Sodium O-ethyl dithiocarbonate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction: US EPA accepted QSAR method for chemicals properties assessment.

Qualifier:

according to guideline

Guideline:

other: QSAR

Principles of method if other than guideline:

EPI Suite v 4.0/ECOSARv1.00

GLP compliance:

no

Remarks:

not applicable to QSAR models

Analytical monitoring:

not required

Vehicle:

not specified

Test organisms (species):

other: Daphnid species

Details on test organisms:

no further information

Test type:

other: QSAR model

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 d

Hardness:

not applicable. QSAR model

Test temperature:

not applicable. QSAR model

pH:

not applicable. QSAR model

Dissolved oxygen:

not applicable. QSAR model

Salinity:

not applicable. QSAR model

Details on test conditions:

100% Sodium ethyl xanthate (CAS No. 140-90-9)
SMILES : S=C([S-])OCC.[Na+]
CHEM : Carbonodithioic acid, o-ethyl ester, sodium salt
MOL FOR: C3 H5 O1 S2 Na1
MOL WT : 144.18
Log Kow: 0.87 (used)
Wat Sol: 1.79E+004 mg/L (WskowWin estimate)

Reference substance (positive control):

no

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

43.19 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: cited as a ChV value

Details on results:

Daphnid, 30-day,NOEC for freshwater species cited as ChV (chronic value) =43.190 mg/L (ppm)

Overview of QSARs estimations on long-term aquatic toxicity of  SEX

to Daphnid     

Method	Results	Remarks	Reference
QSAR estimate	Daphnid , 48-hr LC50 = 445.776 mg/L (ppm)   Daphnid, 30-day, ChV (chronic value) = 43.190 mg/L (ppm)	Reliable with restrictions, QSAR estimated data	ECOSAR Program (v1.00)

 

 The ECOSAR QSAR model predicts that NOEC for fresh water species cited as ChV (chronic value) would to be43.190 mg/l therefore that the substance is effectively not toxic to Daphnid.

 

 Daphnid , 48-hr LC50 = 445.776 mg/L (ppm)

 Daphnid, 30-day, ChV (chronic value) = 43.190 mg/L (ppm

 

Validity criteria fulfilled:

yes

Remarks:

US EPA accepted QSAR method for chemicals properties assessment.

Conclusions:

Daphnid, 30-day,NOEC cited as ChV (chronic value) = 43.190 mg/L

Executive summary:

ECOSAR QSAR model predicts that NOEC for fresh water species cited as ChV (chronic value) would to be 43.190 mg/l therefore that the substance is effectively not toxic to Daphnid.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction: US EPA accepted QSAR method for chemicals properties assessment.

Qualifier:

according to guideline

Guideline:

other: QSAR

Principles of method if other than guideline:

EPI Suite v 4.0/ECOSARv1.00

GLP compliance:

no

Remarks:

not applicable to QSAR models

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

other: Mysid shrimp

Details on test organisms:

Scientific name: Americamysis bahia
Common name: Opossum shrimp, Mysid shrimp, Mysids

Test type:

other: QSAR model

Water media type:

saltwater

Limit test:

no

Total exposure duration:

30 d

Hardness:

not applicable. QSAR model

Test temperature:

not applicable. QSAR model

pH:

not applicable. QSAR model

Dissolved oxygen:

not applicable. QSAR model

Salinity:

not applicable. QSAR model

Details on test conditions:

100% Sodium ethyl xanthate (CAS No. 140-90-9)
SMILES : S=C([S-])OCC.[Na+]
CHEM : Carbonodithioic acid, o-ethyl ester, sodium salt
MOL FOR: C3 H5 O1 S2 Na1
MOL WT : 144.18
Log Kow: 0.87 (used)
Wat Sol: 1.79E+004 mg/L (WskowWin estimate)

Reference substance (positive control):

no

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

252.828 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: cited as a ChV value

Details on results:

Mysid Shrimp (SaltWater), 30-day,NOEC cited as ChV (chronic value) = 252.828 mg/L (ppm)

Overview of QSARs estimations on long-term aquatic toxicity of SEX

to Mysid shrimp

Method	Results	Remarks	Reference
QSAR estimate	Mysid Shrimp, 96 -hr, LC50= 2090.966 mg/L (ppm) Mysid Shrimp (SW), 30-day, ChV (chronic value) =  252.828 mg/L (ppm)	Reliable with restrictions, QSAR estimated data	ECOSAR Program (v1.00)

  

Mysid Shrimp, 96 -hr, LC50= 2090.966 mg/L (ppm)

Mysid Shrimp (SW), 30-day, ChV (chronic value) =  252.828 mg/L (ppm)

 

 

Validity criteria fulfilled:

yes

Remarks:

US EPA accepted QSAR method for chemicals properties assessment.

