N,N-dimethyl-p-toluidine

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

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:

ECOSAR estimates log Kow values using the US EPA's KOWWIN Program for aquatic toxicity.Toxicity of a chemical was measured on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program based upon the octanol /water partition coefficient (Kow). Data from ECOSAR class,neutral organics was used.

The estimation methods in EPI Suite™ have been developed by government, academic, and private sector researchers over many years and represent some of the best techniques currently available. The intended application domain of EPI Suite is organic chemicals, and inorganic as well as organometallic chemicals generally can be considered outside the domain.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

- Common name: Water flea

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

15.27 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: Neutral Organics

Validity criteria fulfilled:

not specified

Conclusions:

On the basis of EPI suite, ECOSAR version, the LC 50 value for short term toxicity to aquatic invertebrates was predicted to be 15.270 mg/l for test material in 48 hrs.
Based on this value, it can be concluded that the substance was considered to be toxic to aquatic environment and classified in aquatic chronic 3 category as per the criteria mentioned in CLP regulation.

Executive summary:

Based on the prediction done by EPI suite, ECOSAR version 1.11, on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program, the LC 50 value for short term toxicity to aquatic invertebrates was predicted.

On the basis of this program, the LC 50 value for short term toxicity to aquatic invertebrates was predicted to be  15.270 mg/l for test chemical in 48 hrs.

Based on this value it can be concluded that the substance was considered to be  toxic to aquatic environment and can be classified in aquatic chronic  3 category as per the criteria mentioned in CLP regulation.

Description of key information

Short term toxicity to daphnia magna

The effect of test chemical was studied on fresh water invertebrate daphnia magna STRAUS strain by following OECD 202 guidelines adopted on 13 april 2014, to assess the acute toxicity of test chemical following exposure of daphnids up to 48h by static method. The brood daphnids were acclimatized 48 hours prior to the test item exposure. Less than 24 h old daphnids were collected from the acclimatized gravid females and exposed to the test item. After exposure on day 0, daphnids were observed for immobilization at 24 and 48 h. M7 medium was used as control, and the same was used for test item formulation . 25 mL glass beakers having a solution volume of 20 mL were used in the test. . Main study (using a spacing factor of 2) was conducted using 0 (control), 2.5,5,10,20,40 mg/L mg/L concentrations. 4 replicates/concentration having 5 daphnids/replicate was used for the main study. Normal behavioural response and no immobilization (0% mortality) were observed up to 48 h in control groups but 25%, 30%, 45% 75% and 100% immobilisation were observed in the test concentrations of  2.5,5,10,20,40 mg/L, respectively. UV-Visible spectrophotometer method was used for active ingredient analysis along with stability of the test item in the test medium. Test item was found to be unstable in the test medium. The active ingredient content results were not within the considered acceptable (80 -120%) as during main study 0 h and 48 h avg. recovery for 2.5,5,10,20,40 mg/L, conc at 0 hour were 88.8%, 82.4%, 81.1%, 84.5% and 82.2% respectively. after 48 hours of exposure, which were found to not in acceptable range. Hence the results were based on measure and nominal concentration since the deviation in the initial measured concentration exceed 20%. Environmental parameters such as pH (7.9 -7.2), temperature (19.7 ± 0.7 °C), dissolve oxygen (7.6 - 7.2 mg/L), hardness (>140 mg CaCO3/L), conductivity (0.20 µS/cm), photoperiod (16 h light- 8 h dark) was maintained in acceptable range throughout the test. Feed was not provided during the test. The 48-h EC50of test chemical to daphnid, Daphnia magna are 10.34 mg/L ( nominl concentration) and 8.44 mg/L ( Initial Measured concentration). The 48-h EC50of reference item (Potassium dichromate) to daphnid, Daphnia magna(found to be in acceptable range) is 1.33 mg/L. Hence, the results of the test with reference item establish the acceptability of the test system response, test procedures followed, and results obtained with test item. 48h EC50 value with 95% confidence limits (upper limit, lower limit) were calculated by probit analysis using STAT plus Software, version 8. Hence, as per CLP classification category the test chemical can be categorized as Chronic Category 3.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

10.34 mg/L

Additional information

Based on the various predicted and experimental studies from different sources, studies were reviewed for the determination of the effects of test chemical and structurally and functionally similar read across chemicals on the mobility of aquatic invertebrates. The studies are as mentioned below:

