摘要:

AbstractRainbow(Salmo gairdneri)and steelhead(Salmogairdneri)trout and fathead minnows(Pimephales promelas)were exposed to silver for 96 h in replicated flow‐through tests. Rainbow trout, fathead minnows andDaphnia magnawere exposed to silver in replicated static acute tests. Steelhead trout embryo‐larval stages were tested in a flow‐through system for 60 d, andD. magnawere exposed through complete life cycles in replicated static‐renewal tests. All silver concentrations were measured values. No differences were seen between flow‐through and static LC50values. Rainbow trout 96‐h flow‐through LC50values were 8.6 and 9.7 μg/L silver; static values were 10.9 and 8.5 μg/L. The 96‐h LC50for steelhead trout in the flow‐through test was 9.2 μg/L. Fathead minnow 96‐h flow‐through LC50values were 5.6 and 7.4 μg/L silver; static values were 9.4 and 9.7 μg/L. The absence of food in static tests withD. magnacaused silver to be about 10 times more toxic; the 48‐h static mean EC50value forD. magnawithout food was 0.9 μg/L, compared to 12.5 μg/L in the test with food. The early‐life‐stage test with steelhead trout, from newly fertilized eggs to post‐swimup juveniles, showed complete mortality at 1.3 μg/L and significant reduction in fish survival at 0.5 μg/L silver. Mean weight and length at end of test were greatly reduced at 1.1 μg/L, and were significantly different from controls at 0.1 μg/L. The mean 21‐d EC50value for theD. magnatest with food was 3.5 μg/L. The 21‐d lowest significant (α = 0.05) effect on survival occurred at 4.1 μg/L. The mean silver concentration at which there was a significant decrease in totalDaphniayoung/female/day after 21

ISSN:0730-7268    

DOI:10.1002/etc.5620020111

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe first comprehensive evaluation of the environmental safety of three similar cationic surfactants to aquatic life is reported. Toxicity tests were conducted that exposed freshwater and marine species, representing three trophic levels, to the dialkyl dimethyl ammonium compounds. The studies were conducted in a high‐quality laboratory water and in river waters that were used to model realistic receiving streams. Most current laboratory test methods for the assessment of chemical effects on aquatic life do not consider the physical and chemical properties of the test material in surface waters. This safety assessment shows that these considerations are important in developing realistic conclusions about the ecological safety of cationic surfactants. In tests using river water, acute and chronic toxicities and bioconcentration were considerably less than those in corresponding tests conducted in filtered laboratory waters. This reduction in toxicity and/or uptake was attributable to the aqueous insolubility of the surfactants, strong adsorption to natural solids and tendency to form chemical complexes with anionic substances. The mean ratio of the concentration of anionic to cationic surfactants in municipal sewage treatment plant effluent is 4:1. Safety margins were calculated for daphnids and fathead minnows using the ratio of the no observed effect concentration, determined from chronic toxicity tests, to mean measured surface water concentrations. Safety margins for fish and daphnids were 7 and 11, respectively, for a river having a low wastewater effluent dilution factor of 10. For a river with a higher dilution factor of 150, the values were 115 (fish) and 190 (daphnids). Projected safety margins for marine invertebrates and fish were several orders of magnitude greater than those for freshwater species. Based on available information and expected usage levels, the projected environmental impact of these surfactants on aquatic life is minima

ISSN:0730-7268    

DOI:10.1002/etc.5620020112

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractColonized Hester‐Dendy substrates were deployed for 96 h in an urban river reach, storm drain channel and a control site to assess the toxicity of urban runoff. The mean macroinver‐tebrate diversity during rain events was reduced from 1.7 at the control station to 1.0 at both urban stations. Snowmelt exerted the same effect on river substrate diversity, but only reduced channel values from 2.0 to 1.4. During periods of no runoff, however, mean channel and control diversities remained the same (1.5), while river values dropped to 0.8. Similarly, substrate population densities during rain were, respectively, two and seven times more limiting for the storm drain channel and river reach stations. The same trend was evident in heavy metals uptake, indicating that dry weather toxicity in urban river reaches originates from the sediments. Runoff, then, serves to reduce toxicity during input, but increases it over the long

ISSN:0730-7268    

DOI:10.1002/etc.5620020113

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

ISSN:0730-7268    

DOI:10.1002/etc.5620020114

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY