Propionaldehyde, reaction product with formaldehyde

Sediment toxicity

Link to relevant study record(s)

Reference

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 02 October 2020 to 26 April 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 218 (Sediment-Water Chironomid Toxicity Test Using Spiked Sediment)

Version / remarks:

Deviation from study plan: a typo in the study plan. the dilution factor 2 was used to calculate the lower test concentrations (276 mg test item/kg dry sediment divided by 2=138mg test item/kg dry sediment). This deviation had no impact of the integrity and quality of the study.

Deviations:

yes

Remarks:

Deviation had no impact of the integrity and quality of the study.

GLP compliance:

yes

Specific details on test material used for the study:

Sponsor Code: ZS-Nr. 0117
Chemical Name: (IUPAC) Propionaldehyde, reaction product with formaldehyde
EC Number: 701-281-9
CAS Number: Not available
Molecular Formula: The substance is a UVCB. Molecular formula of the major constituent is C5H10O3.
Molecular Weight: The substance is a UVCB. Molecular weight of the major constituent is 118.1326 g/mol.
Purity: The substance is a UVCB, therefore by definition 100% pure. It contains 54.7% water and 45.3 % of constituent as ‘ai’ (active ingredient).
Appearance and Colour: Colorless liquid
Density: 1.29 g/cm3 at 20 °C
Water Solubility: 1003 g/L at 20 °C
Expiration Date: May 05, 2022
Storage Conditions: Room Temperature approx. 20 °C, not above 40 °C.
IES Code: 12099

Analytical monitoring:

yes

Remarks:

The test item was used as analytical standard.

Details on sampling:

The determined concentrations in sediment samples two days before the start of the test subsequent to their preparation.

Vehicle:

no

Details on sediment and application:

An artificial (formulated) sediment was used. The artificial sediment was prepared on the basis of dry weights as follows (expressed in % distribution):
- Sphagnum peat: 5 %
(air dried, very finely ground to ≤ 1 mm)
organic carbon content 45.9 %)
- Kaolin clay: 20 %
(content of kaolinite: 52 %
content of Al2O3: 31.5 %)
- Sand (Quarzsand A 0.06 – 0.25 mm): 75 %
Size analysis
0.25 mm 1.5 %
0.18 mm 16.5 %
0.125 mm 54.5 %
0.09 mm 23.5 %
<0.09 mm 4.0 %
- Calcium carbonate (CaCO3): 0.45 %

The total organic carbon (TOC) in this artificial sediment was 2.1 % (based on dry weight).

All dry constituents were weighed in the correct portions. The finely ground peat was moistened with purified water by intense mixing using an ultra-turrax and then gentle stirring for three days at room temperature in the dark. The pH of the peat suspension was 5.7 at the start of moistening. After the moistening procedure the pH was 5.9. Then all constituents (and some CaCO3) were thoroughly blended in a laboratory mixer to give a homogeneous wet sediment. With the added purified water a sufficient moisture of the final sediment mixture was obtained (i.e. 46 % of the dry weight sediment).
A final sediment sample of about 10 g was shaken with 25 mL of a 1M KCl solution for 30 minutes and then the pH was measured in this suspension. The pH of the final mixture of sediment was 7.3. The artificial sediment was checked for absence of chemical contamination. The following parameters were analyzed in a representative sample of the artificial sediment: heavy metals (Pb, Cd, Cr, Cu, Mo, Ni, Hg and Zn) and pesticides.

Test organisms (species):

Chironomus riparius

Details on test organisms:

The study was performed with larvae of the midge species Chironomus riparius successfully maintained at IES Ltd Laboratories, under similar temperature and light conditions and in the same type of test water as used in the test.
Only fresh egg masses were used as a source for the test animals. At the date when the test animals were placed into the test beakers, the larvae were 2 days old.

Study type:

laboratory study

Test type:

static

Water media type:

freshwater

Type of sediment:

artificial sediment

Limit test:

no

Duration:

28 d

Remarks:

5 days after emergence of the last test animal in the controls

Hardness:

Day 0: 230 mg/l (Control), 230 mg/l (1000 mg a.i./kg dry sediment)
Day 28: 340 mg/l (Control), 340 mg/l (1000 mg a.i./kg dry sediment)

Test temperature:

19.2-20.1 °C during the experiment. The water temperature differed by less than 1.0 °C between beakers at any time during the test. The test was performed in a temperature-controlled room.

pH:

The formulated (wet) sediment had a pH of 7.3 at test start. The pH of the test water was 7.7 in all test vessels at the start and between 8.3 and 8.4 at the end of the test.

