N-ethyl-N-methylcarbamoyl chloride

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

Results are based on nominal concentrations. However, recovery was 77 and 74% (< 80%)

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

yes

Remarks:

Results are based on nominal concentrations. However, recovery was 77 and 74% (< 80%)

GLP compliance:

yes

Specific details on test material used for the study:

- Name of test material (as cited in study report): EMCA
- Physical state: Colourless liquid
- Analytical purity: 99.3 %

Analytical monitoring:

yes

Remarks:

Due to the nature of the test item, a TOC analysis was performed.

Details on sampling:

The test subtance is extremely unstable in water and immediatly decomposes into ethylmethyl carbamic acid. An analytical method using LC-MS was attempted in several conditions i.e. basic/acidic/neutral, organic/aqueous, APCI/ESI, positive/negative but it was not possible to develop such analytical method. Therefore a total organic carbon (TOC) analysis was used as a surrogate measurement.

- Concentrations: 100 mg/L and control at time = 0 and t=48 hours, at the end of the exposure period the replicates were pooled at each concentrations before sampling.
- Sampling method: 40mL from the approximate centre of the test vessels.
- Sample storage conditions before analysis: samples were stored in refrigerator until analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 23-minutes of magnetic stirring was used to prepare the solution of 100 mg/L. The lower test concentrations were prepared by subsequent dilutions in test medium.
- Controls: Test medium.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): No, the test solutions were all clear and colourless.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: In house laboratory culture with known history.
- Age at study initiation (mean and range, SD): less than 24 hours old from parental daphnids of more than two weeks old.
- Method of breeding: The start of each batch was performed with newborn daphnids i.e. less than 3 days old by placin about 250 of them into 5 litres of medium in a all-glass culture vessel, the maximum age of the cultures was 4 weeks old.
- Feeding during test: No

ACCLIMATION
- Acclimation period: Since the daphnids were cultured in the same conditions as for the main test, an additional acclimatisation was no necessary.
- Acclimation conditions (same as test or not): yes
- Type and amount of food: Fresh water algae
- Feeding frequency: Daily
- Health during acclimation (any mortality observed): Mortality < 20 %.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

180 mg/L expressed as CaCO3

Test temperature:

19.0-20.4ºC

pH:

6.5-7.8

Dissolved oxygen:

9.3-9.1 mg/L

Nominal and measured concentrations:

Nominal concentrations: 0.1, 1.0, 10.0 and 100.0 mg/L
Measured concentrations: see table 2 in 'any other information on results'. The results of the TOC analysis of the samples taken from the highest test concentration and control showed that recoveries for the organic carbon were of 77 % at the start and 74 % after 48 hours of exposure, based on theoretical value (39 % carbon content, based on structural formula).

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL all-glass vessels.
- Type (delete if not applicable): open / closed
- Aeration: No aeration of the test solutions.
- No. of organisms per vessel: 5 per vessel containing 80 mL of test solution.
- No. of vessels per concentration (replicates): 2 replicates in 0.1 , 1.0 and 10.0 mg/L concentrations and 4 in the 100 mg/L concentration.
- No. of vessels per control (replicates): 4
- Biomass loading rate: 5 per vessel containing 80 mL of test solution.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap water purified by reverse osmosis "RO-water".
- Culture medium different from test medium: no.
- An adjusted ISO medium was used. Composition: 211.5 mg/L CaCl2*2H2O, 88.8 mg/L MgSO4*7H2O, 46.7 mg/L NaHCO3, 4.2 mg/L KCl.
- The following trace elements, macro nutrients and vitamins were added to freshly prepared ISO medium: 0.125mg/L B, 0.05 mg/L Fe, 0.025mg/L Mn, 0.0125 mg/L Li, Rb and Sr, 0.0063 mg/L Mo, 0.0025 mg/L Br, 0.0016 mg/L Cu, 0.0063 mg/L Zn, 0.0025 mg/L Co and I, 0.0010 mg/L Se, 0.0003 mg/L V, 2.5 mg/L Na2EDTA*2H2O, 10.0 mg/L Na2SiO3*9H2O, 0.27 mg/L NaNO3, 0.14 mg/L KH2PO4, 0.18 mg/L K2HPO4, 75 µg/L Thiamine, 1.0 µg/L B12, 0.75 µg/L Biotin.

