Ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

5 August 2013 - 23 August 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

adopted 13th April 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

30 May 2008 (O.J. L 142 of 31.5.2008)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Chemical name Phosphinic acid, phenyl(2,4,6-trimethylbenzoyl)-,ethyl ester
Empirical formula C18H21O3P
Physical form Liquid, viscous
Water solubility Insoluble at 20°C: 35 mg/l
Purity (1H-NMR) 95.7 g/100 g
Purity (GC) 97.0 area-% (DB-1) – 97.8 area-% (DB-1701)
Test substance storage At room temperature, protected from light

Analytical monitoring:

yes

Details on sampling:

HPLC analyses of the test substance concentrations was conducted in the definitive test at the beginning and after 24 and 48 h of exposure.

Vehicle:

no

Details on test solutions:

The loadings of the test material were prepared by adding the respective amounts of an acetonic stock solution to empty glass vessels. After complete evaporation of the solvent, the aerated Daphnia medium (Tables 1 and 2) was added, moderately stirred for 24 h, followed by filtration (MILLIPORE AP15 glass fiber filter). The resulting saturated solutions were used in the test.

Test organisms (species):

Daphnia magna

Details on test organisms:

Test organism: Daphnia magna (Straus, 1820)

Breeding: Parental and young Daphnia held in 4 l glass aquaria (3 l medium) at 20 ± 2 °C

Illumination: 16 h per day

Medium: Continuously aerated Elendt M4 medium; prepared with deionised water (conductivity <1.5 µS/cm)

Feed: Suspension of Desmodesmus subspicatus in Elendt M4 medium with an optical density OD680 of about 15 units Frequency of feeding: 400 μl per Daphnia per day, except on weekends

Control of sensitivity: Acute reference test with potassium dichromate conducted twice a year

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

Total hardness (as sum of Ca and Mg): 2.52 mmol/l
Carbonate hardness: 0.32 mmol/l

Test temperature:

22 °C

pH:

control: 7.3 - 7.4
exposure groups: 7.3 - 7.5

Dissolved oxygen:

control: 8.2
exposure groups: 7.5 - 8.1

Salinity:

Not reported - Freshwater

Conductivity:

Not reported - Freshwater

Nominal and measured concentrations:

Based on the results of the range finding test, the definitive test was performed at the following loading rates: 6.25, 12.5, 25.0, 50.0 and 100 mg/l

Details on test conditions:

Test vessel 100 ml flasks, all-glass, with 50 ml of test medium

Test medium Elendt M4 medium (Tables 1 and 2); prepared with deionised water (conductivity <1.5 μS/cm)

Number of Daphnia 40 individuals per test concentration, 20 per vessel

Age Less than 24 h

Light 16 h photoperiod a day, supplied by overhead white fluorescent tubes

Temperature (target) 20 ± 2 °C (temperature-controlled room)

Test type Static exposure conditions

Test duration 48 h

For each test series, the following number of test flasks was used:

Test suspension (Tn); containing test medium, test substance, two replicate samples with 20 Daphnia each

Blank control (Bn); containing test medium, three replicate samples with 20 Daphnia each

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

1.55 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Lower 95%-cl 6.02; Upper 95%-cl 9.67

Duration:

48 h

Dose descriptor:

other: EC20

Effect conc.:

1.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Lower 95%-cl 7.59; Upper 95%-cl 11.2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.26 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Lower 95%-cl 11; Upper 95%-cl 14.8

Details on results:

HPLC analysis of Lucirin TPO-L was performed at the beginning of the exposure, after 24 h and at the end of the exposure (48 h). The analysis revealed that the test substance was only partially soluble: measured concentrations at the beginning of
the exposure were 1.10, 3.37, 8.36, 16.3 and 32.7 mg/l.

The test concentrations could satisfactorily be maintained over the whole period of exposure: geometric mean concentrations after 24 (GM0-24h) and 48 h (GM0-48h) of exposure were 1.21, 3.10, 7.52, 17.9 and 28.8 mg/l (110, 92, 90, 110 and 88% of initial concentration, respectively) and 1.00, 2.85, 6.75, 16.2 and 29.2 mg/l (90, 85, 81, 100 and 89% of initial concentration, respectively). The effective concentrations (EC10, EC20, EC50) of Lucirin TPO-L to Daphnia magna were assessed based on the geometric mean (GM) concentrations.

Results with reference substance (positive control):

The EC50 for the control of sensitivity for 24 h of exposure with potassium dichromate was estimated to be 0.8 mg/l (data from 17 July 2013). The resulting EC50 value of the reference item was within the recommended range of 0.6 - 2.1 mg/L according to OECD Guideline 202.

Reported statistics and error estimates:

95% confidence limits reported

Validity criteria fulfilled:

yes

Conclusions:

The 48 hour EC50 of the test material to Daphnia magna was determined to be 2.26 mg/l under the conditions of the test.

Executive summary:

The effective concentrations (EC10, EC20, EC50) of Lucirin TPO-L to Daphnia magna were investigated under static exposure conditions over a period of 48 h. 40 individual Daphnia divided into 2 test vessels were exposed to the test substance.  

The applied loading rates were 6.25, 12.5, 25.0, 50.0 and 100 mg/l. The loadings of the test material were prepared by adding the respective amount of an acetonic stock solution to an empty glass vessel. After complete evaporation of the solvent, the aerated Daphnia medium was added, moderately stirred for a minimum of 24 h, followed by filtration. The resulting saturated solutions were used in the test.

HPLC analysis of Lucirin TPO-L was performed at the beginning of the exposure, after 24 h and at the end of the exposure (48 h). The analysis revealed that the test substance was only partially soluble: measured concentrations at the beginning of the exposure were 1.10, 3.37, 8.36, 16.3 and 32.7 mg/l. The test concentrations could satisfactorily be maintained over the whole period of exposure: geometric mean concentrations after 24 (GM0-24h) and 48 h (GM0-48h) of exposure were 1.21, 3.10, 7.52, 17.9 and 28.8 mg/l (110, 92, 90, 110 and 88% of initial concentration, respectively) and 1.00, 2.85, 6.75, 16.2 and 29.2 mg/l (90, 85, 81, 100 and 89% of initial concentration, respectively). The effective concentrations (EC10, EC20, EC50) of Lucirin TPO-L to Daphnia magna were assessed based on the geometric mean (GM) concentrations.

The results are summarized in the following table showing ECx values and 95% confidence limits (cl):

Parameter	EC10	EC20	EC50
24 h exposure
GM0-24 h conc. [mg/l]	8.08	9.6	12.9
Lower 95%-cl	6.02	7.59	11
Upper 95%-cl	9.67	11.2	14.8
Chi2	0.063 Regression model: Logit
Intercept a	-12
Slope b	10.8
48 h of exposure
GM0-48 h conc. [mg/l]	1.55	1.9	2.69
Lower 95%-cl	1.01	1.39	2.27
Upper 95%-cl	1.92	2.26	3.12
Chi2	2.13 Regression model: Logit
Intercept a	-3.94
Slope b	9.17

Description of key information

The study was conducted to recognised testing guidelines, and with GLP certification.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.26 mg/L