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Transformation products and human metabolites of triclocarban and triclosan in sewage sludge across the United States.

Pycke BF, Roll IB, Brownawell BJ, Kinney CA, Furlong ET, Kolpin DW, Halden RU - Environ. Sci. Technol. (2014)

Bottom Line: Two sample sets were studied: samples collected once from 14 wastewater treatment plants (WWTPs) representing nine states, and multiple samples collected from one WWTP monitored for 12 months.Strong linear correlations were found between TCC and the human metabolite 2'-hydroxy-TCC (r=0.84), and between the TCC-dechlorination products dichlorocarbanilide (DCC) and monochlorocarbanilide (r=0.99).The analysis of sludge sampled before and after different unit operation steps (i.e., anaerobic digestion, sludge heat treatment, and sludge drying) yielded insights into the extent and location of TCC and TCS transformation.

View Article: PubMed Central - PubMed

Affiliation: Center for Environmental Security, Biodesign Institute, Security and Defense Systems Initiative, Arizona State University , 781 East Terrace Road, Tempe, Arizona 85287, United States.

ABSTRACT
Removal of triclocarban (TCC) and triclosan (TCS) from wastewater is a function of adsorption, abiotic degradation, and microbial mineralization or transformation, reactions that are not currently controlled or optimized in the pollution control infrastructure of standard wastewater treatment. Here, we report on the levels of eight transformation products, human metabolites, and manufacturing byproducts of TCC and TCS in raw and treated sewage sludge. Two sample sets were studied: samples collected once from 14 wastewater treatment plants (WWTPs) representing nine states, and multiple samples collected from one WWTP monitored for 12 months. Time-course analysis of significant mass fluxes (α=0.01) indicate that transformation of TCC (dechlorination) and TCS (methylation) occurred during sewage conveyance and treatment. Strong linear correlations were found between TCC and the human metabolite 2'-hydroxy-TCC (r=0.84), and between the TCC-dechlorination products dichlorocarbanilide (DCC) and monochlorocarbanilide (r=0.99). Mass ratios of DCC-to-TCC and of methyl-triclosan (MeTCS)-to-TCS, serving as indicators of transformation activity, revealed that transformation was widespread under different treatment regimes across the WWTPs sampled, though the degree of transformation varied significantly among study sites (α=0.01). The analysis of sludge sampled before and after different unit operation steps (i.e., anaerobic digestion, sludge heat treatment, and sludge drying) yielded insights into the extent and location of TCC and TCS transformation. Results showed anaerobic digestion to be important for MeTCS transformation (37-74%), whereas its contribution to partial TCC dechlorination was limited (0.4-2.1%). This longitudinal and nationwide survey is the first to report the occurrence of transformation products, human metabolites, and manufacturing byproducts of TCC and TCS in sewage sludge.

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Concentrations of TCC, and its microbial (DCC and MCC)and humanmetabolites (2′-OH-TCC and 3′-OH-TCC), and manufacturingbyproducts (DCC and 3′-Cl-TCC), along with those for TCS andthe microbial metabolite MeTCS in biosolids samples from one WWTP(no. 16) sampled during 2009–2010. The error bars representstandard deviations of triplicate extractions calculated from averagesof duplicate injections per sample.
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fig1: Concentrations of TCC, and its microbial (DCC and MCC)and humanmetabolites (2′-OH-TCC and 3′-OH-TCC), and manufacturingbyproducts (DCC and 3′-Cl-TCC), along with those for TCS andthe microbial metabolite MeTCS in biosolids samples from one WWTP(no. 16) sampled during 2009–2010. The error bars representstandard deviations of triplicate extractions calculated from averagesof duplicate injections per sample.

