Carbamic acid, N-[(butylthio)thioxomethyl]-, butyl ester

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 July - 7 August 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Also in accordance with GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

(2004)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

(2008)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: ISO International Standard 6341: "Water quality - Determination of the inhibition of the mobility of Daphnia magna Straus - Acute toxicity test, Third edition (1996)

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23 (2000)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

butyl N-[(butylsulfanyl)methanethioyl]carbamate

EC Number:

691-061-8

Cas Number:

1001320-38-2

Molecular formula:

C10H19NO2S2

IUPAC Name:

butyl N-[(butylsulfanyl)methanethioyl]carbamate

Test material form:

solid

Remarks:

yellow grease-like solid

Specific details on test material used for the study:

Molecular formula: C10H19NO2S2
Name: n-butoxycarbonyl n-butyl dithiocarbamate (active ingredient)
CAS Number: 1001320-38-2

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations
Combined limit/range finding test: 1, 10 and 100 mg/L water accommodated fractions (WAFs)
Final test: blank control, 0.46, 1.0, 2.2, 4.6 and 10 mg/L WAFs
- Sampling method
Frequency: at t=0 h and t=48 h
Volume: 2.0 mL
- Sample storage conditions before analysis: Samples not analysed on the day of sampling were stored in a freezer until analysis.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance was warmed to approximately 28°C in order to melt. The liquid test substance was used for weighing out the required amounts of test substance. All loading rates were prepared separately applying one day of magnetic stirring to reach maximum solubility of the test substance in the test medium. The resulting aqueous mixtures were left to stabilize for 30-60 minutes where after the Water Accommodated Fractions (WAFs) were taken out by siphoning. No correction was made for the purity/composition of the test substance.
- Controls: Test medium without test substance or other additives
- Evidence of undissolved material (e.g. precipitate, surface film, etc): Test concentrations prepared for the combined limit range-finding test were observed to range from clear and colourless to slightly hazy with a floating layer with increasing loading rate. Test concentrations prepared for the final test were observed to be clear and colourless.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Source: In-house laboratory culture with a known history
- Age at study initiation: <24 h
- Feeding during test: None

BREEDING:
- Method: At least third generation obtained by acyclical parthenogenesis under specified breeding conditions. Each batch started with newborn daphnids (i.e. less than three days old) and the maximum age of the cultures was 4 weeks
- Conditions (same as test or not): yes
- Type of food: suspension of fresh water algae
- Feeding frequency: Daily
- Health during acclimation (any mortality observed): Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

180 mg/L expressed as CaCO3

Test temperature:

The temperature of the test medium ranged between 20.2 and 21.1°C at the start of the test. The temperature continuously measured in a temperature control vessel varied between 19.3 and 20.0°C during the test.

pH:

Start: 7.8-7.9
End: 7.7-7.8

Dissolved oxygen:

Start: 8.3-8.8 mg/L
End: 8.4-8.6 mg/L

Nominal and measured concentrations:

Nominal: Blank control, WAFs prepared at loading rates of 0.46, 1.0, 2.2, 4.6 and 10 mg/L

Details on test conditions:

TEST SYSTEM (final test)
- Test vessel: all glass with 100 mL capacity containing 80 mL of test solution. Vessels were fitted with a mesh just under the medium surface to separate the dahnids from possible floating layers.
- Aeration: None
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Loading: 5 daphnids per 80 mL of test solution

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water purified by Reverse Osmosis
- Culture medium different from test medium: Yes (M7 medium prepared with adjusted ISO medium)
- Test medium: adjusted ISO medium
- Intervals of water quality measurement: pH was measured at the beginning of the test and at the end for the control and all test concentrations. Dissolved oxygen was measured at the beginning and at the end of the test for the control and all test concentrations. Temperature was measured continuously in a temperature control vessel.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 h light : 8 h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Immobility (including mortality) at 24 and 48 h.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: approximately x2
- Range finding study
- Test concentrations: blank control and WAFs prepared at a loading rate of 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.42 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: (95% CL: 0.37-0.50 mg/L)

Details on results:

- Combined limit/range-finding test: After 24 hours of exposure all daphnids exposed to the WAFs prepared at 10 and 100 mg/L were immobilised. At the end of the test 60% of the daphnids exposed to the WAFs prepared at 1.0 mg/L were immobilised as well.

- Final test
Measured concentrations: Concentrations did not remain stable during the test period, i.e. they decreased to 46-74% of initial at the end of the test. Consequently, effect parameters were based on mean exposure concentrations.
Biological results: After 48 hours of exposure no immobility was observed at a mean concentration of 0.23 mg/L, while 90% or more immobilisation was observed at mean concentrations of 0.61 mg/L and higher.

Results with reference substance (positive control):

- Potassium dichromate: The 48h-EC50 was 0.30 mg/L (95% confidence level between 0.26 and 0.34 mg/L). The sensitivity of this batch of D. magna was within the range of the historical data collected at WIL Research Europe.

Any other information on results incl. tables

Measured concentrations versus loading rates
Loading rate^1S-10903 (mg/L)	Measured concentration (mg/L)		Mean conc. (mg/L)
	t=0 h	t=48 h
0.46	0.337	0.154	0.23
1	0.806	0.458	0.61
2.2	2.02	1.3	1.6
4.6	3.14	1.97	2.5
10	7.45	5.51	6.4
^1WAF prepared at the given loading rate

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48h-EC50 was 0.42 mg/L (95% confidence level between 0.37 and 0.50 mg/L).

Executive summary:

In a 48-h acute toxicity study conducted according to OECD guideline 202 and GLP principles, water fleas (Daphia magna) were exposed to the test material under static conditions at the following nominal concentrations (final test): 0 (blank-control), WAFs prepared at loading rates of 0.46, 1.0, 2.2, 4.6 and 10 mg/L. The 48h-EC50 was 0.42 mg/L based on average exposure concentrations (95% confidence level between 0.37 and 0.50 mg/L). The study is considered to be reliable without restrictions.