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Ecotoxicological information

Long-term toxicity to aquatic invertebrates

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Description of key information

NOEC = 10%v/v saturated solution (0.0738  mg/L mean measured concentration of test material in test media based on day 0 and day 2 analyses of the 100% v/v solution), OECD 211, EPA OPPTS 850.1300, Priestly & Mullee (2010)

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater invertebrates:
74 µg/L

Additional information

The effect of the test material on the survival and reproduction of Ceriodaphnia dubia over an 8 -day period was investigated in a study which was conducted under GLP conditions and partly in accordance with the standardised guidelines OECD 211 and EPA OPPTS 850.1300.

As the test material is considered to be poorly soluble in water saturated solutions of test material were prepared for use in the study.

Based an acute toxicity to Daphnia magna study (Harlan Laboratories Ltd Project Number: 2702/0181), Ceriodaphnia dubia were exposed (10 replicates of a single daphnid per group) to an aqueous solution of the test material over a range of test concentrations of 10, 32 and 100% v/v saturated solution for a period of 8 days. The test material was prepared by stirring an excess of the test material in reconstituted water (Elendt M4) water using a magnetic stirrer at approximately 100 rpm at a temperature of approximately 25°C for 48 hours. After stirring, any undissolved test material was removed by filtration through a pre-conditioned 0.2 µm filter to produce the 100% v/v saturated solution. A series of dilutions was made from this saturated solution to prepare the remainder of the test series. The test solutions were renewed 3 times. The numbers of live and dead adult Ceriodaphnia and young daphnids (live and dead) were determined daily. The Ceriodaphnia were fed daily with an algal suspension and YAT (yeast, alfalfa, trout chow) combination.

The test material contains a theoretical manganese content of 63% w/w. The test samples were analysed for manganese only. Analysis of the test preparations on days 0, 2, 5, 7 and 8 showed measured concentrations of manganese to be less than the limit of quantitation (LOQ) of the analytical method (assessed as 0.050 mg/L) with the exception of the 32% and 100% v/v saturated solution on Days 0 (fresh media) and 2 (old media). Analysis of these samples showed measured concentrations as test material of 0.233 and 0.810 on day 0 and 0.138 and 0.666 mg/L on day 2. Given that the majority of the analyses were less than the LOQ, it was considered justifiable to base the results on the nominal test concentrations only.

The 8-Day EC50 (immobilisation) value, based on nominal test concentrations, for the parental Ceriodaphnia generation (P1) was greater than 100% v/v saturated solution.The 8-Day EC50 (reproduction) based on nominal test concentrations was 32% v/v saturated solution with 95% confidence limits of 20 - 50% v/v saturated solution.The "Lowest Observed Effect Concentration" (LOEC) and the "No Observed Effect Concentration" (NOEC) based on nominal test concentrations were 32% and 10% v/v saturated solution respectively.