5
But the amount of natural pollutants is negligible compared to man-made substances. Thousands of unpredictable chemicals are introduced into water basins
each year, most of which are new chemical compounds (xenobiotics). Increased
concentrations of toxic heavy metals (such as cadmium, mercury, lead, and chromium), pesticides, nitrates and phosphates, petroleum products, and surfactants can
be detected in water.
As it is known, up to 12 million tons of oil are imported into the seas and oceans
every year. Acid rains also play a role in increasing the concentrations of heavy metals in water. They are able to dissolve minerals in the soil, which leads to an increase
in the content of heavy metal ions in the water. Nuclear power plants also interfere
with radioactive waste in the water cycle. Discharge of untreated wastewater from
households leads to microbiological water pollution (Wania and Mackay 1996).
Specific pollutants that pollute water are various chemicals, pathogens, as well as
physical or sensory changes such as fever and discoloration. Although many of the
regulated chemicals and substances can be found in natural conditions (calcium,
sodium, iron, copper, manganese, etc.), concentration is usually key in determining
what is a natural constituent of water and what is a pollutant. High concentrations
of naturally occurring substances can have adverse effects on aquatic flora and
fauna (Wania and Mackay 1996; Rodriguez-Proteau and Grant 2005).
Substances that consume oxygen can be natural substances, such as plant matter
(leaves or grass), but also man-made chemicals. Other natural and anthropogenic
substances can cause turbidity, which blocks light and impedes plant growth and
clogs the gills of some fish species. Many chemicals are toxic. Pathogens can cause
waterborne diseases in both humans and animal hosts. Changes in the physical
chemistry of water include acidity (change in pH), electrical conductivity, temperature, and eutrophication. Eutrophication is the increase in the concentration of
chemical nutrients in a given ecosystem to the extent that it increases the primary
production of the ecosystem (Rodriguez-Proteau and Grant 2005). Depending on
the degree of eutrophication, there may be subsequent adverse environmental effects
such as anoxia (severe oxygen depletion) and severe reductions in water quality,
affecting fish and other animal populations. Organic and inorganic substances can
act as pollutants in water ecosystems. Organic pollutants of water are:
• Detergents
• Disinfectant by-products found in chemically disinfected drinking water, such as
chloroform
• Waste from food production processes, which may be represented by substances
that require oxygen, oils, and fats
• Insecticides and herbicides, various organohalides, and other chemical
compounds
• Petroleum hydrocarbons, including fuels (petrol, diesel, propellant, and fuel oil)
and lubricants (motor oils), as well as by-products of fuel combustion
• Waste from trees and shrubs
• Volatile organic compounds (VOCs) as industrial solvents
• Polychlorinated biphenyls (PCBs)
1 General Aspects of Environmental Degradation vs. Technological Development…
But the amount of natural pollutants is negligible compared to man-made substances. Thousands of unpredictable chemicals are introduced into water basins
each year, most of which are new chemical compounds (xenobiotics). Increased
concentrations of toxic heavy metals (such as cadmium, mercury, lead, and chromium), pesticides, nitrates and phosphates, petroleum products, and surfactants can
be detected in water.
As it is known, up to 12 million tons of oil are imported into the seas and oceans
every year. Acid rains also play a role in increasing the concentrations of heavy metals in water. They are able to dissolve minerals in the soil, which leads to an increase
in the content of heavy metal ions in the water. Nuclear power plants also interfere
with radioactive waste in the water cycle. Discharge of untreated wastewater from
households leads to microbiological water pollution (Wania and Mackay 1996).
Specific pollutants that pollute water are various chemicals, pathogens, as well as
physical or sensory changes such as fever and discoloration. Although many of the
regulated chemicals and substances can be found in natural conditions (calcium,
sodium, iron, copper, manganese, etc.), concentration is usually key in determining
what is a natural constituent of water and what is a pollutant. High concentrations
of naturally occurring substances can have adverse effects on aquatic flora and
fauna (Wania and Mackay 1996; Rodriguez-Proteau and Grant 2005).
Substances that consume oxygen can be natural substances, such as plant matter
(leaves or grass), but also man-made chemicals. Other natural and anthropogenic
substances can cause turbidity, which blocks light and impedes plant growth and
clogs the gills of some fish species. Many chemicals are toxic. Pathogens can cause
waterborne diseases in both humans and animal hosts. Changes in the physical
chemistry of water include acidity (change in pH), electrical conductivity, temperature, and eutrophication. Eutrophication is the increase in the concentration of
chemical nutrients in a given ecosystem to the extent that it increases the primary
production of the ecosystem (Rodriguez-Proteau and Grant 2005). Depending on
the degree of eutrophication, there may be subsequent adverse environmental effects
such as anoxia (severe oxygen depletion) and severe reductions in water quality,
affecting fish and other animal populations. Organic and inorganic substances can
act as pollutants in water ecosystems. Organic pollutants of water are:
• Detergents
• Disinfectant by-products found in chemically disinfected drinking water, such as
chloroform
• Waste from food production processes, which may be represented by substances
that require oxygen, oils, and fats
• Insecticides and herbicides, various organohalides, and other chemical
compounds
• Petroleum hydrocarbons, including fuels (petrol, diesel, propellant, and fuel oil)
and lubricants (motor oils), as well as by-products of fuel combustion
• Waste from trees and shrubs
• Volatile organic compounds (VOCs) as industrial solvents
• Polychlorinated biphenyls (PCBs)
1 General Aspects of Environmental Degradation vs. Technological Development…