Benzyldimethyl(octadecyl)ammonium chloride

Sediment toxicity

Link to relevant study record(s)

Reference

Endpoint:

sediment toxicity: long-term

Type of information:

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

Adequacy of study:

key study

Study period:

From October 14, 1993 to November 11, 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

KL2 due to RA

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:

according to guideline

Guideline:

other: U.S. EPA FIFRA 72-4 (b)

Version / remarks:

ASTM Document E 1383-93 and U.S. EPA-600/3-75-009

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Six analytical (abiotic) replicates of each concentration were used for the analysis of 14C residue analysis of water column, interstitial water (by centrifugation) and sediment. Duplicate replicates (abiotic) were processed on Days 0, 14 and 28 for analysis of 14C residues in each of the three matrices.

Vehicle:

no

Details on sediment and application:

Sediment used for the range-finding and definitive tests was obtained from an aquaculture pond at the University of Mississippi Biological Field Station, University, Mississippi. The sediment contaminants analyses were performed for organochlorines, organophosphates, and metals.
Texture, pH, cation exchange capacity (CBC), biological oxygen demand (BOD), chemical oxygen demand (COD), oil and grease, total organic carbon (TOC), ammonia-N, and Kjeldahl-N were detennined on a subsample of the actual test sediment.
Sediment samples were sieved through 5- and 10-mesh Nalgene sieves before use to remove large pieces of debris and indigenous organisms which might interfere with the test. Sediment samples were stored in a walk-in refrigerator at approximately 4 °C from the time of receipt until they were used for testing.

Preparation of test concentrations:
Application of the test substance was made directly to the sediment. A volume of wet sediment equivalent to 250 g dry weight of sediment (approximately 300 mL) was weighed into each of the 72 tared 2-L glass test beakers. The total sediment weight was recorded for each beaker. For each treatment level, a 70-mL aliquot of the definitive dosing solution or clean dilution water for the controls was added to each replicate beaker of wet sediment and mixed thoroughly.
Twelve replicate beakers of each control and test concentration were prepared. After dosing was complete, blended water was added to the beakers to bring the total volume to approximately 1800 mL and the beakers were placed into a 20°C water bath. The beakers were randomized within the water bath and left overnight to allow the water column to settle and the temperature of the test beakers to equilibrate. After the overnight equilibration, light aeration was supplied to each beaker.

Test design:
Six replicate groups of 10 midge larvae each were exposed to each concentration in 2 L glass beakers containing approximately 300 mL of sediment and 1500 mL of the prepared hard blended water. In addition to the six biological replicates, six analytical (abiotic) replicates of each concentration were prepared for destructive sampling to provide analytical samples of water column, interstitial water (by centrifugation), and sediment. No test organisms were added to these replicates. Duplicate analytical replicates were processed on days 0, 14, and 28 for analysis of 14C residues in each of the three exposure matrices.

Test organisms (species):

Chironomus sp.

Details on test organisms:

Midge (Chironomus tentans) lots No. CT-21893 and CT-21893 obtained from an ABC in-house culture
Age of organisms at study initiation: 10 days (second instar)

The Chironomus tentans used in this test were obtained on the same day as egg masses from a laboratory in-house culture. Larvae were hatched and maintained in the laboratory hard blended water in 8-L glass aquaria. Food/substrate was supplied as a suspension of fish food (Salmon Starter from Zeigler Bros), algae (Chlorella and Spirulina, KAL), Magic Wonn Food (Carolina Biological Supply), and alfalfa pellets (Bourn Feeds) supplied daily until the day before the test. Food components were analyzed and found to be free of contaminants.

Study type:

laboratory study

Test type:

static

Water media type:

other: ABC hard blended water

Type of sediment:

natural sediment

Limit test:

no

Duration:

28 d

Exposure phase:

larvae from first generation (P)

Hardness:

Fnal hardness: 130 to 160 mg/l (CaCO3)

Test temperature:

19 to 21 °C

pH:

pH: 8.1

Dissolved oxygen:

Dissolved oxygen: from 2.6 to 8.6 mg/L

Conductivity:

Conductivity: 250 to 430 µMhos/cm

Nominal and measured concentrations:

Nominal concentrations: 0, 125, 250, 500, 1000 and 2000 mg/kg
Mean measured concentrations: 0 (untreated control), 120, 260, 520, 1200 and 2100 mg of 14C-test substance equivalents/kg sediment. All results were reported as measured concentrations of ADBAC corrected for purity and equivalent oven-dry weight of sediment solids, EDW, when appropriate.

Details on test conditions:

Test system: Chambers contained 300 mL of treated sediment and 1500 mL synthetic hard water.
Total of 60 larvae per treatment level: 10 larvae per 6 replicate test chambers/test concentration.
Observations: larvae were observed in triplicate on days 14 and 28. Larvae survival and growth were quantified on Days 14 and 28, and emergence success was evaluated on Day 28.

Dilution water: The water was prepared by blending laboratory well water with well water treated by reverse osmosis, for a final hardness of 130 to 160 mg/l (CaCO3). Alkalinity, hardness and conductivity all tended to increase with increased concentration of test chemical and ranged from 94 to 196 mg/l CaCO3, 68 to 160 mg/l CaCO3 and 250 to 430 µMhos/cm, respectively, for all groups. The respective water column temperature, dissolved oxygen, and pH ranges were 19 to 21 °C, 2.6 to 8.6 mg/l, and 6.7 to 8.2, respectively.

