1,3,5-Triazin-2-amine, 4-methoxy-6-(trifluoromethyl)-

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

effects on growth of an additional algal species

Type of information:

experimental study

Adequacy of study:

other information

Study period:

1999

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Data source

Reference

Reference 1

Title:

Unnamed

Year:

1999

Reference 2

Reference Type:

other: Draft Renewal Assessment Report under Regulation (EC) 1107/2009

Title:

Draft Renewal Assessment Report under Regulation (EC) 1107/2009 - Tritosulfuron

Year:

2018

Bibliographic source:

Draft Renewal Assessment Report under Regulation (EC) 1107/2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

No deviations from the current guideline.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

4-methoxy-6-(trifluoromethyl)-1,3,5-triazin-2-amine

EC Number:

610-962-9

Cas Number:

5311-05-7

Molecular formula:

C5H5F3N4O

IUPAC Name:

4-methoxy-6-(trifluoromethyl)-1,3,5-triazin-2-amine

Sampling and analysis

Analytical monitoring:

yes

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

Unicellular fresh water green alga, Pseudokirchneriella subcapitata (syn.: Selenastrum capricornutum), SAG 61.81; stock obtained from „Sammlung Algenkulturen“, Göttingen (FRG), cultures maintained in-house.

Study design

Test type:

static

Total exposure duration:

72 h

Test conditions

Test temperature:

22 °C – 23 °C

pH:

8.0 (at test initiation)

Nominal and measured concentrations:

Control, 10, 18, 32, 56 and 100 mg/L (nominal).

Details on test conditions:

Static system; test duration 72 hours; 5 test concentrations, each with 5 replicates plus a control with 10 replicates; daily assessments of growth. continuous light, light intensity 8000 lux.

Results and discussion

Effect concentrations

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Any other information on results incl. tables

Tables are attached separately

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Conclusion of the DAR (2001-2007): 72 h EC50 >100 mg BH 635-5 /L

Executive summary:

Analytical measurements: Analytical verification of test substance concentrations was carried out in each concentration at the beginning and at the end of the test after 72 hours. At study start the analyses yielded 101.0% - 105.4% of the nominal values and at the end of the study between 103.1% and 106.6% of the nominal concentrations were detected.

Biological results: No morphological effects on the algae could be observed.

In a 72-hour algae test with Pseudokirchneriella subcapitata the ErC10 of BH 635-5 was determined to be > 100 mg/L (nominal).

 

This older study was not deviating from the recommendation in the current OECD TG 201 to use at least 6 control replicas as there were 10 control replicas used. The average specific growth rate of the control cultures over 3 days was 1.250 day-1, thus exceeding validity criterion of 0.92 day-1 (increase by more than a factor of 16). The study summary does not include parameters which would allow a proper evaluation of the validity of the study according to the current OECD TG 201, in particular:
1. Mean coefficient of variation for section-by-section specific growth rates for control replicates
2. The coefficient of variation of average specific growth rates for control replicates
Section-by-section specific growth rates are reported in the original report as 0.971 for 0-24h, 1.389 for 24-48h and 1.390 for 48-72h. This results in a mean coefficient of variation of 19.5%, fulfilling the validitiy criterion <35%. The coefficient of variation of average specific growth rates based specific growth rates over 0-72h reported in the original report is calculated as 2.0, fulfilling the validitiy criterion <7% for tests with Pseudokirchneriella subcapitata. There is a dose-response observed for effects on biomass which allows for a reliable estimate of the EC10 at 71 mg BH 635-5 /L. Due to the lack of a dose-response it is not possible to provide a meaningful EC10 for effects on growth rate. NOEC values are not reported in the original study report. The study is valid and acceptable for use in risk assessment. We agree with the endpoint relevant for risk assessment,
72 h ErC50/ EbC50 >100 mg BH 635-5 /L
72 h ErC10 >100 mg BH 635-5 /L
72 h EbC10 71mg BH 635-5 /L