Potassium triboron pentaoxide

Toxicity to terrestrial arthropods

Administrative data

Endpoint:

toxicity to terrestrial arthropods: long-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Study was performed according to ISO 11267 guideline and is well documented, but results for NOEC or EC10 are not reliable since a large significant effect (>20%) occured at first dose.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

ISO 11267 (Inhibition of Reproduction of Collembola by Soil Pollutants)

Deviations:

no

GLP compliance:

yes

Remarks:

The study has no formal GLP certificate. However, the study was conducted at a GLP-certified laboratory, staff was appropriately trained and standard operating procedures were followed in terms of experimental performance and raw data documentation.

Application method:

soil

Test material

Test material information

Constituent 1

Details on test material:

- Supplier: Sigma-Aldrich
- Batch No.: 016KO165;
- Purity: ≥ 99.5%
- Molecular weight: 61.8 g/mol
- pH-value: 3.8-4.8 (at 33 g/L H20, 20°C)
- Boiling point: 300°C
- Melting point: 160°C
- Flash point: non-flammable
- Ignition point: non-flammable
- Vapour pressure: 2.6 mm Hg (20°C)
- Density: 1.44 g/cm³ (20°C)
- Log Pow: 0.76 (25°C, IUCLID), no bioaccumulation to be expected
- Physical appearance: solid, white, cristalline
- Solubility in water: soluble, 50 g/L (21°C)
- Storage requirements: dry, at room temperature
- Stability under correct storage: stable

Sampling and analysis

Analytical monitoring:

no

Test substrate

Vehicle:

no

Details on preparation and application of test substrate:

- The test item was dissolved in a sufficient amount of deionised water to prepare a stock solution. This stock solution was diluted with deionised water to obtain one test item solution (= dosage solution) for each test item concentration.
- Method of mixing into soil (if used): The test item was incorporated into the soil by thoroughly mixing in the respective test item
solution for approx. 10 minutes.
- This amount of water/test item-mixture served also to adjust the final soil moisture of 40-60% of WHCmax

Test organisms

Test organisms (species):

Folsomia candida

Animal group:

Collembola (soil-dwelling springtail)

Details on test organisms:

The collembolans used in this test, Folsomia candida (Isotomidae, Collembola) were taken from a breeding culture kept at ECT Oekotoxikologie GmbH since August, 1999. The organisms were originally delivered by the University of Berlin. The collembolans were juvenile (with an age of 10 – 12 days); i.e. they were taken from a synchronised culture.

Study design

Study type:

laboratory study

Limit test:

no

Total exposure duration:

28 d

Test conditions

Test temperature:

20 ± 2 ºC

pH (if soil or dung study):

6 +- 0.5

Photoperiod and lighting:

16 : 8 h light/dark with a constant light intensity at the substrate surface of 400 – 800 lx

Details on test conditions:

TEST SYSTEM
- Test container (material, size):Test vessels were glass containers (able to be closed tightly) of about 200 mL capacity and with a diameter of about 5 cm.
- Amount of soil or substrate: 30 g fresh weight per test vessel
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 8

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- artificial soil based on OECD guideline 207 (1984). Percentages refer to dry weight:
- 5% Sphagnum peat (no visible plant remains; finely ground and air-dried)
- 20% Kaolin-Clay (kaolinite content > 30%)
- 74% Quartz sand (fine sand content with particles between 50 and 200 µm higher than 50%)
- ca. 1% Calcium carbonate (CaCO3)
- The moisture content was adjusted to 40 – 60% of WHCmax using deionised water.

OTHER TEST CONDITIONS
- Photoperiod: 16 : 8 h light/dark with a constant light intensity at the substrate surface of 400 – 800 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality and reproduction

The collembolans were fed with about 2 mg of granulated dry yeast per test vessel at the beginning of the test and after 14 days.

Nominal and measured concentrations:

nominal added concentrations: control, 18, 32, 56, 100, 178, 316, 562 and 1000 mg H3BO3/kg dry weight soil,
corresponding to control, 3.1, 5.6, 9.8, 17.5, 31.1, 55.2, 98.2 and 174.8 mg B/kg dw.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

< 3.1 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

added B

Basis for effect:

reproduction

Remarks:

number of juveniles

Effect concentrations 2

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

2 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

added B

Basis for effect:

reproduction

Remarks:

number of juveniles

Reported statistics and error estimates:

Mortality: The LC50 value was calculated by Probit analysis using Linear Max. Likelihood Regression.

Reproduction: For the determination of the NOECReproduction Data were checked for normality by R/s test procedure and for homogeneity by Cochran’s test. Treatment means were compared by ANOVA and Williams test (p ≤ 0.05, one-sided) and tested for statistically significant differences compared to the control. Probit analysis using Linear Max. Likelihood Regression was used to calculate the EC50, EC20 and EC10 for reproduction.

Any other information on results incl. tables

28 d LOEC for reproduction: 3.1 mg B/kg soil dw (28.2% inhibition)

28 d EC50 for reproduction: 7.6 mg B/kg soil dw

28 d EC20 for reproduction: 3.2 mg B/kg soil dw

28 d LC50 for mortality: 27.8 mg B/kg soil dw

Concentration [mg test item/kg soil (dw)]	Number of dead adult collembolans	Percent mortality
Control	5	6
18	5	13
32	8	20
56	5	13
100	5	13
178	20	50
316	38	95
562	40	100
1000	40	100

Concentration [mg test item/kg soil (dw)]	Number of Juveniles[mean ± sd]	Number of Juveniles[% of control]
Control	1244.0 +- 109.9	-
18	893.8 +- 63.1	71.8
32	849.5 +- 143.3	68.3
56	555.0 +- 122.9	44.6
100	204.0 +- 72.9	16.4
178	93.8 +- 25.9	7.5
316	0.0 +- 0	0.0
562	0.0 +- 0	0.0
1000	0.0 +- 0	0.0

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Study was performed according to ISO 11267 guideline and is well documented, but results for NOEC or EC10 are not reliable and therefore not used for PNEC derivation because a large significant effect (>20%) occured at first dose.