Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

The following studies are available for fenitrothion:

Relevant studies and endpoints

Adsorption/desorption

Relevant study

Endpoints

5.4.1 Key Study, PTRL West Inc, 2002 (HM-0198)Soil Adsorption/Desorption of[14C] Fenitrothion by the Batch EquilibriumMethod (OECD 106).

The Freundlich adsorption coefficients (K values)

Light clay (Kochi): 24

Loam (Hokkaido): 20

Light clay (Wakayama): 30

Sand (Miyazaki): 9

 

Adsorption Koc values

Light clay (Kochi): 1935

Loam (Hokkaido): 816

Light clay (Wakayama): 1659

Sand (Miyazaki): 938

 

Desorption Koc values

Light clay (Kochi): 2177

Loam (Hokkaido): 1061

Light clay (Wakayama): 2074

Sand (Miyazaki): 1042

 

 

5.4.1 Supporting Study, Stauffer Chemical Company/ Western Research Center, 1979

(HW-91-0188),Adsorptionand/DesorptionofSumithioninVarious Soils(Method: according to Federal Register, 40 (123), 26881 (1975))

 

 

The Freundlich adsorption coefficients (Kf values)

(26°C)

Silty Clay loam: 13

Silty clay: 18

Sand: 4.9

Sandy loam: 32

pond: 830

 

Adsorption Koc values (26°C)

Silty Clay loam: 350

Silty clay: 252

Sand: 384

Sandy loam: 1022

pond: 1966

 

Additional information

HM-0198

Results of HPLC analyses of adsorption and desorption solutions in addition to soil samples extracted after completion of the desorption phase, indicated that fenitrothion was partially degraded to 3-methyl-4-nitrophenol (NMC) under the study conditions. The Koc values for desorption were higher than during the adsorption phase, indicating that once adsorbed to the soil fenitrothion is less likely to be removed with water or to leach in these soils (Koc values ranged from 1042 to 2177).

HW-91-0188

On the basis of these findings, fenitrothion is classified as having medium to low mobility according to the McCall classification.  There was no pH dependency on the soil adsorption and desorption for fenitrothion.