Short Chain Fructo Oligosaccharides

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 Jun 2022 - 30 Jun 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identification: Actilight 950P Premium "Fructo-Oligosaccharides"
Substance: Short-chain fructo-oligosaccharides
EC No.: 908-300-1
Appearance: White powder
Purity: 95.4%

COMPOSITION:
scFOS is short chains of fructose molecules linked to a molecule of sucrose (glucose-fructose disaccharide). Thus, scFOS is a multiconstituent substance composed of three oligosaccharides: 1-kestose (GF2), nystose (GF3) and fructosyl-nystose (GF4).
With:
- TOTAL FOS: 95.4 expressed as dry matter
- Kestose (GF2): 39.2% FOS
- Nystose (GF3): 47.6% FOS
- 1F-Fructofuranosylnystose (GF4:) 13.6% FOS
- Glucose +Fructose + Saccharose : 4.6% expressed as dry matter

Analytical monitoring:

yes

Details on sampling:

Samples for possible analysis were taken from all test concentrations and the control at t=0, t=24 and t=48 hours. A sample of 2.0 mL was taken from the approximate center of the test solutions. Samples taken after 24 hours of exposure were taken from one replicate per test concentration. At the end of the exposure period, the replicates were pooled at each concentration before sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The batch of Fructo-oligosaccharides tested was a white powder with a purity of 95.4% and was visually completely soluble in test medium at the concentrations tested. No correction was made for the purity/composition of the test material. Preparation of test solutions started with the highest concentration of 100 mg/L. No other treatment than vigorous shaking was needed to completely dissolve the test material in medium. Lower test concentrations were prepared by subsequent dilutions of the highest concentration in test medium. All test solutions were clear and colorless at the end of the preparation procedure.
- Control: Test medium without test material or other additives.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: waterflea Daphnia magna (Crustacea, Cladocera) (Straus, 1820)
- Age at study initiation: neonates, less than 24 hours old, from parental daphnids of more than two weeks old
- Source: In-house laboratory culture with a known history
- Validity of batch: Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discolored animals and there was no delay in the production of the first brood.
- Feeding during test: no feeding during test

BREEDING
- Maximum age of cultures: 4 weeks
- Renewal of cultures: After 7 days of cultivation, half of the medium twice a week
- Temperature of medium: 18-22°C.
- Feeding: Daily, a suspension of freshwater algae.
- Culture medium: M7

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

180 mg/L (as CaCO3)

Test temperature:

21°C

pH:

At t=0 h: 7.5 - 7.6
At t=48 h: 7.9 - 8.0

Dissolved oxygen:

At t=0 h: 8.7 - 8.8 mg/L
At t=48 h: 8.3 - 8.8 mg/L

Nominal and measured concentrations:

Nominal: 0.10, 1.0, 10, 100 mg/L
Measured concentrations: due to decreasing measured concentrations, the geometric mean concentration was calculated: 0.073, 0.39, 8.8 and 100 mg/L (See 'Details on results' and Table 1 in 'Any other information on results incl. tables' for further details)

Details on test conditions:

TEST SYSTEM
- Test vessel: 60 mL, all-glass, containing 50 mL of test solution
- Aeration: no aeration
- Feeding: no feeding
- No. of organisms per vessel: 5 daphnids
- No. of vessels for the highest test concentration: 4
- No. of vessels for the intermediate test concentrations: 2
- No. of vessels per control: 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Medium prepared with tap water purified by Reverse Osmosis and the following salts: CaCl2.2H2O: 211.5 mg/L, MgSO4.7H2O: 88.8 mg/L, NaHCO3: 46.7 mg/L, KCl: 4.2 mg/L
- Culture medium different from test medium: Yes
- Intervals of water quality measurement: pH and dissolved oxygen: at the beginning and at the end of the test, for the highest test concentration and the control. Temperature of medium: continuously in a temperature control vessel, beginning at the start of the test.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h photoperiod daily.

EFFECT PARAMETERS MEASURED
- Immobility (including mortality) at 24 h and at 48 h.

RANGE-FINDING STUDY
- The test was performed as a Combined Limit/Range-Finding Test.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate, tested in a separate (non-GLP) study (performed April 2022)

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Analytical results:
See Table 1 for details. The measured concentrations at the start of the test were 0.11. 1.2, 10 and 101 mg/L for the nominal test concentrations 0.10, 1.0, 10 and 100 mg/L, respectively. After 24 hours of exposure, the concentrations remained quite stable. At the end of the exposure period, the concentrations of the lower test concentrations decreased to below LOQ. The concentration of the highest test concentration remained stable, i.e. was at 97% relative to initial at the end of the test.
Based on these results, the geometric mean concentrations were calculated and used to express effect parameters.

