OligoActiv EDDHA-Mn

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

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:

72 h

Dose descriptor:

EC50

Effect conc.:

> 294 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

8.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

29.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

27.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

2.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

8.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

After 72 h exposure, in test groups up to 32 mg/L no remarkable observations were reported. Concerning the test groups with 100 and 320 mg/L, a low cell density was recorded.

Results with reference substance (positive control):

According to the test ISO guideline 8692 the EC50 values of the reference substance potassium dichromate should be in the range: ErC50 = 0.71 – 0.97 mg/L after 72 hours for Desmodesmus subspicatus. The ErC50(72 h) of the control substance potassium dichromate was 0.82 mg/L. These results indicate that the algae are responding normally to toxicant stress.

Reported statistics and error estimates:

No statistics and error estimates reported.

Validity criteria fulfilled:

yes

Remarks:

The test conformed to all validity criteria of the OECD Guideline used and is valid.

Conclusions:

In conclusion the 72 hour EC50 value for FeNaEDDHA with Desmodesmus subspicatus CHODAT (SAG 86.81) was > 294 mg/L and the NOEC was 8.2 mg/L based on algal growth rate. The 72 hour EC50 based on yield was 27.3 mg/L and the NOEC 2.4 mg/L. 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 toxic effects of Fe(Na)EDDHA on the growth of single-cell green algae as representatives of primary producers in freshwater plankton over a 72 hour static exposure period were determined according to the principles of OECD Guideline 201 and EU Method C.3.

The following nominal concentrations based on test substance mass without a correction for purity were used: 3.2, 10, 32, 100, 320 mg/L. The analytically determined concentrations of the test substance in the test water were in a range of 89 - 102 % of the nominal concentration at start of exposure and decreased to 63 - 86 % of the nominal concentration at the end of exposure. Therefore mean measured concentrations were considered to be an accurate representation of exposure levels throughout the exposure period.

The 72-hour EC50 value for Desmodesmus subspicatus CHODAT (SAG 86.81) was greater than 294 mg/L and the NOEC was 8.2 mg/L based on mean measured concentrations and growth rate. The 72 hour EC50 based on yield and mean measured concentrations was 27.3 mg/L and the NOEC was 2.4 mg/L.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

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:

21 d

Dose descriptor:

EC50

Effect conc.:

666.67 mg/L

Conc. based on:

element

Remarks:

converted to the target substance

Basis for effect:

other: total algal cell volume

Remarks on result:

other: Duration is an approximation

Calculation of the EC50 for the target substance:

EC50 for manganese = 50 mg/L

 

The concentration of manganese in the target substance is 7.5 %, therefore, the EC50 has to be recalculated: 50 mg/L/0.075 = 666.67 mg/L.

 

The calculated EC50 value of the target substance in Chlorella stigmatophora is 666.67 mg/L.

Conclusions:

The calculated EC50 value of the target substance in Chlorella stigmatophora is 666.67 mg/L.

Executive summary:

The data on manganese allows estimating a corresponding 21d EC50 for the target substance.

The calculated EC50 value of the target substance in Chlorella stigmatophora is 666.67 mg/L.

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

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:

14 d

Dose descriptor:

EC50

Effect conc.:

41.33 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

other: total algal cell volume

Remarks on result:

other: test duration is an approximation

Calculation of the EC50 for the target substance:

EC50 for manganese = 3.10 mg/L

 

The concentration of manganese in the target substance is 7.5 %, therefore, the EC50 has to be recalculated: 3.1 mg/L/0.075 = 41.33 mg/L.

 

The calculated EC50 value of the target substance in Selenastrum capricornutum is 41.33 mg/L.

Conclusions:

 The calculated EC50 value of the target substance in Selenastrum capricornutum is 41.33 mg/L.

Executive summary:

The data on manganese allows estimating a corresponding 14d EC50 for the target substance. The calculated EC50 value of the target substance in Selenastrum capricornutum is 41.33 mg/L.

Reference 4

Endpoint:

toxicity to aquatic algae and cyanobacteria

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:

10 d

Dose descriptor:

EC50

Effect conc.:

ca. 3 806.4 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

other: count of surviving colonies

Remarks on result:

other: Results for Chroococcus limneticus

Duration:

10 d

Dose descriptor:

EC50

Effect conc.:

ca. 146.4 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

other: count of surviving colonies

Remarks on result:

other: Results for Plectonema boryanum

Duration:

10 d

Dose descriptor:

EC10

Effect conc.:

ca. 1 024.8 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

other: count of surviving colonies

Remarks on result:

other: Results for Chroococcus limneticus

Duration:

10 d

Dose descriptor:

EC10

Effect conc.:

ca. 21.96 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

converted to target substance

Basis for effect:

other: count of surviving colonies

Remarks on result:

other: Results for Plectonema boryanum

Calculation of the EC50 for the target substance:

concentration of manganese in the target substance: 7.5 %

Chroococcus limneticus

EC50 for manganese = 285.5 mg/L

 

EC50 for the target substance = 285.5 mg/L/0.075 = 3806.4 mg/L.

 

EC10 for manganese = 76.9 mg/L

 

EC10 for the target substance = 76.9 mg/L/0.075 = 1024.8 mg/L.

Plectonema boryanum

EC50 for manganese = 11 mg/L

 

EC50 for the target substance = 11 mg/L/0.075 = 146.4 mg/L.

 

EC10 for manganese = 1.7 mg/L

 

EC10 for the target substance = 1.7 mg/L/0.075 = 21.96 mg/L.

