Fróðskaparrit - 31.12.2000, Page 144

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INDIVIDUAL ANALYSES OF MERCURY AND ORGANOCHLORINES
IN MARINE MAMMALS FORM THE FAROEISLANDS
general, the occurrence of these pollutants
in marine mammals that use Faroese waters
as a part-time feeding and breeding area, as
in the case of the whales, and as a possibly
permanent residence area, as in the case of
the grey seals. It further provides the con-
fidence limits that must be defined in order
to make meaningful comparison between
Table 3. The results ofthe mercury analyses are
given as mean values including standard deviation
(bold), minimum and maximum values, in mg/kg
muscle ww. The results are given bothfor the
whole sample ofeach species or each school, and
for thefour subgroups offemales and males, adults
and juveniles, separately.
Talva 3. Urslitini av kyksilvurskanningunura eru
víst sum miðalvirði og standardfrávik (við feitari
skrift), lægst og hægst, í mg/kg av tvøsti.Úrslitini
eru víst bæði fyri øll sýni úr eini grind eins og fyri
teir fýra undirbólkarnar av hon- og hannhvølum,
hvølpum og vaksnum, hvør sær.
Hg, mg/ all adult juv. adult juv.
kg muscle females females males males
Pilot whale Tórs íavn
13-11-97 2.82 3.37 1.45 3.46 2.29
std. dev 1.16 1.00 1.00 1.28 0.76
min 0.68 1.73 0.68 2.07 0.86
max 5.94 5.79 3.15 5.94 3.50
Pilot whale Leyn ar
2-12-97 1.43 1.70 0.79 1.75 0.90
std. dev 0.59 0.44 0.45 0.14 0.50
min 0.19 0.42 0.19 1.59 0.30
max 2.99 2.99 1.31 1.86 1.43
W.-sided
dolphins 0.94 1.25 0.41 1.00 1.45
std. dev 0.40 0.17 0.29 0.25 na
min 0.07 1.05 0.07 0.50 na
max 1.47 1.47 0.84 1.37 na
Grey seals0.73 0.84 0.37 2.31 0.37
std. dev 0.86 0.40 0.27 2.22 0.26
min 0.15 0.23 0.16 0.42 0.15
max 4.76 1.51 0.92 4.76 0.90
the results of the 1997 screening and the
major pilot whale study conducted in 1986-
88 (Donovan et al., 1993). In other words,
the current study will be a valuable tool for
detecting whether the concentration of
these pollutants has increased, is constant,
or - as has been observed in other areas -
has indeed decreased.
Methods and materials
Sorting by age and sex groups
In order to compare the various pods and
species, the results have been presented for
groups of individuals of defined size (or
age) and sex. The sorting criteria for the
various species are given in the separate
sections below. The locations and date or
time period of sampling as well as the total
number of individuals from which samples
were taken are given in Table 1. The de-
scriptive parameters of these individuals,
seen as subgroups, are given in Table 2.
Pilot whale samples
Tissue samples of long-finned pilot whale
were collected in connection with the grind
as described elsewhere (Dam and Bloch,
2000). From each grind, a sub-sample was
picked of ideally 50 individuals, but fewer
were also accepted if so determined by the
size of the grind. The selection of the indi-
viduals in the sub-sample was random in
the sense that there were no guidelines as to
which individual should be included. Sam-
ples were normally stored in Minigrip
polyethylene bags at <-18°C until sub-sam-
ples of a few grams were taken for the
analyses. With the blubber samples, care
was taken to exclude from the sub-samples