Comparison of short‐term chronic and chronic silver toxicity to fathead minnows in unamended and sodium chloride‐amended waters

Abstract

The chronic (early life stage [ELS]) and short-term chronic (STC) toxicity of silver (as silver nitrate) to fathead minnows (FHM) was determined concurrently in flow-through exposures (33 volume additions/d). Paired ELS (approximately 30 d) and STC (7 d) studies were conducted with and without the addition of 60 mg/L Cl (as NaCl). The paired studies in unamended water were later repeated using standard flow conditions (9 volume additions/d). The purpose of the paired studies was to determine if short-term chronic endpoints can be used to predict effects in ELS studies. For each experiment, a "split-chamber" design (organisms were held in a common exposure chamber) allowed the direct comparison between short-term and chronic exposures. It appeared that the chronic toxicity of silver was mitigated to some extent by NaCl addition. The maximum acceptable toxicant concentration for growth in the ELS study was 0.53 microg dissolved Ag/L under standard flow conditions. Early life stage and STC endpoints in all three studies typically agreed within a factor of two. Whole-body sodium and silver concentrations measured in individual fathead minnows during these studies showed an increase in silver body burdens and a decrease in sodium concentration. These results indicate that the STC study could be used as a surrogate test to estimate chronic toxicity and that the mechanism of chronic silver toxicity may be the same as for acute toxicity.

Evaluating the effects of pH, hardness, and dissolved organic carbon on the toxicity of aluminum to freshwater aquatic organisms under circumneutral conditions

“…An early-life-stage P. promelas test conducted by Cardwell et al [13] at pH 6, 120 mg/L hardness, and 0 mg/L DOC resulted in a biomass EC10 of 417 (95% CI: 151-1157) mg Al/L, which is comparable to the short-term chronic test result biomass EC10 of 481 (95% CI: 280-828) mg Al/L for identical test water conditions in the present study. The use of short-term chronic tests to reliably predict early-life-stage P. promelas toxicity has been demonstrated for other metals [28,38]. Therefore, the short-term chronic studies we present are reasonable predictors of earlylife-stage Al toxicity and should be considered for incorporation into criteria derivation.…”

“…No observable effects concentration for C. dubia and P. subcapitata filtration tests were calculated using Dunnett's multiple comparisons (statistics evaluated using EMSL Cincinnati Dunnett Software Ver 1.5, USEPA). Pairwise comparisons between ECxx values were considered significantly different statistically if the 95% confidence intervals (CIs) did not overlap [27,28]. Statistical analysis of the multivariate trends between Al toxicity and water quality characteristics were evaluated using data from the present study in the companion multiple linear regression (MLR) study [15], and a summary of those results is presented in the present study.…”

Effects of sodium chloride on chronic silver toxicity to early life stages of rainbow trout (Oncorhynchus mykiss)

“…In the only other study, to our knowledge, that included whole-body sodium concentration, Brauner and Wood [12] observed significant decreases in whole-body sodium concentration during chronic exposure of rainbow trout embryos and larvae to a much greater silver concentration, 10 g/L of nominal silver (10.7 g/L of total measured Ag). There appear to be mixed results on whether chronic silver exposure causes rainbow trout to lose wholebody sodium, but fathead minnows had consistently lower whole-body sodium concentrations in chronic silver exposures [9].…”

“…Assessments of chronic toxicity of silver to fish include a few studies on fathead minnows [7][8][9] as well as those investigating physiological effects in rainbow trout (Oncorhynchus mykiss) to elucidate the mechanism of silver toxicity [10][11][12][13]. Previous studies that have focused on chronic effects of silver on mortality and growth in rainbow trout [14,15] indicate increased sensitivity to silver for early life stages (ELS) ( Table 1).…”

Protein‐based electrochemical biosensor for detection of silver(I) ions

“…In aquatic ecosystems, heavy metal ions accumulate, and their distribution and bioavailability are higher compared with terrestrial ecosystems. Silver(I) ions are extremely toxic to aquatic animals [2][3][4][5][6][7]. The organisms viewed as most sensitive to silver(I) ions are small aquatic invertebrates, particularly in the embryonic and larval stages [8][9][10][11][12].…”