3,7-bis(diethylamino)phenoxazin-5-ium tetrachlorozincate (2:1)

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

Data is from OECD QSAR toolbox version 3.3 and the QMRF report has been attached.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

Prediction was done using the OECD QSAR toolbox version 3.3.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (IUPAC name): 3,7-bis(diethylamino)phenoxazin-5-ium tetrachlorozincate (2:1)
- Molecular formula: C40H52Cl4N6O2Zn
- Molecular weight: 856.093 g/mol
- Smiles notation: [o+]1c2cc(ccc2nc2ccc(N(CC)CC)cc12)N(CC)CC.[Zn+2].[ClH-].[ClH-].[ClH-].[ClH-].[o+]1c2cc(ccc2nc2c1cc(cc2)N(CC)CC)N(CC)CC
- InChl: 1S/2C20H26N3O.4ClH.Zn/c2*1-5-22(6-2)15-9-11-17-19(13-15)24-20-14-16(23(7-3)8-4)10-12-18(20)21-17;;;;;/h2*9-14H,5-8H2,1-4H3;4*1H;/q2*+1;;;;;+2/p-4
- Substance type: Organic
- Physical state:

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Hardness:

No data available

Test temperature:

25.8 to 26.0 degree C

pH:

7.63 to 8.13

Dissolved oxygen:

No data available

Salinity:

No data available

Conductivity:

No data available

Nominal and measured concentrations:

Estimated

Details on test conditions:

No data available

Reference substance (positive control):

not specified

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.241 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Toxic to aquatic algae

Details on results:

After the exposure of chemical, the EC50 was 0.2410 mg/l.

The prediction was based on dataset comprised from the following descriptors: EC50
Estimation method: Takes average value from the 5 nearest neighbours
Domain  logical expression:Result: In Domain

(((((("a" or "b" or "c" )  and ("d" and ( not "e") )  )  and "f" )  and ("g" and ( not "h") )  )  and "i" )  and ("j" and "k" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Zinc metal and salts by OECD HPV Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Soluble complexes of Zinc by US-EPA New Chemical Categories

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion formation AND SN1 >> Nitrenium Ion formation >> Tertiary aromatic amine by DNA binding by OECD

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as SHOULD NOT BE PROFILED by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Acid moiety by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Class 5 (Not possible to classify according to these rules) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Halogens AND Non-Metals AND Transition Metals by Groups of elements

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Alkali Earth by Groups of elements

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Aromatic amine AND Aryl AND Fused carbocyclic aromatic AND Fused heterocyclic aromatic by Organic Functional groups ONLY

Domain logical expression index: "j"

Parametric boundary:The target chemical should have a value of log Kow which is >= -0.522

Domain logical expression index: "k"

Parametric boundary:The target chemical should have a value of log Kow which is <= 11.4

Validity criteria fulfilled:

not specified

Conclusions:

Thus based on the growth inhibition of algae, the EC50 value was estimated to be 0.2410 mg/l when 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) exposed to Pseudokirchneriella subcapitata for 72hrs.

Executive summary:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the six closest read across substances, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) (63589 -47 -9). The EC50 value was estimated to be 0.2410 mg/l when 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) exposed to Pseudokirchneriella subcapitata for 72hrs. Thus, based on this value, it can be concluded that the test chemical 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) can be considered as toxic to aquatic organisms and thus can be classified as aquatic acute 1 and chronic category 1 as per the CLP criteria.

Description of key information

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the six closest read across substances, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) (63589 -47 -9). The EC50 value was estimated to be 0.2410 mg/l when 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) exposed to Pseudokirchneriella subcapitata for 72hrs. Thus, based on this value, it can be concluded that the test chemical 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) can be considered as toxic to aquatic organisms and thus can be classified as aquatic acute category 1 as well as chronic 1 as per the criteria mentioned in CLP.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.241 mg/L

Additional information

Based on the various experimental data and prediction data for the target chemical as well as RA chemical which was selected on the basis of structure similarity study have been reviewed to determine the toxic nature of 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) (63589-47-9) on the growth of algae and cyanobacteria. The studies are as mentioned below: 

In the first predicted weight of evidence report for the 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) (63589-47-9) from SSS (QSAR, 2017) toxicity study was carried out. Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the six closest read across substances, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) (63589 -47 -9). The EC50 value was estimated to be 0.2410 mg/l when 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) exposed to Pseudokirchneriella subcapitata for 72hrs. Thus, based on this value, it can be concluded that the test chemical 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) can be considered as toxic to aquatic organisms and thus can be classified as

aquatic acute category 1 as well as chronic 1 as per the criteria mentioned in CLP.