Water quality parameters of temperature, dissolved oxygen, and pH were measured in each test chamber twice weekly during the test. Aeration was initiated on day 0 in all test chambers to provide adequate oxygen saturation.

Reference substance (positive control):

no

Key result

Duration:

28 d

Dose descriptor:

LC50

Effect conc.:

479 mg/kg sediment dw

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CI

Remarks:

377-600

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

520 mg/kg sediment dw

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

1 200 mg/kg sediment dw

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

520 mg/kg sediment dw

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

emergence rate

Key result

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

1 200 mg/kg sediment dw

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

emergence rate

Details on results:

On Day 14, the 520 and 1200 mg/kg treatment levels had significantly lower larval weights (wet and dry) than controls. There was a general decrease in mean larval weight with increasing sediment concentration of the test substance, but the difference was not statistically significant for the 120 or 260 mg/kg treatments.

Reported statistics and error estimates:

Statistical analysis of the concentration vs. effect data was obtained using a computerized LC50 program. Statistical comparisons of survival and emergence were performed using PC SAS software. An outlier detection test was perforn1ed on survival data to detect unusual survival values. Levene's test was used to determine homogeneity of variance across treatments. Chi-square and Fisher's exact test were used to assess statistical differences in survival between control and test treatments.
Survival and emergence data were analyzed by an analysis of variance method (SAS General Linear Model).

Validity criteria fulfilled:

yes

Conclusions:

Based on the results of the read across study, the 28-day survival and emergence NOEC and LOEC values for the test substance C18 ADBAC is considered to be 520 and 1200 mg/kg sediment dw (measured) respectively.

Executive summary:

A study was conducted to determine the toxicity of the read across substance, C12-16 ADBAC to sediment dwelling organisms according to U.S. EPA FIFRA 72-4 (b). Chironomus tentans (second-instar larvae) were exposed to a natural sediment containing mean measured concentrations of 0 (untreated control), 120, 260, 520, 1200 and 2100 mg of 14C-radiolabelled read across substance/kg sediment in an aerated 28-day static test. Ten larvae were placed in each of six replicate test chambers/test concentration for a total of 60 larvae per treatment level. Six analytical (abiotic) replicates of each concentration were used for the analysis of 14C residue analysis of water column, interstitial water (by centrifugation) and sediment. Duplicate replicates (abiotic) were processed on Days 0, 14 and 28 for analysis of 14C residues in each of the three matrices. Larvae were observed in triplicate on days 14 and 28. Larvae survival and growth were quantified on days 14 and 28, and emergence success was evaluated on Day 28. An LC50 was calculated for Days 14 and 28, and a 14-day EC50 value was calculated based on decreased observed midge size and mortality. NOEC and LOEC values were calculated based on more sensitive parameters, 14-day larval weights and 28-day average time to emergence. All results were reported as measured concentrations of the read across substance corrected for purity and equivalent oven-dry weight of sediment solids, EDW, when appropriate. Under the study conditions, the 14-day and 28-day LC50 values were calculated to be 548 and 479 mg/kg sediment dw respectively. The 28-day survival and emergence NOEC and LOEC values were established at 520 and 1200 mg/kg sediment dw respectively (England, 1995). Based on the results of the read across study, similar the effect concentrations can also be considered for the test substance, C18 ADBAC, for toxicity to sediment organisms.

Description of key information

Based on the results of the read across study, the 28-day survival and emergence NOEC and LOEC values for the test substance C18 ADBAC is considered to be 520 and 1200 mg/kg sediment dw (measured) respectively.

Key value for chemical safety assessment

EC50 or LC50 for freshwater sediment:

479 mg/kg sediment dw

EC10, LC10 or NOEC for freshwater sediment:

520 mg/kg sediment dw

Additional information

A study was conducted to determine the toxicity of the read across substance, C12-16 ADBAC to sediment dwelling organisms according to U.S. EPA FIFRA 72-4 (b). Chironomus tentans (second-instar larvae) were exposed to a natural sediment containing mean measured concentrations of 0 (untreated control), 120, 260, 520, 1200 and 2100 mg of 14C-radiolabelled read across substance/kg sediment in an aerated 28-day static test. Ten larvae were placed in each of six replicate test chambers/test concentration for a total of 60 larvae per treatment level. Six analytical (abiotic) replicates of each concentration were used for the analysis of 14C residue analysis of water column, interstitial water (by centrifugation) and sediment. Duplicate replicates (abiotic) were processed on Days 0, 14 and 28 for analysis of 14C residues in each of the three matrices. Larvae were observed in triplicate on days 14 and 28. Larvae survival and growth were quantified on days 14 and 28, and emergence success was evaluated on Day 28. An LC50 was calculated for Days 14 and 28, and a 14-day EC50 value was calculated based on decreased observed midge size and mortality. NOEC and LOEC values were calculated based on more sensitive parameters, 14-day larval weights and 28-day average time to emergence. All results were reported as measured concentrations of the read across substance corrected for purity and equivalent oven-dry weight of sediment solids, EDW, when appropriate. Under the study conditions, the 14-day and 28-day LC50 values were calculated to be 548 and 479 mg/kg sediment dw respectively. The 28-day survival and emergence data gave NOEC and LOEC values of 520 and 1200 mg/kg sediment dw respectively (England, 1995). Based on the results of the read across study, similar the effect concentrations can also be considered for the test substance, C18 ADBAC, for toxicity to sediment organisms.