Threats to a small river and its urban catchment: Hydrological and hydrochemical assessment of Jaroszówka River in Białystok, Poland

Vol. 8 No 1, 77-87 2008

Threats to a small river and its urban catchment: Hydrological and hydrochemical assessment of Jaroszówka River in Biaáystok, Poland

ElĪbieta Jekatierynczuk-Rudczyk Department of Hydrobiology, Institute of Biology, University of Biaáystok, ul. ĝwierkowa 20B, 15-950 Biaáystok, Poland e-mail: [email protected]

Abstract Hydrological and hydrochemical analyses in the Jaroszówka river basin were carried out in hydrological year 2003. The quality of the Jaroszówka water is characterized by the lowest level of transformation of physical and chemical composition among the Biaáystok rivers. Specific pollution load, which was discharged from the catchment to the Jaroszówka riverbed was much smaller than the load discharged to the main Biaáystok waterway (Biaáa), but was similar to the load of the small urban rivers (BaĪantarka and Dolistówa). A lower degree of the Jaroszówka spring water transformation demonstrates a significant role for pollution that flows directly to the riverbed. Key words: water quality, urban river, urban springs, specific pollution load.

1. Introduction Degradation of the environment is one of the most important problems of the modern world. Deterioration of water quality, which leads to decreased usability, has become a problem, especially for industrialized and urbanized areas (Cheámicki 1997). Biaáystok is the largest city of northeastern Poland (population 280 000), and almost the entire city is located in the basin of the Biaáa River - the left tributary of the SupraĞl River. The northern section of the city is drained directly by the SupraĞl River and its two small tributaries (the Jaroszówka is one of them); whereas the southern section is drained by the Horodnianka, a tributary of the Narew (Podziaá hydrograficzny Polski 1983). The flowing waters of Biaáystok are exposed to various kinds of pollution. The primary sourc-

es of pollution are municipal and industrial sewage discharged into the water from point, linear or diffuse sources. Municipal pollution is above all fuelled by domestic sewage. It is a mixture of household waste, physiological excretions of humans and domestic animals, and other substances. Industrial pollution in the form of industrial sewage is channelled into rivers, streams, lakes, or groundwater. The sewage quantity and composition depends on the type of industry present in the region. In the Biaáystok region, the main sources of industrial sewage and pollution are the food processing industry (this type of sewage is rich in organic compounds, for example, lactic acid), textile industries, whose sewage contains dyes and phenols in addition to organic compounds, and power plants that discharge heat into surface waters (Raport 2004). In urban areas, point sources of pollution include sewage that is

78

E. Jekatierynczuk-Rudczyk

discharged in an organized manner; runoff from atmospheric deposition from unsewered areas is counted as a diffuse source; while the linear sources are associated primarily with transportation pollution and effluent that percolates to the groundwater from gas pipelines, and sanitary and sedimentation sewers (Cheámicki 2002). All types of wastewater have a high impact on water quality draining the urban areas. The existence of an extensive network of surface waters in Biaáystok and instructions from General Water Directive (Pusáowska-Tyszewska et al. 2005) contributed to the preliminary assessment of water quality of Biaáystok’s smallest river, Jaroszówka. Particular attention was paid to: - assessment of the current quality of Jaroszówka water, - determination of changes in water quality compared to other rivers flowing through Biaáystok (urban rivers) and its vicinity (suburban and forest rivers), - analysis of changes in Jaroszówka water quality during the past twelve years, - impact of groundwater on the quality of surface water in the Jaroszówka watershed area. Analysis of water quality in river and springs water on background of catchment conditions and calculation of index of catchment loads refers to ecohydrology concept (Zalewski 2000). Ecohydrology considers the functional interrelations between hydrology and aquatic ecosystems and their biota at the catchment (watershed) scale. It considers the use of ecosystem processes as tools to meet freshwater resource management goals, such as enhancing natural processes of nutrient retention to avoid harmful algal blooms. In effect, it proposes a ‘dual regulation’ of the system by simultaneously using ecological and hydrological processes to enhance the overall integrity of aquatic ecosystems in the face of human-mediated alterations.

2. Study area The surveyed area included the Jaroszówka catchment (Fig. Fig. 1a 1a) situated in Biaáystok and its suburban zone. According to the division of physical geography, the surveyed area constitutes the Póánocnopodlaska Lowland, Biaáostocka Height meso-region. It is situated between the Biebrza Valley on the north, Sokólskie Hills on the northeast, and Upper Narew Valley on south. To the east, the Biaáostocka Height borders the Poniemnie (Kondracki 1998). Numerous upheavals, which locally exceed 206 m above sea level, add variety to the landscape. Large drops in terrain give the impression of a young glacial landscape (Musiaá 1992).