Conclusions:

Converted to the Mn concentration in the target substance the 10d EC50 is 146.4 mg/L for Plectonema boryanum and 3806.4 mg/L for Chroococcus limneticus. The 10d EC10 are 21.96 mg/L and 1024.8 mg/L for Plectonema boryanum and Chroococcus limneticus.

Executive summary:

The data on manganese sulfate given as mmol Mn/L (or mg Mn/L) allows estimating corresponding 10d EC50 and 10d EC10 for the target substance.

The resulting 10d EC50 is 146.4 mg/L for Plectonema boryanum and 3806.4 mg/L for Chroococcus limneticus. The 10d EC10 are 21.96 mg/L and 1024.8 mg/L for Plectonema boryanum and Chroococcus limneticus.

Description of key information

Fe(Na)EDDHA was tested in Desmodesmus subspicatus (OECD TG 201, GLP). An E_rC50(72h) of > 294 mg/L and a NOEC_r of 8.2 mg/L were reported (Salinas 2010).

With regard to manganese the key value for chemical safety assessment for freshwater algae is set to the lowest reported EC50 value of 3.1 mg Mn/L obtained for Pseudokirchneriella subcapitata in a 14 d study (Christensen 1979). 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 EC50 (14 d) of 41 mg/L for the target substance. For the whole evaluation of the available data on manganese compounds please refer to 'Additional information'.

Key value for chemical safety assessment

EC50 for freshwater algae:

41 mg/L

Additional information

Manganese chloride

In the available studies three different freshwater algae (Selenastrum capricornutum, Chroococcus limneticus and Chlorella stigmatophora) were used as test organisms. The reported effect concentrations (EC10 and EC50) for the test substances were stated as mg Mn/L.

The data on manganese compounds allow estimating a corresponding EC for the manganese moiety of the target substance. 

 

Algal assays were conducted by Christensen et al (1979) to observe the response of the freshwater alga Selenastrum capricornutum and the marine algae Chlorella stigmatophora to the metals manganese, copper and lead added singly or in combination to both artificial media and natural waters. Thereby, only the effects induced by manganese in artificial waters are of importance for this read-across purpose.

Growth rates and average cell volumes were assessed by the authors. While the growth rate, based on cell volume, in all cases decreased with increasing metal concentration, the average cell volume does not follow a similarly, consistent pattern. Manganese has only a slight effect on the average cell volume. It is concluded that main effects and interactions occur rather regarding to the total cell number than concerning the total cell volume. This means that the cell volume as a measure of the total biomass is less affected by manganese than the total cell number.

The marine water algae Chlorella stigmatophora showed a 50 % reduction in the total algal cell volume in 28 ppt ASW plus full SAAM (standard algal assay medium) nutrients in the presence of 50 mg manganese per liter added singly. The study was conducted for approximately 21 days, so the reported concentration of 50 mg/L is regarded as the 21d EC50. The corresponding 21d EC50 for the manganese moiety in the target substance is calculated to be 666.67 mg/L for Chlorella stigmatophora.

 

Christensen et al (1979) also assay the freshwater algae Selenastrum capricornutum in SAAM. A 50 % reduction in the total algal cell volume occurs in the presence of 3.1 mg manganese per liter added singly. The study was conducted for approximately 14 days, so the reported concentration of 3.1 mg/L is regarded as the 14d EC50. This value corresponds to a 14d EC50 of 41.33 mg/L for the manganese moiety of the target substance for Selenastrum capricornutum.

 

The effect of manganese chloride on Chroococcus limneticus and two mutants of Plectonema boryanum was investigated by Singh and Kashyap (1978). In a 10 d toxicity study, cultures of Chroococcus limneticus and Plectonema boryanum were placed on nutrient agar plates with various concentrations of MnCl₂ incorporated (1 -10 mM), i.e. under static conditions. The EC50 and the EC10 values based on the count of surviving colonies were 5.2 mmol/L and 1.4 mmol/L for C. limneticus and 0.2 mmol/L and 0.03 mmol/L for P. boryanum, respectively. The following abnormalities were noted: asymmetry in cell division, abnormal cell enlargement. The corresponding 10d EC50 for the manganese moiety of the target substance is 146.4 mg/L for Plectonema boryanum and 3806.4 mg/L for Chroococcus limneticus. The 10d EC10 are 21.96 and 1024.8 mg/L for Plectonema boryanum and Chroococcus limneticus, respectively.

 

 

Conclusion

The EC50 values converted to the manganese moiety in the registered substance range from 41.33 to 3806.4 mg/L for various different freshwater species and the 10d EC10 values range from 21.96 to 1024.8 mg/L. The key value for chemical safety assessment for freshwater algae is set to the lowest reported EC50 value of 41.33 mg/L which was obtained for Selenastrum capricornutum (Pseudokirchneriella subcapitata) within a 14 d study by Christensen et al (1979).

 

Table 1: Effect concentrations (EC) derived from studies performed with manganese chloride converted to the target substance.

Species	Duration of exposure	Dose descriptor	target substance (mg/L)	Impact	Reference
Chlorella stigmatophora	21d	EC50	666.67	salt water	Christensen et al, 1979
Selenastrum capricornutum	14d	EC50	41.33	freshwater	Christensen et al, 1979
Chroococcus limneticus	10d	EC50	3806.4	freshwater	Singh and Kashyap, 1975
Plectonema boryanum	10d	EC50	146.4	freshwater	Singh and Kashyap, 1975
Chroococcus limneticus	10d	EC10	1024.8	freshwater	Singh and Kashyap, 1975
Plectonema boryanum	10d	EC10	21.96	freshwater	Singh and Kashyap, 1975