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Paul K. Sibley - One of the best experts on this subject based on the ideXlab platform.

  • Chronic Toxicity of the synthetic hormone 17α ethinylestradiol to chironomus tentans and hyalella azteca
    Environmental Toxicology and Chemistry, 2008
    Co-Authors: Keith R. Solomon, Ève B. Dussault, Vimal K. Balakrishnan, Paul K. Sibley
    Abstract:

    The Chronic Toxicity of the synthetic hormone 17α-ethinylestradiol (EE2) was investigated in two benthic invertebrates, the midge Chironomus tentans and the freshwater amphipod Hyalella azteca, in life-cycle water-only assays. In C. tentans, a 50% decrease in emergence was observed at a concentration of 1.5 mg/L; emergence was a more sensitive endpoint than survival, growth, or biomass. Reproduction was not significantly affected by EE2 exposure until a concentration of 3.1 mg/L, where emergence, and therefore reproduction, did not occur. In contrast, reproduction was the most sensitive endpoint in H. azteca (50% decrease in reproduction observed at a concentration of 0.36 mg/L). The sensitivity of the F1 generation to EE2 was also investigated with H. azteca, but was not different from the F0 generation. The data from the present study were combined with those from previous 10-d Toxicity assays, to derive acute to Chronic Toxicity ratios (ACRs) for EE2. The ACRs calculated for EE2 were 13 for C. tentans and 16 for H. azteca, indicating that the application factors currently used in ecological risk assessment for the derivation of Chronic Toxicity are protective and conservative for these organisms. The results of the present study suggest that Chronic Toxicity was not mediated by disruption of endocrine pathways. Using a hazard quotient approach, the risk associated with sublethal exposure to EE2 was << 1 for H. azteca and C. tentans, indicating that adverse effects are not expected, and that environmental exposure to EE2 likely poses a low risk to benthic invertebrates.

  • Chronic Toxicity of the synthetic hormone 17α‐Ethinylestradiol to Chironomus tentans and Hyalella azteca
    Environmental toxicology and chemistry, 2008
    Co-Authors: Ève B. Dussault, Keith R. Solomon, Vimal K. Balakrishnan, Paul K. Sibley
    Abstract:

    The Chronic Toxicity of the synthetic hormone 17α-ethinylestradiol (EE2) was investigated in two benthic invertebrates, the midge Chironomus tentans and the freshwater amphipod Hyalella azteca, in life-cycle water-only assays. In C. tentans, a 50% decrease in emergence was observed at a concentration of 1.5 mg/L; emergence was a more sensitive endpoint than survival, growth, or biomass. Reproduction was not significantly affected by EE2 exposure until a concentration of 3.1 mg/L, where emergence, and therefore reproduction, did not occur. In contrast, reproduction was the most sensitive endpoint in H. azteca (50% decrease in reproduction observed at a concentration of 0.36 mg/L). The sensitivity of the F1 generation to EE2 was also investigated with H. azteca, but was not different from the F0 generation. The data from the present study were combined with those from previous 10-d Toxicity assays, to derive acute to Chronic Toxicity ratios (ACRs) for EE2. The ACRs calculated for EE2 were 13 for C. tentans and 16 for H. azteca, indicating that the application factors currently used in ecological risk assessment for the derivation of Chronic Toxicity are protective and conservative for these organisms. The results of the present study suggest that Chronic Toxicity was not mediated by disruption of endocrine pathways. Using a hazard quotient approach, the risk associated with sublethal exposure to EE2 was

Ève B. Dussault - One of the best experts on this subject based on the ideXlab platform.

