Aluminium nitride

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

GLP compliance:

not specified

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

316 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Al

Basis for effect:

mortality

Remarks on result:

other: pH-range 3.21-3.52

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

359 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Al

Basis for effect:

mortality

Remarks on result:

other: pH-range 3.69-4.38

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Al

Basis for effect:

mortality

Remarks on result:

other: pH-range 4.37-6.70

Duration:

6 wk

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Al

Basis for effect:

growth

Remarks on result:

other: growth phase B+C, pH 3.4

Duration:

6 wk

Dose descriptor:

NOEC

Effect conc.:

320 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Al

Basis for effect:

growth

Remarks on result:

other: growth phase B+C, pH 4.3

Duration:

6 wk

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Al

Basis for effect:

growth

Remarks on result:

other: growth phase B+C, pH 7.3

Duration:

6 wk

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Al

Basis for effect:

other: cocoon production

Remarks on result:

other: growth phase B+C, pH 3.4, 4.3 and 7.3

Details on results:

Aluminium sulfate was most toxic at a pH of 3.4 with an LC50 of 589 mg Al/kg dry soil. At pH 3.4 growth and cocoon production were significantly reduced at 320 mg Al/kg dry soil, while at 1000 mg Al/kg dry soil all earthworms died.

Reported statistics and error estimates:

Trimmed Spearman-Karber method

Indicative LC50 and EC50 values for the effect of different aluminium salts on the survival and reproduction of Eisenia andrei after 14 (or 18) days exposure in range-finding tests in OECD artificial soil at different soil pH (1 M KCl) levels.

Aluminum salt	pH (mean±SD; n=5)	LC50 (in mg Al/kg dry soil)	EC50
Al2O3	2.41±0.11	>5000	n.d.
	3.35±0.05	>5000	n.d.
	4.47±0.05	>5000	n.d.
	7.12±0.02	>5000	n.d.
AlCl3.6H2O	3.21 – 3.52	316	n.d.
	3.69 – 4.38	359	n.d.
	4.37 – 6.70	>1000	n.d.
Al2(SO4)3.18H2O	3.24± 0.10	457	330
	4.86± 0.54	>4000	197
	7.22± 0.17	>4000	883

Table 3. EC50 values for the effect of aluminium sulfate on the growth and cocoon production of Eisenia andrei in OECD artificial soil at different soil pH (1 M KCl) levels. EC50 values are given for both three week exposure periods (indicated as phase B and C)

Endpoint	EC50 at soil pH (in 1 M KCL) [mg Al/kg dry soil]
	pH = 3.4	pH = 4.3	pH = 7.3
growth, phase B	322	992	>1000
growth, phase B	-	>1000	>1000
growth, phase B	189	>1000	>1000
cocoons, phase B	181	395	431
cocoons, phase B	309	774	292
cocoons, phase B	294	529	291

Table 4. NOEC values for the effect of aluminium sulfate on the growth and cocoon

production of Eisenia andrei in OECD artificial soil at different soil pH (1 M KCl) levels.

NOEC values are given for both three week exposure periods (indicated as phase

B and C)

Endpoint	NOEC at soil pH (in 1 M KCL) [mg Al/kg dry soil]
	pH = 3.4	pH = 4.3	pH = 7.3
growth, phase B	320	320	100
growth, phase B	100	320	>1000
growth, phase B	100	320	100
cocoons, phase B	100	320	100
cocoons, phase B	>1000	>1000	100
cocoons, phase B	100	100	100

Table 5. Effect of aluminium sulfate on the cocoon production of Eisenia andrei during a six week exposure period in OECD artificial soil at different soil pH (1 M KCl) levels

Concentration [mg Al/kg dry soil]	Number of cocoons ± SD (n=3) per 10 worms at pH [mg Al/kg dry soil]
	pH = 3.4	pH = 4.3	pH = 7.3
0	7.7 ± 3.1	18.0 ± 5.6	17.0 ± 4.0
10	8.7 ± 3.5	22.3 ± 3.8	22.3 ± 3.8
32	8.7 ± 2.3	16.7 ± 3.2	16.3 ± 5.1
100	9.0 ± 3.5	22.3 ± 5.8	20.3 ± 2.3
320	1.3 ± 2.3	11.0 ± 2.0	6.3 ± 4.2
1000	-	7.0 ± 3.6	5.3 ± 5.1

Validity criteria fulfilled:

not applicable

Remarks:

non-guideline study, but scientifically solid result published in peer-reviewed article

Conclusions:

A study was performed to determine the effects of three aluminium species on Eisenia andrei, Al2O3, AlCl3x6H2O and Al2(SO4)3x8H2O. Various endpoints were determined observing the growth and the number of cocoons. Effect concentrations (EC50) and no-observed-effect-concentrations (NOEC) were determined at different pH (3.4, 4.3 and 7.3). The lowest observed lethal concentration (LC50) was 316 mg Al/kg dry soil for AlCl3. The lowest no-observed-effect-concentration (NOEC) was 100 mg Al/kg dry soil.

