long chain alkyl thio carbamide metal complex

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

Study period:

19-Jun-2002 to 28-Jun-2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: OECD Series on Testing and Assessment. No. 23. Guidance document on aquatic toxicity testing of difficult substances and mixtures

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Remarks:

Total Organic Carbon (TOC) analysis

Details on sampling:

- Concentrations: Nominally 0, 42, 93, 203, 452, 1002 mg/litre
- Sampling method: samples were taken from the water-accommodated fractions (WAFs) and control solution on Day 0 and on a composite of the replicates at termination (Day 2). Samples were taken with no headspace in 40 ml volatile organic analysis vials.
- Sample storage conditions before analysis: no data

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Individual treatments were prepared by adding the appropriate amount of test substance to 2.0 litres of laboratory dilution water in glass aspirator bottles. The test substance is a viscous liquid. The appropriate amount of the substance was weighed onto Teflon@ discs prior to water-accommodated fraction (WAF) preparation. The WAFs were prepared by adding the disc and test substance to reconstituted water in glass aspirator bottles and stirring on magnetic stir-plates at
- Controls: Four replicates of the control were prepared in the same manner using reconstituted water.

- Evidence of undissolved material (e.g. precipitate, surface film, etc): During mixing, the treatments appeared clear / colourless with the test substance on the discs at the bottom of the mixing vessels. After stirring, the mixtures were allowed to settle for 4 hours in a water bath at 20.9 ºC, before the aqueous portions were removed through the outlet at the bottom of the vessels. After stirring the mixtures appeared clear / colorless with the test substance on the discs at the bottom of the mixing vessels.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain: Strauss
- Source: Cultured at the test facility; original culture supplied by Aquatic Biosystems, Inc.; starter culture received l l-Apr-2002
- Age at study initiation (mean and range, SD): <24 hours old, taken from 14-day old parents
- Feeding during test: not fed

ACCLIMATION
- not applicable (neonates used for study)

QUARANTINE (wild caught)
- not applicable (cultured at test facility)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

none

Hardness:

202 mg CaCO3/litre

Test temperature:

20.7-20.9ºC

pH:

6.9-7.4

Dissolved oxygen:

8.5

Salinity:

not applicable

Nominal and measured concentrations:

Nominal: 0, 42, 93, 203, 452, 1002 mg/litre
Due to the complex nature of the test substance, samples of the water-accommodated fractions (WAFs) were analyzed for Total Organic Carbon (TOC) content: 0.23, 0.22, 0.25, 0.24, 0.25 and 0.35 mg/litre

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flask
- Type (delete if not applicable): closed with a ground glass stopper
- Material, size, headspace, fill volume: glass, 125 ml size, no headspace, 140 ml volume of solution
- Aeration: dilution water was aerated prior to the addition of the test substance
- Type of flow-through (e.g. peristaltic or proportional diluter): static
- Renewal rate of test solution (frequency/flow rate): not renewed
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): no vehicle
- Biomass loading rate: 28 ml solution/daphnid

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted Water (Batch 120A). The dilution water is prepared from UV-sterilized, deionized well water that is treated and distributed throughout the testing facility via PVC and stainless-steel pipes
- Total organic carbon: <1.0 ppm
- Particulate matter, Metals, Pesticides, Chlorine: no known contaminants in the feed used in culturing the organisms or the dilution water believed to be at levels high enough to interfere with this study
- Alkalinity: 32 mg/litre (as CaCO3)
- Ca/mg ratio: 2.8: 1
- Na/K ratio: 5.9: 1
- Conductivity: 520 µmhos (specific conductance)
- Culture medium different from test medium: no
- Intervals of water quality measurement: no data

OTHER TEST CONDITIONS
- Adjustment of pH: no data
- Photoperiod: 16 hours light, 8 hours dark
- Light intensity: 191-213 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : observations of immobilisation at 24 and 48 hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.2
- Justification for using less concentrations than requested by guideline: study in accordance with guideline

