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Long-term toxicity to aquatic invertebrates

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Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
October 2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: This summary has a reliability of 2 because the results are estimated using a computer model that is appropriate for use with this hydrocarbon substance
Justification for type of information:
The aquatic toxicity was estimated by a QSAR, the Petrotox computer model (v 3.06). This model combines a partitioning model used to calculate the aqueous concentration of hydrocarbon components with the Target Lipid Model used to calculate acute and chronic toxicity of non-polar narcotic chemicals. Petrotox computes toxicity based on the summation of the aqueous-phase concentrations of hydrocarbon block(s) that represent a hydrocarbon substance and membrane-water partition coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.
Qualifier:
no guideline followed
Principles of method if other than guideline:
The aquatic toxicity was estimated by a QSAR, the Petrotox computer model (v 3.06). This model combines a partitioning model used to calculate the aqueous concentration of hydrocarbon components with the Target Lipid Model used to calculate acute and chronic toxicity of non-polar narcotic chemicals. Petrotox computes toxicity based on the summation of the aqueous-phase concentrations of hydrocarbon block(s) that represent a hydrocarbon substance and membrane-water partition coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.
GLP compliance:
no
Remarks:
The data were calculated by a computer model.
Specific details on test material used for the study:
No data
Analytical monitoring:
no
Details on sampling:
No data
Vehicle:
no
Details on test solutions:
No data
Test organisms (species):
Daphnia magna
Details on test organisms:
No data
Test type:
other: QSAR modeled data
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Hardness:
No data
Test temperature:
No data
pH:
No data
Dissolved oxygen:
No data
Salinity:
No data
Nominal and measured concentrations:
No data
Details on test conditions:
No data
Reference substance (positive control):
not required
Key result
Duration:
21 d
Dose descriptor:
NOELR
Effect conc.:
0.69 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Details on results:
No data
Results with reference substance (positive control):
No data
Reported statistics and error estimates:
No data

The composition used to run the Petrotox model is below, derived from the boundary compositions in the SIP for the substance;

 Carbon Number  n-P i-P  i-N  MoAr
 10 1.593   1.593  1.593  0.098
 11 2.007 2.007 2.007  0.123
 12  3.388  3.388  3.388  3.388
 13  3.613  3.613  3.613  3.613
14   5.902  5.902  5.902 0.361
 15  4.426  4.426  4.426  0.271
 16  4.426  4.426  4.426  0.271
 17  2.715 2.715  2.715   0.166
 18  0.188  0.188  0.188  0.012
 19  0.188  0.188  0.188  0.012
 20  0.188  0.188  0.188  0.012
 21  0.188  0.188  0.188  0.012
 22  0.188  0.188  0.188  0.012
 23  0.188  0.188  0.188  0.012
 24  0.188  0.188  0.188  0.012
 25  0.188  0.188  0.188  0.012
 26  0.188  0.188  0.188  0.012
 27  0.188  0.188  0.188  0.012
 28  0.188  0.188  0.188  0.012
 29  0.188  0.188  0.188  0.012
 30  0.188  0.188  0.188  0.012
Validity criteria fulfilled:
yes
Conclusions:
The estimated freshwater invertebrate 21-day NOELR (Lowest Observed Effect Loading Rate) value is 0.69 mg/l based on reproduction.
Executive summary:

The aquatic toxicity was estimated using the Petrotox computer model, which combines a partitioning model used to calculate the aqueous concentration of hydrocarbon components as a function of substance loading with the Target Lipid Model used to calculate acute and chronic toxicity of non-polar narcotic chemicals. Petrotox computes toxicity based on the summation of the aqueous-phase concentrations of hydrocarbon block(s) that represent a hydrocarbon substance and membrane-water partitioning coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.

The estimated freshwater invertebrate 21-day NOELR (Lowest Observed Effect Loading Rate) value is 0.69 mg/L based on reproduction.

Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
Not applicable, calculated value
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: This summary has a reliability of 2 because the results are estimated using a computer model that is appropriate for use with this hydrocarbon substance.
Justification for type of information:
Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint.
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
no guideline followed
Principles of method if other than guideline:
The aquatic toxicity was estimated by a QSAR, the Petrotox computer model. This model combines a partitioning model used to calculate the aqueous concentration of hydrocarbon components with the Target Lipid Model used to calculate acute and chronic toxicity of non-polar narcotic chemicals. Petrotox computes toxicity based on the summation of the aqueous-phase concentrations of hydrocarbon block(s) that represent a hydrocarbon substance and membrane-water partition coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.
GLP compliance:
no
Remarks:
The data were calculated by a computer model
Analytical monitoring:
not required
Vehicle:
no
Test organisms (species):
Daphnia magna
Test type:
other: QSAR modeled data
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Key result
Duration:
21 d
Dose descriptor:
NOELR
Effect conc.:
0.162 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Validity criteria fulfilled:
yes
Conclusions:
The estimated freshwater invertebrate 21-day NOELR (No Observed Effect Loading Rate) value is 0.162 mg/L based on reproduction.
Executive summary:

The aquatic toxicity was estimated using the Petrotox computer model, which combines a partitioning model used to calculate the aqueous concentration of hydrocarbon components as a function of substance loading with the Target Lipid Model used to calculate acute and chronic toxicity of non-polar narcotic chemicals. Petrotox computes toxicity based on the summation of the aqueous-phase concentrations of hydrocarbon block(s) that represent a hydrocarbon substance and membrane-water partitioning coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.

The estimated freshwater invertebrate 21-day NOELR (No Observed Effect Loading Rate) value is 0.162 mg/l based on reproduction.

Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from 2004-05-28 to 2004-08-11
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented guideline study
Justification for type of information:
Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint.
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
according to guideline
Guideline:
OECD Guideline 211 (Daphnia magna Reproduction Test)
GLP compliance:
yes
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
No test surrogate or analogue material
Analytical monitoring:
yes
Details on sampling:
Samples were analyzed for each new test and control solution on days 0, 7, 14, and 20 (2 individual replicates) and the corresponding old solutions (3 individual replicates) on days 1, 8, 15 and 21.
Microliter aliquots of hydrocarbons, C10 -C13, n-alkanes, isoalkanes,cyclics, aromatics (2 -25%) and 2-methylnaphthalene internal standard solutions in acetone were spiked directly into 10 mL gas tight syringes containing reconstituted water. The syringe contents were transferred to headspace (ca. 20 mL) sample vials containing 5 g sodium sulfate. The vials were crimp sealed and shaken to solubilize the sodium sulfate prior to being placed on the headspace sampler for analysis.
Vehicle:
no
Details on test solutions:
Individual treatments were prepared by adding the appropriate amount of test substance to 13 l of vehicle/dilution water in glass aspirator bottles (capacity 13.8 l). The test substance was added to the water in the aspirator bottles using stainless stell and glass syringes. The syringes were weighed with and without the test substance to determine the actual loading rate. The mixing vessels were sealed with foil covered rubber stoppers; The mixtures were stirred using a 4.4% (of the static liquid depth) vortex for approximately 24 hours on magnetic stirplates with Teflon coated stirbars at room temperature (22.6°C, S.D. 0.3°C). The stirbars were 1.3 cm in diameter and 7.8 cmlong. The depth of solution was 34 cm and the mixing speed was approximately 200 rpm. As stirring initiated and after stirring, all treatments appeared clear/colourless with test substance observed floating at the surface. The mixtures were allowwed to equilibrate to test temperature in a waterbath at 21.8 °C for approximately 1 hour without stirring before removing the WAFs for testing. New WAFs were prepared daily for the renewals.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna
- Source: Cultured at the test facility. Original culture supplied by Aquatic Biosystems, Inc., Fort Collins, Colorado. Stater culture received on 2002-04-11.

