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Endpoint:
sediment toxicity: long-term
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 218 (Sediment-Water Chironomid Toxicity Test Using Spiked Sediment)
Deviations:
not specified
Principles of method if other than guideline:
Not applicable
GLP compliance:
no
Analytical monitoring:
yes
Details on sampling:
SEDIMENT
- Natural stream sediments used in developmental assays were collected from a pristine site in Rapid Creek, South Dakota, and contained no detectable levels of test materials, pesticides or heavy metals as determined by GC and atomic adsorption spectrophotometric analyses.
- The particle size distribution was determined to be: clay (71 %), fine silt (19 %) and medium (40 %) and fine sands (6 %). The organic carbon content of the test sediments was 4.2 % prior to testing.

Vehicle:
no
Details on sediment and application:
No data
Test organisms (species):
Chironomus riparius
Details on test organisms:
TEST ORGANISM
- Common name: Fresh water midge
- Source: Reared in 10-gallon tanks with screened tops, containing 4 gallons of aerated well water replenished at a rate of approximately 2 L/h.
- Age of animals at beginning of exposure: 10 to 14 d posthatch
- Breeding conditions: Midges used in this study were reared in 10-gallon tanks, with screened tops, containing 4 gallons of aerated well water replenished at a rate of 2 L/hr. Two inches of natural stream sediment served as substrate in culture chambers. Midge cultures (and test organisms) were fed a mixed diet of Ralston-Purina trout chow-dehydrated alfalfa (5:1, w/w). This was supplemented with commercial dog treats at a rate adjusted to prevent fouling. Cultures were maintained at 22± 2 ° C. Water hardness was 150 mg/L as CaCO3, pH ranged 7.8 to 8.4, and there was a 16:8 h photoperiod (400 ft-c).
- Food type: Mixed diet of Ralston-Purina trout chow dehydrated alfalfa (5: 1, w/w). This was supplemented with commercial dog treats
- Age of animals at beginning of exposure: 1-2 d

ACCLIMATION
- Acclimation period: Not reported. However, midges were obtained in-house, cultured under the same conditions as the test.
- Acclimation conditions (same as test or not): Same
- Type and amount of food: See description of culture above.

Study type:
laboratory study
Test type:
other: Semistatic (Egg hatchability) & Flow through (Chronic assay)
Water media type:
freshwater
Type of sediment:
natural sediment
Limit test:
no
Duration:
24 d
Exposure phase:
total exposure duration
Remarks:
Chronic assay
Post exposure observation period:
Not reported
Hardness:
150 mg/L as CaCO3
Test temperature:
22±2 °C
pH:
7.8-8.4
Dissolved oxygen:
Not reported
Salinity:
Not reported
Ammonia:
Not reported
Nominal and measured concentrations:
The publication does not provide the nominal test concentrations. Instead, only the measured concentrations are available.
Egg hatchability: Measured concentration: 0.0, 2.6, 4.4, 7.8, 10.7, 14.4, 21.5 mg/L
Details on test conditions:
TEST SYSTEM
- Test container (material, size): 13 W x 25 L x 18 H cm dimensions chamber (chronic assay); 50 mL Cylindrical test chamber with Nitex® bottom ( Hatchability);
- Weight of wet sediment with and without pore water: 350 g sediment (dry weight equivalent) per test chamber; Wet sediment was autoclaved for 40 to 60 min before testing.


EXPOSURE REGIME (Egg hatchability)
- No. of organisms per container (treatment): 20 eggs in a loop
- No. of replicates per treatment group: Duplicate
- No. of replicates per control / vehicle control: Duplicate
- Feeding regime: Fed each day following water replenishment


EXPOSURE REGIME (Chronic assay)
- No. of organisms per container (treatment): 20 larvae per chamber
- No. of replicates per treatment group: Single
- No. of replicates per control / vehicle control: Single
- Feeding regime: Each food formulation daily
- Amount of food: 1 mL

RENEWAL OF OVERLYING WATER
- Details on volume additions:
Egg hatchability test: Replenished daily by trickling 150 mL directly into each test chamber and allowing excess volume from the overflow beaker to drain.
Chronic test: flow-through design; details on renewal not provided.


OVERLYING WATER CHARACTERISTCS:
- Type of water: Blend of deionized, reverse osmosis water and well water with a hardness of approximately 150 mg/L as CaCO3.This “blended” water, a mixture of deionized and well water, is often used in environmental testing at P&G. The details are not provided in the publication, but this water has been well characterized.


