Aluminium nitride

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

fish early-life stage toxicity

Type of information:

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

Adequacy of study:

weight of evidence

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

Duration:

60 d

Dose descriptor:

NOEC

Effect conc.:

ca. 22 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

other: Movement

Remarks on result:

other: pH 6.5

Duration:

60 d

Dose descriptor:

NOEC

Effect conc.:

ca. 22 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

behaviour

Remarks:

(strike frequency)

Remarks on result:

other: pH 6.5

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

ca. 26 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

other: Buoyancy

Remarks on result:

other: pH 6.5

Duration:

60 d

Dose descriptor:

NOEC

Effect conc.:

ca. 22 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

other: swimming capacity

Remarks on result:

other: pH 6.5

Duration:

60 d

Dose descriptor:

NOEC

Effect conc.:

ca. 13 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

number hatched

Remarks on result:

other: pH 6.5

Duration:

60 d

Dose descriptor:

NOEC

Effect conc.:

ca. 26 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

mortality

Remarks:

in fry

Remarks on result:

other: pH 6.5

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

ca. 13 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

length

Remarks on result:

other: pH 6.5

Duration:

60 d

Dose descriptor:

NOEC

Effect conc.:

ca. 26 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

weight

Remarks on result:

other: pH 6.5

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

ca. 22 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

other: RNA-content

Remarks on result:

other: pH 6.5

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

ca. 22 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

other: DNA-content

Remarks on result:

other: pH 6.5

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

ca. 13 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

dissolved

Remarks:

Al

Basis for effect:

other: RNA-DNA ratio

Remarks on result:

other: pH 6.5

Details on results:

Results from the REDEQL-EPAK modeling suggest that a large portion of the total aluminum present in these studies was in the solid, or undissolved, form. This was confirmed by the results obtained from the filtration procedures which showed that concentrations of dissolved aluminium were consistently low. Filtration of exposure water with 3.0-µm Teflon, 0.4 µm polycarbonate, 0.2 µm nylonand Fluoropore (Millipore Corporation, Bedford, MA), and 0.1 µm mixed cellulose-acetate and nitrate filters gave similar results. The filtration results, coupled with the REDEQL-EPAK estimates, suggest the presence of particulate or polymeric aluminum species larger than 3.0 µm.

- Mortality/survival at embryo, larval, juvenile, and adult stages: Embryo mortality not significantly different from the control at 350 µg/L (6 %)
- Number hatched, number of offspring produced, or number of offspring per live female per day: Control, about 46 (93 % hatch rate of 50 embryos)
- Observations on body length and weight of young and/or exposed parents at one or more time periods: See Table 5a for length data and Table 5b for weights
- All other template details: Not reported
- Number of fish in swim-up stage at one or more time periods (e.g., day ×1, ×2): No data
- Observations on body length and weight of young and/or exposed parents at one or more time periods: No data
- Number of healthy fish at end of test: No data
- Type of and number with morphological abnormalities: No data
- Type of and number with behavioural abnormalities: No data
- Type and number of developmental effects: No data
- Type and magnitude of hormonal changes: No data
- Other biological observations: No data
- Effect concentrations exceeding solubility of substance in test medium: No
- Incidents in the course of the test which might have influenced the results: No data

Reported statistics and error estimates:

One-way analysis of variance was used to compare treatment effects on survival, growth, behaviour, and nucleic acid content in both exposures. Percent data were arcsine transformed, and square root transformations were made on strike frequency and water column position data prior to statistical analyses. The Least Significant Difference means comparison test was used to distinguish differences among treatment means (p=0.05). Swimming capacity data were also analyzed by simple regression to determine the relation between swimming capacity and aluminium exposure concentration. Whole body residues of aluminium were analyzed as a completely randomized design in which the treatments were arranged factorially. The linear statistical model contained the effects of aluminium exposure concentrations, days of exposure, and interactions of exposure concentrations and days of exposure. Linear and quadratic polynomial orthogonal contrasts were computed to produce surface response plots for whole-body residues of aluminum. Statistical Analysis Systems programs were used to perform all analyses on the mainframe computer system of the University of Missouri, Columbia, Missouri.

