OligoActiv EDDHA-Mn

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to Read Across Statement attached in Section 13

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

450 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

No further details are available.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: up to 80 % inhibition occurred

Reported statistics and error estimates:

In order to calculate the inhibition effects of the test item at a particular concentration, the respiration rate was expressed as percentage of the mean of the 2 control respiration rates.
The degree of inhibition (EC10 and EC20) of the test item was evaluated by Probit analysis according to Finney. The values were given with an accuracy of 2 significant digits.
The degree of inhibition (EC20; EC50 and EC80) of the reference item was also evaluated by Probit analysis according to Finney.

Measured data of oxygen content of the test assays at the begin and end of the evaluation time:

Assay identification	BC1	BC2	RS1	RS2	RS3	TS1	TS2	TS3	TS4	TS5
O2-concencentration Start [mg/L]	8.0	8.0	8.4	8.7	9.1	8.2	8.3	8.5	7.8	7.6
O2 -concentration after 6 minutes [mg/L]	7.0	7.0	7.5	8.2	8.9	7.5	7.5	7.5	6.5	6.0
O2consumption rate [mg/L in 6 min]	1.0	1.0	0.9	0.5	0.2	0.7	0.8	1.0	1.3	1.6
O2-consumption rate [mg/Lxh]	10	10	9	5	2	7	8	10	13	16
Specific O2-consumption rate [mg O2/gxh]	7	7	6	3	1	5	5	7	9	11
RS/TSconcentrations[mg/L]	-		1	10	100	1000	500	250	125	62.4
Calculation of inhibition respiration[%]	-	-	10	50	80	30	20	0	-30	-60

Legend: TS = test item, RS = reference item, BC = blank control

Validity criteria fulfilled:

yes

Remarks:

Validity criteria of the applied guideline were fulfilled.

Conclusions:

The study is regarded as a valid guideline study conducted under certificated GLP compliance. According to the reported EC50 value (> 1000 mg/L, nominal) the test substance is not acutely toxic towards aquatic microorganisms. The same result is expected for the organic constituents of target substance since it has the same composition as the source substance.

Executive summary:

The toxicity of Acetic acid, oxo-, sodium salt, reaction products with ethylenediamine and phenol, iron sodium salts (CAS 84539-55-9) towards freshwater microorganisms was investigated in accordance to OECD Guideline 209 / EU Method C11. Activated sludge was collected from the aeration tank at a municipal wastewater treatment. Aliquots of the stock solutions with test- or reference substance were pipetted into test vessels and made up with demineralized water to a volume of 150 mL. After that 8 mL synthetic medium were given to the test vessel. To prepare the blank control assays 150 mL of demineralized water and 8 mL synthetic medium were given to the blank control test vessels. The pH-values were measured in all test vessels. An adjustment was not necessary. 42 mL demineralized water were added to each test vessel. After addition of 50 mL of the inoculum suspension (dry weight 7.5 g/L) the incubation was started by aeration of the test vessels with pressure air. The vessels for the blank control assays were prepared according to the same procedure without addition of test- or reference item. After 180 minutes incubation the mixtures in the test vessels were placed subsequently into a closed oxygen measuring cell. As a result, an EC50(3h) and EC80(3h) > 1000 mg/L and an EC10(3h): 450 mg/L is reported.

Reference 2

Endpoint:

toxicity to microorganisms, other

Remarks:

non-specific esterase activity, proliferation rate inhibition

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to Read Across Statement attached in Section 13

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

9 h

Dose descriptor:

IC50

Effect conc.:

2 800 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

growth inhibition

Duration:

1 h

Dose descriptor:

EC50

Effect conc.:

359.33 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

other: non-specific esterase activity

Calculation of the EC50 for the target substance:

concentration of manganese in the target substance: 7.5 %

EC50(1h) for manganese = 26.95 mg/L

 

EC50(1h) for the target substance = 26.95 mg/L/0.075 = 359.33 mg/L.

 

IC50(9h) for manganese = 210 mg/L

 

IC50(9h) for the target substance = 210 mg/L/0.075 = 2800 mg/L.

Conclusions:

The reported EC50(1h) and the IC50(9h) correspond to values of 359.33 mg/L and 2800 mg/L for the target substance.

Executive summary:

The data on manganese sulfate allows estimating corresponding EC50 and IC50 for the target substance. The reported EC50(1h) and the IC50(9h) correspond to values of 359.33 mg/L and 2800 mg/L for the target substance.

Reference 3

Endpoint:

toxicity to microorganisms, other

Remarks:

mortality of the rotifer L. inermis (isolated from activated sludge) after 24 h exposure to MnCl2

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to Read Across Statement attached in Section 13

Reason / purpose for cross-reference:

read-across source

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

25.59 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to the target substance

Basis for effect:

other: mortality

Calculation of the EC50 for the target substance:

concentration of manganese in the target substance: 7.5 %

EC50(24h) for manganese = 1.92 mg/L

EC50(24h) for the target substance = 1.92 mg/L/0.075 = 25.59 mg/L

Validity criteria fulfilled:

not specified

Conclusions:

The EC50 value for elemental Mn (2 +) was determined to be 1.92 mg/L. This corresponds to an EC50 value of 25.59 mg/L for the target substance.

Executive summary:

The aim of the study was to assess the toxicity of a range of trace metals to the rotifer Lecane inermis, a species tested as a potential biological tool to control activated sludge bulking caused by overgrowth of filamentous bacteria in wastewater treatment plants. LC50 values (concentration lethal to 50 % of individuals, mg/L) were ranked in the following order: Cu<Al<Fe<Zn<Sn<Mn. The EC50 value for elemental Mn (2 +) was determined to be 1.92 mg/L. This corresponds to an EC50 value of 25.59 mg/L for the target substance.

