Terrestrial animals bioaccumulation

Food Chain Bioaccumulation. There is information that barium bioconcentrates in certain plants and aquatic organisms (Bowen 1966 Schroeder 1970). However, the extent to which plants bioconcentrate barium from soil or to which uptake occurs in terrestrial animals is not well characterized. Further studies on the bioconcentration of barium by plants and terrestrial animals and on the biomagnification of barium in terrestrial and aquatic food chains would be useful to better characterize the environmental fate of barium and define the importance of food chain accumulation as a source of human exposure. 

Bioaccumulation is accumulation of contaminants in tissues resulting from exposure to all possible sources such as water and diet. Although it is beyond the scope of this chapter, information on the bioaccumulation of plasticizers in terrestrial animals is limited, but trophic transfers are thought to be insignificant because of extensive biotransformations. 

In contrast, fish and fish products can be highly burdened with mercury, especially methylmercury. The highest concentrations are found both in marine and freshwater fish at the highest trophic levels of the aquatic food chain, caused by bioaccumulation [4-6] (see Sec. 2.1). The mean mercury concentration in the edible parts of these problem fishes is approximately 1 mg/kg, but peak values even of 10 mg/kg have been reported [16,17]. Shellfish also accumulate methylmercury to a high extent. For instance, the weekly consumption of 200 g of fish containing only 0.5 mg mercury/kg results in the intake of 100 p,g mercury per week [2]. This amounts to one-half of the PTWI (provisional tolerable weekly intake), as recommended by the World Health Organization (WHO) [4,18]. The feeding of animals like chickens with fish meal may raise the mercury burden of terrestrial animal foodstuffs too. 

Food Chain Bioaccumulation. Endosulfan is bioconcentrated by aquatic organisms (Ernst 1977 Novak and Ahmad 1989 NRCC 1975 Roberts 1972 Schimmel et al. 1977) but not by plants or animals (ERA 1982a). The compound is metabolized by terrestrial (Coleman and Dolinger 1982 El Beit et al. 1981c Martens 1977 NRCC 1975) and aquatic organisms (Cotham and Bidleman 1989), and it does not biomagnify to any great extent in terrestrial or aquatic food chains (HSDB 1999). No additional information on the bioaccumulation of endosulfan is needed at this time. 

Mercury (Hg) contamination is widespread in water, in surficial soils and sediments, and in the tissues of plants and animals in ecosystems around the globe. Once deposited to terrestrial and aquatic ecosystems, some inoiganic mercury is transformed into methylmercury (MeHg), a highly toxic compoimd that bioaccumulates efficiently in food webs (Wiener et al. 2003). As a result of the toxicity of MeHg to wildlife and humans, many nations are interested in reducing environmental mercury contamination and associated biotic exposure (UNEP 2002). 

Food Chain Bioaccumulation. Lead is bioaccumulated by terrestrial and aquatic plants and animals (Eisler 1988). However, lead is not biomagnified in terrestrial or aquatic food chains (Eisler 1988). No additional information is needed. 

Terrestrial fauna, such as birds, mammals, or domestic animals. Effects are heavy metals accumulation followed by possible disturbance of physiological and biochemical reactions and metabolisms. Bioaccumulation of Cd, Hg and Cu in the food web is the most important concern. 

Food Chain Bioaccumulation. Simple cyanide compounds do not bioconcentrate in fish (ASTER 1994 Callahan et al. 1979 EPA 1985a). It would be useful to determine the bioconcentration potential for cyanide in fish from water dosed with less toxic and water-soluble cyanide complexes. There is no indication of biomagnification of cyanides in aquatic and terrestrial food chains. Because of the high toxicity of cyanides at high doses and rapid metabolism at low doses, biomagnification of cyanide in animals seems unlikely. 

The modified terrestrial-aquatic model ecosystem described here has been found to be a useful tool in studying the environmental fate of drugs and related residues present in animal excreta used as manure. The operation of the ecosystem is relatively simple and yet it allows one to study the complex metabolic transformations of a drug or related residues in its various components. Especially interesting is the study of the degradation of a compound in the soil in the presence of microorganisms found in the animal excreta. This information is important since it eventually determines whether a compound and/ or its metabolites will bioaccumulate in the various elements of the environment. 

Food Chain Bioaccumulation. 1,2-Dibromoethane is not expected to bioconcentrate in plants, aquatic organisms, or animals, or biomagnify in terrestrial or aquatic food chains as a result of its high water solubility (NIOSH 1978 Parrish 1983). Additional information is needed on bioconcentration and biomagnification of the compound to confirm this predicted environmental behavior. 

Food Chain Bioaccumulation. Data are available that indicate that chloroform does not bioconcentrate in aquatic organisms (Barrows et al. 1980 Veith et al. 1980) however, data are lacking for plants and other animals (e.g., vacuolar plants, shellfish, or macroinvertebrates) as well as for the biomagnification potential of chloroform in terrestrial and aquatic food chains. Additional information on bioconcentration and biomagnification could be useful in establishing the significance of food chain bioaccumulation as a route of human exposure. 

Food Chain Bioaccumulation. Data indicate that tetrachloroethylene has a low bioconcentration potential in aquatic organisms and animals (Barrows et al. 1990 Kawasaki 1980 Kenaga 1980 Neely et al. 1974 Veith et al. 1980). No data were located on the bioconcentration potential of this compound in plants. Research on the bioconcentration of tetrachloroethylene in plants would help in assessing the potential for exposure from ingestion of plant foodstuffs. Although biomagnification of tetrachloroethylene in terrestrial and aquatic food chains is not expected to be important because the compound is metabolized in animals, experimental data to confirm the expected behavior would be useful in evaluating the importance of food chain bioaccumulation as a source of human exposure to tetrachloroethylene. 

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