Cu
9/kg
16
15
• ,Central Callforma
14
.'Southern California
13
12
11
10
•
9
8
7
6
5
•
4
'.'
•
.
3
. .
2
0
•
•
•
•
•
•
•
90
Ag mg/kg
Fig. 83. Squids (Cephalopoda) store up extremely
high amounts of cadmium,
together with silver and
copper, in their liver, There
is a strong correlation
between concentrations of
silver and copper in the
liver of the squid Loligo
opalescens which lives off
the coasts of California.
Data refer to dry weight
(Martin and Flegal 1975)
up to 40 mg/kg of silver (Fig. 83). Copper is a compound of hemocyanine, the characteristic blood pigment of gastropod and cephalopod molluscs. It is possible that cadmium and silver are channeled into the squids by the same mechanism which allows
them to take up the copper which is essential for their oxygen transport system.
In Chapter 7.3 it has been explained that high cadmium concentrations occur in the
sea-skater Halobates, a marine insect from the family of pond-skaters, and in petrels,
both animals of the high seas. The explanation of high cadmium concentrations in
these animals is probably an enrichment with cadmium of the surface layer of the sea.
High cadmium concentrations as in these animals and in oceanic squids have, according to our present knowledge, nothing to do with marine pollution. They are natural
phenomena, All the mines of the world together have a cadmium production of only
about 15,000 t per year. The amounts of cadmium in the total water masses of the
world ocean, at 100 ng/I(Fig. 75), are probably in the range ofi40 million t (Table 36).
It is highly improbable that man has influenced the cadmium concentration in the
oceans. Local introductions into coastal areas, however, must be forbidden, because
cadmium may show up in marine seafood.
8.7 Contamination of the Oceans with Lead
From various calculations there is reason to suspect that lead concentrations in all
organisms, land, freshwater, and marine, have increased 20-fold during the past few
centuries and are now in the range of 0.1 mg/kg wet weight. It seems even that lead
concentrations in the average citizen in developed countries are high enough to result
in first symptoms of poisoning of the nervous system. However: marine food does not
160
9/kg
16
15
• ,Central Callforma
14
.'Southern California
13
12
11
10
•
9
8
7
6
5
•
4
'.'
•
.
3
. .
2
0
•
•
•
•
•
•
•
90
Ag mg/kg
Fig. 83. Squids (Cephalopoda) store up extremely
high amounts of cadmium,
together with silver and
copper, in their liver, There
is a strong correlation
between concentrations of
silver and copper in the
liver of the squid Loligo
opalescens which lives off
the coasts of California.
Data refer to dry weight
(Martin and Flegal 1975)
up to 40 mg/kg of silver (Fig. 83). Copper is a compound of hemocyanine, the characteristic blood pigment of gastropod and cephalopod molluscs. It is possible that cadmium and silver are channeled into the squids by the same mechanism which allows
them to take up the copper which is essential for their oxygen transport system.
In Chapter 7.3 it has been explained that high cadmium concentrations occur in the
sea-skater Halobates, a marine insect from the family of pond-skaters, and in petrels,
both animals of the high seas. The explanation of high cadmium concentrations in
these animals is probably an enrichment with cadmium of the surface layer of the sea.
High cadmium concentrations as in these animals and in oceanic squids have, according to our present knowledge, nothing to do with marine pollution. They are natural
phenomena, All the mines of the world together have a cadmium production of only
about 15,000 t per year. The amounts of cadmium in the total water masses of the
world ocean, at 100 ng/I(Fig. 75), are probably in the range ofi40 million t (Table 36).
It is highly improbable that man has influenced the cadmium concentration in the
oceans. Local introductions into coastal areas, however, must be forbidden, because
cadmium may show up in marine seafood.
8.7 Contamination of the Oceans with Lead
From various calculations there is reason to suspect that lead concentrations in all
organisms, land, freshwater, and marine, have increased 20-fold during the past few
centuries and are now in the range of 0.1 mg/kg wet weight. It seems even that lead
concentrations in the average citizen in developed countries are high enough to result
in first symptoms of poisoning of the nervous system. However: marine food does not
160