PROFESSEURS :
Sandra FOCARDI : giotto.ulivi@dada.it
ELEVES :
Students of 15-18 years

PLAN
CHEMICAL AND BIOLOGICAL MONITORAGGIO" OF STREAMS
A.S. 1999-2000
HIGH SCHOOL: GIOTTO ULIVI - BORGO SAN LORENZO- FIRENZE

INTRODUCTION

The job has been carried out by the classes 2° B and 3° B of the section of experimental sciences of the Giotto Ulivi high school, in the months of April-May of the year 2000.
Purpose of the present job is acquiring chemical- physical-biological data of the streams to elaborate a quality map of the waters in the territory of the Mugello. Main objective of the job is involving the students in a first hand experience job, training them in laboratory practice aimed to an environmental study and in the following elaboration of data and layout of a final report.

JOB PLAN

1. Territory
1.a Introduction
1.b Choice of the stream and geographical location

2 Biomonitoring
2.a Introduction
2.b E:B:I: method
2.c Macroinvertebrates

3 Chemical-physical parametres

4 Materials and methods

5 Results

6 Conclusion

TERRITORY

Introduction

The present physical and morphological conformation of the Mugello Valley is the result of the geological and tectonics evolution of the Appennini range and has been affected by climatic variations (glacial and interglacials periods of the Quaternary era). Such changes have affected the erosive agents and their intensity.
Also human presence has contribued and contributes to the evolution of the environmental features. Man appeared in the Mugello Valley in the middle Palaeolithic period with groups of nomadic hunters. The weight of his presence on the territory, has been felt when stable installations were created , with basically agricoltural economy (installation dating to the age of Copper and Bronze). From that moment on the practices of exploitation of the territory have modified it substantially up to the present order.
In the territory of the Mugello three different geomorphological units are recognizable.
The differences are due to morphogenetical processes, morphological dynamics (intensity and speed with which the morphological variations in the territory take place) and shapes:
1-RELIEFS
2-THE OLD LACUSTRINE BASIN
3-INTERMONTANE VALLEYS

1- They occupy a large part of the territory; they coincide with the southern dorsal- Montegiovi, Montesenario, Calvana- and the Appennini watershed to North between Citerna Mountain and Falterona. The shaping of the landscape is due to the progressive incision of the streams that come down and that confer uneven morphology with high pitched crests and steep slopes alternate to narrows and deep valleys.
2- It coincides with Mugello valley : the upper- middle part of the present basin of the Sieve up to Contea. It is a complex unit, with alternate hilly reliefs, valley flats and old terraced areas. The shaping of this zone is due to the chartered waters and to the slope processes: landslides of glide and superficial erosion with relatively slow morphological dynamics.
Areas with hilly morphology in the Appennini range - valley of Firenzuola- with argillaceous prevalence characterized by intense phenomena of disarrangement. In fact they are notably degraded areas with slopped stability problems and frequent landslides ( collapse and glide). Considering the biological(vegetation and fauna) and anthropic (use of the ground) components, we could decompose the three geomorphological units into landscape unit, each characterized from homogeneous habitat for determined physical-biological features.

Choice of the stream

Our researh has been addressed toward the Faltona stream, right tributary of Sieve river. The course of water derives from the artificial pond Piantamalanni (536 m s.l.m.) and elapses for the almost totality of his journey, parallel to 302 Brisighellese -Ravennate state street and reaches the Sieve at Canicce farm.(196 m s.l.m.). In its way it crosses the inhabitated areas of Polcanto, Poggiolo and Faltona. The two thirds of the river bed present arather uneven morphology, in a narrow valley with slopes covered by mixed woods of oaks such as black alder , haphornbeam and willows.
In the choice of the sites the following points have been taken in consideration
a-presence of infrastructuresand inhabitated nucleuses;
b-morphology of the sream: width of the river bed, maximum depth, uneveness of the bottom;
c-distance of the point of survey from the source;
d- type of riparian vegetation;

