2-Ethylhexyl trans-4-methoxycinnamate

Sediment toxicity

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

purity of test item not specified, use of solvent not justified, preparation of treatments not sufficiently described, number of test animals per treatment not reported, artificial sediment differed from standard artificial sediment used in OECD TG 225 and 218 (less complex), test conditions not sufficiently reported, analytical method not reported, no information on homogeneity of test item in sediment, acclimatization not reported, feeding not in line with guideline, validity criterial according to guideline not confirmed

Qualifier:

according to guideline

Guideline:

OECD Guideline 225 (Sediment-Water Lumbriculus Toxicity Test Using Spiked Sediment)

Version / remarks:

2007

Deviations:

yes

Remarks:

sediment contained 99.6% pure quartz sand (grain size 0.1e0.4, Quick Mix group, Osnabrück, Germany) and 0.4% grounded alder leaves (Alnus glutinosa)

GLP compliance:

not specified

Remarks:

GLP-compliance not reported

Analytical monitoring:

yes

Details on sampling:

not specified

Vehicle:

yes

Remarks:

ethyl acetate

Details on sediment and application:

not specified

Test organisms (species):

Lumbriculus variegatus

Details on test organisms:

TEST ORGANISM
- Common name: blackworm
- Source: not specified
- Breeding conditions: held in 5 L aquaria with reconstituted water; pH-value: 7.9 to 8.4, conductivity 500 to 600 µS/cm), 16 °C, 16:8 h (light/dark)
- Feeding during test: yes
- Food type: TetraMin (Tetra GmbH, Melle, Germany)
- Amount: ad libitum
- Frequency: once a 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:

total exposure duration

Hardness:

not specified

Test temperature:

16 °C

pH:

7.9 to 8.4

Dissolved oxygen:

not specified

Salinity:

not applicable

Ammonia:

not specified

Conductivity:

500 to 600 µS/cm

Nominal and measured concentrations:

Nominal: 0.08, 0.4, 2,10 and 50 mg/kg dw sediment; measured concentrations not available

Details on test conditions:

TEST SYSTEM
- Test container: aquaria (5 L)
- Depth of sediment and overlying water: 1 cm

EXPOSURE REGIME
- No. of replicates per treatment group: 4
- No. of replicates per control / vehicle control: 4
- Feeding regime: once per week ad libitium
- Type and preparation of food: TetraMin (Tetra GmbH, Melle, Germany)

OVERLYING WATER CHARACTERISTCS
- Type of water: reconstituted water

CHARACTERIZATION OF ARTIFICIAL SEDIMENT
- Composition: 99.6 % pure quartz sand (grain size 0.1 - 0.4, Quick Mix group, Osnabrück, Germany) and 0.4 % grounded alder leaves (Alnus glutinosa)

OTHER TEST CONDITIONS
- Photoperiod: 16:8 light:dark

EFFECT PARAMETERS MEASURED: biomass and number of worms per replicate after 28 days

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Range finding study: performed
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

no

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 50 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: no significant effect observed up to and including the highest concentration tested

Details on results:

The lowest reproduction average of 42 individuals at 50 mg/kg EHMC was not significantly lower than in the control. The number of worms increased slightly between 0.08 and 2 mg/kg and decreased again to control level in the two highest exposure groups.

Results with reference substance (positive control):

not tested

Table 1: Nominal and measured test concentrations of EHMC at the beginning and the end (in brackets) of the sediment tests with Lumbriculus variegatus  (C = control; SC = solvent control; n.d. = not detectable; - = not tested or not measured).

Nominal concentration [mg/kg dw]	Measured concentration [mg/kg dw]
C	n.d. (n.d.)
SC	n.d. (n.d.)
0.00064	-
0.016	-
0.08	0.01 (0.01)
0.4	-
50.0	33.4 (30.9)

Validity criteria fulfilled:

not specified

Conclusions:

In a sediment-water test with L. variegatus using spiked sediment the 28d-NOEC of the test item was determined to be >= 50 mg/kg sediment dw (nominal). However these results were regarded as not reliable for reasons as stated above.