SOURCE OF NATURAL SEDIMENT
- Location and description of sampling site: Pristine site in Rapid Creek, South Dakota
- Contamination history of site: Contained no detectablelevels of test materials, pesticides or heavy metals

CHARACTERIZATION OF SEDIMENT
- % dry weight of sphagnum moss peat: Not reported
- Particle size distribution
- % fine sand: 6 %
- % fine silt: 19 %
- % clay: 71 %

OTHER TEST CONDITIONS
- Light quality: Not reported
- Photoperiod: 16 h light: 8 h dark
- Light intensity: 400 ft-c at the water surface

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

Reference substance (positive control):
no
Key result
Duration:
72 h
Dose descriptor:
LC50
Effect conc.:
ca. 11.3 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
act. ingr.
Basis for effect:
mortality
Key result
Duration:
24 d
Dose descriptor:
LOEC
Effect conc.:
ca. 876 - ca. 2 708 mg/kg sediment dw
Nominal / measured:
meas. (not specified)
Conc. based on:
act. ingr.
Basis for effect:
emergence rate
Remarks on result:
other: equivalent to 842 - 2602 mg/kg sediment dw
Key result
Duration:
24 d
Dose descriptor:
NOEC
Effect conc.:
ca. 876 mg/kg sediment dw
Nominal / measured:
meas. (not specified)
Conc. based on:
act. ingr.
Basis for effect:
emergence rate
Remarks on result:
other: equivalent to 842 mg/kg sediment dw
Details on results:
- No significant reductions in egg hatching were observed at the highest concentration: 21.5 mg/L
- In the sorbed-sediment experiment with DSDMAC, a significant reduction in midge emergence was observed at the highest exposure
conditions tested: 2,708 µg/g in sediment, 0.18 mg/L in IW and 0.41 mg/L in OW
- NOECs of test material under these test conditions were equal to or greater than 876 µg/g in sediment (i.e., 876 mg/kg sediment dw).

Refer to the attachment for further details.
Results with reference substance (positive control):
Not applicable
Reported statistics and error estimates:
No data

None

Validity criteria fulfilled:
yes
Conclusions:
Under the study conditions, the 72-h LC50 and 24-d NOEC were determined to be 11.3 mg a.i./L based on survival of newly hatched larvae and 876 mg a.i./kg sediment dw, based on emergence, respectively
Executive summary:

A study was conducted to determine the toxicity potential of the test substance, C18 DAQ (96.1% active) on egg hatchability and partial life cycle of midge (Chironomus riparius), following method equivalent or similar to OECD Guideline 218. In the egg hatchability test, the midge eggs were exposed to a range of test substance concentrations in water under semi-static conditions and were monitored for hatching success and post-hatch survival. All results are based on the measured concentration of the test substance. No significant reduction in egg hatching was observed at the highest concentration tested (21.5 mg/L). The 72 h LC50 was determined to be 11.3 mg/L, based on survival of newly hatched larvae. In the partial life cycle chronic bioassay in a flow-through sediment/water test system, percentages of winged adults emerging after continuous exposure of larvae and pupae to a range of test substance concentrations were determined. Exposure concentrations in sediment, interstitial water (IW) and overlying water (OW) were monitored by 14C liquid scintillation counting. Significant reduction in the emergence rate was observed at tested conc. of 876 µg/g (dry weight). Hence, the NOEC of sediment-spiked test material was 876 mg a.i./kg sediment dw. Under the study conditions, the 72-h LC50 and 24-d NOEC were determined to be 11.3 mg a.i./L based on survival of newly hatched larvae and 876 mg a.i./kg sediment dw, based on emergence, respectively (Pittinger, 1989).

Endpoint:
sediment toxicity: long-term
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
Not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
Refer to section 13 of IUCLID for details on the read-across justification. The study with the read across substance is considered sufficient to fulfil the information requirements.
Reason / purpose for cross-reference:
read-across source
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 218 (Sediment-Water Chironomid Toxicity Test Using Spiked Sediment)
Deviations:
not specified
Principles of method if other than guideline:
Not applicable
GLP compliance:
no
Analytical monitoring:
yes
Details on sampling:
SEDIMENT
- Natural stream sediments used in developmental assays were collected from a pristine site in Rapid Creek, South Dakota, and contained no detectable levels of test materials, pesticides or heavy metals as determined by GC and atomic adsorption spectrophotometric analyses.
- The particle size distribution was determined to be: clay (71 %), fine silt (19 %) and medium (40 %) and fine sands (6 %). The organic carbon content of the test sediments was 4.2 % prior to testing.

Vehicle:
no
Details on sediment and application:
No data
Test organisms (species):
Chironomus riparius
Details on test organisms:
TEST ORGANISM
- Common name: Fresh water midge
- Source: Reared in 10-gallon tanks with screened tops, containing 4 gallons of aerated well water replenished at a rate of approximately 2 L/h.
- Age of animals at beginning of exposure: 10 to 14 d posthatch
- Breeding conditions: Midges used in this study were reared in 10-gallon tanks, with screened tops, containing 4 gallons of aerated well water replenished at a rate of 2 L/hr. Two inches of natural stream sediment served as substrate in culture chambers. Midge cultures (and test organisms) were fed a mixed diet of Ralston-Purina trout chow-dehydrated alfalfa (5:1, w/w). This was supplemented with commercial dog treats at a rate adjusted to prevent fouling. Cultures were maintained at 22± 2 ° C. Water hardness was 150 mg/L as CaCO3, pH ranged 7.8 to 8.4, and there was a 16:8 h photoperiod (400 ft-c).
- Food type: Mixed diet of Ralston-Purina trout chow dehydrated alfalfa (5: 1, w/w). This was supplemented with commercial dog treats
- Age of animals at beginning of exposure: 1-2 d

ACCLIMATION
- Acclimation period: Not reported. However, midges were obtained in-house, cultured under the same conditions as the test.
- Acclimation conditions (same as test or not): Same
- Type and amount of food: See description of culture above.