  • Chronic Toxicity of the synthetic hormone 17α ethinylestradiol to chironomus tentans and hyalella azteca
    Environmental Toxicology and Chemistry, 2008
    Co-Authors: Keith R. Solomon, Ève B. Dussault, Vimal K. Balakrishnan, Paul K. Sibley
    Abstract:

    The Chronic Toxicity of the synthetic hormone 17α-ethinylestradiol (EE2) was investigated in two benthic invertebrates, the midge Chironomus tentans and the freshwater amphipod Hyalella azteca, in life-cycle water-only assays. In C. tentans, a 50% decrease in emergence was observed at a concentration of 1.5 mg/L; emergence was a more sensitive endpoint than survival, growth, or biomass. Reproduction was not significantly affected by EE2 exposure until a concentration of 3.1 mg/L, where emergence, and therefore reproduction, did not occur. In contrast, reproduction was the most sensitive endpoint in H. azteca (50% decrease in reproduction observed at a concentration of 0.36 mg/L). The sensitivity of the F1 generation to EE2 was also investigated with H. azteca, but was not different from the F0 generation. The data from the present study were combined with those from previous 10-d Toxicity assays, to derive acute to Chronic Toxicity ratios (ACRs) for EE2. The ACRs calculated for EE2 were 13 for C. tentans and 16 for H. azteca, indicating that the application factors currently used in ecological risk assessment for the derivation of Chronic Toxicity are protective and conservative for these organisms. The results of the present study suggest that Chronic Toxicity was not mediated by disruption of endocrine pathways. Using a hazard quotient approach, the risk associated with sublethal exposure to EE2 was << 1 for H. azteca and C. tentans, indicating that adverse effects are not expected, and that environmental exposure to EE2 likely poses a low risk to benthic invertebrates.

  • Chronic Toxicity of the synthetic hormone 17α‐Ethinylestradiol to Chironomus tentans and Hyalella azteca
    Environmental toxicology and chemistry, 2008
    Co-Authors: Ève B. Dussault, Keith R. Solomon, Vimal K. Balakrishnan, Paul K. Sibley
    Abstract:

    The Chronic Toxicity of the synthetic hormone 17α-ethinylestradiol (EE2) was investigated in two benthic invertebrates, the midge Chironomus tentans and the freshwater amphipod Hyalella azteca, in life-cycle water-only assays. In C. tentans, a 50% decrease in emergence was observed at a concentration of 1.5 mg/L; emergence was a more sensitive endpoint than survival, growth, or biomass. Reproduction was not significantly affected by EE2 exposure until a concentration of 3.1 mg/L, where emergence, and therefore reproduction, did not occur. In contrast, reproduction was the most sensitive endpoint in H. azteca (50% decrease in reproduction observed at a concentration of 0.36 mg/L). The sensitivity of the F1 generation to EE2 was also investigated with H. azteca, but was not different from the F0 generation. The data from the present study were combined with those from previous 10-d Toxicity assays, to derive acute to Chronic Toxicity ratios (ACRs) for EE2. The ACRs calculated for EE2 were 13 for C. tentans and 16 for H. azteca, indicating that the application factors currently used in ecological risk assessment for the derivation of Chronic Toxicity are protective and conservative for these organisms. The results of the present study suggest that Chronic Toxicity was not mediated by disruption of endocrine pathways. Using a hazard quotient approach, the risk associated with sublethal exposure to EE2 was

Letícia Veras Costa-lotufo - One of the best experts on this subject based on the ideXlab platform.

  • Development of a short-term Chronic Toxicity test with a tropical mysid.
    Marine pollution bulletin, 2016
    Co-Authors: Lívia Pitombeira De Figuerêdo, Jeamylle Nilin, Allyson Queiroz Da Silva, Susana Loureiro, Letícia Veras Costa-lotufo
    Abstract:

    There is an increasing need to develop reliable methodologies for Chronic Toxicity testing using tropical species. The present work aimed at developing a suitable short-term Chronic Toxicity test with Mysidopsis juniae using zinc (Zn) and nickel (Ni) as model chemicals and growth (length and dry weight), survival, and egg production (number of females with eggs) as endpoints after seven days of exposure. Survival and growth of newborn M. juniae were affected by Chronic exposure to zinc, while nickel affected only survival. For zinc, dry weight was the most sensitive endpoint with significant effects even at the lowest tested concentration (75μgZn·L(-1)), whereas for nickel, survival was the most sensitive parameter (LC20 of 26μgNi·L(-1)). Egg production was not affected. M. juniae short-term Chronic testing is a sensitive approach to evaluating metal Toxicity; further studies are necessary to assess Chronic Toxicity for others contaminants in the proposed assay.

