4-mesyl-2-nitrotoluene

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 Jul 2005 - 10 Aug 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant, guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

yes

Remarks:

Test temperature briefly above protocol range. This is not deemed to have affected the quality or integrity of the study.

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Duplicate samples were taken from all test concentrations and the control on each analytical sampling period. Samples of newly prepared solutions were taken on days 0, 2, 7, 14 and 19. Samples of 'old' solutions at the end of each renewal period were taken on days 2, 5, 9, 16 and 21.
- Sampling method: For 'new' samples, taken from excess test solutions after filling test vessels. For the 'old' samples, taken from the first vessel of each test concentration, sampled from approximately 1 cm below the surface of one of the replicate vessels.
- Sample storage conditions before analysis: If not analysed directly samples were frozen until analysis carried out.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A solution of 64 mg/L (the highest test concetration) was prepared by completely dissolving 128 mg test material in 2 L test water using Sonification and stirring. Stock solution was diluted with test water to prepare the lower test concentrations. The test media were freshly prepared before the start of the test and prior to each medium renewal.
- Controls: Yes, blank control of test water
- Evidence of undissolved material (e.g. precipitate, surface film, etc): None

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain/clone: Straus 1820, Clone 5
- Source: Brixham Environmental Laboratory, Brixham, Devon, TQ5 8BA, UK.
- Age of parental stock (mean and range, SD): <24 h and not first brood progeny. At the start of the test the test animals were less than 24 hours old.
- Feeding during test
- Food type: Chlorella vulgaris and Tetramin suspension to each vessel.
- Amount: 0.2 mg TOC/Daphnia daily
- Frequency: Daily

ACCLIMATION
- Acclimation period: Parental stock culture maintained in laboratory.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

237 - 270 mg CaCO3/L

Test temperature:

19.2 - 22.4°C

pH:

7.7 - 8.2 measured at the beginning and end of each renewal period

Dissolved oxygen:

84.6 - 94.9 % air saturation measured at the beginning and end of each renewal period

Salinity:

Not applicable

Nominal and measured concentrations:

See Table 1.Results are reported as nominal concentrations

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers
- Type (delete if not applicable): Covered with watch glasses
- Material, size, headspace, fill volume: 100 mL glass beaker filled with 50 mL test medium
- Aeration: None
- Type of flow-through (e.g. peristaltic or proportional diluter): Semi-static, none used
- Renewal rate of test solution (frequency/flow rate): Test medium renewal every 48 or 72 hours
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10
- No. of vessels per vehicle control (replicates): Not applicable
- Biomass loading rate: 50 mL/Daphnia


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Deionisied water
- Total organic carbon: Not reported
- Particulate matter: Not reported
- Metals: Not applicable
- Pesticides: Not applicable
- Chlorine: Not applicable
- Alkalinity: Not applicable
- Ca/mg ratio: Not reported
- Conductivity: Not reported
- Salinity: Not applicable
- Culture medium different from test medium: No
- Intervals of water quality measurement: Not applicable


OTHER TEST CONDITIONS
- Adjustment of pH: None
- Photoperiod: 16L:8D
- Light intensity: 680-800 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Test organisms were observed for parental survival daily. Before renewal of the test media observations made of the numbers of live offspring (observations also made on days 17 and 20). The test units were also checked for signs of other toxic effects. The body length of adults surviving to the end of the test was determined (top of head to base of spina).


VEHICLE CONTROL PERFORMED: Not applicable

- Test concentrations: Nominal concentration 4, 8, 16, 32, 64 mg/L

Reference substance (positive control):

no

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

16 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

37 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: 95% CL: 33 - 40 mg/L

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

body length

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

16 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

body length

Details on results:

- Mortality of parent animals: 0% in controls
- No. of offspring produced per day per female: Mean reproduction rate 104 living offspring per adult in the controls
- Body length and weight of parent animals: Mean body length 4.7 mm in the controls
- Type and number of morphological abnormalities: No abnormalities observed during test
- Type and number of behavioural abnormalities: No abnormalities observed during test
- Time to first brood release or time to hatch: Not reported
- Other biological observations: None reported
- Effect concentrations exceeding solubility of substance in test medium: No

Reported statistics and error estimates:

Statisitical analysis carried out using SAS version 9.1.
For reproductive output: NOEC and LOEC obtained by comparing test item results with the control in two-tailed Dunnett's test with 5% type one error rate. Assumptions of analysis checked using Sharpiro-Wilk's test for normality and Levene's test for homogenity of variance. EC50 obtained by fitting quadratic model (Bailer and Oris 1997), with a 1000 re-sampling bootstrapping technique used to obtain 95% confidence limits.

Table 2: Influence of the test substance on Daphnia magna following exposure for 21 days in a semi-static test

	Control	Nominal concentration (mg/L)
		4	8	16	32	64
Parental mortality after 21 days of exposure (%)	0	0	0	0	0	10
Mean reproduction rate (living offspring per surviving adult)	104	76	131	144	66	0
Mean body length of the adults (mm)	4.7	4.7	4.6	4.6	4.4	4

 

Validity criteria fulfilled:

yes

Remarks:

Control immobility <20%. Dissolved oxygen maintained at >60%. Mean number of offspring per parent in control >60.

Conclusions:

Based on nominal concentrations, the 21-day NOEC and EC50 for the inhibition of the reproduction rate of Daphnia magna were 16 mg/L and 37 mg/L, respectively. The 21-d NOEC for the influence of the test substance on body length of the parental daphnids was 16 mg/L.

Executive summary:

The effect of the test substance on the survival, growth (body length) and reproduction of daphnia magna was determined. This study was run with a dilution water control and with nominal test item concentrations of 4, 8, 16, 32 and 64 mg/L. Based on nominal concentrations, the 21-day NOEC and EC50 for the inhibition of the reproduction rate of daphnia magna were 16 mg/L and 37 mg/L, respectively. The 21-d NOEC for the influence of NMST on body length of the parental daphnids was 16 mg/L.

Description of key information

NOEC=16 mg/L (reproduction and growth body length), 21d, Daphnia magna, semi-static, OECD 211, Ashwell 2005

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

16 mg/L

Additional information

The effect of the test substance on the survival, growth (body length) and reproduction of water flea (Daphnia magna) was determined. This study was run with a dilution water control and with nominal test item concentrations of 4, 8, 16, 32 and 64 mg/L. Based on nominal concentrations, the 21-day NOEC and EC50 for the inhibition of the reproduction rate of water flea (Daphnia magna) were 16 mg/L and 37 mg/L, respectively. The 21-d NOEC for the influence of NMST on body length of the parental daphnids was 16 mg/L. The study is considered to be reliable and adequate for the purposes of risk assessment, classification and labelling.