Rhodium chloride (RhCl3), hydrate

Toxicity to terrestrial arthropods

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to terrestrial arthropods: short-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: ISO 16387 OECD 220

GLP compliance:

no

Application method:

soil

Analytical monitoring:

no

Details on preparation and application of test substrate:

nominal concentrations 50, 100, 150, 200 and 250 μmol/L RhCl3

Test organisms (species):

other: Enchytraeus crypticus

Animal group:

other: Soil dewelling worm

Details on test organisms:

Originated in cultures from the Ecotoxicological laboratory of the University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic.

Study type:

laboratory study

Limit test:

yes

Total exposure duration:

28 d

Test temperature:

20 ± 2°C

pH (if soil or dung study):

6.0 ± 0.5

Humidity:

50% soil moisture

Photoperiod and lighting:

16:8 (light/dark) photoperiod

Details on test conditions:

Within each vessel, ten adult enchytraeids of approximately the same size, with eggs in the clitellum region were placed in 20g soil. As food supply, finely ground rolled oats were added. Additional food and water were added when required.

Nominal and measured concentrations:

nominal concentrations 50, 100, 150, 200 and 250 μmol/L RhCl3

Reference substance (positive control):

yes

Remarks:

Boric acid

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

246.6 other: μmol/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Details on results:

A significant effect on mortality and reproduction was observed.

Results with reference substance (positive control):

boric acid EC50 150– 170 mg/kg dry weight soil

Reported statistics and error estimates:

One-way analysis of variance (ANOVA) and post-hoc analysis of means by the LSD test.
Levene’s method was used to test for the homogeneity of variances.
Non-homogenous parameters were log-transformed prior to analysis and compared with the non-parametric Kruskal-Wallis test.

Concentrations RhCl3(μmol/L)	No. adult		Mortality (%)	No. juveniles produced (mean ± SD)	CV (%)	Inhibition of reproduction (%)
	at the beginning of the test	at the end of the test
50	10	10	0	128.8±16.5	13	1
100	10	9.2	8	126.0±21.8	17	3
150	10	9	10	124.4±17.7	14	4
200	10	6.2	38	95.2±15.7	16	27
250	10	4.4	56	60.6±26.7	44	53

Conclusions:

The 28 day EC50 was 246.6 μmol test item/L, based on reproduction

Executive summary:

The influence of rhodium trichloride on the reproduction and mortality of the species Enchytraeus crypticus was investigated according to OECD Test Guideline 220, "CSN EN ISO 16387 – Soil quality – Effects of pollutants on Enchytraeidae (Enchytraeus sp.) – Determination of effects on reproduction" (Havelkova et al. 2014). Test specimens were placed in synthetic soil treated with nominal rhodium trichloride concentrations of 50, 100, 150, 200, 250 µmol/L. The experiments were carried out with five replicates. The 28 day EC50 for rhodium trichloride was found to be 246.6 µmol test item/L. When the Enchytraeus crypticus were exposed to 250 µmol/L rhodium trichloride, the inhibition of reproduction was 53%. A significant effect of mortality was also observed.

This study has a reliability rating of 2 (reliable with restrictions). The study was not conducted according to GLP and although it followed a standard guideline only EC50 values were reported (a NOEC value is not included in the study) and results are based on concentrations of test solution not concentrations in test soil.

Reference 2

Endpoint:

toxicity to terrestrial arthropods: long-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 232 (Collembolan Reproduction Test in Soil)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

no

Application method:

soil

Analytical monitoring:

not specified

Details on sampling:

None.

Details on preparation and application of test substrate:

Test material dissolved in appropriate amount of deionised water to attain 50% soil moisture loading.
Stock solution made at 10 mmol/L (0.05231 g test material per 25 mL deionised water).

Test organisms (species):

Folsomia candida

Animal group:

Collembola (soil-dwelling springtail)

Details on test organisms:

- Source: Ecotoxicological laboratory of the University of Veterinary and Pharmaceutical Sciences

The following information was not specified but assumed to be the same as the study for platinum tetrachloride by Nemcova, 2012 ("Impact of platinum on the soil invertebrate Folsomia candida". Neuroendocrinology Letters, 33(3), 173-178).

- Age at test initiation (mean and range, SD): 10-12 days
- Substrate: plaster of Paris/charcoal mixture, 9:1
- Feeding: fed twice a week with dried baker's yeast, 24 hr fast before test start
- Temperature: 20 +/- 1 C
- Lighting: dark

Study type:

laboratory study

Limit test:

no

Total exposure duration:

28 d

Post exposure observation period:

None.