Dissolved oxygen:

7.8 mg/L (= 84 % oxygen saturation value),

Ammonia:

Day 0: 0.605 mg/L (Control), 0.458 mg/L (1000 mg a.i./kg dry sediment)
Day 28: 45.1 mg/L (Control), 48.1 mg/L (1000 mg a.i./kg dry sediment)

Conductivity:

approximately 710 µS/cm.

Nominal and measured concentrations:

The following five nominal test concentrations of Propionaldehyde, reaction product with formaldehyde were tested: 1381, 276, 552, 1104 and 2208 mg test item/kg dry sediment, corresponding to 62.5, 125, 250, 500 and 1000 mg a.i./kg dry sediment.

Details on test conditions:

Exposure duration: 28 days after introduction of the test organisms (5 days after emergence of the last test animal in the controls).
Water temperature: 19.2-20.1 °C during the experiment. The water temperature differed by less than 1.0 °C between beakers at any time during the test.
The test was performed in a temperature-controlled room.
Aeration: During the whole study (with exception of the period of 3.5 hours after the introduction of the larvae) the water in the water-sediment systems was gently aerated through a glass Pasteur pipette, fixed above the sediment layer.
pH: The formulated (wet) sediment had a pH of 7.3 at test start. The pH of the test water was 7.7 in all test vessels at the start and between 8.3 and 8.4 at the end of the test.
Light conditions: A 16-hour light to 8-hour dark photoperiod with a 30 minute transition period between light and darkness. Light intensity during the light period was within the range of approximately 798–965 Lux (measured approximately at water surfaces of the test beakers).
Feeding: Tetra Min fish food (TETRA MIN Hauptfutter, supplied by Tetra GmbH, 49324 Melle, Germany) was used as food for the larvae. The fish food flakes were finely ground and suspended in test water.
Food was added at least three times per week until day 26, when most of the adult midges had emerged. The following amounts of dry Tetra Min were fed per vessel and day:
0.467 ml/vessel = 23 mg Tetra Min/vessel on days 0, 2, 5, 21, 23 and 26.
0.934 ml/vessel = 47 mg Tetra Min/vessel on days 7, 9, 12, 14, 16 and 19.

Reference substance (positive control):

no

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

31.5 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

emergence rate

Remarks on result:

other: corresponding to 69.6 mg test item /kg dry sediment

Key result

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

> 31.5 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

emergence rate

Remarks on result:

other: corresponding to 69.6 mg test item /kg dry sediment

Details on results:

NON GLP RESULTS OF THE RANGE FINDING TEST
A range finding test with the following nominal test concentrations was conducted: 1.0, 10 and 100 mg a.i./kg dry sediment corresponding to 2.21, 22.1 and 221 mg test item/kg dry sediment.
Additionally, a control was run in parallel. For all treatments two replicates with 20 test organisms each were prepared. The chironomids were exposed to the test item for 28 days.
No toxic effects were observed at 100 mg a.i./kg dry sediment in the range finding test. The results of the range finding test were confirmed by the main test.

ANALYTICAL RESULTS
The analytically measured concentrations of Propionaldehyde, reaction product with formaldehyde in the application solution samples ranged from 90 to 106 % of the nominal values. This confirmed the correct preparation of the application solutions.
The total recovery of the nominal amounts of applied test item found in the sediment immediately after application (Day-2) ranged from 81 % to 93 % in all tested concentrations. Thus, the correct application of the test item could be verified.
For the quantification of the test item concentrations in the three compartments water, pore water and sediment, the concentration of the active ingredient was analytically determined in the lowest and highest tested concentration (62.5 and 1000 mg a.i./kg dry sediment).
During the equilibration (Day -2 to 0) and the test period (Day 0 to 28), the test item concentration in the three compartments rapidly decreased. The total recovery of the nominal amounts of applied test item found in the three compartments ranged from 25 to 36 % at test start (Day 0). After 7 and 28 days of the exposure no test item were determined in the concentration of 62.5 mg a.i./kg. In the concentration of 1000 mg a.i./kg, 13 and 0.2 % of the total nominal amount were determined after 7 and 28 days, respectively.
The part of test item which was transferred to water and pore water and the relationship of the total determined test item in the three compartments are presented in Table 1.
The mean measured concentration of the highest nominal active ingredient concentration of 1000 mg a.i./kg dry sediment (corresponding to 2208mg test item/kg dry sediment) was calculated as time-weighted mean over measurements on Day 0, 7 and 28. The highest tested mean measured concentration corresponds to 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment.

