Glycollic acid

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

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 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 5 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 5 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Sublethal observations / clinical signs:

No lethality was observed, after 48 or 96 h. The same applies to the control group.

Validity criteria fulfilled:

yes

Conclusions:

Brachydanio rerio (zebra fish) were exposed for 96 h to a nominal concentration of 5000 mg/L glycolic acid (57%) in an acute limit test conducted according to OECD 203. No mortality was observed, therefore the 96 h LC50 was observed to be > 5000 mg/L.

Executive summary:

Brachydanio rerio (zebra fish) were exposed for 96 h to a nominal concentration of 5000 mg/L glycolic acid (57%) in an acute limit test conducted according OECD 203. No mortality was observed, therefore the 96 h LC50 was > 5000 mg/L.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 February to 31 May, 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

June 18, 2019

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

One sample from the stock solution and duplicate samples from the freshly prepared test medium of the only test concentration and the control were taken at the start of the test and from the freshly prepared test media at day 3. To determine test item stability under test conditions and the maintenance of test item concentrations throughout testing, duplicate samples from the test medium of the only test concentration and the control were collected at day 1 and at the end of the test (after 96 hours) from the 24-h aged test media from the approximate centre of the aquaria. The samples remained undiluted until sample preparation. All samples were stored in a freezer (≤ -20°C), protected from light until analysis was performed. Afterwards the samples were again stored deep frozen (≤ -20°C).

Vehicle:

no

Details on test solutions:

A stock solution of 1000 mg test item/L was prepared by dissolving 1523.8, 1508.6, 1520.1and 1542.5 mg test item into 1524, 1508.6, 1520.1 and 1543 mL test water by intense stirring for 10 to 35 minutes. The pH of the stock solutions was adapted to values of 7.0 to 7.9 by using 2 M NaOH. Adequate volumes of these stock solutions were diluted with test water to prepare the test medium of the desired test concentration of 100 mg test item/L. The test media were prepared just before introduction of the test fish (start of the test and test medium renewal on day 1, 2 and 3).

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Source: Forellenzuchtbetrieb Störk, 88348 Bad Saulgau, Germany;
Life stage: Juveniles;
Mean body length: 5.07 cm ± 0.2 cm;
Mean body wet weight 1.50 g ± 0.2 g;
Holding conditions and acclimatisation: All fish were obtained and held in the laboratory for at least 9 days before test initiation and maintained under the same conditions used in the test. Fish were fed three times per week or daily until 24 hours before the test was started. During the last 7 days prior to the start of the test no fish died in the test fish batch, therefore the mortalities in the fish batch were below 5 % and the fish batch was accepted.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Remarks on exposure duration:

No further remarks

Post exposure observation period:

Not applicable

Hardness:

1.78 mmol/L (= 178.4 mg/L) as CaCO3)

Test temperature:

12.4 to 14.0 °C

pH:

7.2 to 7.8

Dissolved oxygen:

94 to 100% of the air saturation value

Salinity:

Not applicable

Conductivity:

Not reported

Nominal and measured concentrations:

Nominal: 0 (control), 100 mg/L (pH adjusted)

Details on test conditions:

Tests were conducted in 16 L glass aquaria containing 14 L test medium. Test water (ISO medium) was prepared with deionised water (conductivity ≤ 10 μScm-1) in which analytical grade salts were added at the appropriate nominal concentrations. The test was performed with one replicate per treatment group. Seven fish were introduced into each aquarium in a random order at the start of the test. Fish were not fed during the test period. Test medium was renewed every day to keep the test item concentrations in the test media as constant as possible throughout the test period.

Tests were conducted within a controlled environmental room. The water temperature, pH-values and the dissolved oxygen concentrations were determined daily in the freshly prepared and aged test media of each treatment group. A photoperiod of 12:12 hours light:darkness (light intensity: 600 to 720 Lux) with a 30 minute dawn/dusk period was provided. The test media were slightly aerated during the test period.

The test fish were observed at test start and after approximately 2, 4, 20.5, 27, 42, 51, 70, 75 and 96 hours test duration for sublethal effects and mortality. At test end the fish were euthanized with a temperate 0.05 % Tricain solution (Ethyl 3-aminobenzoate methanesulfonate salt).

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

In the control and 100 mg/L test concentration, all fish survived until the end of the experiment and showed no sublethal effects during the exposure time. No fish died in the control and the dissolved oxygen concentration in the test media did not fall below 94% of the air saturation value, thus all validity criteria were met. In the freshly prepared test media at the start of the test and at the renewal of the test media, 104% of the nominal test concentration were found. In the aged test media after 24- and 96-hours test duration, 104 % of the nominal value was determined. Results therefore refer to nominal values, since the concentrations of the test item were within ± 20 % of the nominal concentrations during the test.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

No statistical analysis was performed. The LC50 could not be quantified due to the absence of toxicity of the test item but was estimated to be above the highest test concentration. The NOEC and the LOEC were determined directly from the raw data.

