摘要:

Flagfish were exposed to cadmium and zinc as individual metals and as mixtures (4.3-8.5 μg Cd/liter and 73.4-139 μg Zn/liter) through one complete life cycle in Lake Superior water (45 mg/liter total hardness). Cadmium and zinc did not act additively at sublethal concentrations when combined as mixtures; however, a joint action of the toxicants was indicated. Effects on survival showed that the toxicity of cadmium and zinc mixtures was little if any greater than the toxicity of zinc alone. Mechanisms of zinc toxicity in this test were similar to those in previous chronic tests of individual metals, indicating that the presence of cadmium did not influence the mode of action of zinc. Comparisons between metal residues in fish exposed to each individual metal or to the metal mixtures showed that the uptake of one metal was not influenced by the presence of the other.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<354:CEOCAZ>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The toxicity of ammonia and of nitrite was tested on cutthroat trout (Salmo clarki) fry (1-3 g) for periods up to a month in eight laboratory flow-through bioassays. Median lethal concentration (LC50) values for ammonia (mg/liter un-ionized NH3) were 0.5-0.8 for 96 hours, and 0.3-0.6 for 36 days. Nitrite LC50 values (mg/liter NO2-N) were 0.5-0.6 for 96 hours, and 0.4 for 36 days. Tissues of fish exposed for 29 days to 0.34 mg/liter un-ionized ammonia evidenced degenerative changes in gills, kidneys, and livers. Cutthroat trout fry are comparable to rainbow trout (Salmo gairdneri) fry in their susceptibility to acute toxicity from aqueous ammonia and nitrite.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<361:ATOAAN>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Rainbow trout (Salmo gairdneri) were exposed to 0.5 and 2.0 μg/g doses of ethyl-mercury (p-toluene sulfonanilide) “Ceresan” each day for a full year and 2.5 and 10 μg/g doses delivered every 5th day of feeding during the year. A further study extended dose levels from 5.0 to 25.0 μg/g Ceresan given daily. Exposure to the lower doses of mercury for either feeding schedule led to concentrations of mercury in muscle that were similar (regression slope equaled one) to the average daily index of dose for as long as 6 months of feeding. Assessment of concentration in muscle at 9 months of feeding showed a breakdown of the effect in all groups except the one receiving 0.5 μg/g of Ceresan daily. Both dose level and schedules influenced the concentrations of mercury in muscle. Daily treatment with higher doses, e.g., 5.0 through 25.0 μg/g, led to dose-related concentrations of mercury in muscle but the regression was greater than one. Orders of mercury concentration in a variety of other tissues differed significantly and were generally related to dose. Fish receiving 10.0 μg/g of mercury every 5 days or 5.0 μg/g or greater doses every day in their feed were unable, with few exceptions, to learn to avoid shock when preceded by a signal-light. But beyond performance on the learning task, there was no evidence of impairment of general behavior nor was there any indication of physical debilitation resulting from any treatment. There appeared to be a fairly rapid loss of mercury from selected tissues, although estimates of total body burden of mercury remained high after 6 months of mercury-free feeding.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<369:MFS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Four species of fish were tested for tolerance to dissolved atmospheric gas supersaturation in 10-day bioassays. Based on median times to death at four levels of gas saturation, the fish displayed the following increasing order of tolerance: mountain whitefish (Prosopium williamsoni) < cutthroat trout (Salmo clarki) < largescale sucker (Catostomus machrocheilus) < torrent sculpin (Cottus rhotheus). Increasing hydrostatic pressure due to water depth reduced the levels of saturation of dissolved gases and increased survival. Torrent sculpins typically developed large bubbles of gas which caused them to float and would contribute indirectly to death.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<376:TOFTDG>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1978.10493145

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor