Wildlife marine mammals

Law RJ. 1996. Metals in marine mammals. In Beyer WN, Heinz GH, Redmon-Norwood AW, editors. Environmental contaminants in wildlife interpreting tissue concentrations. Boca Raton (FL) CRC Press, p. 357-376. 

Hellou, J. 1996. Polycyclic aromatic hydrocarbons in marine mammals, finfish, and molluscs. Pages 229-250 in W.N. Beyer, G.H. Heinz, and A.W. Redmon-Norwood (eds.). Environmental Contaminants in Wildlife Interpreting Tissue Concentrations. CRC Press, Boca Raton, FL. 

From the human perspective, HABs are problematic because they cause (1) risks to human health, (2) loss of natural or cultured seafood resources, (3) impairment of tourism and recreational activities, and (4) damage to noncommercial marine resources and wildlife. Exposure pathways include (1) consumption of toxic shellfish that have accumulated phytoplankton toxins filtered from the water, (2) consumption of tropical fish that have accumulated phytoplankton toxins (ciguatera), (3) inhalation of aerosolized toxins ejected from the sea surface, and (4) skin contact resulting in irritations due to allergy-like reactions. Harmful health effects from acute exposures have been relatively well studied. Less well known are the health effects resulting from chronic exposures to low toxin levels. This is of particular concern with regards to marine mammals and seabirds. 

The government has been measuring PCB, HCB, DDT, chlordane, heptachlor epoxide and dieldrin since 1998 to identify their effects on wildlife as part of the Environmental Survey on Endocrine Disruptors. The specimens taken include land animals such as raccoons, bears, monkeys and frog, and marine mammals such as seals and whales, in addition to domestic birds and birds of prey. A relatively high concentration of POPs was seen in birds of prey and Phalacrocorax carbo. Eggs of mountain hawk eagles were also found to have a higher concentration of PCB, DDT, heptachlor epoxide, chlordane and dieldrin than other wildlife specimens... 

This increased exposure has been demonstrated by serum CDD levels, which are found to be several times higher in people who regularly eat fish as compared to those who occasionally or never eat fish (Anderson et al. 1998 Svensson et al. 1991) (see Sections 5.5 and 5.9). In addition, this same situation also applied for consumption of wildlife, specifically marine mammals (Ayotte et al. 1997 Dewailly et al. 1992). Similar dietary situations exist for children of subsistence hunters that tend to consume tissues of marine mammals and children of subsistence farmers that consume beef, milk and other dairy products from their own farm raised animals. In the case of subsistence fishers, subsistence hunters, and subsistence farmers, all three populations share one problem, that the source of their fish, meat, and/or milk and other dairy products, is typically restricted to a localized area, and if these food sources are contaminated with CDDs, adults and children in these populations will be exposed to higher levels of CDDs than members of the general population (see Section 5.7 for additional details on these populations at risk). 

Data on PCDD and PCDF concentrations in wildlife are scarce and mainly available for aquatic species. OctaCDD, 2,3,7,8-tetraCDD and 1,2,3,7,8-penta-CDD are the most abundant PCDD congeners in marine mammals and 2,3,7,8-tetraCDF and 2,3,4,7,8-pentaCDF the most abundant PCDFs.36 Hexa- and heptachlorinated dioxin and furan concentrations are usually very low in marine mammals and may point to relatively high metabolic and elimination rates.37... 

Apart from the descriptive DBTK models for vertebrates, PBTK approaches have been developed with numerous human and rodent PBTK models and, to a limited extent, within the ecotoxicology arena with examples in fish (Nichols et al. 1990 Law et al. 1991) and marine mammals (Hickie et al. 1999). There is also an increasing interest in using PBTK modeling for extrapolation to wildlife species (National Health and Environmental Effect Research 2005), and for this purpose, candidate species have been identified and include the mallard duck, Japanese quail, pheasant, and chicken. There is also growing research interest to develop models for other mammalian wildlife species and amphibians to address specific research and risk assessment needs. 

Effects have also been observed on the environment. Rachel Carson s Silent Spring in the 1960s drew attention to effects on wildlife. Our Stolen Future (Colbom et al. 1996) created an interest in disruption of the endocrine system by chemicals, even in animals. Many cases of effects on natural animal populations can now be inferred from laboratory experiments, although confirmation in the environment is extremely difficult. For instance, organochlorinc concentrations in adult male bottlenose dolphins are approaching the levels associated with adverse effects found in marine mammals (Carballo et al. 2008), and exposures of tadpoles to a mixture of nine pesticides at environmentally occurring levels lead to developmental effects in most frogs, while none were observed when the pesticides were applied one at a time (Hayes et al. 2006). 

The two prime sources of statistics relating to fats and oils are The Fats and Oils Situation of the Department of Agriculture and Canned Fish and By-Products of the Fish and Wildlife Service. The latter gives production of oils obtained from fish and marine mammals together with such by-products as kelp products, agar, and glue. The Fats and Oils Situation is rich in comment, news, and statistics. 

Polychlorinated biphenyls (PCBs) and dioxins are two groups of toxic organic contaminants that are widespread throughout the ecosystem as a consequence of its persistence and potential for bioaccumulation in the environment. These occur in water, air, soil, sediment, and biota in different areas around the world. In general, water birds and marine mammals have accumulated the dioxins and dioxin-Uke PCBs with much higher concentrations than humans, implying higher risk from exposure to wildlife. ... 

Environmental impact It is undeniable that the environmental impact of the disaster was catastrophic. The oil spiU lasted for about 87 days before it was stopped. An independent analysis indicated that the total spilled oil was around 185 million gallons plus another 33.8 million gallons that were captured by BP. As a result, hundreds of miles of shoreline were oiled and large areas of the sea were closed to fishermen. Moreover, wildlife was affected by the oil spill thousands of birds, fish, turtles and marine mammals were killed. 

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