Fate of Triclosan and Evidence for Reductive Dechlorination of Triclocarban in Estuarine Sediments

Abstract

The biocides triclosan and triclocarban are wastewater contaminants whose occurrence and fate in estuarine sediments remain unexplored. We examined contaminant profiles in 137 Cs/ 7 Be-dated sediment cores taken near wastewater treatment plants in the Chesapeake Bay watershed (CB), Maryland and Jamaica Bay (JB), New York. In JB, biocide occurrences tracked the time course of biocide usage and wastewater treatment strategies employed, first appearing in the 1950s (triclocarban) and 1960s (triclosan), and peaking in the late 1960s and 1970s (24 ± 0.54 and 0.8 ± 0.4 29 mg/kg dry weight, respectively). In CB, where time of sediment accumulation was not as well constrained by 137 Cs depth profiles, triclocarban was only measurable in 137 Cs bearing sediments, peaking at 3.6 ± 0.6 mg/kg midway through the core and exceeding 1 mg/kg in recent deposits. In contrast, triclosan concentrations were low or not detectable in the CB core. Analysis of CB sediment by tandem mass spectrometry produced the first evidence for complete sequential dechlorination of triclocarban to the transformation products dichloro-, monochloro-, and unsubstituted carbanilide which were detected at maxima of 15.5 ± 1.8, 4.1 ± 2.4, and 0.5 ± 0.1 mg/kg, respectively. Concentrations of all carbanilide congeners combined were correlated with heavy metals (R 2 > 0.64, P<0.01), thereby identifying wastewater as the principal pathway of contamination. Environmental persistence over the past 40 years was observed for triclosan and triclocarban in JB, and for triclocarban and its diphenylurea backbone in CB sediments.

Transfer of wastewater associated pharmaceuticals and personal care products to crop plants from biosolids treated soil

“…The background residuals are likely coming from both the aged biosolids and dredge sediment and the biosolids used for application in this experiment. Previously, TCC has been detected in sediment with concentrations varied from 0.7-1.6 mg g À 1 (Miller et al, 2008) and in the biosolids used for application in this study (13.33 mg g À 1 , Wu et al, 2010a). After harvest, the concentrations of CBZ dropped 21.5% and 39.5% in soils with radish and tomato, respectively.…”

Evaluation of triclosan and triclocarban at river basin scale using monitoring and modeling tools: Implications for controlling of urban domestic sewage discharge

“…The weight contents of single TCS or TCC, or both together in the formulas of these products usually range from 0.1% to 2% (Chalew and Halden, 2009). It is reported that the combined annual consumption of TCS and TCC exceeds 600 tons in the United States (Miller et al, 2008), of which TCC usage is estimated to be 227e454 tons (Halden and Paull, 2005). In the European Union, the quantity of TCS used within the region was reported to reach approximately 450 tons for the year 2006 (EC, 2010).…”

Use of a novel sediment exposure to determine the effects of triclosan on estuarine benthic communities

“…In a survey of published studies, triclosan was reported in over 50% of all surface waters with a median concentration of approximately 50 ng/L [3]. It has been found in sediment cores dating back to the mid1960s at concentrations up to 800 mg/kg [4,5]. Concentrations of triclosan are generally higher toward core surfaces, indicating a recent increase in deposition [4,5].…”

“…It has been found in sediment cores dating back to the mid1960s at concentrations up to 800 mg/kg [4,5]. Concentrations of triclosan are generally higher toward core surfaces, indicating a recent increase in deposition [4,5]. In addition to its persistence in sediments, triclosan has been shown to degrade to a dioxin in sunlight [6][7][8].…”