7,7-dimethyl-3-oxa-6-azaoctan-1-ol

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:

Exposures were conducted between the 16th May and 26th May 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted in accordance with generally accepted scientific principles, possibly with incomplete reporting or methodological deficiencies, which do not affect the quality of relevant results.

Qualifier:

equivalent or similar to guideline

Guideline:

other: Test was performed based on the Paris Commision Guideline "MAFF/ERT Harmonised Protocol. A sediment bioassay using an amphipod Corophium sp."

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

not required

Details on sampling:

Please see details on test conditions.

Vehicle:

no

Details on sediment and application:

Test conditions: Three replicates were prepared for each test material concentration and five replicates for the control. The volume (800 ml) of overlying artificial seawater was maintained throughout the study by addition of water purified by reverse osmosis to compensate for water lost by evaporation. Test organisms were added to the spiked and control sediments at a density of 20 per vessel.

Test organisms (species):

Corophium volutator

Details on test organisms:

A batch of amphipods freshly dug from the Anglesey coast, free of malformation and of good health, were obtained on the 3rd May 1996 and assigned a batch number of CV960010.
Stock amphipods were held in 13 litre storage vessels on sieved sediment/detritus obtained from the collection site.

Study type:

laboratory study

Test type:

static

Water media type:

saltwater

Type of sediment:

natural sediment

Limit test:

no

Duration:

10 d

Exposure phase:

total exposure duration

Post exposure observation period:

Not applicable.

Hardness:

Not recorded.

Test temperature:

Temperature was measured at intervals for the aqueous medium in each test vessel.
Temperature recorded: 14.8 - 15.1ºC (see appendix 3)

pH:

pH was measured at intervals for the aqueous medium in each test vessel.
pH recorded: 8.14 - 8.40 (see appendix 2)

Dissolved oxygen:

Dissolved oxygen values were measured at intervals for the aqueous medium in each test vessel.
Recorded values: 97.7 - 98.8 mg kg-1 (see appendix 1)

Salinity:

Artificial seawater with a salinity of 30.5 g/l

Ammonia:

Not recorded.

Nominal and measured concentrations:

Five (nominal) concentrations at 100, 316.2, 1000, 3162.3 and 10000 mg/kg

Details on test conditions:

Dilution media: Artificial seawater (Tropical Marine, Germany) with salinity of 30.5 g/l and natural sediment obtained from the site of collection of the test organisms.

Test vessels: Tall form glass beakers, 1 litre capacity.

Test concentrations: Five concentrations at 100, 316.2, 1000, 3162.3 and 10000 mg/kg expressed as dry weight of sediment together with an untreated control were prepared. Aliquots of the test substance were added to 100 ml of artificial seawater. This was added to the wet sediment and mixed. Untreated controls were prepared in a similar way without the addition of test material.

Test conditions: Three replicates were prepared for each test material concentration and five replicates for the control. The volume (800 ml) of overlying artificial seawater was maintained throughout the study by addition of water purified by reverse osmosis to compensate for water lost by evaporation. Test organisms were added to the spiked and control sediments at a density of 20 per vessel.

Photoperiod: Ambient laboratory lighting.

Aeration: Air bubbled directly into artificial seawater via polypropylene tubing.

Observations: Test organisms were observed at intervals during the 10 days of the study with regard to swimming, behavior and mortality. At the end of the study the sediment was re-suspended and sieved and the mortality data were recorded.

Death criterion: Organisms which became opaque and were lying on the surface of the sediment during the study were recorded as mortalities. Organisms exhibiting no movement and failing to respond to tactile stimulus at the end of the study were recorded as mortalities.

Reference substance (positive control):

no

Duration:

10 d

Dose descriptor:

LC50

Effect conc.:

> 10 000 mg/kg sediment dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: The 95% confidence range could not be determined.

Details on results:

The LC50 was found to be > 10000 mg/kg dry weight of sediment. There was an indication of dose response only at the highest concentrations.

The highest concentration of test material producing no observable effect was determined to be 3162.3 mg/kg, this being the highest concentration giving a mortality value below or equal to the acceptable normal distribution of control mortality (0-20%). None of the concentrations tested produced 100% mortality.

Amphipods at all concentrations tested, reached the sediment surface within 5 minutes of addition to the test vessels.

The pH values at day 0 for the highest concentration (10000 mg/kg dry sediment) of test material were outside the validity criteria, however, this was not thought to have significantly affected the final result.

Results with reference substance (positive control):

Not applicable.

Reported statistics and error estimates:

The mortality data calculated at each observation period would normally be processed by a computer program using probit analysis, supplied by the National Swedish Environmental Protection Agency, to derive the median effect concentration (LC50) which killed 50% of the animals exposed to the test material together with 95% confidence limits. However, in this instance the data was inappropriate for such analysis.

From the mortality data observed under these test conditions (Table 1 and Appendix 4) after 10 days exposure to the test material, an LC50 of >10000 mg/kg dry weight of sediment was found (Table 2).

Table1: Cumulative percentage mortality (%) data.

Concentration mg kg^-1	Observed mortalities (%)
0	10.0
100	13.3
316.2	15.0
1000	10.0
3162.3	15.0
10000	48.3

Table 2: Toxicity data

Time (days)	LC50 mg kg^-1	95% Confidence limits	Slope function	Regression	Degrees of freedom	Probability (%)
10	>10,000	-	-	-	-	-

See attached background material for Appendix 1 -4.

Validity criteria fulfilled:

yes

Conclusions:

From this study the ten day LC50 value was found to be >10,000 mg kg-1 dry weight of sediment.

Executive summary:

The Corophium volutator sediment reworker test was performed on the test substance based on the Paris Commision Guideline "MAFF/ERT Harmonised Protocol. A sediment bioassay using an amphipod Corophium sp."

The 10 day LC50 value for the test substance was found to be >10,000 mg/kg (dry weight) of sediment. The 95% confidence range could not be determined.

The sediment reworker is not included in any ecotoxicological classification system.

Description of key information

The Corophium volutator sediment reworker test was performed on the test substance based on the Paris Commision Guideline "MAFF/ERT Harmonised Protocol. A sediment bioassay using an amphipod Corophium sp."
The 10 day LC50 value for the test substance was found to be >10,000 mg/kg (dry weight) of sediment. The 95% confidence range could not be determined.

Key value for chemical safety assessment

EC50 or LC50 for marine water sediment:

10 000 mg/kg sediment dw