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Chemical and

biological tests of

the river water

in Maeikiai

district

Maeiki MerkelioRakausko gimnazija

Chemical and biological tests of the

river water in Maeikiai district

All waters of the area belongto the Venta basin. There are about 100 rivers and

streams of different length, 16of them longer than 10 km.,with a total length of 372 km.

Larger rivers are Venta,Varduva, erkn, Vadakstis,Vieet.

The longest river is Varduvawhich runs 74.1 km. in the

area.

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Chemical and biological tests of riverswater in Maeikiai district

The landscape is enrichedby diversity, nature, ponds(there are even 57 of themwith the total area of 533hectares).

Modern hydraulicstructures are constructedon some ponds which arenear the rivers likeVarduva, erkn,Vadakstis, Ava. On theserivers small hydroelectric

power stations (Renavas,Juodeikiai, erknnai,Kulnai) are built .

Chemical and biological tests of rivers

water in Maeikiai district

The district has only six lakeswith a total area of just 432hectares.

The largest and most valuableis Plinkiai Lake (393.5hectares). Near the town Sedathere is Sedula Lake (33.1 ha).The lake is oblong, its length is2.1 km and a maximum widthonly 0.2 km.

Other lakes are Balnlis,Medialenk, Maigai andMeiiai.

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Chemical and biological tests of riverswater in Maeikiai district

Along the rivers andrivulets there are 12scattered burialmounds. Rimoliai,Vadagiai, Renavas,Dapiai, Daubariai aremostly visited bytourists.

Work Process

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Oxygen

Dissolved oxygencontent in waterindicates thecontamination rate (theless oxygen dissolves inwater, the more pollutedthe water is).

If the dissolved oxygencontent in natural wateris less than 3.0 mg / l it

can be used for drinkingand domestic usage.

07

6 ,36 ,3

9

Control (Tap water)Venta River Vieet River

K vist R iver Varduva R iver erkn R iver

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Ammonium

The concentrationlimit of ammonium is0,5 mg/l

0,2

00

0,20,2

0,2 Control (Tap watVenta RiverVieet RiverKvist RiverVarduva Rivererkn River

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Nitrite

Nitrite ions areparticularly dangerous asthey may cause cancer.

The concentration limitof these ions is 0,5 mg/lfor adults and 0,02 mg/lfor infants.

0 10

1 0

1 0

1 0

1 0 Co n t ro l ( Ta p waVen t a Ri v erVi e e t R i v erK v is t R i verVa rd u v a Ri vererk n Ri v er

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Phosphate Excess of phosphate in

natural waters, running watercan kill plants, fish and otherliving organisms ascontaminated water emits anunpleasant odor, and thewater becomes green andslimy.

In the past, one of the majorsources of phosphate weredetergents. Phosphate

pollution used to spread fromsewage and wastewater fromfarms, agricultural fields.

0,25

0,25

0,50,25

0,5 Control (Tap watVenta RiverVieet RiverK vist R iverVarduva Rivererkn River

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Nitrate

The excess of nitrates insurface waters intensively

provokes the growth ofalgae. When algae diethey pollute the water. Theexcess of nitrate indrinking water can causehealth problems. Theexcess is particularlydangerous to newborns.

The maximum nitrate indrinking water is 10 mg/l.

0

0,250,1

0,05 0,01 Control (Tap watVenta RiverVieet RiverKvist RiverVarduva Rivererkn River

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pH

pH is extremely important inassessing the quality of thewater. The water pH medium(acidic or alkaline) dependson the waters biological and

biochemical processes. pHhas the influence on the speedof water plants growth. Dueto pH, metal constructions(bridges, balks, etc.) can start

rusting. Drinking water should not

exceed 6.5 to 8.5 pH range.

6

7,5

66,5

6

7 Control (Tap watVenta RiverVieet RiverK vist RiverVard uva Rivererkn River

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Water conduction

Electrical gooddrinking water fromthe tap is theconductivity of 600micro Simens (S /cm).

