Bis(piperidinothiocarbonyl) hexasulphide

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:

03-22-2017 to 04-12-2017

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:

yes

Remarks:

The temperature for the study was slightly higher than stated in the guideline. As no immobility in the blank control occurred during the test and all validity criteria were fulfilled, this deviation was stated as uncritical.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Remarks:

Due to the test items properties, the study was performed without analytical determination of the test item.

Vehicle:

yes

Remarks:

Because of the very low solubility of the test item, acetone was used to spike the test solutions.

Details on test solutions:

During validation of the analytical method in spiked solutions at the concentration of 10 µg/L (taken as limit of water solubility) in test medium, no test item was detectable. That means solubility in test medium is much lower than in demineralised water. Development of an analytical method for measurement of test item in test medium was not possible.
Because test item is not measurable, in agreement with the OECD guidance document no. 23, no analytical determination of the test item in the test solutions was made in this study and the effects were based on nominal concentrations.

The solubility in water is stated as 10.48 µg/L (MSDS, provided by the sponsor). In this study, the limit of water solubility was used as highest concentrated treatment. Because of the very low solubility of the test item, acetone was used to spike the test solutions. Stock solutions containing 105 mg/L nominal concentration (real load 105 – 115 mg/L) and 5 mg/L of test item (prepared from the 105 mg/L stock solution) were prepared in acetone.

Test organisms (species):

Daphnia magna

Details on test organisms:

Species Daphnia magna
Variety STRAUS
Arrival of Strain 27. Sep. 2007
Sex female
Age between 0 and 24 hours
The animals which were used in the test did not belong to the first brood of the respective parent animals.

ANIMAL HUSBANDRY
Daphnia magna is bred in the LAUS GmbH throughout the year. The animals were originally obtained from the Umweltbundesamt in Berlin and are kept for the use in toxicity tests. They multiply by parthenogenesis, thus being genetically identical. The husbandry is performed similar to the method described in the OECD guideline, following SOP 115 002 01 (“Zucht und Hälterung von Daphnia magna STRAUS“), edition 12, adopted 02. Feb. 2015.
Vessels glass beakers, nominal volume 2 L
Medium M4-Medium (recipe of ELENDT)
Food green alga (Desmodesmus subspicatus)
Medium renewal twice a week
Photo period 1 6/8 hours, using neon tubes
Temperature 20 +/-2 °C

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

21 d

Hardness:

267 - 356 mg CaCO3/L

Test temperature:

19.4 – 22.4°C

pH:

7.7 - 8.0

Dissolved oxygen:

8.5 - 9.5

Salinity:

Freshwater

Nominal and measured concentrations:

Nominal concentrations: 0 - 5 - 10.5 µg/L

Details on test conditions:

Duration 21 days
Loading 80 mL/animal, animals were kept individually
Replicates 10 replicates/treatment
Treatments 10.5 and 5 µg/L
Blank Control dilution water
Solvent Control 100 µL acetone / L dilution water
Lighting 1000 Lux
Aeration none
Feeding unicellular green algae Desmodesmus subspicatus: 0.15 - 0.20 mg organic carbon/animal/day, the amount of carbon is based on photo metric measurement (linear cor-relation between absorption at 440 nm and measured DOC concentration).

Reference substance (positive control):

no

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 10.5 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: No effect up to solubility limit

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

> 10.5 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Details on results:

Calculation of results was performed with the help of validated software (Microsoft Excel®). The estimation of the biological results was accomplished using the software Tox-Rat® Professional, version 3.2.1. The number of offspring in the solvent control was slightly higher than in the blank control but the difference between the control and the solvent control was not significant. Therefore, in agreement with the OECD guideline, for statistical evaluation, all blank control and solvent control replicates were pooled.

