MODELING BIOCONCENTRATION AND BIOACCUMULATION OF DIOXINS IN BIVALVES AND FISHES OF THE LAGOON OF VENICE

摘要

Researches concerning the Lagoon of Venice are spending an increasing attention to the problem of the presence of micro-pollutants in sediment, water and biota. Recent investigations found evidence of high concentration of dioxins in some industrial channels and suggested to the public Authority to monitor this situation in about a hundred sites in the whole Lagoon. The paper estimates, through the use of models, the propagation of dioxin-like substances from sediment to edible organisms. Measured dioxins' concentrations in sediments and in water were used to calibrate partitioning models between solid and dissolved phases in the water column, whereas measured concentrations in edible organisms were used to calibrate bioaccumulation. The estimation of concentrations in organisms was obtained by coupling a toxic substance food web model with a trophic network model previously set up for a shallow water area of the Lagoon. Results showed a good agreement with experimental values for a filter feeding edible bivalve widely caught in the Lagoon (Tapes philippinarum) and for the detritivorous fish Zosterissessor ophiocephalus. This model represents a tool to assess contamination levels in organisms, which completes direct measurements; the model is going to be extended to other organic and inorganic contaminants becoming a useful tool for management practices.