Alcohols, C13-15-branched and linear

Sediment toxicity

Link to relevant study record(s)

Reference

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Feb. 2022 to June 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 218 (Sediment-Water Chironomid Toxicity Test Using Spiked Sediment)

Version / remarks:

adopted 13. April 2004

Deviations:

yes

Remarks:

Fish food was used as food for the larvae. In deviation from the requirements of the OECD test guideline 218 which requires the feeding of plant material instead of fish food for strongly adsorbing substances.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

SEDIMENT
- Concentrations: all test concentrations after application, lowest and highest after 0 and 7 d
- Sampling interval: after application (all), additional replicate for each concentration for analysis is available (see table 1 for details)
- Sample storage before analysis: All samples were frozen (at -20 ± 5 °C) immediately after sampling (and separation of the pore water) and were kept stored frozen until analysis

WATER
- Concentrations: lowest and highest
- Sampling interval: taken from water column without mixing from analytic replicate after day 0 and 7
- Sample storage before analysis: All samples were frozen (at -20 ± 5 °C) immediately after sampling (and separation of the pore water) and were kept stored frozen until analysis.

PORE WATER
The water column was removed from tets beaker (siphoned off). The remaining wet sediment was recorded before analysis. The pore water was obtained by centrifugation of the wet sediment at approximately 10’000 g for approximately 30 minutes at about 4 °C. The resultant overlaying water is defined as pore water. This pore water was sampled after recording the total pore water volume of each sediment.

Vehicle:

yes

Remarks:

acetone (test substance was poorly soluble in water)

Details on sediment and application:

PREPARATION OF SPIKED SEDIMENT
- Pooling or mixing of different substrates: After evaporation, the sand was thoroughly mixed with the wet sediment from each single test vessel (120 g wet sediment) using a spatula and vortex mixer for 2–3 minutes.
- Details of spiking: defined amount of application solution (see table ) 10 g sand by distributing the solution dropwise over the whole surface
- Equilibration time: 2
- Equilibration conditions: same as test conditions
- Controls: analytical control after application
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): acetone
- Concentration of vehicle in test medium: see table 2
- Evaporation of vehicle before use: yes

PREPARATION OF THE WATER-SEDIMENT SYSTEM
The spiked sediments were transferred from the mixing flasks into the test vessels at a layer of approximately 1.5 cm depth. This amount corresponded to 130 g wet weight with 46% water content (or 89 g dry sediment). Next, the sediment surface was protected with a plastic plate, which floated when the 250 mL M7 medium was poured into the vessel very slowly, taking care not to disturb the sediment. The resulting water column had a depth of 6 cm. Thus, the ratio of the depth of the sediment layer to the depth of the overlying water was 1:4. After filling the vessels with M7 medium, the plastic plate was removed.

Test organisms (species):

Chironomus riparius

Details on test organisms:

TEST ORGANISM
- Common name: harlequin fly
- Source: maintained at IES Ltd Laboratories, fresh egg masses were used
- Details on collection: Twenty larvae of the first larval stage (three days old) were allocated randomly to each test vessel by means of a suitable pipette (four groups of five larvae each, per vessel).
- Breeding conditions: Six days before inserting the larvae into the test vessels, eight newly oviposited egg masses were taken from the test organism culture and deposited into small vessels in test water with a small amount of food (fish food suspension)
- Age of animals at beginning of exposure: 3 days, first-instar larvae
- Feeding during test: yes
- Food type: grounded fish food flakes suspended in test water
- Amount: 0.467 ml/vessel = 23 mg food/vessel on days -2, 0, 3, 5, 19, 21, 24 and 26; 0.934 ml/vessel = 47 mg food/vessel on days 7, 10, 12, 14 and 17.
- Frequency: at least three times per week

Study type:

laboratory study

Test type:

static

Water media type:

freshwater

Type of sediment:

artificial sediment

Limit test:

no

Duration:

28 d

Exposure phase:

larvae from first generation (P)

Hardness:

270 -360 mg/L as CaCo3 (see table 3)

Test temperature:

18.8-19.7 °C (see table 3)

pH:

see table 3

Dissolved oxygen:

see table 3

Ammonia:

0.367 - 5.1 mg/L see table 3

Nominal and measured concentrations:

nominal: control, solvent control, 46, 100, 220, 460 and 1000 mg test item/kg sediment

Details on test conditions:

TEST SYSTEM
- Test container (material, size): Glass beakers (600 mL, approximately 8 cm in diameter)
- Sediment layer: 1.5 cm depth
- Weight of wet sediment with and without pore water: 130 g wet weight with 46% water content (or 89 g dry sediment)
- Water column: 6 cm depth
- Water volume: 250 ml
- Aeration: yes
- Aeration frequency and intensity: gently aerated through a glass Pasteur pipette, fixed above the sediment layer, continuously (except for larvae introduction, 2 h)
- Replacement of evaporated test water, if any: the water level did not change by more than 10 % during test. Level was filled up regularly with purified water