Keith R. Solomon - One of the best experts on this subject based on the ideXlab platform.

  • Chronic Toxicity of the synthetic hormone 17α ethinylestradiol to chironomus tentans and hyalella azteca
    Environmental Toxicology and Chemistry, 2008
    Co-Authors: Keith R. Solomon, Ève B. Dussault, Vimal K. Balakrishnan, Paul K. Sibley
    Abstract:

    The Chronic Toxicity of the synthetic hormone 17α-ethinylestradiol (EE2) was investigated in two benthic invertebrates, the midge Chironomus tentans and the freshwater amphipod Hyalella azteca, in life-cycle water-only assays. In C. tentans, a 50% decrease in emergence was observed at a concentration of 1.5 mg/L; emergence was a more sensitive endpoint than survival, growth, or biomass. Reproduction was not significantly affected by EE2 exposure until a concentration of 3.1 mg/L, where emergence, and therefore reproduction, did not occur. In contrast, reproduction was the most sensitive endpoint in H. azteca (50% decrease in reproduction observed at a concentration of 0.36 mg/L). The sensitivity of the F1 generation to EE2 was also investigated with H. azteca, but was not different from the F0 generation. The data from the present study were combined with those from previous 10-d Toxicity assays, to derive acute to Chronic Toxicity ratios (ACRs) for EE2. The ACRs calculated for EE2 were 13 for C. tentans and 16 for H. azteca, indicating that the application factors currently used in ecological risk assessment for the derivation of Chronic Toxicity are protective and conservative for these organisms. The results of the present study suggest that Chronic Toxicity was not mediated by disruption of endocrine pathways. Using a hazard quotient approach, the risk associated with sublethal exposure to EE2 was << 1 for H. azteca and C. tentans, indicating that adverse effects are not expected, and that environmental exposure to EE2 likely poses a low risk to benthic invertebrates.

  • Chronic Toxicity of the synthetic hormone 17α‐Ethinylestradiol to Chironomus tentans and Hyalella azteca
    Environmental toxicology and chemistry, 2008
    Co-Authors: Ève B. Dussault, Keith R. Solomon, Vimal K. Balakrishnan, Paul K. Sibley
    Abstract:

    The Chronic Toxicity of the synthetic hormone 17α-ethinylestradiol (EE2) was investigated in two benthic invertebrates, the midge Chironomus tentans and the freshwater amphipod Hyalella azteca, in life-cycle water-only assays. In C. tentans, a 50% decrease in emergence was observed at a concentration of 1.5 mg/L; emergence was a more sensitive endpoint than survival, growth, or biomass. Reproduction was not significantly affected by EE2 exposure until a concentration of 3.1 mg/L, where emergence, and therefore reproduction, did not occur. In contrast, reproduction was the most sensitive endpoint in H. azteca (50% decrease in reproduction observed at a concentration of 0.36 mg/L). The sensitivity of the F1 generation to EE2 was also investigated with H. azteca, but was not different from the F0 generation. The data from the present study were combined with those from previous 10-d Toxicity assays, to derive acute to Chronic Toxicity ratios (ACRs) for EE2. The ACRs calculated for EE2 were 13 for C. tentans and 16 for H. azteca, indicating that the application factors currently used in ecological risk assessment for the derivation of Chronic Toxicity are protective and conservative for these organisms. The results of the present study suggest that Chronic Toxicity was not mediated by disruption of endocrine pathways. Using a hazard quotient approach, the risk associated with sublethal exposure to EE2 was

  • Chronic Toxicity of a pure and technical grade pentachlorophenol to Daphnia magna.
    Archives of environmental contamination and toxicology, 1991
    Co-Authors: G. L. Stephenson, N. K. Kaushik, Keith R. Solomon
    Abstract:

    Chronic Toxicity test procedures (static, with renewal) were used to determine the Chronic Toxicity of sublethal concentrations of a technical formulation of pentachlorophenol (PCP) and pure pentachlorophenol toDaphnia magna. Test organisms 48+-12 h old were exposed for their entire lifespan (i.e., until death) to 0.01, 0.05, 0.1 and 0.5 mg technical PCP/L and 0.01, 0.087 and 0.1 mg pure PCP/L. Criteria used to assess Chronic Toxicity were mean time to appearance of the primiparous instar in the brood chamber, mean number of days to release of the first brood, mean number of broods produced per female, mean brood size per female, mean number of reproductive days, mean number of young produced per reproductive day per female and survivorship.

