The Experts below are selected from a list of 10476 Experts worldwide ranked by ideXlab platform
Hungsuck Park - One of the best experts on this subject based on the ideXlab platform.
-
sorption of Triclosan onto activated carbon kaolinite and montmorillonite effects of ph ionic strength and humic acid
Journal of Hazardous Materials, 2010Co-Authors: Shishir Kumar Behera, Hungsuck ParkAbstract:Abstract Sorption of Triclosan on three sorbents, viz., activated carbon, kaolinite and montmorillonite was studied as a function of pH, ionic strength and humic acid (HA) concentration through controlled batch experiments. Triclosan sorption was found to be higher in the acidic pH range, as varying pH showed significant influence on the surface charge of the sorbents and degree of ionization of the sorbate. Sorption capacity of the sorbents increased with an increase in the ionic strength of solution. At low pH (pH 3), the overall increase in Triclosan sorption was 1.2, ∼4 and 3.5 times, respectively for activated carbon, kaolinite and montmorillonite when ionic strength was increased from 1 × 10 −3 to 5 × 10 −1 M. Triclosan sorption onto activated carbon decreased from 31.4 to 10.6 mg g −1 by increasing the HA concentration to 200 mg C L −1 . However, during sorption onto kaolinite and montmorillonite, the effect of HA was very complex probably due to (i) hydrophobicity (log K ow = 4.76) of Triclosan; and (ii) complexation of HA with Triclosan. Though Triclosan sorption onto activated carbon is higher, the potential of kaolinite and montmorillonite in controlling the transport of Triclosan in subsurface environment can still be appreciable.
-
sorption of Triclosan onto activated carbon kaolinite and montmorillonite effects of ph ionic strength and humic acid
Journal of Hazardous Materials, 2010Co-Authors: Shishir Kumar Behera, Hungsuck ParkAbstract:Sorption of Triclosan on three sorbents, viz., activated carbon, kaolinite and montmorillonite was studied as a function of pH, ionic strength and humic acid (HA) concentration through controlled batch experiments. Triclosan sorption was found to be higher in the acidic pH range, as varying pH showed significant influence on the surface charge of the sorbents and degree of ionization of the sorbate. Sorption capacity of the sorbents increased with an increase in the ionic strength of solution. At low pH (pH 3), the overall increase in Triclosan sorption was 1.2, approximately 4 and 3.5 times, respectively for activated carbon, kaolinite and montmorillonite when ionic strength was increased from 1x10(-3) to 5x10(-1) M. Triclosan sorption onto activated carbon decreased from 31.4 to 10.6 mg g(-1) by increasing the HA concentration to 200 mg C L(-1). However, during sorption onto kaolinite and montmorillonite, the effect of HA was very complex probably due to (i) hydrophobicity (log K(ow)=4.76) of Triclosan; and (ii) complexation of HA with Triclosan. Though Triclosan sorption onto activated carbon is higher, the potential of kaolinite and montmorillonite in controlling the transport of Triclosan in subsurface environment can still be appreciable.
Leah M Zorrilla - One of the best experts on this subject based on the ideXlab platform.
