Terrestrial food chains biomagnification

More information is needed in several areas in order to establish effective criteria for the protection of sensitive species of fish and wildlife against paraquat. These include flux rates of paraquat from soil into terrestrial food chains biomagnification potential of paraquat in aquatic food chains, with special reference to plants, plant detritus, amphibians and reptiles toxicokinetics of mixtures of paraquat and other herbicides applied concomitantly and the implications of the high sensitivities of crustacean larvae and waterfowl embryos to paraquat. 

Biomagnification along terrestrial food chains is principally due to bioaccumulation from food, the principal source of most pollutants (Walker 1990b). In a few instances, the major route of uptake may be from air, from contact with contaminated surfaces, or from drinking water. The bioaccumulation factor (BAF) of a chemical is given by the following equation ... 

Gorree, M., W.L.M. Tamis, T.P. Traas, and M.A. Elbers. 1995. BIOMAG a model for biomagnification in terrestrial food chains. The case of cadmium in the Kempen, the Netherlands. Science Total Environ. 168 215-223. 

Bioconcentration and biomagnification of individual congeners in terrestrial food chains (Swackhamer and McConnell 1993)... 

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. 

Data on biomagnification of 1,4-dichlorobenzene through aquatic or terrestrial food chains were not located. 

Food Chain Bioaccumulation. Based on low log K°w values, both compounds have a low potential for bioaccumulation (Deneer et al. 1987). Based on a low experimental BCF for 1,3- DNB, bioaccumulation in aquatic organisms is not an important fate process (Deneer et al. 1987). No BCF data were located for 1,3,5-TNB. Data indicate that 1,3-DNB bioaccumulates in plants (McFarlane et al. 1987a). No studies were located regarding plant uptake of 1,3,5-TNB. Data are needed regarding the bioconcentration and biomagnification potential of both compounds in terrestrial food chains. 

Food Chain Bioaccumulation. Limited data indicate that carbon tetrachloride has a low tendency to bioconcentrate in the food chain, even though it is a lipophilic compound (Neeley et al. 1974 Pearson and McConnell 1975). The lack of bioconcentration is mainly due to the volatility of carbon tetrachloride, which facilities clearance from exposed organisms. Nevertheless, carbon tetrachloride does tend to become concentrated in fatty tissues, and further studies on the levels of carbon tetrachloride in the fat of fish would help evaluate the risk of carbon tetrachloride exposure by this pathway. No data are available on the bioconcentration in plants. Additional studies would be useful in assessing potential for human exposure from ingestion of plant foodstuff. Data are also needed on the biomagnification of the compound in the aquatic and terrestrial food chain. These data would be useful in assessing food chain bioaccumulation as a potential human exposure pathway. 

Polybrominated Diphenyl Ethers. The limited existing data indicate that PBDEs bioaccumulate in aquatic and terrestrial food chains and biomagnify in predators due to consumption of contaminated prey. More information on bioaccumulation and biomagnification of PBDE and its congeners is needed in assessing human health risks. 

Biomagnification Along Aquatic Food Chains and Food Webs Biomagnification Along Terrestrial Food Chains... 

Food Chain Bioaccumulation. No information is available regarding biomagnification within aquatic or terrestrial food chains. Additional studies would be useful in assessing potential for human exposure to chlorobenzene. 

Food Chain Bioaccumulation. Chromium does not bioconcentrate in fish (EPA 1980,1984a Fishbein 1981 Schmidt and Andren 1984). There is no indication of biomagnification of chromium along the aquatic food chain (Cary 1982). Some data indicate that chromium has a low mobility for translocation from roots to above-ground parts of plants (Cary 1982 WHO 1988). However, more data regarding the transfer ratio of chromium from soil to plants and biomagnification in terrestrial food chains would be desirable. 

Beyer WN. 1986. A reexamination of biomagnification of metals in terrestrial food chains. Environmental Toxicology and Chemistry 5 863-864. 

Diet provides the major pathway for lead exposure, and amounts in bone are indicative of estimated lead exposure and metabolism. Amounts of whole body lead and feeding habits of roadside rodents were correlated body burdens were highest in insectivores such as shrews intermediate in herbivores, and lowest in granivores. Food chain biomagnification of lead, although uncommon in terrestrial communities, may be important for carnivorous marine mammals, such as the California sea lion accumulations were highest in hard tissues, such as bone and teeth, and lowest in soft tissues, such as fat and muscle. A similar pattern was observed in the harbor seal. 

---