Behavior of anionic and nonionic surfactants and their persistent metabolites in the Venice lagoon, Italy

The occurrence and behavior of the aromatic surfactants linear alkylbenzene sulphonates (LAS) and nonylphenol polyethoxylates (NPE) as well as their b iotransformation products in the central lagoon of Venice, Italy, were inve stigated by monitoring deep- and shallow-water lagoon stations, two riverin e sites, and one sea station. Additional samplings were conducted at the th ree inlets connecting the lagoon with the open sea under both ebb and low-t ide conditions, and a radiometrically dated sediment core spanning the last century was examined. The spatial distributions of LAS, NPE, and their car boxylic metabolites sulphophenyl carboxylates and nonylphenol carboxylates, respectively, appeared to be rather homogeneous over the entire central la goon. Remarkable seasonal differences were found, however, primarily becaus e of the increased biodegradation at temperatures greater than 20 degrees C . The estimated primary and ultimate biodegradations of LAS in the lagoon w aters were approximately 90 and 72%, respectively. Analysis of the dated se diment core showed similar annual fluxes of both LAS and NPE (48 ng/cm(2) y ear), which were between previously reported values of polychlorinated biph enyls (4.7 ng/cm(2) year) and polycyclic aromatic hydrocarbons (167 ng/cm(2 ) year).