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Ecotoxicological information

Sediment toxicity

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Administrative data

Endpoint:
sediment toxicity: long-term
Type of information:
experimental study planned
Remarks:
An OECD Guideline 225 study is currently ongoing
Study period:
Study currently ongoing (expected completion date: 2020)
Justification for type of information:
An experimental study is currently ongoing (according to OECD Guideline 225) to assess the effects of Trioctyl benzene-1,2,4-tricarboxylate on the endobenthic oligochaete, Lumbriculus variegatus. Available study details from the current version of the study plan are reported and the robust study summary will be updated when the final study report becomes available.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2020

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 225 (Sediment-Water Lumbriculus Toxicity Test Using Spiked Sediment)
Version / remarks:
2007
Deviations:
not specified
Remarks:
Study is currently ongoing
Principles of method if other than guideline:
Study was conducted according to a standard guideline
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Specific details on test material used for the study:
Batch No.: 1190
Expiry date: 23 May 2020
Analysed purity content: 100%
Substance type: Technical product
Appearance: Slight yellowish transparent liquid
Storage conditions: Ambient temperature (room temperature, dark and dry, GLP-storage room)

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
To verify exposure concentrations, sediment samples, pore water and overlying water samples were taken at test start and test end. A stock solution sample was also taken at sediment preparation (at the start of the equilibration phase). Porewater was gained by centrifugation at 10000 x g for at least 30 minutes and up to a maximum of 60 minutes if necessary. Samples for analysis were sent for analysis or immediately frozen after sampling. Samples were stored at ≤-18°C until analysis. Retained samples which were not needed were disposed after the finalisation of the study.

Test substrate

Vehicle:
yes
Remarks:
0.01% acetone
Details on sediment and application:
The test item was applied using spiked sediment. Individual stock solutions for each treatment group were prepared and mixed into a defined proportion of dry sand. Stock solutions and their dilutions were prepared in acetone. Acetone was allowed to fully evaporate over a two hour period and the dry sand subsequently mixed into wet sediment. Untreated controls and solvent controls which did not contain test item were included in the study design. Wet sediment was prepared approximately seven days before test start. Two days before test start, spiked sediment was prepared, introduced into test vessels, overlaid with test medium and incubated under test conditions with gentle aeration. Tests were started upon the introduction of synchronised worms to the spiked sediment.

Test organisms

Test organisms (species):
Lumbriculus variegatus
Details on test organisms:
Test organism origin: ECT Oekotoxikologie GmbH, Böttgerstraße 2 – 14, 65439 Flörsheim am Main, Germany
Origin of animals used in testing: Holding and breeding in the test facility under standardised laboratory conditions
Breeding: Performed in glass beakers (250 mL) under the same conditions as in the test
Breeding medium: Reconstituted water (according to OECD Guideline 203)
Food and feeding (breeding): Twice a week with commercial fish food (Tetra Min)
All test organisms were derived from a synchronised culture.

Study design

Study type:
laboratory study
Test type:
static
Water media type:
freshwater
Type of sediment:
artificial sediment
Remarks:
Reconstituted water was used as overlying water. Sediment contained powdered leafs of stinging nettle (Folia urticae) as a food source.
Limit test:
no
Exposure duration
Duration:
28 d
Exposure phase:
total exposure duration
Post exposure observation period:
N/A

Test conditions

Hardness:
90 – 300 mg/L CaCO3
Test temperature:
20 ± 2°C
pH:
6 - 9
Dissolved oxygen:
Currently not reported (will be updated when final report becomes available)
Salinity:
N/A
Ammonia:
Currently not reported (will be updated when final report becomes available)
Conductivity:
≤10 µS/cm (according to OECD Guideline 203)
Nominal and measured concentrations:
Nominal test item concentrations: 0 (untreated control), 0 (solvent control), 42.69, 93.91, 206.61, 454.55, 1000 mg/kg dry weight
Details on test conditions:
Tests were conducted using glass beakers (250 mL) as test vessels, with 10 worms test vessel and a sediment loading of 1:4 (sediment depth to the depth of overlying water). Freshly prepared test vessels including spiked sediment were equilibrated for two days under identical test conditions prior to test start. Tests included six replicates for control groups (untreated and solvent controls) and three replicates for treatment groups.

Tests were conducted under a 16:8 h (light:dark) photoperiod, with light intensity of 100 – 500 lux (~15-20 μE•m-2•s-1). Oxygen concentration and pH was monitored in one test vessel of each treatment and control group once per week, at test start and at test end. Test vessels were gently and constantly aerated throughout the test. Total water hardness (CaCO3) was assessed in one control vessel and one vessel of the highest treatment group at test start and at test end. Ammonium concentration (mg/L NH4+) was monitored in one test vessel of each treatment group and control 3 times per week.

At the end of testing each replicate was examined, and worms were sieved from sediment, and the total number of living and dead individuals per replicate and biomass (dry weight) recorded. Worms were considered dead if (1) they did not react after gently stimulus; (2) they showed signs of decomposition and (3) if worms are missing. Additionally, the general condition of single individuals, any abnormal behaviour of worms and/or abnormal appearance of sediment/overlying water were recorded. To assess dry weight, living worms were pre-weighed, killed using ethanol and transferred into a drying oven (at 100 ± 5°C over night).

Effect concentrations (ECx, LOEC, NOEC) were calculated for dry biomass, total number of worms, increase in worm number and increase in dry biomass. Mortality was also evaluated, despite not being a primary endpoint for this test. Probit analysis was applied to calculate ECx values. Normal distribution and variance homogeneity of data was tested using Shapiro-Wilk tests and Leven’s test, respectively. If the criteria of normal distribution are fulfilled, t-tests were applied to determine LOEC’s. Statistical analysis was performed using ToxRat Professional (RATTE, 2018).
Reference substance (positive control):
not specified
Remarks:
Will be updated when the final study report becomes available

Results and discussion

Effect concentrationsopen allclose all
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
206 mg/kg sediment dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Duration:
28 d
Dose descriptor:
NOEC
Effect conc.:
168 mg/kg sediment dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Details on results:
Will be updated when the final study report becomes available
Results with reference substance (positive control):
Will be updated when the final study report becomes available
Reported statistics and error estimates:
Will be updated when the final study report becomes available

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Remarks:
Will be updated when the final study report becomes available
Conclusions:
The study is currently ongoing, however provisional EC10 and NOEC values of 206 and 168 mg/kg sediment dry weight, respectively, are available based on numbers of juvenile worms. The conclusions of the study will be updated when the final study report becomes available.
Executive summary:

Will be updated when the final study report becomes available