Do Cd, Cu, Ni, Pb, and Zn biomagnify in aquatic ecosystems?

Trophic transfer (biotransference—Dallinger et al. 1987) results from passage of a contaminant through food chains as a result of uptake only from water (bioconcentration), only from diet (dietary accumulation), or from a combination of these (bioaccumulation) (Biddinger and Gloss 1984; Davis and Foster 1958; Macek et al. 1979; Suedel et al. 1994). Trophic transfer factors (TTFs) are analogous to bioaccumulation (accumulation) factors, the original terms used to describe steady-state tissue residues in an organism resulting from both water and dietary uptake pathways (Boroughs et al. 1957). TTFs are the same as biomagnification factors and also meet the definition of biomagnification when TTFs exceeding 1.0 are observed through three or more trophic levels as a result of at least two trophic transfers (Biddinger and Gloss 1984). Most investigators have assumed TTFs result mainly from dietary accumulation (Baptist and Lewis 1967; Mathews and Fisher 2008; Reinfelder et al. 1998), although it is not possible to distinguish aqueous from dietary uptake in field studies. Moreover, the relative importance of the diet and aqueous uptake pathways is context-dependent, varying with exposure duration, metal bioavailability, and the species and their prey. Application of the aquatic TTF concept, as currently understood, may have first been proposed by Baptist and Lewis (1967), and the term had been widely adopted by the early 1990s (Baudin and Nucho 1992; Dillon et al. 1995; Garnier-Laplace et al. 1997; Suedel et al. 1994).