Vimal K. Balakrishnan - One of the best experts on this subject based on the ideXlab platform.

  • Chronic Toxicity of the synthetic hormone 17α ethinylestradiol to chironomus tentans and hyalella azteca
    Environmental Toxicology and Chemistry, 2008
    Co-Authors: Keith R. Solomon, Ève B. Dussault, Vimal K. Balakrishnan, Paul K. Sibley
    Abstract:

    The Chronic Toxicity of the synthetic hormone 17α-ethinylestradiol (EE2) was investigated in two benthic invertebrates, the midge Chironomus tentans and the freshwater amphipod Hyalella azteca, in life-cycle water-only assays. In C. tentans, a 50% decrease in emergence was observed at a concentration of 1.5 mg/L; emergence was a more sensitive endpoint than survival, growth, or biomass. Reproduction was not significantly affected by EE2 exposure until a concentration of 3.1 mg/L, where emergence, and therefore reproduction, did not occur. In contrast, reproduction was the most sensitive endpoint in H. azteca (50% decrease in reproduction observed at a concentration of 0.36 mg/L). The sensitivity of the F1 generation to EE2 was also investigated with H. azteca, but was not different from the F0 generation. The data from the present study were combined with those from previous 10-d Toxicity assays, to derive acute to Chronic Toxicity ratios (ACRs) for EE2. The ACRs calculated for EE2 were 13 for C. tentans and 16 for H. azteca, indicating that the application factors currently used in ecological risk assessment for the derivation of Chronic Toxicity are protective and conservative for these organisms. The results of the present study suggest that Chronic Toxicity was not mediated by disruption of endocrine pathways. Using a hazard quotient approach, the risk associated with sublethal exposure to EE2 was << 1 for H. azteca and C. tentans, indicating that adverse effects are not expected, and that environmental exposure to EE2 likely poses a low risk to benthic invertebrates.

  • Chronic Toxicity of the synthetic hormone 17α‐Ethinylestradiol to Chironomus tentans and Hyalella azteca
    Environmental toxicology and chemistry, 2008
    Co-Authors: Ève B. Dussault, Keith R. Solomon, Vimal K. Balakrishnan, Paul K. Sibley
    Abstract:

    The Chronic Toxicity of the synthetic hormone 17α-ethinylestradiol (EE2) was investigated in two benthic invertebrates, the midge Chironomus tentans and the freshwater amphipod Hyalella azteca, in life-cycle water-only assays. In C. tentans, a 50% decrease in emergence was observed at a concentration of 1.5 mg/L; emergence was a more sensitive endpoint than survival, growth, or biomass. Reproduction was not significantly affected by EE2 exposure until a concentration of 3.1 mg/L, where emergence, and therefore reproduction, did not occur. In contrast, reproduction was the most sensitive endpoint in H. azteca (50% decrease in reproduction observed at a concentration of 0.36 mg/L). The sensitivity of the F1 generation to EE2 was also investigated with H. azteca, but was not different from the F0 generation. The data from the present study were combined with those from previous 10-d Toxicity assays, to derive acute to Chronic Toxicity ratios (ACRs) for EE2. The ACRs calculated for EE2 were 13 for C. tentans and 16 for H. azteca, indicating that the application factors currently used in ecological risk assessment for the derivation of Chronic Toxicity are protective and conservative for these organisms. The results of the present study suggest that Chronic Toxicity was not mediated by disruption of endocrine pathways. Using a hazard quotient approach, the risk associated with sublethal exposure to EE2 was