Table 1: Offspring

Replicate No.	Blank Control	Solvent Control	5 µg/L	10.5 µg/L
1	105	112	120	86
2	112	125	90	106
3	109	M	M	113
4	119	112	118	M
5	114	101	119	93
6	104	112	100	111
7	95	121	104	72
8	66	107	90	M
9	97	98	102	72
10	86	90	99	112
Mean	101	109	105	96
SD	16	11	12	17
RSD	16	10	11	18

SD = standard deviation;

RSD = relative standard deviation = coefficient of variation

M = mortality of parent animal

Table 2:     Fecundity

Treatment	Total Offspring	Surviving Parent Animals	Mean Offspring per Surviving Parent Animal
Blank Control	1007	10	101
Solvent Control	978	9	109
5 µg/L	942	9	105
10.5 µg/L	765	8	96

Validity criteria fulfilled:

yes

Conclusions:

One valid experiment was performed according to OECD 211 Guideline in order to evaluate the effect of test item on the reproduction of Daphnia magna.

RESULTS:
Based on nominal concentrations,
NOEC = 10.5 µg/L
LOEC > 10.5 µg/L

VALIDITY CRITERIA:
All validity criteria were met.

PARAMETER DEMANDED VALUE FOUND VALUE
Mortality of parent animals in the blank control < 20 % 0 %
Mean surviving offspring in the blank control > 60 101
Mortality of parent animals in the solvent con-trol < 20 % 10 %
Mean surviving offspring in the solvent control > 60 109
O2 concentration > 3 mg/L = 8.5 mg/L
pH range 6 – 9 7.7 - 8.0
pH variation < 1.5°C 0.3°C
Temperature 18°C - 22°C, 19.4°C – 22.4°C
variation = 2.0 units variation of 3.0 units

The temperature and the range of the temperature was slightly higher than stated in the study plan (22.4 °C instead of 22.0°C, difference 3 °C instead of = 2.0 °C) . Because no mortality above the validity criteria and no abnormal behaviour was observed in the controls, this can be stated as uncritical.

Executive summary:

One valid experiment was performed according to OECD 211 Guideline in order to evaluate the effect of test item on the reproduction of Daphnia magna.

The solubility in water was considered as 10.48 µg/L (see OECD 105 study included in the present REACh dossier). In this study, the limit of water solubility was used as highest concentrated treatment. The study was performed using the concentrations 10.5 µg/L and 5 µg/L. Because of the very low solubility of the test item, acetone was used to spike the test solutions. Therefore a solvent control was prepared in addition to the blank control (solvent concentration: 0.1 mL/L).

For each control and test item treatment, ten daphnia were exposed for 21 days.

Medium renewal was performed every day to maximize exposure of the test organism to the test item. The offspring of the animals was counted every day.

Significant decrease in the reproduction of the daphnia was not observed in the treatments.

During validation of the analytical method in spiked solutions at the concentration of 10 µg/L (taken as limit of water solubility) in test medium, no test item was detectable. That means solubility in test medium is much lower than in demineralised water. Development of an analytical method for measurement of test item in test medium was not possible.

Because test item is not measurable, in agreement with the OECD guidance document no. 23, no analytical determination of the test item in the test solutions was made in this study and the effects were based on nominal concentrations.

 

The following results were determined for the test item:

NOEC >=10.5 µg/L
LOEC > 10.5 µg/L

Additional information

One valid experiment was performed according to OECD 211 Guidelinein order to evaluate the effect of test item on the reproduction ofDaphnia magna.

The solubility in water was stated as 10.48 µg/L. In this study, the limit of water solubility was used as highest concentrated treatment. The study was performed using the concentrations 10.5 µg/L and 5 µg/L. Because of the very low solubility of the test item, acetone was used to spike the test solutions. Therefore a solvent control was prepared in addition to the blank control (solvent concentration: 0.1 mL/L). For each control and test item treatment, ten daphnia were exposed for 21 days. Medium renewal was performed every day to maximize exposure of the test organism to the test item. The offspring of the animals was counted every day.

Significant decrease in the reproduction of the daphnia was not observed in the treatments. It is concluded that no adversed effect was detected up to the water solubility limit of DPTH.