Reaction mass of decamethyltetrasiloxane; dodecamethylpentasiloxane; hexamethyldisiloxane; octamethyltrisiloxane

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-10-14 to 1991-10-24

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Guideline study; GLP. Most test concentrations tested were above the limit of water solubility for this compound.  Measured concentrations were significantly lower than nominal concentrations, reflecting the low water solubility of the compound.

Qualifier:

according to guideline

Guideline:

EPA OTS 797.1400 (Fish Acute Toxicity Test)

Qualifier:

according to guideline

Guideline:

other: EEC Directive 79/831

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Sampling: Analytical determination of concentration was performed at the beginning of the test in the stock solutions and the test media at the beginning and end of the test. Water samples were taken from a point approximately midway between the surface, bottom and sides of each aquarium by means of glass pipettes of 20 mL volume carefully dipped into the solution. The samples were filled into volumetric flasks of 20 mL nominal volume. 0.5 mL n-decane containing the toluene used as internal standard for gas chromatography is added. The flask is closed and then shaken for about one minute. The above operations were performed immediately to minimize the losses of the test substance (M2) due to evaporation and reactions at the water interface. From the n-decane phase on top of the water phase, approximately 0.3 mL was taken by a suitable syringe and filled into a 1 mL vial. The vials were stored in a refrigerator until analysis. The procedure for sampling and preparing the stock solution samples were very similar to those used for the test solutions.
water.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)

- Method: Seven stock solutions were prepared using iso-propanol as a co-solvent. These stock solutions were dosed into the water inlet of the aquaria under the test medium level. The stock solutions were continuously agitated during the test by magnetic stirrers and were dosed at intervals of 36 sec into the water flowing into the respective aquarium by HAMILTON dispensers controlled by a computer. The volume per dosing cycle was 10 μL.

Test water continuously flowed into the aquaria via an inlet tube at a rate of 10 L/h regulated by a flow-meter. The aquaria were made of glass and had a size of 32 x 36 x 38 cm (L x D x H). The test volumes amounted to 40 L. Thus, the test volume was exchanged 6 times per day. In all the aquaria with the exception of the control, the iso-propanol concentration was 0.1 ml/L. The control aquarium contained only test water. Stock solutions were weighed prior to the start of the dosing system and at test termination to determine the total consumption of stock solution per aquarium.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM

- Length at study initiation (length definition, mean, range and SD): 5.4 +/- 0.4 cm

- Weight at study initiation (mean and range, SD): 1.5 +/- 0.4 g

- Culture conditions: Fish were held and tested under a 16/8 light/dark cycle.

- Observations: Fish were monitored daily for mortality and symptoms of intoxication.

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

40 - 60 mg/L as CaCO3

Test temperature:

12+/-1°C

pH:

7.4 - 7.6

Dissolved oxygen:

10.8 - 11.7 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0 (Control), 0 (Solvent control; iso-propanol), 0.16, 0.28, 0.50, 0.89, 1.58, 2.81, and 5.00 mg/L.

Analytical results confirm that stock solutions were 80-90% of nominal values and the test substance was stable for the duration of the test. Measured concentrations ranged from 13-56% of nominal concentrations. The lower percentages were at the higher test concentrations, at or above the limit of water solubility (~0.93 mg/L).

Details on test conditions:

TEST SYSTEM

- Test vessels: The aquaria were made of glass and had a size of 32 x 36 x 38 cm (L x D x H). The test volumes amounted to 40 L. About 4 hours before the start of the test the aquaria were filled with the respective test medium by starting the water flow and the dosing system.
Immediately before the start of the test.

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 1

- No. of vessels per vehicle control (replicates): 1

TEST MEDIUM / WATER PARAMETERS

- Culture medium different from test medium: No. Reconstituted water prepared by adding salt stock solutions to demineralized
water (conductivity < 0.2 μmho/cm).

- Intervals of water quality measurement: Dissolved oxygen and pH were also measured daily.  Water temperature was monitored and recorded hourly in the control aquaria.

Reference substance (positive control):

not specified

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.46 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: calculated independently of report author

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3.02 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL 1.58-5.00

Details on results:

- Mortality of control: No mortalities or symptoms of intoxication occurred in the control or solvent control groups.

