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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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Related in: MedlinePlus

Box-and-whisker plotof the contaminant concentrations in biosolidsfrom 14 locations from nine states across the United States (thisstudy) respective to the TCC and TCS levels measured previously (i.e.,shaded boxplots) in biosolids sampled during the 2001 U.S. EPA NationalSewage Sludge Survey (“TCC(’01)” and “TCS(’01)”).59
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fig2: Box-and-whisker plotof the contaminant concentrations in biosolidsfrom 14 locations from nine states across the United States (thisstudy) respective to the TCC and TCS levels measured previously (i.e.,shaded boxplots) in biosolids sampled during the 2001 U.S. EPA NationalSewage Sludge Survey (“TCC(’01)” and “TCS(’01)”).59

Mentions: To assesswhether the transformation of TCC and TCS is site-dependent, sewagesludge and biosolids samples from 14 different WWTPs from across theUnited States were screened for TCS, TCC, their transformation products,human metabolites, and manufacturing byproducts. Figure 2 summarizes the distribution of average biosolids concentrationsfrom these 14 different WWTPs. Data for 3′-OH-TCC is not shownbecause this chemical was detected only very rarely (at two sitesonly). When investigating for transformation of TCC and TCS, massspectrometric analysis revealed that there were significant differences(α = 0.05) in the extent of dechlorination of TCC and methylationof TCS between samples from different WWTPs. The measure chosen toassess removal of TCC was the DCC/TCC ratio. Technical-grade TCC (>99%),which is commonly used in commercial applications, has a DCC-to-TCCratio of about 0.002.45 Under the assumptionthat TCC dechlorination rates are slow during wastewater treatment,an increase in the DCC/TCC ratio from the 0.002 base value may beindicative of (incomplete) removal of TCC. We found that the DCC/TCCratio in biosolids increased significantly at most locations, varyingfrom about 0.001 ± 0.000 to 0.901 ± 0.013 in the WWTP samples(Figure 3), suggesting that the initiationof TCC dechlorination was widespread. Yet, because NCC was never detected,it remains unclear whether TCC dechlorination was indeed slow andincomplete (with no NCC formation), or whether NCC was readily degradedand thus complete dechlorination of TCC may have occurred during wastewatertreatment. The samples were also screened for 3-CA, an abiotic transformationproduct of TCC, DCC, and MCC but that compound was not detected; lackof detection could be due to absence of 3-CA in the sample or lackof partitioning into sludge used for analysis. The TCC transformationefficiency was found to be unrelated to that of TCS, since no relationshipwas found between the observed DCC/TCC and MeTCS/TCS ratios (Figure 3); the latter being the measure chosen to assesstransformation of TCS. In fact, one of the WWTPs where no DCC wasdetected (B9) had one of the highest MeTCS/TCS ratios (0.215 ±0.020). Determination of less chlorinated triclosan derivatives wasnot performed because of the absence of commercially available authenticstandards for identification and quantification.


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)

Box-and-whisker plotof the contaminant concentrations in biosolidsfrom 14 locations from nine states across the United States (thisstudy) respective to the TCC and TCS levels measured previously (i.e.,shaded boxplots) in biosolids sampled during the 2001 U.S. EPA NationalSewage Sludge Survey (“TCC(’01)” and “TCS(’01)”).59
© Copyright Policy
Related In: Results  -  Collection

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

fig2: Box-and-whisker plotof the contaminant concentrations in biosolidsfrom 14 locations from nine states across the United States (thisstudy) respective to the TCC and TCS levels measured previously (i.e.,shaded boxplots) in biosolids sampled during the 2001 U.S. EPA NationalSewage Sludge Survey (“TCC(’01)” and “TCS(’01)”).59
Mentions: To assesswhether the transformation of TCC and TCS is site-dependent, sewagesludge and biosolids samples from 14 different WWTPs from across theUnited States were screened for TCS, TCC, their transformation products,human metabolites, and manufacturing byproducts. Figure 2 summarizes the distribution of average biosolids concentrationsfrom these 14 different WWTPs. Data for 3′-OH-TCC is not shownbecause this chemical was detected only very rarely (at two sitesonly). When investigating for transformation of TCC and TCS, massspectrometric analysis revealed that there were significant differences(α = 0.05) in the extent of dechlorination of TCC and methylationof TCS between samples from different WWTPs. The measure chosen toassess removal of TCC was the DCC/TCC ratio. Technical-grade TCC (>99%),which is commonly used in commercial applications, has a DCC-to-TCCratio of about 0.002.45 Under the assumptionthat TCC dechlorination rates are slow during wastewater treatment,an increase in the DCC/TCC ratio from the 0.002 base value may beindicative of (incomplete) removal of TCC. We found that the DCC/TCCratio in biosolids increased significantly at most locations, varyingfrom about 0.001 ± 0.000 to 0.901 ± 0.013 in the WWTP samples(Figure 3), suggesting that the initiationof TCC dechlorination was widespread. Yet, because NCC was never detected,it remains unclear whether TCC dechlorination was indeed slow andincomplete (with no NCC formation), or whether NCC was readily degradedand thus complete dechlorination of TCC may have occurred during wastewatertreatment. The samples were also screened for 3-CA, an abiotic transformationproduct of TCC, DCC, and MCC but that compound was not detected; lackof detection could be due to absence of 3-CA in the sample or lackof partitioning into sludge used for analysis. The TCC transformationefficiency was found to be unrelated to that of TCS, since no relationshipwas found between the observed DCC/TCC and MeTCS/TCS ratios (Figure 3); the latter being the measure chosen to assesstransformation of TCS. In fact, one of the WWTPs where no DCC wasdetected (B9) had one of the highest MeTCS/TCS ratios (0.215 ±0.020). Determination of less chlorinated triclosan derivatives wasnot performed because of the absence of commercially available authenticstandards for identification and quantification.

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