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.
Transformation Products and Human Metabolites of Triclocarban and Triclosan in Sewage Sludge Across the United States
B. Pycke,Isaac B. Roll,B. Brownawell,C. Kinney,E. Furlong,D. Kolpin,R. Halden
Published 2014 in Environmental Science and Technology
ABSTRACT
PUBLICATION RECORD
- Publication year
2014
- Venue
Environmental Science and Technology
- Publication date
2014-06-16
- Fields of study
Medicine, Chemistry, Environmental Science
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
CONCEPTS
- 2'-hydroxy-tcc
A human metabolite of triclocarban detected among the sludge analytes.
Aliases: 2-hydroxy-TCC, 2′-hydroxy-TCC
- anaerobic digestion
A sludge treatment unit operation performed without oxygen.
- dcc-to-tcc ratio
The ratio of dichlorocarbanilide to triclocarban used as an indicator metric in the sludge measurements.
Aliases: DCC/TCC ratio
- dechlorination
A chemical reaction that removes chlorine atoms from a molecule.
- dichlorocarbanilide
A dechlorinated transformation product of triclocarban detected in sewage sludge.
Aliases: DCC
- metcs-to-tcs ratio
The ratio of methyl-triclosan to triclosan used as an indicator metric in the sludge measurements.
Aliases: MeTCS/TCS ratio
- methylation
A chemical reaction that adds a methyl group to a molecule.
- methyl-triclosan
A methylated transformation product of triclosan detected in sewage sludge.
Aliases: MeTCS
- monochlorocarbanilide
A further dechlorinated transformation product of triclocarban detected in sewage sludge.
Aliases: MCC
- sewage conveyance and treatment
The wastewater collection and treatment pathway that sewage passes through before sludge is sampled.
Aliases: sewage conveyance, treatment
- triclocarban
A chlorinated antimicrobial compound abbreviated TCC that was measured in wastewater sludge.
Aliases: TCC
- triclosan
A chlorinated antimicrobial compound abbreviated TCS that was measured in wastewater sludge.
Aliases: TCS
- wastewater treatment plant
A facility that treats municipal wastewater and produces sewage sludge.
Aliases: WWTP
REFERENCES
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