Organochlorine Pesticides, Polychlorinated Biphenyls, and Butyltin Compounds in Blubber and Livers of Stranded California Sea Lions, Elephant Seals, and Harbor Seals from Coastal California, USA

Abstract

Concentrations of polychlorinated biphenyls (PCBs), DDTs (p,p'-DDE, p,p'-DDD, p,p'-DDT), chlordanes (CHLs; cis-chlordane, cis-nonachlor, trans-nonachlor, and oxychlordane), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), tris(4-chlorophenyl)methane (TCPMe), tris(4-chlorophenyl)methanol (TCPMOH), and mono- (MBT), di-(DBT), and tri-butyltin (TBT) were determined in blubber and livers of 15 California sea lions (Zalophus californianus), 6 northern elephant seals (Mirounga augustirostris), and 10 harbor seals (Phoca vitulina) found stranded along the coasts of California, USA, during 1991-1997. Among the organochlorines analyzed, DDTs were predominant, followed in decreasing order by PCBs, CHLs, TCPMe, TCPMOH, HCHs, and HCB. The greatest concentrations of organochlorines were found in California sea lions. The highest DDT and PCB concentrations found in the blubber of California sea lions were 2,900 and 1,300 microg/g, lipid weight, respectively. Concentrations of TCPMe and TCPMOH in California sea lions were correlated significantly with DDT concentrations. Concentration ratios of various organochlorines in harbor seal livers were different from those in California sea lions and elephant seals, which suggested that the sources of exposure of harbor seals to organochlorines were different from those in the other two species. Concentrations of butyltin compounds in livers of pinniped species ranged from 2 to 99 ng/g, wet weight, which were less than those observed in cetaceans and in California sea otters.

Use of DDTs and PCBs as chemical tracers in assessing the foraging locations and habits of northern elephant seals from Guadalupe Island (Mexico)

“…The second and third most abundant contaminants were PCBs, and CHLs, which is consistent with the results found in most recent studies of pinnipeds affected by the California Current, such as the NES, California sea lions (Zalophus californianus), and harbor seals (Blasius & Goodmanlowe, 2008;Kajiwara et al, 2001;Peterson et al, 2015).…”

“…Known females in this study did exhibit higher variation in contaminant concentrations compared to males. High variability of tDDT concentrations was observed among individuals, as was also observed in a study by Kajiwara et al (2001;Table 2). Despite failing to find significant differences in the mean concentrations of OCs between males and females, partially due to the small sample size, there was considerable difference in the coefficients of variation between sexes, showing greater variability in the concentrations of tDDTs and tPCBs in females.…”

Apex marine predators and ocean health: Proactive screening of halogenated organic contaminants reveals ecosystem indicator species

“…Following its discovery in Puget Sound and Baltic Sea seals around 1990 (Walker et al, 1989;Zook et al, 1992), 4,4',4''-TCPM was determined to be an impurity from the technical preparation of pesticides such as DDT (Buser, 1995) and dicofol (de Boer, 1997). TCPM and its derivative, tris(4chlorophenyl)methanol (TCPMOH), were measured in marine mammals from North America and Asia in the early 2000s, and were determined to have high biomagnification potential (Kajiwara, K. Kannan, M. Muraoka, M., 2001;Kannan et al, 2004;Minh et al, 2000;Watanabe et al, 2000). Although previously found to be one to three orders of magnitude greater in sea lions off the Northern and Central California coast compared to species from other locations (Kajiwara, K. Kannan, M. Muraoka, M., 2001;Kannan et al, 2004), TCPM and TCPMOH appear to have lost recognition as a pervasive contaminant in the North Pacific over the past decade.…”

Effects of Age, Adipose Percent, and Reproduction on PCB Concentrations and Profiles in an Extreme Fasting North Pacific Marine Mammal

“…While on land for breeding/lactation or molting, elephant seals cease feeding and go through extreme reductions in adipose stores, losing up to 40% of their body mass [41]. Previous studies of PCB concentrations in stranded northern elephant seals along the California coast [42], [43] demonstrated the capacity for PCBs in elephant seals to reach concentrations of toxicological concern [44]; however, we still do not know how concentrations fluctuate in healthy, wild animals throughout the year in relation to the naturally occurring extremes of adipose percent. The unique life history strategy of elephant seals, with separate fasting periods for breeding/lactation and molting, can allow us to disentangle the effects of fluctuating adipose percent with the effect of maternal offloading of contaminants.…”