Évaluation de la biomasse et du contenu en métaux traces des plantes aquatiques submergées du lac Saint-Pierre, fleuve Saint-Laurent.

摘要: Les objectifs du projet etaient premierement d'evaluer la biomasse des plantes aquatiques submergees lac Saint-pierre au maximum de saisonnier meme qu'en periode senescence, pour, dans un deuxieme temps, en estimer le contenu metaux traces. L'echantillonnage s'est deroule aout et octobre 1990. En utilisant les images multispectrales d'un capteur aeroporte MEIS-II, etalonnees avec donnees terrain, Lavoie al. (1991) ont estime macrophytes submerges Saint-Pierre juillet A partir valeurs carreaux 4 km X concentration contaminants a 17 stations lac, technique krigeage permis d'estimer 36 kg Cd, 98 Cr, 557 Cu, 314 Ni, 69 Pb 2,580 Zn quantites retenues parties vertes submergees. Pour instant donne, retrouvees superieures celles dissoutes colonne d'eau pour Zn, mais nettement inferieures sediments mobiles. Pendant estivale, compartiment "macrophyte" retiendrait <1% Ni Cu dissous l'eau qui passe pendant l'ete, 2,2% 2,5% Cd 4,1% Pb. La perte observee mois d'octobre derive debris suggerent que associes aux sortent fin l'ete. Saint-Pierre, particulierement vallisnerie americaine, montrent leur utilite tant bio-indicateurs traces, refletant contamination milieu partie biodisponible potentiellement transmissible chaine alimentaire. The objectives of this project were to evaluate the biomass Lake st-pierre submerged aquatic plants, both at peak seasonal and during senescence period, estimate total content trace metals contained in above-ground portion vegetation. The plants was determined 27-40 August October 1990; multispectral remote sensing data (MEIS-II) used extrapolate from these point estimates (gjm2) entire lake area (Lavoie al., 1991). Samples plant community (dominated by Vallisneria americana Potamogeton sp.) also collected for metal analysis (Cd,Cr,cu,Fe,Mn,Ni,Pb,Zn). By combining two bases (biomass; concentrations), using appropriate geostatistical techniques (kridging), we have estimated storage plants: Zn. At any given time peak, quantities stored higher than those dissolved water column, but much lower present mobile sediments. Mass balance calculations summer months (120 d) indicate that compartment would retain entering lakei calculated retentions are slightly (2,2%), (2,5%) (4,1%). loss downstream drifting material noted suggest associated with parts vegetation not recycled within lake, exported end summer. Submerged st-Pierre, particularly (wild celery), show potential as bioindicators metals, reflecting spatial variations environmental contamination; macrophyte potentially transferable through food chain organisms.