Propanoic acid, 2-hydroxy-, ammonium salt (1:1), (2S)-

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

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

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

ca. 28.8 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

NH3-N

Basis for effect:

mortality (fish)

Remarks on result:

other: 95 % CI = 9.92-12.4

Reported statistics and error estimates:

LC50 values and 95 % confidence intervals were estimated using the trimmed Spearman-Karber method.

Validity criteria fulfilled:

not applicable

Remarks:

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

Conclusions:

The lowest 96 h LC50 value (worst-case approach) among fish of the guideline-recommended size (5.0 ± 1.0 cm) was 28.8 mg/L (95% C.I. = 27.0–30.7).

Executive summary:

In a 96-h acute toxicity study, rainbow trout (Oncorhynchus mykiss, reported as Salmo gairdneri) were exposed to ammonium at measured concentrations (exact values not reported) under flow-through conditions. According to OECD 203 (OECD 1992) the recommended total length of test fish Oncorhynchus mykiss should be 5.0 ± 1.0 cm. Therefore, the results on fish in this size range as reported in the publication are used to describe the aquatic toxicity of ammonia to hatchery-reared rainbow trout. In a worst-case approach, the lowest among these LC₅₀ values of 28.8 mg/L (NH₃-N) is taken forward to the risk assessment. Sublethal effects were not reported.

This toxicity study is classified as acceptable and satisfies the guideline requirement for fish toxicity studies, with some reporting deficiencies that do not compromise the overall quality of the study.

Results synopsis

Test organism size (mean length): 5.0 ± 1.0 cm

Test type: Flow-through

LC₅₀: 28.8 mg NH₃/L (95 % C.I. = 27.0–30.7 mg/L)

Endpoint(s) effected: Mortality

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:

short-term toxicity to fish

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 attached report in section 13 of IUCLID.

Reason / purpose for cross-reference:

read-across source

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

180 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

>= 195 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality (fish)

Details on results:

Test solutions were not neutralised. It is more than likely that the low pH value affected the survival of the fish. At the highest test concentration a pH of 3.25 was measured.

Sublethal observations / clinical signs:

The apparent toxicity of lactic acid to Brachydanio rerio can be explained by the low pH values of the test substance solutions. At the highest test concentration a pH of 3.25 was measured.

Validity criteria fulfilled:

yes

Conclusions:

The LC50 of L-(+)-lactic acid to Danio rerio was determined to be > 195 mg/L (mean measured concentration), which can be attributed to a pH effect.

Executive summary:

The acute toxicity of the test substance, a solution of about 80 % L-(+)-lactic acid, to the freshwater fish speciesBrachydanio reriowas determined according to OECD guideline no. 203 and under GLP.

The study was carried out as a semi-static test with daily replacement of the test solutions and with 10 fish for each concentration. The exposure duration was 96 hours. The nominal concentrations tested were 100, 180, 320, 560 and 1000 mg/L.

The test substance appeared to be completely dissolved at all concentrations tested (visually assessed). The actual concentrations of L-(+)-lactic acid were determined enzymatically with a Boehringer test kit. They were between 70 and 77 % of the nominal concentrations just after dosing (average 74 %). To test the stability the concentrations of L-(+)-lactic acid were also analysed just before renewal and were between 56 % and 82 % of nominal (average 72 %). Mean measured effect concentrations are thus obtained by correcting nominal test material concentrations by correcting for 80 % lactic acid concent and by the average 72 % measured values.

The results of the test were (as mean measured concentration of L-(+)-lactate):

96-h LC50 > 195 mg/L

96-h LC100 = 332 mg/L

96-h NOEC (mortality) = 104 mg/L

The apparent toxicity of lactic acid toBrachydanio rerio can be explained by the low pH values of the test substance solutions. At the highest test concentration a pH of 3.25 was measured.

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

The potential toxicity of ammonium-S-lactate to fish is composed of contributions by both the S-lactate and the ammonium ion. In a short-term toxicity test on lactic acid mortality was observed resulting in estimated an LC₅₀ value of > 195 mg/L (mean measured) which can be attributed to a pH effect. Lactate as such is considered not to exert any systemic effects on fish in the tested concentration range of up to 560 mg/L.

The toxicity of the ammonium ion to fish was determined in a series of 96-h tests, resulting in a lowest (most conservative) LC₅₀ (96-h, Oncorhynchus mykiss) of 28.8 mg NH₃-N/L (Thurston 1983). Accordingly, the potential toxicity of ammonium-S-lactate is solely determined by the ammonium ion. Stoichiometric conversion to ammonium-S-lactate results in an LC₅₀ (96 h) of 222 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

ca. 222 mg/L

Additional information

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-acrross report attached to IUCLID section 13.