are evaluated as follows:
Biotic Index 2-1 water quality class V very heavy pollution level
Biotic Index 4-3 water quality class IV critical condition!!! Strong pollution
Biotic Index 6-5 water quality class III medium level of pollution
Biotic Index 8-7 water quality class II low pollution
Biotic Index 10-9 water quality class I very low or no pollution

Equipment for sampling macroinvertebrates:
1.Hand net - one per group of students;
2.Large and small laboratory trays
3.Tweezers or pincers to pick up out some of the animals from the sediment, which need to be kept alive for identification and observation.

Equipment for filling out record sheets:
1.Record sheets (one per group of students per sampling point).
2.Clipboards the size of an A4 paper consisting of a tin sheet of hardboard, a clip and a sheet of transparent plastic to protect it from rain.
3.Non water-soluble writing material such as fine tipped permanent markers or pencils. 
4.One topographical map.

Equipment for identifying:
1.Stereoscopic microscopes or magnifying glasses
2.Petri dishes to identify the animals under the microscope.
3.Notebooks for writing down the identifications and semi-quantitative data.
4.Identification keys for each group of students.

Equipment for calculating the BISEL Biotic Index:
1.Compilation sheet and the biotic index.

Processing of samples:
2.Fill out the record sheet: name of the river/lake, sampling site, date, hour, your name(s).
3.Put on the boots and gloves and fill one large and two small laboratory trays about half-full with water from the brook, standing on the bank (in order not to cloud the water already).
4.Catch as many water animals as possible with the handnet. To examine the deep parts of the river, one person puts on the waders. Every time, empty the net in the large laboratory tray, including parts of plants, little stones, mud, etc...
5.Catch the animals in the large laboratory tray with a small aquarium net, a spoon or a pipette - depending on their size - and move them into the first small laboratory tray until there is at least one specimen of each kind present in this tray. Pay special attention to animals that hide themselves in or on parts of plants, stones, mud (use a tweezers) ...
6.When you cannot find new kinds of animals in the large laboratory tray anymore, catch, with a spoon or a pipette, at least one specimen of each kind of macroinvertebrate in the first small laboratory tray and move it into the vessel with the cap magnifying glass. Screw the cap.
7.Identify the animal(s) by means of the cap magnifying glass. Start with the identification key card. On this basis, you will get a first idea of the different forms of the water fauna classified up to a level higher than the family (phylum, classis or ordo).
8.Go on identifying up to the level of the family, the genus or the species, making use of the available identification keys.
9.Note the taxa found on a record sheet. Note whether you have found one or more individuals of these animals.
10.Empty the vessel with the cap magnifying glass in the second small laboratory tray and identify another kind of macroinvertebrate in the first small laboratory tray (steps 5-9).
After identification of all kinds of macroinvertebrates, empty all laboratory trays in the river/lake.