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Factors Regulating the Accumulation and Spatial Distribution of the Emerging Contaminant Triclosan in the Sediments of an Urbanized Estuary: Greenwich Bay, Rhode Island, USA
Citation:
KATZ, D. R., M. G. CANTWELL, J. C. SULLIVAN, M. M. PERRON, R. M. BURGESS, K. T. HO, AND M. A. CHARPENTIER. Factors Regulating the Accumulation and Spatial Distribution of the Emerging Contaminant Triclosan in the Sediments of an Urbanized Estuary: Greenwich Bay, Rhode Island, USA. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 443:123-133, (2013).
Impact/Purpose:
Triclosan is an antibacterial additive used in the formulation of a variety of consumer and personal care products. Triclosan’s primary route of entry to the environment is through domestic wastewater treatment plant discharges. Triclosan has been identified as a contaminant of emerging concern, with little known about its fate and effects, particularly in estuarine environments. This manuscript describes the spatial distribution of Triclosan in surficial sediments and a sediment core collected from a semi-enclosed urbanized estuarine embayment located within Narragansett Bay, Rhode Island on the Atlantic Coast of the United States. Surficial sediments show a decrease in Triclosan concentrations with increasing distance from the waste water treatment plant. Previous sediment core records typically show increasing Triclosan concentrations over the last several decades, however, sediment core data from this site shows a decrease in Triclosan over approximately the last 20 years. The decrease in Triclosan upcore also corresponds to a contemporaneous decrease of a chemical tracer associated with local commercial production of Triclosan. An estimate of the spatial distribution of Triclosan was produced using ordinary kriging, and these results combined with waste water treatment effluent data indicate Triclosan is being advected into Greenwich Bay from outside sources. The information in this article will be useful for scientists and regulators involved with assessing the environmental risk associated with the use of Triclosan and similar chemicals used in consumer products which enter the environment via waste water treatment effluent.
Description:
Increase in the use of personal care products (PCPs) has resulted in the release and accumulation of a diverse assemblage of emerging chemicals in the environment. Triclosan (TCS) is an antimicrobial compound being increasingly used in PCPs over the last 40 years, and as a result is present in wastewater treatment plant (WWTP) effluents. Widespread domestic use has resulted in environmental discharge of TCS, whose ecological consequences, especially in the marine environment, are poorly understood. Continuous discharge of wastewater effluent has resulted in the accumulation of PCPs such as TCS in coastal and estuarine sediments. The present study investigated whether WWTP effluent is the primary source of TCS within a small urbanized estuarine embayment that is supplied by a single domestic WWTP. Greenwich Bay, located within Narragansett Bay (RI, USA) contained dissolved water column TCS ranging between 0.5 and 7.4 ng L-1, and surficial sediment concentrations ranging between 3 to 32 ng g-1. Despite predictions, spatial distributions of TCS were not related to proximity to the WWTP outfall. Further, a Greenwich Bay-wide sediment TCS budget, estimated by spatial interpolation, suggested that annual accumulation rates exceeded the calculated annual discharge of TCS from the local WWTP. Contributors of TCS to Greenwich Bay include advection from upper Narragansett Bay, which receives effluent from several large WWTPs and contains TCS-contaminated sediments from past manufacturing activities. This study provides evidence that WWTP effluent is an important source of TCS and likely for other PCPs. It also demonstrates that WWTP systems are important controls to mitigate environmental discharge of TCS and that TCS is sufficiently persistent in the environment. As a result, distant as well as local WWTP sources should be accounted for when considering management actions to limit environmental TCS and other widely used PCPs.