Conclusions:

Mysid Shrimp, 96 -hr, LC50= 2090.966 mg/L (ppm)
Mysid Shrimp (SW), 30-day, ChV (chronic value) =  252.828 mg/L (ppm)

Executive summary:

Using the EPIWIN ECOSAR QSAR model, a 30-day NOEC cited as a ChV  (chronic value) for marine water (SW) aquatic invertebrates of 252.828 mg/L (ppm) was established.

Reference 3

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Ethanol/ Ethyl Alcohol is both reagents used in the manufacture of sodium O-ethyl dithiocarbonate . Therefore, Ethanol/ Ethyl Alcohol need to be considered in the assessment of sodium O-ethyl dithiocarbonate.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Follows the basic methodology for the three brood test proposed by Mount and Norberg (Mount, D.J. and Norberg, T.J. (1984) A seven-day life cycle cladoceran toxicity test. Environ. Toxicol. Chem. 3, 425 - 434). The principle of the test is to assess the effect of the test substance on the reproductive output of ceriodaphnia. The output of the test is a 48hr EC50 and survival at the end of the three broods produced during the test time, total progeny, number of broods, mean brood size and dry weight.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances): no specific measures required (easy substance)

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Daphnia magna
- Source: Daphnia magna strauss 1820 populations (of British origin) had been maintained in the Dow Chemical Company Laboratory since 1982 without drastic changes in population. Population maintained at 25C for previous 3 years and sustained on Ankistrodesmus convulutus (reared in medium based on Provasoli and Pintner (1968, Ecological implications of in vitro nutritional requirements of algal flagellates", Ann NY Acad. Sci. 56, 839-851.) and Nitzschia frustulum Kutzing cultured in ES-I-Si, a medium developed by Provasoli (1968, "Media and prospects for the cultivation of marine algae", in Watanabe A et al, Cultures and collections of algae, Proceedings of a US-Japan conference, Hakone 1966.) Algal diet axenic.
- Age: <12h (all from fourth brood.)
- Feeding rate (cells/vessel): A. convolutes 18x10^6, N. frustulum 3.6 x10^6
- Frequency: daily

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: - Into each jar was fitted a glass tube, 3.5 cm diameter which had affixed to one end a nytex screen of 1000µm mesh. This screen were afixed to the glass tubes with silicone glue. After the screens were glued to the glass tubes, three glass beads, 8 mm in diameter, were affixed to the underside equidistant from each other. This was covered with a glass petal dish 5.5 cm in diameter. The jar containing the screened tube was filled with double distilled water and autoclaved for 10 mins at a pressure of 124 kPa. This procedure was repeated three times, renewing the distilled water each time, before the equipment was used for a test. This procedure accomplished the complete removal of all effects of the silicone glue. Only glass vessels were used. Use of the screened tubes minimises handling and reduces the chance of accidental death.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

10 d

Remarks on exposure duration:

9-11

Hardness:

Dilution water Hardness: 160-180 as mg CaCO3/L

Test temperature:

25 ± 2

pH:

8.2 ± 0.2

Dissolved oxygen:

8.0 ± 1.5mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Test concentrations used: not specified.

Details on test conditions:

The testing conditions followed the basic tenets of the original three-brood test proposed by Mount and Norberg (Environ Toxicol Chem 3, 425-341984) but were revised in that they emphasize the needs of the animals in terms of space and diet. Additional details of the conditions may be found in Cowgill and Milazzo (Bull Environ Contam Toxicol, 42, 749-53, 1989).

