Biotransfer of metals to the insect Neochetina eichhornae via aquatic plants

Abstract

Trace elements are ubiquitously present in the environment occurring naturally in soil and water. However, the present day concern is their increase in the environment due to rapid industrialization. An attempt was made to determine the bioaccumulation of trace elements transferred from the aquatic medium to aquatic plants placed in the experimental medium and subsequently biomagnified through the food chain in insects feeding on the leaves. The biosystem under study was the aquatic plant Eichhornia crassipes (Mart) Solms and their specific feeders Neochetina eichhornae (Warner). The plants exposed to known concentrations of Cd, Zn, Hg, and Mn for one week were fed to the insects and the concentration of metal ions in various parts of the plants and insects was determined by atomic absorption spectroscopy and ICPAES. The rates of uptake of the various metal ions varied, depending upon metal solubility and their affinities to the biosystems. Bioaccummulation in the roots was highest compared to the aerial parts of the plant. This investigation revealed the biotransfer of metals via a simple food chain model which consisted of two trophic levels, from contaminated waters to the insects via the aquatic plants. © 1992 Springer-Verlag New York Inc.