Reference 4

Endpoint:

toxicity to microorganisms, other

Remarks:

mortality and malformations in Spirostomum ambiguum

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to Read Across Statement attached in Section 13

Reason / purpose for cross-reference:

read-across source

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

1 237.33 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

other: morphology

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

1 973.33 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

other: mortality

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1 453.33 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

other: morphology

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1 946.67 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

other: mortality

Calculation of the EC50 for the target substance:

concentration of manganese in the target substance: 7.5 %

morphology

EC50(24h) for manganese = 92.8 mg/L

EC50(24h) for the target substance = 92.8 mg/L/0.075 = 1237.33 mg/L

EC50(48h) for manganese = 109 mg/L

EC50(48h) for the target substance = 109 mg/L/0.075 = 1453.33 mg/L

mortality

EC50(24h) for manganese = 148 mg/L

EC50(24h) for the target substance = 148 mg/L/0.075 = 1973.33 mg/L

EC50(48h) for manganese = 146 mg/L

EC50(48h) for the target substance = 146 mg/L/0.075 = 1946.67 mg/L

 

Conclusions:

The reported EC50 values correspond to EC50(24h) values of 1237.33 mg/L for morphology and 1973.33 mg/L for mortality and EC50(48h) values of 1453.33 mg/L and 1946.67 mg/L for morphology and mortality, respectively.

Executive summary:

The data on manganese chloride allows estimating corresponding EC50 values for the target substance. The reported EC50 values correspond to EC50(24h) values of 1237.33 mg/L for morphology and 1973.33 mg/L for mortality and EC50(48h) values of 1453.33 mg/L and 1946.67 mg/L for morphology and mortality, respectively.

Description of key information

In an activated sludge respiration inhibition test (OECD TG 209, GLP) Fe(Na)EDDHA was used as test substances. An EC50(3 h) value of > 1000 mg/L and an EC10 (3 h) of 450 mg/L was obtained (BASF 2010).

Hence, the substance can be regarded as non-toxic to microorganisms present in sewage treatment plants.

With regard to manganese the key value for chemical safety assessment for toxicity to microorganisms is obtained in a growth inhibition study with Tetrahymena pyriformis. An IC50 (9 h) of 210 mg Mn/L was determined (Bogaerts 1998). Converted to the manganese moiety in the target substance taking into account the maximum amount of manganese in the target substance, this key value corresponds to an IC50 (9 h) of 2800 mg/L. For the whole evaluation of the available data on manganese compounds please refer to 'Additional information'.

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

EC10 or NOEC for microorganisms:

450 mg/L

Additional information

Manganese salts

Toxicity data of manganese towards three different species of protozoae is available. The data on manganese compounds allows estimating a corresponding EC for the target substance.

The aim of the study by Klimek et al. (2013) was to assess the toxicity of manganese to the rotifer Lecane inermis, a species tested as a potential biological tool to control activated sludge bulking caused by overgrowth of filamentous bacteria in wastewater treatment plants. LC50 (24 h) value for elemental Mn (2+) was determined to be 1.9194 mg/L. This corresponds to a LC50 (24 h) value of 25.59 mg/L for the manganese moiety in the target substance.

In a 1 h / 9 h toxicity study by Bogaerts et al. (1998), cultures of Tetrahymena pyriformis were exposed to various concentrations of Mn2+ under static conditions. The EC50 (1h) and the IC50 (9h) values based on the metabolic activity and growth inhibition were 26.95 mg/L and 210 mg/L, respectively. The reported EC50(1h) corresponds to a value of 359.33 mg/L and the IC50(9h) is 2800 mg/L for manganese moiety in the target substance.

In a 24 h / 48 h toxicity study, ciliated protozoa (Spirostomum ambiguum) were exposed to various concentrations of Mn2+ under static conditions (Nalecz-Jawecki et al., 1998). EC50 values based on morphology of 92.8 +/- 44.7 mg/L and 109 +/- 66.3 mg/L are obtained after 24h and 48h, respectively. The reported LC50(24h) is 148 +/- 15.5 mg/L, the LC50(48h) is 146 +/- 19.5 mg/L. Converted to the target substance the 24h and the 48h EC50s are 1237.33 mg/L and 1973.33 mg/L, respectively. The reported LC50 correspond to a LC50(24h) of 1453.33 mg/L and a LC50(48h) of 1946.67 mg/L.

 

Table 1: Effect concentrations (EC), Lethal concentrations (LC) and inhibitory concentration (IC) derived from studies performed with various manganese compounds and converted to the target substance.

Species	Duration of exposure	Dose descriptor	target substance (mg/L)	water media type	Reference
Spirostonum ambiguum	24h	EC50	1237.33	freshwater	Nalecz-Jawecki & Sawicki (1998)
Spirostonum ambiguum	48h	EC50	1453.33	freshwater	Nalecz-Jawecki & Sawicki (1998)
Spirostonum ambiguum	24h	LC50	1973.33	freshwater	Nalecz-Jawecki & Sawicki (1998)
Spirostonum ambiguum	48h	LC50	1946.67	freshwater	Nalecz-Jawecki & Sawicki (1998)
Tetrahymena pyriformis	1h	EC50	359.33	freshwater	Bogaerts et al (1998)
Tetrahymena pyriformis	9h	IC50	2800	freshwater	Bogaerts et al (1998)
Lecane inermis	24 h	LC50	25.59	freshwater	Klimek et al. (2013)