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Peter F Landrum – One of the best experts on this subject based on the ideXlab platform.

  • effects of proposed physical ballast tank treatments on Aquatic Invertebrate resting eggs
    Environmental Toxicology and Chemistry, 2007
    Co-Authors: David F Raikow, David F Reid, Ernest R Blatchley, Gregory R Jacobs, Peter F Landrum

    Abstract:

    Adaptations in Aquatic Invertebrate resting eggs that confer protection from natural catastrophic events also could confer protection from treatments applied to ballast water for biological invasion vector management. To evaluate the potential efficacy of physical ballast water treatment methods, the present study examined the acute toxicity of heat (flash and holding methods), ultraviolet (UV) radiation (254 nm), and deoxygenation (acute and chronic) on resting eggs of the freshwater cladoceran Daphnia mendotae and the marine brine shrimp Artemia sp. Both D. mendotae and Artemia sp. were similarly sensitive to flash exposures of heat (100% mortality at 70 degrees C), but D. mendotae were much more sensitive to prolonged exposures. Exposure to 4,000 mJ/cm2 of UV radiation resulted in mortality rates of 59% in Artemia sp. and 91% in D. mendotae. Deoxygenation to an oxygen concentration of 1 mg/L was maximally toxic to both species. Deoxygenation suppressed hatching of D. mendotae resting eggs at oxygen concentrations of less than 5.5 mg/L and of Artemia sp. resting eggs at concentrations of less than 1 mg/L. Results suggest that UV radiation and deoxygenation are not viable treatment methods with respect to Invertebrate resting eggs because of the impracticality of producing sufficient UV doses and the suppression of hatching at low oxygen concentrations. Results also suggest that the treatment temperatures required to kill resting eggs are much higher than those reported to be effective against other Invertebrate life stages and species. The results, however, do not preclude the effectiveness of these treatments against other organisms or life stages. Nevertheless, if ballast tank treatment systems employing the tested methods are intended to include mitigation of viable resting eggs, then physical removal of large resting eggs and ephippia via filtration would be a necessary initial step.

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  • sensitivity of Aquatic Invertebrate resting eggs to seakleen menadione a test of potential ballast tank treatment options
    Environmental Toxicology and Chemistry, 2006
    Co-Authors: David F Raikow, David F Reid, Erynn E Maynard, Peter F Landrum

    Abstract:

    The introduction of Aquatic species in resting life stages by the release of ballast water is a less well-known but potentially important invasive species vector. Best-management practices designed to minimize transport of ballast water cannot eliminate this threat, because residual water and sediment are retained in ballast tanks after draining. To evaluate the potential efficacy of chemical treatment of residual material in ship ballast tanks, the present study examined the acute toxicity of the proposed biocide SeaKleen (menadione; Garnett, Watkinsville, GA, USA) on resting eggs of Brachionus plicatilis (a marine rotifer), a freshwater copepod, Daphnia mendotae (a freshwater cladoceran), and Artemia sp. (a marine brine shrimp). SeaKleen was toxic to resting eggs of all taxa. Daphnia mendotae resting eggs encased in protective ephippia were the least sensitive, as indicated by a 24-h lethal con- centration of toxicant to 90% of organisms of 8.7 mg/L (95% confidence interval, 0.1 mg/L). SeaKleen induced teratogenic effects in D. mendotae and Artemia sp. Exposure to sunlight quickly degraded SeaKleen, which lost all toxicity after 72 h outdoors. SeaKleen increased in toxicity slightly after 72 h in darkness. Burial of D. mendotae ephippia in natural lake sediment reduced SeaKleen toxicity by a factor of 20. Reduced toxicity in the presence of sediment raises serious doubts as to the potential for this, or any, chemical biocide to kill Aquatic Invertebrate resting stages buried in sediment retained in ship ballast tanks. Keywords—Resting egg Biological invasion Ballast SeaKleen Menadione

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David F Raikow – One of the best experts on this subject based on the ideXlab platform.

  • effects of proposed physical ballast tank treatments on Aquatic Invertebrate resting eggs
    Environmental Toxicology and Chemistry, 2007
    Co-Authors: David F Raikow, David F Reid, Ernest R Blatchley, Gregory R Jacobs, Peter F Landrum

    Abstract:

    Adaptations in Aquatic Invertebrate resting eggs that confer protection from natural catastrophic events also could confer protection from treatments applied to ballast water for biological invasion vector management. To evaluate the potential efficacy of physical ballast water treatment methods, the present study examined the acute toxicity of heat (flash and holding methods), ultraviolet (UV) radiation (254 nm), and deoxygenation (acute and chronic) on resting eggs of the freshwater cladoceran Daphnia mendotae and the marine brine shrimp Artemia sp. Both D. mendotae and Artemia sp. were similarly sensitive to flash exposures of heat (100% mortality at 70 degrees C), but D. mendotae were much more sensitive to prolonged exposures. Exposure to 4,000 mJ/cm2 of UV radiation resulted in mortality rates of 59% in Artemia sp. and 91% in D. mendotae. Deoxygenation to an oxygen concentration of 1 mg/L was maximally toxic to both species. Deoxygenation suppressed hatching of D. mendotae resting eggs at oxygen concentrations of less than 5.5 mg/L and of Artemia sp. resting eggs at concentrations of less than 1 mg/L. Results suggest that UV radiation and deoxygenation are not viable treatment methods with respect to Invertebrate resting eggs because of the impracticality of producing sufficient UV doses and the suppression of hatching at low oxygen concentrations. Results also suggest that the treatment temperatures required to kill resting eggs are much higher than those reported to be effective against other Invertebrate life stages and species. The results, however, do not preclude the effectiveness of these treatments against other organisms or life stages. Nevertheless, if ballast tank treatment systems employing the tested methods are intended to include mitigation of viable resting eggs, then physical removal of large resting eggs and ephippia via filtration would be a necessary initial step.

