Some Aspects of Sediment Distribution and Macrophyte Cycling of Heavy Metals in a Contaminated Lake

Abstract

Distribution and forms of the metals cadmium (Cd) and zinc (Zn) in sediment and the possible significance of a die‐off of the aquatic macrophyte Potamogeton crispus in Cd cycling in a metal‐contaminated lake were studied. Metal levels in the upper 5 cm of lake sediment ranged from 2.54 ppm Cd and 115 ppm Zn in an uncontaminated area of the lake to 805 ppm Cd and 6,120 ppm Zn near the entrance of a metal‐bearing ditch to the lake. Evidence of metal contamination existed at a depth of 30 cm in sediments in contaminated areas of the system. Dominant forms present in the sediment were the carbonate for Cd and carbonate and organic for Zn. Analysis indicated Cd levels as high as 89.6 ppm in P. crispus in the lake with a maximum burden of 1.5 kg Cd held by the lake's P. crispus population. Release of the total amount could raise water concentrations by a maximum of 1 µg/liter.

Bioaccumulation of Heavy Metals by Aquatic Macrophytes around Wrocław, Poland

“…Investigations concerning their role in the cycling of elements, especially heavy metals, is of particular interest. The uptake of trace metals through the root systems of aquatic plants and subsequent release of metals during decomposition of plant material and transmission of these metals to organisms of higher trophic levels represents a pathway of cycling of trace metals in aquatic ecosystems (McIntosh et al, 1978;Mudroch and Capobianco, 1979). The degree of enrichment depended both on the kind of metal and on the species of plant absorbing the metal.…”

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

“…Furthermore, the ability of rooted macrophytes to accumulate metals from the sediment compartment suggests that aquatic plants can play a role in metal cycling in lakes (Mclntosh et al 1978;Larsen and Schierup 1981) by transferring metals to herbivores, by releasing metals during decomposition Schierup and Larsen 1981), or by secreting metals into the water column (Kraus et al 1986). The cycling will be more effective if metal accumulated in the roots can be transported to the shoots.…”

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

“…However Cowgill (1974) found no interspecific differences in cadmium or copper accumulation between submerged, floating-leaved and emergent plants . Leland and McNurney (1974), Cowgill (1974) andMcIntosh et al (1978) have commented on the great variability of metal concentrations among individuals of the same species ; such variability masks differences and makes seasonal fluctuations hard to detect . Variation may have arisen from differences in ages of individual shoots within the plant stands, or differences in stress levels due to disease, shading, competition or grazing.…”

“…McIntosh et al, 1978) held by the above-ground portions of the macrophytes . At the peak of the standing crop in mid-July, the macrophytes in Indian Bay contained an estimated total of 17 .9 kg cadmium, 14 .7 kg copper and roughly 30 kg of lead (Table 2) .…”

“…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) .…”