126
A. Solarczyk
mgCaCO 3 /L], Skawa and Tanew). The exception is the rivers of the Wisłok river
catchment, where the total hardness (259 mgCaCO 3 /L) is higher, and this increase
is likely caused by the high content of calcium and magnesium in flysch rocks in the
Rzeszów region [6]. Low total hardness is also found in river catchments covering
the Sudete region and forest complexes of Dolny ´
Sl˛ ask (Nysa Kłodzka, Bóbr [90
mgCaCO 3 /L], Nysa Łu˙ zycka). Central Pomorze is an area that stands out among
Poland’s lowland areas; in the Łupawa, Słupia, and Wieprza river catchments, average
total hardness did not exceed 170 mg of CaCO 3 /L. Elsewhere, in the lowland regions
of Wielkopolska, Kujawia, Mazowsze, Podlasie and Lubelszczyzna, total hardness in
rivers is high, which is caused by the systematic liming of soil. Within these regions,
there is a particularly high content of calcium and magnesium ions in the catchment
of the Wełna and Zgłowi˛ aczka rivers and the Obra Canal, as well as in the subcatchments of the upper Note´ c, middle Warta and lower Vistula. The high total hardness
of the ´
Sl˛ e˙ za river catchment (Dolny ´
Sl˛ ask) is probably caused by agrotechnical treatments. The enrichment of the rivers of the Huczwa river catchment (Zamo´ s´ c region)
with calcium and magnesium ions is associated with the lithology of the substrate
containing limestone rocks. In the Kłodnica catchment, the high calcium and magnesium content in rivers may be caused by the inflow of pollutants from mine drainage
and chemical plants in Górny ´
Sl˛ ask. The greatest hardness is found in Martwa Wisła
(Table 6.2). Gda´ nsk’s chemical industry zone is located along its banks.
The average content of easily decomposed organic matter in Poland’s rivers,
as measured using the BOD 5 index, was low and poorly differentiated regionally
(Fig. 6.3). The highest BOD 5 values were determined in the rivers of Wielkopolska
(e.g., the Barycz river catchment, the middle Warta subcatchment), Mazowsza (the
Bzura catchment, the subcatchment of left tributaries of the middle Vistula), and
Górny ´
Sl˛ ask (the Kłodnica catchment). In Wielkopolska and Mazowsza, there is a
predominance of small towns and villages, which may be the source of the organic
matter contained in sewage. The higher loads of easily decomposed organic matter
in rivers of Górny ´
Sl˛ ask are due to the region’s very high population density, and a
significant quantity of sewage discharged from municipal sewage treatment plants.
River catchments in which forest areas prevail and population density is low
have low organic matter contents. The lowest average BOD 5 values were found
in mountain rivers (the catchments of the Soła, Skawa, Raba, and Dunajec rivers),
rivers of north-eastern Poland (the Nurzec, Biebrza, Rospuda, Czarna Ha´ ncza and
Omulew rivers) and rivers of western Pomorze (the catchments of the Drawa, Pars˛ eta
and Rega) (Tables 6.3 and 6.4).
Organic carbon compound content in Polish rivers varies greatly between regions
(Fig. 6.4). Low TOC values are typical of rivers of the Carpathian and Sudete mountains and foothills, as well as rivers of Dolny ´
Sl˛ ask and central and western Pomorze.
In these regions, the average TOC concentration does not exceed 7.8 mgC/L. The
lowest TOC content is found in rivers of the Soła catchment (2.2 mgC/L), the Dunajec
(2.4 mgC/L) and the Skawa (2.9 mgC/L). The highest TOC concentrations (> 9.9
mgC/L) occur in the rivers of eastern and north-eastern Poland (e.g., the Krzna,
upper Narew and W˛ egorapa catchments), as well as in Wielkopolska and western
and north-western Poland. Particularly high organic carbon contents are found in the
A. Solarczyk
mgCaCO 3 /L], Skawa and Tanew). The exception is the rivers of the Wisłok river
catchment, where the total hardness (259 mgCaCO 3 /L) is higher, and this increase
is likely caused by the high content of calcium and magnesium in flysch rocks in the
Rzeszów region [6]. Low total hardness is also found in river catchments covering
the Sudete region and forest complexes of Dolny ´
Sl˛ ask (Nysa Kłodzka, Bóbr [90
mgCaCO 3 /L], Nysa Łu˙ zycka). Central Pomorze is an area that stands out among
Poland’s lowland areas; in the Łupawa, Słupia, and Wieprza river catchments, average
total hardness did not exceed 170 mg of CaCO 3 /L. Elsewhere, in the lowland regions
of Wielkopolska, Kujawia, Mazowsze, Podlasie and Lubelszczyzna, total hardness in
rivers is high, which is caused by the systematic liming of soil. Within these regions,
there is a particularly high content of calcium and magnesium ions in the catchment
of the Wełna and Zgłowi˛ aczka rivers and the Obra Canal, as well as in the subcatchments of the upper Note´ c, middle Warta and lower Vistula. The high total hardness
of the ´
Sl˛ e˙ za river catchment (Dolny ´
Sl˛ ask) is probably caused by agrotechnical treatments. The enrichment of the rivers of the Huczwa river catchment (Zamo´ s´ c region)
with calcium and magnesium ions is associated with the lithology of the substrate
containing limestone rocks. In the Kłodnica catchment, the high calcium and magnesium content in rivers may be caused by the inflow of pollutants from mine drainage
and chemical plants in Górny ´
Sl˛ ask. The greatest hardness is found in Martwa Wisła
(Table 6.2). Gda´ nsk’s chemical industry zone is located along its banks.
The average content of easily decomposed organic matter in Poland’s rivers,
as measured using the BOD 5 index, was low and poorly differentiated regionally
(Fig. 6.3). The highest BOD 5 values were determined in the rivers of Wielkopolska
(e.g., the Barycz river catchment, the middle Warta subcatchment), Mazowsza (the
Bzura catchment, the subcatchment of left tributaries of the middle Vistula), and
Górny ´
Sl˛ ask (the Kłodnica catchment). In Wielkopolska and Mazowsza, there is a
predominance of small towns and villages, which may be the source of the organic
matter contained in sewage. The higher loads of easily decomposed organic matter
in rivers of Górny ´
Sl˛ ask are due to the region’s very high population density, and a
significant quantity of sewage discharged from municipal sewage treatment plants.
River catchments in which forest areas prevail and population density is low
have low organic matter contents. The lowest average BOD 5 values were found
in mountain rivers (the catchments of the Soła, Skawa, Raba, and Dunajec rivers),
rivers of north-eastern Poland (the Nurzec, Biebrza, Rospuda, Czarna Ha´ ncza and
Omulew rivers) and rivers of western Pomorze (the catchments of the Drawa, Pars˛ eta
and Rega) (Tables 6.3 and 6.4).
Organic carbon compound content in Polish rivers varies greatly between regions
(Fig. 6.4). Low TOC values are typical of rivers of the Carpathian and Sudete mountains and foothills, as well as rivers of Dolny ´
Sl˛ ask and central and western Pomorze.
In these regions, the average TOC concentration does not exceed 7.8 mgC/L. The
lowest TOC content is found in rivers of the Soła catchment (2.2 mgC/L), the Dunajec
(2.4 mgC/L) and the Skawa (2.9 mgC/L). The highest TOC concentrations (> 9.9
mgC/L) occur in the rivers of eastern and north-eastern Poland (e.g., the Krzna,
upper Narew and W˛ egorapa catchments), as well as in Wielkopolska and western
and north-western Poland. Particularly high organic carbon contents are found in the