Jc. Mcgeer et al., A physiologically based biotic ligand model for predicting the acute toxicity of waterborne silver to rainbow trout in freshwaters, ENV SCI TEC, 34(19), 2000, pp. 4199-4207
Citations number
37
Categorie Soggetti
Environment/Ecology,"Environmental Engineering & Energy
An early silver-gill binding model using conditional equilibrium binding co
nstants (K) was fitted to actual toxicity data for rainbow trout (Oncorhync
hus mykiss) and subsequently modified to produce a mechanistically based ac
ute toxicity model for predicting silver toxicity. The model used an "off t
he shelf" aquatic geochemistry software program (MINEQL(+)) and physiologic
ally based log K values to predict the acute effects of waterborne silver i
n rainbow trout. The final version of the model does not predict total gill
-silver loading, as the early model did, but rather predicts the binding of
Ag+ to key toxic sites on the gill and incorporates the effects of cation
competition at these sites. The acute toxicity model for Ag+ provided the b
est fit to toxicity data when a log K value for the affinity of these sites
was 7.6 with cationic competition log K values for Na+ and Ca2+ of 2.9 and
2.3, respectively. A log K for Ag-DOM of 9.0 was used representing strong
Ag+ binding to dissolved organic matter. The model we present is easy to us
e and provides a good match with previously published acute AgNO3 toxicity
data for rainbow trout from 31 data sets in 10 studies. The modified model
is now ready for full verification with a greater range of laboratory and n
atural waters.