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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report date:
1997

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes

Test material

Constituent 1
Reference substance name:
.beta.-Cyclodextrin, 2-hydroxypropyl cycloheptaamylose
IUPAC Name:
.beta.-Cyclodextrin, 2-hydroxypropyl cycloheptaamylose
Constituent 2
Chemical structure
Reference substance name:
-
EC Number:
420-920-1
EC Name:
-
Cas Number:
128446-35-5
Molecular formula:
Hill formula: (C42H70-nO35)(C3H7O)n; n(mittel)=5,25
IUPAC Name:
2-Hydroxypropyl-.beta.-cyclodextrine ethers
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material (as cited in study report): hydroxypropylated .beta.-cyclodextrin
- Physical state: white solid powder
- Analytical purity: 89.16%
- Storage condition of test material: room temperature

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Source: Department of Botany, Culture Collection of Algae, The University of Texas at Austin, Austin, Texas,
- Age of inoculum (at test initiation): 3 days

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
96 h

Test conditions

Hardness:
no data
Test temperature:
24-25°C
pH:
7.5-9.9
Dissolved oxygen:
no data
Salinity:
no data
Nominal and measured concentrations:
Measured concentrations: 0, 72, and 96 hour were 1248, 1115, and 1096 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Erlenmeyer flask
- Material, size, headspace, fill volume: 250ml
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 4

OTHER TEST CONDITIONS
- Light intensity and quality:8600 ± 10% lux
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 1 182 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
> 1 153 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 1 182 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
other: area under growth curve
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
< 1 153 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
other: area under growth curve
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 1 182 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 1 153 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
Based on the results of preliminary test, a single nominal test concentration of 1000 mg/L hydroxypropylated .beta.-cyclodextrin was selected for the definitive test. The definitive test with was conducted June 2, 1997, to June 6, 1997. Samples for analytical confirmation were collected at 0, 72, and 96 hours. The measured concentration at test initiation (0 hour) was 1248 mg/L for the 1000 mg/L nominal test concentration, which represents 125% of the nominal test concentration. At 72 hours, the measured concentration was 1115 mg/L for the 1000 mg/L nominal test concentration, which represents 112% of the nominal test concentration. The measured concentration at test termination (96 hours) was 1096 mg/L for the 1000 mg/L nominal test concentration, which represents 110% of the nominal test concentration. The 0- to 72-hour mean measured concentration was 1182 mg/L. The 0- to 96-hour mean measured concentration was 1153 mg/L. Quality control fortifications' were prepared using algal media without algae (abiotic) at a nominal concentration of 991, 976, and 1020 mg/L at 0, 72, and 96 hours, respectively. In addition to the abiotic quality control fortifications, the nominal concentrations of 946 and 947 were prepared at 72 and 96 hours, respectively, using algal media with algae (biotic). Recoveries ranged from 106 to 123% and averaged 110 ±7.3% of nominal. The 72- and 96-hour 1000 mg/L abiotic solutions were measured to be 1153 and 1129 mg/L, respectively, which represents 115 and 113%, respectively, of the 1000 mg/L nominal concentration. Based on analytical recoveries, hydroxypropylated .beta.-cyclodextrin appeared to be stable in the exposure system. All results were based on both the 0- to 72-hour mean measured concentration and 0- to 96-hour mean measured concentration.
Cell counts were conducted at 24, 48, 72, and 96 hours for each A, B, and C replicate of the control and 1000 mg/L test concentration. Initial cell counts at 0 hour were performed only on the control replicates. Logarithmic phase growth was confirmed at 96 hours with a mean cell count of 2.2 x 106 cells/mL in the control which was a 200-fold increase from the initial mean cell density of 1.1 x 104 cells/mL. The growth data were subjected to an ANOVA and multiple means test (Dunnett's test). The multiple means test did not show a significant inhibition effect (p =< 0.05) for the 1000 mg/L nominal concentration based on the growth rate parameter, as compared to the control after 96 hours of exposure. However, a significant inhibition effect (p =< 0.05) based on the area under the growth curve parameter was shown for the 1000 mg/L nominal concentration, as compared to the control after 96 hours of exposure.
The 0-24-, 0-48-, 0-72-, and 0-96-hour ErC50 values hydroxypropylated .beta.-cyclodextrin were >1182 mg/L (0- to 72-hour mean measured concentration), and the 0-96-hour EbC50 was > 1153 mg/L (0 to 96-hour mean measured concentration. Based on the absence of a growth inhibition effect for the area under the growth curve parameter, the 72-hour no-observed effect concentration was shown to be ~ 1182 mg/L (0- to 72-hour mean measured concentration) and the 96-hour no-observed effect concentration was shown to be <1153nig/L (0- to 96-hour mean measured concentration).
The 0-24-, 0-48-, 0-72-, and 0-96-hour ErC50 values for hydroxypropylated .beta.-cyclodextrin were > 1182 mg/L (0- to 72-hour mean measured concentration), and the 0-96-hour ErC50 was > 1153 mg/L (0- to 96-hour mean measured concentration. Based on the absence of a growth inhibition effect for the growth rate parameter, the 72-hour no-observed effect concentration was shown to be >= 1182 mg/L (0- to 72-hour mean measured concentration) and the 96-hour no-observed effect concentration was shown to be >= 1153 mg/L (0- to 96-hour mean measured concentration).
At 0, 72, and 96 hours, temperature and pH were measured in the control and 1000 mg/L nominal test solution. Measurements at 0 hour were taken from the parent solutions of the control and 1000 mg/L test concentration. Measurements at 72 and 96 hours were taken from replicates D and C, respectively of the control and 1000 mg/L test concentration. The temperature of the solutions ranged from 24 to 25°C and the pH values ranged from 7.5 to 9.9. The pH of the control and 1000 mg/L test solution at 72 and 96 hours had deviated more than 1 pH unit. The pH variability of more than 1 pH unit was apparently due to the cell biomass present at 72 and 96 hours.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The nominal test concentration of hydroxypropylated .beta.-cyclodextrin tested for this study was 1000 mg/L. Measured concentrations at 0, 72, and 96 hour were 1248, 1115, and 1096 mg/L, respectively. The 0- to 72-hour mean measured concentration was 1182 mg/L. The 0- to 96-hour mean measured concentration was 1153 mg/L. All results were based on both the 0- to 72-hour and 0- to 96-hour mean measured concentrations.
Using 0- to 72-hour mean measured concentration, the 24-, 48-, 72-hour EbC50 and ErC50 values for hydroxypropylated .beta.-cyclodextrin were > 1182 mg/L, respectively. Using 0- to 96-hour mean measured concentration, the 96-hour EbC50 and ErC50 values for hydroxypropylated .beta.-cyclodextrin were > 1153 mg/L, respectively. Based on the area under the growth curve parameter, the 72- and 96-hour no-observed effect concentrations were estimated to be > 1182 mg/L (0- to 72-hour mean measured concentration) and < 1153 mg/L (0- to 96-hour mean measured concentration), respectively. Based on the growth rate parameter, the 72- and 96-hour no-observed effect concentrations were estimated to be > 1182 mg/L (0- to 72-hour mean measured concentration) and ~ 1153 mg/L (0- to 96-hour mean measured concentration), respectively.
Executive summary:

The test article, hydroxypropylated .beta.-cyclodextrin , was tested in Selenastrum capricornutum according to OECD Guideline 201.

The primary objective of this test was to evaluate the inhibition or enhancement effect of hydroxypropylated .beta.- cyclodextr into Selenastrum capriconutum Printz under static conditions following the procedures outlined in ABC Protocol No. OECD 201. The test was designed to yield EC50 (EbC50 and/or ErC50) values following 24, 48, 72, and 96 hours of exposure and a 96-hour no-observed effect concentration (NOEC).The definitive study was conducted from June 2, 1997, to June 6, 1997.

The 96-hour acute toxicity test was conducted by exposing Selenastrum capriconutum Printz to the single nominal exposure concentration of 1000 mg/L hydroxypropylated .beta.-cyclodextrin, along with a control. The test was conducted in 250-mL Erlenmeyer flasks containing 100 mL of the test solution. There were four control replicates (A, B, C, and D) of the control solution and six replicates (A, B, C, D, E, and F) of the 1000 mg/L test solution. Each A, B, C, and D replicate received 1.0 mL of algal inoculum containing approximately 1.0 x 106 cells/mL, resulting in approximately 1.0 x 104 cells/mL for each flask. The D replicates were used only for water quality measurements and collection of analytical samples at 72 hours. The1000 mg/L replicates E and F were· used as the abiotic (no algae present) replicates and were used for collection of 72- and 96-hour analytical samples.

Water quality parameters of temperature and pH were measured at 0, 72, and 96 hours of the study. The temperature of the test solutions ranged from 24 to 25°C. The pH values of the test solutions ranged from 7.5 to 9.9.

Samples of the control and 1000 mg/L test solutions were collected at test initiation (0 hour), 72 hours, and at test termination (96 hours) for analytical confirmation. The measured concentration at test initiation (0 hour) was 1248 mg/L for the 1000 mg/L nominal test concentration, which represents 125% of the nominal test concentration. At 72 hours, the measured concentration was 1115 mg/L for the 1000 mg/L nominal test concentration, which represents 112% of the nominal test concentration. The measured concentration at test termination (96 hours) was 1096 mg/L for the 1000mg/Lnominal test concentration, which represents 110% of the nominal test concentration. The 0- to 72-hour mean measured concentration was 1182mg/L.The 0- to 96-hour mean measured concentration was 1153 mg/L.

The 72- and 96-hour 1000 mg/L abiotic solutions were measured to be 1153 and 1129 mg/L, respectively, which represents 115 and 113 %, respectively, of the 1000 mg/L nominal concentration. All results were based on both the 0- to 72-hour mean measured concentration and 0- to 96-hour mean measured concentration.

Using the 0- to 72-hour mean measured concentration, the 24-, 48-, 72-hour EbC50 and ErC50 values for hydroxypropylated .beta.-cyclodextrinwere estimated to be > 1182mg/L.Using the 0- to 96-hour mean measured concentration, the 96-hour EbC50 and ErC50 values forhydroxypropylated .beta.-cyclodextrinwere estimated to be > 1153 mg/L. Based on the area under the growth curve parameter, the 72- and 96-hour no-observed effect concentrations were estimated to be >= 1182 mg/L (0- to 72-hour mean measured concentration) and < 1153 mg/L (0- to 96-hour mean measured concentration) respectively. Based on the growth rate parameter, the 72- and 96-hour no-observed effect concentrations were estimated to be > 1182 mg/L (0- to 72-hour mean measured concentration) and > 1153 mg/L (0- to 96-hour mean measured concentration), respectively.