Study type:
laboratory study
Test type:
other: Semistatic (Egg hatchability) & Flow through (Chronic assay)
Water media type:
freshwater
Type of sediment:
natural sediment
Limit test:
no
Duration:
24 d
Exposure phase:
total exposure duration
Remarks:
Chronic assay
Post exposure observation period:
Not reported
Hardness:
150 mg/L as CaCO3
Test temperature:
22±2 °C
pH:
7.8-8.4
Dissolved oxygen:
Not reported
Salinity:
Not reported
Ammonia:
Not reported
Nominal and measured concentrations:
The publication does not provide the nominal test concentrations. Instead, only the measured concentrations are available.
Egg hatchability: Measured concentration: 0.0, 2.6, 4.4, 7.8, 10.7, 14.4, 21.5 mg/L
Details on test conditions:
TEST SYSTEM
- Test container (material, size): 13 W x 25 L x 18 H cm dimensions chamber (chronic assay); 50 mL Cylindrical test chamber with Nitex® bottom ( Hatchability);
- Weight of wet sediment with and without pore water: 350 g sediment (dry weight equivalent) per test chamber; Wet sediment was autoclaved for 40 to 60 min before testing.


EXPOSURE REGIME (Egg hatchability)
- No. of organisms per container (treatment): 20 eggs in a loop
- No. of replicates per treatment group: Duplicate
- No. of replicates per control / vehicle control: Duplicate
- Feeding regime: Fed each day following water replenishment


EXPOSURE REGIME (Chronic assay)
- No. of organisms per container (treatment): 20 larvae per chamber
- No. of replicates per treatment group: Single
- No. of replicates per control / vehicle control: Single
- Feeding regime: Each food formulation daily
- Amount of food: 1 mL

RENEWAL OF OVERLYING WATER
- Details on volume additions:
Egg hatchability test: Replenished daily by trickling 150 mL directly into each test chamber and allowing excess volume from the overflow beaker to drain.
Chronic test: flow-through design; details on renewal not provided.


OVERLYING WATER CHARACTERISTCS:
- Type of water: Blend of deionized, reverse osmosis water and well water with a hardness of approximately 150 mg/L as CaCO3.This “blended” water, a mixture of deionized and well water, is often used in environmental testing at P&G. The details are not provided in the publication, but this water has been well characterized.


SOURCE OF NATURAL SEDIMENT
- Location and description of sampling site: Pristine site in Rapid Creek, South Dakota
- Contamination history of site: Contained no detectablelevels of test materials, pesticides or heavy metals

CHARACTERIZATION OF SEDIMENT
- % dry weight of sphagnum moss peat: Not reported
- Particle size distribution
- % fine sand: 6 %
- % fine silt: 19 %
- % clay: 71 %

OTHER TEST CONDITIONS
- Light quality: Not reported
- Photoperiod: 16 h light: 8 h dark
- Light intensity: 400 ft-c at the water surface

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

Reference substance (positive control):
no
Key result
Duration:
72 h
Dose descriptor:
LC50
Effect conc.:
ca. 11.3 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
act. ingr.
Basis for effect:
mortality
Key result
Duration:
24 d
Dose descriptor:
LOEC
Effect conc.:
ca. 876 - ca. 2 708 mg/kg sediment dw
Nominal / measured:
meas. (not specified)
Conc. based on:
act. ingr.
Basis for effect:
emergence rate
Remarks on result:
other: equivalent to 842 - 2602 mg/kg sediment dw
Key result
Duration:
24 d
Dose descriptor:
NOEC
Effect conc.:
ca. 876 mg/kg sediment dw
Nominal / measured:
meas. (not specified)
Conc. based on:
act. ingr.
Basis for effect:
emergence rate
Remarks on result:
other: equivalent to 842 mg/kg sediment dw
Details on results:
- No significant reductions in egg hatching were observed at the highest concentration: 21.5 mg/L
- In the sorbed-sediment experiment with DSDMAC, a significant reduction in midge emergence was observed at the highest exposure
conditions tested: 2,708 µg/g in sediment, 0.18 mg/L in IW and 0.41 mg/L in OW
- NOECs of test material under these test conditions were equal to or greater than 876 µg/g in sediment.