The effect of test chemical was studied on fresh water invertebrate daphnia magna STRAUS strain by following OECD 202 guidelines adopted on 13 april 2014, to assess the acute toxicity of test chemical following exposure of daphnids up to 48h by static method. The brood daphnids were acclimatized 48 hours prior to the test item exposure. Less than 24 h old daphnids were collected from the acclimatized gravid females and exposed to the test item. After exposure on day 0, daphnids were observed for immobilization at 24 and 48 h. M7 medium was used as control, and the same was used for test item formulation . 25 mL glass beakers having a solution volume of 20 mL were used in the test. . Main study (using a spacing factor of 2) was conducted using 0 (control), 2.5,5,10,20,40 mg/L mg/L concentrations. 4 replicates/concentration having 5 daphnids/replicate was used for the main study. Normal behavioural response and no immobilization (0% mortality) were observed up to 48 h in control groups but 25%, 30%, 45% 75% and 100% immobilisation were observed in the test concentrations of  2.5,5,10,20,40 mg/L, respectively. UV-Visible spectrophotometer method was used for active ingredient analysis along with stability of the test item in the test medium. Test item was found to be unstable in the test medium. The active ingredient content results were not within the considered acceptable (80 -120%) as during main study 0 h and 48 h avg. recovery for 2.5,5,10,20,40 mg/L, conc at 0 hour were 88.8%, 82.4%, 81.1%, 84.5% and 82.2% respectively. after 48 hours of exposure, which were found to not in acceptable range. Hence the results were based on measure and nominal concentration since the deviation in the initial measured concentration exceed 20%. Environmental parameters such as pH (7.9 -7.2), temperature (19.7 ± 0.7 °C), dissolve oxygen (7.6 - 7.2 mg/L), hardness (>140 mg CaCO3/L), conductivity (0.20 µS/cm), photoperiod (16 h light- 8 h dark) was maintained in acceptable range throughout the test. Feed was not provided during the test. The 48-h EC50of test chemical to daphnid, Daphnia magna are 10.34 mg/L ( nominl concentration) and 8.44 mg/L ( Initial Measured concentration). The 48-h EC50of reference item (Potassium dichromate) to daphnid, Daphnia magna(found to be in acceptable range) is 1.33 mg/L. Hence, the results of the test with reference item establish the acceptability of the test system response, test procedures followed, and results obtained with test item. 48h EC50 value with 95% confidence limits (upper limit, lower limit) were calculated by probit analysis using STAT plus Software, version 8. Hence, as per CLP classification category the test chemical can be categorized as Chronic Category 3.

 

Based on the prediction done by EPI suite, ECOSAR version 1.11, on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program, the LC 50 value for short term toxicity to aquatic invertebrates was predicted. On the basis of this program, the LC 50 value for short term toxicity to aquatic invertebrates was predicted to be 15.270 mg/l for test chemical in 48 hrs. Based on this value it can be concluded that the substance was considered to be  toxic to aquatic environment and can be classified in aquatic chronic  3 category as per the criteria mentioned in CLP regulation.

 

Above data further supported by the second study from peer reviewed journal. Principle of this study was to determine the effect of test chemical on the mobility of aquatic invertebrates. 24 hours old Daphnia magna was used as a test organism. The stock solutions were prepared before 24 hours of the experiments in Dutch standard water (DSW) and stirred until use. Test organism were starved from 24 hours before the experiment until the end, when they were sacrificed by immersion in liquid nitrogen. Test conducted under the static system by providing the exposure period of 48 hours of chemical with aquatic invertebrates Daphnia magna. Based on the immobility of Daphnia magna due to the test chemical exposure for 48 hours, the EC50 value was determined to be 13.7 mg/l. This value indicates that the test chemical was toxic and classified in aquatic chronic category 3 as per the CLP classification criteria.

 

Similarly in this experimental study the effect of test chemical was studied on the immobility of aquatic invertebrate Daphnia magna. Test conducted under the static system for 48 hours. Based on the data obtained from the reliable sources, the immobility of Daphnia magna due to the test chemical exposure was observed. The EC50 value was observed to be at 15 mg/l after the exposure period of 48 hours. Thus, based on the EC50 value, test chemical considers to be toxic and classified in aquatic chronic category 3 as per the CLP classification criteria.

Similarly, an acute immobilisation test was conducted for 48 hrs for assessing the short-term toxicity of test chemical to aquatic invertebrate.Study was performed according to the “OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)”.Daphnia magna was used a test organism. The stock solution 100 g/L was prepared in solvent acetone. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample in reconstituted test water.0, 5, 10, 20, 40 and 80 mg/L respectively nominal concentrations were used in this study.Effects on immobilisation were observed for 48 hours and conducted under the static system. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical,effect concentration EC50 value was calculated using nonlinear regression by the software Prism 4.0.Based on the immobility of Daphnia magna due to the test chemical exposure for 48 hours, the EC50 value was observed to be 32.6 mg/l with the CI of 24.9 mg/l to 42.6 mg/l. Thus, based on EC50 value, test chemical considers to be toxic and classified in aquatic chronic category 3 as per the CLP classification criteria.

Thus on the basis of above all studies and effects observation, it is concluded that the test chemical consider to be toxic and classified in aquatic chronic category 3 as per the CLP classification criteria.