Fróðskaparrit - 31.12.2000, Blaðsíða 142

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INDIVIDUAL ANALYSES OF MERCURY AND ORGANOCHLORINES
IN MARINE MAMMALS FORM THE FAROEISLANDS
Introduction
In 1997, the Faroese governmental agency
responsible for food safety - the Food and
Environmental Agency - undertook a
screening of environmental pollutants in
long-finned pilot whales, Globicephala
melas. The consumption of meat and blub-
ber from these animals may reasonably be
considered one of the main sources of mer-
cury and persistent organic pollutants in the
human population (Julshamn et al., 1987;
Aguilar et al., 1993; Simmonds et al.,
1994). The investigation covered 466 indi-
vidual pilot whales randomly sampled from
a total of 913 animals from a total of ten
concomitant grinds or pilot whale pods
(Butterworth, 1996). The samples were,
however, analysed as combined samples in
three pools from each of the ten grinds.
The animals were sorted according to sex
and sexual maturity. Hence, from one
grind a pool of adult females, a pool of
adult males, and a pool that included the
juveniles of both sexes were made. The
pooled muscle and blubber samples were
then analysed for mercury and organochlo-
rines as PCB, the pesticides Mirex1 and
DDT, and the metabolites, chlordanes, lin-
dane and toxaphene.
The results (Dam and Bloch, 2000) were
useful for a general indication of the
amount of pesticides and mercury burden
that these whales carry. The results re-
vealed that the average concentration of
mercury in a long-finned pilot whale pod
was 1.9 mg/kg, with some pods near 1
mg/kg and some closer to 3 mg/kg.
The results also confirmed that there is a
large, sex-based difference in the concen-
trations of the persistent organic pollutants,
with adult females nearly always having
lower concentrations of these pollutants
than the adult males. This has been shown
to be a consequence of reproduction or,
more importantly, lactation, which trans-
fers a significant proportion of the body
burden of the fat-soluble persistent
organochlorines (OC) to the offspring
(Borrell et al, ,1995). In instances where
the OC concentration in the various pools
Table 1. The table gives an overview ofthe samples analysed in the present study Talva 1. Talvan gevur eitt yvirlit yvir tey sýni, sum vórðu kannað í hesi kanningini.
Species Location Sampling date Parameter analysed No. of individuals analysed
Grey seal various locations along the coast in summer-months of 1993 to 1995 Hg, PCB, pesticides, Toxaphene 30
White-sided dolphin Klaksvík 21 August 1997 Hg, PCB, pesticides, toxaphene 28
Long-finned pilot whale Sandavágur 26 August 1997 PCB, pesticides, toxaphene 50
Long-finned pilot whale Tórshavn 24 September 1997 PCB, pesticides, toxaphene 50
Long-finned pilot whale Tórshavn 13 November 1997 Hg 50
Long-finned pilot whale Leynar 2 December 1997 Hg 50