- Effect concentrations exceeding solubility of substance in test medium: Most test concentrations tested were above the limit of water solubility for this compound.  Measured concentrations were significantly lower than nominal concentrations, reflecting the low water solubility of the compound.

Reported statistics and error estimates:

The LC50 value was calculated by the binomial probability method.

Sublethal observations / clinical signs:

Table 1. Results of analysis of test media

 

Nominal concentration (mg/L)	Day 0 measured concentration (mg/L)	Day 4 measured concentration (mg/L)	Mean measured concentration (mg/L)
0 (Control)	-	-	-
0 (Solvent control)	-	-	-
0.16	0.08	0.09	0.09
0.28	0.10	0.12	0.11
0.50	0.07	0.28	0.18
0.89	0.26	0.21	0.24
1.58	0.37	0.37	0.37
2.81	0.32	0.56	0.44
5.00	0.43	0.74	0.59

 

 Table 2. Test results – percentage mortalities throughout the test

 

Nominal concentration (mg/L)	4 hours	24 hours	48 hours	72 hours	96 hours
0 (Control)	0	0	0	0	0
0 (Solvent control)	0	0	0	0	0
0.16	0	0	0	0	0
0.28	0	0	0	0	0
0.50	0	0	0	0	0
0.89	0	0	0	0	0
1.58	0	0	0	0	0
2.81	0	0	10	20	40
5.00	0	0	10	70	100

 

Validity criteria fulfilled:

yes

Conclusions:

A 96-hr LC50 value of 3.02 mg/L has been determined for the effects of the test substance on mortality of Oncorhynchus mykiss based on nominal concentrations. A 96-hr LC50 value of 0.46 mg/L ahas been re-calculated based on mean measured concentrations.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007-08-22 to 2007-11-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Water samples were taken from each test chamber prior to test initiation (pre-test), at test initiation and at test termination. Water samples (10 mL) were collected using a 10 mL volumetric pipette and placed in a 20-mL glass scintillation vial .

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: The nominal test concentrations were selected on the basis of the reported solubility of the substance (34 μg/L). A primary stock was prepared by isotropic dilution of the 14C-labeled L3 with non-radiolabeled L3. A 7.0 μL aliquot of 14C-L3 (0.00583 g) was added to a 1.0 mL vial. A 200 μL aliquot (0.16344 g) of L3 was also added to the vial. Approximately 0.5 mL of dimethyl formamide (DMF) was added to the vial and the contents of the vial was transferred to a 500-mL volumetric flask. The flask was then brought to volume with DMF, and mixed well. Three 0.1 mL aliquots of the primary stock were counted by LSC. The specific activity of the primary stock was determined to be 6.743 μCi/mg.

Four additional stock solutions were prepared at concentrations of 170, 85, 43 and 21 mg/L by proportional dilution of the primary stock with DMF. DMF only was used as the solvent control. The stock solutions were delivered to the diluter mixing chambers (at a rate of 0.0150 mL/minute) where they were diluted with dilution water (at a rate of 150 mL/min) to achieve the desired test concentrations. Test vessels and mixing chambers remained clear and colourless throughout the test. The concentration of DMF in the solvent control and the treated media was 0.1 mL/L.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM

- Common name: Rainbow trout

- Source: Thomas Fish Company, Anderson, CA., USA

- Length at study initiation (length definition, mean, range and SD): 45 (40-49) mm

- Weight at study initiation (mean and range, SD): 0.73 (0.50-0.88) g

- Feeding during test: None


ACCLIMATION

- Acclimation period: 7 days

- Acclimation conditions: Same as test

- Type and amount of food: Finfish starter #1, Zeigler brothers, Gardners, PA., USA

- Health during acclimation (any mortality observed): No mortality

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

137 mg/L as CaCO3

Test temperature:

11.5-12.3°

pH:

7.3-7.5

Dissolved oxygen:

≥8.6 mg/L (≥82% ASV)

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0 (Control), 0 (Solvent control), 2.1, 4.3, 8.5, 17 and 34 μg/L

Mean measured concentrations:
The measured concentrations in the treated media corresponded to 57, 49, 55, 52 and 56% of the nominal values respectively.

The results are reported with reference to the mean measured concentrations.

Details on test conditions:

- Exposure vessel type:  25-L polyethylene aquaria containing 15-L of test solution and covered with clear plexiglass lids.