BIOLOGICAL RESULTS:
The biological test results were based on the mean measured concentration of the active ingredient and the test item in the dry sediment, since the test item decreased during the test.
-Emergence Ratio:
The numbers of fully emerged midges per test vessel on each inspection day were evaluated. The values were listed separately for males, females and for pooled sexes in the original report. The emergence ratio per vessel in the control was 99 % (thus fulfilling the guideline validity criterion of ≥ 70 %).
The calculated mean emergence ratios for pooled sexes are given in Table 2. The test item had no statistically significant inhibitory effect on the emergence ratios of pooled sexes during the test period of 28 days up to and including the highest mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment (results of Dunnett’s t-test,  = 0.05, one-sided greater).
-Development rate:
The calculated mean development rates for both sexes are given in Table 3. The emergence of adult midges in the control occurred between Days 13 and 23 after the insertion of the larvae into the test vessels, i.e. in the requested time frame between 12 and 23 days (Table 1). One single female midge emerged on Day 24 in the control (replicate 1). This single midge is not seen to have an overall significant impact on the outcome of the study itself and can still be counted as biological variance within a living test system setup.
The mean development rates of males and fimaled were not statistically significantly lower than in the control up to and including the highest mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment, according to a Dunnett’s and Welch t-test after Bonferroni –Holm t-test ( = 0.05, one-sided smaller), respectively.
The 28-day EC15 and EC50 values could not be calculated due to the absence of toxicity of the test item.
-Symptoms of toxicity:
No symptoms of toxicity were observed at the larvae, pupae and emerged midges during the study.
-NOEC and LOEC:
Taking into account the emergence ratios and development rates of Chironomus riparius and observations of any toxicity symptoms, the overall 28-day NOEC of Propionaldehyde, reaction product with formaldehyde in this water-sediment study was equal to or higher than the highest tested mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment.
The 28-day LOEC was higher than the mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment.
-Water parameters:
During the test period, the pH values in the test media ranged from 7.7 to 8.4 (Table 4). The dissolved oxygen concentrations were at least 7.8 mg/L (= 84 % oxygen saturation value), and thus, sufficiently high throughout the test period (Table 5). The water temperature varied between 19.2 and 20.1 °C and was thus sufficiently constant. The water temperature differed by less than 1.0 °C between all beakers at any time during the study (Table 6). The measured values for total hardness and ammonium in water samples from the controls and the highest test concentration are given in Table 7.
-Appearance of the test media:
No anomalies or significant differences between the water-sediment systems of the control and treatments were observed during the study period. Starting from Day 7, a typical slight turbidity and biofilm on the walls of test vessels was recorded in all test media. Furthermore, on Day 28, slight algal growth was observed in all test media.

VALIDITY OF THE TEST
The test is considered to be valid since the following criteria are met.
- The emergence of adult midges in the control was 99 % at the end of the test, and therefore higher than the 70 % required by the guidelines (Table 1).
- The emergence of adult midges in the control occurred between Days 13 and 23 after the insertion of the larvae into the test vessels, i.e. in the requested time frame between 12 and 23 days (Table 1). One single female midge emerged on Day 24 in the control (replicate 1). This single midge is not seen to have an overall significant impact on the outcome of the study itself and can still be counted as biological variance within a living test system setup.
- The dissolved oxygen concentrations in the test media were at least 7.8 mg/L (= 84 % oxygen saturation value) throughout the test period, fulfilling the criterion of at least 60 % of air saturation value (ASV) at the end of the test (Table 5).
- At the end of the test, the pH values in the water columns of all test vessels were between pH 7.7 and 8.4, i.e. in the requested range of 6 to 9 (Table 4).
- The water temperature in the test vessels varied between 19.2 and 20.1 °C during the incubation time and was thus sufficiently constant. The water temperature differed by less than 1.0 °C between all vessels at any time during the study (Table 6).

