Pentyl D-glucoside

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:

read-across from supporting substance (structural analogue or surrogate)

Remarks:

Summary of available data used for the assessment of this endpoint for the target substance.

Adequacy of study:

key study

Justification for type of information:

Refer to the analogue approach justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

freshwater

Remarks on result:

other:

Remarks:

Source: RA-A, CAS 31387-97-0, Inst. Techn. FCBA, 2010

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 51 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks:

freshwater

Remarks on result:

other:

Remarks:

Source: RA-A, CAS 31387-97-0, Inst. Techn. FCBA, 2010

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

freshwater

Remarks on result:

other:

Remarks:

Source: RA-A, CAS 31387-97-0, Inst. Techn. FCBA, 2010

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 51 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks:

freshwater

Remarks on result:

other:

Remarks:

Source: RA-A, CAS 31387-97-0, Inst. Techn. FCBA, 2010

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

435 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

Water Accomodated Fraction (WAF)

Basis for effect:

growth rate

Remarks:

saltwater

Remarks on result:

other: 95% CL: 365 - 826 mg/L WAF

Remarks:

Source: RA-A, CAS 54549-24-5, 2003, S. costatum

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

180 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

Water Accomodated Fraction (WAF)

Basis for effect:

growth rate

Remarks:

saltwater

Remarks on result:

other:

Remarks:

Source: RA-A, CAS 54549-24-5, 2003, S. costatum

Conclusions:

The key effect concentrations retained for the assessment of the toxicity of the target sustance to aquatic freshwater algae are a NOEC (72 h) of ≥ 100 mg/L (nominal, based on test material) and an ErC50 (72 h) of > 100 mg/L (nominal, based on test material) or > 51 mg/L (based on active ingredient) according to the available read-across data (OECD 201, P. subcapitata, CAS 31387-97-0).
The key effect concentrations retained for the assessment of the toxicity of the target sustance to aquatic saltwater algae are a NOEL (72 h) of 180 mg/L (nominal, based on test material) and an EL50 (72 h) of 435 mg/L (nominal, based on test material), according to the available read-across data (ISO 10253, S. costatum, CAS 54549-24-5).

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

13 - 22 February 1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test done under GLP and according to guideline, no chemical analysis were done. Certificate of analysis was added for identification of the test substance.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Principles of method if other than guideline:

No measurements of actual concentrations, no phys-chem data,

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

For the purpose of the definitive study the test material was prepared by a direct dispersion in water.
An amount of test material (1330 mg) was dispersed in culture medium and the volume adjusted to 500 mL to give a 2000 mg a.i./L stock solution, from which serial dilutions were made to give 125, 250, 500 and 1000 mg a.i./L stock solutions.
Aliquots (150 ml) of this stock solution were mixed with algal suspension (150 mL), to give the test concentrations of 62.5, 125, 250, 500 and 1000 mg a.i./L.

Triplicate test vessels were prepared for the 1000 mg a.i./L test concentration in order to enable the results obtained to be averaged to confirm the level of inhibition at the highest test concentration.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Liquid cultures of Scenedesmus subspicatus (CCAP 276/20) were obtained from the Culture Centre of Algae and Protozoa (CCAP) , Institute of Freshwater Ecology, Cumbria, U.K. Cultures were maintained in the laboratory by the periodic replenishment of culture medium. The culture was maintained in the laboratory at a temperature of 21 +/- 1 °C under continuous illumination (intensity approximately 7000 lux) and constant aeration.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

None

Hardness:

No specific data on hardness given

Test temperature:

24 +/- 1 °C

pH:

At the start 7.5, increasing to 10.1 at 72h

Dissolved oxygen:

No data

Nominal and measured concentrations:

Nominal Concentrations:
62.5 - 125 - 250 - 500 - 1000 mg/L

Details on test conditions:

250 mL glass conical flasks were used. Three flasks each containing 100 ml of solution were prepared for the control and each treatment group. The control group was maintained under identical conditions but not exposed to the test material.
Pre-culture conditions gave an algal suspension in log phase growth characterised by a cell density of 8.18 x 10^6 cells per mL. This suspension was diluted to a cell density of 2.11 x 10^4 cells per mL prior to use. At initiation of the study the culture
contained a nominal cell density of 10^4 cells per mL.

The flasks were covered with aluminium foil and incubated (Gallenkamp INR-401- 010W) at 24 +/- 1 °C under continuous illumination (intensity approximately 7000 lux) and constantly shaken at 100 rpm for 72 hours. Samples were taken at 0, 24, 48 and 72 hours and the cell densities determined by direct counting with the aid of a Coulter@ Multisizer I I particle counter.

The pH of each control and test flask was determined at initiation of the study and after 72-hours exposure. The temperature within the incubator was recorded daily.

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

125 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

780 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

180 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

biomass

Details on results:

Both the growth (r) and the biomass (b) of Scenedesmus subspicatus (CCAP 276120) were affected by the presence of the test material over the 72-hour exposure period. The EbC50 (72 h) is nominally 180 mg a.i./L and the ErC50 (0-72 h) was determined at 780 mg a.i./L.

Statistical analysis of the 0 - 72 hour growth rate data was carried out for the control and all test concentrations using one way analysis of variance. There were no statistically significant differences between the control and 62.5 and 125 mg ai/L test concentrations (P>=0.05), however all other test concentrations were significantly different (P < 0.01) and, therefore the "No Observed Effect Concentration" (NOEC) is given as nominally 125 mg ai/L.

The cell concentration of the control cultures increased by a factor of 55 during the test in line with the OECD Guideline that
states the enhancement must be at least by a factor of 16 after 72 hours:
Mean cell density of control at 0 hours : 1.4 x 10^4 cells/ml
Mean cell density of control at 72 hours : 7.75 x 10^5 cells/ml

All test and control cultures were inspected microscopically at 72 hours. There were no abnormalities detected in any of the control or test cultures at 62.5, 125 and 250 mg ai/L, however cell debris was observed at 500 and 1000 mg ai/L..

