Methanone, 1,1'-(1,4-phenylene)bis[1-(4-phenoxyphenyl)-

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Samples were taken and immediately analyzed.

Vehicle:

no

Details on test solutions:

All testing was performed using a synthetic medium prepared with Volvic® water and complemented as follow:

• 0.1 ml/L of B12 vitamin solution (1 µg/L)
• 0.1 ml/L of Na2SeO3.5H2O solution (6.7 µg/L)
• 1 ml/L of calcium / magnesium solution: Ca(NO3)2.4H2O : 208 mg/L and MgCl2.6H2O : 28 mg/L.

Chemical reagents used for the preparation of this dilution water were of “analytical grade”.

A number of preliminary trials were conducted with chemical analysis to develop a suitable test item preparation method. The trials investigated stirring period and filtration/centrifugation impact: it was found the test item stock solution should be prepared using a special temperature controlled glass-jacketed test vessel (around 3L of capacity) at a loading rate of 10 mg/L and kept under high speed stirring (around 1000 rpm) at ambient temperature during 48 hours. The aqueous phase was then drawn off as a clear solution after a resting period of around 30 minutes without agitation. The saturated solution was then centrifuged (3000 rpm, 10 minutes) to remove undissolved particles, as the filtration was found to retain the test item. Tests solutions were prepared from dilutions of this saturated solution.

All test solutions (including control) were renewed every day (including week-ends) from a stock solution freshly prepared as described above.

Test organisms (species):

Daphnia magna

Details on test organisms:

The test organisms used for this study was Daphnia magna Straus (Cladocera, Crustacea), clone 5, bred within the laboratory by acyclical parthenogenesis in a synthetic medium. D. magna cultures were fed with a mixture of the microalgae Chlorella vulgaris and Pseudokirchneriella subcapitata. The neonates used were less than 24h old at test initiation (selected by filtration) and were not first brood progeny. At the start of the experiment one D. magna neonate was added to each vessel. Test animals were fed a diet of around 0.1 - 0.2 mg of carbon per daphnid per day, in the form of a suspension of the algal strains Chlorella vulgaris (25%) and Pseudokirchneriella subcapitata (75%), except during the initial three to five days of culture when a slightly lower ration was given. The concentrated algal cell suspension was prepared by removing and centrifuging aliquots of algal culture and resuspending the algal pellets in small volumes of Volvic® water.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Test temperature:

19.3-20.4°C

pH:

7.3-8.4

Dissolved oxygen:

7.8-9.8 mg/L

Salinity:

Freshwater

Nominal and measured concentrations:

Nominal concentrations: 2.6, 6.4, 16.0, 40.0 and 100% of saturation (stock solution prepared at 10 mg/L and centrifuged), together with a control group
Measured concentrations (means of geometrical means): 0.70 ; 0.98 ; 1.52 ; 3.06 ; 6.55 µg/L

Details on test conditions:

The definitive test was performed as a dose-response test: daphnids were exposed at the following concentrations: 2.6, 6.4, 16.0, 40.0 and 100% of saturation, together with a control group. Test concentrations were arranged in a geometric series with a separation factor of 2.5. Ten replicate vessels were prepared at each concentration including the control group.
At the start of the experiment one D. magna neonate, less than one day old, was added to each vessel. Daphnia were fed as described above. The total test period was 21 days. All test solutions (including control) were renewed every day (including weekends). Samples for analysis were taken from all test concentrations and the control on 4 occasions throughout the test, on fresh and old solutions:
- at days 3 (fresh solutions) and 4 (old solutions)
- at days 8 (fresh solutions) and 9 (old solutions)
- at days 12 (fresh solutions) and 13 (old solutions)
- at days 15 (fresh solutions) and 16 (old solutions)

Every day, all parent animals were observed for immobilisation by gentle agitation of the test vessel. Any immobile animal within 15 seconds following agitation was considered as dead and discarded. The surviving parental Daphnia were transferred into fresh control or test media in a second set of vessels by means of a wide bore glass pipette. From the day of the first brood, all neonates (dead and alive), unhatched eggs or carapaces present in the expired media were counted daily and discarded. Any other abnormal observation was also recorded and reported.
pH and dissolved oxygen were measured daily in the fresh and old solutions in one of the vessels of each test group with surviving daphnids. The total hardness used to prepare test solutions was determined using a Hardness test kit (MColortest®, Merck). The temperature was continuously recorded throughout the test, in a flask maintained within the same conditions.