Reported statistics and error estimates:

The mean emergence ratios and development rates of all test concentrations were statistically evaluated on significant differences to the control by Williams t-test, Dunnett t-test or Step- down Cochran-Armitage test after a one-way analysis of variance (ANOVA). Statistical evaluations were done separately for emerged males and females (development rate) and with pooled sexes (emergence ratio).

Table 1: Part of test item transferred to the three compartments

Sampling Day	Nominal Concentration of Active Ingredient in Dry Sediment [mg/kg]	Total Determined Active Ingredient   [%]	Portion of Total Determined in Test Water   [%]	Portion of Total Determined in Pore Water   [%]	Portion of Total Determined in Sediment   [%]
0	62.5 1000	25 36	51 61	23 15	26 24
7	62.5 1000	n.a. 13	n.a. 82	n.a. 6	n.a. 11
28	62.5 1000	n.a 0.2	n.a n.a.	n.a. 0.2	n.a. n.a.

n.a.: not applicable, because the concentration in the sample was < LOQ (LOQ water and pore water = 2.7 mg a.i./L LOQ sediment = 7.5 mg a.i./kg)

 Table 2: Emergence ratio (male and female midges pooled)

 

	Nominal Active Ingredient (Test Item) Concentration [mg/kg dry sediment]
	Control	62.5 (138)	125 (276)	250 (552)	500 (1104)	1000 (2208)
Sum of inserted larvae per treatment	80	80	80	80	80	80
Sum of emerged midges per treatment	79	78	75	77	77	77
% of emerged midges per treatment (mean)	99	98	94	96	96	96
Emergence ratio ERarc: mean	1.51	1.49	1.39	1.43	1.43	1.43
SD	0.113	0.161	0.210	0.163	0.163	0.113
min	1.35	1.25	1.17	1.25	1.25	1.35
max	1.57	1.57	1.57	1.57	1.57	1.57
n	4	4	4	4	4	4
% of control	-	99	92	95	95	93
STAT	-	n.s.	n.s.	n.s.	n.s.	n.s.

       ERarc: Arcsin-transformed emergence ratio

SD: Standard deviation

n:  Number of replicates

STAT: Results of a Dunnett’s Multiple t-test (a= 0.05, one-sided smaller)

n.s.:   Mean ERarc not statistically significantly lower than in thecontrol

 

 Table 3: Development rate for males and females

Males
Nominal Active Ingredient (Test Item) Concentration [mg/kg drysediment]	Control	62.5 (138)	125 (276)	250 (552)	500 (1104)	1000 (2208)
Development Rate per Treatment[day^-1]
Mean	0.0687	0.0674	0.0710	0.0731	0.0714	0.0703
SD	0.00570	0.00356	0.00171	0.00260	0.00125	0.00247
min	0.0604	0.0642	0.0691	0.0712	0.0703	0.0682
max	0.0733	0.0714	0.0732	0.0769	0.0730	0.0737
n	4	4	4	4	4	4
% of Control	-	98	103	106	104	102
STAT	-	n.s.	n.s.	n.s.	n.s.	n.s.

        SD:Standard deviation

n: Number ofreplicates

STAT: Results of aDunnett’s Multiple t-test(a= 0.05, one-sided smaller)

n.s.:   Mean developmental rate not statistically significantly lower than in thecontrol

 

Females
Nominal Active Ingredient (Test Item) Concentration [mg/kg drysediment]	Control	62.5 (138)	125 (276)	250 (552)	500 (1104)	1000 (2208)
Development Rate per Treatment[day^-1]
Mean	0.0642	0.0674	0.0659	0.0645	0.0668	0.0694
SD	0.00389	0.00065	0.00194	0.00310	0.00190	0.00415
min	0.0595	0.0667	0.0634	0.0606	0.0656	0.0658
max	0.0677	0.0683	0.0680	0.0673	0.0696	0.0743
n	4	4	4	4	4	4
% of Control	---	104	102	100	103	107
STAT	---	n.s.	n.s.	n.s.	n.s.	n.s.

