Fróðskaparrit - 01.07.2004, Síða 123

KYKSILVUR í FØROYUM - EIN GJØGNUMGONGD AV TØKUM DÁTUM
121
Whale ID Size SEX Hg, mg/kg ww
no. (skinn) Muscle Kidney Liver
14 8 female 4,7 11,2 230
(3) (2) (19)
20 12 male 7,0 5,8 107
(5) (1) (9)
25 13 male 3,5 5,4 63
(2) (1) (5)
median (n=37) 5 1,45 5,4 12,1
Tahle 16 Mercury in muscle, kidney and liver tissuefrom the grind in Sandagerði 28 Aug 1979. The numbers in
parentheses are the ratio of the mercury concentration in the specifted individual and tissue to tliat of tlte median
for the sample. (HSjoumal 1977-79).
(n=2) (Heilsufrøðiliga Starvsstovan, un-
publ.)
In 1997, sampling was done in 10 out of
15 whale hunting events. In this sampling
466 whales were included, but the analyses
were mainly đone on pooled samples (Dam
and Bloch, 2000). In Table 15, the results of
the mercury analyses on pilot whale muscle
(=meat) from 1997 and onward is shown.
In the table, results are presented for the
pods as well as for the adult males and fe-
males and the young. The sorting of the in-
dividuals into pools have been done ac-
cording to the studies ol age/length at sex-
ual maturity (Bloch et al., 1993b, De-
sportes et al, 1993; Martin and Rothery,
1993) and was done because the concentra-
tions of pollutants do vary with age and sex,
and a large number of individuals thus
could be analysed in pools at reduced costs
The overall mean of the pod muscle mer-
cury concentration was 1,94 mg/kg in the
period 1997 to 2002, where the majority of
the samples were taken in 1997 (Dam and
Bloch, 2000). Samples front in all 100 indi-
viduals, from the Tórshavn, Nov’97 and
Leynar Dec’97 pods were analysed individ-
ually, for mercury as well as for persistent
organic pollutants (Dam, 2001).
A comparison of mercury in muscle, kid-
ney and liver is given in Table 16 where it is
seen that the most marked increase in mer-
cury with size is taking place in the liver tis-
sue. To a certain but for females limited ex-
tent, body length is correlated to age (Bloch
et ai, 1993b) and several analyses have
shown that mercury is positively correlated
to length (as in Fig. 16). Explicitly, mercury
and age have indeed been shown to be pos-
itively correlated in studies by Caurant et
al. (1994). In the Table 16, it is seen that a
ratio of 19 is found for the mercury liver
concentration in an 8 skinn (see below) fe-
male to the median mercury liver concen-
tration of the entire sample, whereas the
kidney mercury concentration in this same
individual is only two times the sample me-
dian. The relatively low median liver mer-
cury of 12 mg/kg also indicate that there are
many individuals whose liver mercury con-
centration is low and comparable to the
muscle mercury concentration, which is
overall lower than in kidney and especially
compared to what may be found in the liv-