Hydrologically the Jaroszówka catchment it included in the Vistula river-basin. Other rivers fowing through Biaáystok: Biaáa, Dolistówka and BaĪantarka (Fig. 1a). Jaroszówka is a direct left tributary of the regulated river SupraĞl (it flows into the irrigation canal that carries water to the SupraĞl river). According to Horton, Jaroszówka is classified as first-order. Its length equals approx. 3.8 km, and the area of the drainage basin is 3.42 km2. Fish ponds located in the central part of the catchment occupy an area of 0.25 km2. The average river flow rate between 1982 and 1983 equalled 13 dm3 s-1 and the specific watershed runoff equalled 3.5 dm3 s-1 km-2 (àoszewski 1983). Surveys conducted in the hydrological year 2003 (Jekatierynczuk-Rudczyk 2005) show no significant changes. The average flow rate in the central reaches of the river equalled 14 dm3 s-1. A very negative hydrological phenomenon occurs in the river´s closing cross–section (below the fish ponds), a periodic desiccation of the riverbed, which is caused by the retention of water in the ponds. The source of the river is located 147.5 m above sea level and its junction with the SupraĞl river 117.0 m above sea level. The drops of terrain within the river catchment, which exceed 30 m, are responsible for the occurrence of numerous natural underground water outlets. The spring density index equals 1.5. The river sources on average deliver 10 dm3 s-1 of water to the river (Jekatierynczuk-Rudczyk, ĩuk 2006). The forest cover index in the Jaroszówka catchment equalls 14.2%, and this low index is due to the presence of housing developments (single-family detached home developments of Wygoda and Jaroszówka).

3. Methods Hydrological and hydrochemical analyses in the Jaroszówka river basin were carried out in hydrological year 2003. The surveys along the river and the spring area were conducted every two months (6 times a year), and in section no. 2, nine times a year (Fig. 1b). Hydrological and hydrochemical surveys were carried out for 5 hydrometric sections (Fig. 1b). The distances were measured from the source to the outlet. 1 – upper section of the river, 0.5 km of the river course – below Raginisa street, 2 – upper section of the river, 1.0 km of the river course – at Skrzatów street, 3 - middle section of the river, 1.5 of the river course, 4 - middle reaches of the river, 2.5 km of the river course - at the ĝwiĊta Woda trail, 5 – end section of the river, below the fish ponds, 3.0 km of the river course. The field tests included: river flow and spring area discharge (hydrometric current meter or

Threats to a small river and its urban catchment

79

Fig. 1. Rivers in Biaáystok region (a) and Jaroszówka catchment (b).

Poncelet overflow), electrical conductivity, temperature, pH, oxygen saturation, concentration of dissolved oxygen (Hydrolab Minisonda 4a), and oxidation-reduction potential (pH-meter with a SenTix ORF electrode). The sampling of water for chemical analyses were performed in the river main current. Laboratory analyses were conducted according to methods described by Hermanowicz et al. (1976). The author analyzed: water color (field spectrophotometer, Slandi LF 205), hydrogen carbonate con-

centration, total hardness, calcium concentration (titrimetric method), magnesium concentration (determined from the difference between the total hardness and calcium concentration), and sodium and potassium concentrations (flame photometry, Carl Zeiss Jena device FLAPHO 4). The remaining chemical components of the surveyed water were determined by the Riedel - de Häen company, using a calorimetric method and spectrophotometer Beckman DU-650, with procedures and reagents in compliance with ISO standards. The author deter-

80

E. Jekatierynczuk-Rudczyk

Table I. Physico-chemical parameters (mean values) of rivers water in the Bialystok city. River

Biaáa

Dolistówka

BaĪantarka

C

10.4

10.4

11.9

7.2

pH

pH Electrolytic —S cm 1 conductivity Dissolved oxygen mg dm 3

7.5

7.6

7.4

7.6

958

996

1035

686

8.6

9.2

7.3

11.0

Oxygen saturation % 330 nm Absorbance

79 0.109

83 0.112

67 0.088

94 0.026

mg dm-3

110

120

117

115

-3

14.8

20.7

16.3

13.9

mg dm-3

54.5

53.8

68.4

16.2

-3

7.07

8.8

12.9

2.9

mg dm-3

341

323

363

303

mg dm

-3

53.9

55.6

50.1

48.3

mg dm

-3

47.4

43.5

45.9

32.3

mg dm

-3

0.610

0.325

0.322

0.164

mg dm

-3

3.23

4.91

5.18

3.45

source Parameter

Unit

Temperature

o

Ca 2+ Mg Na K

2+

mg dm

+

+

mg dm

HCO3 SO4

-

2-

-

Cl

2+3+

Fe

N – NO3

-

N – NH4

+

0.79

0.57

0.40

0.18

mg dm

-3

0.19

0.20

0.14

0.10

Total phosphorus mg dm

-3

0.88

0.74

0.73

0.28

P-

PO42-

mg dm

-3

Jaroszówka Jekatierynczyk– Samojlik 1997 Samojlik 1997 Samojlik 1997 Rudczyk 2005