        SD:        Standard deviation

n:         Number ofreplicates

STAT: Results of a Welch t-test after Bonferroni–Holm (a= 0.05, one-sided smaller)

n.s.:Mean developmental rate not statistically significantly lower than in thecontrol

Table 4: pH values in the test media

Exposure Time [Days]	pH Values
	Nominal Active Ingredient (Test Item) Concentration [mg/kg dry sediment]
	Control	62.5 (138)			125 (276)	250 (552)		500 (1104)	1000 (2208)
0	7.7	7.7			7.7	7.7		7.7	7.7
7	8.0 - 8.1	8.0	-	8.1	8.1	8.0	- 8.1	8.0 - 8.1	8.0
14	8.2 - 8.3	8.2	-	8.3	8.2 - 8.3	8.3		8.2 - 8.3	8.2
21	8.3	8.3	-	8.4	8.3	8.3		8.2 - 8.3	8.2 - 8.3
28	8.3 - 8.4	8.3	-	8.4	8.3 - 8.4	8.3		8.4	8.3 - 8.4

 

Table 5: Dissolved oxygen concentrations in the test media

Exposure Time [Days]	Dissolved Oxygen Concentrations [mg/L]
	Nominal Active Ingredient (Test Item) Concentration [mg/kg dry sediment]
	Control	62.5 (138)			125 (276)			250 (552)			500 (1104)			1000 (2208)
0	8.0 - 8.5	8.4	-	8.6	8.2	-	8.4	8.3	-	8.4	8.5	-	8.6	8.3	-	8.5
7	8.5 - 8.7	8.6	-	8.7	8.6	-	8.7	8.6			8.5	-	8.6	8.5	-	9.6
14	8.3 - 8.4	8.5	-	8.6	8.4	-	8.6	8.4	-	8.6	8.5	-	8.6	8.5	-	8.6
21	8.4 - 8.8	8.7	-	8.9	8.7	-	8.8	8.8	-	8.9	8.7	-	8.8	8.4	-	8.8
28	8.3 - 8.4	7.8	-	8.4	7.8	-	8.2	8.2	-	8.4	8.4			8.2	-	8.5

 

 Table 6: Water temperature in the test media

Exposure Time [Days]	Water Temperature [°C]
	Nominal Active Ingredient (Test Item) Concentration [mg/kg dry sediment]
	Control	62.5 (138)			125 (276)			250 (552)			500 (1104)			1000 (2208)
0	19.6 - 19.8	19.6	-	19.8	19.5	-	19.9	19.6	-	19.8	19.6	-	19.8	19.7	-	19.8
7	19.5 - 20.1	19.6	-	19.8	19.4	-	19.9	19.5	-	19.8	19.7	-	19.9	19.6	-	19.9
14	19.8 - 19.9	19.8			19.8	-	19.9	19.7	-	19.8	19.6	-	19.7	19.6	-	19.7
21	19.4	19.2	-	19.3	19.2	-	19.3	19.2	-	19.3	19.2	-	19.3	19.2	-	19.3
28	19.3 - 19.4	19.3	-	19.4	19.3			19.2	-	19.3	19.2	-	19.4	19.3

Table 7: Total water hardness and ammonium concentration in the test media

Treatment	NH4-N [mg/L]		Total Water Hardness [mg/L as CaCO3]
	Day 0	Day 28	Day 0	Day 28
Control	0.605	45.1	230	340
1000 mg a.i./kg dry sediment	0.458	48.1	230	350

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the test item Propionaldehyde, reaction product with formaldehyde (EC No 701-281-9) had no toxic effects on the emergence ratio and the development of sediment-dwelling larvae of the midge Chironomus riparius in water-sediment systems after 28 days up to the highest tested mean measured concentration of 31.5 mg a.i./kg dry sediment (corresponding to 69.6 mg test item /kg dry sediment). Consequently, the 28-day NOEC was determined to be ≥31.5 mg a.i./kg dry sediment (corresponding to 69.6 mg test item /kg dry sediment). The 28-day LOEC was >31.5 mg a.i./kg dry sediment (corresponding to 69.6 mg test item /kg dry sediment).

Executive summary:

 A sediment toxicity test was performed according to OECD 218.A range finding test with the following nominal test concentrations was conducted: 1.0, 10 and 100 mg a.i./kg dry sediment corresponding to 2.21, 22.1 and 221 mg test item/kg dry sediment. Additionally, a control was run in parallel. For all treatments two replicates with 20 test organisms each were prepared. The chironomids were exposed to the test item for 28 days. No toxic effects were observed at 100 mg a.i./kg dry sediment in the range finding test. The results of the range finding test were confirmed by the main test.The analytically measured concentrations of Propionaldehyde, reaction product with formaldehyde in the application solution samples ranged from 90 to 106 % of the nominal values. This confirmed the correct preparation of the application solutions.