HUSBANDRY and ACCLIMATION
Eight daphnids were kept in 1-liter glass culture beakers with approximately 800 ml of reconstituted water (study vehicle/dilution water). The culture chamber was maintained at 20 +/- 1°C under a 16 hour light 8 hour dark photoperiod (10 - 20 foot/candles, 108 - 215 Lux). Day 0 cultures were started daily (at least 5 days per week) using 8 <24h old neonates from culture beakers between 12 and 18 days old, exhibiting <=20% adult immobillization. Cultures were transferred to fresh reconstituted water on regular intervals to ensure that <=24h old neonates are available for studies and to start new cultures.
Cultures of Daphnia magna were fed Pseudokirchneriella subcapitata (approximately 4.5 x 10e+5 cells/ml) and 4.0 ml of a yeast/salmon starter/wheat grass (YTC) mixture per 800 ml of reconstituted water (vehicle/dilution water) daily (5 days per week at a minimum). YTC and algae were supplied by Aquatic Biosystems, Inc., Fort Collins, Colorado.

EXPOSURE
Number: 60
Sex: Female
Age at initiation of exposure: <24h old, taken from 14-day old parents. The pool of neonates had <=10% daily immobilization on the experimental start day.
Daphniids were fed daily by adding 0.5 ml of a 1.3 x 10e+8 cells/ml suspension of Pseudokirchneriella subcapitata to provide approximatley 5.2 x 10e+5 cells/ml. Test organisms were also fed during renewals with 0.05 ml of a 2.5 g/l Microfeast PZ-20 suspension. Total organis carbon analysis of 125 ml of the vehicle/dilution water with 0.5 ml of algae and 0.05 ml Microfeast PZ-20 suspension contained approximatley 0.1 mg C after substracting the carbon content of the vehicle/dilution water. Since the test chambers contained only one daphnid, this equates to approximately 0.1 mg C per daphnid per day. The algae were supplied by Aquatic biosystems, Inc., Fort Collins, Colorado. The Microfeast PZ-20 was supplied by Salt Creek, Salt Lake City, Utah.
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Post exposure observation period:
No post exposure
Test temperature:
Mean test temperature: 20.1°C (S.D. = 0.3), continuously monitored by computer in the test area.
pH:
75-8.1
Dissolved oxygen:
6.8-8.6 mg/l
Nominal and measured concentrations:
Loading rates : 0, 0.12, 0.28, 0.65, 1.4, 3.1 mg/l
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: no headspace
The test chambers were 125-ml capacity clear glass bottles containing approximately 125 ml of solution (no headspace). The test chambers were sealed with foil lined screww type cap to minimize contamination, evaporation and/or volatilization.
- Aeration: no aeration
- Renewal rate of test solution (frequency/flow rate): Test solutions were renewed daily. A separate set of bottles was used on a rotating basis for renewals. Feed was first added to each bottle. There were then filled with the appropriate WAF and immediately capped. The adult D.magna from the old test solution were transferrred to their respective test chamber using a glass pipette, minimizing the amount of time the chambers were left uncapped. The volume of solution transferred was minimized.
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10
- Biomass loading rate: 1 daphnid par 125 ml

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water (see § Any other information on materials and methods below)
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod:16h light/8 hours dark
- Light intensity: 17 to 18 µE.me-2.se-1

