[Strona główna]         [Chemia]        [Podróże]       [Kalcyt]           [Linki]

 

 

HYDROGEOTECHNIKA – technologie dla środowiska

 

 

 

Sekcja: Forum Młodych, poster: P008

SEASONAL VARIABILITY IN THE CHEMISTRY OF WATER FROM THE WARKOCZ RIVER 

K. Wołowiec, S. Dołęgowska

Institute of Chemistry, Faculty of Mathematical and Natural Sciences,

Pedagogical University, 5 Chęcińska Str., 25-020 Kielce

 

ABSTRACT

The water samples collected from the Warkocz River (central Holy Cross Mts) were analyzed during June 2003 – May 2004. The results showed a seasonal variability in the chemistry of water, especially in the concentrations of nitrogen compounds derived from fertilizers (agriculture) and sewerage (farms). 

 

INTRODUCTION

Rivers are important pathways for transport of pollutants [1]. In Poland only big rivers have been monitored systematically [2], although streams flowing through rural areas carry away many pollutants, primarily nitrogen and phosphorus, coming from the use of fertilizers [3]. The principal objective of our study was to compare the chemistry of river water samples collected monthly (except for October of 2003 and January of 2004) at two investigation sites, and to pinpoint the possible pollution sources.   

 

EXPERIMENTAL

During June 2003 – May 2004 a series of ten water analyses was done. Two investigation sites were selected: (1) in the upper course of the Warkocz River near the Górno village, and (2) at the confluence of the Warkocz and Lubrzanka Rivers (Fig. 1).

The samples were placed in polyethylene bottles and transported to the Geochemistry and the Environment Division laboratory in the Institute of Chemistry (Pedagogical University in Kielce). The waters were analyzed on the day of sampling. The pH and conductivity were measured with portable pH- and conductivity-meters (ELMETRON). The analyses of alkalinity and selected ions, i.e. ammonium, nitrate, nitrite, chloride, phosphate, sulfate, sulfide, zinc, were done with a spectrophotometer LF205 (SLANDI).

 

Fig. 1. Localization of investigation sites

 

RESULTS AND DISCUSSION

The results of chemical analyses are presented in Table 1. The water at both investigation sites is slightly alkaline with the pH in the range of 7.25 – 8.33, which is linked to the presence of Midlle and Upper Devonian limestones forming the bedrock of the study area. The higher pH values are noted at site 1 (except for September of 2003). The alkalinity of water also shows seasonal variability with the highest values during the summer and fall of 2003 and the lowest in February and March of 2004. This is due to the dilution effect brought about by spring thaws. There is a correlation between the pH and alkalinity of the samples (Fig. 2). The conductivity values are within 1st quality class for surface waters.

 

Table 1. The results of analyses of water samples from the Warkocz River

Parameter/unit

Site No.

Date of sampling

June ‘03

July ‘03

August ‘03

September ‘03

November ‘03

December ‘03

February ‘04

March ‘04

April ‘04

May ‘04

Ammonium

[mgNH4+/dm3]

1

0.1

0.2

0.3

0.4

0.2

0.4

0.5

0.4

0.3

0.3

2

0.2

0.3

0.5

0.3

0.2

0.3

2.8

0.2

0.1

0.2

Nitrite

[mgNO2-/dm3]

1

0.16

0.19

0.17

0.04

0.10

0.13

0.14

0.03

0.09

0.10

2

0.05

0.02

<0.02

<0.02

0.09

0.15

0.09

0.04

0.10

0.63

Nitrate

[NO3-/dm3]

1

4.1

11.7

4.7

3.6

6.8

3.6

4.9

4.6

3.0

4.2

2

6.3

4.7

7.7

7.6

7.2

5.6

5.1

6.1

11.6

8.0

Chloride

[mg Cl-/dm3]

1

16.5

21.0

11.7

<2.0

12.8

21.0

12.4

9.7

9.5

10.4

2

14.6

16.5

15.0

15.4

15.2

15.7

11.5

10.7

9.6

8.4

Phosphate

[mgPO43-/dm3]

