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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The results show that for Pseudokirchneriella subcapitata EbC50 (based on biomass) and ErC50 (based on growth rate) are higher than 113.7 mg/L (based on initial measured concentration at T0). Selenastrum capricornutum 96h EC50 = 23 mg/L, 96h NOEC = 14 mg/L (based on cell number) (EPA OPPTS 850.5400, GLP, analytical monitoring).

Key value for chemical safety assessment

EC50/LC50 for freshwater algae:
113.7 mg/L

Additional information

The determination of the growth inhibition of the fresh algae Pseudokirchneriella subcapitata exposed to dimethyl sulphide for a duration of 72h was performed following the method OECD 201 and according to GLP. Algae were exposed to the following concentrations for 72h: 0, <LOQ, 4.51, 11.34, 21.94, 47.74, 113.72 mg/L (Initial measured concentrations). The study was performed using an algal suspension so that the initial cell concentration was equal to 1x10E4 cells/mL. The algal concentration was measured daily. Analytical chemistry (GC-FID) and physical-chemical measurement (pH and O2 concentration) were carried out at the beginning and the end of the test. The validity criteria of the study were respected: the increase in cell density (R), measured in the control solution between the end and the beginning of the test, was greater than a factor of 16 (R = 130) ; the final concentration of dimethyl sulphide were maintained within the designated limit of 80% of the initial concentrations in non inoculated flasks.

This is supported by Drottar (1999). In a 96 hour acute toxicity study, the cultures of Selenastrum capricornutum were exposed to dimethyl sulphide (under static conditions in accordance with the testing guideline OPPTS Number 850-5400 and with GLP.The 96-hr EC50 was 23 mg dimethyl sulphide/L. The 96-hr NOEC was 14 mg dimethyl sulphide/L.  The % cell density inhibition in the treated algal culture as compared to the control ranged from -5.6% to 82%. Some enlarged cells were observed in the 58 mg/L treatment group.