Reference substance (positive control):

no

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

3.06 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality: Number of living offspring produced per surviving parental animal {for Daphnia magna, TG 211}

Details on results:

Mobility inhibition
No immobile D. magna were recorded at all test concentrations or in the control. The lack of significant adult immobilisation in the test vessels compared with the control indicated that the test item has no effect on D. magna survival over a 21 day period, under test conditions. The no observed effect concentration (NOEC) was determined as greater than the highest tested concentration (i.e. 100% saturation).

Reproduction inhibition
A statistical analysis of the data shows a significant decrease of Daphnia reproduction in the saturated solution. The 21d-NOEC was 3.06 µg/L.

Age at First Reproduction
Offspring were observed in all treated group by Day 9. The test item has thus no effect on D. magna reproduction over a 21 day period, under test conditions, the no observed effect concentration (NOEC) was determined as greater than the highest tested concentration which was the highest concentration achievable in the test medium (i.e. 10.00 mg/L ).

Results with reference substance (positive control):

The sensitivity of the test system and the methodology are evaluated monthly by performing an acute Daphnia magna toxicity test on potassium dichromate. The nearest value of 24h-EC50 obtained on February 2019 was 0.79 mg/L. The ISO 6341 standard has a validity criterion specifying that the reference item 24h-EC50 must be in the 0.6 to 2.1 mg/L range.

Reported statistics and error estimates:

According to the OECD Guidance Document No 23 recommendations (2019), as measured concentrations in samples did not remain within 80-120% of nominal, the effect concentration were expressed relative to the time-weighted mean measured concentrations. For chemicals that could not be detected or quantified by the defined analytical method the following procedure was applied for the exposure concentration calculation:
- if the substance was not detected, the limit of detection was used
- when the substance was detected but not quantified, half of the limit of quantification was used

Three aberrant values were discarded (comparatively to expected values, considering the test item solubility in pure water (5 µg/L) and the dilution factor). All statistical analysis were conducted using the Software ToxRat V 3.3.0. EC10/EC50, LOEC and NOEC were determined for parent survival at the end of the test, number of living neonates produced by parent alive at the end of the test and time to first brood where relevant.

Table 1: raw data for controls

Controls	Parameter	J0	-	J8	J9	J10	J11	J12	J13	J14	J15	J16	J17	J18	J19	J20	J21	Sum
a	Liv. off.	0		0	13	0	0	23	0	0	28	0	0	33	0	0	20	117
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
b	Liv. off.	0		0	0	9	0	0	23	0	0	35	0	0	0	39	0	106
	Dead off.	0		0	0	0	0	0	3	0	0	0	0	0	0	0	0	3
	Egg	0		0	0	1	0	0	0	0	0	0	0	0	0	1	0	2
	Dead																	Alive
c	Liv. off.	0		0	15	0	0	24	0	0	29	0	0	33	0	0	35	136
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	1	0	0	0	1
	Dead																	Alive
d	Liv. off.	0		0	12	0	0	22	0	0	27	0	0	36	0	0	38	135
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
e	Liv. off.	0		0	0	9	0	0	0	14	0	0	19	0	0	28	0	70
	Dead off.	0		0	0	1	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
f	Liv. off.	0		0	9	0	0	17	0	0	30	0	0	31	0	0	30	117
	Dead off.	0		0	1	0	0	1	0	0	0	0	0	0	0	0	0	2
	Egg	0		0	0	0	0	0	0	0	0	0	0	1	0	0	2	3
	Dead																	Alive
g	Liv. off.	0		0	0	9	0	0	32	0	0	44	0	0	41	0	0	126
	Dead off.	0		0	0	1	0	0	1	0	0	0	0	0	0	0	0	2
	Egg	0		0	0	1	0	0	0	0	0	0	0	0	0	0	0	1
	Dead																	Alive
h	Liv. off.	0		0	11	0	0	21	0	0	29	0	0	33	0	0	32	126
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
i	Liv. off.	0		0	9	0	0	15	0	0	19	0	0	28	0	0	29	100
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	1	0	0	0	1
	Dead																	Alive
j	Liv. off.	0		0	9	0	0	21	0	0	31	0	0	38	0	0	33	132
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	2	0	0	0	0	0	0	0	0	0	2
	Dead																	Alive
Total of living offspring			1165		Mean of living offspring produced per parent					116.5
Total of dead offspring			11		Standard Deviation					20.2
Total of egg			10
Total of dead parent			0