Variable	pH 5.6-5.7		pH 6.5-6.6
	30d	60d	30d	60d
Movement/2min	68 (15)	142 (24)	169 (26)	>350 (22)
Strike frequency	8(-)	142 (24)	4^d (-)	>350 (22)
Buoyancy	68 (15)	--	169 (26)	--
Swimming capacity	>292 (27)	29 (14)	88 (26)	>350 (26)
Incomplete hatch^a	8^b (-)	--	57 (13)	--
Fry mortality	142 (24)	142(24)	169 (26)	169 (26)
Length	142(24)	142 (24)	57 (13)	88 (26)
Weight	142^c (24)	68 (15)	88^c (26)	88 (26)
RNA Content	142 (24)	--	>350 (22)	--
DNA Content	>292 (27)	--	>350 (22)	--

Note: Values represent total aluminum and (in parentheses) total dissolved monomeric aluminum

a) Embryo responses were determined after all embryos had hatched or died.

b) Background aluminum measured in pH 5.7 control treatment

c) Determined at 45 days of exposure

d) Background in pH 6.5 control

Validity criteria fulfilled:

not applicable

Conclusions:

The lowest NOEC was determined to be 13 µg/L (measured dissolved Al) for the endpoints "incomplete hachting", "length", and "RNA-DNA ratio". Total extractable aluminium in samples that were extracted immediately without filtration ranged from 39 to 211 µg/L in exposure A (pH 5.5) and from 27 to 194 ug/L in B (pH 6.5). The study is complete despite some missing information on physicochemical parameters (DOC, dissolved oxygen) data can be used in a risk assessment as key data.

Executive summary:

The 60-day chronic toxicity of aluminium (test material: aluminium sulphate) to early life stage of brook trout (Salvelinus fontinalis) was studied under flow-through conditions. Fertilised eggs (eye stage, 200 per treatment level) of brook trout were exposed to control, pH corrected control, and test chemical concentrations of 50, 100, 200, and 400 µg Al/L (nominal).

Two experiments at pH 5.5 and 6.5 were conducted, but only pH 6.5 results are referred to for endpoint derivation, in order not to confound aluminium toxicity and acidity effects. The test system was maintained at 12 ºC and a pH of 6.5 to 6.6. The 60-day NOEC values, based on sublethal effects (hatching success, length, DNA-RNA ratio), were 13 µg/L, respectively (dissolved Al, measured concentration). Further sublethal effects taht were investigated during the study included behavioural parameters (movement, strike frequency), buoyancy, swimming capacity, length, weight, RNA content, DNA content. Fry mortality was also determined (NOEC = 26 µg/L, dissolved Al). The most sensitive endpoints were hatching success, length, and RNA-DNA ratio.

This toxicity study is classified as acceptable and satisfies the guideline requirement for early life toxicity study with fish, although pre-dating the OECD guideline for early life stage tests.

Results synopsis

Test organism: Eggs of brook trout, eye stage

Test type: Flow-through

NOEC: 13 µg/L (dissolved Al)

Endpoints effected: Hatching success, length, and RNA-DNA ratio

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:

fish early-life stage toxicity

Type of information:

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

Adequacy of study:

supporting 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

Duration:

45 d

Dose descriptor:

NOEC

Effect conc.:

ca. 75 µg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

other: mortality, weight, behaviour

Remarks on result:

other: 75 µg/L equivalent to 0.05 ppm (Al test concentration as reported in the study)

Details on results:

Aluminium toxicity at different pH values was observed, namely pH 7.0, 8.0, 8.5 and 9.0. Fish mortality was observed over a total time of

ALUMINIUM TOXICITY TESTS AT pH 9.0
Six week old fingerlings were used for this test. The fish showed immediate shock and heavy mortality within 48 hours. Fecal cast were widespread and gill hyperplasia was universal within three days. Fish did not accept food. Test conditions were terminated after 113 hours (4 days, 17 hours) by stopping the aluminum addition and allowing pH to return to ambient. Within 36 hours some fish began feeding and about one half showed lightening of coloration. No fright reaction to approacha ppearedu ntil after 5 days. By the sixth day, however, activity and feeding were near normal.

ALUMINIUM TOXICITY TESTS AT pH 7.0
The trout were eleven weeks old at the start of the test. All exposures were conducted for 45 days (1080 hours). The mean temperature for the test was 12.8 °C. Twenty five fish were used in each trough. The mean pH for the controls was 7.44 for the first seven days and 6.85 thereafter. At a mean concentration of 0.513 ppm aluminum added, the pH was 7.27 for the first seven days of exposure and 6.52 thereafter. Under these conditions, fish showed a darkening of coloration and reduced feeding activity beginning on the seventh day. Gill hyperplasia was observed on some individuals.
The average weight of the trout was 32.5 % of the control average as opposed to 94.1 % of the control average at the start of the test.

AVERAGE TIME OF 50 % MORTALITY
The toxicity of total aluminium concentrations of 5.2 ppm depends on the pH of the water. For near neutral pH of 7.0 to 7.5 the time of 50 % mortality are ca. between 37 and 39 days. At pH 8 the 50 % mortality values are significantly decreased to approximately 35 days decreasing almost sigmoidal at pH 8.5 to ca. 5 days until 50 % of fish died at the aluminium concentration of 5.2 ppm. At pH 9.0 after ca. 3 days 50 % of the fish died.

Aluminium toxicity at pH 8.0

Duplicate concentrations of 0.05 ppm, 0.52 ppm and 5.2 ppm aluminium were tested. The fish were approximately 6 months old at the start of the test. Exposure time was 45 days. pH was adjusted to 8.0 and average temperature was 12.9 °C. No mortality was observed in the control group with water of pH 8.0 but in the absence of aluminium. At pH 8.0, 90 % of the aluminium of 5.2 ppm (ca. 0.14 mg/L Al) was insoluble.

Observations (5.2 ppm): Within 24 h a slowdown of activity was observed. Food consumption was reduced drastically over the whole test period. After five days gill hyperplasia was evident. By the sixth day most fish experienced equilibrium problems or swimming on their backs. Colouration of fish was very dark, some nearly black. During the second week of exposure periods of increased activity and feeding occured for the duration of one day. Changes in behaviour could be observed. Late in the test trout could be trodded without attempting to flee. Respiration rates were significantly increased. Weight was increased by around 30 %.

Observation (0.514 ppm): fish were slightly less active compared to control after one day, after six days fodd consumption was significantly reduced. Darker colouration was evident but not as pronounced as in the test with 5.2 ppm. Fright reaction noticeably drecreased after 10 days of exposure. At the end of the test all fish showed hyperplasia to some degree. In total 2 fish died. The average net weight increase was only 38% of the control fish.

Validity criteria fulfilled:

not applicable

Remarks:

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

Conclusions:

Toxic effects of aluminium to fish were studied at different pH values and concentrations. The aluminium concentrations were highly pH-dependent. At 0.05 ppm (ca. 75 µg aluminium/L) of dissolved aluminum, growth was excellent and behaviour normal.

Executive summary:

A study was performed to assess the toxic effects of aqueous aluminium complexes in neutral and basic media to rainbow trout fingerlings under constant flow conditions for 45 days. Principal components were eight troughs, three aluminium administering devices, a hydroxide diluter, heating and cooling units, and a pressure regulating reservoir. Fingerlings were raised in a water supply different from that of the toxicological test. The trout were hatched and reared to test size in well water and exposed to aluminium after acclimatization. Tested concentrations were 0.05 ppm, 0.52 ppm and 5.2 ppm at different pH values (7.0, 8.0, 8.5, 9.0) Behaviour, growth and mortality were recorded.

At 0.05 ppm dissolved Al (all pH values) growth and behaviour were not negatively affected, none of the fish died, whereas at higher Al concentrations pronounced effects regarding behaviour, growth and mortality could be observed.

Results synopsis

Test organism age: fingerlings

Test type: Flow-through

NOEC = 0.05 ppm dissolved Al

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.

Endpoint(s) effected: Behaviour, Growth, Mortality

Reference 3

Endpoint:

fish short-term toxicity test on embryo and sac-fry stages

Type of information:

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

Adequacy of study:

supporting 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

Duration:

120 h

Dose descriptor:

LC50

Effect conc.:

ca. 731.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

120 h

Dose descriptor:

LC50

Effect conc.:

ca. 65.8 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

aluminium

Basis for effect:

mortality

In embryo toxicity tests on D. rerio according to OECD Guideline 212, pH of the tested solution was lowered in dependence on PAX-18 concentration. The pH at the highest concentration (1800 mg per liter) was approximately 4.5. In contrast to juvenile life stages and based on other results it seems that embryonic life stages of this species are not very sensitive to acidic conditions.

The pH 4 did not affect the survival and hatching of embryos during embryo-toxicity test (according OECD 212 methodology).