TEST SYSTEM
- Test vessel: wide mouth clear glass jars graduated in milliliters to contain 150mL. Into each jar was fitted a glass tube, 3.5 cm diameter. which had affixed to one end a nytex screen of 243 µm mesh for C. dubia or 1000 µm mesh for D. magna, These screens were affixed to the glass tubes with silicone glue. After the screens were glued to the glass tubes, three glass beads, 8 mm in diameter, were affixed to the underside equidistant from each other. This was covered with a glass petal dish 5.5 cm in diameter. The jar containing the screened tube was filled with double distilled water and autoclaved for 10 mins at a pressure of 124 kPa. This procedure was repeated three times, renewing the distilled water each time, before the equipment was used for a test. This procedure accomplished the complete removal of all effects of the silicone glue. Only glass vessels were used.
- Material, size, fill volume: 150ml, 100ml.
- Screen composition: Nytex, Screen mesh size 1000µm
- Habitat: Environmental chamber
- Habitat changing frequency: Every other day
- No. of organisms per vessel: 1
- No. of organisms per concentration: 10
- No. of organisms per control: 20
- Number of control broods: 3
- Screen composition: Nytex
- Screen mesh size, 1000µm
- Permitted control loss, 20%
- Test length, days: 9-11
- Permitted control loss, 20%

TEST MEDIUM / WATER PARAMETERS
TEST MEDIUM / WATER PARAMETERS
- Content 100ml
- Alkalinity: mg CaCQ3/L: 40-52
- Analysis of Lake Huron water used in culturing and testing (ND=not detected with detection limit in brackets):
- Metals: (ug/l): Al 105, Ca 45050 , Cr ND (5), Cu 13, Fe 12, Pb ND (5), Mg 7600, Mn ND (5), K 2485, Na 5700, Zn 15
- Other (ug/l): NH3 total ND(10), B 332, Si 4760, F 75, S 5585.
- Total dissolved solids 233.5mg/l
- Total suspended solids 1725 ug/l
- Total organic carbon 1400 ug/l

OTHER TEST CONDITIONS
- Photoperiod: 16 h light/8 h dark
- Light intensity: 2150 ± 300 lux

EFFECT PARAMETERS MEASURED: Survival, total progeny, dry adult weight, number of broods, mean brood size, loss of control limited to 20% (LC50/EC50/NOEC) Test ended when the control animals had produced three broods.
- Variables monitored Daily: light, temperature, survival, progeny
- Variables monitored every second day: water quality variables in renewed solutions
- Variables monitored at Test termination: Survival, total progeny, adult weight

Duration:

2 d

Dose descriptor:

LC50

Effect conc.:

9 248 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CI: 7560 - 12600

Duration:

9 d

Dose descriptor:

LC50

Effect conc.:

454 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% C: 232 - 814

Duration:

9 d

Dose descriptor:

LC50

Effect conc.:

1 420.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

sodium ethyl xanthate

Basis for effect:

mortality

Remarks on result:

other: On a molecular weight scaled basis, the LC50 would be 1420.9mg/l. (454 x 144.19) /46.07 =1420.9 mg/l

Duration:

9 d

Dose descriptor:

NOEC

Effect conc.:

9.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: same NOEC for adults and offspring

Duration:

9 d

Dose descriptor:

NOEC

Effect conc.:

30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

sodium ethyl xanthate

Basis for effect:

reproduction

Remarks on result:

other: On a molecular weight scaled basis, the NOEC would be 30 mg/l. (9.6 x 144.19) /46.07=30 mg/l

Details on results:

RESULTS FOR CONTROLS:
- Total progeny produced: 1423 +/- 162
-Total progeny/female: 71 +/- 9
- Mean brood size: 22.8 +/-1.6
- Time of first brood: 117 hrs (+/- 9)
- Dry weight of control animals (ug/adult): 647 (+/-76)

Reported statistics and error estimates:

Statistical methods: For LC50: Probit, moving average and nonlinear interpolation. Calculation of point estimates and other corresponding 95% confidence intervals made using a program written by Stephan (1977, Methods for calculating an LC50, In Mayer FL et al (eds), Aquatic toxicology and hazard assessment, ASTM STP 634: 65-84). Calculation of EC50: statistical package SAS GLM (1987, SAS/STAT guide for personal computers, version 6th ed, SAS institute Inc, Cary, NC) used to generate regression equations. NOELs calculated using Dunnett's t-test.

Reproduction NOEC is based on the criteria of total progeny and mean brood size.

Validity criteria fulfilled:

yes

Remarks:

Permitted control loss <20%, production of offspring satisfactory.

