The fate and effects of Triclosan in the lower Hudson River estuary

This study examined the dispersal, fate and ecological effects of Triclosan in the lower Hudson River estuary. Four major concerns regarding this compound were assessed; (1) the overall accumulation and degradation of Triclosan within estuarine sediments; (2) the correlation between Triclosan with carbon (organic and inorganic); (3) the factors determining the overall distribution and concentration of Triclosan throughout the estuary; and (4) the potential toxicological effects of Triclosan on estuarine micro-organisms.;Triclosan concentrations in sediments from the lower Hudson River estuary ranged from 2-88 ng/g. The vertical profile of Triclosan in a one-meter sediment vibracore (dated using Cesium-137) indicated that Triclosan has been preserved in sediments dating back to the mid 1960's, when it was first released. In addition, there is limited evidence of a negative correlation between the concentrations of Triclosan and organic carbon with no evidence of a correlation between inorganic carbon and Triclosan. This lack of correlation between Triclosan and carbon may reflect the relative uniform organic and inorganic carbon concentrations measured in the sediment cores collected throughout the estuary, and variations in Triclosan's input function via CSOs and treated wastewater discharges.;The average water column concentration of Triclosan for the lower Hudson River estuary is 3+/-2 ng/1 and is consistent with a dilution of average wastewater concentrations with freshwater and seawater. The empirically derived partitioning coefficient (using average sediment concentrations of 26+/-11 ng/g) for Triclosan the kd ∼ 104, which is similar to theoretical and laboratory estimates of the kd. Photodegradation and biological uptake should be evaluated on a site by site basis.;This study demonstrates that the current concentration aqueous and particulate bound Triclosan do not pose a risk to natural communities in the lower estuary. However, chlorophyll a concentrations in algal communities were significantly reduced by 20--30% when phytoplankton were exposed to 20 and 200 ng/g concentrations of aqueous Triclosan for 12--24 h (p < 0.05). Additionally the estimated effective concentration (EC50 ) for laboratory bacteria exposed to aqueous Triclosan for less than 1 hour is 13 ng/l. There was no effect, however, from acutely exposing bacteria to particulate-bound Triclosan (15--34 ng/g).