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Toxicity to aquatic algae and cyanobacteria

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Description of key information

The ErC50 and EyC50 of FAT 36038/J TE observed for test period of 72-hour for freshwater alga (Pseudokirchneriella subcapitata) were 0.16 and 0.29 mg/L, respectively.

However, FAT 36038/J is a violet colored dye, which can lead to intense discoloration of the test medium during the testing. The discoloration of test medium in algal tests leads to decreasing the amount of light reaching the algae, thereby hampering the photosynthesis process and adversely affecting the algal growth. In the present study, no consideration was given to this point, and hence the study was considered to be lacking on this front and disregarded. Instead a study investigating toxicity to aquatic plants was conduced and taken for consideration.

Key value for chemical safety assessment

Additional information

A key study was performed to determine growth Inhibition in Freshwater green Algae (Pseudokirchneriella subcapitata) in accordance with OECD-201 guideline with FAT 36038/J TE. The test concentrations were selected as 0.0008, 0.003, 0.008, 0.03, 0.09, 0.28 and 0.88 mg/L.

At the end of 72 hr exposure time the following results were observed:

Average Specific Growth Rate:

The percent inhibition on the average growth rate at the end of 72 hour was 0.17 %, 11.36 %, 11.77 %, 26.96 %, 51.63 %, 56.31 and 68.14 % in test concentration of 0.0008, 0.003, 0.008, 0.03, 0.09, 0.28 and 0.88 mg/L respectively.

From the average specific growth rate recorded with the different test concentrations viz.,0.0008, 0.003, 0.008, 0.03, 0.09, 0.28 and 0.88 mg/L the concentration that inhibited 50% growth (ErC50) of Freshwater green Algae (Pseudokirchneriella subcapitata) was calculated as 0.16 mg/L.

The no observed effect concentration (NOEC) and the lowest observed effect concentration (LOEC) were recorded to be 0.0008 mg/L and 0.003 mg/L respectively.

Yield:

The percent inhibition on the yield at the end of 72 hour was 0.04 %, 5.20 %, 6.15 %, 20.32 % 31.16 %, 43.23 and 70.79 % in test concentrations 0.0008, 0.003, 0.008, 0.03, 0.09, 0.28 and 0.88 mg/L respectively.

From the yield recorded with the different test concentrations viz.,0.0008, 0.003, 0.008, 0.03, 0.09, 0.28 and 0.88 mg/L, the concentration that inhibited 50 % growth (EyC50) of Freshwater green Algae (Pseudokirchneriella subcapitata) was calculated as 0.29 mg/L.

The no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) were calculated as 0.0008 mg/L and 0.003 mg/L respectively.

The ErC50 and EyC50 of FAT 36038/J TE observed for test period of 72-hour for freshwater alga (Pseudokirchneriella subcapitata) were 0.16 and 0.29 mg/L, respectively.

However, FAT 36038/J is a violet colored dye, which can lead to intense discoloration of the test medium during the testing. The discoloration of test medium in algal tests leads to decreasing the amount of light reaching the algae, thereby hampering the photosynthesis process and adversely affecting the algal growth. In the present study, no consideration was given to this point, and hence the study was considered to be lacking on this front and disregarded. Instead a study investigating toxicity to aquatic plants was conduced and taken for consideration.