N,N-dimethyl-p-toluidine

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Justification for type of information:

Data is from peer reviewed journal

Qualifier:

according to guideline

Guideline:

other: Standard test procedure ASTM, 1980

Version / remarks:

American Society for Testing and Materials, 1980. Standard practice for conducting acute toxicity tests with fishes, macroinvertebrates, and amphibians. Annual Book of ASTM Standards.Philadelphia, PA, E729-80

GLP compliance:

no

Analytical monitoring:

yes

Details on sampling:

- Concentrations: All the exposed test concentrations were analysed immediately Daily determinations for each test treatment were averaged and used as the experimental exposure parameters

Vehicle:

no

Test organisms (species):

Pimephales promelas

Details on test organisms:

Test organism:
- Common name: Fathead Minnow
- Age: 28 to 34 day-old juvenile fathead minnows
- Weight: 0.12 grams

ACCLIMATION
- Acclimation period: All fish were acclimated to the test chambers for 2-3 h before introduction of the toxicants
- Type and amount of food during acclimation: Fishes were not fed during this period

FEEDING DURING TEST: No

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

44.6 ± 1.4 mg/L CaCO3

Test temperature:

25.0 ± 0.5°C.

pH:

7.6 ± 0.2

Dissolved oxygen:

5.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass and silicone sealant
- Renewal rate of test solution (frequency/flow rate): continuous-flow
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): Duplicates

ALKALINITY: 46.1 mg/L CaCO3

Other: Water temperature, dissolved oxygen (DO), pH, hardness, and alkalinity were routinely measured on water from control and treatment chambers according to standard analytical procedures

Reference substance (positive control):

not specified

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

52.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CI of 50 mg/l to 55.6 mg/l

Reported statistics and error estimates:

LC50 values and 95 % confidence intervals were computed by the Trimmed Spearman-Karber Method or a log-probit method.

Validity criteria fulfilled:

not specified

Conclusions:

Based on the mortality of fathead minnows (Pimephales promelas) due to the test chemical exposure for 96 hours, the lethal concentration (LC50) value was determined to be at 52.8 mg/l with 95% CI of 50 mg/l to 55.6 mg/l.

Executive summary:

An acute study was carried out for the determination of effects of test chemical on the mortality rate of fishes. Test conducted in accordance with Standard test procedure ASTM. 28 to 34 day-old juvenile pimephales promelas was used as a test organism. Test chemical was analytically monitorized by using GC and HPLC method. GC analyses were performed on a Hewlett-Packard model 5730 A gas chromatograph equipped with flame ionization and electron capture detectors. And the HPLC analysis was performed on a Waters Associates model 440 or Hewlett-Packard model 1084B liquid chromatograph equipped with a fixed or variable wavelength detector, respectively. Standard curves for analytical confirmation of test concentrations were prepared for each analytical series. Test performed under the flow through system for providing the exposure period of 96 hours. 5 fishes were added in each test and control chamber. All fish were acclimated to the test chambers for 2-3 h before introduction of the toxicants. The fish were not fed 24 h before nor during the toxicity tests.

Test was performed at a temperature of 25.0 ± 0.5°C, hardness of 44.6 ± 1.4 mg/L CaCO3, dissolve oxygen of 5 mg/l and pH 7.6 ± 0.2, respectively. Mortality were recorded dailyand the LC50 values and 95 % confidence intervals were computed by the Trimmed Spearman-Karber Method or a log-probit method. Based on the mortality of fathead minnows (Pimephales promelas) due to the test chemical exposure for 96 hours, the lethal concentration (LC50) value was determined to be at 52.8 mg/l with 95% CI of 50 mg/l to 55.6 mg/l. This LC50 value indicates that the test material was toxic to fish Pimephales promelas and classified in aquaticchronic category 3 as per the CLP classification criteria.