Executive summary:

The effect of the test item to Lumbriculus variegatus was assessed in a 28-day sediment-water toxicity according to OECD TG 225. As a result, the lowest reproduction average of 42 individuals at 50 mg/kg EHMC was not significantly lower than in the control. The number of worms increased slightly between 0.08 and 2 mg/kg and decreased again to control level in the two highest exposure groups. Therefore, the 28d-NOEC was determined to be  ≥ 50 mg/kg sediment dw (nominal).

Reference 2

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

purity of test item not specified, use of solvent not justified, preparation of treatments not sufficiently described, number of test animals per treatment not reported, artificial sediment differed from standard artificial sediment used in OECD TG 218 (less complex), test conditions not sufficiently reported, analytical method not reported, no information on homogeneity of test item in sediment, acclimatization not reported

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

2004

Deviations:

yes

Remarks:

sediment contained 99.6% pure quartz sand (grain size 0.1e0.4, Quick Mix group, Osnabrück, Germany) and 0.4% grounded alder leaves (Alnus glutinosa)

GLP compliance:

not specified

Remarks:

GLP-compliance not reported

Analytical monitoring:

yes

Details on sampling:

not specified

Vehicle:

yes

Remarks:

ethyl acetate

Details on sediment and application:

not specified

Test organisms (species):

Chironomus riparius

Details on test organisms:

Source: laboratory culture

Study type:

laboratory study

Test type:

static

Water media type:

freshwater

Type of sediment:

artificial sediment

Limit test:

no

Duration:

28 d

Exposure phase:

total exposure duration

Hardness:

not specified

Test temperature:

20 +/- 1 °C

pH:

not specified

Dissolved oxygen:

not specified

Salinity:

not applicable

Ammonia:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

Nominal: 0.08, 0.4, 2,10 and 50 mg/kg dw sediment; for measured concentrations see "Any other information on materials and methods incl. tables"

Details on test conditions:

TEST SYSTEM
- Test container (material, size): not specified
- Depth of sediment: 1 cm

EXPOSURE REGIME
- No. of replicates per treatment group: 4
- No. of replicates per control / vehicle control: 4
- Feeding regime: acc. to guideline

OVERLYING WATER CHARACTERISTCS
- Type of water: reconstituted water

CHARACTERIZATION OF ARTIFICIAL SEDIMENT
- Composition: 99.6 % pure quartz sand (grain size 0.1 - 0.4, Quick Mix group, Osnabrück, Germany) and 0.4 % grounded alder leaves (Alnus glutinosa)

OTHER TEST CONDITIONS
- Photoperiod: 16:8 light:dark

EFFECT PARAMETERS MEASURED: mortality, number of produced clutches, number of eggs per egg mass, mean emergence time (EmT50) and sex ratio after 28 days

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Range finding study: performed
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

no

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 50 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: number of eggs per egg mass

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 50 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

sex ratio

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 50 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: emergence time

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 50 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: number of produced clutches

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 50 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

The mortality was below 10 % in all treatment groups and no significant effects were detected.

Table 1: Nominal and measured test concentrations of EHMC at the beginning and the end (in brackets) of the sediment tests with Chironomus riparius. (C = control; SC = solvent control; n.d. = not detectable; - = not tested or not measured).

Nominal concentration [mg/kg dw]
	C. riparius
C	n.d. (n.d.)
SC	n.d. (n.d.)
0.00064	-
0.016	-
0.08	0.04 (0.04)
0.4	-
50.0	46.4 (40.8)

Validity criteria fulfilled:

not specified

Conclusions:

In a 28-day sediment-water Chironomid toxicity test according to OECD TG 218 with C. riparuis using spiked sediment the 28d-NOEC of the test item was determined to be ≥ 50 mg/kg sediment dw (nominal).
However, due to several short comings wrt to methodolgy and deviations to the OECD Guideline 218 as described in the endpoint summary, the results of this study were regarded as not reliable.

Executive summary:

The effect of the test item to Chironomus riparius was assessed in a 28-day sediment-water Chironomid toxicity test according to OECD TG 218 using spiked sediment. As a result, the mortality was below 10 % in all treatment groups and no significant sublethal effects were detected. Therefore, the 28d-NOEC was determined to be ≥ 50 mg/kg sediment dw (nominal).

Description of key information

The available experimental information is considered not reliable (Klimisch 3). Therefore, a Sediment-Water Lumbriculus Toxicity Using Spiked Sediment according to OECD TG 225 is planned to be conducted. Depending on the results of the OECD 225 Study, a Sediment-Water Chironomid Toxicity Using Spiked Sediment according to OECD TG 218 will be conducted subsequently. The dossier and the risk assessment will be updated as soon as new and reliable study data are available.