Conclusions:

A 9d NOEC of 9.6 mg/L has been determined for the effects of the test substance (Ethyl Alcohol ) on reproduction of the Daphnia magna.
Ethyl Alcohol is both reagents used in the manufacture, as well as decomposition products of xanthates.
On a molecular weight scaled basis, the NOEC would be 30 mg/l. (9.6 x 144.19) /46.07=30 mg/l
On a molecular weight scaled basis, the LC50 would be 1420.9 mg/l. (454 x 144.19) /46.07 =1420.9 mg/l

Executive summary:

In a very well reported invertebrate reproduction study, Daphnia magna were exposed to ethanol over a period of approximately 10 days, sufficient for the production of 3 broods of offspring. An LC50 of 454mg/l was reported for the adults but a much lower NOEC of 9.6mg/l was reported for the reproduction test, based on criteria of total progeny, number of broods and mean brood size.

Synopsis

EC50 (adult, mortality) = 454 mg/l

NOEC (reproduction) = 9.6 mg/l

On a molecular weight scaled basis, the NOEC would be 30 mg/l. (9.6 x 144.19) /46.07=30 mg/l

On a molecular weight scaled basis, the LC50 would be 1420.9 mg/l. (454 x 144.19) /46.07 =1420.9 mg/l

Reference 4

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Ethanol/ Ethyl Alcohol is both reagents used in the manufacture of sodium O-ethyl dithiocarbonate . Therefore, Ethanol/ Ethyl Alcohol need to be considered in the assessment of sodium O-ethyl dithiocarbonate

Qualifier:

no guideline available

Principles of method if other than guideline:

Study to assess the sensitivity of the grass shrimp developmental cycle to the ethanol by exposing embryos from the daggerblade grass shrimp from the tissue cap stage embryo stage (day 3 - late gastrula) through to 2 days post hatch, a total of 12 days exposure, a test that is known as the "Shrimp embryo teratogenesis assay - Palaemonid" or SETAP.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances): no specific measures required (easy substance)

Test organisms (species):

Palaemonetes pugio

Details on test organisms:

TEST ORGANISM
- Common name: daggerblade grass shrimp
- Strain/clone: Palaemonetes pugio
- Source: Adult male and females collected using push nets from a single site in Escambia Bay, Pensacola, FL during Sept 95, Mar and May 96. Salinity during these collections ranged from 3 to 20ppt and temperature from 16.8 to 28.3C.
- Age of parental stock (mean and range, SD):

ACCLIMATION
- Acclimation period: up to 6 months in flow -through (24 ltr/hr) aquaria (80L)
- Acclimation conditions (same as test or not): 19-25C, salinity 22ppt
- Type and amount of food/ Feeding frequency: 2.5g flake food daily and 25ml concentrated A salina nauplii twice/week.
- Health during acclimation (any mortality observed): reproduced freely

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: Gravid females were examined (microscope) for presence of embryos at tissue cap stage (2-3 days after oviposition). Such embryos were removed under a dissecting microscope and the embryos gently removed from female pleopods and separated from other embryos using forceps and fine-tip probes, then transferred to the well plates containing the test solutions.

Test type:

not specified

Water media type:

saltwater

Limit test:

no

Total exposure duration:

12 d

Hardness:

NR

Test temperature:

NR

pH:

NR

Salinity:

not applicable

Nominal and measured concentrations:

Five different dilutions used - 0.05, 0.10, 0.50, 1.0 and 2.0% v/v%). Dilutions were made with histological grade 100% EtOH and 20 ppt 0.22 pm filtered natural sea water. Filtered sea water was also used as control.

Details on test conditions:

TEST SYSTEM
- Test vessel: disposable 24-well flat bottom plastic culture plates, with one animal per well.
- fill volume: 2ml
- Method: Plates were placed on rotators in an incubator maintained at 27C±1 for 12 days. Rotators were set at 60 rpm to provide a gentle agitation of the embryos in the test wells. After a 12-d exposure, embryos were examined for mortality.

Reference substance (positive control):

no

Duration:

12 d

Dose descriptor:

LC50

Effect conc.:

530 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

of embryos

Remarks on result:

other: Coefficient of variaion = 37%

Duration:

12 d

Dose descriptor:

LC50

Effect conc.:

1 658.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

sodium ethyl xanthate

Basis for effect:

mortality

Remarks:

of embryos

Remarks on result:

other: On a molecular weight scaled basis, the LC50 would be 1658.8 mg/l. (530 x 144.19) /46.07 =1658.8 mg/l

Details on results:

Range of values 0.05 to 0.91. (based on 11 repetitions carried out with 0.37% to 1.10% v/v ethanol and with range of animal 'ages' where 'age' is the length of time in laboratory culture since collection. Ages vary from 1 day to 160 days with no clear correlation between the age and the resultant LC50 although there was some evidence that embryos oviposited in the field had greater sensitivity (2-10x) than those ovipositied in the laboratory.

