Where has the pollution gone? A survey of organic contaminants in Ho Chi Minh city / Saigon River (Vietnam) bed sediments

Marc Babut (1) , Brice Mourier (2) , Marc Desmet (3) , Caroline Simonnet-Laprade (4) , Pierre Labadie (4) , Hélène Budzinski (4) , Luiz de Alencastro (5) , Tran Anh Tu (6) , Emilie Strady (7, 8) , Nicolas Gratiot (7, 8)

1 RiverLy - Fonctionnement des hydrosystèmes
2 LEHNA - Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés
3 GéHCO EA6293 - GéoHydrosystèmes COntinentaux
4 EPOC - Environnements et Paléoenvironnements OCéaniques
5 EPFL - Ecole Polytechnique Fédérale de Lausanne
6 HCMUS - Ho Chi Minh City University of Science
7 CARE - Centre Asiatique de Recherche sur l'Eau
8 IGE - Institut des Géosciences de l’Environnement

A wide range of persistent organic chemicals, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), some insecticides, as well as polybrominated diphenyl ethers (PBDEs) and some perfluoroalkyl substances (PFASs) were analyzed in 17 bed sediments collected along the Saigon River and at adjacent canal mouths from upstream to downstream in Ho Chi Minh City (Vietnam). Concentrations were rather low for PAHs, as well as for legacy PCBs and dichloro-diphenyl-trichlorethane and metabolites (DDTs), or below detection limits for several PFASs and all PBDEs measured. Several insecticides (chlorpyrifos-ethyl, and the pyrethroids cypermethrin and λ-cyhalothrin) displayed rather high concentrations at a few sites within the city. There was no distinct upstream – downstream trend for PAHs, (DDTs) or PCBs. Although adjacent canal sediments tended to be more contaminated than Saigon River sediments, the differences were not significant. Emissions are almost certainly substantial for PAHs, and probably also for other contaminants such as PBDEs and some PFASs. During the dry season, contaminants are presumably stored in the city, either in canals or on urban surfaces. Heavy rainfall during the monsoon period carries away contaminated particle flows into the canals and then the Saigon River. The strong tidal influence in the river channel hinders the accumulation of contaminated particles. Contaminated deposits should accordingly be investigated further downstream in depositional environments, such as the mangrove.

Mots clés: Saigon River; Sediment; Insecticide; PAH; Perfluoroalkyl substance; Vietnam

Domaines: Biodiversité et Ecologie

Marc Babut, Brice Mourier, Marc Desmet, Caroline Simonnet-Laprade, Pierre Labadie, et al.. Where has the pollution gone? A survey of organic contaminants in Ho Chi Minh city / Saigon River (Vietnam) bed sediments. Chemosphere, 2019, 217, pp.261-269. ⟨10.1016/j.chemosphere.2018.11.008⟩. ⟨hal-02018741⟩