Abstract
The rigin and fate of six phthalate esters (dimethyl phthalate (DMP), diethyl phthalate (DEP), di‐n‐butyl phthalate (DnBP), butyl benzyl phthalate (BBP), di (2‐ethylhexyl) phthalate (DEHP) and di‐n‐octyl phthalate (DnOP)), were investigated during 2005 and 2006 in the densely populated Seine river estuary. Four compounds, DMP, DEP, DnBP and DEHP were detected at all the stations with DEHP (160–314 ng L^−1^), followed by DEP (71–181 ng L^−1^) and next DnBP (67–319 ng L^−1^), except at la Bouille, where DnBP was the second most important compound. BBP and DnOP concentrations remained low and were not found at all the stations. Considering all six phthalates, Caudebec‐en‐Caux (beginning of the salinity gradient) was the least polluted station (464 ng L^−1^), whereas Honfleur (771 ng L^−1^) and La Bouille (716 ng L^−1^) displayed the highest contamination levels, probably related to important industrial plants. From Caudebec‐en‐Caux to Honfleur (maximum turbidity), variation of DEHP concentration was related to that of suspended matter. In addition, the salinity rise in that area might have facilitated DEHP sorption upon particles. A significant correlation between flow magnitude and DEHP concentration was found (P < 0·01, n = 12), supporting the influence of the hydrological cycle upon contamination. Runoff contribution (56·9 kg d^−1^) to river contamination was confirmed by the annual evolution of phthalate concentrations in the Seine river at Poses. Concentrations of DEHP in the tributaries were in the same range as those of the Seine River (100–350 ng L^−1^), except for two in densely populated and industrialized areas: Robec (800 ng L^−1^) and Cailly (970 ng L^−1^). The treatment plant discharge fluxes were in the same range as those of tributaries (30·4–250 g d^−1^). During high flow periods, the influence of tributaries and of treatment plants seemed to play a minor part in the contamination level of the Seine river estuary. Copyright © 2009 John Wiley & Sons, Ltd.