- Delivery of test media: Syringe pumps were used to deliver working stock solutions and solvent to the mixing chambers where they were mixed with dilution water. Dilution water was delivered to the chambers using calibrated rotameters. After mixing the test solutions were split into two replicate test chambers. The test substance is relatively volatile (4 mm at 25°C) and flow rates were adjusted to achieve approximately 7.2 volume additions per day with the aim of maximising exposures. The diluter system was operated for approximately 8 hours before the start of the fish exposures to allow stabilisation.

- Number of replicates, fish per replicate:  Two replicates per treatment, 10 Fish per replicate

- Dilution water source:  Dechlorinated Municipal Water from Bay City, Michigan

- Dilution water chemistry:  Hardness 137 mg/L as CaCO3, Alkalinity 45 mg/L as CaCO3, Conductivity 392  μmhos/cm        

- Vehicle/solvent and concentrations:  The solvent control and treatment groups contained 0.1 mL/L DMF

- Water chemistry in test:  DO, pH and temperature measured in each test chamber daily

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 19 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: none

- Mortality of control: none

Reported statistics and error estimates:

No significant effects on mortality were recorded in the highest treatment. An LC50 value could therefore not be determined.

Sublethal observations / clinical signs:

Table 1. Test results

Nominal concentration (μg/L)	Mean measured concentration (μg/L)	Mean percentage mortality after 96 hours
0 (Control)	<LoQ	0
0 (Vehicle control)	<LoQ	0
2.1	1.2	0
4.3	2.1	0
8.5	4.7	0
17	8.9	0
34	19	0

Validity criteria fulfilled:

yes

Conclusions:

A 96-hour LC50 value of >19 μg/L has been determined for the effects of the substance on mortality of Oncorhynchus mykiss based on mean measured concentrations. The results were obtained under flow-through test conditions.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008-04-29 to 2008-05-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Sampling: Measurement of test concentrations in one replicate test chamber of each treatment group at test initiation and then on days 1, 2 and 3 and at test termination. water samples were collected from each test vessel at mid-depth of the solutions. Water samples (10 mL) were collected using a 10 ml volumetric pipette and placed in a 20 ml glass scintillation vial.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: The nominal test concentrations were selected on the basis of the reported solubility of the substance (6.7 μg/l). A primary stock was prepared by isotropic dilution of the 14C-labeled L4 with non-radiolabeled L4. Approximately 2 ml of dimethyl formamide (DMF) was transferred to a 10-ml conical vial with a septum cap. A 7.0 μl aliquot of C14-L4 (0.00660 g) and a 37 μl aliquot of L4 (0.03167 g) was added to the vial through the septum cap. The total weight of 14C-L4 and L4 was 0.03827 g. The contents of the vial were transferred to a 500-ml volumetric flask, brought to volume with DMF, and mixed well. Three 0.05 ml aliquots of the primary stock were added to 10 ml of scintillation cocktail and counted by LSC. The specific activity of the primary stock was determined to be 48.6 μCi/mg.

Four additional stock solutions were prepared at concentrations of 38, 19, 9.6 and 4.8 mg/l by serial dilution of the primary stock with DMF. DMF only was used as the solvent control. The stock solutions were delivered to the diluter mixing chambers (at a rate of 0.015 ml/minute) where they were diluted with dilution water (at a rate of 150 ml/min) to achieve the desired test concentrations. Test vessels and mixing chambers remained clear and colourless throughout the test.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM

- Test fish:  Total Length 5.4 cm (Range 4.8 to 6.2 cm)/Wet Weight 1.21 g (Range 0.796 to 1.77 g).

- Date of supply: 2008-03-25

- Pre-experiment holding period: 37 days

- Holding conditions: Similar to test conditions

- Pre-test mortalities: none

- Test loading: 0.112 g/l over 24 hours (flow through), 0.808 g/l (instantaneous).

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

Hardness 139 mg/l as CaCO3, Alkalinity 62 mg/l as CaCO3

Test temperature:

11.4 - 12.3ºC

pH:

7.1-7.6

Dissolved oxygen:

≥7.8 mg/l

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: Negative Control, Solvent Control, 0.42, 0.84, 1.7, 3.4 and 6.7 μg/l

Mean measured concentrations in treatments: 0.33, 0.65, 1.4, 3.4 and 6.3 μg/l.

