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short-term toxicity to fish

In a pre-guideline study (modified routine bioassay method, company guideline) Oncorhynchus mykiss were exposed in a 48 h test to aqueous test media containing the test item at various concentrations. A dose response study with 100, 200, 500 and 1000 mg/L test item – was performed. LC50 was determinied by plot on semi logarithmic scale showing the relation between the test item concentration in the test media and the percentage of surviving animals. At a dose level of 500 mg/L 80 % of the animals survived and at a dose level of 1000 mg/L no animal survived. All animals survived at dose level 200 mg/L. The following dose descriptors were determined:

LC50 (48 h) = 650 mg/L (nominal)

LC0 (48 h) = 200 mg/L (nominal)

LC100 (48 h) = 1000 mg/L (nominal)

tests according to OECD guidelines 201 and 202 were performed with a dose level of 177 mg/L test material, refering to 100 mg/l trisodium trioxalatoferrate contained in the test material.

Different analytical methods for the determination of the trisodium trioxalatoferrate concentration in the test media were investigated, e.g. standard iron cuvette test or UV absorption of iron oxalate complex. No reliable and reproducible method could be established. Therefore, no analytical monitoring was performed and all effect values given are based on the nominal test item concentrations.

short-term toxicity to aquatic invertebrates

The toxic effect of the test item to Daphnia magna was assessed in a 48 h static test according to OECD guideline 202. A limit test with 177 mg/L test item was performed. 20 daphnids, divided into 4 replicates, each with 5 daphnids, and replicates were used for the test solution and the control. The mobility of the Daphnia was determined by visual observation after 24 and 48 hours.

Based on the test results the following dose descriptors were laid down:

EC100 (48 h) > 177 mg/L

EC50 (48 h) > 177 mg/L

EC10 (48 h) > 177 mg/L

toxicity to aquatic algae and cyanobacteria

The inhibitory effect of the test item on the growth of freshwater algae was determined according to OECD guideline 201. Cultures of Desmodesmus subspicatus were exposed in a static test to the test item concentrations in a geometrical series with a dilution factor of 2.5: 177, 70.8, 28.3, 11.3 and 4.53 mg/L. The inhibition of growth in relation to control cultures was determined over a test period of 72 hours.

This study encompassed 6 treatment groups (5 dose rates of the test item and a control) with three replicates per test concentration and 6 replicates for the control. Beside other parameters growth rates were determined. The following results were reported:

 

EC50 (72 h) > 177 mg/L

EC20 (72 h) = 117 mg/L

EC10 (72 h) = 98.4 mg/L

NOEC (72 h) = 70.8 mg/L

LOEC (72 h) = 177 mg/L

toxicity to microorganisms

A Respiration Inhibition Test with activated sludge according to OECD guideline 209 was performed with the test item. The test was carried out for a period of 3 hours under static conditions with the nominal concentrations of 10 and 100 mg/L. No inhibition was observed with the tested concentrations. Therefore, the test item had no toxic effects on respiration activity of activated sludge: NOEC > 100 mg/L.

At a concentration of the reference substance of 10 mg/L, the respiration rate was inhibited by 47.6 %. The EC50-value for 3,5-dichlorophenol was found to be about 10.2 mg/L. Almost complete inhibition (94.5 %) was observed at 50 mg/L confirming the activity of the test system.

Additional information