Additional information

Experimental data on the toxicity of 2-ethylhexyl trans-4-methoxycinnamate (OMC, also known as EHMC) to the freshwater sediment organisms Lumbriculus variegatus, Chironomus riparius, Potamopyrgus antipodarum and Melanoides tuberculate as well as Danio rerio were published by Kaiser et al. (2012).

A 56 day sediment test with the gastropod Potamopyrgus antipodarum was performed following the method described in Duft et al. (2007). The test with M. tuberculata was not performed according to an official and internationally accepted guideline. A sediment contact test with Danio rerio was carried out according to the German guideline DIN 38415-6. In addition, the methods given in Nagel (2002) and Lammer et al. (2009) were applied. The toxicity of EHMC towards Lumbriculus variegatus and Chironomus riparius was assessed according to OECD TG 225 (modified) and OECD TG 218, respectively. 

However, after detailed evaluation of the methodology and testing design, the testing results on EHMC are considered not reliable and are thus not regarded suitable for the sediment risk assessment. Several shortcomings in the test design and documentation of the various tests were identified and are summarized below.

 

General considerations on the validity of the available experimental data
In general, no information on purity and impurities is provided. Further, it is not clear why ethyl acetate was used as a solvent in the tests with invertebrates and the preparation of the respective treatments is not sufficiently described. For the invertebrate testing the number of test animals per treatment is not reported. In the tests with Lumbriculus variegatus and Chironomus riparius, the artificial sediment differed from standard artificial sediment used in OECD TG 225 and 218 (less complex). Therefore the results obtained in these tests are difficult to compare with other results. Important monitoring of water quality parameters like pH and the dissolved oxygen content in overlying water are not described. In addition, analytical monitoring was performed, but the method is not reported and it is not stated if the treatment homogeneity in sediment was provided, as required by the applied test guidelines OECD 225 and OECD 218. It is further not specified whether the test animals were acclimatized. In sum, the reporting for these studies is not comprehensive and not in compliance with reporting criteria of the guideline.
In the following additional shortcomings of the assays with L. variegatus and M. tuberculata are pointed out.

 

Sediment-Water Toxicity Test with Lumbriculus variegatus
In this test the artificial sediment also differed between culture (pure quartz sand) and testing (sediment composition based on natural lakes incl. organic carbon). Kaiser et al. (2012) reported that test animals were “fed once a week ad libitum with TetraMin”. However, according to the applied OECD TG 225 feed should be added to the artificial sediment before test start. The test item concentrations were determined to be 66.8% of nominal for the highest treatment, the lowest concentration was found to be 12.5% of nominal. Finally, it is not clear whether the validity criteria of the guideline were met.

 

Toxicity test with M. tuberculata
The assay was not performed according to an official test guideline. Neither information about the purity of the test substance nor the mode of application reported is reported. It is not clear from the publication whether a solvent was used. Further, water quality parameters, e.g. nitrite, nitrate and ammonium concentration throughout the test, are not specified. This represents an important information gap because as gastropods are known to be highly sensitive towards increasing nitrogen levels. Moreover, the test animals originated from a wildcought, but the health status of the animals is not specified. Further, from the supplemental information it is not obvious if the measured test item concentrations refer to an exposure duration of 28 or 56 days. In addition, the number of replicates is not stated and standard deviations are not provided.

 

 

Conclusion

Taken together, the available experimental data on the toxicity of EHMC to sediment organisms is considered not reliable (Klimisch 3) due to significant methodological deficiencies and insufficient documentation. The data bear thus several uncertainties and were not considered for the risk assessment.

Instead, concerns regarding the sediment compartment shall be dispelled by new state-of-the-art and GLP-compliant guideline studies suitable to assess the toxic potential of EHMC to sediment organisms.

Hence, a Sediment-Water Lumbriculus Toxicity Using Spiked Sediment according to OECD TG 225 will be conducted and depending on the results of the OECD TG 225 study a Sediment-Water Chironomid Toxicity Using Spiked Sediment according to OECD TG 218 will be conducted subsequently. The dossier and the risk assessment will be updated as soon as new and reliable study data are available.