Similarly in the second prediction study which was performed based on the prediction done using the EPI Suite ECOSAR version 1.10, the short term toxicity on green algae was predicted for test substance 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) (63589 -47 -9). On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) is estimated to be 0.589 mg/l for green algae for 96 hrs duration. Based on this value, it can be concluded that the test chemical 3,7-bis(diethylamino)phenoxazin-5-ium tetrachlorozincate (2:1) can be considered as toxic to green algae at environmentally relevant concentrations and can be considered as classified as aquatic acute category 1 as well as chronic 1 as per the criteria mentioned in CLP.

Similarly in the third weight of evidence study for the read across (548-62-9) (from Intox Pvt. Ltd. 2010) toxicity was conducted on Pseudokirchneriella subcapitata to determine the toxic nature of chemical. Freshwater Alga, Growth Inhibition Test of 4-{bis[4-(dimethylamino)phenyl]methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium chloride in fresh water Unicellular green alga, Pseudokirchneriella subcapitata (Selenastrum capricornutum) was performed in compliance with the OECD Guidelines for Testing of Chemicals, Section 2, No. 201, "Fresh water Alga and Cyanobacteria, Growth Inhibition Test". 4-{bis[4-(dimethylamino)phenyl]methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium chloride was tested for its possible inhibitory effect on growth of alga, Pseudokirchneriella subcapitata. Exponentially growing cultures of the algae were exposed to test article at concentrations levels of 0.025 mg, 0.05 mg, 0.1 mg, 0.2 mg, 0.4 and 0.8 mg/L for a period of 72 hours, along with a concurrent blank control. Potassium Dichromate, serving as a positive control, was also concurrently tested at concentrations levels of 0.4 mg, 0.8 mg and 1.6 mg/L. The cell concentration, i.e. the number of cells per ml, for all the concentration levels, was counted at 24, 48 and 72 hours of start of the exposure by counting them under microscope in a haemocytometer counting chamber and the inhibition of growth in relation to the control culture was determined. The endpoint was inhibition of growth, expressed as the logarithmic increase in biomass (average specific growth rate) during the exposure period. From the average specific growth rates recorded in a series of test solutions, the concentration bringing about 50% inhibition of growth rate was determined and expressed as the ErC50. The additional endpoint was inhibition of yield, expressed as the biomass at the end of exposure period minus the biomass at the start of the exposure period. From the yield recorded in a series of test solutions, the concentration bringing about 50% inhibition of yield was determined and expressed as the EyC50. In the present study, percent inhibition of growth in fresh water unicellular green alga, Pseudokirchneriella subcapitata at 72 h, was 3.62%, 5.82%, 9.82%, 20.88%, 47.95 and 72.83 % recorded at the concentrations of 0.025 mg, 0.05 mg, 0.1 mg, 0.2 mg, 0.4 and 0.8 mg/L respectively. In positive control group percent inhibition of growth in fresh water unicellular green alga, Pseudokirchneriella subcapitata at 72 h, was 21.01%, 65.18% and 90.97% recorded at the concentrations of 0.4 mg, 0.8 mg and 1.6 mg/L respectively. In the present study, percent inhibition in yield in fresh water unicellular green alga, Pseudokirchneriella subcapitata at 72 h, was 10.45%, 16.37%, 25.64%, 47.73%, 79.29% and 92.90% recorded at the concentrations of 0.025 mg, 0.05 mg, 0.1 mg, 0.2 mg, 0.4 mg and 0.8 mg/L respectively. In positive control group percent yield in fresh water unicellular green alga, Pseudokirchneriella subcapitata at 72 h, was 48.13%, 89.74% and 98.22% recorded at the concentrations of 0.4 mg, 0.8 mg and 1.6 mg/L respectively. On the basis of observations made during this test, the ErC50(72h) of 4-{bis[4-(dimethylamino) phenyl]methylidene}-N,N-dimethylcyclohexa-2,5 dien-1-iminium chloride inducing inhibition of the growth of fresh water unicellular green algae Pseudokirchneriella subcapitata was determine to be 0.42 mg/L with fiducial limits between 0.19 to 0.93 mg/L at 95% confidence level. On the basis of observations made during this test, the EyC50(72h) of 4-{bis[4-(dimethylamino)phenyl] methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium chloride inducing inhibition of the yield of fresh water unicellular green algae Pseudokirchneriella subcapitata was determine to be 0.21 mg/L with fiducial limits between 0.11 to 0.40 mg/L at 95% confidence level. Thus on the basis of EcC50 and EyC50 value it can be concluded that the 4-{bis[4-(dimethylamino) phenyl]methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium chloride is toxic to the aquatic environment and can be considered as "Aquatic Acute 1" and chronic 1as per CLP regulation.

 

Thus based on the above data sources for target chemical 3,7-bis(diethylamino)phenoxazin-5-iumtetrachloro- zincate (2:1) (63589-47-9) from various experimental studies and predicted studies from QSAR, EPIsuite, Intox 2010, it was summarized that the chemical was toxic to aquatic organisms and thus can be classified as aquatic acute category 1 as well as chronic 1 as per the criteria mentioned in CLP.