Test temperature:

20°C

pH (if soil or dung study):

6.0 +/- 0.5
Adjusted with calcium carbonate.
pH analysed in a 1:5 mixture of soil and 1 M potassium chloride

Humidity:

50% soil moisture

Photoperiod and lighting:

Light/dark cycle: 16/8
Light intensity: 400 - 800 Lux

Details on test conditions:

- Test container (material, size): glass, capped with polyethylene lid and sealed with Parafilm (with a small hole to allow airflow)
- Amount of soil or substrate: 30g, wet
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 5
- Substrate: standard artificial soil
- % sand: 70
- % silt: 0
- % clay: 20 (kaolin)
- % organic material: 10 (Sphagnum peat, finely ground)
- Feeding: 2 mg granulated dry yeast on days 1 and 14

Nominal and measured concentrations:

Nominal concentrations: 5, 10, 25, 50 and 100 uM test material per vessel

Reference substance (positive control):

yes

Remarks:

boric acid

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

266.22 other: µmol/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Details on results:

No significant effect on mortality was found.
Survival was not affected to such an extent as reproduction.

Results with reference substance (positive control):

28d EC50 for reproduction is 101.5 mg/kg for boric acid; expected value is 100 mg/kg dry weight soil.

Reported statistics and error estimates:

One-sided ANOVA followed by analysis of means by the LSD test.
Levene's method to test for homogeneity of variances.
Non-homogenous parameters were log-transformed prior to analysis and compared with the non-parametric Kruskal-Wallis test.

Test material concntration (uM)	# juveniles produced	CV (%)	SD	Inhibition of reproduction (%)
5	555.74	7	41.8	8
10	542.8	15	78.8	10
25	508.6	21	107.6	16
50	454.6	11	48.8	25
100	326.8	14	46.6	46

Validity criteria fulfilled:

yes

Conclusions:

The 28-day reproduction EC50 was found to be 266.22 μmol test item/L.

Executive summary:

The influence of rhodium trichloride on the mortality, reproduction and growth of the species Folsomia candida was investigated according to OECD Test Guideline 232 (also CSN ISO 11267), "Inhibition of reproduction of Collembol by soil pollutants" (Nemcova et al. 2013). Test specimens were placed in synthetic soil treated with nominal rhodium trichloride concentrations of 5, 10, 25, 50 and 100 µM. Soil moisture was maintained at 50% and adjusted at three times a week with more water to account for system mass losses. No significant differences between the test concentrations and control were found for adult mortality. The 28-day reproduction EC50 for rhodium trichloride was found to be 266.22 µmol test item/L.

 

The study has a reliability rating of 2 (reliable with restrictions) as the number of test concentrations tested was not appropriate for the derivation of the ECx and a NOEC is not reported in the paper. The spacing factor is also higher than recommended and results are reported based on solution concentration and not concentration in the test soil. The composition of artificial soil varied slightly from that recommended in the guideline. The study was not conducted according to GLP.

Description of key information

The 28-day EC50 was found to be 266.22 μmol test item/L for Folsomia candida, based on reproduction. The 28-day EC50 was 246.6 μmol test item/L for Enchytraeus crypticus based on reproduction.

Additional information

Two studies are available for terrestrial toxicity for rhodium trichloride, with the species Folsomia candida (Nemcova et al. 2013) andEnchytraeus crypticus (Havelkova et al. 2014).

The influence of rhodium trichloride on the mortality, reproduction and growth of the species Folsomia candida was investigated according to OECD Test Guideline 232 (also CSN ISO 11267), "Inhibition of reproduction of Collembol by soil pollutants" (Nemcova et al. 2013). Test specimens were placed in synthetic soil treated with nominal rhodium trichloride concentrations of 5, 10, 25, 50 and 100 µM. Soil moisture was maintained at 50% and adjusted at three times a week with more water to account for system mass losses. No significant differences between the test concentrations and control were found for adult mortality. The 28-day reproduction EC50 for rhodium trichloride was found to be 266.22 µmol test item/L.

The influence of rhodium trichloride on the reproduction and mortality of the species Enchytraeus crypticus was investigated according to OECD Test Guideline 220, "CSN EN ISO 16387 – Soil quality – Effects of pollutants on Enchytraeidae (Enchytraeus sp.) – Determination of effects on reproduction" (Havelkova et al. 2014). Test specimens were placed in synthetic soil treated with nominal rhodium trichloride concentrations of 50, 100, 150, 200, 250 µmol/L. The experiments were carried out with five replicates. The 28 day EC50 for rhodium trichloride was found to be 246.6 µmol test item/L. When the Enchytraeus crypticus were exposed to 250 µmol/L rhodium trichloride, the inhibition of reproduction was 53%. A significant effect on mortality was also observed.

Both studies are assigned Klimisch scores of 2 as they generally follow standard test methods but they are non-GLP and there are some significant methodological details that are missing from the papers. The studies are not considered to be appropriate for use in PNEC derivation for rhodium(III) substances as only EC50 values are reported. Chronic NOEC values can be determined from the graphs included in the papers. However, results are reported as concentrations of solution applied to soil (in mg/L) and although it can be possible to convert these to mg/kg soil this would not be possible without further information as the amount of solution applied to the soil and amount of soil per vessel are not reported in the papers.