Scientific Committee on Plants
Outcome of discussions
regarding the evaluation of Flurtamone in the context of
Council Directive 91/414/EEC concerning the placing of
plant protection products on the market (opinion adopted by
the Committee on 26 January 2001)
OPINION OF THE SCIENTIFIC COMMITTEE ON
PLANTS ON THE EVALUATION OF FLURTAMONE IN THE CONTEXT OF
COUNCIL DIRECTIVE 91/414/EEC CONCERNING THE PLACING OF
PLANT PROTECTION PRODUCTS ON THE MARKET
(Opinion adopted by the Committee on 26
2. TERMS OF REFERENCE
Following the opinion adopted by the
Scientific Committee on Plants in 1998
, the notifier has submitted new data to
the Commission services.
The Scientific Committee on Plants (SCP)
is now requested to respond to the following questions in
the context of the Commission's work on the implementation
of Council Directive 91/414/EEC concerning the placing of
plant protection products on the market.
1. "Do the soil metabolites of
flurtamone, particularly 3-trifluoromethylbenzoic acid
(TFMBA), represent a risk for contamination of
2. "In the light of the new information
submitted by the notifier, can the Committee confirm that
Trifluoroacetic acid (TFAA) does not represent an
unacceptable risk to groundwater?"
Flurtamone is a new active substance in
the context of Directive 91/414/EEC
. In 1998, the Committee was consulted
by the European Commission on the inclusion of flurtamone
in Annex I to Directive 91/414/EEC. The opinion of the
Committee was adopted on 18 December 1998. In its
conclusions the SCP highlighted certain unresolved issues
for the metabolites TFMBA and TFAA.
With respect to TFMBA, the SCP
recommended the inclusion of soils with pH values between 7
and 8 in the sorption studies with this metabolite. The
notifier (Rhône-Poulenc, now Aventis CropScience) agreed to
perform these studies. The results have now been submitted
to the Committee.
As regards the metabolite TFAA, in the
1998 opinion, the Committee concluded that the data made
available did not enable to assess the risk of
contamination of ground water by the said metabolite. The
notifier has now submitted new data on the aquatic
ecotoxicity of TFAA and a health risk assessment for this
4.1 Question 1:
"Do the soil metabolites of flurtamone, particularly
3-trifluoromethylbenzoic acid (TFMBA), represent a risk
for contamination of groundwater?"
Opinion of the Committee:
The Committee concludes that concentrations of TFMBA
leaching to groundwater are expected to be below 0.1
g/l for soils with pH values that are not
greater than 5. For most soils with pH values greater than 5,
concentrations will remain below 0.1
g/l. However, in a small percentage of
cases/situations, concentrations exceeding 0.1
g/l may occur. The Committee concludes
that use scenarios exist for flurtamone which pose no
unacceptable risk to groundwater with respect to leaching of
the metabolite TFMBA.
Technical background on which the opinion is
Laboratory studies on the soil
metabolism of flurtamone show that about 40% CO
2 and about 30% soil-bound residues are formed.
In these studies two soil metabolites have been identified:
3-trifluoromethylbenzoic acid (TFMBA) and trifluoroacetic
acid (TFAA). Both laboratory studies and field studies have
shown that flurtamone can be transformed into TFMBA at
levels above 10% of the applied amount in soils. In
metabolism studies with flurtamone in three soils TFMBA
reached maximum levels of 8.3 and 10.8% of the
radioactivity dose in two soils whereas it was not detected
in the third soil. In field studies TFMBA reached a maximum
level of 11% of the dose. In its opinion of 1998, the
Committee estimated the half-life of TFMBA at approximately
50 days for a sandy loam soil at 22 °C. At that time no
sorption data were available for TFMBA. The Committee
recommended to include soils with pH values between 7 and 8
in the sorption studies with TFMBA that the notifier had
already agreed to perform. Since the 1998 opinion, the
following new experimental information on behaviour of
TFMBA was provided by the notifier:
1. The pK
A (dissociation constant) of the COOH-group in
the TFMBA molecule is 4.2.