mined the content of: iron, phosphorus as orthophosContent analysis of bivalent iron, sulphides, phate after percolation through a “GF/C” filter, total cadmium, copper, zinc, and chromium was carried phosphorus after acidification and mineralization out four times during the hydrological year in section no. 2 of the Jaroszówka river. The above propwith UV radiation, nitrate nitrogen and ammonia nitrogen contents, sulphate, chloride, and silicon erties were determined by the Riedel - de Häen company using a calorimetric method and a speccontent, and absorbance at the wavelengths 260 and 330 nm. The dissolved organic carbon (DOC) content was determined using Table II. Microelementes of water in the Jaroszówka River in 2003 year a Shimadzu organic carbon analyzer (section no. 2). (TOC) 5050A according to the proceRange Coefficient of Standard Parameter Unit maen variation dure proposed by ZieliĔski and deviation value [%] Górniak (1999). Total nitrogen content was determined using a Tecator 30 - 61 -3 13 30 Zinc Pg dm 2300 Kiedlahal analyzer. To determine 43 Specific UV Absorbance (SUVA), 1 – 39 17 99 Chromium Pg dm -3 spectrophotometrical absorbance at 18 260 nm was measured and SUVA 8 - 15 3 25 Kadmium Pg dm -3 parameter was computed using for12 mula (Chin et al. 1994, modified): 13 – 38 18 69 Copper Pg dm -3 26 Abs 260 u 1000 SUVA = 42 – 64 9 17 Sulphides Pg dm -3 DOC 52 SUVA = [Abs260 g-1 dm-3]

Iron 2+

Pg dm -3

18 – 127 66

52

79

Threats to a small river and its urban catchment

trophotometer Beckman DU-650, with procedures and reagents in compliance with ISO standards. Additionally, hydrological and hydrochemical surveys were conducted for four springs (Fig. 1b). These are both descending and ascending layered outlets (spring no. 4) (Fig. 1b). The most common morphological form of outlet is a circular, oval, or semi-circular recess, although trough and V-shaped outlets are also present (àoszewski 1995). Hydrobiologically, the springs were classified as helocrene (no. 4), rheocrene (no. 2 and 3), and limnocrene (no. 1) (Gòrniak, JekatierynczukRudczyk 1997, Jekatierynczuk-Rudczyk 1999, Jekatierynczuk - Rudczyk, ĩuk 2006). In order to assess the impact of the watershed on river water quality, the watershed area and an index (specific pollution load) describing the component concentration in the water was calculated. M=

component concentration flow rate watershed area

[mg km-2 s-1] =

[mg dm-3] [dm3 s-1] [km2]

Statistical calculations were conducted using the software program Statgraphics for Windows 5.0.

4. Results The electrolytical conductivity of water in Jaroszòwka river did not exceed 700 —S cm-1. The water in the river showed very good of saturation (94%) and small concentration of macroand microelements (Table I, II). Most of the analyzed properties of the Jaroszówka water had lower average values and concentrations than found in the other Biaáystok rivers (Table I). Statistically significant differences were related to electrical conductivity of water, its coloration (expressed as light absorption at a wavelength of 330 nm), and concentrations of sodium, potassium, iron and total phosphorus (multiple comparison test). High concentrations of sodium, potassium, and chloride ions were observed in rivers flowing through densely built-up urban areas. The concentrations of sodium and potassium in the Jaroszówka water were almost four times lower than in other rivers of the town. The average concentrations of sulphates and orthophosphates were comparable in all Biaáystok rivers (Table I). Nitrogen compound contents in surface waters of Biaáystok were less diversified. The concentration of nitrate nitrogen was higher than that of ammonia nitrogen (Table I). The highest average value of total phosphorus was found in the Biaáa river; in Jaroszówka, this parameter was on average three times lower (Table I).

81

The river water showed low microelements concentration (Table II). The average for chromium was 18 Pg dm-3. The highest mean values were observed for iron – 66 Pg dm-3. The liability of microelements in water was also small (Table II). The coefficient of variation did not exceed 100 %. The chemical composition of the water of the Jaroszówka river varied at different testing locations. The lowest mean values of water temperature, concentration of dissolved oxygen, water color, magnesium, chloride, and sodium content (Fig. 2a-f) were observed in the first testing station near the river spring of Jaroszówka river (Fig. 1b). Here, average DOC content and analyzed forms of phosphorus were highest (Fig. 2g-l). In lower river the nitrate and organic nitrogen concentrations were highest. The highest concentration of ammonia nitrogen were observed in lower course (Fig. 2j-l).

5. Discussion The physicochemical and biological properties of the water determine its usability for different purposes. Some water properties are used to assess water quality and degradation level (Cheámicki 1997, 2002). The results of the hydrochemical analyses of the Biaáystok rivers are similar to those published by institutions that survey the condition of the natural environment (Stan czystoĞci 1998). Most of the analyzed hydrochemical parameters classify the waters of Jaroszówka and other rivers of the town as a class I water. The concentrations of total phosphorus, nitrate nitrogen, and chlorides are characteristic for class II water. The primary properties that lower the quality class of the town water are water electrical conductivity and calcium concentration. These values classify the surveyed waters as IIIrd class. Total phosphorus content in the Jaroszówka river, which corresponds to the class II water, is also noteworthy. Such content was unusual for the analyzed town waters. The classification of Biaáystok surface waters to the III water quality class was confirmed by the survey conducted by WIOĝ in 2003 (Raport 2004). Almost 50% of the flowing waters surveyed in Podlaski province belonged to the III class of water quality. None of the surveyed sections of the rivers had water of highest quality. In Podlaski province, municipal sewage is the primary source of pollution; therefore, anthropogenic changes to water are greatest in large urban areas (Raport 2004). The concentrations of microelements in urban surface waters are an important factor in water quality classification (Table II). Their contents in the Jaroszówka waters were not significant in comparison to the permissible values. The average

