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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
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:
data from handbook or collection of data
Justification for type of information:
Data is from peer reviewed journal
Qualifier:
according to
Guideline:
other: as mentioned above
Principles of method if other than guideline:
To evaluate toxicity of test chemical on marine macroalga, Ulva lactuca
GLP compliance:
not specified
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
other: Ulva lactuca
Details on test organisms:
- Source (laboratory, culture collection): Thalli of the green seaweed, Ulva lactuca, were collectedfrom the inter-tidal shore at Mount Baton
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): Prior to experimentation, thalli were maintained for 3 days in Perspex aquaria containing 5 l ofaerated, filtered , seawater (salinity = 33.8) in a temperature-controlled culture room set at 15°C (representative of local, summer seawater temperatures) under aphoton irradiance of on a 12:12 h light: dark photoperiod
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
pH:
7.9 and 8.2.
Nominal and measured concentrations:
0, 5, 10, 15, 20, 25, 30, 35 and 40 mg/l
Details on test conditions:
- Test vessel: glass beakers-fill volume: 100 m
l- Approximately 24 h prior to commencing the experiments, discs of 16 mm diameter were cutfrom the central portion of ca. 30 individual thalli using a plastic cork borer and left to recover from any resulting trauma. From thepooled discs, two or three were randomly selected and transferred to individual glass beakers containing100 ml of treatment solutions
- Salinity (for marine algae): 33.8- Light intensity and quality: 120 µ m-2/s
Reference substance (positive control):
not specified
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
30 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Validity criteria fulfilled:
not specified
Conclusions:
The 50% effect on biomass of marine microalgae was observed in the concentration 30 mg/l after 48 h exposure of tset chemical.
Executive summary:

An experiment was conducted to determine the toxicity of test chemical to aquatic algae. In this the test organisms used wasmarine microalgae Ulva lactuca. Before initiation of experiment the thalli were maintained for 3 days in Perspex aquaria containing 5 l of aerated, filtered , seawater (salinity = 33.8) in a temperature-controlled culture room set at 15° (representative of local, summer seawater temperatures) under a irradiance of on a 12:12 h light: dark photoperiod. Approximately 24 h prior to commencing the experiments, discs of 16 mm diameter were cut from the central portion of ca. 30 individual thalli using a plastic cork borer and left to recover from any resulting trauma. From the pooled discs, two or three were randomly selected and transferred to individual glass beakers containing 100 ml of treatment solutions.

The nominal concentration selected for the experiment were 0, 5, 10, 15, 20, 25, 30, 35 and 40 mg/l. Data were analysed by either Repeat Measure Analysis of Variance (ANOVA) using SPSS (v.15.0) or by one-way or two-way ANOVA using Minitab (v. 15). The Effect concentration at which 50% effect on biomass of marine microalgae was observed was 30 mg/l after 48 h.

Since the test chemical is readily biodegradable in nature test chemical is considered to be non toxic and cannot be classified as per CLP regulation.

Description of key information

An experiment was conducted to determine the toxicity of test chemical to aquatic algae. In this the test organisms used wasmarine microalgae Ulva lactuca. Before initiation of experiment the thalli were maintained for 3 days in Perspex aquaria containing 5 l of aerated, filtered , seawater (salinity = 33.8) in a temperature-controlled culture room set at 15° (representative of local, summer seawater temperatures) under a irradiance of on a 12:12 h light: dark photoperiod. Approximately 24 h prior to commencing the experiments, discs of 16 mm diameter were cut from the central portion of ca. 30 individual thalli using a plastic cork borer and left to recover from any resulting trauma. From the pooled discs, two or three were randomly selected and transferred to individual glass beakers containing 100 ml of treatment solutions.

The nominal concentration selected for the experiment were 0, 5, 10, 15, 20, 25, 30, 35 and 40 mg/l. Data were analysed by either Repeat Measure Analysis of Variance (ANOVA) using SPSS (v.15.0) or by one-way or two-way ANOVA using Minitab (v. 15). The Effect concentration at which 50% effect on biomass of marine microalgae was observed was 30 mg/l after 48 h.