Yellow cells indicates: dead neonates or eggs

Dead parents and living neonates produced by dead parents are not considered in the mean of living neonates produced per parent per treatment.

 

 

Table 2: raw data for 0.26 mg/L solution

0.26	Parameter	J0	-	J8	J9	J10	J11	J12	J13	J14	J15	J16	J17	J18	J19	J20	J21
a	Liv. off.	0		0	12	0	0	25	0	0	28	0	0	25	6	0	0
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead
b	Liv. off.	0		0	0	11	0	0	24	0	0	2	23	0	0	27	0
	Dead off.	0		0	0	3	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead
c	Liv. off.	0		0	7	0	0	21	0	0	26	0	0	33	0	0	30
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead
d	Liv. off.	0		0	8	0	0	19	0	0	20	0	0	27	0	0	32
	Dead off.	0		0	2	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead
e	Liv. off.	0		0	12	0	0	24	0	0	29	0	0	28	0	0	33
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead
f	Liv. off.	0		0	10	0	0	23	0	0	27	0	0	8	25	0	0
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead
g	Liv. off.	0		0	0	13	0	0	19	0	0	26	0	0	34	0	0
	Dead off.	0		0	0	2	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead
h	Liv. off.	0		0	10	0	0	18	0	0	24	0	0	30	0	0	38
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead
i	Liv. off.	0		0	8	0	0	27	0	0	34	0	0	33	0	0	37
	Dead off.	0		0	2	0	0	0	0	0	0	0	0	1	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead
j	Liv. off.	0		0	10	0	0	25	0	0	25	0	0	30	0	0	33
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead
Total of living offspring			1099		Mean of living offspring produced per parent					109.9
Total of dead offspring			13		Standard Deviation					17.5
Total of egg			0
Total of dead parent			0

 

Yellow cells indicates: dead neonates or eggs

Dead parents and living neonates produced by dead parents are not considered in the mean of living neonates produced per parent per treatment.

 