Hatching was stimulated when pH was lowered from 7 to 6 but further lowering of pH retarded hatching (in absence of Al). Aluminium was more toxic at high pH levels.

Validity criteria fulfilled:

not specified

Conclusions:

The LC50 mean value of PAX-18 for embryonic stages of D. rerio was 731.5 +/- 94.1 mg/L (65.8 +/- 8.5 mg/L of Al).

Executive summary:

In a 120-h acute toxicity study according to OECD 212, juvenile Danio rario were exposed to a preparation of aluminium containing PAX-18 at nominal concentrations of 700, 750, 800, 850, 900mg/L under semi-static conditions.  The 96-h LC₅₀was 67.5 +/- 2.8 mg Al/L.

This toxicity study is classified as acceptable and satisfies the guideline requirement for Danio rerio OECD 212 toxicity study.

 

Results Synopsis

Test organism size/ageht or length): 2 -3 months

Test Type: semi-static with renewal after 48 h

LC₅₀:  (aluminium) 67.5 +/- 2.8 mg/L

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 4

Endpoint:

fish early-life stage toxicity

Type of information:

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

Adequacy of study:

weight of evidence

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

Duration:

61 d

Dose descriptor:

LOEC

Effect conc.:

>= 2.4 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

other: NH3

Basis for effect:

length

Remarks:

and weight

Remarks on result:

other: effect on size of fry at emergence

Duration:

61 d

Dose descriptor:

NOEC

Effect conc.:

1.2 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

other: NH3

Basis for effect:

length

Remarks:

and weight

Remarks on result:

other: effect on size of fry at emergence

Details on results:

SHORT-TERM EFFECTS
Late alevins near emergence were the most sensitive of all life stages exposed NH3 during short periods. Eyed eggs exposed to NH3 for 96 h were not harmed by concentrations > 1500 ppb.
The fry had been feeding for 2 week and appeared to have slightly greater tolerance to NH3 than the alevins tested, but the differences were not statistically significant.

EFFECTS OF LONG-TERM EXPOSURES TO AMMONIA ON SIZE OF FRY AT EMERGENCE
The highest exposure concentration of NH3 (4 ppb) caused significant decreases in weight (p < 0.05) of exposed fry in all three exposure groups. At exposure concentrations < 4 ppb, the groups held for 40 d and 61 d (B and C) were similar in response: both were significantly smaller in length and weight after exposure to 2.4 ppb NH3; after exposure to 1.2 ppb there was no significant difference. Effects were consistently more adverse for group C, the group receiving the longest exposures.

EFFECT OF AMMONIA ON EARLY EMERGENCE
Short-term (24 h) exposures to low concentrations of NH3 (25 ppb) did not stimulate early emergence during or immediately after exposure; emergence patterns were the same as those of unexposed fry. At higher concentrations (30-50 ppb) of NH3, early emergence of the alevins (up to 11 %) occurred within 24 h of exposures, but little residual effect was observed later when 50 % emerged at approximately the same date as unexposed alevins. earlyemergence of the alevins (up to 12 %) occurred at high concentrations of 100-150 ppb NH3.

IMPLICATIONS OF AMMONIA EXPOSURE STUDIES
Only for very high ammonia concentrations some immature fry was observed immediately after short-term exposure. These high concentrations are not liekly to be encountered in natural or hatchery environments. Adult trout exposed to NH3 have increased metabolic rates, and NH3 probably has the same toxic action in fishes as in mammals (impairment of cerebral energy metabolism).
The lowest concentration of NH3 that caused fry to be significantly smaller in length and weight at emergence was 2.4 ppb (61 and 40-d exposures). This concentration is about one twentieth of the concentration (50 ppb) that caused retardation of growth in rainbow trout fry that had been exposed continuously for about 67 d from the beginning of the egg stage (Burkhalter and Kaya 1977). Pink salmon alevins exposed to NH3 for 61 d at 4 °C in this study were more sensitive (as judged by effects on size) than the faster developing rainbow trout eggs and alevins exposed for about 67 d at 12 °C. In the trout study (Burkhalter and Kaya 1977), 25 d of the 67-d exposure were during the egg stage, a stage that is relatively tolerant compared with the alevin stage.

Reported statistics and error estimates:

Median tolerance limits (TLm's) and associated 95 % confidence limits were calculated by a computerized probit analysis program based on the method discussed by Finney (1971).

