significantly contribute to this chronic lead burden. The average citizen of the Federal
Republic of Germany takes up, with food, 39 mg of lead per week. But out of this
quantity only 0.02 mg are derived from the 200 g of fish the average citizen eats per
week (Erniihrungsbericht 1976). Lead uptake from other food, from drinking water,
from car exhaust and cigarette smoke, from contact with paint and glazes, with paper
and metal is much more important. Marine fish contains only small concentrations of
lead, and therefore even the fish-eating seal does not accumulate larger concentrations of lead in its liver (Fig. 29).
In Earth crust material lead is much more abundant than mercury and cadmium. Man
has been using lead for 4000 years, and there are estimates that even before the year
1850 about 70 million t of lead had been smelted, and 130 million t more from 1850
to 1950. At present about 3.5 million t of lead are mined every year. During roasting
and smelting of lead ore in order to fabricate metallic lead, large amounts of lead
dust reach the atmosphere, and estimates are that annually about 3000 t of lead from
such processes could reach the oceans via the atmosphere. Approximately 10 million t
of lead have been converted, during the past 40 years, to tetraethyllead. In 1970,
about 400,000 t of lead in tetraethyllead, have been used as an anti-knock agent with
car gasoline. After the gasoline has been burned, the lead is left over and reaches the
atmosphere as fine dust particles. Estimates are that annually 37,000 t of lead from
gasoline reach the oceans (Patterson et al. 1976). More lead comes to the oceans
from road runoff, from paints and from weathering of lead surfaces, mostly via the
rivers. However, much of the lead mined is used in metallic form and is rather resistant against leaching and weathering; therefore it is not permitted to assume that a
large fraction of the mining product will go to the oceans, as is the case with mercury.
If modern analytical techniques give reliable results, lead concentration in unpolluted
oceanic waters is only about 2 ng/l. The water of all oceans together then contains
only 2.8 million t of lead, less than the annual production of the lead mines
(Table 36).
Lead, however, is difficult to analyze in seawater. There is a great risk of measuring,
instead of the seawater concentration, lead introduced into the measuring system
with sampling gear, impurities of chemicals, or from other sources. In 1973, subsamples of the same seawater sample were sent to nine experienced laboratories all
over the world. The results of lead analysis were strongly divergent, and some results
were ten times higher than the value that had been obtained by isotope dilution
methods, Le., 80 ng/l, in seawater sampled off the polluted coast of California (Anon
1974). Concentrations in unpolluted coastal waters are about 10-40 ng/l but concentrations in water from the open ocean are only 1-2 ng/l (Burnett and Patterson
1980; Schaule and Patterson 1980). The isotopic composition oflead in coastal seawater gives a hint that a large percentage consists of lead from lead mining (Stukas
and Wong 1981).
Due to the analytical difficulties, there are no time series of seawater lead concentrations available which could document an increase of lead concentration with time.
Analyses should be repeated which have been made with ice from Greenland glaciers
and demonstrate that ice which formed before 1750 has only 0.02IJg/kg of lead, and
that ice from 1968 contains ten times higher concentrations (Murozumi et al. 1969).
Data from anoxic Santa Barbara Basin are not convincing, because an increase in the
161
Republic of Germany takes up, with food, 39 mg of lead per week. But out of this
quantity only 0.02 mg are derived from the 200 g of fish the average citizen eats per
week (Erniihrungsbericht 1976). Lead uptake from other food, from drinking water,
from car exhaust and cigarette smoke, from contact with paint and glazes, with paper
and metal is much more important. Marine fish contains only small concentrations of
lead, and therefore even the fish-eating seal does not accumulate larger concentrations of lead in its liver (Fig. 29).
In Earth crust material lead is much more abundant than mercury and cadmium. Man
has been using lead for 4000 years, and there are estimates that even before the year
1850 about 70 million t of lead had been smelted, and 130 million t more from 1850
to 1950. At present about 3.5 million t of lead are mined every year. During roasting
and smelting of lead ore in order to fabricate metallic lead, large amounts of lead
dust reach the atmosphere, and estimates are that annually about 3000 t of lead from
such processes could reach the oceans via the atmosphere. Approximately 10 million t
of lead have been converted, during the past 40 years, to tetraethyllead. In 1970,
about 400,000 t of lead in tetraethyllead, have been used as an anti-knock agent with
car gasoline. After the gasoline has been burned, the lead is left over and reaches the
atmosphere as fine dust particles. Estimates are that annually 37,000 t of lead from
gasoline reach the oceans (Patterson et al. 1976). More lead comes to the oceans
from road runoff, from paints and from weathering of lead surfaces, mostly via the
rivers. However, much of the lead mined is used in metallic form and is rather resistant against leaching and weathering; therefore it is not permitted to assume that a
large fraction of the mining product will go to the oceans, as is the case with mercury.
If modern analytical techniques give reliable results, lead concentration in unpolluted
oceanic waters is only about 2 ng/l. The water of all oceans together then contains
only 2.8 million t of lead, less than the annual production of the lead mines
(Table 36).
Lead, however, is difficult to analyze in seawater. There is a great risk of measuring,
instead of the seawater concentration, lead introduced into the measuring system
with sampling gear, impurities of chemicals, or from other sources. In 1973, subsamples of the same seawater sample were sent to nine experienced laboratories all
over the world. The results of lead analysis were strongly divergent, and some results
were ten times higher than the value that had been obtained by isotope dilution
methods, Le., 80 ng/l, in seawater sampled off the polluted coast of California (Anon
1974). Concentrations in unpolluted coastal waters are about 10-40 ng/l but concentrations in water from the open ocean are only 1-2 ng/l (Burnett and Patterson
1980; Schaule and Patterson 1980). The isotopic composition oflead in coastal seawater gives a hint that a large percentage consists of lead from lead mining (Stukas
and Wong 1981).
Due to the analytical difficulties, there are no time series of seawater lead concentrations available which could document an increase of lead concentration with time.
Analyses should be repeated which have been made with ice from Greenland glaciers
and demonstrate that ice which formed before 1750 has only 0.02IJg/kg of lead, and
that ice from 1968 contains ten times higher concentrations (Murozumi et al. 1969).
Data from anoxic Santa Barbara Basin are not convincing, because an increase in the
161