82

E. Jekatierynczuk-Rudczyk

50

a) Conductivity -3

[mg dm ]

1.5 1 0.5

30 20 10 0

0 250

0.5 1 1.5 2 2.5 3 b) Oxygen saturation km of river course

0.5

3.5

50

800

-3

4 2

4

[mg dm ]

40

-3

-3

[mg dm ]

3.5

30 20

1

1.5

2

2.5

km of river course

3

2.5

3

3.5

0.5 1 1.5 2 2.5 3 j) Organic km ofnitrogen river course

3.5

0.5

1

0.5

0.5

3 2 1

3.5

1.5

2

2.5

3

3.5

1

1.5

2

2.5

3

3.5

1

1.5

2

2.5

3

3.5

10

15

km rivernitrogen course k) of Nitrate

-3

[mg dm ]

-3

2

0 0.5

e) Potassium

[mg dm ]

1.5

km of river phosphorus course (SRP) i) Soluble reactive

0 0.5 1 1.5 2 2.5 3 d) Sodium km of river course

0

10 5

5

0

0 0.5

1

1.5

2 2.5 3 f) Chlorides km of river course

3.5

800

l) Ammonium nitrogen km of river course

600

-3

[—g dm ]

80 -3

1

0.5

200

10

[mg dm ]

3.5

400

0

100

3

600

[—g dm ]

-3

[mg dm ]

3.5

6

20

2.5

0 0.5 1 1.5 2 2.5 3 c) Silicon km of river course

8

50

2

0.5

0

60

1.5

-3

100

10

1

h) Total phosphorus km of river course

1

150

[mg dm ]

[%]

200

12

g) Dissolved organic carbon (DOC)

40

3

-1

[10 —S cm ]

2

60 40 20

400 200 0

0 0.5

1

1.5 2 2.5 3 km of river course

3.5

km of river course

Fig. 2. Physico-chemical parameters along Jaroszówka river course in 2003 hydrological year (mean value, maximum and minimum).

Threats to a small river and its urban catchment

Table III. Water quality in the Jaroszówka River (section no. 2) in 1992 year (Grochowska 1993) and 2003 year.

Parameter Temperature pH Electrolytic conductivity Dissolved oxygen Oxygen saturation Ca2+ Mg2+ Na + K+ HCO3Cl N - NO3N - NH4 + P - PO42-

Hydrological year Sample dimension Unit 0 C pH

1992

2003

n=9

n=9

8.7 7.67

9.0 7.67

—S cm-1

656

789

mg dm-3

11.3

11.2

%

94

96

127 21.6 10.8 1.17 300 46.0 3940 1016 114

134 10.5 13.0 0.63 332 41.1 5142 202 34

-3

mg dm mg dm-3 mg dm-3 mg dm-3 mg dm-3 mg dm-3 —g dm-3 —g dm-3 —g dm-3

contents of zinc and chromium classified the tested water as the Ist class, while the content of copper as IInd class, and cadmium as IVth class. In comparison to values typical for surface water, the concentrations of the above elements in the Jaroszówka water were significantly higher (Cheámicki 1997). At the same time, concentrations of zinc, copper, and chromium in Jaroszówka waters were considerably lower than in the main Polish rivers (Dojlido 1995). Significantly lower concentrations of microelements in the Jaroszówka water in comparison to that of other rivers confirm the high quality of Biaáystok flowing waters, but simultaneously demonstrate that these waters are in the initial phase of degradation. Despite the fact that the water in the Jaroszówka was of higher quality than other flowing waters in Biaáystok, the water quality of the urban river was highly transformed in the Biaáystok region (Jekatierynczuk-Rudczyk, ZieliĔski 2004). Analyses of water quality in Jaroszówka demonstrated that the most substantial changes in the chemical composition occurred in section no. 2 where the river leaves the densely built urban area. In this section, electrical conductivity of the water exceeded 800 —S cm-1 (Fig. 2a-l), and analyses yielded the highest average water coloration, chlorides, silicone, and ammonia nitrogen and nitrate nitrogen contents. This is a common phenomenon; the water quality of rivers that flow through urban areas is often altered to the highest degree (Kayabak et al. 1999). The fish ponds located below the third hydrometric cross-section were found to have a significant impact on the

