Sorption of carbofuran and diuron pesticides in 43 tropical soils of Sri Lanka.
To better understand the environmental fate of pesticides in Sri Lankan soils, we studied the sorption behavior of two commonly used pesticides (carbofuran and diuron) in 43 surface soils representing a range of soil physicochemical properties from dry and wet zones of Sri Lanka. For carbofuran, the K(d) (L/kg) values varied from 0.11 to 4.1 (mean, 0.83; median, 0.62) and K(oc) ranged from 7.3 to 120.6 (mean, 41.65; median, 36.1), whereas for diuron K(d) values varied from 0.5 to 75 (mean, 9.6; median, 5.15) and K(oc) ranged from 55.3 to 962 (mean, 407; median, 328). A comparison of sorption data on these tropical soils with published studies (mostly European and north American soils) showed that the ranges of sorption coefficients from Sri Lankan soils were within the wide range of K(oc) values reported in the literature. However, these values for both pesticides in soils from dry zones of Sri Lanka were consistently higher (up to two times) than those from the wet zone. The wide range of K(oc) values in Sri Lankan soils may be due to the possible difference in the nature of soil organic carbon, which needs to be further investigated.
Liyanage
Janitha A
JA
CSIRO Land and Water, PMB 2, Glen Osmond, SA 5064, Australia.
Watawala
Ransilu C
RC
Aravinna
A G Piyal
AG
Smith
Lester
L
Kookana
Rai S
RS
D000327:Adsorption; D002235:Carbofuran / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004237:Diuron / Q000737:chemistry*; D006540:Herbicides / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry*; D007700:Kinetics; D012987:Soil / Q000032:analysis*; D013188:Sri Lanka; D014329:Tropical Climate
D006540:Herbicides; D007306:Insecticides; D012987:Soil; D004237:Diuron; D002235:Carbofuran