9 Assessment of Pollution of Water Resources and Process of Pollution Spreading
193
part in it. Elements accumulated in the ecosystem return to circulation in various
amounts, at different times and using various mechanisms [3, 4, 28, 30, 32].
The basic phosphorus and nitrogen resources are accumulated in bottom sediments
[2–4, 33–35]. In the surface 10-cm layer of bottom sediments, there is about 90% of
phosphorus that occurs in the whole ecosystem [3]. The most important processes in
the phosphorus retention in bottom sediments are sorption and binding of this element
by iron hydroxides and addition by calcium carbonates and autogenous formation
of minerals. The water supply of biogeols contained in bottom sediments plays the
most important role during summer stagnation, mainly due to bacteria and release
mechanisms to the solution, under annealed conditions, Fe-P and Al-P [4, 30, 33, 35]
joints. This process is intensified by the mixing of bottom waters with the ones closer
to the surface, which is why the dynamics of water masses play a fundamental role in
the nutrient cycle. The average rate of vertical transport of fosfon from hypolimnion
to the photonic zone is 4 mg·m-2 per day. Swiss research shows that this transport
can take place faster and ranges from 20 to 33 mg·m-2 per day [4].
The release of phosphorus from bottom sediments located within the epilimnion is
much more important than the same process carried out in hypolimnion on the border
of sediments and water under anaerobic conditions [4]. The phosphorus exchange
rate between water and bottom sediments varies in direction and pace; depends on
the trophy level of the lake. In oligotrophic and mesotrophic tanks, phosphorus is
released into the water regardless of the aerobic conditions prevailing in the bottom
waters; in the absence of oxygen, the rate of this exchange is faster. In eutrophic lakes
in the presence of oxygen, phosphorus is absorbed by bottom sediments [4, 33].
Much smaller phosphorus reserves are found in aquatic organisms (containing
a small percentage of total nutrient resources), but due to the rapid rate of recirculation of these resources, especially in the summer, they play an important role in
the ecosystem. From consumption and the distribution of life and from the secretion
of various forms of matter by aquatic organisms comes its main part that circulates
and is subject to transformation in the ecosystem. Separation of mineral nitrogen
and phosphorus compounds by invertebrate animals is the basic mechanism of their
circulation in the water depth, as well as significant, in addition to bacterial degradation, in bottom sediments [33]. This applies even more to bacteria. Their biomass
is small, while the role in supplying the ecosystem with soluble forms of nutrients
is fundamental [3]. All processes together mean that during the summer in lakes’
epilimnion, the phosphorus circulation time is several minutes [30].
The basic source of water pollution is agriculture, and the degradation of water
resources under the influence of agricultural area pollution is a significant problem [1,
4, 7, 28, 30, 32]. Agroecosystems are characterized by open biogeochemical cycles,
significantly simplified. Therefore the losses of nutrients, mainly in the process of
water migration, are higher within them. Among pollutants discharged from agricultural areas, organic and trophic impurities predominate, lakes are thus exposed to
constantly progressing eutrophication, resulting in increased fertility [31].
The transformation of the primary landscape into the agricultural landscape has
affected the deformation of water bodies, mainly consisting of shortening and simplifying the small water cycle. There was a decrease in soil retention, deterioration of
193
part in it. Elements accumulated in the ecosystem return to circulation in various
amounts, at different times and using various mechanisms [3, 4, 28, 30, 32].
The basic phosphorus and nitrogen resources are accumulated in bottom sediments
[2–4, 33–35]. In the surface 10-cm layer of bottom sediments, there is about 90% of
phosphorus that occurs in the whole ecosystem [3]. The most important processes in
the phosphorus retention in bottom sediments are sorption and binding of this element
by iron hydroxides and addition by calcium carbonates and autogenous formation
of minerals. The water supply of biogeols contained in bottom sediments plays the
most important role during summer stagnation, mainly due to bacteria and release
mechanisms to the solution, under annealed conditions, Fe-P and Al-P [4, 30, 33, 35]
joints. This process is intensified by the mixing of bottom waters with the ones closer
to the surface, which is why the dynamics of water masses play a fundamental role in
the nutrient cycle. The average rate of vertical transport of fosfon from hypolimnion
to the photonic zone is 4 mg·m-2 per day. Swiss research shows that this transport
can take place faster and ranges from 20 to 33 mg·m-2 per day [4].
The release of phosphorus from bottom sediments located within the epilimnion is
much more important than the same process carried out in hypolimnion on the border
of sediments and water under anaerobic conditions [4]. The phosphorus exchange
rate between water and bottom sediments varies in direction and pace; depends on
the trophy level of the lake. In oligotrophic and mesotrophic tanks, phosphorus is
released into the water regardless of the aerobic conditions prevailing in the bottom
waters; in the absence of oxygen, the rate of this exchange is faster. In eutrophic lakes
in the presence of oxygen, phosphorus is absorbed by bottom sediments [4, 33].
Much smaller phosphorus reserves are found in aquatic organisms (containing
a small percentage of total nutrient resources), but due to the rapid rate of recirculation of these resources, especially in the summer, they play an important role in
the ecosystem. From consumption and the distribution of life and from the secretion
of various forms of matter by aquatic organisms comes its main part that circulates
and is subject to transformation in the ecosystem. Separation of mineral nitrogen
and phosphorus compounds by invertebrate animals is the basic mechanism of their
circulation in the water depth, as well as significant, in addition to bacterial degradation, in bottom sediments [33]. This applies even more to bacteria. Their biomass
is small, while the role in supplying the ecosystem with soluble forms of nutrients
is fundamental [3]. All processes together mean that during the summer in lakes’
epilimnion, the phosphorus circulation time is several minutes [30].
The basic source of water pollution is agriculture, and the degradation of water
resources under the influence of agricultural area pollution is a significant problem [1,
4, 7, 28, 30, 32]. Agroecosystems are characterized by open biogeochemical cycles,
significantly simplified. Therefore the losses of nutrients, mainly in the process of
water migration, are higher within them. Among pollutants discharged from agricultural areas, organic and trophic impurities predominate, lakes are thus exposed to
constantly progressing eutrophication, resulting in increased fertility [31].
The transformation of the primary landscape into the agricultural landscape has
affected the deformation of water bodies, mainly consisting of shortening and simplifying the small water cycle. There was a decrease in soil retention, deterioration of