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Short-term toxicity to fish

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Endpoint:
short-term toxicity to fish
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions
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:
read-across source
Qualifier:
according to
Guideline:
other: EPA-660/3-75-009 (1975)
GLP compliance:
yes
Analytical monitoring:
no
Test organisms (species):
Lepomis macrochirus
Details on test organisms:
The bluegill sunfish (ABC lot #2184) used in the test were obtained from Osage Catfisheries in Osage Beach, Missouri. The fish were identified to species using the taxonomie keys developed by Eddy (4). All test fish were held in culture tanks on a 16 hour
daylight photoperiod and observed for at least fourteen days prior to testing. Fish culture techniques used were basically those described by Brauhn et al. (5). A daily record of fish observations during the holding period, along with any prophylactic or therapeutic disease treatments, is included in the Appendix. During this period, the fish received a standard commercial fish food (Rangen's) daily until 48 hours prior to testing at which time feeding was discontinued. The bluegill sunfish used for this experiment had a mean weight of 0.37 (±0.15) g and a mean standard length of 24 (±2.3) mm. Weight and length measurements were made on the control group of fish at the termination of the test.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
None
Hardness:
40-45 mg/L
Test temperature:
22 degrees C
pH:
7.2-7.6
Dissolved oxygen:
9.0 mg/L
Nominal and measured concentrations:
Nominal concentrations of SY-83 0, 32, 56, 100, 180, 320 mg/L
Details on test conditions:
The static fish bioassay was conducted in five gallon glass vessels containing 15 liters of soft reconstituted water composed of the following compounds in the amounts stated per liter of deionized water:
48 mg NaHC03 30 mg CaS04-2 H20 30 mg MgS04
2mgKC1
This reconstituted water was prepared to yield a total hardness of 40-45 mg/1 as CaC03, a total alkalinity of 30-35 mg/1 as CaC03 and an initial pH of 7.2 to 7.6. The 0-hour measured control water parameters of this dilution water were dissolved oxygen 9.0 mg/1 and pH 7.2. The well water source from which this dilution water was prepared had the characteristics shown in Table 1.
The test vessels were kept in a water bath at 22°C (±1.0). The test fish were acclimated to the dilution water and test temperature and held without food for 48-96 hours prior to testing.
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
130 mg/L
Details on results:
The 24, 48 and 96 hour LC50 values for SY-83 were 140, 130 and 130 mg/1, respectively. All results were based on the nominal concentrations of 56, 100, 180, 320 and 560 mg/1. The no-effect concentration based on the lack of mortality and abnormal effects after 96 hours of exposure was 56 mg/1. The abnormal effects of mortality and surfacing were observed in the 100, 180, 320 and 560 mg/1 test concentrations during the 96 hour exposure period.
An examination of the fish culture and acclimation records for this test indicated that the fish were in good condition for testing.
Nominal test concentrations, mortality rates, and water quality data are presented in Table 3. The dissolved oxygen concentrations ranged from 5.6 to 9.0 mg/1 during the test. These values represented 64 and 102% saturation at 22°C, respectively, and were considered ade- quate for testing. The pH values ranged from 3.1 to 7.2, with decreasing levels as test concentrations increased.
Results with reference substance (positive control):
The bluegill sunfish were challenged with a reference compound, Antimycin A, to verify method precision. The 96 hour LC5o for bluegill sunfish exposed to Antimycin A was 1.0 X 10 4 mg/1 and was within the 95% confidence intervals reported in the literature.

Results are based on nominal concentrations.

Validity criteria fulfilled:
yes
Conclusions:
The nominal toxicity of lactic acid to bluegill sunfish is 130 mg/L.
Executive summary:

The acute toxicity of lactic acid to bluegill sunfish (Lepomis macrochirus) was assessed using the methods outlined by the Committee on Methods for Toxicity Tests with Aquatic Organisms. Water quality parameters of temperature, dissolved oxygen and pH were measured throughout the test and were within acceptable limits.

