Hydrocarbons, C17-C19, n-alkanes, <2% aromatics

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March to November 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This robust summary has a reliability rating of 1 because the study followed a standard guideline, followed GLP guidelines, and was conducted without deviations that would invalidate the study.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

An equilibration study was conducted prior to the study to determine the length of time needed to develop water accommodated fractions (WAFs) at the 1000 mg/L loading level. The aqueous phase of the WAF was analyzed after 1, 24, 48, and 96 hours of stirring. In all samples, the quantity of test substance in solution was less than the limit of detection (0.5 mg/L). Further analysis of test substance in test media a loading level of 1 g/L also showed no detectable amounts of test substance. Consequently, analysis of treatment solutions from the definitive study were not conducted.

Vehicle:

no

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

Organisms used in the test were from a laboratory culture, originally derived from a strain (ATCC 22662) obtained from the American Type Culture Collection, Maryland, Ohio, USA.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

None

Test temperature:

23 to 25 degrees C

pH:

7.2 to 8.8

Nominal and measured concentrations:

The nominal loading rate was 1000 mg/L. A control was also tested.

Details on test conditions:

The study was conducted in sealed test systems with no headspace that were not renewed during the study. The test systems used were 300 ml glass Erlenmeyer flasks that were complely filled with test media. Six replicate test systems were established for the treatment level and control. Control and treatment systems were innoculated with a concentration of 5000 cells/ml. Test systems were incubated under constant illumination (approximately 3000 lux) on an orbital incubator.

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Validity criteria fulfilled:

yes

Conclusions:

Growth of an alga culture, Pseudokirchnerella subcapitata, as measured by biomass and growth rate, exposed to a 1000 mg/L water accommodated fraction of the test substance was not inhibited when compared to the control after a 72-hour exposure. Therefore, the 72-hr EL50 and NOELR values for these two endpoints are reported as >1000 mg/L and 1000 mg/L, respectively.

Executive summary:

Growth of an alga culture, Pseudokirchnerella subcapitata, as measured by biomass and growth rate, exposed to a 1000 mg/L water accommodated fraction of the test substance was not inhibited when compared to the control after a 72-hour exposure. Therefore, the 72-hr EL50 and NOELR values for these two endpoints are reported as >1000 mg/L and 1000 mg/L, respectively.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No inhibitory effect even with the highest concentration. EL50 not reached. Based on WAFs.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum)

Deviations:

no

Principles of method if other than guideline:

Guideline study

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 material is tested

Analytical monitoring:

no

Details on sampling:

Not applicable (no analytical monitoring)

Vehicle:

no

Details on test solutions:

The test solutions were prepared as water accomodated fractions (WAFs). They were prepared by direct addition of the required nominal amounts, followed by stirrring for approximately 20 hours. The preparations were then allowed to stand for appromately 1 h, before withdrawing a sample by siphon from the middle of the water phase, avoiding incorporation of floating/settled material.

Test organisms (species):

Skeletonema costatum

Details on test organisms:

TEST ORGANISM
- Common name: Skeletonema costatum
- Age of inoculum (at test initiation): at least 4 days
- Method of cultivation: Stock culture in laboratory at ca. 20°C at constant illumination

ACCLIMATION
- Acclimation period: 4 days
- Culturing media and conditions: same as test

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

No post exposure observation

Hardness:

Not relevant (seawater study)

Test temperature:

19.5 °C

pH:

8.07 - 8.81

Dissolved oxygen:

No data provided

Salinity:

No data provided

Nominal and measured concentrations:

10096, 20063, 30025, 60085 and 100204 mg/L (ppm). These concentrations are based after weighing the test substance in the algal culture medium.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: closed (all flasks looselys covered with aluminium foil caps)
- Material, size, headspace, fill volume: borosilicate glass conical flasks, 80 mL test medium
- Aeration: Not provided in the study report
- Initial cells density:10^4 cells/ml
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 4

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: No
- Adjustment of pH: Yes
- Photoperiod: continuous light
- Light intensity and quality: 4 x 40W tubes mounted at a distance of 40 cm directely above the test area

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: counting chamber

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8

Reference substance (positive control):

yes

Remarks:

Water-soluble chemical 3',5-dichlorophenol

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Not relevant

Details on results:

- Exponential growth in the control (for algal test): yes

Results with reference substance (positive control):

72 h LC50 = 3.83 mg/L

Reported statistics and error estimates:

Not relevant as the EL50 is greater than the highest tested concentration.

No remarks

Validity criteria fulfilled:

yes

Conclusions:

No growth inhibition at concentrations up to 10,000 mg/L

Executive summary:

The test procedure followed is described in the ISO/DIS 10253 « Water quality » - Marine algal growth inhibition test with Skeletonema costatum and Phaeodactylum tricornutum”, 1991.

Skeletonema costatum was used as test organism.

The organisms are exposed to Water Accomodated Fractions (WAFs) of test substance H383 -96.

The exposure of Skeletonema costatum to concentrations up to 10,000 mg/l for 72 h does not inhibit algal growth (based on growth rate measurements).

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study complies with ISO 10253:2006 testing method. However, the control of the Water Accomodated Fraction preparation is not mentioned, especially which the compounds present in the fraction and its stability. Also, an important incoherence in the results are hardly discussed (significant effect at 30.2 and 99.1 mg/L WAF but the NOEC is claimed at 993 mg/L WAF). MSDS provided.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum)

Version / remarks:

NS-EN ISO 10253, 1998

Deviations:

no

Principles of method if other than guideline:

Guideline study

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 material is tested

Analytical monitoring:

no

Details on sampling:

Not applicable (no analytical monitoring)

Vehicle:

no

Details on test solutions:

The solubility of the test substance was reported to be <1 mg/L in water. Water accomodated fractions (WAFs) were prepared individually by stirring the appropriate amounts of the test substance in growth medium. The solutions were stirred with a spin-bar for 20 hours. Samples for testing were taken from the mid of the water phase with a peristaltic pump. Test results relate to these water accomodated fractions.

