EMCB-ENVIS Node ENVIRONMENTAL BIOTECHNOLOGY

EMCB-ENVIS Centre
The Cd concentration in leaves was 0.1 in control and 38.4, 93.1, and 177.2 μg.g -1 (dry mass) in
Cd-treated food. The concentration in snail tissues increased with increasing Cd concentrations
in the food. The bioaccumulation factors ranged from 4.8 (control) to 2.4 (highest exposed
group), indicating a biomagnification of Cd in this food chain. The growth of the snails treated
with Cd was reduced by 17, 24, and 43% respectively, compared to the control group.
Comparison of these results with those obtained with snails exposed to similar Cd concentrations
in a vegetable flour revealed that accumulation and effects were relatively consistent,
demonstrating a comparable bioavailability of Cd in the two diets. Tests using growing H.
aspersa snails exposed to metals in flour or fresh leaves can be useful for risk assessment
purposes.
Ron van der Oost, Jonny Beyer, Nico P. E. Vermeulen. (Department of Environmental
Toxicology, OMEGAM Environmental Research Institute, PO Box 94685, 1090 GR,
Amsterdam, The Netherlands. Department of Marine Environment, RF-Rogaland Research,
Stavanger, Norway. Department of Molecular Toxicology, Vrije Universiteit, Amsterdam,
The Netherlands). Fish bioaccumulation and biomarkers in environmental risk
assessment: a review. Environmental Toxicology and Pharmacology, 13(2) (2003), 57-
149.
In this review, a wide array of bioaccumulation markers and biomarkers, used to demonstrate
exposure to and effects of environmental contaminants, has been discussed in relation to their
feasibility in environmental risk assessment (ERA). Fish bioaccumulation markers may be
applied in order to elucidate the aquatic behavior of environmental contaminants, as
bioconcentrators to identify certain substances with low water levels and to assess exposure of
aquatic organisms. Since it is virtually impossible to predict the fate of xenobiotic substances
with simple partitioning models, the complexity of bioaccumulation should be considered,
including toxicokinetics, metabolism, biota-sediment accumulation factors (BSAFs), organspecific
bioaccumulation and bound residues. Since it remains hard to accurately predict
bioaccumulation in fish, even with highly sophisticated models, analyses of tissue levels are
required. The most promising fish bioaccumulation markers are body burdens of persistent
organic pollutants, like PCBs and DDTs. Since PCDD and PCDF levels in fish tissues are very
low as compared with the sediment levels, their value as bioaccumulation markers remains
questionable. Easily biodegradable compounds, such as PAHs and chlorinated phenols, do not
tend to accumulate in fish tissues in quantities that reflect the exposure. Semipermeable
membrane devices (SPMDs) have been successfully used to mimic bioaccumulation of
hydrophobic organic substances in aquatic organisms. In order to assess exposure to or effects of
environmental pollutants on aquatic ecosystems, the following suite of fish biomarkers may be
examined: biotransformation enzymes (phase I and II), oxidative stress parameters,
biotransformation products, stress proteins, metallothioneins (MTs), MXR proteins,
hematological parameters, immunological parameters, reproductive and endocrine parameters,
genotoxic parameters, neuromuscular parameters, physiological, histological and morphological
parameters. All fish biomarkers are evaluated for their potential use in ERA programs, based
upon six criteria that have been proposed in the present paper. This evaluation demonstrates that
phase I enzymes (e.g. hepatic EROD and CYP1A), biotransformation products (e.g. biliary PAH
metabolites), reproductive parameters (e.g. plasma VTG) and genotoxic parameters (e.g. hepatic
DNA adducts) are currently the most valuable fish biomarkers for ERA. The use of
biomonitoring methods in the control strategies for chemical pollution has several advantages
over chemical monitoring. Many of the biological measurements form the only way of
integrating effects on a large number of individual and interactive processes in aquatic
organisms. Moreover, biological and biochemical effects may link the bioavailability of the
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