2. Adsorption of TFMBA was studied in
four soils and the transformation rate was studied in three
soils. The results are described in the following
(0.01 M CaCl
Given the pK
A of 4.2, the adsorption of TFMBA is expected to
vary strongly with pH in the range from pH 4 until about 6.
Therefore the adsorption studies with the clay loam and
loam soils give realistic worst-case K
OC values (15 and 16 l/kg).
The notifier provided additionally
simulations for TFMBA leaching using the model PELMO 3.00 and
using a soil and weather scenario as used in German pesticide
registration. Using the worst-case K
OC and half-life combination from the above table
(15 l/kg and 16 days), concentrations of TFMBA were
calculated to be lower than 0.001
g/l. The Committee checked this by
estimating TFMBA leaching with the PESTLA 1.1 model and the
Dutch standard scenario (based on model output published in
J. Environ. Qual. 20: 425-435). TFMBA was treated as if it
was a parent compound. The Dutch standard scenario is based
on a dose of 1 kg/ha. The assessment was based on a TFMBA
application of 24 g/ha in spring assuming a linear
relationship between dose and leaching (a conservative
approach). An estimated groundwater concentration of
g/l was found which is also far below the
limit value of 0.1
Accordingly the results of the new
laboratory studies on adsorption and transformation rate in
soil indicate that leaching to groundwater would always
remain below 0.1
g/l. However, using one of the soil
metabolism studies (soil with pH=6.4) from the monograph, the
Committee estimated the half-life of TFMBA of about 50 days
oC (corresponding with a half-life of 43 days at
oC). Such a half-life would probably result in
estimated groundwater concentrations of TFMBA exceeding
g/l. A previously reported lysimeter study
(soil with pH=6) resulted in an average concentration over a
three year period of TFMBA of 0.09
g/l after application in two successive
years implying that annual average concentrations of TFMBA
g/l were measured.
With respect to the metabolite
trifluoroacetic acid (TFAA) no new experimental information
with respect to fate in soil was provided.
4.2 Question 2
"In the light of the new information submitted by the
notifier, can the Committee confirm that trifluoroacetic
acid (TFAA) does not represent an unacceptable risk to
Opinion of the Committee:
Based on the new data supplied, the Committee supports
the assessment of the RMS that the observed leaching of
TFAA does not represent an unacceptable risk to aquatic
organisms via groundwater. This is due to the lack of
effect on primary productivity in mesocosms, the evidence
of very low toxicity on algae,
Daphnia, fish and terrestrial plants, and the
difference between concentrations in the leachate and
lowest observed toxicity. The toxicological information
made available to the Committee is insufficient for a
full assessment of TFAA.
Scientific background on which the opinion is
Originally, the SCP had given the
following opinion (excerpt of SCP/FLURT/004-Final, Opinion
expressed by the SCP on 18 December 1998):
In a duplicate lysimeter study the soil metabolite
trifluoroacetic acid (TFAA) was shown to leach at average
concentrations over a three-year period of 1.4 and
g/l and accordingly represents a risk for
contamination of groundwater. On the basis of aquatic
toxicity data it was stated (1) that "TFAA is of low concern
for the risk of aquatic organisms". However, these data were
not included in the documentation submitted to the Committee.