Refer to the attachment for further details.
Results with reference substance (positive control):
Not applicable
Reported statistics and error estimates:
No data

None

Validity criteria fulfilled:
yes
Conclusions:
Based on the results of the read across study, the 72-h LC50 and 24-d NOEC were determined to be 11.3 mg a.i./L based on survival of newly hatched larvae and 876mg a.i./kg sediment dw, based on emergence, respectively.
Executive summary:

A study was conducted to determine the toxicity potential of the read across substance, C18 DAQ (96.1% active) on egg hatchability and partial life cycle of midge (Chironomus riparius), following method equivalent or similar to OECD Guideline 218. In the egg hatchability test, the midge eggs were exposed to a range of read across substance concentrations in water under semi-static conditions and were monitored for hatching success and post-hatch survival. All results are based on the measured concentration of the read across substance. No significant reduction in egg hatching was observed at the highest concentration tested (21.5 mg/L). The 72 h LC50 was determined to be 11.3 mg/L, based on survival of newly hatched larvae. In the partial life cycle chronic bioassay in a flow-through sediment/water test system, percentages of winged adults emerging after continuous exposure of larvae and pupae to a range of read across substance concentrations were determined. Exposure concentrations in sediment, interstitial water (IW) and overlying water (OW) were monitored by 14C liquid scintillation counting. Significant reduction in the emergence rate was observed at tested conc. of 876 mg a.i./kg sediment dw. Hence, the NOEC of sediment-spiked test material was 876 mg a.i./kg sediment dw. Under the study conditions, the 72-h LC50 and 24-d NOEC were determined to be 11.3 mg a.i./L based on survival of newly hatched larvae and 876 mg a.i./kg sediment dw, based on emergence, respectively (Pittinger, 1989). Based on the results of the read across study, similar effect levels are expected for the test substance.

Endpoint:
sediment toxicity: short-term
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
March 20, 1998 to March 30, 1998
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Remarks:
Study conducted according to PARCOM 1995 (Corophiumsp sediment reworker) in compliance with GLP
Qualifier:
according to guideline
Guideline:
other: PARCOM 1995 (Corophiumsp sediment reworker)
Deviations:
no
Principles of method if other than guideline:
The method involves the separate spiking of a portion of clean base sediment with the test substance to achieve the desired nominal test concentrations, expressed on a dry sediment weight basis, followed by 22h of mixing to achieve an even distribution of the test substance through that sediment. The test animals are exposed to the spiked sediments in a static exposure under aeration, lasting 10 days.
GLP compliance:
yes
Analytical monitoring:
no
Details on sampling:
No sampling performed
Vehicle:
no
Details on sediment and application:
- The base substrate consisted of a mixture of two natural marine sediments collected from almost the same location as the test animals. These sediments were selected on the basis of the standard criteria listed in the guideline.
- The sediments were sieved at 0.5 mm after arrival to remove predators, broken shell and larger particles. The physical characteristics of the surface sediments at these locations were analysed according to a standard procedure used by the TNO laboratories at Den Helder. After that a mixture of these two sediments was made on dry weight basis.
- The test substance was dosed as dispersions in natural seawater. For each test substance concentration in the final test, ca. 400 g of dry spiked sediment was required.
- To achieve test concentrations of 100, 320, 1000, 3200 and 10000 mg of the test substance test material per kg dry natural sediment, quantities of 40.7, 128.3, 402.6, 1280.1 and 4001.5 mg were accurately weighed out and each amount was dissolved in 100 mL of natural seawater.
- These dispersed stock solutions of 100 mL were then transferred to glass mixing jars containing about 570.9 g of damp natural sediment (400 g of dry sediment). In order to ensure thorough mixing, 129.1 mL of natural seawater was extra added.
- Glass jars were sealed and rolled for about 22 h on a roller bank at about 15 °C. Natural sediment treated in the same way as the spiked sediments was used as a control without the spiking step.
Test organisms (species):
Corophium sp.
Details on test organisms:
TEST ORGANISM
- Common name: Burrowing amphipod crustacean Corophium sp.
- Source: Southern shore of the Eastern Scheldt, The Netherlands
- Details on collection: Located near to the intake point where sea water is mixed with a little freshwater
- Size: Test animals were between 5-8 mm (excluding anttennae)
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:
No post exposure observation period.
Hardness:
Not reported
Test temperature:
15.0- 15.3 ºC
pH:
7.6- 8.0
Dissolved oxygen:
6.8 mg/L
Salinity:
32.0 - 33.1 % (parts per thousand)

Ammonia:
Not reported
Nominal and measured concentrations:
Nominal: 0, 100, 200, 320, 10000 mg/L

Details on test conditions:
TEST SYSTEM
- Test container (material, size): Glass beakers with a volume of about 250 mL.
- Aeration: yes

EXPOSURE REGIME
Five test animals per replicate and four replicates per concentration were used in a static aerated exposure lasting 10 d.

OVERLYING WATER CHARACTERISTCS
Salinity is normally ca. 32 % (parts per thousand). The water was filtered and checked for volatile organics, organochlorine compounds and oil.


SOURCE OF NATURAL SEDIMENT
The sediment was collected on the southern shore of the Eastern Scheldt, The Netherlands. This location is close to a break in the former sea dike where a trickle of freshwater emerges. Very little pollution found here.

CHARACTERIZATION OF SEDIMENT
The base sediment used in the test is a mixture of tow sediments and has a measured median grain-size of between 63 and 125 µm (88.8 %), a silt clay (< 63µm) fraction of 5.1 % and an organic matter content of 0.65=6 % (weight loss on ignition).