The total recovery of the nominal amounts of applied test item found in the sediment immediately after application (Day-2) ranged from 81 % to 93 % in all tested concentrations. Thus, the correct application of the test item could be verified.

For the quantification of the test item concentrations in the three compartments water, pore water and sediment, the concentration of the active ingredient was analytically determined in the lowest and highest tested concentration (62.5 and 1000 mg a.i./kg dry sediment). During the equilibration (Day -2 to 0) and the test period (Day 0 to 28), the test item concentration in the three compartments rapidly decreased. The total recovery of the nominal amounts of applied test item found in the three compartments ranged from 25 to 36 % at test start (Day 0). After 7 and 28 days of the exposure no test item were determined in the concentration of 62.5 mg a.i./kg. In the concentration of 1000 mg a.i./kg, 13 and 0.2 % of the total nominal amount were determined after 7 and 28 days, respectively. The mean measured concentration of the highest nominal active ingredient concentration of 1000 mg a.i./kg dry sediment (corresponding to 2208mg test item/kg dry sediment) was calculated as time-weighted mean over measurements on Day 0, 7 and 28. The highest tested mean measured concentration corresponds to 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment.The biological test results were based on the mean measured concentration of the active ingredient and the test item in the dry sediment, since the test item decreased during the test. The emergence ratio per vessel in the control was 99 % (thus fulfilling the guideline validity criterion of≥70 %). The test item had no statistically significant inhibitory effect on the emergence ratios of pooled sexes during the test period of 28 days up to and including the highest mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment (results of Dunnett’s t-test, a = 0.05, one-sided greater).The emergence of adult midges in the control occurred between Days 13 and 23 after the insertion of the larvae into the test vessels, i.e. in the requested time frame between 12 and 23 days. One single female midge emerged on Day 24 in the control (replicate 1). This single midge is notseen to have an overall significant impact on the outcome of the study itself and can still be counted as biological variance within a living test system setup. The mean development rates of males and fimaled were not statistically significantly lower than in the control up to and including the highest mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment, according to a Dunnett’s and Welch t-test after Bonferroni –Holm t-test (a= 0.05, one-sided smaller), respectively. No symptoms of toxicity were observed at the larvae, pupae and emerged midges during the study.

 

The test is considered to be valid since the following criteria are met.

- The emergence of adult midges in the control was 99 % at the end of the test, and therefore

higher than the 70 % required by the guidelines.

- The emergence of adult midges in the control occurred between Days 13 and 23 after the insertion of the larvae into the test vessels, i.e. in the requested time frame between 12 and 23 days. One single female midge emerged on Day 24 in the control (replicate 1). This single midge is not seen to have an overall significant impact on the outcome of the study itself and can still be counted as biological variance within a living test system setup.

- The dissolved oxygen concentrations in the test media were at least 7.8 mg/L (= 84 % oxygen saturation value) throughout the test period, fulfilling the criterion of at least 60 % of air saturation value (ASV) at the end of the test.

- At the end of the test, the pH values in the water columns of all test vessels were between pH 7.7 and 8.4, i.e. in the requested range of 6 to 9.

- The water temperature in the test vessels varied between 19.2 and 20.1 °C during the incubation time and was thus sufficiently constant. The water temperature differed by less than 1.0 °C between all vessels at any time during the study.

The 28-day EC15 and EC50 values could not be calculated due to the absence of toxicity of the test item.

Taking into account the emergence ratios and development rates ofChironomus ripariusand observations of any toxicity symptoms, the overall 28-day NOEC of Propionaldehyde, reaction product with formaldehyde in this water-sediment study was equal to or higher than the highest tested mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment.

The 28-day LOEC was higher than the mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment.

Description of key information

A sediment toxicity test was performed according to OECD 218. The 28-day NOEC was determined to be ≥31.5 mg a.i./kg dry sediment (corresponding to 69.6 mg test item /kg dry sediment). The 28-day LOEC was >31.5 mg a.i./kg dry sediment (corresponding to 69.6 mg test item /kg dry sediment).