83

reduction of electrical conductivity and concentrations of dissolved oxygen and most macroelements. However, the concentrations of DOC, iron, organic nitrogen and surveyed forms of phosphorus (Fig. 2a-l) increased. In the downstream direction, oxygen saturation decreased, and could have been consumed during water selfpurification. In the fish ponds, oxygen was consumed by autotrophic organisms, especially in the summer when water blooms were frequently observed (Dojlido 1995, Gòrniak et al. 1999, Olguin et al. 2004). The comparison of water quality in hydrometric cross-section no. 2 in the Jaroszówka sampled at different times (Table III) demonstrated that the analyzed physical and chemical properties have been stable over the past decade. Statistically significant differences pertained to water electrical conductivity, and concentrations of mineral forms of nitrogen and phosphorus (multiple comparison test). Water electrical conductivity and contents of nitrate nitrogen compounds increased, while the contents of ammonium nitrate and orthophosphates substantially decreased (Table III). Increased concentrations of nitrates and decreased content of ammonium nitrate demonstrates that the sources of pollution have moved away from the riverbed in the later period of the study. This fact corresponds to completion of the sewage system in the housing development in Jaroszówka at the end of 1990s. The quality of flowing waters in Poland have significantly improved in the past decade (Raport... 2003). However, in Biaáystok such an improvement has not been reported, and this is related to the poor industrialization of the region, which has long been considered the ‘green lungs of Poland’. Many factors associated with anthropogenic activities have a negative impact on the water quality of the Jaroszówka river. The primary factors include: - industrial and residential developments (singlefamily home development - Jaroszówka, Construction Materials Factory – Sylikaty and its excavations, small construction and food companies and other small businesses), especially in the areas where the shallow ground waters are drained by spring areas; this phenomenon was observed in the mid-1990s, when a spring recess was built over, - existence of old dumps, local landfills, leaking sewage systems in the watershed area, especially in the 1990s, - pollution of the ground surface related to, for example, usage of agents to treat icy roads, usage of fertilizers on plots located in the watershed areas. The comparison of concentrations of physical and chemical substances dissolved in water enables a general assessment of water quality. However, determination of the catchment impact

84

E. Jekatierynczuk-Rudczyk Table IV. Surface water specific pollution load in the Bialystok City - hydrological observation: flow rate, watershed area, specific runoff. River

Flow rate

Dolistówka

BaĪantarka

Jaroszówka

àoszewski 1983 àoszewski 1983 àoszewski 1983 own data 2003

source Parameter

Biaáa

unit dm 3 s-1 2

1110

80

29

14

108.2

16.4

11.3

3.4

Watershed area

km

Specific runoff

dm 3 s-1 km-2

10.2

4.3

2.5

4.1

Calcium

mg s-1 km-2

1132

586

300

471

Magnesium

mg s-1 km-2

155

101

42

57

-1

-2

Sodium

mg s km

555

262

175

66

Potassium

mg s-1 km-2

56

43

33

12

-1

-2

3497

1576

932

1240

-1

-2

555

271

129

198

-1

-2

488

212

118

132

-1

-2

7

2

1

1

-1

-2

33

24

13

14

8

3

1

1

2

1

0,4

0,4

9

4

2

1

Bicarbonates Sulphates Chlorides Total iron Nitrate nitrogen

mg s km mg s km mg s km mg s km mg s km

Ammonium mg s-1 km-2 nitrogen Soluble reactive mg s-1 km-2 phosphorus Total phosphorus mg s-1 km-2

on these concentrations is impossible. The quality of water in the riverbed depends on processes that occur not only in the riverbed but also in the river basin. The quality of the water that is drained from similarly used areas depends on the size of the catchment, flow rate in the riverbed, and morphometric parameters, especially the length of a river, which determine the water’s ability to self-purify. Calculation of a specific pollution load that is discharged into riverbeds from catchment allowed interpretation of the transformation level of the surface catchment of the Biaáystok rivers (Table IV). The catchment load in the Jaroszówka was much lower in comparison to the main waterway in Biaáystok (Table IV). Catchment of the small rivers (BaĪantarka and Jaroszówka) demonstrated similar capabilities of catchment related pollution associated with nutrients (Table IV), which demonstrates that the size of a catchment has an impact on the quality of the flowing waters. Similar concentrations of N-NO3 in Biaáa and Jaroszówka (Table I) and different indexes of catchment loads clearly indicate the transformation of nitrogen forms as a result of self-purification. The river water in the area of Biaáystok was transformed to a greater degree than the water in the spring areas. The average water temperature in the river was lower. This was a result of much

lower air temperature in the winter (December – February) of 2003 (mean temperature: -6.2) than in the same period in 1992 (mean temperature –1.3). In 2003, the river had periodic ice cover and landfast ice. As a consequence, the concentration of dissolved oxygen and the degree of oxygen saturation were higher (Table V). Water of the spring area and the river had similar average values of water coloration, pH, oxidation-reduction potential, and concentrations of calcium, magnesium, sodium, silicon, and nitrogen compounds. However, numerous parameters that are related to the pollution of the aquatic environment were significantly different in the river and spring waters (multiple comparison test) located in the catchment area. The river water had higher values of conductivity and content of sulphides, chlorides, iron and tested phosphorus forms. Average concentrations of DOC in the river were two times higher than in the spring areas. In the Jaroszówka, organic matter aromaticity, which is described by the SUVA parameter, was twice as high as in the spring area waters (Table V). These average concentrations in two different aquatic environments demonstrate that the role of surface pollution is quite significant. Surface pollution is released into water from both point sources and in the form of surface and hypodermic runoff