Table 3: raw data for 6.4% saturated solution

0.64	Parameter	J0	-	J8	J9	J10	J11	J12	J13	J14	J15	J16	J17	J18	J19	J20	J21	Sum
a	Liv. off.	0		0	12	0	0	33	0	0	34	0	0	35	3	0	0	117
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
b	Liv. off.	0		0	7	0	0	21	0	0	26	0	0	0	31	0	0	85
	Dead off.	0		0	3	0	0	0	0	0	0	0	0	0	0	0	0	3
	Egg	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Dead																	Alive
c	Liv. off.	0		0	13	0	0	26	0	0	33	0	0	37	0	0	42	151
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
d	Liv. off.	0		0	12	0	0	27	0	0	30	0	0	34	0	0	40	143
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
e	Liv. off.	0		0	8	0	0	15	0	0	22	0	0	24	0	0	2	71
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
f	Liv. off.	0		0	13	0	0	26	0	0	29	0	0	0	37	0	0	105
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	1	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
g	Liv. off.	0		0	14	0	0	28	0	0	29	0	0	37	0	0	37	145
	Dead off.	0		0	2	0	0	0	0	0	0	0	0	0	0	0	0	2
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
h	Liv. off.	0		0	12	0	0	21	0	0	27	0	0	37	0	0	38	135
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
i	Liv. off.	0		0	10	0	0	25	0	0	27	0	0	34	0	0	34	130
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
j	Liv. off.	0		0	5	0	0	19	0	0	24	0	0	25	0	0	32	105
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Dead																	Alive
Total of living offspring			1187		Mean of living offspring produced per parent					118.7
Total of dead offspring			8		Standard Deviation					26.9
Total of egg			2
Total of dead parent			0

 

Yellow cells indicates: dead neonates or eggs

Dead parents and living neonates produced by dead parents are not considered in the mean of living neonates produced per parent per treatment.

 

Table 4: raw data for 16% saturated solution

1.60	Parameter	J0	-	J8	J9	J10	J11	J12	J13	J14	J15	J16	J17	J18	J19	J20	J21	Sum
a	Liv. off.	0		0	0	0	10	0	0	16	0	0	21	0	0	29	0	76
	Dead off.	0		0	0	0	0	0	0	0	0	0	1	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
b	Liv. off.	0		0	6	0	0	14	0	0	24	0	0	0	27	0	0	71
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	1	0	0	0	0	0	0	0	0	0	1
	Dead																	Alive
c	Liv. off.	0		0	15	0	0	23	0	0	32	0	0	35	0	0	38	143
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	1	0	0	0	0	0	0	1
	Dead																	Alive
d	Liv. off.	0		0	9	0	0	22	0	0	29	0	0	31	0	0	31	122
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
e	Liv. off.	0		0	21	0	0	35	0	0	38	0	0	0	38	0	0	132
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
f	Liv. off.	0		0	14	0	0	29	0	0	32	0	0	38	0	0	39	152
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
g	Liv. off.	0		0	14	0	0	28	0	0	30	0	0	33	0	0	35	140
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
h	Liv. off.	0		0	0	12	0	0	16	0	0	25	0	0	33	0	0	86
	Dead off.	0		0	0	2	0	0	0	0	0	0	0	0	0	0	0	2
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
i	Liv. off.	0		0	9	0	0	18	0	0	22	0	0	32	0	0	34	115
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
j	Liv. off.	0		0	0	0	0	0	2	0	0	0	21	0	0	22	0	45
	Dead off.	0		0	0	0	0	0	4	0	0	0	2	0	0	0	0	6
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	1	0	1
	Dead																	Alive
Total of living offspring			1082		Mean of living offspring produced per parent					108.2
Total of dead offspring			12		Standard Deviation					36.3
Total of egg			3
Total of dead parent			0

 

Yellow cells indicates: dead neonates or eggs

Dead parents and living neonates produced by dead parents are not considered in the mean of living neonates produced per parent per treatment.

 

