[Effect of sediment characteristics on pesticides sorption and degradation in vulnerable phreatic waters studied in laboratory trials]
1998
Gaus, I. | Casteele, K. vande | Walraevens, K. (Universiteit Gent (Belgium). Lab. voor Toegepaste Geologie en Hydrogeologie)
The contamination of vulnerable phreatic aquifers by pesticides is gaining more attention. Although intense monitoring studies were carried out during the last years, very little is known about the basic processes causing the spread of pesticides in the saturated zone. Here, sorption and decay behaviour of a selection of pesticides with respect to the characteristics of the sediment is studied on laboratory scale. The selection contained basic-neutral (atrazine, simazine) as well as acidic pesticides (MCPA, mecoprop and bentazone). Column experiments carried out to study the sorption behaviour incorporating the kinetic aspects indicate the need for differentiation between reversible and irreversible sorption and the influence of organic matter and clay and silt content on both sorption processes. Decay experiments in thermodynamic equilibrium with the sediment on the other hand proves the high dependency of decay on the presence of (low contents of) organic matter (including microbial activity). The calculated half-life decay times are much longer than those earlier determined in soils indicating a long residence time in the saturated zone and a high contamination potential for some pesticides.
Show more [+] Less [-]AGROVOC Keywords
Bibliographic information
This bibliographic record has been provided by University of Liège