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Immobilization at 24-h intervals
- Presence, appearance and number of neonates daily
Reference substance (positive control):
no
Duration:
21 d
Dose descriptor:
EL10
Effect conc.:
0.316 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks on result:
other: 95% Lower CI = 0.196 mg/l
Key result
Duration:
21 d
Dose descriptor:
EL50
Effect conc.:
1.19 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks on result:
other: 95% Lower CI = 0.980 mg/l
Duration:
21 d
Dose descriptor:
EL10
Effect conc.:
0.879 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
immobilisation
Remarks:
(adults)
Remarks on result:
other: 95% CI = 0.243-1.24 mg/l
Duration:
21 d
Dose descriptor:
EL50
Effect conc.:
1.62 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
immobilisation
Remarks:
(adults)
Remarks on result:
other: 95% CI = 1.26-2.51 mg/l
Duration:
21 d
Dose descriptor:
LOELR
Effect conc.:
0.65 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Key result
Duration:
21 d
Dose descriptor:
NOELR
Effect conc.:
0.28 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Duration:
21 d
Dose descriptor:
LOELR
Effect conc.:
3.1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
immobilisation
Remarks:
(adults)
Duration:
21 d
Dose descriptor:
NOELR
Effect conc.:
1.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
immobilisation
Remarks:
(adults)
Duration:
21 d
Dose descriptor:
LOELR
Effect conc.:
> 1.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Remarks:
Adult length
Duration:
21 d
Dose descriptor:
NOELR
Effect conc.:
1.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Remarks:
Adult length
Duration:
21 d
Dose descriptor:
EC10
Effect conc.:
0.109 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks on result:
other: 95% Lower CI = 0.054 mg/l
Key result
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
0.328 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks on result:
other: 95% Lower CI = 0.280 mg/l
Duration:
21 d
Dose descriptor:
EC10
Effect conc.:
0.248 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
immobilisation
Remarks:
(adults)
Remarks on result:
other: 95% CI = 0.061-0.341 mg/l
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
0.423 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
immobilisation
Remarks:
(adults)
Remarks on result:
other: 95% CI = 0.339-0.732 mg/l)
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
0.203 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
reproduction
Key result
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.097 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
reproduction
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
0.833 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
immobilisation
Remarks:
(adults)
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.372 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
immobilisation
Remarks:
(adults)
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
> 0.372 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth
Remarks:
Adult length
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.372 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth
Remarks:
Adult length
Details on results:
See below tables 2-4
Results with reference substance (positive control):
No reference substance
Reported statistics and error estimates:
The reproductive Effect Loading (EL) and Effect Concentration (EC) values were calculated using the Power Model of the Benchmark Dose (BMD) method. The adult immobilization Effect Loading (EL) and Effect Concentration (EC) values were determined using a maximum likelihood analysis based on D. J. Finney,1971. The NOELR and NOEC values were determined using Wilcoxon Rank Sum with Bonferroni Adjustment for the growth data and a t-test with Bonferroni Adjustment to analyze the reproduction data, and Fisher's Exact Test for the adult immobilization data. TOXSTAT software10 was
used to determine the NOELR and NOEC values.

Table2 - Analytical chemistry results

 

Nominal concentration (mg/l)

Replicate

Measured concentrations (mg/l)

Average

Day0

New

Day 1

Old

Day 7

New

Day 8

Old

Day 14

New

Day 15

Old

Day 20

New

Day 21

Old

Control

1

0

0

0

0

0

0

0

0

0

2

0

0

0

0

0

0

0

0

3

0

0

0

0

0

0

0

0

0.12

1

0.0417

0.0337

0.0357

0.0306

0.0451

0.0334

0.0403

0.0358

0.0390

±0.0038

2

0.0456

0.0421

0.0389

0.0377

0.0429

0.0405

0.0398

0.0393

3

n/a

0.0384

n/a

0.0376

n/a

0.0417

n/a

0.0383

0.28

1

0.105

0.0905

0.105

0.0916

0.110

0.0849

0.120

0.0907

0.0969

±0.0133

2

0.113

0.0852

0.102

0.0880

0.109

0.0893

0.121

0.0711

3

n/a

0.0846

n/a

0.0858

n/a

0.0907

n/a

0.0997

0.65

1

0.215

0.186

0.225

0.189

0.236

0.217

0.230

0.175

0.203

±0.021

2

0.205

0.179

0.209

0.191

0.231

0.218

0.203

0.172

3

n/a

0.179

n/a

0.183

n/a

0.222

n/a

0.189

1.4

1

0.407

0.334

0.376

0.362

0.365

0.382

0.380

0.323

0.372

±0.036

2

0.434

0.373

0.417

0.377

0.425

0.358

0.373

0.285

3

n/a

0.333

n/a

0.395

n/a

0.382

n/a

0.354

3.1

1

0.904

0.729

No samples due to complete immobilization

0.833

±0.085

2

0.36

0.791

3

n/a

0.807

 

