Manganese oxalate

Endpoint summary

Additional information

The acute toxicity of the test item Manganese oxalate dihydrate to zebra fish (Brachydanio rerio) was determined in a 96-hour semi-static test with daily test medium renewal according to the EU Commission Directive 92/69/, Part C.1, the Commission Regulation (EC) No 440/2008, Part C.1 and the OECD Guideline for Testing of Chemicals No. 203 (1992).

A limit test was performed in accordance with the threshold approach requiring that the fish test be performed with a single concentration close to or slightly higher than the lowest EC₅₀value obtained in tests with algae and daphnia. The threshold approach(based on the Guidance on Information Requirements and Chemical Safety Assessment, ECHA (2008)) was used to demonstrate, that zebra fish is not the most sensitive species for Manganese oxalate dihydrate. 

Due to the low solubility of the test item in the EPA medium, a dispersion of the test item with the loading rate of 100 mg/L was continuously stirred at room temperature over 15 minutes. Pre-experiments (non-GLP) according the solubility of the test item as well as the tests conducted with algae and daphnia prior to this fish study showed that an equilibrium was reached after that time of stirring. Then, the dispersion was filtered. The undiluted filtrate with the maximum concentration of dissolved test item was used as the test medium.Additionally, a control was tested in parallel.

 

The preparation of the test medium was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2000. In the analyzed test medium samples from the start of all test medium renewal periods, analytically determined concentration of Manganese oxalate dihydrate (based on manganese) were in the range of 69 - 80 mg/L. At the end of the test medium renewal periods, the measured test item concentration was in the range of 70 - 85 mg/L. Thus, the active ingredient manganese was stable in the test medium over the test renewal periods of 24 hours. The mean measured concentration (calculated as the average over all measurements) was 75 mg/L.

The biological results were related to the mean measured concentration and the corresponding loading rate of the test item of 100 mg/L.

In the control and at the mean measured concentration of 75 mg/L (loading rate of 100 mg/L), no mortality or other visible abnormalities were determined during the test period of 96 hours. Related to Manganese oxalate, which is the substance for registration (correction factor: 1.252, adjusted to the anhydrous form of the substance), no effects were found at the mean measured concentration of 59.9 mg/L.

 

The biological test results (based on the mean measured concentration and loading rate of the test item) were as follows:

 

	Loading rate (mg/L)	Mean measured concentration (mg/L)
– 96-hour LC50:	>100	>75
– 96-hour LC0:	>=100	>=75
– 96-hour LC100:	>100	>75
– 96-hour NOEC:	>=100	>=75
– 96-hour LOEC:	>100	>75

 

 

The biological test results forManaganese oxalatewere as follows:

 

	Mean measured concentration (mg/L)
– 96-hour LC50:	>59.9
– 96-hour LC0:	>=59.9
– 96-hour LC100:	>59.9
– 96-hour NOEC:	>=59.9
– 96-hour LOEC:	>59.9

 

 

 

The acute toxicity of the test item Manganese oxalate dihydrate toDaphnia magnawas determined in a 48‑hour semi-static test according to the EU Commission Directive 92/69/EEC, Part C.2, the Commission Regulation (EC) No. 440/2008, Part C.2 and the OECD Guideline for Testing of Chemicals, No. 202 (2004).

Due to visible reaction product after addition of the test item to the test water, a dispersion of the test item with the loading rate of 100 mg/L was continuously stirred at room temperature over 3 hours. Then, the dispersion was filtered. The undiluted filtrate with the loading rate of 100 mg/L and dilutions 1:2, 1:4, 1:8 and1:16of the undiluted filtrate with the loading rate of 100 mg/L were used as test media. Additionally, a control was tested in parallel.

The preparation of the test media was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2000.

 

At the start of the test medium renewal periods, the analytically determined concentrations of Manganese oxalate dihydrate (based on manganese) in the test media (dilutions 1:4, 1:2 and the undiluted filtrate) ranged between 86 and 91% of the nominal values. Thus, the correct dosing of the test item was confirmed. At the end of the test medium renewal periods, 87 to 92% of the nominal concentrations (based on manganese) were found.

The biological test results of the test item (based on mean measured concentrations) were as follows:

 

– 48-hour EC50:	>90	mg/L
– 48-hour EC0	22	mg/L
– 48-hour EC100:	>90	mg/L
The biological test results related toManganese oxalate(correction factor: 1.252 and based on mean measured concentrations) were as follows:
– 48-hour EC50:	>      71.9	mg/L
– 48-hour EC0	17.6	mg/L
– 48-hour EC100:	>      71.9	mg/L

 

 

 

 

The influence of the test item Manganese oxalate dihydrate on the growth of the freshwater green algal speciesPseudokirchneriella subcapitatawas investigated in a 72 ‑hour static test according to the OECD Guideline 201 (2006), C.3 (1992) and the Commission Regulation (EC) No 761/2009, C.3.

The nominal concentrations of the test item of 1.0, 3.2, 10, 32 and 100 mg/L were tested in parallel with a control. The measured concentrations of Manganese oxalate dihydrate (based on manganese) in the test media of the test concentrations of 3.2 to 100 mg/L were between 97 and 110% of the nominal values at the start of the test and between 94 and 102% at the end of the test.  

Thus, the correct dosing of the test item Manganese oxalate dihydrate was confirmed, and the biological results (based on the nominal concentrations of the test item) were as follows:

 

Parameter	Growth rate	Yield
(0-72 h)
EC50  (mg/L)	86	29
95% confidence interval	80-93	23-38
EC20  (mg/L)	41	12
95% confidence interval	35-46	7.2-16
EC10  (mg/L)	28	7.3
95% confidence interval	23-33	3.7-11
NOEC (mg/L)	3.2	3.2
LOEC (mg/L)	10	10

The biological test results related toManganese oxalate(correction factor: 1.252 and based on mean measured concentrations) were as follows:

LOEC 72h (growth rate and yield):  7.98 mg/L

NOEC 72h (growth rate and yield):  2.39 mg/L

EC50 72h (growth rate):  68.7 mg/L

 

 

 

The inhibitory effect of the test item Manganese oxalate, dihydrate on the respiration rate of aerobic wastewater micro-organisms of activated sludge was investigated in a 3‑hour respiration inhibition test according to the OECD Guideline for Testing of Chemicals, No. 209, adopted 2010. Based on the results of the range-finding test and in agreement with the Sponsor a definitive test with the following nominal test item concentrations was performed: 38.4, 96, 240, 600 and 1500 mg/L with three replicates per concentration.

 The inhibition of the respiration rates for all tested concentrations was -5% at 38.4 mg/L, 8% at 96 mg/L, 19% at 240 mg/L, 47% at 600mg/L and 45% at 1500 mg/L compared to the control.

 

The following EC_X-values and their 95% confidence limits were calculated:

 

EC10	90	mg/L
95% confidence limits:	n.d. – 284	mg/L
EC20:	228	mg/L
95% confidence limits:	0 – 574	mg/L
EC50:	1356	mg/L
95% confidence limits:	537 – n.d.	mg/L
EC80:	>1500	mg/L

 

Where n.d. represents value not determined due to mathematical reasons.

 

The definitive test, with five test concentrations and three replicates for each, was designed to primarily determine the ECx-values.Nevertheless, the following3-hours NOEC was derived:

 

NOEC

96

mg/L

 

The biological test results related toManganese oxalate(correction factor: 1.252 and based on mean measured concentrations) were as follows:

EC 10:  71.9 mg/l

EC20:   182.1 mg/l

EC50:  1083.6 mg/L