Trace metals in submerged plants of the St. Lawrence River

Abstract

ST-CYR, L., and CAMPBELL, P.G.C. 1994. Trace metals in submerged plants of the St. Lawrence River. Can. J. Bot. 72: 429-439. Vallisneria arnericana Michx. (wild celery), a submerged plant ubiquitous in the fluvial lakes St. Louis and St. Pierre of the St.Lawrence River, Quebec, shows potential as a bioindicator species for trace metals in its environment. The Cd, Cr, Cu, Ni, Pb, and Zn concentrations in V. arnericana leaves reflect spatial variations in environmental contamination and represent bioavailable trace metals potentially transferable through the food chain to higher orgaeisms. With the exception of Pb, V. arnericana concentrates trace metals to higher levels in its aboveground tissues than does Potarnogeton richardsonii (A. Bennett) Rydb., another abundant species in the studied lakes, although the two species show the same trend to higher trace metal concentrations at the more contaminated stations. Vallisneria arnericana from Lake St. Pierre shows higher concentrations for all trace metals studied than does the same species from Lake St. Louis (mean concentrations in pg/g dry wt. for Lake St. Pierre versus Lake St. Louis: Cd, 1.62 vs. 0.89; Cr, 3.9 vs. 2.5; Cu, 20.0 vs. 16.5; Ni, 13.1 vs. 5.6; Pb, 3.3 vs. 2.0; Zn, 130 vs. 91). Mean concentrations of Cd, Cr, Ni, and Zn exceed median values of these concentrations for aquatic plants from contaminated sites, as reported in the literature. Key words: Vallisneria arnericana, Potarnogeton richardsonii, bioindicator, trace metals, St. Lawrence River. ST-CYR, L., et CAMPBELL, P.G.C. 1994. Trace metals in submerged plants of the St. Lawrence River. Can. J. Bot. 72 : 429-439. La vallisnCrie amtricaine (Vallisneria urnericann Michx.), une plante submergke omniprksente dans les lacs fluviaux St-Louis et St-Pierre du fleuve St-Laurent, QuCbec, montre un potentiel intiressant en tant qu'espkce bioindicatrice des mCtaux traces dans son environnement. Les concentrations en Cd, Cr, Cu, Ni, Pb et Zn des feuilles reflktent la contamination du milieu et repkentent la partie biodisponible des metaux potentiellement transmissible dans la chaine alimentaire. A I'exception du plomb, la vallisnCrie concentre davantage les mCtaux traces dans ses tissus que le potamot de Richardson (Potarnogeron richardsonii (A. Bennett) Rydb.), autre espkce assez rCpandue dans les lacs CtudiCs, bien que les deux espkces montrent la m&me tendance d'avoir des concentrations plus ClevCes en mCtaux traces aux m&mes stations les plus contaminkes. La vallisnCrie du lac St-Pierre a des concentrations supirieures pour tous les mttaux traces CtudiCs B celle provenant du lac St-Louis (concentrations moyennes, en pg/g poids sec, respectivement, pour les lacs St-Pierre et St-Louis : Cd, 1,62 vs. 0,89; Cr, 3,9 vs. 2,s; Cu, 20 vs. 16,5; Ni, 13,l vs. 5,6; Pb, 3,3 vs. 2,O; Zn, 130 vs. 91). Les concentrations moyennes en Cd, Cr, Ni et Zn sont supCrieures B ce qui est rapport6 dans la IittCrature pour des plantes aquatiques provenant de plans d'eau contaminks. Mots ~1 . 4~ : Vallisneria americana, Potarnogeton...

Seasonal variation of metal accumulation and translocation in yellow pond-lily (Nuphar lutea)

“…St-Cyr and Campbell (1994) found out that the metal concentrations in the above-ground parts of submerged plants tend to vary throughout the growing season which 184 Seasonal variation of metal accumulation and translocation in yellow pond-lily (Nuphar lutea) supports our findings. Ray and White (1979) revealed that generally metal concentrations of Equisetum arvense were higher in July, when plants were growing, than in September.…”

Temporal and spatial distribution and production of dissolved gaseous mercury in the Bay St. François wetland, in the St. Lawrence River, Quebec, Canada

“…Second, submerged macrophytes would be able to adsorb and/or absorb Hg(II) and consequently could limit Hg availability for photoreduction. It has been shown that, in contrast to floating plants, submerged species tend to act as accumulators rather than sources of trace metals, including Hg (St-Cyr and Campbell, 1994;ThompsonRoberts et al, 1999). Third, macrophytes could absorb newly produced Hg(0).…”

Metal accumulation in American wild celery (Vallisneria americana Michx.) in the St. Lawrence River: effects of water depth and exposure to current

“…), including some below-ground tissues of the last one. However, the comparison was nevertheless deemed valid, since between-species comparisons carried out in the St. Lawrence River (St-Cyr and Campbell 1994;Hudon and Lalonde 1998) showed that V. americana concentrates metals more efficiently than do other species of SAV. In addition, below-ground tissues represent a negligible fraction of total Myriophyllum sp.…”

“…Monitoring programs should control for plant species (Ray and White 1976;Mudroch and Capobianco 1979;Sprenger and McIntosh 1989;St-Cyr and Campbell 1994), time of collection (Dykyjová 1973;Gommes and Muntau 1981), and anatomic structure and plant tissue (Miller et al 1983). Metal concentrations in SAV can also vary with biological factors such as seasonal metabolism and growth (Mudroch and Capobianco 1979).…”

“…Regardless of the differences in water quality and metal concentrations, V. americana is the dominant submerged macrophyte species in both rivers, where it is found over a broad range of water depth, light intensity, current speed, and sediment type (St-Cyr and Campbell 1994;Hudon 1997) (Table 1). Since this species produces new above-and below-ground tissues every year from small overwintering structures, it is well suited to monitoring yearly variations in metal concentrations.…”