 

Table 3- Reproduction, survival and length endpoints

21-day effect loading (EL10and EL50) based on reproduction

 

EL10

EL50

 

0.316 mg/l (0.196 mg/l)*

1.19 mg/l (0.980 mg/l)*

 

21-day effect loading (EL10and EL50) based on adult immobilization

 

EL10

EL50

 

0.879 mg/l (0.243-1.24 mg/l)**

1.62 mg/l (1.26-2.51 mg/l)**

 

Reproduction

Adult immobilization

Adult length

LOELR

NOELR

LOELR

NOELR

LOELR

NOELR

0.65 mg/l

0.28 mg/l

3.1 mg/l

1.4 mg/l

>1.4 mg/l

1.4 mg/l

 

21-day effect concentration (EC10and EC50) based on reproduction

 

EC10

EC50

 

0.109 mg/l (0.054 mg/l)*

0.328 mg/l (0.280 mg/l)*

 

21-day effect concentration (EC10and EC50) based on adult immobilization

 

EC10

EC50

 

0.248 mg/l (0.061-0.341 mg/l)**

0.432 mg/l (0.339-0.732 mg/l)**

 

Reproduction

Adult immobilization

Adult length

LOEC

NOEC

LOEC

NOEC

LOEC

NOEC

0.203 mg/l

0.097 mg/l

0.833 mg/l

0.372 mg/l

>0.372 mg/l

0372 mg/l

 

* 95% Lower Confidence Interval (the statistical program used does not calculate an upper C.I.)

** 95% Confidence Interval

 

Table 4- Summary of survival, reproduction and length results

Loading rate (mg/l)

Adult immobilization (%)

Neonates per adult

Adult average length (mm)

0

10

139

4.0

0.12

10

149

4.0

0.28

0

143

4.0

0.65

20

101

3.7

1.4

40

61

3.7

3.1

100

n/a

n/a

 

Validity criteria fulfilled:
yes
Conclusions:
Chronic toxicity results are expressed as the Effect Loading 50 (EL50), and Effect Concentration 50 (EC50); which are the loading rte and concentration which do not exhibit a statistical difference in reproductive output from the control.

The EL50 based on reproduction was 1.2 mg/l. The EC50 based on reproduction was 0.328 mg/l. Reproduction was more sensitive than growth and survival, resulting in a NOELR of 0.28 mg/l and a NOEC of 0.097 mg/l.
Executive summary:

This study was conducted to assess the chronic affects of the water-accomodated fractions (WAFs) of hydrocarbons, C10 -C13, n-alkanes, isoalkanes,cyclics, aromatics (2 -25%) (MRD-04 -991), to the daphnid, Daphnia magna, in a 21-day semi-static (renewal) test conducted according to OECD guideline 211.

Individual treatments were prepared by adding the appropriate amount of test substance to 13 l of vehicle/dilution water in glass aspirator bottles (capacity 13.8 l) and stirring on magnetic stirplates with a vortex of approximately 4% of the static liquid depth for approximately 24 hours. Approximately 1 hour after stirring was hakted, the aqueous portions (water accommodated fractions) of each treatment solution were removed for testing. The actual loading rates were 0 (control), 0.12, 0.28, 0.65, 1.4 and 3.1 mg/l. The mean measured concentrations were ND (Not detected; control), 0.039, 0.097, 0.203, 0.372 and 0.833 mg/l.

Ten replicates per treatment were tested. One <24 -hour old daphnid was added to each replicate. Replicate chambers were 125 ml capacity glass bottles, closed using screw-type tops with foil liners (the chamber contained no headspace). Water quality parameters (temperature, pH, and dissolved oxygen) were within acceptable limits throughout the testing period. Observations for immobilization were performed and recorded at approximately 24 -hour intervals after the begining of the test. The adults were transferrred to fresh solution daily and the numbers recorded. The control daphnids released their first brood on day 8 and 9. The coefficient of variation for control fecundity was 17%. At the end of the test, the total number of living offspring produced per live parent animal was detrmined. Adult organisms were measured (body length excluding the anal spine) at termination in order to determine if growth effects occurred.