85

Threats to a small river and its urban catchment Table V. Water quality in the Jaroszówka catchment in 2003 year (river water - all spring water). habitat Jaroszòwka River Sample n=17 dimension coeff.of mean range variation mean Parameter Unit [%] 0 C 7.2 4.7 – 9.0 62 9.2 Temperature pH 7.6 7.1 – 7.7 5 7.4 pH mV 192 181-199 19 184 Redox potential Electrolytic -1 —S cm 686 506 - 803 16 597 conductivity -3 11.0 9.8 – 12.3 16 10.0 mg dm Dissolved oxygen % 94 76 - 107 17 88 Oxygen saturation Dissolved Organic mg dm -3 4.8 2.5 – 12.7 144 2.6 Carbon (DOC) 13.6 3.1 – 14.8 49 11.3 mgPt dm -3 Water colour abs 1 cm Specific UV 51 17 95 169 22 1gC -1 Absorbance (SUVA) mg dm -3 115 75 - 133 18 104 Ca2+ mg dm -3 13.9 11.5 – 17.3 35 11.3 Mg2+ mg dm -3 16.2 12.2 – 20.3 40 14.0 Na+ + K mg dm -3 2.9 0.4 – 4.3 134 4.3 HCO3mg dm -3 303 256 - 330 11 304 mg dm -3 48.3 47.0 – 51.3 10 36.3 SO42mg dm -3 32.3 22.7 – 45.1 44 24.7 Cl mg dm -3 3.3 1.6 – 4.6 46 3.5 Si 164 75 - 305 180 58 —g dm-3 Fe 823 438 - 1783 52 771 —g dm-3 Organic nitrogen —g dm-3 3447 1329-5055 51 3306 N-NO3—g dm-3 176 115 - 376 74 187 N-NH4+ —g dm-3 280 125 - 819 201 244 Total phosphorus P-PO42—g dm-3 102 39 - 325 209 68

after intense atmospheric precipitation or snow cover melting (Kayabak et al. 1999). The character of the Jaroszówka as a drainage river (Jekatierynczuk-Rudczyk 2005) creates conditions for dissemination of pollution carried by the groundwaters. However, the quality of these waters, characterized on the basis of the spring area, rather contributes to dilution of pollution rather than its accumulation (Table V). The water in all surveyed spring areas was found to be of the two ion, bicarbonate – calcium hydrochemical type. The above is a basic water-type characteristic for outlets. Most of the spring area of the Puszcza KnyszyĔska is characterized by the twoion water type (Jekatierynczuk-Rudczyk 1999). At the beginning of the 1990s, some Biaáystok spring areas were characterized by the multi-ion hydrochemical water type (Gòrniak, Jekatierynczuk-Rudczyk 1997, JekatierynczukRudczyk 1999). Currently the the quality of the spring waters has improved. There are no noticeable transformations of water flowing from outlets located in the urban areas, which could be a result of improving tightness of the sewage system and decreased anthropogenic impact due to

investigative sections and Springs n= 21

0.3 – 5.4 7.2 –7.6 179 - 201

coeff. of variation [%] 39 4 23

412 - 751

29

8.9-12.3 79 -104

19 20

1.2 – 4.7

130

4.7-16.3

52

18-26

46

88-128 7.6- 13.3 9.8 - 16.9 1.9 – 7.4 251-344 13.2-47.2 14.2-32.4 2.8 – 3.8 52 - 57 671-1016 671-5354 118 - 348 155 - 320 62 - 84

20 41 66 123 15 40 40 68 47 58 63 69 100 89

range

the current economic situation in the Biaáystok region. The chemical composition of water in the Biaáystok spring areas is little transformed in comparison to that of large Polish cities (Macioszczyk et al. 1991). Despite the relatively high quality of the groundwater in the northern section of Biaáystok, there are symptoms of changing water chemical composition, which could be a result of industrial activities in the urban area (Table V). These changes are primarily associated with water electrical conductivity, which in some Jaroszówka catchment outlets exceeded 700 —S cm-1. There is an alarming situation regardingwater quality in the spring area no. 3 (Fig. 1b). The concentrations of sodium and potassium ions in the waters of this spring are highest among spring areas of Biaáystok. This outlet is located within the city limits, and is closest to the industrial areas. Its recess has been transformed during the construction of the housing development - the rheocrene has been transformed into an artificial limnocrene. The changes in the water chemical composition are greatest among all springs of the Jaroszówka catchment (Jekatierynczuk - Rudczyk, ĩuk 2006).