Validity criteria fulfilled:

not applicable

Remarks:

Non-guideline study, but scientifically robust result published in peer-reviewed article.

Conclusions:

Only for very high ammonia concentrations some immature fry was observed immediately after short-term exposure. These high concentrations are not likely to be encountered in natural or hatchary environments.
Exposure to naturally occurring ammonia is not a likely problem for salmon eggs and alevins in Alaska under natural or hatchery conditions where temperatures are low and waters are acidic-conditions that cause the percentage of NH3 to be very low (< 0.1 %).
The lowest concentration stated in the study which had no effect on the weight and length of migrant pink salom was given to ca. 1.2 ppb. This has been recalculated to be ca. 1.12 µg/L of un-ionized ammonia. The amount of un-ionized ammonia under the given pH and temperature conditions of the study is stated as < 0.1 %. This would lead to a very rough estimated amount of total (ionized) ammonia of > 1 mg/L.

Executive summary:

Eggs and alevins of pink salmon, Oncorhynchus gorbuscha, were exposed to un-ionised ammonia at concentrations of 0 (control), 0.02, 0.04, 0.2, 0.4, 1.2, 2.0, 4.0 ppb in a series of static and flow-through experiments to determine the levels of ammonia decreasing survival. Long-term tests (up to 61 days) with lower ammonia concentrations were conducted to determine effects on survival and size of fry at emergence. The lowest concentration of NH3 that caused fry to be significantly smaller in length and weight at emergence was 2.4 ppb (61- and 40-d exposures).

Results synopsis

Test organism age: eggs, alevins

Test type: Flow-through

NOEC = 1.2 ppm NH3

LOEC = 2.4 ppm NH3

Endpoint(s) effected: legth and weight of fry at emergence

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 5

Endpoint:

fish early-life stage toxicity

Type of information:

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

Adequacy of study:

weight of evidence

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

Duration:

73 d

Dose descriptor:

EC10

Effect conc.:

ca. 2.55 mg/L

Nominal / measured:

nominal

Conc. based on:

other: nitrogen as dissolved total ammonia

Basis for effect:

mortality

Remarks on result:

other: observed were 12.6 % mortality at this concentration (Yolk-sac fry).

Concentrations of ammonia as N (mg / l)		Mortality (% individuals entering stage)			Mortality (total) (%)
Total	Undissociated	Egg	Yolk-sac fry	Fry
Test A (started within 24 h of fertilisation)
0.14	-	8.8	1.6	2.6	12.6
2.55	0.022	65.2	12.6	4.9	71.1
4.52	0.039	78.5	33.6	2.7	86.1
8.00	0.069	87.3	44.1	0	92.9
15.50	0.128	72.1	26.8	4.7	80.6
25.77	0.219	97.9	64.5	20.0	99.4
Test B (started 24 days after fertilization)
0.19	-	2.2	4.0	3.6	9.5
2.59	0.023	3.3	9.6	11.6	22.7
4.74	0.041	3.2	5.7	2.5	11.0
8.15	0.072	3.4	3.8	3.5	10.3
15.72	0.130	3.4	11.2	8.3	21.3
25.92	0.226	3.3	14.0	27.5	39.7

Validity criteria fulfilled:

yes

Conclusions:

The results indicate that concentrations of undissociated ammonia as low as 0.022 mg per liter as N (or 2.55 mg per liter as total dissolved ammonia) could have a marked effect on the survival of rainbow trout eggs and fry if exposure began within 24 h of fertilisation. Mortality was heaviest in the egg but yolk-sac fry were still vulnerable. Seven weeks of exposure at a concentration of 0.23 mg per liter as dissolved NH3 (or 25.92 mg per liter total N of dissolved ammonia) did not produce a 50 % kill.

Executive summary:

Toxicity of ammonia to early life stages of rainbow trout (Salmo gairdneri) was examined in hard fresh water in a flow-through experiment with a total duration of 73 days. Two sets of experiments were performed, one where the exposure to ammonia (added in form of ammonium chloride) started within 24 h of fertilization an one set where the exposure started 24 days after examination. The experiments were performed in 15 L tanks. The tanks were opaque and fitted with opaque lids, the latter being partially removed before the fry began to feed independently (on a proprietary fry food).

