Page 2 - Dolphin_Tuna_Shark_1996

20 K. Kannan et al.

Bottlenose dolphins

\
S. Maria di Leuca
(Blue shark)
Egadi Islands (Bluefin tuna)

Fig. 1. Map of Italy showing sampling locations of
bottlenose dolphins, bluefin tuna, and blue sharks

final hold time. Injector and detector temperatures were held at 200
stranded along the Italian coast of the Adriatic Sea (Figure 1) in 1992.
Only blubber was available from an another male Tursiops. All the and 270°C, respectively. The flame photometer was operated, using a
animals were found dead and the carcasses were at different stages of hydrogen-air-nitrogen flame and was equipped with a 610 nm bandpass
decomposition. The length of dolphins were between 300 and 320 cm. filter that is selective for tin-containing compounds.
The age of the animals was not determined; however, based on length Butyltin trichloride, dibutyltin dichloride and tributyltin chloride of
estimates, the dolphins analyzed are considered to be adults of greater known amounts (0.1 b~g) spiked into the muscle of cod (Gadus morhua),
caught off the Pacific Ocean, containing butyltin concentrations below
than I0 yrs old (length of bottlenose dolphin at birth is 115 cm and
the limit of detection, were concurrently run with samples through the
reaches 250 cm at about 10 yrs).
Blue sharks (Prionace glauca) were collected in S. Maria di Leuca whole analytical procedure and the propylated mixture was used as an
(Figure 1), along the east coast of Italy during 1992. Subcutaneous fat external standard. Only freshly derivatized external standards prepared
(near the caudal fin), liver, and kidney were excised and total length along with samples were used to estimate concentrations. Concentra-
and body weight were recorded. Based on length estimates, it is as- tions were quantified by comparing peak heights of butyltin compounds
sumed that all the sharks analyzed are immature. in samples with those in the external standards. A procedural blank
was also run simultaneously with every batch of four samples to check
Bluefin tuna (Thunnus thynnus thynnus) were collected from Egadi
Islands near Sicily (Figure 1 ) in May 1993. Muscle (mid-dorsal region) for interfering compounds and to correct sample values, if necessary.
and liver were dissected using a pre-cleaned scalpel and wrapped in Monobutyltin was found at trace levels in reagent blanks (ca 1-5 ng),
a clean aluminum foil. Both shark and tuna were collected by netting. which may be from the Grignard reagent or from PVC containers used
All the samples were preserved in dry ice immediately after collection, for the storage of chemicals or reagents. The values obtained for MBT
brought to laboratory and frozen at -20°C until analysis. Samples in samples were, therefore, corrected for reagent blank concentrations.
Detection limits of butyltins in samples were assigned twice the values
were analyzed within a month after collection to avoid possible effects
of procedural blanks. Detection limits of MBT, DBT, and TBT in
of long-term storage on butyltin speciation.
tissues were 5.0, 1.0, and 0.50 ng/g wet wt, respectively. The recoveries
of monobutyltin trichloride, dibutyltin dichloride and tributyltin chlo-
ride dissolved in hexane, spiked into the muscle of cod and passed
Chemical Analysis
through the whole analytical procedure were, 85 _+ 19, 106 + 11 and
93 + 5%, respectively. The recoveries of matrix spiked compounds
The analytical methods used for the determination of MBT, DBT and
were calculated based on the freshly propylated external standard mix-
TBT, have been described (Kannan et al. 1995a). Briefly, acidified
ture. In addition, hexyl TBT was added as an internal standard, and
tissue samples were extracted with 0.1% tropolone-acetone, transferred
its recovery through the analytical procedure was 88 -+ 12%. The
to 0.1% tropolone-benzene and eluted through a NazSO4 packed glass
concentrations of butyltin compounds are reported as ng of correspond-
column to remove water. An aliquot of the concentrated extract was
ing ion/g on a wet weight basis.
used to determine fat content gravimetrically. The concentrated extract
was propylated with n-propyl magnesium bromide as the Grignard
reagent (ca. 2 mol/L in tetrahydrofuran solution, Tokyo Kasei Kogyo
Results and Discussion
Co. Ltd., Japan). Excess Grignard reagent was destroyed with 1N
H2SO4 and the derivatized extract was passed through a 20 g Florisil ®
packed dry column to remove lipids and final purification by passage
Bottlenose Dolphin
through a 6 g Florisil ® packed wet column.
Sample extracts were analyzed by capillary gas chromatography
Concentrations of total butyltin (BTs; MBT + DBT + TBT) in
with flame photometric detection (GC-FPD). Chromatographic separa-
the blubber and liver were in the ranges of 48-320 ng/g wet
tion was performed on a Hewlett-Packard 5890 series II gas chromato-
wt (mean: 159 ng/g) and 1,200-2,200 ng/g wet wt (mean: 1,700
graph with a 30 m × 0.25 mm (i.d.) DB-1 capillary column coated at
ng/g), respectively (Table 1). On average, hepatic BT concentra-
0.25 txm film thickness. The column oven temperature was pro-
tions were about 10-fold higher than those observed in the
grammed from 80°C (l-rain hold) to 160°C at a rate of 15°C/rain and
blubber. Analysis of finless porpoise (Neophocaena phocae-
then at a rate of 5°C/rain to a final temperature of 260°C with a 5-rain