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater sediment:

31.5 mg/kg sediment dw

Additional information

 A sediment toxicity test was performed according to OECD 218.A range finding test with the following nominal test concentrations was conducted: 1.0, 10 and 100 mg a.i./kg dry sediment corresponding to 2.21, 22.1 and 221 mg test item/kg dry sediment. Additionally, a control was run in parallel. For all treatments two replicates with 20 test organisms each were prepared. The chironomids were exposed to the test item for 28 days. No toxic effects were observed at 100 mg a.i./kg dry sediment in the range finding test. The results of the range finding test were confirmed by the main test.The analytically measured concentrations of Propionaldehyde, reaction product with formaldehyde in the application solution samples ranged from 90 to 106 % of the nominal values. This confirmed the correct preparation of the application solutions.

The total recovery of the nominal amounts of applied test item found in the sediment immediately after application (Day-2) ranged from 81 % to 93 % in all tested concentrations. Thus, the correct application of the test item could be verified.

For the quantification of the test item concentrations in the three compartments water, pore water and sediment, the concentration of the active ingredient was analytically determined in the lowest and highest tested concentration (62.5 and 1000 mg a.i./kg dry sediment). During the equilibration (Day -2 to 0) and the test period (Day 0 to 28), the test item concentration in the three compartments rapidly decreased. The total recovery of the nominal amounts of applied test item found in the three compartments ranged from 25 to 36 % at test start (Day 0). After 7 and 28 days of the exposure no test item were determined in the concentration of 62.5 mg a.i./kg. In the concentration of 1000 mg a.i./kg, 13 and 0.2 % of the total nominal amount were determined after 7 and 28 days, respectively. The mean measured concentration of the highest nominal active ingredient concentration of 1000 mg a.i./kg dry sediment (corresponding to 2208mg test item/kg dry sediment) was calculated as time-weighted mean over measurements on Day 0, 7 and 28. The highest tested mean measured concentration corresponds to 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment.The biological test results were based on the mean measured concentration of the active ingredient and the test item in the dry sediment, since the test item decreased during the test. The emergence ratio per vessel in the control was 99 % (thus fulfilling the guideline validity criterion of≥70 %). The test item had no statistically significant inhibitory effect on the emergence ratios of pooled sexes during the test period of 28 days up to and including the highest mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment (results of Dunnett’s t-test, a = 0.05, one-sided greater).The emergence of adult midges in the control occurred between Days 13 and 23 after the insertion of the larvae into the test vessels, i.e. in the requested time frame between 12 and 23 days. One single female midge emerged on Day 24 in the control (replicate 1). This single midge is notseen to have an overall significant impact on the outcome of the study itself and can still be counted as biological variance within a living test system setup. The mean development rates of males and fimaled were not statistically significantly lower than in the control up to and including the highest mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment, according to a Dunnett’s and Welch t-test after Bonferroni –Holm t-test (a= 0.05, one-sided smaller), respectively. No symptoms of toxicity were observed at the larvae, pupae and emerged midges during the study.

 

The test is considered to be valid since the following criteria are met.

- The emergence of adult midges in the control was 99 % at the end of the test, and therefore

higher than the 70 % required by the guidelines.

- The emergence of adult midges in the control occurred between Days 13 and 23 after the insertion of the larvae into the test vessels, i.e. in the requested time frame between 12 and 23 days. One single female midge emerged on Day 24 in the control (replicate 1). This single midge is not seen to have an overall significant impact on the outcome of the study itself and can still be counted as biological variance within a living test system setup.

- The dissolved oxygen concentrations in the test media were at least 7.8 mg/L (= 84 % oxygen saturation value) throughout the test period, fulfilling the criterion of at least 60 % of air saturation value (ASV) at the end of the test.

- At the end of the test, the pH values in the water columns of all test vessels were between pH 7.7 and 8.4, i.e. in the requested range of 6 to 9.

- The water temperature in the test vessels varied between 19.2 and 20.1 °C during the incubation time and was thus sufficiently constant. The water temperature differed by less than 1.0 °C between all vessels at any time during the study.

The 28-day EC15 and EC50 values could not be calculated due to the absence of toxicity of the test item.

Taking into account the emergence ratios and development rates ofChironomus ripariusand observations of any toxicity symptoms, the overall 28-day NOEC of Propionaldehyde, reaction product with formaldehyde in this water-sediment study was equal to or higher than the highest tested mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment.

The 28-day LOEC was higher than the mean measured concentration of 31.5 mg a.i./kg dry sediment corresponding to 69.6 mg test item /kg dry sediment.