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At least 577 records · Page 32Linked to original sources

Toxicity and efficacy of Furanace on channel catfish Ictalurus punctatus (Rafinesque) infected experimentally with Aeromonas hydrophila

The 96-h medium tolerance limit of Furanace (nifurpirinol: P-7138) for channel catfish Ictalurus punctatus at 21°C was 0-94 mg/1. The most effective treatment level for channel catfish, experimentally infected with Aeromonas hydrophila , was 2mg/1 for 6.5 h. Furanace at 0.5 and 1.0 mg/1 in brain heart infusion agar reduced in vitro growth of A. hydrophila and at 2.0 mg/1 growth was completely.

Journal of Fish Diseases↗

Characterisation of carbon nanotubes in the context of toxicity studies

Nanotechnology has the potential to revolutionise our futures, but has also prompted concerns about the possibility that nanomaterials may harm humans or the biosphere. The unique properties of nanoparticles, that give them novel size dependent functionalities, may also have the potential to cause harm. Discrepancies in existing human health and environmental studies have shown the importance of good quality, well-characterized reference nanomaterials for toxicological studies. Here we make a case for the importance of the detailed characterization of nanoparticles, using several methods, particularly to allow the recognition of impurities and the presence of chemically identical but structurally distinct phases. Methods to characterise fully, commercially available multi-wall carbon nanotubes at different scales, are presented.

Environmental Health↗

The global transport of dust: An intercontinental river of dust, microorganisms and toxic chemicals flows through the Earth's atmosphere

The coral reefs in the Caribbean have been deteriorating since the 1970s, and no one is quite sure why. Such environmental devastation is usually blamed on Homo sapiens , but that doesn’t seem to be what’s going on here. Recently, some scientists at the USGS think they’ve solved the puzzle: Bacteria and fungi have been hitching trans-Atlantic rides on dust from the Sahara desert and settling into the warm waters of the Caribbean. Microbiologist Dale Griffin and his colleagues make the case for this hypothesis and explore the dangers of dust and microbe transport across the globe.

American Scientist↗

Relative toxicity of suspension and oil formulations of DDT to native fishes in Back Creek, West Virginia

On July 23, 1947, a 1‐mile section of Back Creek, treated the previous year with a DDT suspension with little damage to fish, was re‐treated with an oil spray at the same rate (1 pound per acre). The oil spray killed about six times as many fish as the suspension formula. Fish began dying within 3 to 4 hours after treatment, whereas several days elapsed before mortality began with the suspension formula in 1946. In addition to larger numbers of the minnow species, some adult game fish were killed. Losses of fish were not as great below the sprayed section as when a suspension formula was used, probably because a good part of the DDT was drifted ashore by breezes or by water currents. Some species of fish such as bluntnose minnows (Hyborhynchus notatus), chub suckers (Erimyzon oblongus), and pickerel (Esox niger), although numerous, were relatively unaffected. Considerable mortality of largemouth bass (Micropterus salmoides) and bluegill sunfish (Lepomis macrochirus) occurred in liveboxes placed in the sprayed section, particularly at the lower stations. Largemouth bass nearly 4 inches long survived at a station where 54.0 percent of the 2‐inch bass were killed. This fact supplied some positive evidence that fish of larger size are better able to withstand DDT.

West Virginia↗

Sulfonamide toxicity in brook trout

Sterility was observed in female brook trout that were treated with sulfamerazine at frequent intervals for 2 years to control endemic furunculosis. Feeding sulfamerazine for a period of 8 months caused massive kidney damage similar to that observed in humans who develop allergies to “sulfa” drugs. Kidney damage of the type observed would probably cause renal insufficiency which would handicap any physiological function including reproduction. Feeding sulfonamides for periods up to 13 weeks did not produce kidney damage.

Transactions of the American Fisheries Society↗

Toxicity of TFM lampricide to early life stages of walleye

We studied the effects of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) on gametes, newly fertilized eggs, eyed eggs, larvae, and swim-up fry of the walleye Stizostedion vitreum . When gametes from sexually mature walleyes were stripped into solutions of TFM, no effects were observed during the fertilization process at concentrations up to 3.0 mg/L—three times the concentration lethal to 99.9% of larval sea lampreys Petromyzon marinus held 12 h (LC99.9) under the same test conditions. Newly fertilized eggs likewise were unaffected during water hardening by concentrations of TFM that were lethal to sea lamprey ammocoetes. Eyed eggs, sac fry, and swim-up fry yielded LC25 values that were 2.5 to 5 times greater than the 12-h LC99.9 for sea lamprey ammocoetes. The data thus indicated that all of the early life stages of walleyes tested were considerably more resistant than sea lamprey ammocoetes to TFM, and that it is unlikely they would be adversely affected by standard stream treatments to kill sea lamprey ammocoetes.

North American Journal of Fisheries Management↗

Importance of equilibration time in the partitioning and toxicity of zinc in spiked sediment bioassays

The influences of spiked Zn concentrations (1–40 μmol/g) and equilibration time (˜ 95 d) on the partitioning of Zn between pore water (PW) and sediment were evaluated with estuarine sediments containing two levels (5 and 15 μmol/g) of acid volatile sulfides (AVS). Their influence on Zn bioavailability was also evaluated by a parallel, 10‐d amphipod ( Leptocheirus plumulosus ) mortality test at 5, 20, and 85 d of equilibration. During the equilibration, AVS increased (up to twofold) with spiked Zn concentration ([Zn]), whereas Zn‐simultaneously extracted metals ([SEM]; Zn with AVS) remained relatively constant. Concentrations of Zn in PW decreased most rapidly during the initial 30 d and by 11‐ to 23‐fold during the whole 95‐d equilibration period. The apparent partitioning coefficient ( K pw , ratio of [Zn] in SEM to PW) increased by 10‐ to 20‐fold with time and decreased with spiked [Zn] in sediments. The decrease of PW [Zn] could be explained by a combination of changes in AVS and redistribution of Zn into more insoluble phases as the sediment aged. Amphipod mortality decreased significantly with the equilibration time, consistent with decrease in dissolved [Zn]. The median lethal concentration (LC50) value (33 μM) in the second bioassay, conducted after 20 d of equilibration, was twofold the LC50 in the initial bioassay at 5 d of equilibration, probably because of the change of dissolved Zn speciation. Sediment bioassay protocols employing a short equilibration time and high spiked metal concentrations could accentuate partitioning of metals to the dissolved phase and shift the pathway for metal exposure toward the dissolved phase.

Environmental Toxicology and Chemistry↗