[No public or meaningful name is available]

Sediment toxicity

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

sediment toxicity: short-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Refer to analogue justification document provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

10 d

Dose descriptor:

LC50

Effect conc.:

8 643.55 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 7680.55 - 9422.5 mg/L

Remarks:

source, RA-A, CAS 91050-80-5, Emery, 2008, Corophium volutator, 10d

Duration:

10 d

Dose descriptor:

NOEC

Effect conc.:

1 553.04 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other:

Remarks:

source, RA-A, CAS 91050-80-5, Emery, 2008, Corophium volutator, 10d

Conclusions:

No effects were observed up to the limit of water solubility.

Reference 2

Endpoint:

sediment toxicity: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 Nov - 07 Dec 2007

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Basic data given (comparable to guidelines/standards)

Qualifier:

according to guideline

Guideline:

other: OSPARCOM guidelines (2005) A sediment Bioassay using an amphipod corophium sp

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

yes

Details on sediment and application:

PREPARATION OF SPIKED SEDIMENT
In order to determine an appropriate test preparation method, an assessment was made of its behaviour in seawater. 1000 mg/L of stock was prepared in filtered seawater, and the resulting mixture was stirred for approximately 4 hours. The mixture was then left to settle for approximately 1h, and its behaviour assessed (SOP 402). Test material preparation was conducted in accordance with SOP 403. Materials which were assessed to be poorly soluble were prepared by mixing initially with a small quantity of dry sediment, using a solvent of low toxicity such as acetone, ethanol or triethylene glycol if necessary. The dried sediment was then incorporated with the wet sediment (in the mixing container). The mixing vessels were then placed on a platform shaker at 150 rpm for 3 hours. After this period, the contents of each container were equally distributed between the replicate vessels, three for test concentrations and five for control vessels.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): acetone, ethanol or triethylene glycol

Test organisms (species):

Corophium volutator

Details on test organisms:

TEST ORGANISM
- Common name: amphipod
- Source: Bay of Suckquoy, Toab in Orkney
- Details on collection: Test organisms were collected on 22 November 2007 from a site in the Bay of Suckquoy, Toab in Orkney and received on site on 23 November 2007. Specimens were gently sieved from their native sediment and held in plastic containers (approximately 5L capacity) containing some ambient water, with a small amount of detritus, until transfer to the laboratory. On return to the laboratory, the Corophium were transferred in ambient water to polythene tanks of approximately 200 litre capacity, gentle aeration was supplied.
- Age of animals at beginning of exposure: Specimens of approximately 5 mm in body length (excluding rostrum) were used in the toxicity tests

ACCLIMATION
- Acclimation period: Acclimated to laboratory conditions for 4 days prior to testing.
- Acclimation conditions: The tanks were held in a controlled-temperature room at approximately 15 ± 2 °C. The stock animals were gradually acclimated from the ambient salinity of less than 5‰ to that of undiluted seawater (approximately 35‰) in increments of approximately 10‰ per day. Once acclimation is complete, the stock tanks were maintained under semi-static conditions until the initiation of the test. The holding period in the laboratory is between 3 and 14 days. Sufficient detrital material is retained in each tank to provide food and some bottom cover, but not of a density that prevents daily observation of mortality and morbidity. Dead or impaired animals are removed when observed.

Study type:

laboratory study

Test type:

semi-static

Water media type:

saltwater

Type of sediment:

natural sediment

Limit test:

no

Duration:

10 d

Exposure phase:

total exposure duration

Test temperature:

14.1 – 15.1 °C

pH:

8.09 – 8.31

Dissolved oxygen:

93 – 98%

Salinity:

33 – 38

Nominal and measured concentrations:

100, 320, 1000, 3200, and 10000 mg/kg (nominal)
160.77, 504.54, 1553.04, 4826.85, and 14113.23 (calculated mg/kg sediment dw)

Details on test conditions:

TEST SYSTEM
- Test container (material, size): 1 litre capacity glass beakers
- Sediment volume: approximately 150 mL
- Overlying water volume: 850 mL overlying seawater
- Depth of sediment and overlying water: 2 cm sediment
- Aeration: yes, stream of air bubbles were released at a depth of approximately 6 cm

EXPOSURE REGIME
- No. of organisms per container (treatment): 20
- No. of replicates per treatment group: 3
- No. of replicates per control: 5

OVERLYING WATER CHARACTERISTCS
- Type of water (e.g. deionized, ground water, sea water, Elendt medium acc. to OECD 219): 1 µm filtered ultra violet treated seawater
- Source of water (if non-standard medium): Seawater for testing was supplied by pump from Scapa Flow, Orkney

SOURCE OF NATURAL SEDIMENT
- Location and description of sampling site: collected on 22 November 2007 from a site in the Bay of Suckquoy, Toab in Orkney and received on site on 23 November 2007, acclimated to laboratory conditions for 4 days prior to testing.

HANDLING OF NATURAL SEDIMENT
- Time of collection: 22 November 2007. On return to the laboratory, the sediment was wet-sieved through 0.6 mm mesh to remove larger infaunal
organisms and Corophium within the test size range, and allowed to settle in tall polyethylene containers. After settling, the supernatant water was decanted and the sediment stored
- Storage conditions: at approximately 4 ± 2 °C, until required for testing.

Particle size analysis characterised the sediment aswell-sorted, fine sand with a silt/clay content of 3.56% by weight. Median particle diameter was 151 µm. The organic material content was estimated from weight loss on ignition to be 1.34%. Immediately before the initiation of the test, the sediment was thoroughly homogenised and a representative sample taken for wet and dry weight determination. The ratio of wet weight to dry weight
was subsequently used to convert nominal exposure concentrations on a wet weight basis to nominal exposure concentrations on a dry weight basis.