Mentions: The aimof the study was first to determine whether the contaminants occurredin biosolids, and second whether their levels in biosolids grab samplesfrom a single site were consistent during a 12-month period. To achievethese aims, the 10 analytes of interest (SI Figure S1) were monitored for one year using 23 biosolids samplesfrom a single WWTP (no. 16). NCC and 3-CA were not detected in anysample, which left eight principal analytes of interest for this study.As expected for contaminants from a common source, the concentrationchanges were minimal and rarely differed significantly (α =0.01) for the parent compounds, human metabolites, and manufacturingbyproducts (i.e., TCC, 2′-OH-TCC, 3′-OH-TCC, 3′-Cl-TCC,and TCS) over the course of a year as determined using a moving windowanalysis (SI Table S6). The percent changeper time window (n = 22) (typically a two-week period)ranged from 1 to 16% (mean ± standard deviation [x̅] = 7 ± 5%) for TCC, 1–39% (x̅ = 12 ± 11%) for 2′–OH-TCC, 1–132% (x̅ = 31 ± 31%) for 3′–OH-TCC, 1–39%(x̅ = 13 ± 12%) for 3′-Cl-TCC,and 0.4–26% (x̅ = 7 ± 7%) for TCS(Figure 1), where the ranges and averages werecalculated using absolute values of the concentration differences.Conversely, the changes in concentration over different sampling eventswere typically much more pronounced for the transformation productsDCC, MCC, and MeTCS with changes ranging between 4 and 53% (x̅ = 23 ± 14%), 12–180% (x̅ = 54 ± 37%), and 1–800% (x̅ =76 ± 172%), respectively (Figure 1). Themaximum percent change occurred in the same time interval for TCC,2′-OH-TCC, 3′-OH-TCC, and 3′-Cl-TCC (window 13)and in different windows for DCC, MCC, and MeTCS (windows 19, 8, and13, respectively). These findings suggest that the levels of transformationproducts (generated via dechlorination and methylation) in biosolidswas more variable compared to the parent compounds (TCC and TCS),the manufacturing byproduct (3′-Cl-TCC), and the human metabolites(2′-OH-TCC and 3′-OH-TCC), presumably due to fluctuationsin environmental factors (e.g., season, operational parameters, andmicrobial communities). We hypothesized that if indeed transformationis dependent on location-specific environmental factors (e.g., climate/season,population or urban characteristics, sewage system and WWTP design,operational parameters, and microbial communities), then significantdifferences in removal should be observable in biosolids from differentWWTPs across the U.S.


Transformation products and human metabolites of triclocarban and triclosan in sewage sludge across the United States.

Pycke BF, Roll IB, Brownawell BJ, Kinney CA, Furlong ET, Kolpin DW, Halden RU - Environ. Sci. Technol. (2014)

Concentrations of TCC, and its microbial (DCC and MCC)and humanmetabolites (2′-OH-TCC and 3′-OH-TCC), and manufacturingbyproducts (DCC and 3′-Cl-TCC), along with those for TCS andthe microbial metabolite MeTCS in biosolids samples from one WWTP(no. 16) sampled during 2009–2010. The error bars representstandard deviations of triplicate extractions calculated from averagesof duplicate injections per sample.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4215897&req=5

