Temporal changes and factors influencing 137Cs concentration in vegetation colonizing an exposed lake bed over a three-year period

Autor: F.W. Whicker, C.M. Bell, T. Philippi, Thomas G. Hinton
Rok vydání: 1999
Předmět:
Zdroj: Journal of Environmental Radioactivity. 44:1-19
ISSN: 0265-931X
DOI: 10.1016/s0265-931x(98)00074-5
Popis: Activity concentrations of 137Cs in sediments, as well as extractable sediment concentrations of K, Na, Mg, Ca, Mn, Zn and P, pH, percent organic matter and cation exchange capacity, were used as independent variables in an incomplete principal component analysis to identify factors affecting 137Cs activity concentrations in 12 species of native wetland and terrestrial plants invading a recently exposed lake bed. Sediments in the lake had been contaminated 35 years previously from discharges at a nuclear production reactor. 137Cs activity concentrations in plants were positively correlated with sediment concentrations of Na and 137Cs, and inversely correlated to K and pH. Significant decreases in concentrations of sediment constituents (from 3 to 77%), as well as a 42% decline in 137Cs activity concentrations in plants, occurred during the three-year period. Significant differences in 137Cs activity concentrations among plant species, driven by low concentrations in cattails (Typha latifolia), were observed. Terrestrial species had significantly lower activity concentrations of 137Cs than species classified as wetland (arithmetic mean±S.E. of 1069±151 and 2602±394, respectively). Concentration ratios (Bq kg-1 dry plant/Bq kg-1 dry soil) were among the highest reported in the literature (arithmetic mean±S.D.=12.5±28.9; geometric mean=1.6, geometric S.D.=1.4) and were attributed to kaolinitic sediments of pH
Databáze: OpenAIRE
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