88
N. W. MOORE
most imprecise but several have been attempted, notably by Arrington
(1956). Rudd (1964) estimates that the total annual production of DDT
approaches 225 000 000 Ib. The total amount of a given pesticide in the
environment depends on its persistence in atmosphere, water, soils and
living organisms. At any one time the tonnage of a persistent pesticide
like DDT, which may take several years to disappear, will greatly exceed the amount derived from annual production figures. The total
amount of DDT on the earth’s surface is perhaps of the order of
1 0 0 0 000 tons. Fifty thousand tons of insecticides are now used in
malaria control and eradication schemes alone each year (WHO Report
1964). Useful estimates of pesticide imports into African countries etc.
are reported from time to time in the Economics Section of “Pesticides
Abstracts and News Summaries”, edited by G. Ordish and produced by
the Department of Technical Cooperation, London. Since persistent
pesticides become concentrated in surface films, muds and lipid material
in organisms, the distribution of these substances is undoubtedly most
irregular throughout the world; therefore estimates of mean concentrations derived for example by dividing the contents of the oceans by the
tonnage of organochlorine insecticides are virtually meaningless.’ It
should be noted that these pesticides will be concentrated in those
places, e.g. surface waters, where they are most available to living
organisms. This should be taken into account when considering the
significance of residues in marine animals both in temperate and polar
regions. We are very far from being able to measure the size of the
pesticide factor on a global scale, yet this is an important requirement
in all large-scale appraisals of pesticide effects. The participants of the
North Atlantic Treaty Organization Advanced Study Institute on
Pesticides in the Environment held in 1965 drew attention to this fact
in their General Statement (see Moore, 1966). It is greatly to be hoped
that the relevant national and international agencies will take the steps
to make the information on pesticide use available to all concerned.
IV. THE MAIN CHARACTERISTICS OF PESTICIDES AS AN
ECOLOGICAL FACTOR
A. COMMON CHARACTERISTICS
1. General
There are, very approximately, 200 pesticides in common use today,
of which about 90% are synthetic organic compounds, 5% are inorganic
compounds like mercurous chloride and 5% are naturally occurring
organic compounds like pyrethrum. Some of the latter are also synthesized. Pesticides can be classified according to their function (herbicides, insecticides, eto.), or their form of application (sprays, dusts,
granules, seed dressings, etc.), or their chemical nature (organochlorines,
N. W. MOORE
most imprecise but several have been attempted, notably by Arrington
(1956). Rudd (1964) estimates that the total annual production of DDT
approaches 225 000 000 Ib. The total amount of a given pesticide in the
environment depends on its persistence in atmosphere, water, soils and
living organisms. At any one time the tonnage of a persistent pesticide
like DDT, which may take several years to disappear, will greatly exceed the amount derived from annual production figures. The total
amount of DDT on the earth’s surface is perhaps of the order of
1 0 0 0 000 tons. Fifty thousand tons of insecticides are now used in
malaria control and eradication schemes alone each year (WHO Report
1964). Useful estimates of pesticide imports into African countries etc.
are reported from time to time in the Economics Section of “Pesticides
Abstracts and News Summaries”, edited by G. Ordish and produced by
the Department of Technical Cooperation, London. Since persistent
pesticides become concentrated in surface films, muds and lipid material
in organisms, the distribution of these substances is undoubtedly most
irregular throughout the world; therefore estimates of mean concentrations derived for example by dividing the contents of the oceans by the
tonnage of organochlorine insecticides are virtually meaningless.’ It
should be noted that these pesticides will be concentrated in those
places, e.g. surface waters, where they are most available to living
organisms. This should be taken into account when considering the
significance of residues in marine animals both in temperate and polar
regions. We are very far from being able to measure the size of the
pesticide factor on a global scale, yet this is an important requirement
in all large-scale appraisals of pesticide effects. The participants of the
North Atlantic Treaty Organization Advanced Study Institute on
Pesticides in the Environment held in 1965 drew attention to this fact
in their General Statement (see Moore, 1966). It is greatly to be hoped
that the relevant national and international agencies will take the steps
to make the information on pesticide use available to all concerned.
IV. THE MAIN CHARACTERISTICS OF PESTICIDES AS AN
ECOLOGICAL FACTOR
A. COMMON CHARACTERISTICS
1. General
There are, very approximately, 200 pesticides in common use today,
of which about 90% are synthetic organic compounds, 5% are inorganic
compounds like mercurous chloride and 5% are naturally occurring
organic compounds like pyrethrum. Some of the latter are also synthesized. Pesticides can be classified according to their function (herbicides, insecticides, eto.), or their form of application (sprays, dusts,
granules, seed dressings, etc.), or their chemical nature (organochlorines,