5,7-dichloro-4-(4-fluorophenoxy)quinoline;quinoxyfen (ISO)

Sediment toxicity

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

sediment toxicity: short-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1735 (Whole Sediment Acute Toxicity of Invertebrates, freshwater)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

- Substance ID: TSN 100097
- Lot No: DECO-97-152-1
- Purity: 97.3%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

acetone

Test organisms (species):

Chironomus dilutus (previous name: Chironomus tentans)

Study type:

laboratory study

Test type:

not specified

Water media type:

freshwater

Type of sediment:

artificial sediment

Limit test:

no

Duration:

10 d

Exposure phase:

other: Third instar larvae

Hardness:

152 to 180 mg CaCO3/L

Test temperature:

22.4 to 23.5°C

pH:

7.9 to 8.3

Dissolved oxygen:

5.9 to 8.7 mg/L (72 to 104% saturation)

Ammonia:

0.000486 to 0.00204 mg/L (test initiation)
0.000042 to 0.000166 mg/L (termination)

Conductivity:

327 to 347 μS/cm

Nominal and measured concentrations:

Nominal sediment concentrations: 0 (control), 0 (vehicle control), 1.6, 3.1, 6.3, 13, 25, and 50 mg a.i./kg
Mean measured sediment concentrations: < MQL, < MQL, 1.45, 2.84, 5.99, 12.1, 22.7, and 45.6 mg a.i./kg

Key result

Duration:

10 d

Dose descriptor:

EC50

Effect conc.:

> 45.6 mg/kg sediment dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

other: survival

Remarks on result:

other: highest concentration tested

Key result

Duration:

10 d

Dose descriptor:

NOEC

Effect conc.:

45.6 mg/kg sediment dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

other: survival and growth

Remarks on result:

other: highest concentration tested

Duration:

10 d

Dose descriptor:

LOEC

Effect conc.:

> 45.6 mg/kg sediment dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

other: suvival and growth

Remarks on result:

other: highest concentration tested

Validity criteria fulfilled:

yes

Conclusions:

10 d EC50 (Chironomus dilutus larvae): >45.6 mg a.i./kg (survival)
10 d NOEC (Chironomus dilutus larvae): 45.6 mg a.i./kg (survival and growth)

Executive summary:

10-day acute toxicity test was performed with the freshwater midge, Chironomus dilutus, exposed to the test substance within sediment following U.S. EPA OPPTS guideline 850.1735. The toxicological endpoints of concern were survival and growth. A 10-day range finding test was performed at nominal concentrations of 0 (control), 0 (vehicle control; acetone), 0.010, 0.10, 1.0, and 10 mg a.i./kg of formulated sediment. A target number of five midge larvae were added to duplicate replicates per treatment at initiation of the range finding test. The chironomids in the test chambers were observed for mortality and sublethal effects at test termination. After 10 days of exposure, survival was 90, 80, 70, 100, 80, and 100% in the control, vehicle control, 0.010, 0.10, 1.0, and 10 mg a.i./kg treatments, respectively. All surviving chironomids in the control, vehicle control, and each test substance treatment displayed normal behavior throughout the test and were normal in appearance at termination.

An initial definitive toxicity test was performed at nominal sediment concentrations of 0 (control), 0 (vehicle control, acetone), 6.3, 13, 25, 50, and 100 mg a.i./kg. Results from this test were inconclusive and the data were not used. Therefore, a second definitive toxicity test was performed at nominal sediment concentrations of 0 (control), 0 (vehicle control, acetone), 1.6, 3.1, 6.3, 13, 25, and 50 mg a.i./kg. Mean measured sediment concentrations were 1.45, 2.84, 5.99, 12.1, 22.7, and 45.6 mg a.i./kg.

The temperatures recorded within the test chambers ranged from 22.4 to 23.5°C during the study. The dissolved oxygen concentrations in the overlying water during the study ranged from 5.9 to 8.7 mg/L (72 to 104% saturation). The pH of the overlying water ranged from 7.9 to 8.3 during the study.

After 10 days of exposure, survival was 91, 94, 90, 89, 90, 90, 84, and 86% in the 0 (control), 0 (vehicle control), 1.45, 2.84, 5.99, 12.1, 22.7, and 45.6 mg a.i./kg treatments, respectively. All surviving animals were normal in appearance and behavior. There was no statistically significant reduction (Dunnett’s test, p > 0.05) for survival in any of the test substance treatments as compared to the control. The 10 day NOEC and LOEC for survival were 45.6 and >45.6 mg a.i./kg, respectively. The LC50 value was unable to be determined because mortality did not exceed 50% in any treatment. Based on the mean measured sediment values, the 10-day LC50 value was >45.6 mg a.i./kg, the highest concentration tested.

The mean dry weights of the surviving midge larvae were 1.35 and 1.24 mg per individual in the control and vehicle control treatments, respectively. The mean ash-free dry weights of the surviving midge larvae were 0.95, 0.87, 1.02, 0.91, 0.94, 0.90, 0.94 and 0.92 mg per individual in the 0 (control), 0 (vehicle control), 1.45, 2.84, 5.99, 12.1, 22.7, and 45.6 mg a.i./kg treatments, respectively. There was no statistically significant reduction (Dunnett’s test, p > 0.05) for ash-free dry weight in any of the test substance treatments as compared to the control. The 10-day NOEC and LOEC for ash-free dry weights were 45.6 and >45.6 mg a.i./kg dry sediment, respectively.

Reference 2

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The purpose of this test was to assess the chronic effects of 14C-test substance on the midge, Chironomus riparius, in a static test system in a 27-day exposure over the sediment. Survival and emergence were evaluated on days 10 and 27.

