M. Wardas et al., VARIABILITY OF HEAVY-METALS CONTENT IN BOTTOM SEDIMENTS OF THE WILGA RIVER, A TRIBUTARY OF THE VISTULA RIVER (KRAKOW AREA, POLAND), Applied geochemistry, 11(1-2), 1996, pp. 197-202
The concentration of heavy metals in the sediments of the Wilga River
has been studied. Comparison of a sample from the city border with tha
t from the river outlet reveals increasing metal concentrations by fac
tors of ca. 27 for Cr, 8 for Cu, 5 for Zn and Ni and 3 for Pb. Since 1
989, for most metals, a decreasing trend in concentrations, at compare
d sampling sites, has been noted. Nevertheless, the amount of heavy me
tals is still rather high and ranges (in mg/kg) as follows: 185-715 Zn
, 38-196 Pb, 27-195 Cu, 3-52 Cr, 3-98 Ni and 1-8 Cd. A strong variabil
ity of metal concentration along the river course has been found. Thei
r elevated concentration results from some sources of pollution situat
ed in the river valley, including: industrial plants, their settling p
onds and busy roads. It is very probable that morphological features o
f the river, like river bends, cause the increase of metal contents. I
t has been found that the amount of heavy metals contributed by grain
fractions <20 mu m is most frequently comparable with or higher than t
he proportions of that fraction in the fine fraction of sediment (< 63
mu m). Copyright (C) 1996 Elsevier Science Ltd