Mean measured concentrations in treatments as a percentage of nominal: 79, 77, 84, 101 and 94%

The results are interpreted with reference to mean measured concentrations.

Details on test conditions:

- Exposure vessel type:  25-litre polyethylene aquaria containing 15-litres of test solution and covered with clear plexiglass lids

- Number of replicates, fish per replicate:  Two replicates per treatment, 10 Fish per replicate

- Dilution water source:  Dechlorinated Municipal Water

- Dilution water chemistry:  Hardness 139 mg/l as CaCO3, Alkalinity 62 mg/l as CaCO3, Conductivity 336  mhos/cm        

- Vehicle/solvent and concentrations:  The solvent control and treatment groups contained 0.1 ml/l DMF

- Water chemistry in test:  DO, pH and temperature measured in each test chamber daily

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 6.3 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No mortalities or other signs of toxicity were observed in any treatment.

Reported statistics and error estimates:

There was no significant mortality in any treatment; statistical analysis was therefore not required.

Sublethal observations / clinical signs:

Table 1. Test results

Nominal concentration (μg/l)	Mean measured concentration (mg/l)	Percentage mortality after 24 hours	Percentage mortality after 48 hours	Percentage mortality after 72 hours	Percentage mortality after 96 hours
0 (Control)	-	0	0	0	0
0 (Vehicle control)	-	0	0	0	0
0.42	0.33	0	0	0	0
0.84	0.65	0	0	0	0
1.7	1.4	0	0	0	0
3.4	3.4	0	0	0	0
6.7	6.3	0	0	0	0

       

Validity criteria fulfilled:

yes

Conclusions:

A 96-hour LC50 value of >6.3 μg/l has been determined for the effects of the substance on mortality of Oncorhynchus mykiss based on mean measured concentrations.

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008-04-29 to 2008-05-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Sampling: Samples were collected from one test chamber of each treatment and control group four days and two days prior to the start of the test after conditioning the diluter for approximately 45 and 96 hours respectively. Water samples were collected from alternating replicate test chambers in each treatment and control group at the beginning of the test and at 48 and 96 hours (+/-1 hour) to measure concentrations of the test substance. The samples were collected were collected from mid-depth into a 100 ml glass volumetric flask and analysed immediately.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: A primary stock was prepared by mixing a calculated amount of test substance into HPLC-grade dimethyl formamide (DMF) at a nominal concentration of 10 μg/ml. An aliquot of the primary stock solution was diluted with DMF to create a secondary stock solution at a concentration of 700 ng/l. Four additional stock solutions were prepared in DMF at nominal concentrations of 44, 88, 180 and 350 ng/ml. The stock solutions were mixed by inversion and appeared clear and colourless. Stock solutions were stored refrigerated in glass amber bottles or a 500 ml graduated cylinder, and aliquots of each stock were placed in the syringe every two days of the study.

The five test substance stock solutions were injected into the diluter mixing chambers at a rate of 20 μl/minute) where they were mixed with dilution water delivered at a rate of 200 mL/minute to achieve the desired test concentrations. The negative control received dilution water only. The solvent control was prepared by delivering HPLC-grade DMF to the mixing chamber for the solvent control. The DMF concentration in the solvent control and all L5 treatments was 0.1 ml/l.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM

- Test fish:  Total Length 5.0 cm (Range 4.5 to 5.3 cm)/Wet Weight 0.94 g (Range 0.65 to 1.2 g).

- Pre-experiment holding period: 14 days

- Holding conditions: Similar to test conditions

- Feeding during holding: The fish were fed daily with a commercially-prepared diet supplied by Zeigler Brothers Inc., Gardners, PA., USA. The fish were not fed for two days prior to the test or during the test.

- Test loading: 0.065 g/L/day over 24 hours (flow through), 0.63 g/L (instantaneous).

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

Hardness 132 mg/L as CaCO3, Alkalinity 178 mg/L as CaCO3

Test temperature:

12+/-1ºC

pH:

8.0-8.2

Dissolved oxygen:

≥7.2 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: Negative Control, Solvent Control, 4.4, 8.8, 18, 35 and 70 ng/L

Mean measured concentrations in treatments: 2.7, 7.5, 13.2, 35.1 and 75.1 ng/L.

