Sodium 4(or 5)-methyl-1H-benzotriazolide

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020-08-26 - 2021-09-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 309 (Aerobic Mineralisation in Surface Water - Simulation Biodegradation Test)

Version / remarks:

2004-04-13

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: Sponsor of Test, Batch 190733
- Purity, including information on contaminants, isomers, etc.: 99.98 % Tolyltriazole

Radiolabelling:

no

Oxygen conditions:

aerobic

Inoculum or test system:

natural water: freshwater

Details on source and properties of surface water:

- Details on collection (e.g. location, sampling depth, contamination history, procedure): river Rhine, Mumpf, Switzerland, 2020-09-04, 47°546024N / 07°931466E, sampling depth 5-10 cm, no effluent discharges
- Storage conditions: transportation in sealed containers, storage conditions not indicated
- Storage length: not indicated
- Temperature (°C) at time of collection: 19.8
- pH at time of collection: 8.08
- Redox potential (mv): 449.8
- Oxygen concentration (mg/l) initial/final: 8.98/9.64
- Dissolved organic carbon (mg/L): 25.7
- Total organic carbon (mg/L): 26.7
- Water sieved: yes
- Size of sieve used: 0.1mm sieve

Duration of test (contact time):

62 d

Initial conc.:

9.94 µg/L

Based on:

test mat.

Initial conc.:

100.15 µg/L

Based on:

test mat.

Details on study design:

TEST CONDITIONS
- Volume of test solution/treatment: 0.8mL of respective application solution/100mL water
- Solubilising agent (type and concentration if used): 50mL methanol/water (v/v; 4:1)
- Test temperature: 9.9 ± 0.4 °C
- pH: 7.89 (mean, test samples), 8.14 (mean, controls)
- pH adjusted: yes/no
- Suspended solids concentration: 0.222 mg Tolyltriazole/mL
- Continuous darkness: yes
- Any indication of the test material adsorbing to the walls of the test apparatus: no

TEST SYSTEM
- Culturing apparatus: 300mL Erlenmeyern flasks with 100mL natrual river surface water, gently sittred and incubated in aerobic flow-through system
- Number of culture flasks/concentration: 2
- Method used to create aerobic/oxygen conditions: flow-through system, adjusted by valve, gently stirred by bar magnet
- Measuring equipment: Packard liquid scintillation counters equipped with DPM and luminescence options (A2300 and A2700)

- Details of trap for CO2 and volatile organics if used: two absorption traps, one conteining ethylene glycol, the other 2N NaOH (in this sequence)

SAMPLING
- Sampling frequency: on day 0, 7, 15, 22, 36 and 62
- Sampling method used per analysis type: At each sampling interval, the oxygen content and pH were determined in in the samples to be harvested and in two control samples. Thereafter, the entire samples to be harvested were taken, the volumes of the water phases were recorded and directly analysed by LC-MS.
- Sampling reference control: At the respective sampling intervals, entire samples were taken. The volumes of the water phases and trapping solutions were recorded and aliquots analysed by LSC to determine dissolved radioactivity and volatile radioactivity in trapping solutions.
- Sample storage before analysis: generally analysed on the day of collection. If stored, then in fridge prior to LC-MS analysis

DESCRIPTION OF CONTROL AND/OR BLANK TREATMENT PREPARATION
CONTROL AND BLANK SYSTEM
- Benzoic application solution: prepared by diluting 0.110 mL of a benzoic acid solution (dissolved in ethanol) with 10 mL of water and submitted to ultrasonic treatment. Amount of benzoic acid = 0.874 mg/mL, based on the measured radioactivity (1’747’300 dpm per mL solution) and the specific activity of 33.33 MBq/mg
- Reference control: 1, 1.1mL of benzoic acid application solution in 100mL test water, at day 7 and 15
- Reference solvent control: 1, 1.1mL of benzoic acid application solution in 100mL test water
- Sterile control: 1, single untreated water samples, fortified with test item at selected concentrations on each sample day (except d0), worked-up in parallel with treated samples
- Blank control: 2, worked-up similarly to treated samples and served as blank control for analytical purposes
- Blank fortification: 1

STATISTICAL METHODS: Calculation with Microsoft Excel (Regression), MS performed by ESI (Electrospray Ionisation) in the positive ion full scan MS mode (Analyst 1.6.3)

Reference substance:

benzoic acid, sodium salt

Compartment:

natural water: freshwater

% Recovery:

92.7

Remarks on result:

other: for low dose samples

Compartment:

natural water: freshwater

% Recovery:

102.7

Remarks on result:

other: for high dose sterile samples

Compartment:

natural water: freshwater

% Recovery:

102.4

Remarks on result:

other: for high dose samples

Parent/product:

parent

Compartment:

water

Remarks on result:

not determinable

Remarks:

LC MS analysis of time 0 samples displayed mean recoveries of 100.8% (high dose), 99.3% (high dose, sterile) and 100.7% (low dose) of the amount applied. After 62 days of incubation, the mean amount of Tolyltriazole in the samples were 102.4%, 102.7% and 92.7% for the high dose, high dose sterile and low dose samples, respectively. The results showed that no significant degradation of Tolyltriazole was observed throughout the experiment.

Transformation products:

not specified

Validity criteria:

The total recovery (mass balance) at the end of the experiment should be between 90% and 110% for radiolabelled substances, whereas the initial recovery at the beginning of the experiment should be between 70% and 110% for non-labelled substances.

Observed value:

102.4%, 102.7% and 92.7% for the high dose, high dose sterile and low dose samples, respectively

Validity criteria fulfilled:

yes

Conclusions:

Tolytriazole was stable in natural surface water under aerobic conditions at 9.9 ± 0.4 °C for up to 62 days of incubation.

Executive summary:

Aerobic mineralization of Tolyltriazole in surface water was investigated under defined laboratory conditions in the dark. Tolyltriazole was applied at nominal rates of 100 and 10µg/L. Radiolabelled benzoic acid was used as reference substance to check microbial activity, which was confirmed within 15days of incubation.

Immediately after treatment (time 0), recoveries of 100.8%, 99.3% and 100.7% of the amount applied were measured in the water phase of the high dose, high dose sterile and low dose samples, respectively. After 62 days of incubation, the mean amount of Tolyltriazole in the samples were still 102.4%, 102.7% and 92.7% for the high dose, high dose sterile and low dose samples, respectively. The results showed that no significant degradation of Tolyltriazole was observed throughout the experiment.

Description of key information

In the available simulation study in surface water no degradation after 62 days was observed under test conditions. Consequently, no degradation products were found. Based on the findings a very persistent behaviour of Tolyltriazole in the environment is assumed. In addition, as the results from the simulation study are sufficient for the assessment according to Annex XIII of the REACH Regulation, no further study in sediment is necessary. For the exposure assessment a value of 1000 days is assumed for the calculations.

 

Key value for chemical safety assessment

Half-life in freshwater:

1 000 d

at the temperature of:

10 °C