Diantimony trioxide

Toxicity to soil macroorganisms except arthropods

Administrative data

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2002-10-28 to 2003-01-27

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: validity criteria not fulfilled, confounding effect of pH decrease on Sb toxicity

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Antimony trichloride

EC Number:

233-047-2

EC Name:

Antimony trichloride

Cas Number:

10025-91-9

Molecular formula:

SbCl3

IUPAC Name:

antimony(3+) trichloride

Test material form:

not specified

Sampling and analysis

Analytical monitoring:

yes

Test substrate

Details on preparation and application of test substrate:

- suitable amount of artificial soil was thoroughly mixed with the appropriate amount of SbCl3 dissolved in a small amount of deionized water
- final water content: 50% of maximum water holding capacity
- equilibrated for 1 week under conditions of temperature and light used during the test

Test organisms

Test organisms (species):

Enchytraeus albidus

Animal group:

annelids

Details on test organisms:

- Source: test organisms originate from culture held at Laboratory for Environmental Toxicology since 1995
- Age at test initiation (mean and range, SD): adults with a fully developed clitellum are used for the tests

Study design

Study type:

laboratory study

Substrate type:

artificial soil

Total exposure duration:

42 d

Test conditions

Test temperature:

20 +/- 1 °C

pH:

6.5 - 3.2 (decreasing pH with increasing SbCl3 dose)

Moisture:

soil kept at 50% of max water holding capacity

Details on test conditions:

TEST SYSTEM
- Test container (material, size):100 ml glass vessels
- Amount of soil or substrate: 20 g
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 4


SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Composition (if artificial substrate): 10% sphagnum peat, 20% kaolin clay, 70ù sand (<200µm), CaCO3 added to adjust pH to 6.0 +/- 0.5

OTHER TEST CONDITIONS
- Photoperiod: 16h:8h light:dark
- Light intensity: 400-800 lux
- feeding: rolled oats, once a week on top of the soil


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- after 21 days, adult enchytraeids are removed and counted. an organism is considered dead if no movement or reaction is observed to a mechanical stimulus
- after 42 days, the soils are submersed with ethanol and Bengal red solution is added in order to facilitate counting of the juveniles. After coloration, the soil is sieved and juveniles are counted.


TEST CONCENTRATIONS
- Spacing factor for test concentrations: factor 3
- Range finding study
- Test concentrations: 1, 10, 100, 1000 and 10000 mg Sb/kg
- Results used to determine the conditions for the definitive study: acute 14d LC50 situated between 1000 and 10000 mg Sb/kg (nominal values). nominal acute 14d NOEC was 1000 mg Sb/kg (measured value: 634 mg Sb/kg dw)

Nominal and measured concentrations:

nominal: control, 100, 320, 1000, 3200 and 10000 mg Sb/kg dw
measured: 0.37, 59.1, 223, 760, 2012 and 6980 mg Sb/kg dw

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

760 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Sb

Basis for effect:

mortality

Effect concentrations 2

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

2 012 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Sb

Basis for effect:

mortality

Remarks on result:

other: 100% effect

Effect concentrations 3

Duration:

42 d

Dose descriptor:

NOEC

Effect conc.:

760 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Sb

Basis for effect:

mortality

Effect concentrations 4

Duration:

42 d

Dose descriptor:

LOEC

Effect conc.:

2 012 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Sb

Basis for effect:

mortality

Remarks on result:

other: 100% effect

Effect concentrations 5

Duration:

42 d

Dose descriptor:

NOEC

Effect conc.:

760 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Sb

Basis for effect:

reproduction

Effect concentrations 6

Duration:

42 d

Dose descriptor:

LOEC

Effect conc.:

2 012 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Sb

Basis for effect:

reproduction

Remarks on result:

other: 100% effect

Details on results:

- average mortality in control soil after 42 days: 5%
- average reproduction in control soil after 42 days: 298 juveniles/replicate (coëfficient of variation = 81 %)

Reported statistics and error estimates:

EC50s will be determined for the different organisms and endpoints, using appropriate logistic dose-response models. Data for percentage survival are arcsine square root transformed and then tested for normality and homoscedasticity using the Kolmogorov-Smirnov and Bartlett tests. If arcsine square root transformed data do not fulfill the assumptions of a normal distribution, non- parametric statistics (e.g. Kruskal-Wallis) should be used. Significant differences (p< 0.05) of mean survival, growth and reproduction are made using a one-way analysis of variance (ANOVA: Tukey HSD (honest significant difference) test or the Tukey HSD for unequal Nl). Non significant results are regarded as not toxic.

Applicant's summary and conclusion

Validity criteria fulfilled:

no

Executive summary:

The microdrile oligochaete Enchytraeus albidus was exposed to various concentrations of trivalent antimony (SbCl3) in an artificial soil and the endpoints mortality and reproduction were studied. The standard soil used is described and recommended by OECD (1984). This study was performed with 5 replicates per concentration, five concentrations (measured conc. range: 59.1 – 6980 mg Sb/kg dw) and a control (measured conc. 0.37 mg Sb/kg dw), with each replicate consisting of 10 enchytraeids with fully developed clitellum. Four replicates were used for the toxicity test and the remaining replicate was used for the chemical analyses. Adult enchytraeids were exposed for 21 days (which is the period in which cocoons are produced). After this period, the adult enchytraeids were removed from the soil and the survival was examined. The cocoons were incubated for another 21 days (i.e. a total of 42 days) after which reproduction was measured (number of young enchytraeids). The resulting NOEC and LOEC were 760 mg Sb/mg kg dw. and 2012 mg Sb/mg kg dw., respectively, for both endpoints. One of the three performance criteria specified in the OECD test guideline 220 (Enchytraeid reproduction test) that should be met in the control in order for the test to be valid is not fulfilled. This since the coefficient of variation around the mean number of juveniles that should not be higher than 50% at the end of the reproduction phase was 81%. The results from this study are therefore considered not reliable.