Mean measured concentrations in treatments as a percentage of nominal: 61, 85, 73, 100 and 107%

The results are interpreted with reference to mean measured concentrations.

Details on test conditions:

- Exposure vessel type:  25-L Teflon-lined stainless steel aquaria containing 15-L of test solution. The water depth was approximately 18 cm.

- Number of replicates, fish per replicate:  Two replicates per treatment, 10 Fish per replicate

- Dilution water source:  Fresh water obtained from a well approximately 40 m deep. The water was passed through a sand filter to remove particles approximately 25 μm in diameter and was aerated. Prior to use the water was again filtered (0.45 μm) and passed through a UV steriliser to remove microorganisms.

- Dilution water chemistry:  Hardness 132 mg/L as CaCO3, Alkalinity 178 mg/L as CaCO3, Conductivity 323  mhos/cm        

- Vehicle/solvent and concentrations:  The solvent control and treatment groups contained 0.1 mL/L DMF

- Water chemistry in test:  DO, pH and temperature measured in each test chamber daily

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 75 ng/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No mortalities or other signs of toxicity were observed in any treatment

Reported statistics and error estimates:

There was no significant mortality in any treatment; statistical analysis was therefore not required.

Sublethal observations / clinical signs:

Table 1. Test results

Nominal concentration (ng/l)	Mean measured concentration (ng/l)	Percentage mortality after 24 hours	Percentage mortality after 48 hours	Percentage mortality after 72 hours	Percentage mortality after 96 hours
0 (Control)	-	0	0	0	0
0 (Vehicle control)	-	0	0	0	0
4.4	2.7	0	0	0	0
8.8	7.5	0	0	0	0
18	13.2	0	0	0	0
35	35.1	0	0	0	0
70	75.1	0	0	0	0

       

Validity criteria fulfilled:

yes

Conclusions:

A 96-hour LC50 value of >75 ng/L has been determined for the effects of the substance on mortality of Oncorhynchus mykiss. The results have been obtained under flow-through conditions and are expressed relative to mean measured concentrations of the substance.

Description of key information

HMDS: Short-term toxicity to fish: 96-h LC₅₀ 0.46 mg/l (mean measured concentration), mortality of Oncorhynchus mykiss.

L3: Short-term toxicity to fish: 96-h LC₅₀ >19 μg/l (measured, arith. mean; highest concentration tested), mortality of Oncorhynchus mykiss.

L4: Short-term toxicity to fish: 96-h LC₅₀ >6.3 μg/l (measured, highest concentration tested) mortality of Oncorhynchus mykiss.

L5: Short-term toxicity to fish: 96-h LC₅₀ >75 ng/l (mean measured concentration), mortality of Oncorhynchus mykiss.

Additional information

Constituent HMDS

A 96-hour LC₅₀ value of 3.02 mg/l has been determined for the effects of HMDS on mortality of Oncorhynchus mykiss based on nominal concentrations. A 96-hr LC₅₀ value of 0.46 mg/l has been re-calculated based on mean measured concentrations (Bayer, 1991). In view of the use of flow-through test conditions it is likely that the test organisms were exposed primarily to the parent substance.

 

Constituent L3

A 96-hour LC₅₀ value of >19 μg/l (measured) (highest concentration tested) has been determined for the effects of L3 on mortality of Oncorhynchus mykiss based on mean measured concentrations (DCC, 2007). In view of the use of flow-through test conditions it is likely that the test organisms were exposed primarily to the parent substance.

 

Constituent L4

A 96-hour LC₅₀ value of >6.3 μg/l (mean measured; highest concentration tested) has been determined for the effects of L4 on mortality of Oncorhynchus mykiss based on mean measured exposure concentrations (Dow Corning, 2008). In view of the use of flow-through test conditions it is likely that the test organisms were exposed primarily to the parent substance.

 

Constituent L5

A 96-hour LC₅₀ value of >75 ng/l has been determined for the effects of the substance on mortality of Oncorhynchus mykiss. The results have been obtained under flow-through conditions and are expressed relative to mean measured concentrations of L5 (DCC, 2010). In view of the use of flow-through test conditions it is likely that the test organisms were exposed primarily to the parent substance.