High mercury concentrations are, of course, encountered in fish-feeding sea birds and
in seals, because these animals reach great ages. Apparently they take up more mercury with their food than they are able to eliminate, and therefore accumulate more
mercury in their tissues from year to year. Examples of high mercury concentrations
in sea birds and seals from polluted coastal areas have been provided in Chapter 3.2.
However, high mercury concentrations have been found also in animals which live far
away from any source of pollution on the high seas.
It seemed ironic: mercury was found, in 1970, in the liver extract an American firm
intended to market as highly natural and unpolluted, because they had used the liver
of Callorhinus ursinus fur seals from the Pribiloff Islands in the North Pacific. The
livers of the adult animals, however, contain 3-19 mg/kg of mercury. That is less
than the amount found in the livers of fur seals off the coast of Washington State
(up to 172 mg/kg) , but more than that found in most marine animal life (Anas
1974).
High concentrations of mercury are regularly found in marine bird life: 1-5 mg/kg
and occasionally up to 20 mg/kg in goosander (Mergus merganser), guillemot (Urifl
aalge), kittiwakes (Rissa tridactyla), fulmars (Fulmaris glacia/is), skuas (Stercorarius),
and eiderducks (Somateria mollissima). A Finnish women became ill with mercury
poisoning after eating fairly large amounts of goosander eggs which she had collected
on a deserted skerry far from any source of pollution (Nuorteva 1971).
The regulations regarding maximum permissible concentrations of mercury in fish
and other seafood are not very sound (Gerlach 1978). Delicatesses should be eaten in
small quantities. Instead of regulations it would be better to make the public aware
that some marine food, even if it comes from unpolluted areas, may have high mercury concentrations, but that these do not matter much as long as one eats small
quantities only of such food like swordfish or shark steak or gull eggs. Since Canada
has had a regulation forbidding the sale of fish with more than 0.5 mg/kg of mercury,
swordfish has been smuggled into the country in large quantities. Since 1979 swordfish is legal again in Canada in spite of its mercury.
It would be interesting to know how eskimos living in Greenland· and depending
in their diet to a large proportion on sea food manage regarding the mercury
problem.
8.3 Mercury in the Water of the World's Oceans
Even up to few years ago, chemists agreed that concentrations of mercury from
30-50 ngfl were present, with a variation of 10-140 ng/I, in uncontaminated ocean
water. If, however, analyses are made taking every precaution known, lower concentrations show: for the Northeast Atlantic, an average of 13 ng/l with a variation of
3-20 ng/l; for the Northwest Atlantic, 7 ng/I with a variation of 6-110 ng/I (Fitzgerald and Lyons 1975). An average concentration of only 6.9 ng/l was also found in
the North Sea with a variation in the individual measurements of between 3.4 and
22 ng/l (Baker 1977). Aside from the higher amounts in the Irish Sea and in the
immediate vicinity of river mouths and points of effluent introduction, only very
small differences have been noted regionally (Fig. 80). In the course of these analyses
151
in seals, because these animals reach great ages. Apparently they take up more mercury with their food than they are able to eliminate, and therefore accumulate more
mercury in their tissues from year to year. Examples of high mercury concentrations
in sea birds and seals from polluted coastal areas have been provided in Chapter 3.2.
However, high mercury concentrations have been found also in animals which live far
away from any source of pollution on the high seas.
It seemed ironic: mercury was found, in 1970, in the liver extract an American firm
intended to market as highly natural and unpolluted, because they had used the liver
of Callorhinus ursinus fur seals from the Pribiloff Islands in the North Pacific. The
livers of the adult animals, however, contain 3-19 mg/kg of mercury. That is less
than the amount found in the livers of fur seals off the coast of Washington State
(up to 172 mg/kg) , but more than that found in most marine animal life (Anas
1974).
High concentrations of mercury are regularly found in marine bird life: 1-5 mg/kg
and occasionally up to 20 mg/kg in goosander (Mergus merganser), guillemot (Urifl
aalge), kittiwakes (Rissa tridactyla), fulmars (Fulmaris glacia/is), skuas (Stercorarius),
and eiderducks (Somateria mollissima). A Finnish women became ill with mercury
poisoning after eating fairly large amounts of goosander eggs which she had collected
on a deserted skerry far from any source of pollution (Nuorteva 1971).
The regulations regarding maximum permissible concentrations of mercury in fish
and other seafood are not very sound (Gerlach 1978). Delicatesses should be eaten in
small quantities. Instead of regulations it would be better to make the public aware
that some marine food, even if it comes from unpolluted areas, may have high mercury concentrations, but that these do not matter much as long as one eats small
quantities only of such food like swordfish or shark steak or gull eggs. Since Canada
has had a regulation forbidding the sale of fish with more than 0.5 mg/kg of mercury,
swordfish has been smuggled into the country in large quantities. Since 1979 swordfish is legal again in Canada in spite of its mercury.
It would be interesting to know how eskimos living in Greenland· and depending
in their diet to a large proportion on sea food manage regarding the mercury
problem.
8.3 Mercury in the Water of the World's Oceans
Even up to few years ago, chemists agreed that concentrations of mercury from
30-50 ngfl were present, with a variation of 10-140 ng/I, in uncontaminated ocean
water. If, however, analyses are made taking every precaution known, lower concentrations show: for the Northeast Atlantic, an average of 13 ng/l with a variation of
3-20 ng/l; for the Northwest Atlantic, 7 ng/I with a variation of 6-110 ng/I (Fitzgerald and Lyons 1975). An average concentration of only 6.9 ng/l was also found in
the North Sea with a variation in the individual measurements of between 3.4 and
22 ng/l (Baker 1977). Aside from the higher amounts in the Irish Sea and in the
immediate vicinity of river mouths and points of effluent introduction, only very
small differences have been noted regionally (Fig. 80). In the course of these analyses
151