As a method precision check, the bluegill sunfish were challenged with a reference compound, Antimycin A. The estimated 96 hour LC50 and 95 % confidence limits (C.L.) were within the 95 % confidence limits reported in the literature. Culture and acclimation records indicated that the fish were in good condition for testing.

The study was conducted at the following nominal concentrations of lactic acid: 56, 100, 180, 320 and 560 mg/1. Ten fish, with a mean weight of 0.37 (± 0.15) g and a mean standard length of 24 (± 2.3) mm, were exposed to each test concentration and a blank control.

The results of the four day static fish toxicity studies using lactic acid and Antimycin A are summarized below. The 24 and 48 hour LC50 values were also determined.

Lactic acid:

LC50 (96 h) = 130 mg/L (95 % CI: 100–180 mg/L)

Antimycin A:

LC50 (96 h) = 1.0 × 10–4mg/L (95 % CI: 0.75–1.4 × 10–4mg/L)

Furthermore, the results indicate a 96-hour no-observed effect concentration of 56 mg/1, which was based on absence of mortality and abnormal effects.

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:
short-term toxicity to fish
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Older 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:
read-across source
Principles of method if other than guideline:
Method: other: EPA-669/3-75-009 (1975)
GLP compliance:
not specified
Analytical monitoring:
no
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
The rainbow trout (ABC lot #2684) used in the test were obtained from Trout Lodge in McMillan, Washington. The fish were identified to species using the taxonomie keys developed by Eddy
(4). All test fish were held in culture tanks on a 16 hour daylight photoperiod and observed for at least fourteen days prior to testing. Fish culture techniques used were basically those described by Brauhn et al. (5). A daily record of fish observations during the holding period, along with any prophylactic or therapeutic disease treatments, is in- cluded in the Appendix. During this period, the fish received a stand- ard commercial fish food (Rangen's) daily until 48 hours prior to test- ing at which time feeding was discontinued. The rainbow trout used for this experiment had a mean weight of 1.09 (±0.28) g and a mean standard length of 42 (±3.4) mm.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
none
Hardness:
40-45 mg/L
Test temperature:
12 degrees C
pH:
7.2-7.6
Dissolved oxygen:
9.2
Nominal and measured concentrations:
Nominal 0, 32, 56, 100, 180, 320 mg/L
Reference substance (positive control):
yes
Remarks:
Antimycin A
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
130 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
The 24, 48 Ind 96 hour LC50 values for SY-83 in the 96 hour static toxicity test with rainbow trout (Salmo gairdneri) were 150, 130 and 130 mg/L, respectively. All results were based on the nominal concentrations of 32, 56, 100, 180 and 320 mg/L. The no-effect concentration based on the lack of mortality and abnormal effects after 96 hours of exposure was 56 mg/L. The abnormal effects of mortality, surfacing and/or loss of equilibrium were observed in the 100, 180 and 320 mg/L test concentrations during the 96 hour exposure period.
The effects observed for positive control Antimycin A was within the 95% confidence intervals reported in the literature. An examination of the fish culture and acclimation records for this test indicated that the fish were in good condition for testing.

The dissolved oxygen concentrations ranged from 6.1 to 9.2 mg/L during the test. These values represented 56 and 85% saturation at 12°C, respectively, and were considered adequate for testing. The pH values ranged from 3.5 to 7.3. The pH values decreased with higher test concentrations.
The study was conducted following the intent of the Good Laboratory Practice Regulations and the final report was reviewed by Analytical Bio-Chemistry Laboratories' Quality Assurance Unit. All original raw data was provided to Union Oil Company, with a copy retained at Analytical Bio-Chemistry Laboratories.
Results with reference substance (positive control):
Antimycin A
96-hour LC50 4.8e-5 mg/1

Results are based on nominal concentrations.

