Comparison of organochlorine contaminants among sea otter (Enhydra lutris) populations in California and Alaska

Abstract

Abstract-Organochlorine pesticides, polychlorinated biphenyls (PCBs) including non-ortho PCBs, polychlorinated dibenzo-pdioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) were measured in sea otter liver tissue from California, southeast Alaska, and the western Aleutian archipelago collected between 1988 and 1992. Average total dichlorodiphenyltrichloroethane concentrations for California otters (850 g/kg wet weight) were over 20 times higher than in Aleutian otters (40 g/kg) and over 800 times higher than otters from southeast Alaska (1 g/kg). Levels for total PCBs in Aleutian otters (310 g/kg) were 1.7 times higher than levels in California otters (190 g/kg) and 38 times higher than otters from southeast Alaska (8 g/kg). Levels for PCDD and PCDF were extremely low in all otter populations. Levels of PCBs in Aleutian and Californian otters are abnormally high when compared with southeast Alaskan otters. The source of PCBs to the Aleutian Islands remains unclear and vital to understanding the potential impacts to sea otters.

Profiles of polychlorinated biphenyl congeners, organochlorine pesticides, and butyltins in southern sea otters and their prey

“…Both TCPME and TCPMOH were detected in several prey species of sea otters. An earlier study has reported the occurrence of 4 ng TCPMOH/g liver in sea otters [17]. Lipid‐normalized concentrations of TCPMOH in sea otter livers (100 ng/g) were approximately ninefold greater than concentrations found in prey items (11 ng/g), suggesting biomagnification of this compound in the sea otter food chain.…”

“…The estimates of TEQs in sea otters and shellfish prey may be considered conservative, because they only represent a few mono‐ and non‐ ortho congeners and do not consider di‐ ortho PCBs, which are present at considerable concentrations in sea otters. In addition, other dioxin‐like compounds, such as polychlorinated dibenzo‐ p ‐dioxins and dibenzofurans [17], may add to the existing burdens of TEQs in sea otters and their prey. Furthermore, mammalian TEFs were derived based on studies with terrestrial mammals.…”

Elemental and Organochlorine Residues in Bald Eagles From Adak Island, Alaska

“…Many environmental contaminants, including heavy metals and organochlorines, are associated with industrial emissions and large-scale agriculture, yet studies have demonstrated elevated levels of some contaminants far from known or suspected sources (Bacon et al, 1999;Bard, 1999). Top-level predators, such as bald eagles (Haliaeetus leucocephalus), are believed to be especially vulnerable to many contaminants and can be used as sentinel species for contaminated areas (Welch, 1994;Holl and Cairns, 1995).…”

Toxaphene and other persistent organochlorine pesticides in three species of albatrosses from the north and south Pacific Ocean

“…Despite recent use of DDT in China and southeast Asia compared with North America [55] and evidence for trans‐ Pacific transportation of DDT [48], Laysan albatross do not show elevated concentrations of DDT‐related compounds, including TCPMe, compared with blackfooted albatross. The DDT contamination of marine food webs along the west coast of North America remains relatively high [47,56] and, although data for comparable species are limited, is higher than in marine food webs from the Asian coast of the Pacific [2,57]. The TCPMe/OH concentrations also appear to be greater in North American waters than in Asia [57,58].…”