Description of key information

Short term toxicity to Fish

The objective of this study is to assess the Acute Toxicity of test chemical in Freshwater Fish (Danio rerio). Study was performed in compliance with OECD 203 Guideline for the testing of chemicals; Fish, Acute Toxicity Testing, (18th June, 2019). Test chemical was directly dissolved in water without using any carrier solvent, prepared by dissolving 3000 mg in 3000ml on 0^thday. However, since it was a semi static assay therefore the stock solution was prepared daily, and the solubility is determined on daily basis to prepare the test concentrations. On 1st, 2nd, and 3rd day stock solution was prepared by dissolving 1000 mg in 1000 ml of RO water to get the final concentration of 1000 mg/L which was then analytically determined. From stock solutions exposure concentrations were prepared by dilutions. Since the chemical was unstable in exposure media, semi static condition was chosen for main study. The main study was conducted with 5 concentrations based on the previously available data, i.e., 9.62, 17.32, 31.18, 56.12 and 101.01 mg/L with a geometric factor of 1.8 along with one control group. The test concentration was renewed at regular 24 hours of intervals. Each concentration contained seven fish. The test conditions such as temperature, hardness, pH dissolved oxygen and conductivity was 22.4±0.9, 140mg of CaCO3, 8.3 -7.7, 7.0 – 7.1 and 0.4µS/cm respectively. No mortality (percent) observed in control groups and in the tested concentrations of 9.62, 17.32, 31.18, 56.12 mg/L whereas, 100% in 101.01 mg/L for a period of 96 hours. No clinical sign observed in control groups and in all the tested concentrations for a period of 96 hours expect in the highest concentrations fishes were swimming near water surface and movement was slow compared with control. The test item available in the test medium was determined by a validated spectrophotometric method. The test item concentration of test item in the test medium at the initiation 0 hour, 24 hours, 48 hours, 72 hours and 96 hours was measured in all exposed concentrations. which were in the range of 100±20 of the nominal test concentrations presented in additional information on results. As the measured concentrations were within 80 to 120% of the nominal concentration during the definitive test period. Based on the re mortality the median lethal concentration was reported to be > 56.12 (nominal) and 78.62 mg/L (geometric average LC0 and LC100). Based on the 96 hours LC50 value the test chemical can be categorized in chronic category 3 as per CLP classification criteria.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

56.12 mg/L

Additional information

Based on the various experimental studies from different sources including peer reviewed journal, authoritative databases and secondary databases, studies were reviewed for the determination of the effects of test chemical on the mortality of fishes. The studies are as mentioned below:

The objective of this study is to assess the Acute Toxicity of test chemical in Freshwater Fish (Danio rerio). Study was performed in compliance with OECD 203 Guideline for the testing of chemicals; Fish, Acute Toxicity Testing, (18th June, 2019). Test chemical was directly dissolved in water without using any carrier solvent, prepared by dissolving 3000 mg in 3000ml on 0^thday. However, since it was a semi static assay therefore the stock solution was prepared daily, and the solubility is determined on daily basis to prepare the test concentrations. On 1st, 2nd, and 3rd day stock solution was prepared by dissolving 1000 mg in 1000 ml of RO water to get the final concentration of 1000 mg/L which was then analytically determined. From stock solutions exposure concentrations were prepared by dilutions. Since the chemical was unstable in exposure media, semi static condition was chosen for main study. The main study was conducted with 5 concentrations based on the previously available data, i.e., 9.62, 17.32, 31.18, 56.12 and 101.01 mg/L with a geometric factor of 1.8 along with one control group. The test concentration was renewed at regular 24 hours of intervals. Each concentration contained seven fish. The test conditions such as temperature, hardness, pH dissolved oxygen and conductivity was 22.4±0.9, 140mg of CaCO3, 8.3 -7.7, 7.0 – 7.1 and 0.4µS/cm respectively. No mortality (percent) observed in control groups and in the tested concentrations of 9.62, 17.32, 31.18, 56.12 mg/L whereas, 100% in 101.01 mg/L for a period of 96 hours. No clinical sign observed in control groups and in all the tested concentrations for a period of 96 hours expect in the highest concentrations fishes were swimming near water surface and movement was slow compared with control. The test item available in the test medium was determined by a validated spectrophotometric method. The test item concentration of test item in the test medium at the initiation 0 hour, 24 hours, 48 hours, 72 hours and 96 hours was measured in all exposed concentrations. which were in the range of 100±20 of the nominal test concentrations presented in additional information on results. As the measured concentrations were within 80 to 120% of the nominal concentration during the definitive test period. Based on the re mortality the median lethal concentration was reported to be > 56.12 (nominal) and 78.62 mg/L (geometric average LC0 and LC100). Based on the 96 hours LC50 value the test chemical can be categorized in chronic category 3 as per CLP classification criteria.