-
Triclosan exposure modulates estrogen dependent responses in the female wistar rat
Toxicological Sciences, 2010Co-Authors: Tammy E Stoker, Emily K. Gibson, Leah M ZorrillaAbstract:Triclosan is an antimicrobial found in personal care and sanitizing products, such as soaps, toothpaste, and hair products. There have been recent concerns for the possible effects on human health, as Triclosan has been detected in human breast milk, blood, and urine samples. In a previous study, we found that Triclosan alters serum thyroid hormone and testosterone concentrations in male rats. In the current study, we evaluated the effects of Triclosan in the female Wistar rat following exposure for 21 days in the Endocrine Disruptor Screening Program pubertal protocol and the weanling uterotrophic assay (3-day exposure). In the pubertal study, Triclosan advanced the age of onset of vaginal opening and increased uterine weight at 150 mg/kg, indicative of an estrogenic effect. In the uterotrophic assay, rats received oral doses of Triclosan (1.18, 2.35, 4.69, 9.37, 18.75, 37.5, 75, 150, and 300 mg/kg) alone, 3 mg/kg ethinyl estradiol (EE), or Triclosan (same doses as above) plus 3 mg/kg EE. Uterine weight was increased in the EE group (positive control) as compared with the control but was not affected by Triclosan alone. However, there was a significant dose-dependent increase in the group cotreated with EE and Triclosan (‡ 4.69 mg/kg) as compared with EE alone, indicating a potentiation of the estrogen response on uterine weight. This result was well correlated with potentiated estrogeninduced changes in uterine histology. Serum thyroid hormone concentrations were also suppressed by Triclosan in this study, similar to other studies in the male and female rat. In conclusion, Triclosan affected estrogen-mediated responses in the pubertal and weanling female rat and also suppressed thyroid hormone in both studies. The lowest effective concentrations in the rodent model are ~10 (for estrogen) and 40 (for thyroid hormone) times higher than the highest concentrations reported in human plasma.
-
Triclosan exposure modulates estrogen dependent responses in the female wistar rat
Toxicological Sciences, 2010Co-Authors: Tammy E Stoker, Emily K. Gibson, Leah M ZorrillaAbstract:Triclosan is an antimicrobial found in personal care and sanitizing products, such as soaps, toothpaste, and hair products. There have been recent concerns for the possible effects on human health, as Triclosan has been detected in human breast milk, blood, and urine samples. In a previous study, we found that Triclosan alters serum thyroid hormone and testosterone concentrations in male rats. In the current study, we evaluated the effects of Triclosan in the female Wistar rat following exposure for 21 days in the Endocrine Disruptor Screening Program pubertal protocol and the weanling uterotrophic assay (3-day exposure). In the pubertal study, Triclosan advanced the age of onset of vaginal opening and increased uterine weight at 150 mg/kg, indicative of an estrogenic effect. In the uterotrophic assay, rats received oral doses of Triclosan (1.18, 2.35, 4.69, 9.37, 18.75, 37.5, 75, 150, and 300 mg/kg) alone, 3 microg/kg ethinyl estradiol (EE), or Triclosan (same doses as above) plus 3 microg/kg EE. Uterine weight was increased in the EE group (positive control) as compared with the control but was not affected by Triclosan alone. However, there was a significant dose-dependent increase in the group cotreated with EE and Triclosan (>or= 4.69 mg/kg) as compared with EE alone, indicating a potentiation of the estrogen response on uterine weight. This result was well correlated with potentiated estrogen-induced changes in uterine histology. Serum thyroid hormone concentrations were also suppressed by Triclosan in this study, similar to other studies in the male and female rat. In conclusion, Triclosan affected estrogen-mediated responses in the pubertal and weanling female rat and also suppressed thyroid hormone in both studies. The lowest effective concentrations in the rodent model are approximately 10 (for estrogen) and 40 (for thyroid hormone) times higher than the highest concentrations reported in human plasma.
Caren C Helbing - One of the best experts on this subject based on the ideXlab platform.
