Freshwater food chain

Ferard, J.F., J.M. Jouany, R. Truhaut, and P. Vasseur. 1983. Accumulation of cadmium in a freshwater food chain experimental model. Ecotoxicol. Environ. Safety 7 43-52. 

Diet is the most important route of copper accumulation in aquatic animals, and food choice influences body loadings of copper. For example, whole-body copper concentrations in aquatic insects from copper-contaminated rivers are highest in detritovores (as high as 102 mg/kg DW), followed by predators (54 mg/kg DW) and omnivores (43 mg/kg DW Cain et al. 1992). Little or no biomagnification of copper is evident in freshwater food chains (Stokes 1979). 

Kuroiwa, T., Ohki, A., Naka, K. and Maeda, S. (1994) Biomethylation and biotransformation of arsenic in a freshwater food chain green alga (Chlorella vulgaris) — shrimp (Neocaridina denticulata) — Killifish (Oryzias latipes). Appl. Organomet. Chem., 8, 325-333. 

TABLE 4. Arsenic accumulation and metabolism in three-step freshwater food chain ... 

Table 5-7. Comparison of the Biomagnification of Methylmercury and Inorganic Mercury in a Freshwater Food Chain (Little Rock Lake)...

Chemical structures of the arsenic compounds in marine organisms have been confirmed in many cases, but very few chemical species of arsenic in freshwater organisms have been found. Arsenic transformation via the freshwater food chain has rarely been reported. This chapter focuses on the toxicity of arsenicals and the biotransformation of arsenic in the freshwater organisms. 

Biotransformation of Arsenic via the Experimental Freshwater Food Chain... 

TABLE 5. Arsenic accumulation and metabolism in three-step freshwater food chain (phytoplankton Nostoc sp - shrimp N. denticulata carp C. carpio) [51]... 

Recently Maeda and his co-workers reported experimental results on the transformation of arsenic via some experimental freshwater food chains [48-52]. In a three-step freshwater food chain (phytoplankton Nostocm sp. —shrimp N. denticulata —carp C. carpio), arsenic accumulation from food decreased one order of magnitude and the biomethylation ratio of the arsenic increased successively with elevation in the trophic level (see TABLE 5). 

The results obtained from marine and from freshwater organisms closely resemble each other in that herbivorous and carnivorous organisms accumulated predominantly dimethylarsenic and trimethylarsenic, respectively. The experimental results from freshwater food chains showed that arsenic concentration in organisms decreases with elevation in the trophic level the results from the marine food chain were the same [46]. 

---