BIOMONITORING

Introduction

Biomonitoring consists of the use of species or groups of species of plants or animals to evaluate the impact of huaman activities on the environment. It is based on a simple concept: a toxic substance is harmfull to living organisms as a definition; The methodology is therefore based on the presence and distribution of the living beings in a specific environment. An effective biomonitoring methodology must be able to clearly identify the effects of human activities, to separate it from those of the environmental nature effects such as the distribution of the species of living organisms in relationship to the characteristic physical variations of the environment (altitude, ground, climate etc.). A bioindicator doesn't generally supply indications on the kind of polluting substance nor the cause of pollution, but nevertheless it presents the following advantages:
1- It provides informations not tied up to particular moments, being constantly in the environment; it suffers from the effect of the polluting factors and we are allowed to evaluate even when its cause is no more present.
2- It makes possible the evaluation of synergical effects due to the presents of more than a single polluting substance.
3- It helps to find the presence of toxic substances even in very small concentration; the effects could be direct or due to bioaccumulation phenomena in the food
4- chain.
5- It provides biological effective answers, thus resulting indicator of the environmental quality.

Not all the organisms can be use as bioindicators; typical qualities of a living organism used as a bioindicator are as follows:
1- tested sensitivity to harmfull substances;
2- wide and uniform spreading in the environment;
3- scarce mobility;
4- poliannual biological cycle;
5- knowledge of the territorial distribution of the organisms and of its relationship with life environment;
6- bioaccumulation capacity

THE E.B.I. METHODOLOGY

The E.B.I. methodology (Extented Biotic Index) is the most used one in Italy and it is based on the sensitivity to pollutants shown by some faunistic groups and on the biological variability inside the macroinvertebrates comunity. We must evaluate the presence of bentonic organisms, i.e. organisms living at the bottom of streams. Methodology is based on the attribution of numerical conventional indexes determining a score ( sistematic units amount) through which the water quality can be classified. The E.B.I. index can be calculated according to the following chart:

Example: in our analysis 10 Systematic Unities have been sampled two of wich belonging to Plecoptera, the most sensitive organisms to pollution. Plecoptera represent the chart entry line (the first in our case); such entrance is of qualitative type while the second (represented with a column) is of quantitative type and takes into account the amount of the Community Systematic Unities. The index value is drawn in the box created by the meeting of the two entrances. In the example the index value is 8 and corresponds to the class of II - Quality environment with moderate symptoms of pollution or alteration (green is the reference colour).

MACROINVERTEBRATES

Belonging organisms to different Phyla and observable to naked eye. They could be: Gasteropods, Crustacea, Oligochaeta, Hirudinea, etc. but above all bugs. The latter are represented by various orders: Plecoptera, Ephemeroptera, Odonata, Diptera, Coleoptera, Tricoptera, etc.
The bugs that live the river bottoms, present morphological adaptations that allow them not to be dragged by the water flow and so, (1) the early stadiums of the Plecoptera or Ephemeroptera present a dorsoventrally flattened body, (2) some dipteral larvas have systems such as suckers, thorns etc. for the anchorage to the substratum, (3) some Tricoptera are provided with involucra to contain larvas so making them heavier.

PHYSICAL-CHEMICAL PARAMETERS

PHYSICAL PARAMETERS

FLOW RATE
Water volume that crosses a perpendicular section of the stream direction in a specific point of the river bed using m3/s as unit.

CURRENT SPEED
It depends on the riverbed slope and depth. It identifies the stream capacity of transport. Solid materials of the riverbed present a hangover speed limit (Wa), if the current speed exceeds the speed limit, the material is transported by the river. We have top speed in yhe center of the riverbed. Speed influences even:

1. the quantity of dissolved oxygen;
2. temperature;
3. turbidity;
4. nutrients circulation.
5.

OUTFLOW COEFFICIENT
Ratio between the volume of drained off water and volume of the water fallen in a year. Relieves are made at the river mouth and it is always lower than 1.

REGIMEN
Determined by the increment of the river outflow rate in a year.

TEMPERATURE
Presents vertical and horizontal variations. In the fast and shallow rivers it doesn't present significative increment of lapse rate. In the big rivers it presents a vertical lapse rate. Surface temperature is affected by the outside weater conditions.

CHEMICAL PARAMETERS

ACIDITY - pH
The natural waters present a pH range 6 - 8.5. Such conditions are favourable to the life of most of the living organism. Variations in pH indicate presence of strong acids/weak bases salts or presence of weak acids/strong bases salts (acid and alcaline hydrolysis).

