A relationship between gill silver accumulation and acute silver toxicity in the freshwater rainbow trout: Support for the acute silver biotic ligand model

Abstract

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.

Rhizotoxic effects of silver in cowpea seedlings

“…Seedlings were grown for 48 h, at which time the solutions averaged pH 5.8. Digital images were captured at the time of transfer (0 h) and 4,8,12,24,36, and 48 h thereafter. The length of each root was measured using UTHSCSA ImageTool 3.0 (University of Texas Health Science Center), available free of charge at http:// ddsdx.uthscsa.edu/dig/itdesc.html.…”

“…Lee et al [3], however, measured soluble Ag in filtered (0.2 mm) solutions, finding a median effective concentration that reduced growth by 50% (EC50) of 0.01 and 0.03 mM Ag for two freshwater algae. Likewise, Bianchini and Wood [5] found a median lethal concentration (LC50) of 0.03 mM Ag for Daphnia magna Straus in filtered (0.45 mm), moderately hard water, and Morgan and Wood [8] recorded the same LC50 value for rainbow trout in freshwater (also filtered to 0.45 mm).…”

“…Most research has focussed on the toxicity of Ag (specifically Ag þ ) to freshwater and marine organisms, such as algae [3], invertebrates [4][5][6], and fish, including rainbow trout (Oncorhynchus mykiss Walbaum) [7,8]. Wood et al [2] concluded that ''the acute toxicity of Ag (to rainbow trout) appears to be caused solely by ionic Ag þ interacting at the gills, inhibiting basolateral Na þ , K þ -ATPase activity,'' thereby disrupting osmoregulation.…”

Modeling chemical speciation of copper in River Yamuna at Delhi, India

“…The next generation equilibrium models such as REDEQL (Morel and Morgan, 1972) and GEOCHEM (Sposito and Mattigod, 1980) incorporated methods of convergence, interfacing NewtonRaphson and successive approximation methods. The Biotic Ligand Model (BLM, Pagenkopf, 1983), almost a derivative of the Free-Ion Model (FIM), is a recent development relating chemical forms of metals with toxicity to organisms (Bell et al, 2002;Campbell 2002;Campbell et al, 2002;Chapman et al, 2003;Di Toro et al, 2001;McGeer et al, 2000;Morgan and Wood, 2004;Playle, 1998;Playle et al, 1993;Tipping, 1994). The model aims at predicting interactions of dissolved metals with aquatic organisms that eventually affect them.…”

OECD Series on Testing and Assessment

“…Additional references (e.g., publications that only focus on the metalgill binding interaction) can be found in Ardestani et al (2014). Ag Bury et al, 2002;Janes and Playle, 1995;McGeer et al, 2000;Morgan and Wood, 2004;Paquin et al, 1999. As Chen et al, 2009.…”