title: Mercury distribution in relation to iron and manganese in the waters of the St. Lawrence river.
abstract: Waters entering the St. Lawrence River from Lake Ontario and from the Ottawa River have been sampled on a quaternary basis between March 1995 and October 1996. Mercury, iron, manganese, organic carbon and other chemical parameters have been determined in the filtered water (< 0.5 micron) and suspended particles (> 0.5 micron). Average total mercury concentrations (+/- standard deviation, number of determinations) in filtered samples were 1.3 +/- 0.9 pM (39) at the mouth of Lake Ontario and 4.0 +/- 2.3 pM (54) at the outlet of the Ottawa River. The respective average concentrations in suspended particles were 1.1 +/- 0.4 (39) and 0.6 +/- 0.2 (55) nmol g-1. Partial correlation analyses reveal that in the fraction < 0.5 micron--which seems to consist of a significant fraction of colloids--mercury was significantly linked to iron, while in the particulate phase, mercury was related to manganese. Mercury was not correlated with organic carbon. A sorption model on iron and manganese hydroxides is proposed to explain these observations.
authors.affiliation: St. Lawrence Centre, Environment Canada, Montréal, Qué, Canada. bernadette.quemerais@ec.gc.ca
authors.forename: B
authors.initials: B
authors.lastname: Quémerais
authors.forename: D
authors.initials: D
authors.lastname: Cossa
authors.forename: B
authors.initials: B
authors.lastname: Rondeau
authors.forename: T T
authors.initials: TT
authors.lastname: Pham
authors.forename: B
authors.initials: B
authors.lastname: Fortin
mesh_terms: D004784:Environmental Monitoring; D005618:Fresh Water / Q000032:analysis*; D007501:Iron / Q000032:analysis*; D008345:Manganese / Q000032:analysis*; D008628:Mercury / Q000032:analysis*; D009864:Ontario; D011792:Quebec
chemical_list: D008345:Manganese; D007501:Iron; D008628:Mercury