5.1 Summary of residue data
The following assessment is based on MRL review of the active substance thifensulfuron methyl (EFSA Journal 2012;10(8):2863), and study evaluation document: 20171184 Harmony SAVA res V01, Ctgb, 2017.
5.1.1 Metabolism in plants
The metabolism of thifensulfuron-methyl was investigated in field grown wheat following foliar spray application of radiolabelled active substance at the application rate of 74-80 g as/ha at the 5 leaves stage. The elimination of thifensulfuron-methyl was rapid (approximately 2 days). Total residues in mature forage and straw were in the range of 0.45-0.80 mg/kg for the radiolabelled test material. No significant residues (<0.01 mg/kg) of the parent compound or its metabolites in mature wheat grain were detected two months after treatment. An additional metabolism study on soya bean was reported by the RMS during the Member State consultation. No significant residues (≤ 0.01 mg/kg) of the parent compound or its metabolites in soybean seed or pods were detected at harvest (100 days after treatment). Therefore the residue definition for risk assessment and enforcement was
thifensulfuron-methyl. This residue definition is limited to the evaluated foliar use on cereals and pulses & oilseeds.
The requested use of thifululfuron-methyl as a foliar application on soya beans is covered by the metabolism data available.
5.1.2 Metabolism in livestock
In the peer review the metabolism of thifensulfuron-methyl was investigated in lactating goats. The study demonstrated that the major metabolic pathway involved cleavage of the carboxyl ester linkage, resulting in the formation of thifensulfuron acid. Oxidative O-demethylation occurred to a limited extent. The major residue in milk, muscle and tissues was thifensulfuron-methyl. The general metabolic pathways in rodents and ruminants were found to be comparable; the findings in
ruminants can therefore be extrapolated to pigs.
5.1.3 Residue definition (plant and animal)
The residue definition for both plants and animals for enforcement and risk assessment is the parent thifensulfuron-methyl.
5.1.4 Stability of residues
Thifensulfuron-methyl is proven to be stable for at least42 months and 24 months at -20 °C in dry commodities (wheat grain and corn respectively). In high oil commodities (cotton seed)
thifensulfuron-methyl is proven to be stable for a period of 14 months at -20 °C. The available storage stability data covers the intended use of soybean and the storage stability time in the supervised residue trials.
5.1.5 Supervised residue trials
Soybean (cGAP-NL: field broadcast spray, 1x7.5 kg as/ha, BBCH 10-16 after emergence, PHI=n.a.) In the existing authorisation use on maize and fodder grass is authorised. The requested use on soybean does not fall within the existing risk envelope. Therefore the applicant provided two studies with thifensulfuron-methyl on soybean. Four trials performed in Austria according to the proposed cGAP are previously evaluated during the Article 12 MRL review (EFSA Journal 2012;10(8):2863). The residues in soya bean are all below the LOQ of 0.01 mg/kg.
A new study investigating the residues after application of thifensulfuron-methyl in four NEU trails on soybean are evaluated by Ctgb within this application (20171186 SAVA Harmony). The trails were considered acceptable and all residues in mature soybean seed were below the LOQ of 0.01 mg/kg.
All residues of thifensulfuron-methyl in mature soybean seeds are below the LOQ of 0.01 mg/kg. The current EU-MRL in soybean is 0.01* mg/kg and an exceedance of the current MRL is therefore not expected when the product is applied according to the requested GAP.
Table R1: Selected residue levels from trials with thifensulfuron-methyl
Crop Residue levels (mg/kg) STMR
(mg/kg)
HR (mg/kg)
soybean 8x<0.01 mg/kg 0.01 0.01
5.1.6 Residues in succeeding crops
The metabolism of thifensulfuron-methyl in rotational crops peas, beetroot, sunflower and wheat has been evaluated in the Draft Assessment Report prepared by France in 1996. Field studies on residues in succeeding crops are not required as thifensulfuron-methyl dissipates rapidly in soil without exposing crops to significant soil residual concentrations. Based on the rapid degradation of thifensulfuron-methyl in soil and the findings of the above metabolism studies, detectable residues are not expected in rotational crops.
5.1.7 Residues from livestock feeding studies
Thifensulfuron-methyl is authorised for use on several crops that might be fed to livestock, including soya beans. The median and maximum dietary burdens were calculated in the Article 12 MRL review using the agreed European methodology, including soybean . The calculated dietary burdens for all livestock groups, except poultry, were found to exceed the trigger value of 0.1 mg/kg DM.
According to the above mentioned metabolism study, it is concluded that, after exposure to the maximum dietary burden (about 25 times lower than the dose level of the metabolism studies), residue levels in ruminants and swine commodities are expected to remain below the default MRL of 0.01 mg/kg as defined by Regulation (EC) No 396/2005. Hence, no livestock feeding study is needed.
5.1.8 Processing factors
As quantifiable residues of thifensulfuron-methyl are not expected in the treated crops, there is no need to investigate the effect of industrial or household processing. In addition, the chronic exposure does not exceed 10 % of the ADI.
5.1.9 Calculation of the ADI and the ARfD
The Acceptable Daily Intake (ADI) of thifensulfuron-methyl is 0.01 mg/kg bw per day based on the 2 year rat toxicity study, with an uncertainty factor (UF) of 100.
During the renewal of thifensulfuron-methyl an ARfD was set at 2 mg/kg bw. Previously no ARfD was set.
5.2 Maximum Residue Levels
EU-MRLs are present in Regulation (EU) No 617/2014.
5.3 Consumer risk assessment
Risk assessment for chronic exposure through diet
A calculation of the Theoretical Maximum Daily Intake (TMDI) was carried out using EFSA PRIMo rev.
2.0, containing all available Member State diets, during most recent Review of the existing MRLs for thifensulfuron-methyl (EFSA Journal 2012;10(8):2863).
The maximum TMDI is 3.8% of the ADI for Dutch children, with the highest contributor milk and milk products. The TMDI is 1.1% of the ADI for the Dutch general population.
Risk assessment for acute exposure through diet
With such a high ARfD and residue levels in soybean seeds below 0.01 mg/kg, an acute risk to the consumer is not expected.
Conclusion
Based on the assessment for residues, no risk for the consumer due to the exposure to thifensulfuron-methyl is currently expected. The current EU-MRL in soybean is 0.01* mg/kg,
therefore, based on the available data and supervised residue trials provided by the applicant within this application, MRL exceedance is not expected. The requested use on soybean can be authorized within this application.