The relative importance of water hardness and chloride levels in modifying the acute toxicity of silver to rainbow trout (Oncorhynchus mykiss)

Journal Article · Sat Nov 01 04:00:00 EST 1997 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1002/etc.5620161123· OSTI ID:563958

Galvez, F; Wood, C M ^[1]

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1. McMaster Univ., Hamilton, Ontario (Canada). Dept. of Biology

Static-renewal 7-d toxicity tests for silver nitrate (AgNO{sub 3}) were performed with juvenile rainbow trout (Oncorhynchus mykiss Walbaum). The relative influences of calcium and chloride concentrations on median lethal time (LT50) were assessed. For both calcium salts, a 100-fold elevation in concentration increased the LT50 approximately 10-fold. However, a 100-fold elevation in KCl ameliorated silver (Ag) toxicity at least 100-fold, while NaCl protected against Ag toxicity even more substantially, demonstrating the much greater protective effect of chloride relative to calcium. In a separate series of bioassays, fish were exposed to 0.92 {micro}M Ag with varying amounts of NaCl titrated into each tank to alter the free [Ag{sup +}]. The 7-d LC50 occurred at a [NaCl] of 2,500 {micro}M. Using MINEQL{sup +}, the predicted free [Ag{sup +}] at this LC50 value is 0.0285 {micro}M. Further bioassays were performed in which [chloride] was maintained at either 50 or 225 {micro}M, while total [Ag] was independently varied from 0.0092 to 0.0694 {micro}M (1.0--7.5 {micro}g/L). The 7-d LC50 value was calculated at 0.0294 {micro}M Ag (3.18 {micro}g/L) at a chloride concentration of 50 {micro}M, very similar to the free [Ag{sup +}] value of 0.031 {micro}M calculated from an earlier LC50 test at a fixed [chloride] of 730 {micro}M. Elevating chloride concentrations from 50 to 225 {micro}M did not alter the accumulation of Ag in the liver. In addition, there were no significant differences in hepatic Ag accumulation between any of the Ag-exposed fish, irrespective of the total Ag concentration used during the exposure.

• Sponsoring Organization: USDOE
• OSTI ID: 563958
• Journal Information: Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 11 Vol. 16; ISSN 0730-7268; ISSN ETOCDK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOLOGICAL AVAILABILITY
BIOLOGICAL INDICATORS
CHLORIDES
PH VALUE
RESPONSE MODIFYING FACTORS
SILVER
TOXICITY
TROUT
WATER POLLUTION