EVALUATION AND APPLICATION OF AQUATIC TOXICITY TESTS - USE OF THE MICROTOX TEST FOR THE PREDICTION OF TOXICITY BASED UPON CONCENTRATIONS OFCONTAMINANTS IN SOIL
R. Galli et al., EVALUATION AND APPLICATION OF AQUATIC TOXICITY TESTS - USE OF THE MICROTOX TEST FOR THE PREDICTION OF TOXICITY BASED UPON CONCENTRATIONS OFCONTAMINANTS IN SOIL, Hydrobiologia, 273(3), 1994, pp. 179-189
The quality control for the reuse of cleaned soil from a contaminated
site consisted in the determination of the main contaminants by analyt
ical chemical methods such as GC and HPLC. Since it is not possible to
analyze for all contaminants a toxicity test should be used to detect
large concentrations of not routinely analyzed chemicals. The aim of
the study was to develop a system for toxicity testing, which should b
e able to predict the toxicity of soil samples based on the concentrat
ion of chemicals in the soil and to detect toxic chemicals not analyze
d by the routinely conducted soil analysis. Based upon the relative se
nsitivity to various contaminants as well as practical aspects such as
test duration and costs the Microtox(R) test was favoured over the bi
oassays with Daphnia magna and Scenedesmus subspicatus. The Microtox(R
) test was used to measure the toxicity of various pesticides and thei
r major metabolites. The toxicity data of the pure compounds were used
to predict the toxicity (EC50 and % inhibition of the bioluminescence
reaction) of defined mixtures of chemicals in water by applying two d
ifferent mathematical approaches which are based on the additivity of
the effects of the single chemicals. The predicted values were compare
d with the experimental data and showed good agreement. In order to be
able to predict the toxicity of soil samples using the Microtox(R) te
st the soil/water partition coefficient (K(d)) was measured for the ma
in contaminants. The toxicity of soil samples was predicted by calcula
ting the concentration of the contaminants in the leachate by using th
e corresponding concentration in the soil and applying the K(d) values
determined. From the calculated composition of the leachate the expec
ted toxicity was estimated. This value was compared with the toxicity
experimentally determined in the Microtox(R) test.