Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Summary of degradation

Abiotic Degradation:

The hydrolysis of Flumetsulam as a function of pH was studied (Dawson J, 1995a, according to EEC guidelines, Method C7) and showed that after 120 hours at pH 4, 7, and 9 and 50°C, less than 10% hydrolysis had occurred, demonstrating an equivalent environmental half-life of greater than 1 year at all three pH values. No further testing was necessary, as this investigation indicated that the substance is hydrolytically stable under acidic, neutral, and basic conditions.

Biotic Degradation:

In a Modified Sturm Ready Biodegradability Test (Dawson J, 1995b), the mean cumulative CO2production by mixtures containing Flumetsulam was equivalent to 3% of the TCO2after 29 days. Substances are considered to be readily degradable in this test if CO2production is equal to or greater than 60% of the theoretical value within 10 days of the level first achieving 10%. Flumetsulam is classified as not readily biodegradable.

In an aerobic soil degradation study (Laskowski et al. 1989,according to US EPA 162-1) Flumetsulam degraded to 50% of the amount applied originally within 23 days (sandy loam), 60 days (clay), 93 days (silt loam), and 102 days (loam) at 25°C. Flumetsulam degrades to carbon dioxide and fragments that become incorporated into soil organic matter. During this process no intermediate breakdown products accumulate to significant levels.

Volatilisation

Henry`s Law constant was calculated as 2.64x10-14hPa m3/mole and therefore Flumetsulamcan be considered as not volatile.

Distribution modelling

 

The STP model SimpleTreat, which is incorporated in EUSES 2.1.1 calculates the following STP Distribution:

Fraction of emission directed to air by STP                                      2.53x10-12%              

Fraction of emission directed to water by STP                                  99.7%                       

Fraction of emission directed to sludge by STP                                0.299%                 

Fraction of the emission degraded in STP                                         0%                           

 

Summary of environmental distribution

 

Adsorption/desorption studies (Lehmann et al. 1989 and Goodwin et al. 1989) show that Koc values are in the range of 5 to 74L/kg depending on soil texture, organic carbon content and pH. Flumetsulam can be considered as non volatile and based on the low Koc values to be relatively mobile in the soil. Therefore Flumetsulam is preferentially partitioned to the water phase.

 

Summary and discussion of bioaccumulation

 

Information on bioaccumulation in aquatic species is not required for substances manufactured or imported below quantities of 100 t/y. Therefore nobioaccumulation data are available. However Flumetsulam was determinded to have a log Kow of -1.21 and thesubstance is unlikely to be significantly bioaccumulative (i.e. log Kow <3).

Secondary poisoning

Flumetsulam is concluded to have a low potential for bioaccumulation (log Kow: -1.21). It is therefore highly unlikely food chain effects could occur due to secondary poisoning.