Sublethal observations / clinical signs:

Observed Mortality of unfed Rainbow Trout (Oncorhynchus mykiss) exposed to Glypure™ 99 for 96 hours

Nominal concentration [mg test item/L]	Mortality
	0 h	2 h	27 h	51 h	75 h	96 h
	# mort	# mort	# mort	# mort	# mort	# mort
Control	0	0	0	0	0	0
100	0	0	0	0	0	0
LC50 [mg/L]*	-	>100	>100	>100	>100	>100
95% CI.	-	n.d.	n.d.	n.d.	n.d.	n.d.

* Values refer to nominal test concentrations

# mort: Cumulative number of dead fish

n.d.: not determinable

CI.: Confidence interval

 

 

Summary of Analytical Results

Sample description [mg test item/L]	Fresh (0 h)			Aged (24 h)			Overall
	% of nominal^1	RSD [%]	n	% of nominal^1	RSD [%]	n	% of nominal^1	RSD [%]	n
Control	n.a.	n.a.	4	n.a.	n.a.	4	n.a.	n.a.	n.a.
100	104	2	4	104	1	4	104	1	8

¹mean value of all measured samples per treatment group

RSD: relative standard deviation per treatment group

n: number of analysed samples

n.a.: not applicable

 

 

Temperature [°C] in the Test Media

Nominal concentration [mg test item/L]		0 h	27 h	51 h	75 h	96 h
Control	New	13.7	13.5	12.5	12.5	-
	Aged	-	13.6	12.6	12.5	12.4
100	New	14.0	13.9	13.2	13.0	-
	Aged	-	13.5	12.5	12.4	12.6

 

 

pH-Values in the Test Media

Nominal concentration [mg test item/L]		0 h	27 h	51 h	75 h	96 h
Control	New	7.8	7.8	7.8	7.8	-
	Aged	-	7.5	7.7	7.7	7.7
100	New	7.2	7.5	7.5	7.7	-
	Aged	-	7.4	7.4	7.5	7.3

 

 

Dissolved Oxygen Concentrations [%] in the Test Media

Nominal concentration [mg test item/L]		0 h	27 h	51 h	75 h	96 h
Control	New	100	99	99	100	-
	Aged	-	96	97	97	97
100	New	100	98	99	99	-
	Aged	-	94	95	97	94

 

Validity criteria fulfilled:

yes

Conclusions:

In the 100 mg/L (pH adjusted) test concentration, all fish survived until the end of the experiment and showed no sublethal effects during the exposure time. The 96-hour LC50 and NOEC were therefore determined to be >100 and ≥100 mg/L (pH adjusted) based on nominal concentrations.

Executive summary:

The acute toxicity of Glypure™ 99 to Rainbow Trout (Oncorhynchus mykiss) was assessed according to OECD Guideline 203.

 

Juvenile test organisms were exposed in a semi-static test to a nominal test item concentration of 100 mg/L (pH adjusted) and a control for 96-hours. Test fish were observed at test start and after approximately 2, 4, 20.5, 27, 42, 51, 70, 75 and 96 hours test duration for sublethal effects and mortality.

 

In the freshly prepared test media at the start of the test and at the renewal of the test media, 104% of the nominal test concentration were found. In the aged test media after 24- and 96-hours test duration, 104 % of the nominal value was determined. Results therefore refer to nominal values, since the concentrations of the test item were within ± 20% of the nominal concentrations during the test. No fish died in the control and the dissolved oxygen concentration in the test media did not fall below 94% of the air saturation value, thus all validity criteria were met.

 

In the control and 100 mg/L test concentration, all fish survived until the end of the experiment and showed no sublethal effects during the exposure time. The 96-hour LC50 and NOEC were therefore determined to be >100 and ≥100 mg/L (pH adjusted) based on nominal concentrations.

Description of key information

Studies assessing the acute toxicity of glycolic acid to fish are available. The key 96-hour LC50 value (due to being the most conservative and reliable data available) was >100 mg/L (based on analytically confirmed nominal test concentrations), shown in the freshwater species, Oncorhynchus mykiss (Lührs and Sonntag, 2021). This key study was GLP compliant and met all validity criteria of the study guideline (OECD guideline 203).

Additional information

The experimental study performed by Haskell Laboratory for Toxicology and Industrial Medicine in 1990 was disregarded and invalidated. The pH was outside the acceptable range of 6 to 8.5. The pH was reported between 7.5 and 8.2 in the control group and at 64, 81, 100 and 130 mg/L treatments but decreased at 4.7 at 160 mg/L and 4.0 at 200 mg/L, where mortalities were observed. No mortality was reported up to 130 mg/L but 30% and 100% mortality were seen in the 160 and 200 mg/L treatments. Effects observed could be attributed to the strong acidic properties of the test substance.