A relationship between gill silver accumulation and acute silver toxicity in the freshwater rainbow trout: support for the acute silver biotic ligand model.
Rainbow trout were exposed to a range of silver concentrations (as AgNO3) in flowing synthetic soft water (0.05 mM Na+, 0.05 mM Cl-, 0.05 mM Ca2+, 0.02 mM Mg2+, 0.02 mM K+, pH 7.0, approximately 0.7 mg C/L dissolved organic carbon, 10 mg CaCO3/L, 10 +/- 2 degrees C) to investigate a possible relationship between short-term gill silver accumulation (3 h or 24 h) and acute silver toxicity (96-h mortality). We also investigated potential relationships between gill silver accumulation and inhibition of Na+ uptake plus inhibition of gill Na+K(+)-adenosine triphosphatase (ATPase) activity. The 96-h median lethal concentration (LC50) values were 13.3 microg total Ag L(-1) and 3.3 microg dissolved Ag L(-1). A relationship was demonstrated between 3-h and 24-h gill silver accumulation and 96-h mortality. A relationship also was demonstrated between gill silver accumulation and inhibition of Na+ uptake at 24 h of exposure. No relationship between gill silver accumulation and inhibition of gill Na+K(+)-ATPase activity was found. The 96-h median lethal gill accumulation (LA50) values of 129 (at 3 h) and 191 ng g(-1) (at 24 h) and a conditional equilibrium binding constant of 8.0 for Ag+ binding to the gills were calculated. These observations support use of the silver biotic ligand model (BLM) as a regulatory tool to predict acute silver toxicity.
Morgan
Tammie P
TP
Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada. morgatp@mcmaster.ca
Wood
Chris M
CM
D000210:Acute-Phase Reaction; D000818:Animals; D005618:Fresh Water / Q000032:analysis; D005880:Gills / Q000737:chemistry*; D007928:Lethal Dose 50; D008954:Models, Biological; D009026:Mortality; D017686:Oncorhynchus mykiss; D012834:Silver / Q000032:analysis* / Q000633:toxicity*; D012835:Silver Nitrate / Q000378:metabolism / Q000633:toxicity; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013997:Time Factors
D012834:Silver; D012835:Silver Nitrate; D000254:Sodium-Potassium-Exchanging ATPase