Biological results:
See Table 2 for details. All test conditions remained within the ranges prescribed by the study plan. No immobility was observed in the control and at any of the test concentrations throughout the exposure period. The 48h-EC50 for Daphnia magna exposed to Fructo-oligosaccharides was beyond the range of concentrations tested, i.e. exceeded the geometric mean concentration of 100 mg/L.

Results with reference substance (positive control):

The batch of Daphnia magna tested showed expected sensitivity to Potassium dichromate (24h-EC50: 0.57 mg/L with a 95% confidence interval ranging from 0.51 to 0.65 mg/L. 48h-EC50: 0.41 mg/L with a 95% confidence interval ranging from 0.36 to 0.48 mg/L) based on the historical range of reference tests performed by the Test Facility in the last ten years.

Reported statistics and error estimates:

No EC50 could be calculated because the test material proved to be not acutely toxic to Daphnia magna (EC50 > maximum concentration tested).

Table 1: Geometric Mean Concentration Versus Nominal Concentration

Fructo-oligosaccharides Nominal conc.  (mg/L)	Measured concentrations (mg/L)			Geometric mean conc. (mg/L)
	t=0h	t=24h	t=48h
0.10	0.107	0.0716	0.050 ^*	0.073
1.0	1.17	1.03	0.050 ^*	0.39
10	10.4	9.47	6.9	8.8
100	101	101	97.8	100

^* The analyzed concentration was below the limit of quantification (LOQ) which is 0.1 mg/L. Therefore half of the LOQ was used for calculating the geometric mean.

 

Table 2: Biological results

Time (h)	Replicate	Fructo-oligosaccharides Geometric mean conc. (mg/L)
		Control	0.073	0.39	8.8	100
0	A	5	5	5	5	5
	B	5	5	5	5	5
	C	5				5
	D	5				5
	Total introduced	20	10	10	10	20
24	A	0	0	0	0 (1)	0
	B	0	0	0 (1)	0	0
	C	0				0
	D	0				0
	Total immobilized	0	0	0	0	0
	Effect %	0	0	0	0	0
48	A	0	0	0	0	0
	B	0	0	0	0	0
	C	0				0
	D	0				0
	Total immobilized	0	0	0	0	0
	Effect %	0	0	0	0	0

( ) between brackets: number of daphnids observed trapped at the surface of the test solutions. These organisms were reimmersed into the respective solutions before recording of mobility.

Validity criteria fulfilled:

yes

Remarks:

See 'Overall remarks' for details on validity criteria

Conclusions:

The 48h-EC50 for Daphnia magna exposed to Fructo-oligosaccharides was beyond the range of concentrations tested, i.e. exceeded the geometric mean concentration of 100 mg/L.

Executive summary:

The toxicity of the ScFOS to the freshwater flea Daphnia magna was investigated in a GLP-compliant study performed in accordance with OECD Guideline No. 202.

A combined limit/range-finding test was performed. In this combined limit/range-finding test, 20 daphnids (4 replicates containing 5 daphnids each) for the control and highest test concentration and 10 daphnids (2 replicates containing 5 daphnids each ) for the intermediate test concentrations were exposed to the nominal concentrations of 0.10, 1.0, 10 and 100 mg/L under static conditions during 48 hours. An analytical monitoring was carried out at t=0, t=24, and 48 hours for each test concentrations.

As a results, after 24 hours of exposure, the concentrations remained quite stable. At the end of the exposure period, the concentrations of the lower test concentrations decreased. The concentration of the highest test concentration remained stable, i.e. was at 97% relative to initial at the end of the test. Therefore, based on these results, the geometric mean concentrations were calculated and used to express effect parameters.

No immobility was observed in the control and at any of the test concentrations throughout the exposure period.

In conclusion, the 48h-EC50 for Daphnia magna exposed to ScFOS was beyond the range of concentrations tested, i.e. exceeded the geometric mean concentration of 100 mg/L.

Description of key information

The toxicity of the ScFOS to the freshwater flea Daphnia magna was investigated in a GLP-compliant study performed in accordance with OECD Guideline No. 202.

Under the conditions of the study, no immobility was observed in the control and at any of the test concentrations throughout the exposure period. The 48h-EC50 for Daphnia magna exposed to ScFOS was beyond the range of concentrations tested, i.e. exceeded the geometric mean concentration of 100 mg/L

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 100 mg/L

Additional information

The toxicity of the ScFOS to freshwater flea Daphnia magna was investigated in one GLP-compliant study performed in accordance with standard methods, without deviations. The study is considered as reliable (Klimisch 1) and is selected as a key study for the endpoint.