for mercury. Actually, cadmium is a very poisonous element and especially insidious
for human beings because it is insufficiently eliminated by the body. Over a period
of years, cadmium accumulates in particular in the bones. Fatal cases of cadmium
poisoning have occurred in Japan. There is also an apparent connection between
cadmium contamination and high blood pressure.
On the average, an inhabitant in the Federal Republic of Germany ingests 0.476 mg
of cadmium a week with his food. This is almost as much as the internationally
recommended maximum limit (Ernahrungsbericht 1976). Agricultural products contaminated by fertilizers which contain up to 30 mg/kg cadmium are under particularly heated discussion. Sea products have nearly no effect on the amount of cadmium a human absorbs because he only receives 0.008 mg of cadmium from the
200 g of sea fish that the average German eats per week. This is one-sixtieth of the
total amount of cadmium taken up with food.
In such coastal areas where industrial pollution occurs or where wastes and sludges
are dumped into the sea (see Chap. 4.2) in marine seafood other than fish, high cadmium concentrations can show up which might be a human health risk. In the Bristol
Channel there is severe pollution with heavy metals from the mining district of
Southern Wales (Fig. 74); limpets (Patella vulgata) have 119 mg/kg cadmium, on dry
weight basis, equal to about 24 mg/kg on wet weight basis (peden et al. 1973). In
Kiel Harbor, mussels (Mytilus edulis) have 10-34 mg/kg cadmium (on dry weight
basis). Fortunately, mussels from the mussel culture areas in the German Wadden-Sea
have concentrations of only 1-3 mg/kg cadmium, on dry weight basis, or 0.1 mg/kg
on wet weight basis (Theede et al. 1979a). But in oysters from some oyster culture
areas higher concentrations, up to 5 mg/kg on wet weight basis, have been reported;
it has to be confirmed whether such local data have to be generalized.
When the cadmium-in-oyster question was discussed among experts in the Federal
Republic of Germany, it did not seem reasonable to work out a regulation setting
standards for the highest permissible concentration of cadmium in oysters. It seemed
a better procedure to inform the press about the risk that oysters, like certain champignons and other mushrooms from unpolluted woodland, due to special physiological capacities, can accumulate cadmium from the low concentrations in the
environment to relatively high concentrations in certain tissues of their body. In the
Federal Republic of Germany oysters are so expensive that those who like to eat
oysters can read the newspapers and decide for themselves whether or not to continue to eat oyster, and if so, to consider them as a delicatesse. Future analyses will
better inform about concentrations of cadmium in oysters and other seafood, like
cuttlefish, squid, and octopus, or in the brown meat of crabs and shrimps. Fortunately, cadmium concentrations in fm fish, which is the only marine food of great
importance, is very low. That is why no regulation in general regarding cadmium is
necessary, and why only 0.01-0.2 mg/kg of cadmium, on wet weight basis, is present
in livers from seal (Phoca vitulina) living in the German Wadden-Sea (Fig. 29).
Astonishingly high concentrations of cadmium accumulate in the liver of molluscs:
up to 2000 mg/kg in scallops (Pecten), up to 1100 mg/kg (both data on dry weight
basis) in the squid Symplectotheuthis oualaniensis which lives in the high seas where
industrial pollution cannot play any role (Martin and Flegal 1975; Bryan 1976).
Besides cadmium, the liver of these squids contains up to 1900 mg/kg of copper and
159
for human beings because it is insufficiently eliminated by the body. Over a period
of years, cadmium accumulates in particular in the bones. Fatal cases of cadmium
poisoning have occurred in Japan. There is also an apparent connection between
cadmium contamination and high blood pressure.
On the average, an inhabitant in the Federal Republic of Germany ingests 0.476 mg
of cadmium a week with his food. This is almost as much as the internationally
recommended maximum limit (Ernahrungsbericht 1976). Agricultural products contaminated by fertilizers which contain up to 30 mg/kg cadmium are under particularly heated discussion. Sea products have nearly no effect on the amount of cadmium a human absorbs because he only receives 0.008 mg of cadmium from the
200 g of sea fish that the average German eats per week. This is one-sixtieth of the
total amount of cadmium taken up with food.
In such coastal areas where industrial pollution occurs or where wastes and sludges
are dumped into the sea (see Chap. 4.2) in marine seafood other than fish, high cadmium concentrations can show up which might be a human health risk. In the Bristol
Channel there is severe pollution with heavy metals from the mining district of
Southern Wales (Fig. 74); limpets (Patella vulgata) have 119 mg/kg cadmium, on dry
weight basis, equal to about 24 mg/kg on wet weight basis (peden et al. 1973). In
Kiel Harbor, mussels (Mytilus edulis) have 10-34 mg/kg cadmium (on dry weight
basis). Fortunately, mussels from the mussel culture areas in the German Wadden-Sea
have concentrations of only 1-3 mg/kg cadmium, on dry weight basis, or 0.1 mg/kg
on wet weight basis (Theede et al. 1979a). But in oysters from some oyster culture
areas higher concentrations, up to 5 mg/kg on wet weight basis, have been reported;
it has to be confirmed whether such local data have to be generalized.
When the cadmium-in-oyster question was discussed among experts in the Federal
Republic of Germany, it did not seem reasonable to work out a regulation setting
standards for the highest permissible concentration of cadmium in oysters. It seemed
a better procedure to inform the press about the risk that oysters, like certain champignons and other mushrooms from unpolluted woodland, due to special physiological capacities, can accumulate cadmium from the low concentrations in the
environment to relatively high concentrations in certain tissues of their body. In the
Federal Republic of Germany oysters are so expensive that those who like to eat
oysters can read the newspapers and decide for themselves whether or not to continue to eat oyster, and if so, to consider them as a delicatesse. Future analyses will
better inform about concentrations of cadmium in oysters and other seafood, like
cuttlefish, squid, and octopus, or in the brown meat of crabs and shrimps. Fortunately, cadmium concentrations in fm fish, which is the only marine food of great
importance, is very low. That is why no regulation in general regarding cadmium is
necessary, and why only 0.01-0.2 mg/kg of cadmium, on wet weight basis, is present
in livers from seal (Phoca vitulina) living in the German Wadden-Sea (Fig. 29).
Astonishingly high concentrations of cadmium accumulate in the liver of molluscs:
up to 2000 mg/kg in scallops (Pecten), up to 1100 mg/kg (both data on dry weight
basis) in the squid Symplectotheuthis oualaniensis which lives in the high seas where
industrial pollution cannot play any role (Martin and Flegal 1975; Bryan 1976).
Besides cadmium, the liver of these squids contains up to 1900 mg/kg of copper and
159