HARDNESS
It expresses the water power to make soaps precipitate total hardness is the concentration of calcium and magnesium salts present in the water. It is expressed either in CaCO3 mg/l or "French Degrees" (1° = 10 mg/l CaCO3).

NITRATES, NITRITES and NH4+
Such anions originate mainly from the agricoltural activity and the mineralization of organic nitrogen.

OXYGEN
Important element for the living community and one of basic importance in the determination of the faunistic component. There is plenty of it in running and cold waters. The amount of dissolved oxygen indicates the pollution level in a watercourse.
The pollution level in a waterause. The pullution level comes to be determined by 2 parameters: B.O.D. and C.O.D. B.O.D. (Biological Oxygen Demand): it determines the biological demand of oxygen of the defradator heterotroph microorganisms playing an important past in the degradation of organic substances.
C.O.D. (Chemical Oxygen Demand): it determines the consumed oxygen amount in the chemical oxidation of organic sustances difficult to be degraded

CHLORIDES
Anions of geologiical origin present in any natural water whose mineralogical equilibrium is assured by their presence. A high concetration (>30 mg/l) of chlorides may originate problems concerning water flora survival and development.

PHOSPHATES
The mayority of such anions derives either from wat4er percolation in exceedingly fertilized agricoltural grounds or from domestic or industrial waters disposal. High concentration levels may originate eutrophication phenomena.

MATERIALS AND METHODS

Materials used for surveys in the countryside

- macroinvertebrate nets;
- collecting bowls;
- entomological tweezers;
- magnifier;
- corked PE bottles for sample transfer to laboratory;
- thermometer;
- pH - meter;
- chronometer;
- survey charts;
- systematic keys;
- metric wheel;
- graduated pole;
- gloves;
- boots.

Materials for the examination in laboratory

- optical microscope;
- Petri plates;
- AQUAKIT.

SURVEY CHART SETTING
We have predisposed a simplified chart wich takes into consideration the most important bioindicator, even considering the plan didactic importance. Students have been provided with siplified analytical keys and recognition cards of Systematic Units. Students have been divided into groups of 5 - 6 people. Any single river area has been sampled by four groups and the results compared to those elaborated by the teacher (see refernce column).

MACROINVERTEBRATES CAPTURE
The process has been carried out through the use of nets scraping off the bottom upstream, deplacing the stones on the bottom by hands or feet to make capture easier. Sometimes Students have washed stones with the water close to net mouth. The content of the net has been poured in the collecting bowls for the first identification taking out part of the material for a further observation using an optical microscope.

RESULTS

Date : 27 April 2000
Time : 10:00 a.m.
Survey station n.1 : Polcanto (404 m s.l.m.) - NW
Position : right bank
Air temperature : 16.5 °C
Water appearance : clear
Speed : 0,34 m/s
Volume : 1,96m3
Flowrate : 0,17 m3/s

Date : 05 May 2000
Time : 11:30 a.m.
Survey station n.2 : Le Canicce (196 m s.l.m.) - N
Position : right bank
Air temperature : 19.8 °C
Water appearance : clear
Speed : 5,5 m/s
Volume : 5,11m3
Flowrate : 0,4 m3/s

CHEMICAL-PHYSICAL ANALYSIS (AQUAKIT)

E.B.I. Index Survey Station n.1 -Polcanto

E.B.I. Index Survey Station n.2 - Le Canicce

CONCLUSION

The E.B.I. index value are about 1 point underrated as to reference values since students not always have succeded recignizing not enough striking species. However the values are compatible with the different environmental situations of the watercourse , even taking into account the season when the experince nas been carried out (limited demographic load in Polcanto and Faltona survey station) The result show good quality waters even downstream form the small urban conglomerates where nevertheless a dicrease in the E.B.I. index is reported. From the close observation of the best waters are those situated upstream from Polcanto survey station.
E.B.I. methodology seens to be suitable even to a didactic livel in exploratory investigations about the enviromental situation of the waters of our rivers because indexes have shown to be completely reliable. Our aim in making the student aware about pollution has been fullfilled. Students' involvement in a field investigation has been very active event if not at the same lebel for each group (as shown in diagrams and results); nevertheless they have been invoved in the job from planning data treatment.

Université de Liège