-
the bactericidal agent Triclosan modulates thyroid hormone associated gene expression and disrupts postembryonic anuran development
Aquatic Toxicology, 2006Co-Authors: Nik Veldhoen, Rachel C Skirrow, Heather L Osachoff, Heidi Wigmore, David J Clapson, Mark P Gunderson, Graham Van Aggelen, Caren C HelbingAbstract:We investigated whether exposure to environmentally relevant concentrations of the bactericidal agent, Triclosan, induces changes in the thyroid hormone-mediated process of metamorphosis of the North American bullfrog, Rana catesbeiana and alters the expression profile of thyroid hormone receptor (TR) alpha and beta, basic transcription element binding protein (BTEB) and proliferating nuclear cell antigen (PCNA) gene transcripts. Premetamorphic tadpoles were immersed in environmentally relevant concentrations of Triclosan and injected with 1 x 10(-11)mol/g body weight 3,5,3'-triiodothyronine (T3) or vehicle control. Morphometric measurements and steady-state mRNA levels obtained by quantitative polymerase chain reaction were determined. mRNA abundance was also examined in Xenopus laevis XTC-2 cells treated with Triclosan and/or 10nM T3. Tadpoles pretreated with Triclosan concentrations as low as 0.15+/-0.03 microg/L for 4 days showed increased hindlimb development and a decrease in total body weight following T3 administration. Triclosan exposure also resulted in decreased T3-mediated TRbeta mRNA expression in the tadpole tail fin and increased levels of PCNA transcript in the brain within 48 h of T3 treatment whereas TRalpha was unaffected [corrected] Triclosan alone altered thyroid hormone receptor alpha transcript levels in the brain of premetamorphic tadpoles and induced a transient weight loss. In XTC-2 cells, exposure to T3 plus nominal concentrations of Triclosan as low as 0.03 microg/L for 24h resulted in altered thyroid hormone receptor mRNA expression. Exposure to low levels of Triclosan disrupts thyroid hormone-associated gene expression and can alter the rate of thyroid hormone-mediated postembryonic anuran development.
-
the bactericidal agent Triclosan modulates thyroid hormone associated gene expression and disrupts postembryonic anuran development
Aquatic Toxicology, 2006Co-Authors: Nik Veldhoen, Rachel C Skirrow, Heather L Osachoff, Heidi Wigmore, David J Clapson, Mark P Gunderson, Graham Van Aggelen, Caren C HelbingAbstract:Abstract We investigated whether exposure to environmentally relevant concentrations of the bactericidal agent, Triclosan, induces changes in the thyroid hormone-mediated process of metamorphosis of the North American bullfrog, Rana catesbeiana and alters the expression profile of thyroid hormone receptor (TR) α and β, basic transcription element binding protein (BTEB) and proliferating nuclear cell antigen (PCNA) gene transcripts. Premetamorphic tadpoles were immersed in environmentally relevant concentrations of Triclosan and injected with 1 × 10 −11 mol/g body weight 3,5,3′-triiodothyronine (T 3 ) or vehicle control. Morphometric measurements and steady-state mRNA levels obtained by quantitative polymerase chain reaction were determined. mRNA abundance was also examined in Xenopus laevis XTC-2 cells treated with Triclosan and/or 10 nM T 3 . Tadpoles pretreated with Triclosan concentrations as low as 0.15 ± 0.03 μg/L for 4 days showed increased hindlimb development and a decrease in total body weight following T 3 administration. Triclosan exposure also resulted in decreased T 3 -mediated TRβ mRNA expression in the tadpole tail fin and increased levels of PCNA transcript in the brain within 48 h of T 3 treatment whereas TRα and BTEB were unaffected. Triclosan alone altered thyroid hormone receptor α transcript levels in the brain of premetamorphic tadpoles and induced a transient weight loss. In XTC-2 cells, exposure to T 3 plus nominal concentrations of Triclosan as low as 0.03 μg/L for 24 h resulted in altered thyroid hormone receptor mRNA expression. Exposure to low levels of Triclosan disrupts thyroid hormone-associated gene expression and can alter the rate of thyroid hormone-mediated postembryonic anuran development.
Shishir Kumar Behera - One of the best experts on this subject based on the ideXlab platform.