86

E. Jekatierynczuk-Rudczyk

The temporal stability of the water chemical composition is noteworthy. The analysis of the water property variability index in the Jaroszówka river and its watershed spring areas showed significant similarities in these aquatic environments. In the areas characterized by a low level of environmental transformation, the chemical composition of the groundwater outlets is less variable than in the developed areas (Jekatierynczuk-Rudczyk 1999) and much less variable than in the surface waters (Jekatierynczuk-Rudczyk, ZieliĔski 2004). Similarities in the hydrochemical property variability in spring areas and in the river were a result of the substantial fraction of groundwater from natural outlets in the surface waters (70%). The slightly less variable parameters of the groundwater from the natural outlets located in Biaáystok included: water temperature, dissolved compounds of organic carbon, quality of the organic matter, and concentrations of potassium, iron, and tested compounds of phosphorus (Table V). Anthropogenic transformation of the surface water quality is common in Biaáystok, but in many cases, it is insignificant and difficult to detect. If the anthropogenic changes in water chemical composition are so small that the concentrations of individual elements do not exceed the standard values, then we are observing the initial phases of anthropogenic impact (Macioszczyk 1991; Nagoye, Machiwa 2004). Human pressure becomes noticeable only when the water is clearly polluted. In such a situation, it is usually too late to undertake effective actions that would reduce the pollution. These counteractive actions would certainly be more effective if they were launched earlier; therefore, detection of the first symptoms of anthropogenic changes in water quality are of utmost importance. The above statement is an instigation for constant monitoring of the water bodies, especially in urban areas, which are not covered by monitoring conducted by the province’s authorities.

Conclusions The quality of the Jaroszówka water is characterized by the lowest level of transformation of physical and chemical composition among the Biaáystok rivers; Among the Jaroszówka water physicochemical parameters most transformed by anthropogenic factors are water temperature, electrical conductivity, concentrations of sodium and chloride ions, and mineral forms of nitrogen. The highest level of water quality changes was found in the cross-section located where the river leaves the densely built urban area. Urban arrangement allows for the quick runoff of precipitation and thaw waters to the riverbed,

increasing the rate of flow; these waters carry a considerable pollution load from the surface. Specific pollution load, which was discharged from the catchment to the Jaroszówka riverbed was much smaller than the load discharged to the main Biaáystok waterway (Biaáa), but was similar to the load of the small urban rivers (BaĪantarka and Jaroszówka). A lower degree of the Jaroszówka spring water transformation demonstrates a significant role for pollution that flows directly to the riverbed.

Acnowledgements Hydrochemical surveys of the Jaroszówka in section 2 were part of KBN research project no. 3 PFO 017 23 „Role of the hyporeic zone in small lowland rivers”

6. References Cheámicki, W. 1997. Degradacja i ochrona wòd (czĊĞü pierwsza) JakoĞü. [Degradation and water protection (part one) Qality] Wydawnictwo Uniwersytetu JagieloĔskiego, Kraków. Cheámicki, W. 2002. Water. Resources, degradation, protecion. [Woda. Zasoby, degradacja, ochrona] wyd. Nauk. PWN, Warszawa. Chin Y., Aiken G., O’Loughlin E. 1994. Molecular weight, polydispersity, and spectroscopic properties of aquatic humic substances. Env. Sci. Technol. 28, 1853-1858. Dojlido, J.R. 1995. Chemia wód powierzchniowych. [Surface water chemistry] wyd. Ekonomia i ĝrodowisko, Biaáystok. Górniak, A., Jekatierynczuk-Rudczyk, E. 1997. Anthropogenic changes in spring water quality in the area of Biaáystok (north-eastern Poland)., Acta Hydrobiol. 39, 19-28. Górniak, A., Jekatierynczuk-Rudczyk, E., ZieliĔski, P. 1999. Transformacje chemizmu wód rzeki Narew w zbiorniku zaporowym Siemianówka. [Transformation of river Narew water chemistry in the Siemianwka reservoir.] In: Przedwojski B. [Ed.] Eksploatacja i oddziaáywanie duĪych zbiorników nizinnych na przykáadzie zbiornika wodnego Jeziorsko wyd. AR PoznaĔ, Uniejów, pp. 395-407. Grochowska, B. 1993. Dynamika skáadu chemicznego wód rzek Puszczy KnyszyĔskiej [Rivers chemistry in the KnyszyĔska Forest.] Msc Thesis, Biaáystok Branch - University of Warsaw. Div Animal Ecology Hermanowicz, W., DoĪaĔska, W., Dojlido, J., Koziorowski, B. 1976. Fizyczno-chemiczne badania wody i Ğcieków [Physico – chemical investigation of water and sewage.] Arkady, Warszawa.