OTHER TEST CONDITIONS
- Photoperiod: 16 h light- 8 h dark regime with transition periods of 30 min


TEST CONCENTRATIONS
100, 320, 1000, 3200 and 10000 mg of test substance
Reference substance (positive control):
no
Key result
Duration:
10 d
Dose descriptor:
LC50
Effect conc.:
ca. 637.5 mg/kg sediment dw
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
mortality
Key result
Duration:
10 d
Dose descriptor:
LC50
Effect conc.:
ca. 850 mg/kg sediment dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Key result
Duration:
10 d
Dose descriptor:
NOEC
Effect conc.:
ca. 320 mg/kg sediment dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: equivalent to 240 mg a.i./kg sediment dw
Key result
Duration:
10 d
Dose descriptor:
NOEC
Effect conc.:
ca. 320 mg/kg sediment dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
behaviour
Remarks on result:
other: equivalent to 240 mg a.i./kg sediment dw
Details on results:
- During the 10 d test, no mortality was observed in the control population
Results with reference substance (positive control):
Not reported
Reported statistics and error estimates:
- The effect of a test substance on the mortality of animals is expressed by a quantity denoted as LC50 The LC50 is qualified according to duration of
exposure. The LC50 value and its confidence interval were calculated by means of a parametric model developed by Kooijman.

Table 1. Number of surviving animals, exposed to sediments spiked with test material

Time (days)

Nominal concentration (mg.kg-1dry sediment weight)

0

100

320

1000

3200

10000

0

20

20

20

20

20

20

10

20

19

20

8

0

0

 

Table 2. Results of the test with Corophium sp., exposed to sediments spiked with test material

Parameter

Effect

Nominal concentrations mg.kg-1dry sediment weight)

10d LC50

mortality

850

10d NOEC

mortality

320

10d NOEC

Behaviour/condition

320

 

Validity criteria fulfilled:
yes
Remarks:
With restrictions
Conclusions:
Under the study conditions, the 10 d LC50 and NOEC (mortality and behavioural) of the test substance were determined to be 850 and 320 mg/kg, sediment dw (equivalent to 637.5 and 240 mg a.i./kg sediment dw), respectively.
Executive summary:

A study was conducted to determine the sediment toxicity of test substance, C12-18 DAQ (75% active) to Corophium sp. according to PARCOM 1995 (Corophium sp. sediment reworker), in compliance with GLP. Five test animals per replicate and four replicates per concentration were used in a static aerated exposure lasting 10 days. The test substance concentrations used were 100, 320, 1000, 3200 and 10,000 mg/kg of test material (dry sediment basis). The test medium (natural sediment + test substance) was separately prepared for each test concentration by adding the appropriate weight of test substance to ca. 400 g (dry weight) of natural sediment and mixing these for 22 h on a roller bank. The test results were expressed as nominal concentrations. Following 10 d of exposure in the test system, there was no mortality among the control population. Under the study conditions, the 10 day LC50 and NOEC (mortality and behavioural) of the test substance were determined to be 850 and 320 mg/kg, sediment dw (equivalent to 637.5 and 240 mg a.i./kg sediment dw), respectively (Henzen, 1998).

Endpoint:
sediment toxicity: short-term
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
From October 02, 1993 to October 15, 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Remarks:
Study conducted according to PARCOM ring test protocol for Abra test May 1993 in compliance with GLP
Qualifier:
according to guideline
Guideline:
other: PARCOM ring test protocol for Abra test May 1993
Deviations:
not specified
Principles of method if other than guideline:
Not applicable
GLP compliance:
no
Analytical monitoring:
no
Details on sampling:
Not sampled in the study
Vehicle:
no
Details on sediment and application:
PREPARATION OF SPIKED SEDIMENT
The test media was prepared by directly adding the test substance to natural seawater. Collected from a locality where the organism is present. It is sieved through a 45 µm mesh. Stored at between 6-8 °C
Test organisms (species):
other: Abra alba (subtidal bivalve)
Details on test organisms:
TEST ORGANISM
- Common name: Abra alba
- Justification for species other than prescribed by test guideline: This system has been selected as a sediment reworker sensitive to toxic substances in the marine environment.
- Size: > 5mm (largest diameter)
-Feeding: Organic material in the seidment. Homogenised faeces of Mytilus was added to obtain a minimum fecal production rate.

Holding conditions:
- In natural sediment under continuous flow of natural seawater at ambient temperature and salinity of >20%.
Sediment; collected from a locality where also A. Alba is present and sieved through a 45μm mesh. Storage at 6 - 8 °C. Quality of the sediment is judged from the fecal pellet production rate.
- Medium: Standard sediment suspension with 8 % sediment particle content (dry-weight) and particle size <45μm. Storage at 11 °C under continuous aeration.

