Uptake of Heavy Metals from Contaminated Soils by Salt-Marsh Plants

摘要

In 1984 a greenhouse experiment was carried out with Spartina alterniflora, Aster tripolium and Puccinellia maritima. Uptake of heavy metals from contaminated soils dredged from the Western Scheldt estuary was measured in these plants. After the first harvest, the underground parts of the plants were left untouched to allow regrowth for an additional 90 days period. After this period the buckets were again harvested and the shoots analyzed. During both the growth and regrowth phases, the plants were kept in buckets with different water and salinity regimes: inundated versus drained, high salinity versus low salinity. Regrowth was very bad for Aster tripolium and for Puccinellia maritima at high salt conditions. Therefore only the results of P. maritima growth at low salt conditions and S. alterniflora wre statistically analyzed. Out of 42 comparisons between the first and the second harvest, with respect to Cd, Pb, Fe, Mn, Cu, Zn, and As levels, 25 gave statistically significant differences. Levels of CD, Mn and Cu of the regrowth shoots of the second harvest were higher in general than of the first harvest. In contrast, levels of Fe generally were lower. Comparisons of Pb, Zn and As levels gave variable results.