Table 5: raw data for 40% saturated solution

4.00	Parameter	J0	-	J8	J9	J10	J11	J12	J13	J14	J15	J16	J17	J18	J19	J20	J21	Sum
a	Liv. off.	0		0	8	0	0	22	0	0	28	0	0	33	0	0	35	126
	Dead off.	0		0	2	0	0	1	0	0	0	0	0	1	0	0	2	6
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
b	Liv. off.	0		0	9	0	0	24	0	0	36	0	0	39	0	0	0	108
	Dead off.	0		0	2	0	0	1	0	0	0	0	0	0	0	0	0	3
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
c	Liv. off.	0		0	10	0	0	26	0	0	27	0	0	39	0	0	32	134
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
d	Liv. off.	0		0	12	0	0	26	0	0	28	0	0	33	0	0	31	130
	Dead off.	0		0	1	0	0	0	0	0	0	0	0	0	0	0	1	2
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
e	Liv. off.	0		0	12	0	0	26	0	0	33	0	0	31	0	0	37	139
	Dead off.	0		0	2	0	0	0	0	0	0	0	0	0	0	0	0	2
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
f	Liv. off.	0		0	12	0	0	26	0	0	0	0	0	0	14	0	0	52
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	1	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
g	Liv. off.	0		0	9	0	0	29	0	0	31	0	0	32	3	0	1	105
	Dead off.	0		0	1	0	0	1	0	0	0	0	0	1	0	0	0	3
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
h	Liv. off.	0		0	13	0	0	25	0	0	28	0	0	34	0	0	37	137
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
i	Liv. off.	0		0	7	0	0	21	0	0	33	0	0	33	0	0	30	124
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
j	Liv. off.	0		0	6	0	0	19	0	0	28	0	0	31	0	0	34	118
	Dead off.	0		0	3	0	0	2	0	0	0	0	0	0	0	0	1	6
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
Total of living offspring			1173		Mean of living offspring produced per parent					117.3
Total of dead offspring			24		Standard Deviation					25.7
Total of egg			0
Total of dead parent			0

 

Yellow cells indicates: dead neonates or eggs

Dead parents and living neonates produced by dead parents are not considered in the mean of living neonates produced per parent per treatment.

 

Table 6: raw data for 100% saturated solution

10.00	Parameter	J0	-	J8	J9	J10	J11	J12	J13	J14	J15	J16	J17	J18	J19	J20	J21	Sum
a	Liv. off.	0		0	8	0	0	17	0	0	20	0	0	20	6	0	1	72
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
b	Liv. off.	0		0	7	0	0	14	0	0	23	0	0	22	3	0	0	69
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
c	Liv. off.	0		0	8	0	0	19	0	0	25	0	0	29	0	0	26	107
	Dead off.	0		0	4	0	0	0	0	0	0	0	0	2	0	0	1	7
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
d	Liv. off.	0		0	13	0	0	31	0	0	33	0	0	0	35	0	0	112
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
e	Liv. off.	0		0	8	0	0	15	0	0	15	1	0	0	26	0	0	65
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
f	Liv. off.	0		0	5	0	0	23	0	0	30	0	0	0	31	0	0	89
	Dead off.	0		0	2	0	0	0	0	0	0	0	0	0	0	0	0	2
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
g	Liv. off.	0		0	10	0	0	24	0	0	26	0	0	37	0	0	0	97
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
h	Liv. off.	0		0	14	0	0	25	0	0	28	0	0	0	33	0	0	100
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
i	Liv. off.	0		0	12	0	0	22	0	0	28	0	0	8	22	0	0	92
	Dead off.	0		0	0	0	0	0	0	0	0	0	0	1	0	0	0	1
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																	Alive
j	Liv. off.	0		0	6	0	0	21	0	0	18	0	1	0	28	0	0	74
	Dead off.	0		0	1	0	0	1	0	0	1	0	0	0	0	0	0	3
	Egg	0		0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Dead																		Alive
Total of living offspring			877		Mean of living offspring produced per parent					87.7
Total of dead offspring			13		Standard Deviation					16.7
Total of egg			0
Total of dead parent			0

 

Yellow cells indicates: dead neonates or eggs

Dead parents and living neonates produced by dead parents are not considered in the mean of living neonates produced per parent per treatment.

