Beschreibung:
<jats:p>The work is concerned with the sorption and desorption behaviour of lindane
on four humic acid fractions (HAs) and two humin fractions, sequentially
extracted from Ludas lake sediment. All sorption isotherms, fitted to a
Freundlich model, were nonlinear. The isotherm linearity increased from 0.757
for the first extracted HA to 0.944 for the ninth HA showing a positive
correlation with atomic H/C ratio, while a negative correlation between
sorption coefficient and aliphaticity of the isolated HAs was observed. It
has been shown that the sorption processes may be strongly influenced by the
physical conformation of and accessibility to sediment organic matter (SOM),
as demonstrated by high Koc and low n values of humin samples. Despite
exhibiting the most nonlinear sorption isotherms, humin samples did not show
a pronounced sorption-desorption hysteresis, while the most significant
hysteresis was observed for three HA samples. These results support the
hypothesis that the aromatic domains in SOM influence strongly the sorption
and desorption behaviour of lindane. Our findings may be helpful in
understanding the distribution, transport and fate of lindane in soils and
sediments.</jats:p>