1

<0.1

<0.1

<0.1

<0.1

<0.1

0.1

<0.1

<0.1

<0.1

0.1

2

<0.1

0.3

<0.1

<0.1

<0.1

<0.1

<0.1

<0.1

<0.1

<0.1

Sulfate

[mgSO42-/dm3]

1

28

36

32

26

45

48

33

51

39

45

2

26

30

40

47

35

39

33

39

30

28

Zinc

[mg Zn2+/dm3]

1

0.10

0.07

0.15

0.13

0.09

0.13

0.14

0.14

0.15

0.16

2

0.08

0.07

0.09

0.09

0.06

0.08

0.10

0.14

0.14

0.13

Alkalinity

[mgCaCO3/dm3]

1

135

184

167

194

156

114

38

52

123

158

2

95

110

86

105

108

86

42

52

97

123

pH

 

1

8.09

7.72

8.33

7.37

7.54

8.00

7.43

7.35

7.90

7.74

2

7.78

7.44

7.40

7.45

7.25

7.70

7.35

7.27

7.38

7.57

Conductivity

[μS cm-1]

1

329

426

371

415

425

318

163

239

355

383

2

308

316

308

334

256

342

248

278

341

427

 NOTE: sulfide – <0.05 mg/dm3 in all samples

 

Of the different nitrogen species analyzed, ammonium is of special interest because it may be an indicator of domestic sewage pollution. The highest level of NH4+ (2.8 mg/dm3) was noted in February of 2004, which could be explained by the spring thaw leading to overfilling of cesspools and washing away of all organic wastes accumulated in snow. The remaining analyses show the concentrations of NH4+ below 0.5 mg/dm3, i.e. the allowable limit for 1st surface water quality class according to the Minister of the Environment enactment [2]. The higher NO2- contents are recorded at site 1. Only 4 measurements are below 0.03 mg/dm3 (1st class) and the remaining ones are above this threshold (2nd and 3rd class). One sample reveals 0.63 mg/dm3 NO2- (4th class). NO3- exhibits elevated concentrations at site 2 (4.7 to 11.6 mg/dm3, with a mean value of 6.99 mg/dm3) compared to site 1 (3.0 to 11.7 mg/dm3, mean 5.12 mg/dm3). The nitrate concentrations are relatively low in the Warkocz River and correspond to 2nd surface water quality class. The highest concentration of NO3- recorded in April of 2004 at site 2 is probably linked to the use of fertilizers.

The concentrations of Cl-, SO42- and Zn2+ in the Warkocz River are relatively low and are related to 1st surface water quality class (100 mg/dm3 for Cl- and SO42-; 0.3 mg/dm3 for Zn2+). The concentrations of PO43- in two samples correspond to 2nd surface water quality class. The water is oxygenated with sulfide concentrations below the detectable limit for a given method.

 

Fig. 2. Alkalinity (mg CaCO3/L) versus pH in the samples analyzed

 

CONCLUSIONS

The analyses of the Warkocz River water allow us to conclude:

1.            The chemistry of the water has revealed seasonal variability.

2.            The major factors that govern the chemistry of the analyzed water are natural (spring thaws) and anthropogenic (fertilizers, domestic sewage). This regularity is evident at site 1, but not at site 2 (river mouth) located far from the built-up area; the water of the river stretch between these sites is cleaned by natural processes.

3.            The chemical results indicate that the seasonal impact on the water chemistry should be taken into account when planning a multi-year hydrologic monitoring.

  

ACKNOWLEDGMENTS

The authors would like to thank Prof. Zdzisław Migaszewski of the Pedagogical University in Kielce for reviewing this article and valuable remarks.

 

REFERENCES

[1] Alloway B.J., Ayres D.C., Chemiczne podstawy zanieczyszczenia środowiska, PWN, 1999, Warszawa.

[2] Rozporządzenie Ministra Środowiska z dnia 11.02.2004 r. w sprawie klasyfikacji dla prezentowania stanu wód powierzchniowych i podziemnych, sposobu prowadzenia monitoringu oraz sposobu interpretacji wyników i prezentacji stanu tych wód, Dz.U. 2004 nr 32 poz. 284.

[3] Allan David J., Ekologia wód płynących, PWN, 1998, Warszawa.

 

rhodium@autograf.pl

 

powrót