Reaction product of tetrahydro-2,5-dimethoxy furan, ethanol and water

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

yes

Remarks:

The temperature deviated partially from the temperature range set in the study plan representing a deviation from the study plan which is not considered to have an influence on the integrity of the results.

GLP compliance:

yes (incl. QA statement)

Remarks:

Fresenius

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At ambient temperature, protected from light
- Solubility and stability of the test substance in the solvent/vehicle: Amber liquid, indefinitely soluble at 20°C

Analytical monitoring:

yes

Details on sampling:

The level of TOC measured in freshly prepared test media samples and aged (after 3 days) test media samples, were compared against the carbon content of the test item measured.

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Desmodesmus subspicatus CHODAT
- Strain: 86.81
- Source: Sammlung von Algenkulturen, Pflanzenphysiologisches Institut der Universität Göttingen [SAG]
- Age of inoculum (at test initiation): Three days prior to starting the test, a pre-culture was inoculated using the algal stock culture.
- Method of cultivation: Three days before starting of the test, an algal pre-culture was made which was inoculated from an algal stock culture derived from the algal type culture collection Göttingen in order to guarantee sterile conditions at all. The pre-culture was incubated under the same conditions as the test solutions to be tested afterwards.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24.1 - 26.1 °C

pH:

8.03 - 9.51

Nominal and measured concentrations:

Recoveries of >69 % of the initial values measured at time t0 were obtained in the treatments at concentrations around the EC50 after 72 hr of incubation. The measured concentrations of the treatments after 72 hr deviated more than 20% from the nominal values. Based on this, the reported effect concentrations refer to mean measured concentrations (geometric mean) of the measured concentrations.

Details on test conditions:

TEST SYSTEM
- Fill volume: 50 mL
- Initial cells density: 3*10exp3 cells/mL
- No. of vessels per concentration (replicates): 7
- No. of vessels per control (replicates): 7; 3 treatments without any test item

GROWTH MEDIUM
- Standard medium used: yes

EFFECT PARAMETERS MEASURED :
- Determination of cell concentrations: photometrical measurement, 578 nm

TEST CONCENTRATIONS
- Test concentrations: 0.625, 1.24, 2.52, 5.00, 10.00 mg/L

Reference substance (positive control):

no

Remarks:

Within the analytical part, the test item served as a reference item

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

3.44 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CI 3.08-3.85 mg/L

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

10.81 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CI 8.79-13.18 mg/L

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.74 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Reported statistics and error estimates:

ToxRatPro Version 3.2.1

Inhibition Values

Nominal Concentra­tion of the Test Item [mg/L]	Growth Rates (day^-1)	Inhibition of the Growth Rate after 72hr [%]	Yield after 72hr^1)	Inhibition of the Yield after 72hr [%]
Control (0)	1.755	-	5.1*10^5	-
0.625	1.777	-1.3^2)	5.5*10^5	-6.9^2)
1.25	1.769	-0.8^2)	5.3*10^5	-4.4^2)
2.5	1.745	0.6	5.0*10^5	2.6
5.0	1.571	10.5	2.9*10^5	42.3
10.0	1.237	29.5	1.1*10^5	79.2

 

¹⁾Yield = Cell number at time t_72hr– cell number at time t₀;²⁾negative value indicates an activation

 

Concentrations of the Test Item during Incubation:

 

Nominal Conc. mg/L]	mg/L TOC net t0	mg/L TOC net t72hr	% of t0	Mean^1)Concentration TOC [mg/L]	Calculated mean^1)Concentration of the Test Item [mg/L]	% Recovery of the Nominal Concentrations
0	0	0	-	0	0	-
0.625	0.10	0.08	74.5	0.09	0.49	78.6
1.25	0.20	0.12	60.4	0.16	0.88	70.4
2.5	0.37	0.27	73.1	0.31	1.73	69.3
5	0.81	0.52	64.6	0.65	3.58	71.7
10	1.48	1.03	69.2	1.24	6.82	68.2

¹⁾Geometric mean concentration

Effect Concentrations on Basis of the Measured Concentrations:

 

Yield (0 - 72hr)                                                            EC10            1.85          95%-CL    lower            1.43                            upper            2.41                             EC20            2.41          95%-CL    lower            1.87                            upper            3.12                             EC50            4.00           95%-CL    lower            2.92                            upper            5.44                 Yield  LOEC            3.60                           NOEC            1.74 Section-by-section growth rate (0-72hr)                            EC10            6.77          95%-CL    lower            0.00                            upper             n.d.                             EC20            7.07          95%-CL    lower             n.d.                            upper             n.d.                             EC50           7.70          95%-CL    lower             n.d.                            upper             n.d.

Section-by-section growth rate (0-72hr)                           LOEC             n.d.                           NOEC             n.d.   Growth rate (0 - 72 hr)                                               EC10            3.44          95%-CL    lower            3.08                            upper            3.85                             EC20            5.10          95%-CL    lower            4.52                            upper            5.78                             EC50         10.81          95%-CL    lower            8.79                            upper          13.18     Growth rate  LOEC            3.60                           NOEC            1.74             n.d.: not determined due to mathematical reasons or inappropriate data

 

Validity criteria fulfilled:

yes

Conclusions:

For the growth rate, the EC10 was detemined to be 3.44 mg/L and the EC50 to be 10.81 mg/L.

Executive summary:

The toxicity of „Reaction Product from Tetrahydro-2,5-dimethoxyfurane, Ethanol and Water“ towards algae was tested according to OECD-Guideline No. 201, in the Version dated 23-March-2006. The toxic effect was investigated by determination of the inhibition of the growth rate of the algae and the yield during the exposure period of 72 hours. The test was performed using five concentrations in the range of 0.625 to 10 mg/L.

Description of key information

The toxicity of „Reaction Product from Tetrahydro-2,5-dimethoxyfurane, Ethanol and Water“ towards algae was tested according to OECD-Guideline No. 201, in the Version dated 23-March-2006. The toxic effect was investigated by determination of the inhibition of the growth rate of the algae and the yield during the exposure period of 72 hours. The test was performed using five concentrations in the range of 0.625 to 10 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

10.81 mg/L

EC10 or NOEC for freshwater algae:

3.44 mg/L