Chronic toxicity results are expressed as the Effect Loading 50 (EL50), and Effect Concentration 50 (EC50); which are the loading rte and concentration which do not exhibit a statistical difference in reproductive output from the control.

The EL50 based on reproduction was 1.2 mg/l. The EC50 based on reproduction was 0.328 mg/l. Reproduction was more sensitive than growth and survival, resulting in a NOELR of 0.28 mg/l and a NOEC of 0.097 mg/l.

Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
19-Mar-2003 to 9-Apr-2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was given a reliability rating of 1 because it followed a standard test guideline, which describes a procedure to evaluate this endpoint, and the results were reviewed for reliability and assessed as valid. The study was also conducted under GLP.
Justification for type of information:
Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint.
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 211 (Daphnia magna Reproduction Test)
Principles of method if other than guideline:
Followed Part 2 of OECD 202 test guideline.
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
Samples were removed from the Control and test concentrations 1000, 2500, 5000, and 10000 mg/l at test initiation (0-hours) and at 48-hours of the preliminary test. Samples were also removed from the control and 2500 and 5000 mg/l concentrations on Day 0, 7, 14, and 20 of the main study. Samples were stored at -18deg C until analysis.
Vehicle:
no
Details on test solutions:
Test solutions were prepared as Water Accommodated Fractions (WAF). The test substance was added to daphnia media, and stirred for 23 hours with a magnetic stirrer until equilibrium. The mixing was done at a slow enough speed as to not cause dispersion or emulsification of the undissolved test substance. The solution was allowed to stand for approximately 1 hour, to allow phase separation, before being carefully siphoned out via a glass tube (added prior to the addition of the test substance). Renewal of the test WAF was conducted every 48 hours.
Test organisms (species):
Daphnia magna
Details on test organisms:
Daphnia magna - Clone 5 (Crustacea, Daphniidae)
Origin - German Environmental Ministry
Pre-treatment - the animals are cultivated in a climate controlled room
(light/dark = 14h / 10h; illumination: GroLux fluorescent tubes).
The animals were fed with algae (Desmodesmus subspicatus).
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Test temperature:
19.7 to 20.8 deg C
pH:
8.0 to 8.2
Dissolved oxygen:
8.3 to 8.8 mg/l
Salinity:
freshwater
Nominal and measured concentrations:
Nominal concentrations were: 0, 2500, 5000 mg/l.

Concentration analysis (TOC) of the control and 2500 and 5000 mg/l test concentrations gave results of <10 mg/l. Indicating very low solubility of the test substance.
Details on test conditions:
40 animals/conc. (10 each per 4 replicates)
400 ml of solution in 800 ml glass beakers.
14h light / 10h dark - GroLux fluorescent tubes.
Animals were fed daily with algae (Desmodesmus subspicatus)
Reference substance (positive control):
no
Duration:
21 d
Dose descriptor:
EL50
Effect conc.:
> 5 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
immobilisation
Remarks:
Parental generation
Duration:
21 d
Dose descriptor:
EL50
Effect conc.:
< 2 500 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Duration:
21 d
Dose descriptor:
NOELR
Effect conc.:
< 2 500 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Key result
Duration:
21 d
Dose descriptor:
EL50
Effect conc.:
ca. 1 400 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: inhibition of reproduction
Key result
Duration:
21 d
Dose descriptor:
NOELR
Effect conc.:
ca. 17 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: inhibition of reproduction
Details on results:
Immobilisation of Parental Generation: (at end of test)
Control - 10%
2500 mg/l - 20%
5000 mg/l - 28%

Date of first appearance of young (F1):
Control - 8d
2500 mg/l - 10d
5000 mg/l - 12d

