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polytion relative to the geographic poles, the implication of polar wandering is
that during geological time continents systematically occupied other positions. ~continental displacement and ~plate tectonics.
pollen microspores of seed plants, carried by wind, insects and rarely water,
with a very resistent organic outer wall (exine); very useful for stratigraphic
and paleoecologic purposes, because of its good preservation and wide distribution by air and water.
pollutant any chemical substance from outside the system, whether of natural
or anthropogenic origin, with an impact on biological processes in the system. ~pollution and ~contaminant.
pollution (marine) is the introduction by man, directly or indirectly, of substances or energy into the marine environment (including estuaries), with
such deleterious effects as: harm to living resources, hazards to human
health, hindrance to marine activities, impairing the quality of seawater, and
reduction of amenities (as defined under the Intergovernmental Oceanographic Commission, IOC). Pollution effects are exerted at any integration
or organization level in the natural environment: on molecular and cellular
levels, on physiological processes in organs and organisms, on behavior of
individuals, populations or separate parts of them, on habitats and ecosystems. Pollution legislation means making or enacting laws concerning pollution; or a law or a body of laws enacted, with respect to pollution. Thermal
pollution effects are due to unnatural, man-made temperature (thermal)
changes in a system; radioactive pollution is the presence of either natural
or radioactive substances with toxic or nuisance effects. When there is no
noticeable effect of these substances, the term contamination is applicable.
Radioactive pollution, or contamination, of the marine environment is of
four types: fallout (radioactive) from bomb-test and nuclear experiments, dumping of solid low-level wastes, liquid effluents from nuclear reprocessing
plants and cooling water of nuclear power stations. Fallout precipitates have
globally been the major contamination, but are gradually decreasing due to
decay since 1963, when above-ground experiments of this kind were practically stopped. Dumping in the sea of solid wastes has also been halted due
to national and international political pressure. Liquid effluents from reprocessing plants, like those in Sellafield (UK) and La Hague (F), consistently
contain radionuclides, which are released under strict national regulations. In
principle, nuclear power plants may only release cooling water which contains for instance small amounts of neutron-induced radionuclides not
exceeding permissible levels.
poly- prefix meaning many.
polytion relative to the geographic poles, the implication of polar wandering is
that during geological time continents systematically occupied other positions. ~continental displacement and ~plate tectonics.
pollen microspores of seed plants, carried by wind, insects and rarely water,
with a very resistent organic outer wall (exine); very useful for stratigraphic
and paleoecologic purposes, because of its good preservation and wide distribution by air and water.
pollutant any chemical substance from outside the system, whether of natural
or anthropogenic origin, with an impact on biological processes in the system. ~pollution and ~contaminant.
pollution (marine) is the introduction by man, directly or indirectly, of substances or energy into the marine environment (including estuaries), with
such deleterious effects as: harm to living resources, hazards to human
health, hindrance to marine activities, impairing the quality of seawater, and
reduction of amenities (as defined under the Intergovernmental Oceanographic Commission, IOC). Pollution effects are exerted at any integration
or organization level in the natural environment: on molecular and cellular
levels, on physiological processes in organs and organisms, on behavior of
individuals, populations or separate parts of them, on habitats and ecosystems. Pollution legislation means making or enacting laws concerning pollution; or a law or a body of laws enacted, with respect to pollution. Thermal
pollution effects are due to unnatural, man-made temperature (thermal)
changes in a system; radioactive pollution is the presence of either natural
or radioactive substances with toxic or nuisance effects. When there is no
noticeable effect of these substances, the term contamination is applicable.
Radioactive pollution, or contamination, of the marine environment is of
four types: fallout (radioactive) from bomb-test and nuclear experiments, dumping of solid low-level wastes, liquid effluents from nuclear reprocessing
plants and cooling water of nuclear power stations. Fallout precipitates have
globally been the major contamination, but are gradually decreasing due to
decay since 1963, when above-ground experiments of this kind were practically stopped. Dumping in the sea of solid wastes has also been halted due
to national and international political pressure. Liquid effluents from reprocessing plants, like those in Sellafield (UK) and La Hague (F), consistently
contain radionuclides, which are released under strict national regulations. In
principle, nuclear power plants may only release cooling water which contains for instance small amounts of neutron-induced radionuclides not
exceeding permissible levels.
poly- prefix meaning many.