Validity criteria fulfilled:
yes
Conclusions:
The toxicity of lactic acid to rainbow trout is 130 mg/L nominal concentration of test material.
Executive summary:

The acute toxicity of lactic acid to rainbow trout (Oncorhynchus mykiss, fromerly known as Salmo gairdneri) was assessed using the methods outlined by the Committee on Methods for Toxicity Tests with Aquatic Organisms. Water quality parameters of temperature, dissolved oxygen and pH were measured throughout the test and were within acceptable limits.

As a method precision check, the rainbow trout were challenged with a reference compound, Antimycin A. The estimated 96 hour LC50 and 95 % confidence limits (C.L.) were within the 95 % confidence limits reported in the literature. Culture and acclimation records indicated that the fish were in good condition for testing.

The study was conducted at the following nominal concentrations of lactic acid: 32, 56, 100, 180 and 320 mg/1. Ten fish, with a mean weight of 1.09 (± 0.28) g and a mean standard length of 42 (± 3.4) mm, were exposed to each test concentration and a blank control.

The results of the four day static fish toxicity studies on lactic acid and Antimycin A are summarised below. The 24 and 48 hour LC50 values were also determined.

Lactic acid:

LC50 (96 h) = 130 mg/L (95 % CI = 100–180 mg/L)

Antimycin A:

LC50 (96 h) = 4.8 × 10–5mg/1 (95 % CI = 2.4–7.5 × 10–5mg/1)

Furthermore, the results indicate a 96-hour no-observed effect concentration for lactic acid of 56 mg/1, which is based on the absence of mortality and abnormal effects.

Endpoint:
short-term toxicity to fish
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline 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:
read-across source
Qualifier:
according to
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: measured at 24 (fresh solutions) and 48 hours (spent solutions)
- Sampling method: separation of 250 ml from the bulk of the solution
- Sample storage conditions before analysis: NA
Details on test solutions:
Dilutions with water of a stock solution of 1000 mg/L (test material in water).
Test organisms (species):
Danio rerio (previous name: Brachydanio rerio)
Details on test organisms:
The organism used was the fresh-water fish species Brachydanio rerio from the commercial hatchery M.B. Ruysbroek B.V.(Noordvliet 159,Maassluis). The average total length and weight (± standard deviation) were 2.l ±0.17 cm and 0.07 ± 0.018 g respectively.
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 d
Post exposure observation period:
None
Hardness:
220 mg CaCO3 L-1
Test temperature:
ca. 24.5 °C
pH:
Dependent on lactic acid concentration. pH of medium 8.0. pH of highest test concentration 3.25
Dissolved oxygen:
≥ 7.3 mg L-1
Salinity:
Dutch Standard Water (the test medium) is a fresh reconstituted water.
Nominal and measured concentrations:
Nominal lactic acid 0, 80 144, 256 mg/L; actual 0-5, 45-60, 105-110, 180-210 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 2000 mL glass beakers, 1500 mL medium
- Aeration: only before adding fish
- Renewal rate of test solution (frequency/flow rate): once a day
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.7g / 1500 mL


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: DSWL
- Total organic carbon: 2 mg/L
- Metals: Na 1.26 mmol/L, K 0.23 mmol/L, Ca 1.41mmol/L , Mg 0.71 mmol/L
- Chlorine: 2.81 mmol/L


OTHER TEST CONDITIONS
- Adjustment of pH: NA
- Photoperiod: 16 h light 8 h dark


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


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Justification for using less concentrations than requested by guideline: expected effect concentration significantly higher than C&L limit.
Reference substance (positive control):
no
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
180 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
320 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
195 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
act. ingr.
Basis for effect:
mortality
Details on results:
No relevant details
Validity criteria fulfilled:
yes
Conclusions:
The LC50 of lactic acid to Danio rerio was determined to be 195 mg/L (mean measured concentration).
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 nominal 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 70 %).

The results of the test were (as nominal concentrations):

96-h LC50= 320 mg/L

96-h LC100= 560 mg/L

96-h NOEC (mortality) = 180 mg/L

96-h LC50= 195 mg/L (mean measured concentration)

The nominal concentrations quoted in this report relate to the test material (a solution of about 80 % L-(+)-lactic acid) as supplied by the sponsor.