ACCLIMATION
- Acclimation period: at least 5 d before the start of the preexposure period. A surplus of +25% is acclimated.
Study type:
laboratory study
Test type:
static
Water media type:
saltwater
Type of sediment:
natural sediment
Limit test:
no
Duration:
120 h
Exposure phase:
total exposure duration
Post exposure observation period:
No data
Hardness:
No data
Test temperature:
11°C
pH:
No data
Dissolved oxygen:
No data
Salinity:
32-34%
Ammonia:
No data
Nominal and measured concentrations:
Nominal: 102, 1708, 3772, 10200 and 50000 mg/kg measured as weight test substance/weight total test medium
Details on test conditions:
TEST SYSTEM
- Test container (material, size): Polyethylene tubes with inner diameter of 36 mm, outer diameter of 40 mm and mesh size of 90 µm. Series of 15 tubes are glued together in a rack of 3*5 sieves, corresponding to about 12*20 cm.
- Depth of sediment and overlying water: Depth of settled sediment 1 mm
- Test duration: pre-exposure: 2 d; exposure 5 d
- Test parameter: fecal pellet production of A. Alba
- Controls: test medium without test substance or other additives
- Number of test organisms: 25-30 A. Alba per concentration and in the control
- Loading: One test organism per tube i.e. 15 individuals per container in 250 mg of 8% standard sediment suspension.
- Depth of settled sediment is about 1 mm
- Introduction of A alba: directly after preparation of the test media.
- Fecal production: the average fecal pellet production during 2 days pre-exposure should be ≥ 2mg/ind/day before exposure is started.

EXPOSURE REGIME
25-30 A. alba per concentration and in the controls. One test organism per tube i.e. 15 individuals per container in 250 mg of 8 % standard sediment suspension.

SOURCE OF NATURAL SEDIMENT
Collected from a locality where the organism is present. It is sieved through a 45 µm mesh. Stored at between 6-8 °C
Reference substance (positive control):
yes
Remarks:
2.4 mg/L 3,5-dichlorophenol (97%)
Key result
Duration:
120 h
Dose descriptor:
EC50
Effect conc.:
ca. 45 146 mg/kg sediment dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: fecal pellet production
Remarks on result:
other: ±4055
Remarks:
equivalent to 33860 mg a.i./kg sediment dw
Details on results:
EC50 = 45146 mg/kg (PPM) with estimated standard error (SE) = ± 4055 (corresponding to a 95 % confidence interval of about ± 8110).
Results with reference substance (positive control):
Accepted range for the reference substance is a fecal pellet production rate of 25 - 45 % of control after 96-120 h of exposure. The reference substance had a 32 % inhibition value
Reported statistics and error estimates:
Not reported

EC50 value: the test concentration giving 50% reduction in fecal pellet production after 96 - 120 h of exposure = 45146 mg/kg ± 4055 mg/kg of total medium.

Conclusions:
Under the study conditions, the EC50 of the test substance was determined to be 45146 mg/kg (PPM) (equivalent to 33860 mg a.i./kg sediment dw) with estimated standard error (SE) = ± 4055 (corresponding to a 95 % confidence interval of about ± 8110).
Executive summary:

A study was conducted to determine the acute toxicity potential of the test substance, C12-18 DAQ (75% active in hydroalcoholic solution) to Abra alba (mollusc), according to test protocol approved by SFT and PARCOM. Abra alba were exposed to test substance in sediment mixed with natural seawater followed by the measurement of the fecal pellet production over 5 days. The test concentrations used in the study were 102, 1708, 3772, 10200 and 50000 mg/kg measured as weight test substance/weight total test medium. The test substance was a suspension in water. After settling for 2 d the water phase was siphoned off and the settled phase was added by weight to batches of 500 g standard sediment suspension to give the planned test concentrations. The control series were normal. The sensitivity control series showed 32% of control series which is within the acceptable range. Under the study conditions, the EC50 of the test substance was determined to be 45146 mg/kg (PPM) (equivalent to 33860 mg a.i./kg sediment dw) with estimated standard error (SE) = ± 4055 (corresponding to a 95 % CL of about ± 8110) (Stromgren, 1993).

Description of key information

Based on a long-term sediment toxicity studies available with the read across substance C18 DAQ in different freshwater sediment species, the NOEC values ranged from 876 to 5000 mg/kg sediment dw, while an EC10 was derived at 550 mg/kg sediment dw in a 28-day study with Tubifex tubifex.

Based on the short-term sediment toxicity studies available with the test substance in crustacean Corophium sp., a 10 d ay  LC50 of 850 mg/kg dw (equivalent to 637.5 mg a.i./kg sediment dw) and a NOEC 320 mg/kg sediment dw (equivalent to 240 mg a.i./kg sediment dw), were determined based on mortality and behaviour.

Key value for chemical safety assessment

EC50 or LC50 for freshwater sediment:
10.9 mg/kg sediment dw
EC50 or LC50 for marine water sediment:
637.5 mg/kg sediment dw
EC10, LC10 or NOEC for freshwater sediment:
550 mg/kg sediment dw

Additional information

Short-term/screening studies:

Saltwater:

Study 1:A study was conducted to determine the sediment toxicity of test substance, C12-18 DAQ (75% active) to Corophium sp. according to PARCOM 1995 (Corophium sp. sediment reworker), in compliance with GLP. Five test animals per replicate and four replicates per concentration were used in a static aerated exposure lasting 10 days. The test substance concentrations used were 100, 320, 1000, 3200 and 10,000 mg/kg of test material (dry sediment basis). The test medium (natural sediment + test substance) was separately prepared for each test concentration by adding the appropriate weight of test substance to ca. 400 g (dry weight) of natural sediment and mixing these for 22 h on a roller bank. The test results were expressed as nominal concentrations. Following 10 d of exposure in the test system, there was no mortality among the control population. Under the study conditions, the 10 day LC50 and NOEC (mortality and behavioural) of the test substance were determined to be 850 and 320 mg/kg, sediment dw (equivalent to 637.5 and 240 mg a.i./kg sediment dw), respectively (Henzen, 1998).

