Handbook of Solvents - George Wypych - ChemTech - Ventech!

1106 James L. Botsford
Table 15.2.2.3. Comparisons for involving Rhizobium, Microtox TM , HLD, IC50, Daphnia
magna and rats
n r 2
n r 2
Rhizobium x Microtox TM
34 0.875 Rats x IC50 19 0.724
Rhizobium x rats 34 0.603 Rats x HLD 27 0.817
Rhizobium x IC50 20 0.906 Rats x Daphnia 32 0.685
Rhizobium x HLD 34 0.628 Rats x rat hepatocytes 34 0.748
Rhizobium x Daphnia 34 0.888 IC50 x HLD 16 0.732
Rhizobium x rat hepatocytes 34 0.764 IC50 x Daphnia 29 0.879
Microtox x rats 34 0.571 IC50 x rat hepatocytes 20 0.700
Microtox x IC50 24 0.840 HLD x rat hepatocytes 26 0.648
Microtox x HLD 31 0.728 HLD x Daphnia 29 0.702
Microtox x rat hepatocytes 33 0.700 Daphnia x rat hepatocytes 33 0.814
Microtox x Daphnia 34 0.846
n = number of samples in the test. One test was compared with another, the log of the values plotted, a regression
line fit and the correlation coefficient determined from the regression coefficient, r 2 .
The data for rats, Daphnia, HLD is from Calleja et al., 1994. The data for IC50 is from Halle et al., 1992. The data
for rat hepatocytes is from Shrivastava et al., 1992.
In Table 15.2.2.4, the results of these comparisons with the results of the Rhizobium
test are presented. The Rhizobium test correlates well with Microtox TM , Daphnia, and particularly
well with the 20 samples in the IC50 test. The comparison of the Rhizobium assays
with other published results has been examined in detail (Botsford, 2000a). The Rhizobium
test has been compared with values from several laboratories for the Microtox TM assay and
correlation coefficients have varied from 0.750 to 0.893 indicating the two methods provide
comparable results. Four comparisons with values for Daphnia have provided correlation
coefficients from 0.776 to 0.953 indicating that the Rhizobium assay agrees well with Daphnia.
QSAR provides a method to predict the toxicity of a compound from the structure of
the compound and the water/octanol partition coefficient (Nirmilkhandan and Speece,
1988). This method has been compared with assays using sewage sludge and Polytox TM
(Sun et al., 1993). The method compares well with both these other techniques. An examination
of the data provided by tests for toxic chemicals using these techniques suggested
that they are not as sensitive as more direct methods for determining toxicity. It was found
that Microtox TM , rat hepatocytes, the Rhizobium assay, and Daphnia all provided more sensitivity
to toxic chemicals than did the QSAR estimates (Botsford, 2000a). The IC50 values
for these other techniques were lower than those computed using the QSAR method. QSAR
data are not often found in the literature.