Colloque

Natural and Pollutant Hydrocarbons in St. Lawrence Sediments

R.M. Lambert

J.N. Searing

Membre a labase

R.M. Lambert

Résumé du colloque

Hydrocarbons were measured in sediments from seven box cores. Sampling stations ranged over the St. Lawrence Estuary and Gulf (5 to 34 per mile square), to 550m water depth and included (1) a shallow, urbanized basin, (2) a fjord, (3) an estuarine upwelling zone, and (4) the open basin in the Gulf. Concentrations of n-alkanes declined exponentially with distance from the St. Lawrence River. A series of branched alkanes (C20 and C25) showed different spatial distribution, reflecting their possible origins. Individual regions could be distinguished on the basis of their hydrocarbon pattern using principal component analysis. Sediment samples were also collected with depth in each core, including the top few millimeters of unconsolidated surface flocculent material. These samples had a greater proportion of compounds produced in situ and were compared with the hydrocarbons in phytoplankton and zooplankton collected in the Lower Estuary and those found in aliquots of the same plankton degraded in the laboratory.