Toxic effects are probably caused by acidification, since test solutions were not buffered or neutralised.

Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Secondary source and Japanese publication with English abstract, thus little information on the conduct of the experiments available.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Determination of the LC50 of pH to various salmonid species (Oncorhynchus mykiss, Salmo trutta, Salvelinus fontinalis, Salvelinus sp., Oncorhynchus rhodurus × masou) after 24 h exposure.
GLP compliance:
not specified
Analytical monitoring:
yes
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Test type:
not specified
Water media type:
freshwater
Limit test:
no
Total exposure duration:
24 h
Key result
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
ca. 3.83 other: pH
Nominal / measured:
meas. (not specified)
Conc. based on:
other: pH
Basis for effect:
mortality
Validity criteria fulfilled:
not specified
Conclusions:
The short-term toxic effects of pH (H+ ions) on five fish species after 24 h exposure were investigated. The LC50 (24 h) in the rainbow trout (Oncrhynchus mykiss) is pH 3.83.
Executive summary:

In a 24-h acute toxicity study, rainbow trout (Oncorhynchus mykiss) were exposed to acidity at various measured concentrations (pH measurement), presumably under static conditions. The 24-h LC50 was pH 3.83. Sublethal effects were not reported. Based on the results of this study, acidity can be considered to exhibit adverse effects on rainbow trout on a short time-scale (24 h) at pH of approximately 4 and lower.

This toxicity study is classified as supplementary information in the toxicity evaluation of acids; does not satisfy the guideline requirement for a short-term toxicity study but can nevertheless be used as supportive data or in a weight-of-evidence approach.

Results synopsis

Test organism: Rainbow trout (Oncorhynchus mykiss)

Test type: Static

LC50: pH 3.83

Endpoint(s) effected: Survival/mortality

Description of key information

In short-term toxicity tests of lactic acid in three different fish species mortality was observed resulting in estimated LC50 values ranging between 130 and > 320 mg/L (nominal) which can be attributed to a pH effect. Lactate as such is considered not exert any systemic effects on fish in the tested concentration range of up to 560 mg/L.

Key value for chemical safety assessment

Additional information

In four studies on short-term toxicity of lactic acid to fish (three different species: Danio rerio, Lepomis macrochirus, Oncorhynchus mykiss) mortality was observed resulting in estimated LC50 values ranging between 130 and > 320 mg/L (nominal). All studies are relatively poorly documented and therefore reliable only with restrictions. However, they can be used in a weight-of-evidence approach. In one of the studies (Bowmer et al., 1998) the observed mortality was explicitly attributed to pH effects: pH at the test concentrations of 320 and 560 mg/L was measured to be 4.1 and 3.5.

An additional published study (Molony, 2001; Ikuta et al., 1992) is quoted, demonstrating the detrimental effect of low pH values on survival of rainbow trout (O. mykiss): The LC50 (24 h) was determined at pH 3.83. If hypothetically exposed over the guideline-compliant period of 96 hours, the LC50 may be expected to be higher, i.e. approximately pH 4. Accordingly, the LC50 of pH 3.83 found by Ikuta et al. (1992) is considered as a worst-case in the context of evaluating pH effects of acids tested according to accepted test guidelines.

The theoretical pH shift caused by lactic acid at the lowest identified LC50 of 130 mg/L (= 1.443 mmol/L), considering a pKa of 3.9, would result in a final pH of 3.43. This compares quite well to the meausured pH values of 4.1 and 3.5 at test concentrations of 320 and 560 mg/L in a slightly buffered system (Bowmer et al., 1998).

Therefore, the mortality observed in the available short-term toxicity tests on fish can undoubtfully be attributed to a pH shift instead of being a toxic effect of the lactate ion/molecule. Accordingly, since any toxic effects of the lactate are of interest instead of acidification it can be concluded that within the tested concentration range (up to 560 mg/L) lactic acid does not cause lethal effects on fish, except pH related mortality. A key value (LC50) for chemical safety assessment hence cannot be identified.