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The influence of lipophilicity and formulation on the distribution of pesticides in laboratory‐scale sediment/water systems
Author(s) -
Bromilow Richard H,
Evans Avis A,
Nicholls Peter H
Publication year - 2003
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.540
Subject(s) - pesticide , sorption , lipophilicity , environmental chemistry , sediment , chemistry , lindane , permethrin , partition coefficient , degradation (telecommunications) , water pollution , chromatography , organic chemistry , ecology , adsorption , geology , biology , paleontology , telecommunications , computer science
Pesticide reaching surface waters will be sorbed by sediment. This sorption process and the influence of pesticide formulation have been examined at 10 °C in small‐scale systems having 2‐cm depth of sediment and 8‐cm overlying water stirred gently. Eight pesticides (triasulfuron, isoproturon, chlorotoluron, phenmedipham, difenoconazole, chlorpyrifos, pendimethalin and permethrin), spanning a range of physicochemical properties, were applied individually to the water. Sorption equilibrium was reached at between 15 and 30 days, the proportion of pesticide then in the sediment ranging from 20% for the acidic and therefore polar triasulfuron to 97% for the lipophilic permethrin; this behaviour was not influenced by formulation. Sorption coefficients measured in batch tests over 2 h gave good estimates of the equilibrium distribution. Some degradation was observed for all compounds over 90 days; for some compounds and formulations, enhanced degradation occurred after 20 to 60 days. It is concluded that lipophilicity is the chief determinant of pesticide distribution in sediment/water systems. © 2003 Society of Chemical Industry