fig1: Concentrations of TCC, and its microbial (DCC and MCC)and humanmetabolites (2′-OH-TCC and 3′-OH-TCC), and manufacturingbyproducts (DCC and 3′-Cl-TCC), along with those for TCS andthe microbial metabolite MeTCS in biosolids samples from one WWTP(no. 16) sampled during 2009–2010. The error bars representstandard deviations of triplicate extractions calculated from averagesof duplicate injections per sample.
Mentions: The aimof the study was first to determine whether the contaminants occurredin biosolids, and second whether their levels in biosolids grab samplesfrom a single site were consistent during a 12-month period. To achievethese aims, the 10 analytes of interest (SI Figure S1) were monitored for one year using 23 biosolids samplesfrom a single WWTP (no. 16). NCC and 3-CA were not detected in anysample, which left eight principal analytes of interest for this study.As expected for contaminants from a common source, the concentrationchanges were minimal and rarely differed significantly (α =0.01) for the parent compounds, human metabolites, and manufacturingbyproducts (i.e., TCC, 2′-OH-TCC, 3′-OH-TCC, 3′-Cl-TCC,and TCS) over the course of a year as determined using a moving windowanalysis (SI Table S6). The percent changeper time window (n = 22) (typically a two-week period)ranged from 1 to 16% (mean ± standard deviation [x̅] = 7 ± 5%) for TCC, 1–39% (x̅ = 12 ± 11%) for 2′–OH-TCC, 1–132% (x̅ = 31 ± 31%) for 3′–OH-TCC, 1–39%(x̅ = 13 ± 12%) for 3′-Cl-TCC,and 0.4–26% (x̅ = 7 ± 7%) for TCS(Figure 1), where the ranges and averages werecalculated using absolute values of the concentration differences.Conversely, the changes in concentration over different sampling eventswere typically much more pronounced for the transformation productsDCC, MCC, and MeTCS with changes ranging between 4 and 53% (x̅ = 23 ± 14%), 12–180% (x̅ = 54 ± 37%), and 1–800% (x̅ =76 ± 172%), respectively (Figure 1). Themaximum percent change occurred in the same time interval for TCC,2′-OH-TCC, 3′-OH-TCC, and 3′-Cl-TCC (window 13)and in different windows for DCC, MCC, and MeTCS (windows 19, 8, and13, respectively). These findings suggest that the levels of transformationproducts (generated via dechlorination and methylation) in biosolidswas more variable compared to the parent compounds (TCC and TCS),the manufacturing byproduct (3′-Cl-TCC), and the human metabolites(2′-OH-TCC and 3′-OH-TCC), presumably due to fluctuationsin environmental factors (e.g., season, operational parameters, andmicrobial communities). We hypothesized that if indeed transformationis dependent on location-specific environmental factors (e.g., climate/season,population or urban characteristics, sewage system and WWTP design,operational parameters, and microbial communities), then significantdifferences in removal should be observable in biosolids from differentWWTPs across the U.S.

Bottom Line: Two sample sets were studied: samples collected once from 14 wastewater treatment plants (WWTPs) representing nine states, and multiple samples collected from one WWTP monitored for 12 months.Strong linear correlations were found between TCC and the human metabolite 2'-hydroxy-TCC (r=0.84), and between the TCC-dechlorination products dichlorocarbanilide (DCC) and monochlorocarbanilide (r=0.99).The analysis of sludge sampled before and after different unit operation steps (i.e., anaerobic digestion, sludge heat treatment, and sludge drying) yielded insights into the extent and location of TCC and TCS transformation.

View Article: PubMed Central - PubMed

Affiliation: Center for Environmental Security, Biodesign Institute, Security and Defense Systems Initiative, Arizona State University , 781 East Terrace Road, Tempe, Arizona 85287, United States.

ABSTRACT
Removal of triclocarban (TCC) and triclosan (TCS) from wastewater is a function of adsorption, abiotic degradation, and microbial mineralization or transformation, reactions that are not currently controlled or optimized in the pollution control infrastructure of standard wastewater treatment. Here, we report on the levels of eight transformation products, human metabolites, and manufacturing byproducts of TCC and TCS in raw and treated sewage sludge. Two sample sets were studied: samples collected once from 14 wastewater treatment plants (WWTPs) representing nine states, and multiple samples collected from one WWTP monitored for 12 months. Time-course analysis of significant mass fluxes (α=0.01) indicate that transformation of TCC (dechlorination) and TCS (methylation) occurred during sewage conveyance and treatment. Strong linear correlations were found between TCC and the human metabolite 2'-hydroxy-TCC (r=0.84), and between the TCC-dechlorination products dichlorocarbanilide (DCC) and monochlorocarbanilide (r=0.99). Mass ratios of DCC-to-TCC and of methyl-triclosan (MeTCS)-to-TCS, serving as indicators of transformation activity, revealed that transformation was widespread under different treatment regimes across the WWTPs sampled, though the degree of transformation varied significantly among study sites (α=0.01). The analysis of sludge sampled before and after different unit operation steps (i.e., anaerobic digestion, sludge heat treatment, and sludge drying) yielded insights into the extent and location of TCC and TCS transformation. Results showed anaerobic digestion to be important for MeTCS transformation (37-74%), whereas its contribution to partial TCC dechlorination was limited (0.4-2.1%). This longitudinal and nationwide survey is the first to report the occurrence of transformation products, human metabolites, and manufacturing byproducts of TCC and TCS in sewage sludge.

Show MeSH
Related in: MedlinePlus