Furthermore, reference was made to data (1) on TFAA
phytotoxicity and human toxicology that was also not
submitted to the Committee. Therefore the Committee is unable
to assess whether TFAA represents an unacceptable risk for
contamination of groundwater
Subsequently, additional information was
submitted to the SCP in September 1999 (SCP/FLURT/006 -
011), which was evaluated by the RMS in an addendum to the
monograph of February 2000 (SCP/FLURT/013). The Committee,
in order to be able to finalise the assessment, then
requested the full report of a specific study (Bott &
Standley; ref. 14-15) which was submitted in August
The available data on aquatic toxicity of
TFAA show rather low toxicity on a wide range of algal
species. The NOEC
values are above 100 mg/l, with one
Scenedesmus capricornutum) at 0.12 mg/l. On
terrestrial crop and weed plants, there was no phytotoxicity
at rates up to 250 g/ha. Undiluted lysimeter leachates showed
For fish and
Daphnia, toxicity of TFAA was very low (LC/EC
> 1200 mg/l).
Because of the occurrence of TFAA in the
atmosphere as a metabolite of industrial chemicals
(substances replacing ozone-depleting chlorofluorocarbons), a
stream mesocosm study had been conducted (Bott & Stanley,
1995) to assess the effect of TFAA on biological processes in
small streams. Following 5 months of exposure to 31-32
g/l TFAA in the streams, samples of the
microbial community were measured for activity. Primary
productivity (measured as chlorophyll a) was unaffected by
concentrations of up to 200 mg/l TFAA. However, the excretion
of photosynthetate (measured as dissolved organic
14C, thus reflecting the net balance of the
microbial community of producers and consumers) by the
microbial community differed significantly in one part of the
study. The mechanism of this effect could not be entirely
clarified but indications exist that the bacterial part of
the community adapted to TFAA during the 5 months of
preceding exposure to 31-32
g/l, and was now more efficiently
metabolising TFAA as compared to unacclimatised
Macro-invertebrates were sampled twice
(April and July) during the stream mesocosm studies.
However, the exact method of sampling was not described,
and there are unexplained inconsistencies (i.e., Coleoptera
and Ephemeroptera being counted at one sampling date but
merely recorded for presence at the other sampling date).
Hence, the following results have to be qualified as
Amphipods, oligochaetes and
Ephemeroptera larvae were most abundant. Numbers of sampled
animals or their recorded presence showed the variability
typical for such studies, with no obvious effect of
In summary, the database for TFAA is
rather extensive in comparison to that for other metabolites.
While stream mesocosm data suggest that continuous exposure
(> 5 months) to TFAA at levels of 31-32
g/l may cause adaptation in the physiology
of stream bacterial communities, the Committee observed that
this change should not be seen as a negative effect in this
case, biological degradability being desired for substances
introduced into the environment. Therefore, the Committee
supports the assessment of the RMS that the observed leaching
of TFAA does not represent an unacceptable risk to aquatic
organisms via groundwater because of:
the lack of effect on primary
productivity in those mesocosms,
the evidence of very low toxicity on
Daphnia, fish and terrestrial plants, and
the difference between concentrations
in the leachate and lowest observed toxicity.
A few mammalian toxicology data on TFAA
were made available to the Committee. TFAA seems to be of
moderate acute toxicity (oral rat LD
200-400 mg/kg body weight) and is irritant
to the skin. It induces peroxisome proliferation in rats
repeatedly treated with very high doses (150-400 mg/kg body
weight per day) and inhibits pyruvate kinase activity. Two
bacterial mutagenicity studies gave negative results.
Reproduction, developmental and long-term toxicity and
carcinogenicity studies are missing. Summaries of inhalation
and oral long-term/carcinogenicity studies with
1,1,1,2-tetrafluoroethane, which are partly metabolised to
TFAA, were made available by the Notifier. However, the
toxicological information made available to the Committee is
insufficient for a full assessment of TFAA.
1. Opinion of the Scientific Committee
on Plants regarding the inclusion of flurtamone in Annex I
to Directive 91/414/EEC concerning the placing of plant
protection products on the market adopted on 18 December
2. Boesten JJTI & van der Linden AMA
(1991) Modeling the influence of sorption and
transformation on pesticide leaching and persistence. J.
Environ. Qual. 20: 425-435.