EXPOSURE REGIME
- No. of organisms per container (treatment): 20
- No. of replicates per treatment group: 3
- No. of replicates per control: 3
- No. of replicates per solvent control: 5
- Food type: grounded fish food flakes suspended in test water
- Amount: 0.467 ml/vessel = 23 mg food/vessel on days -2, 0, 3, 5, 19, 21, 24 and 26; 0.934 ml/vessel = 47 mg food/vessel on days 7, 10, 12, 14 and 17.
- Frequency: at least three times per week

RENEWAL OF OVERLYING WATER
- Details on volume additions:

OVERLYING WATER CHARACTERISTCS
- Type of water: reconstituted water ("M7-medium")

CHARACTERIZATION OF ARTIFICIAL SEDIMENT
- % dry weight of sphagnum moss peat: 4.5 (air dried, very finely ground to ≤ 1 mm)
- % sand: 75.5 (Quarzsand A 0.06 – 0.25 mm): 0.25 mm 1.5 %; 0.18 mm 16.5 %; 0.125 mm 54.5 %, 0.09 mm 23.5 %; <0.09 mm 4.0 %
- % kaolin clay: 20; (content of kaolinite: 52 %; content of Al2O3: 31.5 %)
- % Calcium carbonate (CaCO3): 0.42-0.43
- Composition (if artificial substrate):
- Method of preparation (if artificial substrate): All dry constituents were weighed in the correct portions. The finely ground peat was moistened with purified water by intense mixing using an ultra-turrax and then gentle stirring for three days at room temperature in the dark. Then all constituents (and some CaCO3) were thoroughly blended in a laboratory mixer to give a homogeneous wet sediment. With the added purified water, a sufficient moisture of the final sediment mixture was obtained.
- Moisture: 46 % of the sediment dry weight
- Metals [mg/kg]: Pb = 5.0, Cd= <0.1, Cr=13.3, Cu = 2.6, Mo <1, Ni =3.5, Hg < 0., Zn =15.1,
- pH whole sediment: 7.3
- Total organic carbon (%): 2.0 % based on dw
- Proof of absence of chemical contaminants: the sediment was analyzed for heavy metals and chemicals (study report: 421-0550, Labor Veritas AG) according to APO_LI_014 (version 04/13.09.2019). No pesticides were detected

OTHER TEST CONDITIONS
- Photoperiod: 16-hour light to 8-hour dark
- Light intensity: 781–921 Lux (measured approximately at water surfaces of the test beakers)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Emerging ratio: day 10 to 28 (daily) (male, female and pooled sexes)
- Developmental rate separately or both sexes and for the pooled sexes

VEHICLE CONTROL PERFORMED: yes

RANGE FINDING STUDY: yes
Three range finding studies were conducted. Study 1 (concentrations: 1.0, 10, 100, 1000 mg/kg dry sediment, control and solvent control) and 2 (concentrations: 62.5, 1000 mg/kg dw sediment, control and solvent control were conducted with plant based food but were invalid. A third study with fish food was valid. As it was not possible to perform a valid study using plant diet (Urtica dioeca) and taking into account that the validation of the OECD test guideline 218 did not include a different diet than fish food, the diet was changed to the diet described in the study plan and a third range finding study was conducted.
Concentrations of third range finding study: 62.5, 1000 mg/kg dw sediment, control and solvent control

Reference substance (positive control):

no

Key result

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

847 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

emergence rate

Remarks on result:

other: effect value for pooled sexes

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

> 1 000 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

development rate

Remarks on result:

other: effect value for female

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

901 mg/kg sediment dw

95% CI:

166 - 1 000

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

development rate

Remarks on result:

other: effect value for male

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

> 1 000 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

development rate

Remarks on result:

other: effect value for pooled sexes

Details on results:

see table 5

Table 4: Effect values based on the nominal initial test item concentrations in the water column

	28-Days ECX Values Based on Nominal Concentrations [mg/kg dry sediment]
	Emergence Rate of Pooled Sexes	Developmental Rate
		Female	Male	All
EC10 (95 % confidence limits)	847 (n.d.)	>1000	901 166 – >1000	>1000
EC15	>1000	>1000	>1000	>1000
EC50	>1000	>1000	>1000	>1000

n..d.: not determined due to mathematical reasons or inappropriate data.