The pH values of the control cultures were observed to increase from pH 7.5 - 7.6 at 0 hours to pH 9.8 - 9.9 at 72 hours. This effect is considered to be due to the large number of cells in the log phase of growth respiring oxygen and producing carbonates and bicarbonates as part of
photosynthesis/respiration which in solution give rise to alkaline conditions. The pH deviation in the control cultures was in excess of that given in the Test Guidline (1.5 pH units after 72 hours). This is considered not to affect the integrity of the study given that the increase in control cell concentration was in excess of the enhancement factor of 16 stated in the OECD Guideline. The increase in pH observed over the 72-hour study period followed a concentration dependent pattern with the lower test material concentrations exhibiting a greater increase in pH . This effect is considered to be due to there being greater numbers of viable cells in the lower test concentrations and hence a greater production of carbonates and bicarbonates from photosynthesis/respiration.

Reported statistics and error estimates:

One way analysis of variance was carried out on the area under the growth curve data at 72 hours for the control and all test concentrations to determine any statistically significant differences between the test and control groups.

Inhibition algal growth and growth rate

Conc substance (in mg/L)	% inhibition growth	% inhibition growth rate
62.5	28	5
125	44	9
250	56	16
500	72	27
1000	103	91

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test material on the growth of Scenedesmus subspicatus has been investigated over a 72 hour period and gave an EbC50 (72 h) value of nominaly 180 mg a.i./L and an ErC50 (0 - 72 h) value of 780 mg a.i./L. The No Observed Effect Concentration at 72 hours was nominally 125 mg a.i./L.

Executive summary:

A study was performed to assess the effect of the test material on the growth of the green alga Scenedesmus subspicatus. The method followed that described in the OECD Guidelines for Testing of Chemicals (1984) No 201, "Alga, Growth Inhibition Test". Scenedesmus subspicatus was exposed to an aqueous dispersion of the test material at concentrations of 62.5, 125, 250, 500 and 1000 mg a.i./L (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 24 +/- 1 °C. Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group. Exposure of Scenedesmus subspicatus to the test material gave a nominal EbC50 (72 h) value of 180 mg a.i./L and an ErC50 (0 - 72 h) value of 780 mg a.i./L. The No Observed Effect Concentration was found to be nominally 125 mg a.i./L.

Description of key information

ErC50 (72 h) > 51 mg a.i./L (nominal, OECD 201, freshwater, P. subcapitata); read-across

NOErC (72 h) ≥ 51 mg a.i./L (nominal, OECD 201, freshwater, P. subcapitata); read-across

 

EL50 (72 h) = 435 mg/L (nominal loading level WAF, ISO 10253, saltwater, S. costatum); read-across

NOELR (72 h) = 180 mg/L (nominal loading level WAF, ISO 10253, saltwater, S. costatum); read-across

Additional information

There is no study available, in which the toxicity of the target substance D-Glucopyranose, oligomeric, pentyl glycosides (CAS 100231-63-8) to aquatic algae was assessed. Therefore, read-across to the two structurally and chemically closely related source substances D-Glucopyranose, oligomeric, butyl glycoside (CAS 31387-97-0) and D-Glucopyranose, oligomers, hexyl glycosides (CAS 54549-24-5) was performed in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5 in order to meet the standard information requirements laid down in Annex VII of REACh Regulation (EC) No 1907/2006. Based on the high degree of physico-chemical similarity between the target and source substances, the selected source substances are considered suitable representatives for the assessment of the toxicity of the target substance to aquatic algae. A detailed read-across approach justification is provided in IUCLID section 13.

 

By means of the read-across approach, two key studies and one supporting study are available for the assessment of the toxicity of the target substance to aquatic algae. All the available studies complied with GLP.

For the source substance D-Glucopyranose, oligomeric, butyl glycoside (CAS 31387-97-0) one key study is available, in which the model organism P. subcapitata was exposed to nominal concentrations of 1, 10, and 100 mg/L of a 51% solution in a static test design for 72 h (Inst. Techn. FCBA, 2010). The study was performed according to OECD 201. The actual test item concentrations in the test vessels were analytically verified by TOC and resulted in 87.3 to 98.9% TOC recovery. After 72 h, no effects on algae growth were observed, resulting in a NOErC (72 h) of ≥ 100 mg/L (nominal) and an ErC50 (72 h) of > 100 mg/L (nominal), equivalent to > 51 mg a.i./L (the highest test concentration).

For the source substance D-Glucopyranose, oligomers, hexyl glycosides (CAS 54549-24-5) one freshwater study and one saltwater study are available. Neither study analytically verified the actual test item concentrations in the test vessels. The key study (Svalheim 2003) was performed in saltwater, equivalently or similarly to ISO 10253, using the model organism S. costatum and resulted in an EL50 (72 h) of 435 mg/L and a NOELR (72 h) of 180 mg/L (nominal loading rates of water accommodated fractions, WAF).

The freshwater (supporting) study was conducted according to OECD 201 using the model organism S. subspicatus and resulted in an ErC50 (72 h) of 780 mg a.i./L and a NOEC (72 h) of 125 mg a.i./L.

Thus, the available results taken together indicate no hazard to aquatic algae.

 

Based on the high degree of structural and physico-chemical similarity between the target and the selected source substances, the target substance is expected to exhibit a similar ecotoxicological profile as the source substances. Therefore, the target substance D-Glucopyranose, oligomeric, pentyl glycosides (CAS 100231-63-8) is not expected to cause toxic effects to aquatic algae.