6. DOCUMENTATION MADE AVAILABLE TO THE COMMITTEE
1. Monograph prepared in the context of
the inclusion of flurtamone in Annex I to Council Directive
91/414/EEC. Ministère de l'Agriculture, de la Pêche et de
l'Alimentation, Direction générale de l'alimentation,
France - March 1997.
2. Flurtamone: computer simulation of
the potential for mobility of the metabolites TFMBA and
TFAA in soil using the PELMO 3.00 model. G Reinken (1999).
RPA Study 17862. Rhône-Poulenc Agriculture Limited, Ongar,
14C]-3-Trifluoromethylbenzoic acid rate of
degradation in three soils. CM Burr (1999). RPA Study
15616. Rhône-Poulenc Agriculture Limited, Ongar, UK.
adsorption/desorption to and from four soils. MB Simmonds
& CM Burr (1999). RPA Study 15618. Rhône-Poulenc
Agriculture Limited, Ongar, UK.
5 Flurtamone: further assessment on the
section fate and behaviour, submitted by France July, 9
1999. (Doc. SCP/FLURT/006).
6 Flurtamone: supplemental dossier # 3
for the evaluation of the active substance flurtamone
according to Council Directive 91/414/EEC, P.E.Th. van der
Kouwe, Rhône-Poulenc, July, 1 1999. (Doc.
7 Flurtamone: response document to the
French monograph and to the comments from Germany and the
United Kingdom, July, 29 1999. (Doc. SCP/FLURT/009).
8 Addendum to the evaluation table for
flurtamone doc. 7606/VI/97-Rev5, submitted by France,
January 17 2000 (Doc. SCP/FLURT/012).
9 Addendum to the monograph of the
active substance flurtamone; submitted by France, January,
17 2000. (Doc. SCP/FLURT/013).
10 Flurtamone: evaluation table doc.
7606/VI/97-Rev5, submitted by France, January 17 2000.
11 TFAA and TFMBA references as
submitted by Rhône-Poulence Agro after the submission of
the initial and reformatted EU registration dossier,
submitted by France February 4 2000. (Doc.
12 Flurtamone: Trifluoroacetic acid:
health effect risk assessment - March 3, 1999, Giovanna
Semino, Rhône-Poulenc Agro. (Doc. SCP/FLURT/016).
13 Letter from the Rapporteur Member
State (France) enclosing data relating to the metabolite
TFAA, March 9 1999. (Doc. SCP/FLURT/017).
14. Bott, T.L.; Standley, L.J. (1995):
Potential Effects of Trifluoroacetate on Freshwater Algal
Communities and Primary Productivity.
15. Bott, T.L.; Standley, L.J.: The
Effect of TFAA on Biological Processes in Streams
The Committee wishes to acknowledge the
contributions of the working groups that prepared the
initial draft opinion:
Environmental assessment WG: Prof. Hardy (Chairman)
and Committee members: Mr. Koepp, Prof. E.
Papadoupoulou-Mourkidou, Dr. Sherratt, Prof. Silva
Fernandes, invited experts: Dr. Boesten, Dr. Carter, Dr.
Forbes and Dr. Luttik.
Toxicology WG: Prof. Maroni (Chairman) and Committee
members: Dr. Delcour-Firquet, Prof. Leszkowicz, Dr. Meyer,
Dr. Moretto, Dr. Petzinger, Prof. Savolainen, Prof. Silva
Fernandes, Dr. Speijers and invited experts: Dr. Fait, Dr
Opinion of the Scientific Committee on
Plants regarding the inclusion of Flurtamone in annex 1 to
Directive 91/414/EEC concerning the placing of plant
protection products on the market (SCP/FLURT/004-Final) -
(Opinion expressed by the SCP on 18 December
OJ N° L 230, 19.08.1991, P. 1.
Organic carbon adsorption
No observed effect
Median effective concentration.
Lethal dose median.
Scientific Committee on Plants
Outcome of discussions
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