-
sorption of Triclosan onto activated carbon kaolinite and montmorillonite effects of ph ionic strength and humic acid
Journal of Hazardous Materials, 2010Co-Authors: Shishir Kumar Behera, Hungsuck ParkAbstract:Abstract Sorption of Triclosan on three sorbents, viz., activated carbon, kaolinite and montmorillonite was studied as a function of pH, ionic strength and humic acid (HA) concentration through controlled batch experiments. Triclosan sorption was found to be higher in the acidic pH range, as varying pH showed significant influence on the surface charge of the sorbents and degree of ionization of the sorbate. Sorption capacity of the sorbents increased with an increase in the ionic strength of solution. At low pH (pH 3), the overall increase in Triclosan sorption was 1.2, ∼4 and 3.5 times, respectively for activated carbon, kaolinite and montmorillonite when ionic strength was increased from 1 × 10 −3 to 5 × 10 −1 M. Triclosan sorption onto activated carbon decreased from 31.4 to 10.6 mg g −1 by increasing the HA concentration to 200 mg C L −1 . However, during sorption onto kaolinite and montmorillonite, the effect of HA was very complex probably due to (i) hydrophobicity (log K ow = 4.76) of Triclosan; and (ii) complexation of HA with Triclosan. Though Triclosan sorption onto activated carbon is higher, the potential of kaolinite and montmorillonite in controlling the transport of Triclosan in subsurface environment can still be appreciable.
-
sorption of Triclosan onto activated carbon kaolinite and montmorillonite effects of ph ionic strength and humic acid
Journal of Hazardous Materials, 2010Co-Authors: Shishir Kumar Behera, Hungsuck ParkAbstract:Sorption of Triclosan on three sorbents, viz., activated carbon, kaolinite and montmorillonite was studied as a function of pH, ionic strength and humic acid (HA) concentration through controlled batch experiments. Triclosan sorption was found to be higher in the acidic pH range, as varying pH showed significant influence on the surface charge of the sorbents and degree of ionization of the sorbate. Sorption capacity of the sorbents increased with an increase in the ionic strength of solution. At low pH (pH 3), the overall increase in Triclosan sorption was 1.2, approximately 4 and 3.5 times, respectively for activated carbon, kaolinite and montmorillonite when ionic strength was increased from 1x10(-3) to 5x10(-1) M. Triclosan sorption onto activated carbon decreased from 31.4 to 10.6 mg g(-1) by increasing the HA concentration to 200 mg C L(-1). However, during sorption onto kaolinite and montmorillonite, the effect of HA was very complex probably due to (i) hydrophobicity (log K(ow)=4.76) of Triclosan; and (ii) complexation of HA with Triclosan. Though Triclosan sorption onto activated carbon is higher, the potential of kaolinite and montmorillonite in controlling the transport of Triclosan in subsurface environment can still be appreciable.
Tammy E Stoker - One of the best experts on this subject based on the ideXlab platform.
-
Triclosan exposure modulates estrogen dependent responses in the female wistar rat
Toxicological Sciences, 2010Co-Authors: Tammy E Stoker, Emily K. Gibson, Leah M ZorrillaAbstract:Triclosan is an antimicrobial found in personal care and sanitizing products, such as soaps, toothpaste, and hair products. There have been recent concerns for the possible effects on human health, as Triclosan has been detected in human breast milk, blood, and urine samples. In a previous study, we found that Triclosan alters serum thyroid hormone and testosterone concentrations in male rats. In the current study, we evaluated the effects of Triclosan in the female Wistar rat following exposure for 21 days in the Endocrine Disruptor Screening Program pubertal protocol and the weanling uterotrophic assay (3-day exposure). In the pubertal study, Triclosan advanced the age of onset of vaginal opening and increased uterine weight at 150 mg/kg, indicative of an estrogenic effect. In the uterotrophic assay, rats received oral doses of Triclosan (1.18, 2.35, 4.69, 9.37, 18.75, 37.5, 75, 150, and 300 mg/kg) alone, 3 microg/kg ethinyl estradiol (EE), or Triclosan (same doses as above) plus 3 microg/kg EE. Uterine weight was increased in the EE group (positive control) as compared with the control but was not affected by Triclosan alone. However, there was a significant dose-dependent increase in the group cotreated with EE and Triclosan (>or= 4.69 mg/kg) as compared with EE alone, indicating a potentiation of the estrogen response on uterine weight. This result was well correlated with potentiated estrogen-induced changes in uterine histology. Serum thyroid hormone concentrations were also suppressed by Triclosan in this study, similar to other studies in the male and female rat. In conclusion, Triclosan affected estrogen-mediated responses in the pubertal and weanling female rat and also suppressed thyroid hormone in both studies. The lowest effective concentrations in the rodent model are approximately 10 (for estrogen) and 40 (for thyroid hormone) times higher than the highest concentrations reported in human plasma.
