Temporal trends of triclosan contamination in dated sediment cores from four urbanized estuaries: Evidence of preservation and accumulation

Triclosan is an antimicrobial agent added to a wide array of consumer goods and personal care products. Through its use, it is introduced into municipal sewer systems where it is only partially removed during wastewater treatment. In this study, triclosan was measured in dated sediment cores from four urbanized estuaries in order to reconstruct temporal and spatial trends of accumulation. Measurable concentrations of triclosan first appeared in each of the sediment cores near 1964, which corresponds with the US patent issuance date of triclosan. The presence of triclosan at each of the study sites at or near the patent date indicates that long-term preservation is occurring in estuarine sediments. Temporal trends of triclosan at each location are unique, reflecting between site variability. Concentrations at one site climbed to as high as 400 ng g−1, due in part, to local commercial production of triclosan. At two locations, levels of triclosan rise towards the surface of each core, suggesting increasing usage in recent years.One location adjacent to a major combined sewer overflow had high sediment concentrations of triclosan, confirming their potential as a source of triclosan to estuaries.