Study 2:A study was conducted to determine the acute toxicity potential of the test substance, C12-18 DAQ (75% active in hydroalcoholic solution) to Abra alba (mollusc), according to test protocol approved by SFT and PARCOM. Abra alba were exposed to test substance in sediment mixed with natural seawater followed by the measurement of the fecal pellet production over 5 days. The test concentrations used in the study were 102, 1708, 3772, 10200 and 50000 mg/kg measured as weight test substance/weight total test medium. The test substance was a suspension in water. After settling for 2 d the water phase was siphoned off and the settled phase was added by weight to batches of 500 g standard sediment suspension to give the planned test concentrations. The control series were normal. The sensitivity control series showed 32% of control series which is within the acceptable range. Under the study conditions, the EC50 of the test substance was determined to be 45146 mg/kg (PPM) (equivalent to 33860 mg a.i./kg sediment dw) with estimated standard error (SE) = ± 4055 (corresponding to a 95 % CL of about ± 8110) (Stromgren, 1993).

Besides these studies, the EU RAR on DODMAC (or C18 DAQ) (EU, 2002) lists a number of short-term study summaries on the long chain DAQs, which are described below:

Freshwater

C16-18 DAQ (77% active, 1.7% C16-18 and C18-unsatd. TMAC) was applied in a partial life cycle test with Chironomus riparius in natural lake water (Roghair et al. 1992). The water of the Lake Veluwe (Netherlands) contained 1-4 mg/L suspended solids and 7.1 - 9.3 mg/L DOC (pH = 8.5, 320 mg/L CaCO3). Eggs not older than 24 h were exposed in a static renewal system for 28 days. In one experiment larval weight, mortality, behaviour and appearance were affected with similar sensitivity and the NOEC for all was 0.8 mg/L (nominal concentration of active ingredient). In a second experiment the most sensitive endpoint was retardation in development with a NOEC of 1.4 mg/L. Besides a 96 h LC50 of 7.1 mg/L was given by the authors for the second instar larvae.

The effects of natural sediment and river water containing C16-18 DAQ on Paratanytarsus parthenogenica were assessed in a static test system over 20 days (Lewis & Wee 1983). Samples collected from different points along the Rapid Creek, South Dakota, contained 2 to 67 mg/kg C16-19 DAQ in the sediment and 0.008 to 0.092 mg/L in the water. Midge eggs exposed to these concentrations showed no significant difference in larval survival and adult emergence relative to the control with laboratory water.

Roghair et al. (1992) determined the acute effect of the technical product (77 % C16-18 DAQ, 1.7 % C16-18 and C18-unsatd. TMAC) on the pond snail Lymnea stagnalis in pond water without sediment. A 96 h-LC50 of 18 mg/L and a 96h-EC50 of 7.5 mg/L (reduced movements and withdrawal into the shell) was found. In 2 additional tests over a period of several weeks (29 resp. 26 days) the authors studied the effect of the test substance on snail mortality and reproduction. At the lowest nonlethal concentration of 1 mg/l the following sublethal effects were observed: retracted and curled antennae, depressed locomotory activity, withdrawal into the shell and decreased food intake. A NOEC of 320 μg/L was obtained.

Chronic studies

No chronic sediment toxicity could be located on C12 -18 DAQ. Therefore, read across studies available with structurally similar substance C18 DAQ are presented. Both the test and read across substances are di-alkyl dimethyl ammonium chloride compounds. C18 DAQ is structurally the same but only differs in containing longer average alkyl chain length. Slightly longer alkyl chains is possibly somewhat less bioavailable (due to relatively high sorption) and but will have higher intrinsic toxicity (due to additional ingestion of sorbed test substance) and therefore would represent a worst case.

Freshwater

A study was conducted to determine the toxicity potential of the read across substance, C18 DAQ (96.1% active) on egg hatchability and partial life cycle of midge (Chironomus riparius), following method equivalent or similar to OECD Guideline 218. In the egg hatchability test, the midge eggs were exposed to a range of read across substance concentrations in water under semi-static conditions and were monitored for hatching success and post-hatch survival for 72 h. All results are based on the measured concentration of the read across substance. No significant reduction in egg hatching was observed at the highest concentration tested (21.5 mg/L). In the partial life cycle chronic bioassay, the 72 h LC50 was determined to be 11.3 mg/L, based on survival of newly hatched larvae. In the partial life cycle chronic bioassay in a flow-through sediment/water test system, percentages of winged adults emerging after continuous exposure of the 72 h old larvae and pupae to a range of read across substance concentrations for 24 days were determined. Exposure concentrations in sediment, interstitial water (IW) and overlying water (OW) were monitored by 14C liquid scintillation counting. The concentration in the overlaying water was 0.29 mg/L and in the interstitial water 0.06 mg/L. Significant reduction in the emergence rate was observed at tested conc. of 876 mg/kg sediment dw. Hence, the NOEC of sediment-spiked test material was 876 mg a.i./kg sediment dw. Under the study conditions, the 72-h LC50 and 24-d NOEC were determined to be 11.3 mg a.i./L based on survival of newly hatched larvae and 876 mg a.i./kg sediment dw, based on emergence, respectively (Pittinger, 1989). Based on the results of the read across study, similar effect levels are expected for the test substance.