-
Triclosan exposure modulates estrogen dependent responses in the female wistar rat
Toxicological Sciences, 2010Co-Authors: Tammy E Stoker, Emily K. Gibson, Leah M ZorrillaAbstract:Triclosan is an antimicrobial found in personal care and sanitizing products, such as soaps, toothpaste, and hair products. There have been recent concerns for the possible effects on human health, as Triclosan has been detected in human breast milk, blood, and urine samples. In a previous study, we found that Triclosan alters serum thyroid hormone and testosterone concentrations in male rats. In the current study, we evaluated the effects of Triclosan in the female Wistar rat following exposure for 21 days in the Endocrine Disruptor Screening Program pubertal protocol and the weanling uterotrophic assay (3-day exposure). In the pubertal study, Triclosan advanced the age of onset of vaginal opening and increased uterine weight at 150 mg/kg, indicative of an estrogenic effect. In the uterotrophic assay, rats received oral doses of Triclosan (1.18, 2.35, 4.69, 9.37, 18.75, 37.5, 75, 150, and 300 mg/kg) alone, 3 mg/kg ethinyl estradiol (EE), or Triclosan (same doses as above) plus 3 mg/kg EE. Uterine weight was increased in the EE group (positive control) as compared with the control but was not affected by Triclosan alone. However, there was a significant dose-dependent increase in the group cotreated with EE and Triclosan (‡ 4.69 mg/kg) as compared with EE alone, indicating a potentiation of the estrogen response on uterine weight. This result was well correlated with potentiated estrogeninduced changes in uterine histology. Serum thyroid hormone concentrations were also suppressed by Triclosan in this study, similar to other studies in the male and female rat. In conclusion, Triclosan affected estrogen-mediated responses in the pubertal and weanling female rat and also suppressed thyroid hormone in both studies. The lowest effective concentrations in the rodent model are ~10 (for estrogen) and 40 (for thyroid hormone) times higher than the highest concentrations reported in human plasma.
-
The effects of Triclosan on puberty and thyroid hormones in male wistar rats
Toxicological Sciences, 2009Co-Authors: L.m. Zorrilla, Emily K. Gibson, Susan C. Jeffay, Ralph L. Cooper, Woodrow R Setzer, Kevin M. Crofton, Tammy E StokerAbstract:Triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) is a potent antibacterial and antifungal compound that is widely used in personal care products, plastics, and fabrics. Recently Triclosan has been shown to alter endocrine function in a variety of species. The purpose of this study was to determine effects of Triclosan on pubertal development and thyroid hormone concentrations in the male rat. Weanling rats were exposed to 0, 3, 30, 100, 200, or 300 mg/kg of Triclosan by oral gavage from postnatal day (PND) 23 to 53. Preputial separation (PPS) was examined beginning on PND 33. Rats were killed on PND 53, organ weights were recorded and serum was collected for subsequent analysis. Triclosan did not affect growth or the onset of PPS. Serum testosterone was significantly decreased at 200 mg/kg, however no effects were observed on androgen-dependent reproductive tissue weights. Triclosan significantly decreased total serum thyroxine (T4) in a dose-dependent manner at 30 mg/kg and higher (no observed effect level of 3 mg/kg). Triiodothyronine (T3) was significantly decreased only at 200 mg/kg, but thyroid stimulating hormone was not statistically different at any dose. Liver weights were significantly increased at 100 mg/kg Triclosan and above suggesting that the induction of hepatic enzymes may have contributed to the altered T4 and T3 concentrations, but it does not appear to correlate with the T4 dose-response. This study demonstrates that Triclosan exposure does not alter androgen-dependent tissue weights or onset of PPS; however, Triclosan exposure significantly impacts thyroid hormone concentrations in the male juvenile rat.