 

Table 5: Biological test results after 28 days of exposure

 

Parameters	Control	Solvent Control	Pooled Control	Nominal Test Item Concentration [mg/kg dry sediment]
				46	100	220	460	1000
Sum of Introduced Larvae	60	100	160	60	60	60	60	60
Sum of Emerged Adults	57	93	150	55	58	57	57	49
Emerged as % of Introduced	95	93	94	92	97	95	95	82
Emergence Ratio (Arcsin Transformed)	1.39	1.31	1.34	1.28	1.46	1.39	1.39	1.13
% of pooled control	-	-	-	96	109	104	104	84
Development Rate Females [day^-1]	0.060	0.059	0.060	0.058	0.056	0.055	0.055	0.057
% Inhibition compared to the pooled control	-	-	-	2.7	6.3	7.4	7.2	3.6
Development Rate Males [day^-1]	0.063	0.064	0.063	0.059	0.060	0.059	0.057	0.057
% Inhibition compared to the pooled control	-	-	-	6.2	5.6	6.7	9.4	9.5
Development Rate All [day-1]	0.062	0.062	0.062	0.059	0.058	0.057	0.056	0.057
% Inhibition compared to the pooled control	-	-	-	4.9	5.7	6.7	8.3	7.3

 

 

Validity criteria fulfilled:

yes

Conclusions:

The EC10 after 28 d was determined to be 847 mg/kg sediment dw for pooled sexes based on the emergence rate.

Executive summary:

An experimental study according to OECD guideline 218 and GLP regulations was conducted to assess the long-term toxicity of the test item to Chironomus riparius. The spiked water-sediments were kept for two days under the test conditions to reach equilibrium between sediment and aqueous phases as pore water and overlying water before the introduction of the first-instar larvae of Chironomus riparius. First-instar larvae were exposed for a period of 28 days until full maturation of the larvae to adult midges. The test parameters of the study were development time/rate of the midges and emergence ratio as the number of male and female fully emerged midges. The test item was applied to an artificial sediment in static water-sediment systems. The nominal initial test item concentrations, calculated as concentrations of the test item in the dry sediment, were 46, 100, 220, 460 and 1000 mg test item/kg dry sediment. In parallel, a control (water-sediment systems without test item) and a solvent control (sediment treated with acetone without test item) were tested. The analytically measured concentrations of C13-C15-Alcohol in the application solution samples ranged from 97 to 99 % of the nominal values. This confirmed the correct preparation of the application solutions.

 

The total recovery of the nominal amounts of applied test item found in the sediment immediately after application (Day-2) ranged from 93 % to 103 % in all tested concentrations. Thus, the correct application of the test item could be verified.

 

For the quantification of the test item concentrations in the three compartments water, pore water and sediment, the concentration of the test item was analytically determined in a medium and in the highest tested concentration (220 and 1000 mg test item/kg dry sediment).

 

During the equilibration (Day -2 to 0) and the test period (Day 0 to 28), the test item concentration in the three compartments decreased slightly. The total recovery of the nominal amounts of applied test item found in the three compartments ranged from 82 – 90 % at test start (Day 0). After 7 days of exposure the recovery was further decreased to 74 – 80 % and at test end after 28 days of exposure 48 – 70 % of the nominal concentration was detected.

No adverse effect on the developmental rate of female organisms and for pooled sexes was observed up to the highest tested concentration. Therefore, the EC10 for theses endpoints was determined to be >1000 mg/kg sediment dw. For male organisms the EC10 was 901 mg/kg sediment dw. The most sensitive endpoint was the emergence rate of pooled sexes with a EC10 of 847 mg/kg sediment dw (see table 4 and 5 for details). In conclusion, slightly adverse effects of the test item to Chironomus riparius  were observed  at the highest tested concentration based on the emergence rate.

Description of key information

The EC10 after 28 d was determined to be 847 mg/kg sediment dw for pooled sexes based on the emergence rate.

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater sediment:

847 mg/kg sediment dw

Additional information

An experimental study according to OECD guideline 218 and GLP regulations was conducted to assess the long-term toxicity of the test item to Chironomus riparius (BASF, 2022). The spiked water-sediments were kept for two days under the test conditions to reach equilibrium between sediment and aqueous phases as pore water and overlying water before the introduction of the first-instar larvae of Chironomus riparius. First-instar larvae were exposed for a period of 28 days until full maturation of the larvae to adult midges. The test parameters of the study were development time/rate of the midges and emergence ratio as the number of male and female fully emerged midges. The test item was applied to an artificial sediment in static water-sediment systems. The nominal initial test item concentrations, calculated as concentrations of the test item in the dry sediment, were 46, 100, 220, 460 and 1000 mg test item/kg dry sediment. In parallel, a control (water-sediment systems without test item) and a solvent control (sediment treated with acetone without test item) were tested. No adverse effect on the developmental rate of female organisms and for pooled sexes was observed up to the highest tested concentration. Therefore, the EC10 for theses endpoints was determined to be >1000 mg/kg sediment dw. For male organisms the EC10 was 901 mg/kg sediment dw. The most sensitive endpoint was the emergence rate of pooled sexes with a EC10 of 847 mg/kg sediment dw (see table 4 and 5 for details). In conclusion, slightly adverse effects of the test item to Chironomus riparius  were observed  at the highest tested concentration based on the emergence rate.