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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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Relation between co-contaminants from a commonsource (A), andparent compound and transformation product (B, C, and D) as plottedthrough their concentrations in sewage sludge from different WWTPs.Each data point represents the average of triplicate measurementsof the analyte concentration in one sewage sludge sample from a WWTP.All data presented in μg/g dry weight.
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fig5: Relation between co-contaminants from a commonsource (A), andparent compound and transformation product (B, C, and D) as plottedthrough their concentrations in sewage sludge from different WWTPs.Each data point represents the average of triplicate measurementsof the analyte concentration in one sewage sludge sample from a WWTP.All data presented in μg/g dry weight.

Mentions: To confirmanticipated relations between certain co-contaminants, correlationanalyses were performed using the average concentrations from individualWWTPs (Figure 5). Hence, a strong relation(Pearson’s r = 0.84) was found between freeTCC and 2′–OH-TCC (Figure 5A),which are both assumed to originate from sewage. To determine whetherTCC dechlorination is driven by the amount of TCC present at the samplinglocation, we examined the data for a correlation between the concentrationsof TCC and DCC. However, no significant correlation was found (Pearson’s r = 0.02) (Figure 5B), suggestingfactors other than TCC concentration as potential determinants, suchas microbial community composition, which was not examined in thiswork. Still, a strong relation between the DCC and MCC levels wasrevealed (Pearson’s r = 0.99) (Figure 5C), suggesting that if TCC dechlorination is initiatedduring standard wastewater treatment, the second step in the dechlorinationof TCC will occur concomitantly, with the formation of MCC likelynot being rate limiting. Thus, other factors (such as microbial communitycomposition or redox conditions) likely are at play in the initiationof TCC dechlorination. Finally, a correlation analysis of TCS andMeTCS was performed to determine whether the levels of TCS in biosolidswere a predictor of the extent of TCS methylation to MeTCS duringstandard wastewater treatment. Levels of TCS in biosolids did notrepresent an adequate predictor for the methylation of TCS (Pearson’s r = 0.01) (Figure 5D), a findingthat is consistent with previous reports.47 Statistical analysis of environmental, geographical, climatic factors,sewage-delivery system or WWTP configuration with plant performancecould not be performed, as release of such information might provideidentifying information.


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)

Relation between co-contaminants from a commonsource (A), andparent compound and transformation product (B, C, and D) as plottedthrough their concentrations in sewage sludge from different WWTPs.Each data point represents the average of triplicate measurementsof the analyte concentration in one sewage sludge sample from a WWTP.All data presented in μg/g dry weight.
© Copyright Policy
Related In: Results  -  Collection

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

fig5: Relation between co-contaminants from a commonsource (A), andparent compound and transformation product (B, C, and D) as plottedthrough their concentrations in sewage sludge from different WWTPs.Each data point represents the average of triplicate measurementsof the analyte concentration in one sewage sludge sample from a WWTP.All data presented in μg/g dry weight.
Mentions: To confirmanticipated relations between certain co-contaminants, correlationanalyses were performed using the average concentrations from individualWWTPs (Figure 5). Hence, a strong relation(Pearson’s r = 0.84) was found between freeTCC and 2′–OH-TCC (Figure 5A),which are both assumed to originate from sewage. To determine whetherTCC dechlorination is driven by the amount of TCC present at the samplinglocation, we examined the data for a correlation between the concentrationsof TCC and DCC. However, no significant correlation was found (Pearson’s r = 0.02) (Figure 5B), suggestingfactors other than TCC concentration as potential determinants, suchas microbial community composition, which was not examined in thiswork. Still, a strong relation between the DCC and MCC levels wasrevealed (Pearson’s r = 0.99) (Figure 5C), suggesting that if TCC dechlorination is initiatedduring standard wastewater treatment, the second step in the dechlorinationof TCC will occur concomitantly, with the formation of MCC likelynot being rate limiting. Thus, other factors (such as microbial communitycomposition or redox conditions) likely are at play in the initiationof TCC dechlorination. Finally, a correlation analysis of TCS andMeTCS was performed to determine whether the levels of TCS in biosolidswere a predictor of the extent of TCS methylation to MeTCS duringstandard wastewater treatment. Levels of TCS in biosolids did notrepresent an adequate predictor for the methylation of TCS (Pearson’s r = 0.01) (Figure 5D), a findingthat is consistent with previous reports.47 Statistical analysis of environmental, geographical, climatic factors,sewage-delivery system or WWTP configuration with plant performancecould not be performed, as release of such information might provideidentifying information.

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