Mortality > 70% was recorded at a concentration of 0.027 mg/L NH3 when exposure began within 24h of fertilization. In contrast, only 40 % mortality was noted at 0.27 mg/L NH3 when exposure did not start until the eyed-egg stage (c. 24 days).

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.

Description of key information

Aluminium nitride is susceptible to hydrolysis in aqueous compartments yielding aluminium and ammonium as degradation products with aluminium being the compound relevant for risk assessment. The lowest available NOEC value describing the long-term toxicity of aluminium towards fish is 13 µg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

NOEC

Effect concentration:

13 µg/L

Additional information

Freeman et al. (1971) studied the toxic effects of aqueous aluminium complexes in neutral and basic media to rainbow trout fingerlings under constant flow conditions. The trout were hatched and reared to test size in well water and exposed to aluminium after acclimatization. The study was performed at various pH values and aluminium concentrations. Behaviour, growth and mortality were recorded. The lowest no-effect concentration (NOEC) was found to be 0.05 ppm (ca. 75 µg aluminium/L).

In addition, the 60-day chronic toxicity of aluminium (test material: aluminium sulphate) to early life stage of brook trout (Salvelinus fontinalis) was studied under flow-through conditions (Cleveland et al., 1989). Fertilised eggs (eye stage, 200 per treatment level) of brook trout were exposed to control, pH corrected control, and various test chemical concentrations. The test system was maintained at 12 ºC and a pH of 6.5 to 6.6. The 60-day NOEC values, based on sublethal effects (hatching success, length, DNA-RNA ratio), were 13 µg/L, respectively (dissolved Al, measured concentration).

In a 120-h acute toxicity study according to OECD 212 (Macova et al., 2010), juvenile Danio rerio were exposed to a preparation containing aluminium at nominal concentrations of 700, 750, 800, 850, 900 mg/L under semi-static conditions. The 96-h LC₅₀ was 67.5 ± 2.8 mg Al/L.

As results obtained from tests according to OECD 212 (Fish, Short-term Toxicity Test on Embryo and Sac Fry Stages) are considered less sensitive compared to results obtained under the conditions of the FELS test (OECD 210), the results obtained by Macova et al. (2010) are not further considered in the risk assessment.

In the study by Rice et al. eggs and slevins of pink salmon (Oncorhynchus gorbuscha) were exposed to ammonia in a series of static and flow-through experiments to determine which levels of ammonia would decrease survival. Long-term tests (up to 61 days) with lower ammonia concentrations were conducted to determine effects on survival and size of fry at emergence. The value stated in the study which had an effect on the weight and length of migrant pink salmon was given to ca. 2.4 ppb. This has been recalculated to be ca. 2.24 µg/L of un-ionised ammonia. The amount of un-ionised ammonia under the given pH and temperature conditions of the study is stated as < 0.1 %. This would lead to a very rough estimated amount of total (ionised) ammonia of > 2 mg/L. The possibility of ammonia stimulating emergence of immature fry was tested at various stages of development. Only for very high ammonia concentrations some immature fry was observed immediately after short-term exposure. These high concentrations are not likely to be encountered in natural or hatchery environments.

Solbe et al. (1989) examined the toxicity of ammonia (NH3) to early life stages of rainbow trout (Salmo gairdneri) in hard fresh water in a flow-through experiment with a total duration of 73 days. Two sets of experiments were performed, one where the exposure to ammonia (added in form of ammonium chloride) started within 24 h of fertilization (Test A) and one set where the exposure started 24 days after examination (Test B). Mortality > 70 % was recorded at a concentration of 0.027 mg/L NH3 when exposure began within 24h of fertilization. In contrast, only 40 % mortality was noted at 0.27 mg/L NH3 when exposure did not start until the eyed-egg stage (c. 24 days). EC₁₀ values were 0.14 mg total ammonia (NH3 + NH4) per litre and 0.19 mg total ammonia/L in test A and B, respectively.

The NH3 effect values are not used as basis for the risk assessment because this would overestimate the toxicity of ammonium in aqueous solution drastically. If ammonia comes in contact with water it will form an equilibrium between the ionised and the unionised form which is highly on the side of the ionised form, slightly depending on temperature and pH. Nevertheless, the amount of ionised ammonium will be much higher compared to the NH3-form. For this reason the environmental risk characterisation will be performed on the basis of the lowest NOEC value identified for aluminium. The contribution of ammonia to the toxicity against fish, which is significantly lower, can be ignored.