When the waterconductivity varies

between 5-7 S / cm,the water is distilled.

0035

37

25

26 Control (Tap watVenta R iverVieet RiverK vist RiverVarduva Rivererkn River

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Free and total chlorine

It is used for waterdisinfection. To therivers chlorine fallswith municipalsewage. Rate of 0.08mg / l.

00 0 ,1

0 ,50 ,5

0 ,1Control (Tap waVenta RiverVieet RiverKvist RiverVarduva Rivererkn River

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Iron, Fe

Iron is found in allsurfaces andunderground waters.

The maximumallowableconcentration of ironin waters intended forhousehold and

farming needs is 0.3mg / l.

Copper, Cu

Copper is essential formany vital functions oforganisms. Plants take itout of the soil, man andanimals get it from food.

High doses of coppervertebrates causediarrhea, respiratorydisturbances, heart, liverfunction, anemia.

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00 0 ,1 0 ,1

0 ,51

Control (Tap watVenta RiverVieet RiverKvist RiverVarduva Rivererkn River

Total alkalinity

Alkalinity shows how muchthe tested water has alkalinesubstances, hydrogen reactswith strong acids, i.e., withhydrogen ions.

Alkalinity is an importantindicator of drinking waterfor effecting plants, wastewater, heating or coolingsystems.

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00

120

4040

80 Control (Tap watVenta R iverVieet RiverK vist RiverVarduva R ivererkn River

Total hardness

Hard water is not

suitable for cooking athome as it can causecardiovascular andurinary excretionsystem disorders.

The total water supplyfor drinking waterhardness must be lessthan 7 mg-eq / l, good -no more than 10 mg-eq

/l.

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0

50

0

25

15Control (Tap watVenta RiverVieet RiverK vist RiverVarduva Rivererkn River

Animals

There are 38 species ofdragonflies in Maeikiaidistrict. They usually fly overwater and forest lanes. Thelarvae are living in the waterand they are predatores.

Green Club-tailed Dragonfly,included in the Red data bookof Lithuania, lives in the clearoxygen filled water of the riverVarduva.

Broad-winged damselflies arefound in all rivers.

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Animals

Swan mussels are the mostwidely spread limpet speciesliving in the rivers.

These limpets eat organicresidues of plants and smallanimals. These bivalves aregood water filtrators (duringthe day they filter severaldozen liters of water). Animportant condition is that in

all seasons there would besufficient amount of oxygen inthe water.

Animals

TheBrown Troutissparsely found in theerkn and Vieetrivers.

This fish is rare inLithuania, therefore, itis banned to fish themduring spawning.

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Animals

The Spined Loach,Gudgeon andBleakaretypical fish of rivers andthey are rather rare.

Animals

The most beautiful bird inLithuania -European

Kingfisheris found on thebanks of all investigatedrivers.

These birds dig smallcaves on the banks of

streams where they breed.

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Animals

The beavers live inall of our surveyedrivers. Many beaverdams are in VieetRiver and less inVarduva River. Butin erkn River theamount of them isvery low because its

water is extremelycold.

Plants

Stiff White WaterCrowfootis one ofmore than 700 plantspecies growing inthe area.

It is a rare andprotected plantspecies. This plantgrows in the bedsof Varduva and

erkn rivers.

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Conclusions

We havent found iron ions in any investigated rivers.

Dissolved oxygen, ammonia content and pH of all therivers are in the normal range.

About 10 mg/l of nitrite are found in all the rivers,what is more than the norm.

The level of nitrate does not exceed the limit.

Three rare and protected animal species, such as Green

Club-tailed Dragonfly, Brown Trout,EuropeanKingfisher, are living in our investigated rivers.

Water tests conducted by Greta Rakauskait, ErnestasGarjonis, Vaida Norkut, Lukas Budreika and Vytautas

Raginis.

Photos by Algirdas Vilkas and other sources.

2011