Executive summary:

A study similar to OECD 207 and OECD 222 was executed in OECD (1984) soil with Eisenia andrei for 14 days (range-finding studies) and six weeks (main study). Test soils (400 g dry weight) were prepared with the toxicants and placed in 1 L glass test containers and 10 earthworms per container were added. In the first two range-finding tests, no food was added. In the third range-finding and in the main test, 4 g dry cow dung moistened with demineralized water to a level of 55 % (w/w) was added in a small hole in the middle of the soil of each test container.

For the range-finding tests one replicate was used per concentration and pH level. In the first and second range-finding tests survival of earthworms was assessed after 7 and 14 days, in the third range-finding test after 12 and 18 days. Test concentrations in the range-finding studies were as follows:

- Al2O3: 0, 10, 100, 1000, 5000 mg Al/kg dry soil were mixed in the soil

- AlCl3: 0, 10, 100, 1000 mg Al/kg soil

- Al2(SO4)3: 0, 10, 100, 1000, 4000 mg al/kg dry soil

The soil was moistured with a 0.009 M H2SO4 solution to obtain nominal soil pH values of 3.5, 5.0 and 7.0.

The test parameter in the first and second range-finding tests was survival, while in the third range-finding test also cocoon production was assessed.

AlCl3 appeared to be most toxic, with LC50 values of 316, 359 and >1000 mg Al/kg dry soil at pH(KCl) of 3.5, 4.4 and 6.7, respectively in the control soils. Effects of this salt interfered with a strong decrease of soil pH with increasing aluminium concentration. Al2(SO4)3 was less toxic with LC50 values of 457, >4000 and >4000 mg Al/kg dry soil at pH 3.24, 4.86 and 7.22, respectively. Al2O3 did not affect earthworm survival at concentrations of 5000 mg Al/kg and pH levels between 2.4 and 7.1.

In the main test soil samples were treated with Al2(SO4)3 at concentrations of 0, 10, 32, 100, 320, 1000 mg Al/kg dry soil. Nominal soil pH in the main test were 3.5, 4.5 and 6.5.

In the main test which consisted of three phases, three replicates were used for each concentration and pH level. In the phase A, adult earthworms were pre-incubated in untreated artificial soil for 1 week (pre-incubation phase). Afterwards (phase B), the earthworms were transferred to the aluminium-treated soils and exposed for three weeks (exposure phase). In the last exposure phase (phase C) test animals were transferred for another three weeks to treated soils. In the main test survival, weight change and cocoon production were determined.

The NOEC for the endpoint growth was 100 mg Al/kg soil dw and 320 mg Al/kg soil dw at pH 3.4/7.3 and 4.3, respectively. Cocoon production was not affected at 100 mg Al/kg soil dw (pH 3.4, 4.3 and 7.3).

This information is used in a read-across approach in the assessment of the target substance. For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.

Reference 2

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Description of key information

A study was performed to determine the effects of various aluminium species on Eisenia andrei. Various endpoints were determined observing the growth and the number of cocoons. Effect concentrations (EC50) and no-observed-effect-concentrations (NOEC) were determined at different pH (3.4, 4.3 and 7.3). After 14-d exposure the lowest observed lethal concentration (LC50) was 316 mg Al/kg dry soil. The lowest no-observed-effect-concentration (NOEC) after 6 weeks was 100 mg Al/kg dry soil (endpoints growth and cocoon production).
This endpoint has been waived for ammonia for exposure considerations. 

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

316 mg/kg soil dw

Long-term EC10, LC10 or NOEC for soil macroorganisms:

100 mg/kg soil dw

Additional information

A study was performed to measure the influence of different aluminium molecules on the earthworm Eisenia andrei. Earthworm toxicity of aluminium sulfate, chloride and oxide in both the range-finding (14-d exposure) and the main tests (6 week exposure) resulted in LC50 values between 316 to >5000 mg Al/kg dry soil.

For AlCl3 the LC50 values were determined to 316, 359 and >1000 mg Al/kg dry soil at pH 3.5, 4.4 and 6.7. For Al2(SO4)3 corresponding LC50 values of 457, >4000 and >4000 mg Al/kg dry soil at pH 3.24, 4.86 and 7.22 were measured. Al2O3 did not affect earthworm survival at concentrations of 5000 mg Al/kg and pH levels between 2.4 and 7.1. What can be seen as a result of its very poor water solubility.

Al2(SO4)3 was used in the main test to assess effects on growth and cocoon production at different concentration levels at different soil pH values. Growth and/or cocoon production were not affected at 100 mg Al/kg soil dw (pH 3.4, 4.3 and 7.3). For soil pH 4.3 growth was not affected at 320 mg Al/kg soil dw.

The toxicity of aluminium showed a clear pH dependence. From this study, it may be concluded that aluminium toxicity and its interaction with soil pH is complex and affected by many factors.

Nevertheless, aluminium is part of the natural soil environment and the found effect concentrations are in the range of several hundred milligrams.

For ammonia/ammonium this endpoint has been for exposure considerations. Ammonium/ammonia is part of the environment, particularly the natural soil compartment. It is furthermore used and spread into the environment in large scale as fertilizer. The un-ionized form ammonia is more toxic than ammonium which is a gas that is naturally produced in large scale by rotting microorganisms and plants. Both molecules are part of the nitrogen cycle and rapidly transformed into nitrate and nitrite.