Apart from the above study, the EU RAR (EU, 2002) lists a number of other long-term study summaries on C18 DAQ, which are described below:

The toxicity of C18 DAQ to the oligochaete Lumbriculus variegatus was examined in a 28 day test using natural sediment (organic carbon content: 1.73 %). Ten intact worms per vessel were exposed to nominal C18 DAQ sediment concentrations between 150 and 5,800 mg/kg dw. for 28 days. A mixture of radio-labelled and non-labelled C18 DAQ was used for the experiment and the analytical determinations were made using the radio-labelled C18 DAQ. The endpoints of this test were survival, reproduction and growth. Survival and reproduction were treated as single endpoint, that is, the total number of worms per vessel at the end of the test. At the highest tested concentration no significant decline in worm number or biomass compared to the control was found. Observations throughout the test period showed that the worms did not even avoid the sediment at this concentration. Analytical monitoring showed that the concentration of C18 DAQ in the sediment did not decline significantly. For the highest tested concentration an average value of 4,830 ± 550 mg/kg was measured after 28 days. Therefore, from this test a NOEC of about 5,000 mg/kg dw can be derived (Conrad et al. 1999).

The toxicity of C18 DAQ to the oligochaete Tubifex tubifex was assessed using a 28 day sediment bioassay (Comber and Conrad, 2000). The same sediment as in the test with Lumbriculus was used. A mixture of radio-labelled and non-labelled C18 DAQ was used for the experiment and the analytical determinations were made using the radio-labelled C18 DAQ. 4 adult worms per test vessel (6 vessels per concentration) were exposed to the spiked sediment containing nominal C18 DAQ concentrations between 0 and 5,000 mg/kg dw. The examined endpoints were survival of the worms, number of juveniles and body weight. At the end of the test samples of overlying water and sediment were taken for analysis. The measured sediment concentrations ranged between 224 mg/kg dw and 3,600 mg/kg dw. All effect values were related to the measured concentrations. Up to the highest test concentration no effects on the survival of Tubifex were observed. Also in the dry weight of the adult worms no statistically significant difference was found between the control and the worms exposed to C18 DAQ. However, for the endpoint number of juveniles, a concentration effect was observed. A NOEC of 1,515 mg/kg dw and a LOEC of 2,484 mg/kg dw was found. Using a linear interpolation method, a mean EC50 of 3,022 mg/kg dw and an EC10 of 550 mg/kg dw was calculated.

A further sediment test with Caenorhabditis elegans, a bacterivorous nematode that is primary found in terrestrial soils but also in aquatic sediments, was recently performed with C16-18 DAQ (BSB (2000). An artificial sediment with an organic content of 2% was used. Test endpoints were growth, egg production and fertility. Before the start of the test, 0.25 mL of a bacterial suspension (E. coli in M9-medium) was added to each test vessel as food for the nematodes. Afterwards, 10 juvenile nematodes of the first stage were added to the vessels, containing 0.5 g sediment, 0.5 mL test solution and 0.25 mL bacterial suspension. The vessels were incubated for 72 h at 20 °C on a shaker. At the end of the test, the nematodes were heat killed and stained with “Rose Bengal”. After extracting the nematodes from the sediment, body length and number of eggs inside the body were determined. A NOEC of 1,350 mg/kg dw and a LOEC of 2,030 mg/kg dw related to nominal concentrations was found.

The EU RAR further states that: "Among the above cited tests with sediment organisms four tests are appropriate for the effects assessment of sediment: the studies by Pittinger et al., Conrad et al., Comber/Conrad and BSB. For Chironomus riparius a NOEC of 876 mg/kg dw was found. Lumbriculus variegatus was less sensitive to adsorbed C18 DAQ. A NOEC of about 5,000 mg/kg dw was found for this sediment ingesting worm. For the nematode Caenorhabditis elegans a NOEC of 1,350 mg/kg dw was derived. The NOEC found for the oligochaete Tubifex tubifex was with 1,515 mg/kg dw in the same range with the NOECs from the other tests. However, an EC10-value of 550 mg/kg dw could be calculated that is used a basic value for the PNEC derivation."

Therefore, in line with EU RAR and as a conservative approach, an EC10 of 550 mg/kg sediment dw derived based on a chronic study with read across substance C18 DAQ in Tubifex tubifex has been considered further for hazard/risk assessment.