GLP compliance:

yes

Specific details on test material used for the study:

14C-XDE-795 Technical
Reference ID: A925-161
Radiochemical Purity: 99+ %

14C-XDE-795 Technical
Reference ID: Ref: A1249-39A
Radiochemical Purity: 97.6%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

acetone

Test organisms (species):

Chironomus riparius

Study type:

laboratory study

Test type:

static

Water media type:

freshwater

Type of sediment:

natural sediment

Limit test:

no

Duration:

27 d

Exposure phase:

other: first instar larvae

Hardness:

50 to 64 mg CaCO3/L

Test temperature:

19 to 22°C

pH:

7.4 to 8.3

Dissolved oxygen:

3.5 to 8.5 mg/L

Conductivity:

170-220 µmhos/cm

Nominal and measured concentrations:

Nominal day 0 aqueous concentrations: Control, vehicle blank, 31.3, 62.4, 125, 250, and 499 µg/L
Measured day 0 aqueous concentrations: 30.1, 60.7, 128, 251, and 508 µg/L
Measured day 0 sediment concentrations: 127, 257, 548, 1090, 1990 µg/kg

Key result

Duration:

27 d

Dose descriptor:

NOEC

Effect conc.:

128 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

emergence rate

Key result

Duration:

27 d

Dose descriptor:

LOEC

Effect conc.:

251 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

emergence rate

Duration:

27 d

Dose descriptor:

other: MATC

Effect conc.:

179 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

emergence rate

Validity criteria fulfilled:

yes

Conclusions:

27 d NOEC (Chironomus ripairus larvae): 128 µg/L (emergence)
27 d LOEC (Chironomus ripairus larvae): 251 µg/L (emergence)

Executive summary:

The chronic toxicity of the 14C-test substance to the midge, Chironomus riparius, was assessed in a 27-day exposure over sediment. First-instar larvae were exposed to five aqueous concentrations of the test substance, along with a control and an acetone-dosed vehicle blank treatment.

Nominal aqueous concentrations were 31.3, 62.4, 125, 250, and 499 µg per liter of test water. Ten replicate groups of, in most cases, 25 midge larvae each were exposed to each of the test and control treatments in 2-L glass beakers containing approximately 200 mL (1.5 cm depth) of sediment and 1800 mL (15 cm depth) of test facility hard blended water. In addition to the ten biological replicates, two additional replicates of each treatment and control were prepared to provide analytical samples of water and sediment. The two analytical replicates were sampled on days 0, 10, and 27 for analysis of 14C-residues in water and sediment.

Test chambers were maintained in a temperature-controlled water-bath at 19 to 21°C. Water quality parameters of temperature, dissolved oxygen, and pH were measured in each test chamber twice weekly during the test. Aeration was started one day before addition of test organisms in all test chambers to provide adequate oxygen saturation. Water chemistry parameters were generally within acceptable limits throughout the test, with mean values of 20.4 ± 0.4°C (range 19.4-21.5°C) for temperature, 7.8 ± 0.2 for pH (range 7.4-8.3), and 7.4 ± 0.8 mg/L (range 3.5-8.5 g/L) for dissolved oxygen.

Concentrations of 14C-residues in the water column at day 0 were 30.1, 60.7, 128, 251, and 508 µg/L (96-102% of nominal), decreasing to 11-14% of day-0 nominal by day 10 and 5-7% by day 27. Preliminary testing indicated that, of the 86-89% decrease in 14C-activity in the water column during the exposure, ~50% occurred within the first 48 hours after dosing the test system with the remaining 35-40% decrease by day 10. Concentrations of 14C-residues in sediment at day 0 were 127, 257, 548, 1090, and 1990 µg/kg. Concentrations of 14C-activity in sediment increased by a factor of 1.3-2.6x by day 10 and remaining at relative equilibrium for the remainder of the testing period.

Survival and emergence were evaluated on days 10 and 27. Mean survival of Chironomus riparius in pooled controls after 10 days was 82 ± 16%. Mean survival for all treatment groups was ≥74% and in no treatment level was survival statistically different from pooled controls. Survival of pooled controls at day 27 was 82 ± 21 %. Mean survival for test substance treatments at day 27 ranged from 77 to 97%. There was no concentration response and no treatment was statistically different from pooled controls. Percentages for emergence and survival were the same for day 27.

Mean wet and dry weights for the pooled controls on day 10 were 8.1 mg per larva (range 7.3-9.2 mg) and 1.4 mg per larva (range 1.3-1.6 mg), respectively. Mean larval weights were statistically different from pooled controls only at the 508 µg/L (measured) treatment level. Average time to emergence was statistically greater (alpha=0.05) at the two highest treatment concentrations. No statistical differences were detected in percent survival or emergence responses between males and females that could be attributed to treatment. No LC50/EC50 value or concentration response slope could be determined in this study due to the absence of adverse survival effects. However, a no-observed-effect concentration (NOEC) of 128 µg/L and a lowest-observed-effect concentration (LOEC) of 251 µg/L was determined based on the most sensitive response parameter, delayed time to emergence. The maximum acceptable toxicant concentration (MATC), based on delayed time to emergence, was calculated to be 179 µg/L.

Description of key information

10-day NOEC (Chironomus dilutus larvae): 45.6 mg/kg (survival and growth); OPPTS 850.1735; Reliability = 1

27-day NOEC (Chironomus ripairus larvae): 128 µg/L (emergence); no guideline; Reliability = 2

Key value for chemical safety assessment

EC50 or LC50 for freshwater sediment:

45.6 mg/kg sediment dw