Uptake of Cadmium and Lead by a Rooted Aquatic Macrophyte (Elodea Canadensis)

Abstract

The role of roots in the uptake of nonessential trace metals by aquatic macrophytes was investigated Elodea canadensis. Plants were grown in 2 lakes in which metal concentrations in the water differed. Specimens in each lake were anchored in either control sediment or in sediment contaminated with Cd and Pb. Plants grown in the same water but in sediment from different sources had significantly different concentrations of the 2 metals. Elodea samples rooted in sediments from the same source but grown in water with different levels of metals also accumulated significantly different amounts of Cd and Pb. Thus the importance of both sediment and the surrounding water as sources of metals for aquatic plants was demonstrated. Samples grown in water and sediment containing low levels of metals had minimal concentrations of 0.32 mg/g Cd and 5.2 mg/g Pb, while plants grown in metal—contaminated water and sediment accumulated up to 32.33 mg Cd/g and 160.9 mg Pb/g.

Mercury uptake from contaminated water and sediment by the rooted and submerged aquatic macrophyte Eriocaulon septangulare

“…Evidence for such acropetal transport of metals varies with the metal and plant species studied. For instance, Welsh and Denny (1979) reported acropetal translocation of Cu, but not Pb, in two species of Potamogeton, although earlier studies (Welsh and Denny 1976;Mayes et al 1977) provided evidence of acropetal translocation of Pb in submerged aquatic plants. In the study by Mayes et al (1977), the authors considered that movement of Pb from contaminated sediment to the foliage of Elodea canadensis probably occurred through the water.…”

“…For instance, Welsh and Denny (1979) reported acropetal translocation of Cu, but not Pb, in two species of Potamogeton, although earlier studies (Welsh and Denny 1976;Mayes et al 1977) provided evidence of acropetal translocation of Pb in submerged aquatic plants. In the study by Mayes et al (1977), the authors considered that movement of Pb from contaminated sediment to the foliage of Elodea canadensis probably occurred through the water. Similarly, field observations of correlations between shoot and sediment Pb concentrations (Welsh and Denny 1976) probably reflected releases of Pb from the sediment affected by the turbulence and/or reduced redox potentials, and their subsequent uptake by the shoots (Welsh and Denny 1979).…”

“…The relative importance of these two routes for nutrient or for metal uptake, respectively, is not clear, although it is accepted that both pathways may operate in the same plant (Denny 1980). The route of metal uptake depends upon a number of factors including plant species, type of metal and its chemical form, and relative metal concentrations in the root and shoot environments (Mayes et al 1977;Denny 1980;Welsh and Denny 1980;Campbell et al 1985Campbell et al , 1988.…”

Metal contamination in sediments and biota of the Bay of Quinte, Lake Ontario, Canada

“…It was hypothesized that trace element levels in sediments and plants would be higher in sites at Belleville, close to potential contaminant sources, than in Hay Bay which was thought to be relatively isolated. Aquatic macrophytes are capable of bioaccumulating a number of trace elements (Mayers et al, 1977;Agami & Waisel, 1986) and therefore serve as potential biomonitors. Hydrophytes in the Moira River valley north of the Bay of Quinte have been found to contain high levels of As, Co, Cu, and Ni (Mudroch & Capobianco, 1979).…”

Cadmium, copper and lead in aquatic macrophytes in Shoal Lake (Manitoba-Ontario)

“…Of particular interest is the role of macrophytes in the cycling of metals within aquatic ecosystems (McIntosh, 1975) . Not only do aquatic macrophytes take up metals from the sediments and water, and subsequently release these elements on aging and decomposition (Mayes et al, 1977 ;McIntosh et al, 1978), they also serve as food for higher trophic levels which can obtain a significant proportion of their body burdens of metal from this source (e .g . Newman & McIntosh, 1983) .…”