Methyl 5-nitrohydrogen.isophthalate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Data is from computational model developed by USEPA

Justification for type of information:

Data is from computational model developed by USEPA

Qualifier:

according to guideline

Guideline:

other: Modeling database

Principles of method if other than guideline:

Estimation of 96 hr EC50 value of test chemical by modelling Database - ECOSAR v.1.11. The ECOSAR Class Program is a computerized version of the ECOSAR analysis procedures as currently practiced by the Office of Pollution Prevention and Toxics (OPPT).  It has been developed within the regulatory constraints of the Toxic Substances Control Act (TSCA).  It is a pragmatic approach to SAR. The structure-activity relationships (SARs) presented in this program are used to predict the aquatic toxicity of chemicals based on their similarity of structure to chemicals for which the aquatic toxicity has been previously measured.  Most SAR calculations in the ECOSAR Class Program are based upon the octanol/water partition coefficient (Kow).  Various surfactant SAR calculations are based upon the average length of carbon chains or the number of ethoxylate units.

GLP compliance:

not specified

Analytical monitoring:

not required

Vehicle:

not specified

Test organisms (species):

other: green algae

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Remarks on exposure duration:

Estimated data

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

166.185 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Neutral Organics SAR (Baseline Toxicity)

Validity criteria fulfilled:

not specified

Conclusions:

The estimated EC50 values for aquatic green algae after 96 hours was 166.185 mg/l on the basis of growth rate.

Executive summary:

The short-term toxicity of the test substance to green algae is predicted using EPI Suite ECOSAR version 1.10. On the basis of effects observed in a static freshwater system during a 96 hr exposure, the effect concentration (EC50) for the substance is estimated to be 166.185 mg/L. Based on this value, it can be concluded that the test chemical can be considered as non-toxic to green algae at environmentally relevant concentrations and can be considered not-classified as per the CLP classification criteria.

 

Description of key information

Toxicity to aquatic algae and cyanobacteria:

The short-term toxicity of the test substance to green algae is predicted using EPI Suite ECOSAR version 1.10. On the basis of effects observed in a static freshwater system during a 96 hr exposure, the effect concentration (EC50) for the substance is estimated to be166.185mg/L. Based on this value, it can be concluded that the test chemical can be considered as non-toxic to green algae at environmentally relevant concentrations and can be considered not-classified as per the CLP classification criteria.

 

Key value for chemical safety assessment

EC50 for freshwater algae:

166.185 mg/L

Additional information

Toxicity to aquatic algae and cyanobacteria:

The toxicity of test material was evaluated on aquatic algae and cyanobaccteia by considering prediction along with data for structurally similar read across substance.

Based on the prediction using EPI Suite ECOSAR version 1.10. On the basis of effects observed in a static freshwater system during a 96 hr exposure, the effect concentration (EC50) for the substance is estimated to be166.185mg/L. Based on this value, it can be concluded that the test chemical can be considered as non-toxic to green algae at environmentally relevant concentrations and can be considered not-classified as per the CLP classification criteria.

The above prediction was supported by data for read across substance study was performed to evaluate the nature and effect of test chemical when it comes in contact with the aquatic algae Scenedesmus subspicatus. Test conducted according to the OECD guideline 201.

  Based on the growth rate inhibition of Scenedesmus subspicatus (green algae) due to the test chemical the NOEC was 969 mg/l. As at 969 mg/ no effect were observed on the growth of algae so it can be consider that the concentration at which 50% growth inhibited was > 969 mg/l. hence on the basis of this phenomenon it can be concluded that the chemical was nontoxic and can be consider to be not classified as per the CLP classification criteria.

The above study was further supported by data for structutrally similar read across substance freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance for total exposure period of 72 hrs. Test conducted according to OECD Guideline 201. The stock solution 100 mg/l was prepared by dissolving white powder in OECD growth medium. Test solutions of required concentration were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at the concentrations 0, 10, 18, 32, 58, 100  mg/L. Effects on the growth rate of the organism were studied by using positive reference substance Potassium dichromate (K2Cr2O7).

The median effective concentration (EC50) for Potassium dichromate in Desmodesmus subspicatus was determined to be 0.77 mg/L. The median effective concentration (EC50) for the test substance, in Desmodesmus subspicatus was determined to be 106.4 mg/L with 95% CI was 98.6 - 114.9 mg/l.

This value indicates that the substance test substance is likely to be non-hazardous to aquatic algae and cannot be classified as toxic and not classified as per the CLP criteria.