Test organisms (species):

Skeletonema costatum

Details on test organisms:

TEST ORGANISM
- Common name: Skeletonema costatum
- Source (laboratory, culture collection): Oslo fiord (1962)
- Strain: NIVA-BAC1
- Method of cultivation: incubated ca. 20°C under continuous light (>50 µE/m-2/sec-1)

ACCLIMATION
- Culturing media and conditions: same as test

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

No post-exposure observation

Hardness:

Not relevant (seawater study)

Test temperature:

20 ±2°C

pH:

8.2-8.3

Dissolved oxygen:

No data provided

Salinity:

33.9 per thousand

Nominal and measured concentrations:

2.4, 9.7, 32.2, 99.1, 320, 993 and 3200 mg/l (nominal loading rates).

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 100 mL flat-bottomed flasks on an orbital shaker
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: the seawater was used as basis for the growth medium. The water was filtered through a GF/C filter, and briefly heated to about 75°C prior to use.

OTHER TEST CONDITIONS
- Sterile test conditions: No
- Adjustment of pH: No
- Photoperiod: continuous light
- Light intensity and quality: >50 µE/m-2/sec-1
- Salinity (for marine algae): 33.9 per thousand

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Algal growth measured by fluorescence: Turner Designs, Model 10 fluorimeter


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.33

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol 97%

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 3 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: (based upon nominal loading rates)

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

993 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: (based upon nominal loading rates)

Details on results:

- Exponential growth in the control (for algal test): yes
- Any stimulation of growth found in any treatment: the 72 h NOELR was 993 mg/L but a significant inhibition of growth rate was observed at 32.2 and 99.1 mg/L (nominal loading rates)

Results with reference substance (positive control):

Test concentration: 3 x 1.5 mg/L
Inhibition (mean value): 1.04 - 1.25 - 1.40 (growth rate)
- pH: at start 8.3 - at end 8.2

Reported statistics and error estimates:

Not relevant

During the test, the fluorescence (growth measurements) was recorded after 24, 48 and 72 +/- 2 hours and the pH was recorded at start and at end of test.

Validity criteria fulfilled:

yes

Conclusions:

The 72 hour EL50 was >3200 mg/L (based upon loading rates).

Executive summary:

The solubility of the test substance was reported to be < 1 mg/L in water. WAF were prepared by stirring the product in growth medium for 20 hours, followed by standstill for 4 hours. Samples for testing were taken from the mid of the water phase. Test cultures of 50 mL were incubated in 100 mL flat-bottomed flasks on an orbital shaker, 3 replicates for each concentration. Test substance concentrations from 2.4 mg/L to 3200 mg/L (based upon nominal loading rates) were inoculated to about 2000 cells/mL from an exponentially growing inoculum culture.

The test was run for about 72 hours under continuous light from fluorescent tubes of universal natural white type, at a temperature of 18.9 - 20.1°C. Six flat-bottomed flasks contained blank and three flasks contained the reference substance 3.5 -Dichlorophenol at 1.5 mg/L. Sub-samples of 5 mL were taken from the test flasks each day for growth measurements.

The inhibitory effect on the growth of Skeletonema costatum is expressed as the concentration of a product giving 50% of growth rate (ErC₅₀). The programme also calculates concentrations inhibiting growth rate 10% and 90% (EC₁₀ and EC₉₀). However, the results are based on nominal loadings. Therefore they are expressed here as EL (Effective Loading), instead of EC (Effective Concentration) as in the original report study.

The 72 hour EL₅₀ with DEV 2006 -16 was > 3200 mg/L (based on nominal laoding rates).

Calculation of NOELR is done by single-factor ANOVA followed by Dunnetts procedure for comparing each concentration mean with the control mean.

The 72 h NOELR was 993 mg/L but a significant inhibition of growth rate was observed at 32.2 and 99.1 mg/L (based on nominal loading rates).

All the criteria for test acceptance were fulfilled.

72h-EL₅₀ > 3200 mg/L (based upon nominal loading rates)

72h-NOELR = 993 mg/L (based upon nominal loading rates)

Description of key information

As C14-20 Aliphatics (≤2% aromatic) are poorly soluble in water, most of the studies are performed using Water accommodated fractions (WAFs) and all the results are based on nominal loadings. Thus, the values indicated below as NOECs are actually NOELRs (No observed effect loading rates). No study could lead to the calculation of EL₅₀.

 

Fourteen study reports were available for this end-point, all dealing with the toxicity of the substance Hydrocarbons, C14-C18, n-alkanes, isoalkanes, cyclics, < 2% aromatics on algae growth rate. All the studies used the marine species Skeletonema costatum. None of the studies allowed calculating 48h-EL₅₀ that was never reached. All LL₅₀ are superior to 10000 mg/L based on WAF studies.

.

Growth of an alga culture, Pseudokirchnerella subcapitata, as measured by biomass and growth rate, exposed to a 1000 mg/L water accommodated fraction of Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics was not inhibited when compared to the control after a 72-hour exposure. Therefore, the 72-hr EL₅₀ and NOELR values for these two endpoints are reported as >1000 mg/L and 1000 mg/L, respectively.