RANGE FINDING STUDY
- Test concentrations: nominally 0, 10, 100 mg/litre
- Results used to determine the conditions for the definitive study: no data

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confidence interval 38-62 mg/L; water accommodated fraction tested; concentration expressed as loading rate

Key result

Duration:

48 h

Dose descriptor:

LOELR

Effect conc.:

42 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: lowest concentration tested; water accommodated fraction tested; concentration expressed as loading rate

Details on results:

- Behavioural abnormalities: none reported
- Other biological observations: % survival in 0, 42, 93, 203, 452 and 1002 mg/litre treatments:
- at 24 hours: 100, 100, 100, 95, 90, 85
- at 48 hours: 100, 60, 5, 0, 0, 0
- Mortality of control: 0
- Other adverse effects control: none
- Abnormal responses: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: after stirring the mixtures appeared clear / colourless with the test substance on the discs at the bottom of the mixing vessels
- Effect concentrations exceeding solubility of substance in test medium: no data

Results with reference substance (positive control):

none

Reported statistics and error estimates:

maximum likelihood analysis

Validity criteria fulfilled:

yes

Conclusions:

In a GLP study conducted according to OECD guideline 202 (and OECD guidance document 23), an acute 48-h EL50 of 50 mg/litre (nominal) and an 48-h LOELR of 42 mg/litre (nominal) were determined for EC# 457-320-2 in Daphnia magna. The lowest concentration causing 100% immobilisation was 203 mg/litre (nominal). Effect concentrations were based on loading rates as there were no data on the measured mass of test material in the WAFs.

Executive summary:

In a GLP study conducted according to OECD guideline 202 and OECD guidance document 23, Daphnia magna were exposed to nominal concentrations of EC#457-320-2 of 0, 42, 93, 203, 452 and 1002 mg/litre. The test material was poorly soluble in water and its toxicity was determined by preparing water-accommodated fractions (WAFs). Test mixtures were prepared by placing the appropriate amount of test material onto Teflon discs and placing in glass bottles containing 2 litres of dilution water. After stirring for 41 h and settling for 4 h, the clear/colourless aqueous portions (WAFs) were removed for use in the test, with some test material (apparently not quantified) remaining on the discs at the bottom of the mixing vessels. In the absence of a suitable analytical method, test mixtures were analysed for total organic carbon (TOC), but not for test material. Groups of 20 daphnids/concentration were observed at 24 and 48 h for immobilisation. The Daphnia were not fed during the study.

The 24-h EL50 could not be calculated since only 15% immobilisation was seen at the highest concentration. Based on nominal concentrations, the 48-h EL50 was 50 mg/litre (95% confidence interval 38 to 62 mg/litre) and the 48-h LOELR was 42 mg/litre (nominal). The lowest concentration causing 100% immobilisation was 203 mg/litre. TOC concentrations were similar in all test mixtures and the control (0.2-0.3 mg/litre).

In conclusion, an acute 48-h EL50 of 50 mg/litre (nominal) and an 48-h LOELR of 42 mg/litre (nominal) were determined for EC# 457-320-2 in Daphnia magna. Effect concentrations were based on loading rates as there were no data on the measured mass of test material in the WAFs.

Description of key information

The 48-hour EL50 for Daphnia was 50 mg/L (nominal loading rate)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

50 mg/L

Additional information

One study of the short-term toxicity of EC# 457-320-2 to aquatic invertebrates is available: an acute Daphnia study conducted to GLP and in accordance with OECD Test Guideline 202. Due to the poor water solubility of the test substance, test waters were prepared as Water Accommodated Fractions (WAFs) of nominal loading rates of 0, 42, 93, 203, 452 and 1,000 mg/L. In the absence of a suitable analytical method, test mixtures were analysed for total organic carbon (TOC), but not for test material.

The 48-h EL50 was 50 mg/litre (95% confidence interval 38 to 62 mg/litre); the 48-h LOELR was 42 mg/litre (nominal). The lowest concentration causing 100% immobilisation was 203 mg/litre. TOC concentrations were similar in all test mixtures and the control (0.2-0.3 mg/litre).