Terrestrial Mammals

The highest total PCB concentrations recorded in terrestrial mammalian wildlife occurred in fat and liver tissues of species collected 

Populations of bats in Europe have been declining, and PCBs together with pesticides and wood preservatives are the suspected main causes of the decline. Three species of bats collected in Spain during 1988-90 contained only a few dominant PCB congeners PCBs 138, 153, and 180 accounted for about 80% of the total PCB burden in whole bats. But the most abundant PCB congeners in brain and liver of European otters (Lutra lutra) were in the descending order of PCBs 163, 153, 138, and 170, each constituting at least 10% of the total PCB burden. 

In humans, total PCB concentrations in maternal milk were elevated ( 1.1 mg/kg milk fat) in 4 of 122 cases in the New Bedford Harbor vicinity, Massachusetts. At least one female was occupationally exposed, as judged by the congener profile and history. PCB exposures from fish consumption were likely, but not from residence adjacent to a PCB-contaminated site. In all 4 cases, their newborns were full-term and healthy. 

Zebra mussels Dreissena polymorpha) accumulated PCB 77 from their diet and from the surrounding lake sediments. An uptake rate of PCB 77 by zebra mussels followed the descending order of sediment, food, and water. Tissue concentrations in mussels peaked after 10-14 days at 3.4-3.7 mg PCB 77/kg FW soft parts equilibrium levels of PCB 77 were near l.Omg/kg FW. Zebra mussels are more efficient accumulators of PCBs than other bivalve molluscs to which they are attached accordingly, high densities of zebra mussels probably influence contaminant dynamics. A freshwater crustacean Mysis relicta) plays an important role in the transfer of PCBs from sediments into 

In that study, muscle of treated quails had increased loadings of congeners chlorinated in the 2,4,5 position (such as PCBs 138,153,170, and 180), and these are comparatively toxic and resistant to metabolic degradation. More research is needed on variables known to modify PCB uptake, retention, translocation, and toxicity. 

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AVP plays a central role in water homeostasis of terrestrial mammals, leading to water conservation by the kidney. OT is primarily involved in milk ejection, parturition and in sexual and maternal behaviour. Both hormones are pqDtides secreted by the neurohypophysis, and both act also as neurotransmitters in the central nervous system (CNS). The major hormonal targets for AVP are the renal tubules and vascular myocytes. The hormonal targets for OT are the myoepithelial cells... 

Far less is known about excretion by terrestrial insects than by terrestrial mammals. Metabolism can take place in the midgut and fat body. Excretion can occur via the malpighian tubules. 

Thompson DR. 1996. Mercury in birds and terrestrial mammals. In Beyer WN, Heinz GH, Redmon-Norwood AW, editors. Environmental contaminants in wildlife interpreting tissue concentrations. Boca Raton (FL) Lewis Publishers. 

Marine mammals usually contain less than 44 mg Cu/kg DW in all tissues except livers. Copper in livers seldom exceeds 116 mg/kg DW except in polar bears (146 mg/kg DW), and manatees, Trichechus manatus, (1200 mg/kg DW) from a copper-contaminated site (Table 3.3). Maximum copper concentrations in terrestrial mammals from all collection sites are usually less than 29 mg/kg DW in all tissues except kidneys (108 mg/kg DW) and livers (1078 mg/kg DW Table 3.3). 

Hill, E.P. and D.M. Dent. 1985. Mirex residues in seven groups of aquatic and terrestrial mammals. Arch. Environ. Contam. Toxicol. 14 7-12. 

Marine mammals (4 species blubber) vs. terrestrial mammals (human, dog, cat adipose or intestinal fat) ... 

TERRESTRIAL MAMMALS Cattle, Bos sp. Nevada, 1973, grazing for 3 years in area contaminated in 1957 with transuranic radionuclides 241 Am ... 

Many terrestrial mammals self-groom when they encounter odors of opposite-sex conspecifics (Steiner 1973 Brockie 1976 Wiepkema 1979 Harriman and Thiessen 1985 Thiessen and Harriman 1986 Witt, Carter, Carlstead and Read 1988 ... 

Figure 8.7 Relationship between bone collagen carbon isotope ratio and latitude for modern carnivorous terrestrial mammals. The regression equation is given as <513C = -0.20 ( 0.03) x latitude - 9.7 ( 1.0), with r2 = 0.75. Reproduced from Kelly (2000 7) by permission of the National Research Council Canada Research Press.

Mirex was also detected in the muscle and liver tissues of seven species of aquatic and terrestrial mammals collected in areas of Alabama and Georgia that had been repeatedly treated with mirex to suppress fire ant populations from March 1973 through July 1976. At 6 months post-treatment, skunk and opossum muscle tissue contained the highest mean mirex concentrations of 3.50 and 1.51 pg/g (ppm), respectively (Hill and Dent 1985). Two years post-treatment, muscle residues declined in all species except the mink, which increased from 0.14 pg/g at 6 months post- treatment to a mean muscle residue of 0.28 pg/g at 1 year post-treatment and 0.53 pg/g at 2 years post-treatment. 

It is apparent that the aquatic echinoderm and terrestrial mammal deal with a chemical probe by very different metabolic pathways. The exclusive formation of oxidized ((T-demethylated) product in the mouse may partly reflect the animal s highly oxidizing environment, while the relatively anoxic marine environment is represented in the observed reduced metabolites of the sea urchin. 

In the present compilation of the distribution and pharmacokinetic data of a dozen xenobiotics studied in the dogfish shark, this species yielded excellent data consistent with what we know from similar studies on terrestrial mammals. The data from the shark occasionaly provided information not available in other animals. Major transport parameters in this fish were shown to be similar to those found in mammals. This aquatic organism handles lipid-soluble pollutants by sequestering them in its fatty liver. Together with a previous summary (23) we have now studied about three dozen xenobiotics in this species. Because of its ease of handling, low cost, abundance, predictive value of transport mechanisms, and well-developed pharmacokinetics, the dogfish shark is an ideal fish species to use as a model to study aquatic pollutants. 

Unlike most terrestrial mammals, beavers maintain territories along a line following watercourses. Both species, the Eurasian beaver, C. fiber, and the North American beaver, C. canadensis, dredge up mud from the bottom of their home pond, carry it on land, deposit it, and apply a scent mark on top of this mud... 

Crab hepatopancreas English sole (Pleuronectes vetulus)-, liver Rainy River, Ontario 1988 total PCBs Mill effluent, water vs. suspended solids Fish, two species upstream vs. downstream Marine mammals (4 species blubber) vs. terrestrial mammals (human, dog, cat adipose or intestinal fat) Total PCBs Di-ortho planars PCB 128 PCB 138... 

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