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  • sensitivity of Aquatic Invertebrate resting eggs to seakleen menadione a test of potential ballast tank treatment options
    Environmental Toxicology and Chemistry, 2006
    Co-Authors: David F Raikow, David F Reid, Erynn E Maynard, Peter F Landrum

    Abstract:

    The introduction of Aquatic species in resting life stages by the release of ballast water is a less well-known but potentially important invasive species vector. Best-management practices designed to minimize transport of ballast water cannot eliminate this threat, because residual water and sediment are retained in ballast tanks after draining. To evaluate the potential efficacy of chemical treatment of residual material in ship ballast tanks, the present study examined the acute toxicity of the proposed biocide SeaKleen (menadione; Garnett, Watkinsville, GA, USA) on resting eggs of Brachionus plicatilis (a marine rotifer), a freshwater copepod, Daphnia mendotae (a freshwater cladoceran), and Artemia sp. (a marine brine shrimp). SeaKleen was toxic to resting eggs of all taxa. Daphnia mendotae resting eggs encased in protective ephippia were the least sensitive, as indicated by a 24-h lethal con- centration of toxicant to 90% of organisms of 8.7 mg/L (95% confidence interval, 0.1 mg/L). SeaKleen induced teratogenic effects in D. mendotae and Artemia sp. Exposure to sunlight quickly degraded SeaKleen, which lost all toxicity after 72 h outdoors. SeaKleen increased in toxicity slightly after 72 h in darkness. Burial of D. mendotae ephippia in natural lake sediment reduced SeaKleen toxicity by a factor of 20. Reduced toxicity in the presence of sediment raises serious doubts as to the potential for this, or any, chemical biocide to kill Aquatic Invertebrate resting stages buried in sediment retained in ship ballast tanks. Keywords—Resting egg Biological invasion Ballast SeaKleen Menadione

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Karsten Liber – One of the best experts on this subject based on the ideXlab platform.

  • uranium uptake and depuration in the Aquatic Invertebrate chironomus tentans
    Environmental Pollution, 2010
    Co-Authors: Jorgelina R Muscatello, Karsten Liber

    Abstract:

    Abstract Evaluation of aqueous uranium (U) uptake and depuration in larvae of the midge Chironomus tentans were investigated in two separated experiments. First, a static-renewal experiment was performed with 10-d old C. tentans larvae exposed to 300 μg U/L. The animals steadily accumulated U ( K u  = 20.3) approaching steady-state conditions (BAF = 56) in approximately 9–11 d. However, accumulated U was readily depurated ( K d  = 0.36) with U tissue concentration decreasing rapidly within 3 d of the larvae being placed in clean water ( t 1/2  = 1.9 d). Also, the growth of C. tentans larvae appeared to decrease after 6–11 d of U exposure, probably due to the reallocation of resources into U detoxification mechanisms. However, growth significantly increased once C. tentans were transferred to clean water. A separate short-term experiment was performed to evaluate the possible mechanism of U uptake in this Invertebrate. Results suggested a passive mechanism of U uptake coupled with an active mechanism of U depuration but no details related to the type of mechanisms or pathway was investigated.

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  • accumulation and chronic toxicity of uranium over different life stages of the Aquatic Invertebrate chironomus tentans
    Archives of Environmental Contamination and Toxicology, 2009
    Co-Authors: Jorgelina R Muscatello, Karsten Liber

    Abstract:

    Limited data are available on the effects of uranium (U) exposures on benthic macroInvertebrates, something that would be needed before national or provincial water quality guidelines could be developed. The goal of this study was to evaluate chronic U toxicity and accumulation in the Aquatic Invertebrate Chironomus tentans. Test organisms were exposed to three aqueous U concentrations (40, 200, and 1,000 μg/L) and an untreated control. Larval growth, adult emergence, and U tissue concentrations at different life stages were evaluated. The measured no-observed-effect concentration (NOEC) and lowest-observed-effect concentration (LOEC) for growth of C. tentans larvae after 10 days of U exposure were 39 and 157 μg/L, respectively. At U concentrations >157 ug/L, there was reduced larval growth of 30% to 40%, which corresponded to reduced adult emergence of 40% to 60%. Despite significant delays in time to adult emergence, there were no significant effects on reproductive output of successfully emerged adults. The F1 generation C. tentans larvae that were never directly exposed to U, but originated from adult males and females exposed to U during their immature life stages, displayed a significant decrease in 10-day growth that was similar to that observed for the F0-exposed larvae. This suggests that the environment of the parental generation can significantly influence the development of the next generation through environmentally induced parental effects. Uranium accumulated in C. tentans immature stages was partially excreted during molting and metamorphosis to the adult stage. However, the elimination of U was not complete and some was still measured in adult midges. Consequently, a minor transfer of U from the Aquatic to the terrestrial environment could be expected to occur.

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