Chemical and Microbial Contamination Baseline in t

Authors: Nicolas Lemaire Émilien Pelletier

Publish Date: 2013/05/22

Volume: 65, Issue: 3, Pages: 421-433

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Abstract

Stretching halfway between the Canadian Great Lakes and the Atlantic Ocean the Saguenay–St Lawrence Marine Park is subject to environmental issues being exposed to untreated or uncontrolled point and nonpoint sources of anthropogenic contamination This article provides a first estimation of chemical and microbial contamination entering the marine park from the discharges of local municipal effluents and the inputs of tributaries in the summer period Suspended particulate matter SPM nutrients particulate carbon PC and nitrogen trace metals and fecal coliform bacteria were determined in surface brackish waters at upstream boundaries in freshwater of 11 tributaries and in nine sewage effluents from small communities settled along the marine park Most tributaries have SPM  10 mg L−1 and contributed to a total of ~47 tons day−1 thus representing a small proportion of daily SPM transported by Saguenay River 200 tons day−1 and St Lawrence River 63 × 103 tons day−1 As expected untreated sewage effluents showed high fecal contamination 02–60 × 106 CFU 100 mL−1 high NO x levels 4–33 μmol L−1 and high concentrations of particulate organic carbon 7–62 mg L−1 However all tributaries had low coliforms 230 CFU 100 mL−1 low PC 03–11 mg L−1 and low nutrients NO x   33 μmol L−1 with the exception of the MoulinàBaude River a small tributary 23 × 105 m3 day−1 clearly contaminated by human activities Detailed analysis of 14 metals and metalloids in SPM did not show any clear contamination trend between sewage effluents and tributaries except for GrandesBergeronnes River where most trace metals appeared to be greater than for other rivers Regarding global inputs results showed that despite their relatively high pollutants load inputs from local sewages and small tributaries remained minor contributors compared with upstream inputs ie Saguenay River and St Lawrence River However we illustrate that some local hydrodynamic factors in bays and inlets must be taken into account when evaluating risks associated with sewage dischargesThis study was supported by the Canada Research Chair in Molecular Ecotoxicology and Parks Canada and Parcs Québec comanagement authorities of the SSLMP The authors are grateful to P Poulin S Cloutier and S Pomerleau for the SSLMP team and R SaintLouis P Rioux and D Lavallée for their help during sampling and laboratory work Special thanks to S Sonneville and S StOnge Drouin who modelled the surface currents at ASJ and calculated the estuarine water discharge Thanks are due the Centre d’Expertise Hydrique du Québec and Environment Canada for providing unpublished hydrological and chemical data This article is a contribution to QuebecOcean Network

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