Since the test chemical is readily biodegradable in nature test chemical is considered to be non toxic and cannot be classified as per CLP regulation.

Key value for chemical safety assessment

EC50 for freshwater algae:
30 mg/L

Additional information

Different studies have been conducted to determine the toxicity of test chemical to aquatic algae from different sources and their results are summarized below.                                                                                   

 

The first study was reviewed from the ECotoxiccology journal (2011) in this an experiment was conducted to determine the toxicity of test chemical to aquatic algae. In this the test organisms used was marine microalgae Ulva lactuca. Before initiation of experiment the thalli were maintained for 3 days in Perspex aquaria containing 5 l of aerated, filtered , seawater (salinity = 33.8) in a temperature-controlled culture room set at 15° (representative of local, summer seawater temperatures) under a irradiance of on a 12:12 h light: dark photoperiod. Approximately 24 h prior to commencing the experiments, discs of 16 mm diameter were cut from the central portion of ca. 30 individual thalli using a plastic cork borer and left to recover from any resulting trauma. From the pooled discs, two or three were randomly selected and transferred to individual glass beakers containing 100 ml of treatment solutions.

The nominal concentration selected for the experiment were 0, 5, 10, 15, 20, 25, 30, 35 and 40 mg/l. Data were analysed by either Repeat Measure Analysis of Variance (ANOVA) using SPSS (v.15.0) or by one-way or two-way ANOVA using Minitab (v. 15). The Effect concentration at which 50% effect on biomass of marine microalgae was observed was 30 mg/l after 48 h.

 

In another study an experiment was conducted to determine the toxicity of test chemical to aquatic algae according to the OECD Guideline 201 (Alga, Growth Inhibition Test). In this experiment test organism used was Scenedesmus subspicatus. The nominal concentration sof test chemical used were 0 (control), 0.32, 1.0, 3.2, 10, 32, and 100 mg/l. The experiment was conduceted in ststic condition for 72 h at temperature 23 ± 2 °C. Four replicate test flasks were run at each treatment level. Tests were run under continuous lighting of 35 – 70 μE/m2*s. Endpoints were determined for algal growth rate and algal cell density. The EC0, EC10, and EC50 were calculated for rate and cell density. The effect concentrations of biomass and growth rate on green algae after 72 h was observed to be 30 mg/l and 48 mg/l respectively.

 

Next study was reviewed from secondary source in this an experiment was conducted to determine the toxicity of test chemical to aquatic algae according to the DIN 38412, Part 9. In this experiment test organism used was Scenedesmus subspicatus -Strain: SAG 8681.The nominal concentration of test chemical used in this were 0 (control), 0.01, 0.03, 0.1, 0.3, 1.0, 3.0 and 10 mg/L. Each experimental group was replicated three times. Test vessels were 300-ml Erlenmeyer flasks holding 100 ml of test solution. At the beginning of the test, flasks were inoculated with 1.0 ml of algal cell inoculum to achieve a concentration in each flask of 1 × 10E4 cells/ml. Flasks were placed under continuous lighting of 2000 lux and continuously shaken at 120 rpm by means of an orbital shaker. At 24, 48, 72 and 96 hours, a sample from each flask was taken and the density of algal cells in the sample (cells/ml) was measured using an electronic particle counter (Coulter-Counter). Cell densities were converted to growth rates and growth rates were used in the calculation of EC values.

The EC50 Value of test chemical was determined to be 1.84 mg/L after exposure of test chemical for 96 h.

 

By considering results of all the studies mentioned above the EC50 value was determined to be in range 1.84 mg/L to 48 mg/l. Since the test chemical is readily biodegradable in nature test chemical is considered to be non toxic and cannot be classified as per CLP regulation.