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Atrazine and metribuzin sorption in soils of the argentinean humid pampas
Author(s) -
Daniel Peter E.,
Bedmar Francisco,
Costa José L.,
Aparicio Virginia C.
Publication year - 2002
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620211207
Subject(s) - metribuzin , atrazine , sorption , soil water , chemistry , environmental chemistry , total organic carbon , cation exchange capacity , silt , leaching (pedology) , organic matter , partition coefficient , freundlich equation , soil science , adsorption , agronomy , pesticide , environmental science , chromatography , geology , organic chemistry , weed control , paleontology , biology
Laboratory studies were conducted to determine the influence of surface and subsurface properties of three representative soils of the humid pampas of Argentina on atrazine and metribuzin sorption. Atrazine and metribuzin sorption isotherms were constructed for each soil at four depths. Sorption affinity of herbicides was approximated by the Freundlich constant ( K f ), distribution coefficient ( K d ), and the normalized K d based on organic carbon content ( K oc ). Multiple regression of the sorption constants against selected soil properties indicated that organic carbon content (OC) and silt were related positively and negatively, respectively, to atrazine K f coefficient ( r 2 = 0.93), while K d coefficient of atrazine was related positively to organic carbon content and negatively to both silt and cation exchange capacity (CEC) ( r 2 = 0.96). For metribuzin, only organic matter content was related positively to K f coefficient ( r 2 = 0.51). Lower K f values for atrazine were obtained for all soils with increasing depth, indicating lesser sorption at greater depths. Metribuzin sorption was quite similar across all depths. Sorption constant K f of atrazine ranged from 2.06 to 7.82, while metribuzin K f values ranged from 1.8 to 3.52 and were lower than atrazine for all soils and depths, indicating a greater leaching potential across the soil profile.