Number of living young produced (at end of test):
Control - 712
2500 mg/l - 265 (62.8% inhibition of reproduction vs. control)
5000 mg/l - 177 (75.1% inhibition of reproduction vs. control)

Number of dead young produced (at end of test):
Control - 10
2500 mg/l - 16
5000 mg/l - 27
Reported statistics and error estimates:
Graphic evaluation on probability paper gave approximate results of the inhibition of reproduction.
Validity criteria fulfilled:
yes
Conclusions:
The chronic toxicity of Hydrocarbons, C11 -C20, n-alkanes, isoalkanes, cyclics, aromatics (2 -30%) as measured by reproductive success to the water flea (Daphnia magna) was evaluated in freshwater. Hydrocarbons, C11 -C20, n-alkanes, isoalkanes, cyclics, aromatics (2 -30%) showed toxic effects as a Water Accommodated Fraction (WAF) with a 21 -day EL50 of approximately 1400 mg/l and an NOELR of 17 mg/l (based on inhibition of reproduction).
Executive summary:

The chronic toxicity of Hydrocarbons, C11 -C20, n-alkanes, isoalkanes, cyclics, aromatics (2 -30%) as measured by reproductive success to the water flea (Daphnia magna) was evaluated in freshwater. Hydrocarbons, C11 -C20, n-alkanes, isoalkanes, cyclics, aromatics (2 -30%) showed toxic effects as a Water Accommodated Fraction (WAF) with a 21 -day EL50 of approximately 1400 mg/l and an NOELR of 17 mg/l (based on inhibition of reproduction).

Description of key information

There is no experimental data available for Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, 2-25% aromatics. Data is read across from structural analogues such as Hydrocarbons, C9-C14 aliphatics, 2-25% aromatics and Hydrocarbons, C14-C20 aliphatic, 2-30% aromatics.

Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint. Petrotox has also been run for the substance..

 

The estimated freshwater invertebrate 21-day NOELR (No Observed Effect Loading Rate) value for Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2 -25%) determined using the Petrotox computer model (HCSC, 2018) is 0.69 mg/L in Daphnia magna, based on reproduction.

A study was conducted to assess the chronic effects of the water-accommodated fractions (WAFs) of hydrocarbons, C10-C13, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) on the daphnid, Daphnia magna, in a 21-day semi-static (renewal) test. The EL50 based on reproduction was 1.2 mg/L. The EC50 based on reproduction was 0.328 mg/L. Reproduction was more sensitive than growth and survival, resulting in a NOELR of 0.28 mg/L and a NOEC of 0.097 mg/L.

 

Hydrocarbons, C11 -C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) did not cause toxicity in a 21-day toxicity study with Daphnia magna following standard test guidelines at a nominal loading of 1400 mg/L, with a NOELR of 17 mg/L (based on inhibition of reproduction). These results indicate that hydrocarbons, C11-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) is not expected to be chronically toxic to freshwater invertebrates.

 

The estimated freshwater invertebrate 21-day NOELR (No Observed Effect Loading Rate) value for Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) determined using the Petrotox computer model (CONCAWE, 2010) is 0.162 mg/L in Daphnia magna, based on reproduction.

 

These data are used as read across data for Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, 2-25% aromatics.

Key value for chemical safety assessment

Additional information

A study was performed on Daphnia magna exposed to hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%). The 21-d NOELR based on reproduction was found to be 0.28 mg/L.

 

Hydrocarbons, C11 -C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) did not cause toxicity in a 21-day toxicity study with Daphnia magna following standard test guidelines at a nominal loading of 1400 mg/L, with a NOELR of 17 mg/L (based on inhibition of reproduction).These results indicate that hydrocarbons, C11-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) is not expected to be chronically toxic to freshwater invertebrates.

 

The estimated freshwater invertebrate 21-day NOELR (No Observed Effect Loading Rate) value for Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) determined using the Petrotox computer model (CONCAWE, 2010) is 0.162 mg/L in Daphnia magna, based on reproduction.

 

These data are used as read across data for Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, 2-25% aromatics.