Threats to a small river and its urban catchment

Jekatierynczuk–Rudczyk, E. 1999. Effects of drainage basin managment on the chemical composition of waters in lowlands springs. Acta Hydrobiol. 41, 97–105. Jekatierynczuk–Rudczyk, E. 2005. Przeksztaácenia jakoĞci wody maáej rzeki miejskiej [Water quality transformation in the small urban river]. In: Girjatowicz J.P., KoĨmiĔski C. [Eds] Hydrograficzne i meteorologiczne aspekty badaĔ wybrzeĪa Baátyku i wybranych obszarów Polski. wyd. Uniwersytet SzczeciĔski, PTG, Szczecin. p. 74. Jekatierynczuk–Rudczyk, E., ZieliĔski, P. 2004, Stan i zagroĪenia maáej rzeki nizinnej na obszarze Parku Krajobrazowego Puszczy KnyszyĔskiej [Small lowland river emergency in the KnyszyĔska Forest Landscape Park.] In: Michalczyk, Z. [Ed.] Badania geograficzne w poznaniu Ğrodowiska. Wydawnictwo Uniwersytetu Marii Curie-Skáodowskiej w Lublinie. pp. 301–306. Jekatierynczuk–Rudczyk, E., ĩuk, E. 2006. Walory krenologiczne Biaáegostoku i okolic [Crenological values in Biaáystok region] Podlaska Kultura Fizyczna, 1 (8), 29-34 Kayabak, K., Çelikn, H., Karatosun, H., AngĦn, Z., Koçbay, A. 1999. The influence of a heavily polluted urban river on the adjacent aquifer systems. Environmental Geology 38 (3), 233-243. Kondracki, J. 1998. Geografia regionalna Polski. [Regional geography of Poland.] Wyd. Nauk. PWN, Warszawa. àoszewski, H. 1983. Stosunki wodne zlewni SupraĞli. [Water conditions in SupraĞl basin. Biaáystok.] OBN, Biaáystok, 190 ss. àoszewski, H. 1995. ħródáa na terenie Biaáegostoku i potrzeba ich ochrony. [Springs in the Biaáystok and need their to protect.] Biaáostoczyzna 4, 140-153. Macioszczyk, A. 1991. Początkowe stadia antropogenicznych przeksztaáceĔ chemizmu wód podziemnych - ich ocena i interpretacja. Wspóáczesne problemy hydrogeologii [Origin stages of anthropogenic transformation groundwater quality – their estimation and interpretation. The recent problems in hydrogeology.] Mat. CPBP 04.10. SGGW AR Warszawa, 48, 254-258 [Engl. summ.]. Macioszczyk, A., Grochowski, D., PorĊbska, G. 1991. The recent problems in hydrogeology, Zanieczyszczenia antropogeniczne wód w Ĩródáach lewobrzeĪnej Warszawy. Wspóáczesne problemy hydrogeologii [Anthropogenic water pollution in the fountain in the left Vistula – river bank in Warsaw.] Mat. CPBP 04.10. SGGW AR Warszawa 48, 29-39 [Engl. summ.].

87

Musiaá, A. 1992 Studium rzeĨby glacjalnej póánocnego Podlasia [Study on the northern Podlasie glacial relief.] Wydawnictwo Uniwersytetu Warszawskiego, Warszawa [Engl. summ.]. Nagoye, E., Machiwa, J.F. 2004, The influence of land – use patterns in the Ruvu river watershed on water quality in the river system. Physics and Chemistry of the Earth 29, 1161-1166. Olguin, H.F., Puig, A., Loez, C., Salibián, A., Topalián, M.L., Castañé, P.M., Rovedatti, M.G. 2004. An integration of water physicochemistry, algal bioassays, phytoplankton, and zooplankton for ecotoxicological assessment a highly polluted lowland river. Water, Air, and Soil Pollution 155, 355 - 381. Podziaá hydrograficzny Polski 1983. [Watershed Map of Poland.] IMGW, Wydawnictwo Komunikacji i àącznoĞci, Warszawa. Pusáowska–Tyszewska, D., Tyszewski, S., Jarząbek, A. 2005. Wybrane aspekty analizy antropogenicznych oddziaáywaĔ na wody powierzchniowe i ich skutki – rok 2004 [Select aspects of anthropogenic influence on the surface water and their resultate – 2004 year.] Gospodarka Wodna 7, 275-284. Raport stan Ğrodowiska w Polsce w latach 1996-2001 2003 [Report of environmental state in Poland in 1996 - 2001 years.] IOĝ, Biblioteka Monitoringu ĝrodowiska, Warszawa. Raport o stanie Ğrodowiska województwa podlaskiego w latach 2002-2003 2004. [Report of environmental state in Podlaski Province in 2002-2003 years.] IOĝ, WIOĝ w Biaáymstoku, Biblioteka Monitoringu ĝrodowiska, Biaáystok. Samojlik, D. 1997. Przestrzenne i sezonowe zmiany skáadu chemicznego wód rzeki Biaáej [Spatial and seasonal dynamics water quality in the Biaáa River.] MSc Thesis University of Bialystok. Stan czystoĞci wòd powierzchniowych obszaru zielonych páuc Polski 1998. [Surface water quality in the Green Lungs of Poland.] Biblioteka Monitoringu ĝrodowiska, Biaáystok. Zalewski, M. 2000. Ecohydrology – the scientific background to use ecosystem properties as management tools toward sustainability of water resources. Ecological Engineering 16, 1-8. ZieliĔski, P., Górniak, A. 1999. Analizy rozpuszczonego wĊgla organicznego w wodach naturalnych [Analyses of dissolved organic carbon in natural water.] Aparatura badawcza dydaktyczna 3, 37-45.