METHODS 



Sample Collection 



Samples of blubber, liver and kidney, collected from a subset (n = 20) of 

 about 350 bottlenose dolphins that were beached along the Gulf of Mexico from 

 February to June, 1990 (Figure 1, Table 1), were provided to us by Larry 

 Hansen (Southeast Fisheries Science Onter, NMFS, NOAA). The samples were 

 placed in aluminum foil, frozen and shipped to Northwest Fisheries Science 

 Center. 



The 20 bottlenose dolphins analyzed in tiiis study were stranded over a 

 wide area in the Gulf of Mexico (Figure 1, Table 1). Two do^hins were 

 stranded in areas south of Galveston, Texas, 10 in the immediate vicinity of 

 Galveston and 2 in areas north of GalvestoiL Additionally, one dolphin was 

 stranded at a site in Lousiana, one in Mississippi, one in Alabama, and three 

 animals in the Florida area. Ten of flie dolphins were males and 10 females; each 

 sex was represented by various ages. The age of 8 dolphins was estimated from 

 sectioned teeth, and the age of the other 12 do^hins was estimated using a 

 length/age chart (Table 1). Eight of the animals were immamre (< 1 year, 3 

 females and 5 males), six animals were maturing (1-8 years; 3 females and 3 

 males) and six animals were mature (> 8 years; 4 females and 2 males) [Table 1]. 

 One dolphin was alive (condition 1) when fi«t sQ-anded. The others were in 

 various stages of decomposition: eight animals had been dead < 24 hours 

 (condition 2) and 1 1 dolphins were moderately decomposed being dead from one 

 day to one week (condition 3). 



Analyses for Metals 



The analytical methodologies and quality assurance procedures used here 

 were modified from those used in NOAA's National Benthic Surveillance Project 

 (NBSP). Thawed tissue (1.0-1.8 g) of liver and kidney were digested with 10 mL 

 of concentrated ultrapure nitric acid for 2 hours at room temperature in a sealed 

 Teflon bomb. Then the bomb was heated in a microwave oven at 650 watts for 6 

 min. The digestate was further treated to destroy organic matter by digestion 

 with 4 mL hydrogen peroxide and again heated in the microwave oven. The 



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