OTHER TEST CONDITIONS
- Photoperiod: constant dim illumination
- beakers covered with a rectangular sheet of perspex perforated with a small hole above the centre of each beaker

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

VEHICLE CONTROL PERFORMED: no

Reference substance (positive control):

no

Duration:

10 d

Dose descriptor:

LC50

Effect conc.:

8 643.55 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 7680.55 - 9422.5 mg/L

Duration:

10 d

Dose descriptor:

NOEC

Effect conc.:

1 553.04 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Reported statistics and error estimates:

The number of animals responding after 10 days in each replicate are expressed as a proportion of the nominal number exposed (20). The 10 day LC50, LC90and NOEC values are calculated using an appropriate statistical method from the ToxCalc Version 5 software.

The wet to dry ratio of sediment used in this study was 1.61 and this was used to correct nominal wet sediment concentrations to nominal dry sediment concentrations.

Table: Calculated nominal exposure concentrations and observed mortality after 10 days

	Treatment (mg/kg dry weight)	Mortality (proportion dead)			Raw mean
Test material	160.77	0.00	0.00	0.05	0.02
	504.54	0.05	0.10	0.15	0.10
	1553.04	0.05	0.00	0.00	0.02
	4826.85	0.10	0.15	0.25	0.17
	14113.23	1.00	1.00	1.00	1.00

Description of key information

LC50 (10 d) = 8643.55 mg/kg sediment dw (OSPARCOM, Corophium volutator); read-across

 

Additional information

No experimental data evaluating the toxicity to sediment organisms are available for Fatty acids, C16-18 (even numbered), esters with glycerol oligomers. Therefore, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read-across to the structurally related source substance Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol] (CAS 91050-80-5) was performed in accordance with Regulation (EC) No 1907/2006 Annex XI, section 1.5 in order to fulfill the data requirements for this substance. The source substance is characterized by similar chemical structure and is therefore considered as suitable representative for the assessment of the toxicity of the target substance to microorganism.A detailed read-across justification in provided in IUCLID section 13.

One experimental marine study investigating the toxicity of the source substance Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol] (CAS 91050-80-5) to Corophium volutator was conducted according to OSPARCOM (2005) under GLP conditions. Corophium volutator was exposed to five nominal concentration between 100 and 10000 mg/kg sediment dw with natural sediment in a semi-static test for 10 days.An LC50 (10 d) of 8643.55 mg/kg sediment dw was derived.

In addition, all reliable aquatic acute (fish, invertebrates, algae) and aquatic chronic data (invertebrates, algae) for the target substance and suitable source substances indicate no effects up to the water solubility limit.

Furthermore, the substance is considered readily biodegradable (94% biodegradation after 28 days; read-across) confirmed with QSAR calculations for representative constituents (VEGA (1.1.4); Ready Biodegradability Model (v1.0.9). Thus, it is expected that an extensive elimination of the substance in sewage treatment plants will occur.

According to the Guidance on Information Requirements and Chemical Safety Assessment, Chapter R.7b (ECHA, 2017), the ready biodegradability of a substance can be considered indicative of rapid and ultimate degradation in most environments, including biological sewage treatment plants (STP) where the substance will be extensively removed in the primary settling tank and fat trap. As a result of the high adsorption potential of the substance (log Koc = 1.31 – 12.67, KOCWIN v2.00; MCI method), a removal from the water column to a significant degree by adsorption to sewage sludge can be expected (Guidance on information requirements and chemical safety assessment, Chapter R.7b, (ECHA, 2017)). Thus, only limited amounts will get in contact with activated sludge organisms in STPs and the concentration of the substance in effluents of conventional STPs is presumably marginal. Therefore, discharged concentrations of these substances into the aqueous/sediment compartment are likely to be negligible.Considering this, one can assume that the availability of for Fatty acids, C16-18 (even numbered), esters with glycerol oligomers in the sediment environment is very low, which reduces the probability of exposure of sediment organisms in general.

Nevertheless, once present in the aquatic compartment the substance will mainly partition to the sediment particles due to the low water solubility and high adsorption potential. Thus, the substance will be bioavailable to sediment organisms mainly via feed and contact with suspended organic particles. The results of the read across substance show no toxicity up to the water solubility to sediment organisms.

Moreover, the bioaccumulation potential is low. Based on the physico/chemical properties such as poor water solubility and high potential for adsorption a reduced availability in water is expected. In addition, the available literature data showed that soil microorganisms are capable to break-up ester bonds and degrade fatty acids in significant amounts. Moreover, the data indicated the non-toxic properties of fatty acids since they can be used as energy source. It can be concluded that the bioaccumulation potential of Fatty acids, C16-18 (even numbered), esters with glycerol oligomers is negligible. This is supported by a low calculated BCF value ranged from 0.94 - 18.58L/kg ww (BCFBAF v3.01, Arnot-Gobas, including biotransformation, upper trophic).With VEGA 1.1.3 BCF values of 0.74 - 2 L/kg were determined (Caesar v2.1.14) for the main components of the substance. Therefore, for Fatty acids, C16-18 (even numbered), esters with glycerol oligomers is unlikely to pose a risk for sediment organisms and further testing is thus omitted.

Based on the available results in a sediment toxicity study from a structurally related read-across substance (in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5) which is characterized by a similar ecotoxicological profile and comparable structure, an extensive elimination of the substance in sewage treatment plants, a low bioavailability and low bioaccumulation potential, it can be concluded that the target substance Fatty acids, C16-18 (even numbered), esters with glycerol oligomers is not expected to show toxicity to sediment organisms up to the limit of its water solubility (91.9 µg/L).