An acute study was carried out for the determination of effects of test chemical on the mortality rate of fishes. Test conducted in accordance withStandard test procedure ASTM. 28 to 34 day-old juvenile pimephales promelas was used as a test organism. Test chemical was analytically monitorized by using GC and HPLC method. GC analyses were performed on a Hewlett-Packard model 5730 A gas chromatograph equipped with flame ionization and electron capture detectors. And the HPLC analysis was performed on a Waters Associates model 440 or Hewlett-Packard model 1084B liquid chromatograph equipped with a fixed or variable wavelength detector, respectively. Standard curves for analytical confirmation of test concentrations were prepared for each analytical series. Test performed under the flow through system for providing the exposure period of 96 hours. 5 fishes were added in each test and control chamber. All fish were acclimated to the test chambers for 2-3 h before introduction of the toxicants. The fish were not fed 24 h before nor during the toxicity tests.

Test was performed at a temperature of 25.0 ± 0.5°C, hardness of 44.6 ± 1.4 mg/L CaCO3, dissolve oxygen of 5 mg/l and pH 7.6 ± 0.2, respectively. Mortality were recorded dailyand the LC50 values and 95 % confidence intervals were computed by the Trimmed Spearman-Karber Method or a log-probit method. Based on the mortality of fathead minnows (Pimephales promelas) due to the test chemical exposure for 96 hours, the lethal concentration (LC50) value was determined to be at 52.8 mg/l with 95% CI of 50 mg/l to 55.6 mg/l. This LC50 value indicates that the test material was toxic to fish Pimephales promelas and classified in aquaticchronic category 3 as per the CLP classification criteria.

 

Above study further supported by the second study from peer reviewed journal. Principle of this study was to determine the effect of test chemical on the mortality rate of freshwater fishes. Test conducted in accordance withJapan industrial standards. Oryzias latipes was used as a test organism.10 fishes in one trial were used and kept in 2 liters of deionized water.After 48 hours of study, lethal concentration of 50% mortality were determined. Median Tolerance limit (TLm) value of test chemical to fish Oryzias latipes in 24- and 48-hours study on the basis of mortality effect was examined at dose concentration of 44 mg/l and 20 mg/L. This Value indicates that the test chemical was toxic to fish Oryzias latipes.

 

Similarly, in the third supporting study an acute effects of test chemical on fishes Pimephales promelas was determined. Test conducted under theflow-through system for 96 hours. 35 days old Pimephales promelas was used as a test organism. Fishes were collected from US EPA Environmental Research Laboratory. After the exposure period of 96 hours effects on the mortality of fishes were observed.Affected fish lost schooling behaviour and swam near the tank bottom. They were hypoactive and underreactive to external stumuli and has increased respiration.Equilibriums loss was not observed prior to death. Alkalinity value increased with the exposure concentration. Lethal concentration LC50 value and the Effective concentration EC50 value of test chemical to Pimephales promelas in 96 hours study on the basis of mortality effect was determined at dose concentration 52 mg/L. This value indicates that the test chemical was toxic to fishes and classified in aquatic chronic category 3 as per the CLP classification criteria.

 

Principle of this study was to determine the acute effects of test chemical on the mortality of fishes. 32 days old Pimephales promelas was used a test organism. Test conducted under the flow-through system for 96 hours. 0, 19.2, 29.6, 45.6, 70.2 and 108 mg/L nominal test concentrations ere used in the study. Affected fish lost schooling behaviours and swam near the tank bottom. They were hypoactive and underreactive to external stumuli and has increased respiration. Initial dissolve oxygen values were less than 60% of saturation. equilibrium loss was not observed prior to death. The measured tank value was lower than the nominal values. Alkalinity value increased with the exposure concentration. They were due to a reaction between the titrant and the toxicant. Lethal concentration (LC50) value of test chemical to fish in 96 hours study on the basis of mortality effect was examined at dose concentration of 46 mg/L. Effective concentration (EC50) value of test material to Pimephales promelas in 96 hours study on the basis of mortality effect was determined at dose concentration of 41.5 mg/L. This value indicates that the test chemical was toxic to fishes and classified in aquatic chronic category 3 as per the CLP classification criteria.

 

The fifth study was also supporting the classification of target chemical. Principle of this study was to determine the effect of test chemical on the mortality rate of fishes. Test conducted under theflow through system for 96 hours. Freshwater Pimephales promelas was used as a test organism. After the exposure of chemical with fishes, effects on the mortality rate were measured. The effect of the test material on fishes Pimephales promelas was evaluated for 96 h in flow through condition. The Lethal concentration i.e. LC50 value of test chemical was observed to be 48.9 mg/l. Thus, on the basis of LC50 value, test chemical considered to be toxic and classified in aquatic chronic category 3 as per the CLP classification criteria.

 

Thus, on the basis of above all studies from various sources, test chemical considers to be toxic and classified in aquatic chronic category 3 as per the CLP classification criteria.