It should be noted that mortality was high in controls in three of the studies. Two of these accounted for the two lowest values, which if excluded would mean that the range of results was 0.26 to 0.91g/l. The authors of the study noted the high mortality but attributed it to canibalism.

Reported statistics and error estimates:

12-d LC5O values and 95% confidence intervals (Cl) were calculated using the trimmed Spearman- Karber method (Hamilton et al. 1977). Average of mean 1 2-d LC5O values and coefficients of variation (CV) were calculated according to Steel and Torrie (1980).

Average control mortality 11.7% with a standard error of 3.2%. Three results showed mortalities over 16.7%. One results produced a very low value (order of magnitude lower). High control mortality was observed and it was not possible to calculate an LC50. The average value from the remainder was an LC50 value 0.53% (4.18g/l) SD=0.20% (1.58g/l).

Validity criteria fulfilled:

not applicable

Remarks:

no validation criteria available.

Conclusions:

Ethanol is practically non-toxic to invertebrate embryos over a reproduction cycle.
Ethyl Alcohol is both reagents used in the manufacture, as well as decomposition products of xanthates.
On a molecular weight scaled basis, the LC50 would be 1658.8 mg/l. (530 x 144.19) /46.07 =1658.8 mg/l

Executive summary:

In a study to assess the sensitivity of the grass shrimp developing embryos to ethanol, embryos from the daggerblade grass shrimp were exposed to the test substance from the tissue cap stage embryo stage (day 3 - late gastrula) through to 2 days post hatch, a total of 12 days exposure in a test known as the "Shrimp embryo teratogenesis assay - Palaemonid" or SETAP. The LC50 obtained based for embryo mortality was 0.53g/l, which suggests that ethanol is practically non-toxic to invertebrate embryos.

Synopsis

LC50 (invertebrate embryo lethality) = 0.53g/l

Ethyl Alcohol is both reagents used in the manufacture, as well as decomposition products of xanthates.

On a molecular weight scaled basis, the LC50 would be 1658.8 mg/l. (530 x 144.19) /46.07 =1658.8 mg/l

Reference 5

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Ethanol/ Ethyl Alcohol is both reagents used in the manufacture of sodium O-ethyl dithiocarbonate . Therefore, Ethanol/ Ethyl Alcohol need to be considered in the assessment of sodium O-ethyl dithiocarbonate

Qualifier:

no guideline available

Principles of method if other than guideline:

Study to assess the sensitivity of the grass shrimp developmental cycle to the ethanol by exposing embryos from the daggerblade grass shrimp from the tissue cap stage embryo stage (day 3 - late gastrula) through to 2 days post hatch, a total of 12 days exposure, a test that is known as the "Shrimp embryo teratogenesis assay - Palaemonid" or SETAP.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

no

Test organisms (species):

Palaemonetes pugio

Details on test organisms:

TEST ORGANISM
- Common name: daggerblade grass shrimp
- Strain/clone: Palaemonetes pugio
- Justification for species: because of its widespread presence in East Coast American estuaries and importance in the food chain for fish.
- Source: Collected by dip netting in spring and autumn 1995 from uncontaminated estuaries near Gulf Breeze, Florida. The grass shrimp were placed in ice chests with water from the collection site, transported to the laboratory.
- Age of parental stock (mean and range, SD):
- Feeding during test: no data

ACCLIMATION
- Acclimation period: slowly acclimated to 25C and 20ppt salinity over a 4 hour period then held for 2 weeks.
- Acclimation conditions (same as test or not): 25C, 20ppt salinity
- Type and amount of food: no data

QUARANTINE (wild caught)
- Duration: 2 weeks
- Health/mortality: found to reproduce freely

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: Gravid females were examined (microscope) for presence of embryos at tissue cap stage (2-3 days after oviposition). Such embryos were removed under a dissecting microscope and the embryos gently removed from female pleopods and separated from other embryos using forceps and fine-tip probes, then washed 3x in 20ppt filtered seawater.

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

12 d

Hardness:

NR

Test temperature:

27 +/-1C

pH:

NR

Salinity:

20 ppt

Nominal and measured concentrations:

Treatment concentrations: 0.079, 0.39, 0.79, 1.97, 3.95, 7.9 g/l.