Table7: Reproduction test: exposure concentrations used for statistical analysis 

 

Test solution Nominal conc. (mg/L)	Test item measured concentrations(µg/L)												Exposure conc. (µg/L)*
	Occasion 1			Occasion 2			Occasion 3			Occasion 4
	fresh	old	% dev. 24h	fresh	old	% dev. 24h	fresh	old	% dev. 24h	fresh	old	% dev. 24h
0.26	0.23	0.23	0.0	0.39	0.62	58.6	0.99	1.83	84.7	0.39	1.19	204.6	0.70
0.64	1.20	0.34	-72.0	0.39	1.22	211.6	1.21	2.03	67.8	0.46	1.63	257.7	0.98
1.60	0.98	0.93	-5.6	0.76	1.85	144.0	1.56	2.68	71.6	1.24	2.63	112.9	1.52
4.00	2.49	2.78	11.6	1.61	3.43	112.7	2.44	3.96	62.0	3.38	4.80	42.0	3.06
10.00	discarded			4.00	6.94	73.4	4.95	6.47	30.8	7.77	9.54	22.9	6.55

*concentrations expressed as time-weighted mean measured concentrations determined according to the formula described in OECD (2019).

Validity criteria fulfilled:

yes

Conclusions:

No effect was observed on parent mortality or age at first brood. A significant reduction of neonate production was observed at the highest tested concentration. NOEC was 3.06 µg/L for this endpoint.

Executive summary:

This study was designed to determine the effects of [4 -(4 -phenoxybenzoyl)phenyl]-(4 -phenoxyphenyl)methanone on Daphnia magna reproduction and survival in a 21 days test according to OECD TG 211 (2012). Daphnia magna were exposed to solutions of the test item at 2.6%, 6.4%, 16%, 40% and 100% saturation in test medium, together with a control group. The test solutions (including control) were renewed daily throughout the test, including weekends. The test item stock solution was prepared at a loading rate of 10 mg/L. This solution was stirred during approximately 48 hours then drawn off as a clear solution after a resting period of 30 min without agitation. This saturated solution was then further diluted to obtain each test solution (spacing factor of 2.5).

Ten replicate test vessels were prepared for the control and for each test concentration. A single juvenile Daphnia magna (<24 hours old selected by filtration) was added to each test vessel. On renewal occasion, parental animals were transferred into freshly prepared test medium. Any juveniles remaining in old test media were counted and the number of juveniles produced per parental animal on any day during the 21-day study duration was recorded. The time of the first production of young, the number of young born, immobility and other signs of toxicity observed were compared to a control group.

Chemical analysis was made on fresh and old solutions throughout the test. A decline in measured test concentration of the aged test solutions was observed. Based on these results, the exposure concentrations were based on the geometric means of measured concentrations.

There were no immobile parent Daphnia magna in the control group and in all treatment groups. In this study, the lowest NOEC (3.06 mg/L) was observed for the mean number of neonates produced per surviving parent.

The definitive test met the validity criteria of the test guideline detailed as follows (for the control group):

               § the mortality of the parent animals (femaleDaphnia) did not exceed 20% at the end of the test (0%);

§ the mean number of living neonates produced per parent animal surviving at the end of the test is > 60 (116.5)

 

In addition the CV (17.4%) of the mean number of living neonates produced per control parent animal surviving at the end of the test was lower than the threshold recommended by the OECD 211 guideline (25%).

Description of key information

This study was designed to determine the effects of the registered substance on Daphnia magna reproduction and survival in a 21 days test according to OECD TG 211 (2012). Daphnia magna were exposed to solutions of the test item at 2.6%, 6.4%, 16%, 40% and 100% saturation in test medium, together with a control group. The test solutions (including control) were renewed daily throughout the test, including weekends. Ten replicate test vessels were prepared for the control and for each test concentration. A single juvenile Daphnia magna was added to each test vessel. On renewal occasion, parental animals were transferred into freshly prepared test medium. Any juveniles remaining in old test media were counted and the number of juveniles produced per parental animal on any day during the 21-day study duration was recorded. The time of the first production of young, the number of young born, immobility and other signs of toxicity observed were compared to a control group. There were no immobile parent Daphnia magna in the control group and in all treatment groups. In this study, the lowest NOEC (3.06 µg/L) was observed for the mean number of neonates produced per surviving parent. The definitive test met the validity criteria of the test guideline.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

3.06 µg/L