OTHER TEST CONDITIONS
- Adjustment of pH: No (7.7 ± 0.3).
- Photoperiod: 16 hours light daily.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobilisation at 24 and 48 hours.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7)

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

dissolved

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: No
- Observations on body length and weight: No
- Mortality of control: No daphnids were immobilized.

Results with reference substance (positive control):

- Results with reference substance valid= yes
- Mortality: 100 %
- 48h-EC50: 0.51 mg/L

Table 1. Acute immobilisation of daphnids after 24 and 48 hours.

EMCA Nominal Concentration (mg/l)	Vessel number	Number Daphnia exposed	Response at 24 h		Response at 48 h
			Number	Total %	Number	Total %
Control	A B C D	5 5 5 5	0 0 0 0	0	0 0 0 0	0
0.1	A B	5 5	0 0	0	0 0	0
1.0	A B	5 5	0 (4) 0	0	0 (2) 0	0
10	A B	5 5	0 0	0	0 0	0
100	A B C D	5 5 5 5	0 (1) 0 (3) 0 0 (1)	0	0 0 0 0	0

* () between brackets: number of daphnia observed trapped at the surface of the test solutions. These organisms were reimmersed into the respective solutions before recording of mobility.

No daphnia was immobilized in all the test item vessels and negative control vessels.

 

Table 2. Measured concentrations.

Time of sampling (h)	Sampling date	TOC analysis date	Nominal concentration (mg/l)	Nominal organic carbon conc. (mg/l)	Measured organic carbon conc. (mg/l)	Recovery relative to nominal (%)
0	11/02/2008	26/02/2008	0 100	0 39	1.4 29.9	- 77
48	13/02/2008	26/02/2008	0 100	0 39	1.2 29.0	- 74

 

Table 3. Measured pH and oxygen concentrations.

EMCA Nominal Concentration (mg/l)	Start (t = 0 h)		End (t = 48 h)
	pH	O2	pH	O2
Control	7.7	9.4	7.8	9.1
100	6.5	9.3	7.8	9.2

 

The pH of the 100 mg/L solution increased by >1 unit during test, however, the pH was mantained within the optimum limits for testing with daphnia magna.

The temperature of the test medium was 20.9 at the start of the test and varied between 19.0 and 20.4 during test.

Validity criteria fulfilled:

yes

Remarks:

The oxygen concentration at the end of the test was ≥ 3 mg/L in the control and test vessels. In the control, no daphnids became immobilised or trapped at the surface of the water.

Conclusions:

The test item did not induce acute immobilisation of Daphnia Magna at nominal concentration of 100 mg/L after 48 hours of exposure. The 48 h-NOEC for the test item was 100 mg/L.

Executive summary:

An acute immobilisation study with daphnia magna was conducted with the test item according to the OECD 202 under GLP conditions. A combined limit/range-finding test was performed. Twenty daphnia (five daphnids per vessel, four vessels) were exposed to control medium or 100 mg/L of the test item in medium for 48 hours under static conditions. In addition, ten daphnia (five daphnids per vessel, two vessels) were exposed to 0.1, 1 or 10 mg/L of test item. pH, temperature and oxygen concentrations were measured. Due to the highly reactive nature of the test item with water, a conventional chromatography-based method for the analytical determination of the concentration was not possible, so a TOC analysis was used as a surrogate. The test substance did not induce acute immobilisation of Daphnia magna at nominal concentration of 100 mg/L after 48 hours of exposure. The 48 h-NOEC was defined as 100 mg/L and the 48h-EC50 as >100 mg/L.

Description of key information

Key study: Test method OECD 202. GLP study. The 48 hours EC50 value for the test item in Daphnia magna was > 100 mg/L and the NOEC was 100 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

Key study: An acute immobilisation study with daphnia magna was conducted with the test item according to the OECD 202 under GLP conditions. A combined limit/range-finding test was performed. Twenty daphnia (five daphnids per vessel, four vessels) were exposed to control medium or 100 mg/L of the test item in medium for 48 hours under static conditions. In addition, ten daphnia (five daphnids per vessel, two vessels) were exposed to 0.1, 1 or 10 mg/L of test item. pH, temperature and oxygen concentrations were measured. Due to the highly reactive nature of the test item with water, a conventional chromatography-based method for the analytical determination of the concentration was not possible, so a TOC analysis was used as a surrogate. The test substance did not induce acute immobilisation of Daphnia magna at nominal concentration of 100 mg/L after 48 hours of exposure. The 48 h-NOEC was defined as 100 mg/L and the 48h-EC50 as >100 mg/L.