Details on test conditions:

TEST SYSTEM
- Test vessel: 24 well plastic tissue culture plates, placed in an incubator at 27C and place on a rotary shaker at 60rpm
- Test volume: 2mls.
- Procedure: Each well contained a single embryo. Embryos were checked daily for abnormalities (eye, yolk, heart, head, hepatopancreas, telson.
- No. of vessels per concentration (replicates): 3
- No. of test concentrations used: 5-6 (not specified)

EFFECT PARAMETERS MEASURED: Both the number and type of abnormality were recorded. Survival was determined by structural integrity of the embryo during the first four days of the test, and thereafter by the presence or absence of heartbeat. Mortalities and hatching were recorded daily. Exposures were terminated after 12 d(14--l5 d after oviposition).

Reference substance (positive control):

no

Duration:

12 d

Dose descriptor:

NOEC

Effect conc.:

79 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: developmental delay

Duration:

12 d

Dose descriptor:

LOEC

Effect conc.:

390 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: developmental delay

Duration:

12 d

Dose descriptor:

LC50

Effect conc.:

3.63 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: coefficient of variation = 21.9%

Duration:

12 d

Dose descriptor:

NOEC

Effect conc.:

247.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

sodium ethyl xanthate

Basis for effect:

other: developmental delay

Remarks on result:

other: On a molecular weight scaled basis, the NOEC would be 247.3 mg/l. (79x 144.19) /46.07 =247.3 mg/l

Details on results:

LC50 values with 95% confidence intervals and coefficients of variation were calculated from total mortalities.

Reported statistics and error estimates:

Statistical analysis: LC50s with confidence intervals were calculated by Litchfield-Wilcoxon probit analysis.

The dose response of the mortality curve was quite shallow with mortalities of >30% at 0.39g/l but <70% at 8g/l (from the experimental data). Developmental abnormalities were not noted at the 0.079g/l concentration but were seen at 0.39 and 0.79g/l and resulted in delayed hatching. Two embryos failed to hatch properly and had swimming difficulties as larvae. Malformations were detected in 21.7% of the embryos exposed to the 3 lowest concentrations and most of the malformed embryos died before the end of the assay. Developmental delay was detected 6 days after oviposition at the three higher concentrations. By 9 days nearly all the embryos exposed to the highest concentration died before the end of the assay and all embryos that died were malformed before the died. Only the 1.97g/l treatments had larvae that survived with malformations.

The overall; control mortality was 7.4% (16/216).

Validity criteria fulfilled:

not applicable

Remarks:

no validation criteria for the assay

Conclusions:

Ethanol is practically non-toxic to invertebrate embryos over a reproduction cycle.
Ethyl Alcohol is both reagents used in the manufacture, as well as decomposition products of xanthates.
On a molecular weight scaled basis, the NOEC would be 247.3 mg/l. (79x 144.19) /46.07 =247.3 mg/l

Executive summary:

In a study to assess the sensitivity of the grass shrimp developing embryos to ethanol, embryos from the daggerblade grass shrimp were exposed to the test substance from the tissue cap stage embryo stage (day 3 - late gastrula) through to 2 days post hatch, a total of 12 days exposure in a test known as the "Shrimp embryo teratogenesis assay - Palaemonid" or SETAP. The LC50 obtained based on mortality was 3.63g/l, which suggests that ethanol is not acutely toxic to invertebrate embryos. However, the NOEC based on developmental toxicity, in this case developmental delay, was 79mg/l.

Synopsis

LC50 (invertebrate embryo lethality) = 3.63g/l

NOEC (developmental effects) = 79mg/l

On a molecular weight scaled basis, the NOEC would be 247.3 mg/l. (79x 144.19) /46.07 =247.3 mg/l

Description of key information

ECOSAR QSAR model predicts that NOEC for fresh water species cited as ChV (chronic value) would to be 43.190 mg/l therefore that the substance is effectively not toxic to Daphnid.
Using the EPIWIN ECOSAR QSAR model, a 30-day NOEC cited as a ChV  (chronic value) for marine water (SW) aquatic invertebrates of 252.828 mg/L (ppm) was established.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

43.19 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

252.828 mg/L

Additional information

ECOSAR QSAR model predicts that NOEC for fresh water species cited as ChV (chronic value) would to be 43.190 mg/l therefore that the substance is effectively not toxic to Daphnid.

Using the EPIWIN ECOSAR QSAR model, a 30-day NOEC cited as a ChV  (chronic value) for marine water (SW) aquatic invertebrates of 252.828 mg/L (ppm) was established.