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

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: OECD guideline 202

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

TSN 100010
XDE-795 fungicide
DR-0325-7474
Purity: 98.7

Analytical monitoring:

yes

Details on sampling:

- Test solutions were sampled and analyzed on days 0, 7, 8, 11, 14, and 21. On all sampling days, except day 8, individual 4-mL samples were obtained from each of the 32 test vessels; a 4-mL aliquot was obtained from each replicate beaker and transferred to either a 4-dram vial containing 1 mL DMF (days 0, and 7) or a 5- mL glass centrifuge tube containing 1 mL DMF (days 11, 14, and 21) resulting in a final solvent concentration of 20/80 DMF/lab dilution water. The samples collected on days 11, 14, and 21 were centrifuged for approximately 5 min. at 4000 rpm to remove algae. Aliquots of all stabilized samples (non-centrifuged and centrifuged) were analyzed by HPLC/UV. On day 8, only samples from the "B" replicates of the 60.0 and 36.0 µg/L nominal dose levels were sampled; 4-mL aliquots were collected similar to that done for day 7 samples. On day 21, four additional samples were collected from the "B" replicate at the high dose level (60.0 µg/L nominal concentration) and from the "A" replicate at the low dose level (4.7 µg/L nominal concentration).
Samples were collected from the mixing chamber on days 0, 7, 8, 11, 14, and 21 to determine the test substance concentrations.
The dilutor feedstock was sampled on days 0, 7, 11, 14, and 21 to confirm the concentration of the feedstock which had been prepared at a nominal concentration of 600 µg/mL of DMF.

Vehicle:

yes

Remarks:

dimethyl formamide (DMF)

Details on test solutions:

Four replicate test vessels (600 mL borosilicate beakers containing 5 holding tubes with one organism per tube) were maintained at each of six nominal exposure concentrations (60.0, 36.0, 21.6, 13.0, 7.8, and 4.7 µg/L of laboratory dilution water) in addition to four vessels each of control laboratory dilution water and solvent-dosed (N,N-dimethyl formamide or DMF) control laboratory dilution water. Test vessels were replenished on a regular intermittent cycle with test solutions delivered from a flow-through proportional dilutor which was fortified using a primary feedstock prepared at a nominal concentration of 600 µg/mL DMF.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Waterflea
- Strain: Daphnia magna straus
- Source: Laboratory reared (in-house)
- Food type: Daphnids were fed an algal diet of Selenastrum capricornutum three times weekly

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Test temperature:

19.5 to 20.5 °C

pH:

7.1 to 7.8

Dissolved oxygen:

>88% saturation

Nominal and measured concentrations:

Nominal: 4.7, 7.8, 13.0, 21.6, 36.0, 60.0 µg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 5 holding tubes /600 mL borosilicate beaker
- Type: Temperature controlled water bath
- Type of flow-through: Intermittent-flow proportional diluter
- Test volume: 200mL/cycle
- Volume Changes/24h: at least 4
- No. of organisms per vessel: 1 each in 5 tubes
- No. of vessels per concentration (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dilution water was obtained from the upper Saginaw Bay of Lake Huron off Whitestone Point and was limed and flocculated with ferric chloride by the City of Midland to reduce its hardness. Prior to its use in the laboratory, the water was sand-filtered, pH-adjusted with CO2, carbon-filtered, and UV irradiated.
- Total organic carbon: 1520 µg/L

OTHER TEST CONDITIONS
- Photoperiod: 16-hr light/8-hr dark with a 30 min dusk/dawn transition period

TEST CONCENTRATIONS
- Test concentrations: Based on the results of the 48-hr static acute study, the calculated 24-hr EC50 was 133 µg/L and the 48-hr EC50 was 83 µg/L with 95% confidence intervals of 97 - 200 µg/L and 30.4 - 228 µg/L respectively. The calculated 24-hr and 48-hr LC50s during the 48-hr static acute study were 278 µg/L and 91 µg/L, respectively. The top exposure level selected for this study was targeted at about 0.5 of the 24-hr EC50 value. The study was conducted under flowthrough conditions due to the nature of the feeding required for the growth, reproduction and survival of the test species for a 21-day exposure period.

Key result

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

> 47.2 µg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

> 47.2 µg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

growth

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

27.8 µg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

27.8 µg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

growth

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

47.2 µg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

47.2 µg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

growth

Details on results:

The first appearance of eggs in the brood sac were observed in the controls by day 6 and the first broods in the controls were observed on day 8. During this study there were no mortalities observed either in the lab dilution water control or the 16.4 µg/L exposure groups; however, mortality was observed in the following exposure levels (with percent mortality): vehicle control (15%), 3.0 (20%), 5.2 (5%), 9.8 (25%), 27.8 (20%), and 47.2 µg/L (5%). There were no statistically significant exposure-related effects on survival, number of broods or mean days to first brood. However, there was a statistically significant decrease in the number of young per adult at 47.2 µg/L. The average cumulative number of young per female in the water control, vehicle control, 3.0, 5.2, 9.8, 16.4, 27.8 and 47.2 µg/L exposure levels were 67.5, 74.5,54.3, 65.7, 79.9, 65.8, 64.6, and 28.3, respectively. There were no ephippia produced by any of the organisms. There was a lack of statistically significant response when evaluating weight as an indicator of growth. However, when analyzing length as the growth parameter, a statistically significant difference was observed at 47.2 µg/L (2.52 mm) when compared to the lab dilution water controls (3.02 mm).
The inhibition of both reproductive capabilities and growth (i.e. repressed length) observed in the 47.2 µg/L dose level is a valid toxicological response and is the reported LOEC value. The reported NOEC value of 27.8 µg/L is also congruent with analytical results mentioned above. These conclusions are based on the following results: the lack of any overlapping concentrations during the study conduct, and the averaged analyzed concentrations for both of these exposure levels (47.2 and 27.8 µg/L) were greater than 77% of nominal. The final point validating these results is that the average dilution factor was never less than 54% of each dose level between analyzed time periods.

Discrepancies were observed between nominal and analytical concentrations of the test substance in aqueous solution during the 21- day daphnid life-cycle toxicity test. The mean measured recovery of the dilutor feedstock solution (100 µL/L-DMF) averaged 591 µg/mL, equivalent to 98.5% of nominal with an observed target range of 95.0% on day 11 of exposure to 101% on days 0 and 21. The mean % recovery of the exposure dose levels during the conduct of the study averaged 73% of nominal. The recovery values from the analytical sampling days ranged from 23% on day 7 to 119% on day 14 . There was no overlap of test concentrations between dose levels during the study (the average dilution factor during the study was 0.59). Any differences were attributed to mechanical difficulties of the delivery system (feedstock and test vessels) and the adsorption to algal cells (test vessels only) used during the initial phase of the test.

Validity criteria fulfilled:

yes

Conclusions:

21-day EC50s for both reproduction and growth were > 47.2 µg/L
21-day NOEC for both reproduction and growth were 27.8 µg/L
21-day LOEC for both reproduction and growth were 47.2 µg/L
21-day MATC for both reproduction and growth were 36.2 µg/L.

Executive summary:

A 21-day life-cycle toxicity test was conducted with the daphnid, Daphnia magna Straus according to OECD guideline 202. This life-cycle test was conducted under flow-through conditions at 20 ± 1°C with mean analyzed concentrations in the range from 3.0 to 47.2 µg/L. Each exposure concentration consisted of four replicates (5 organisms/ replicate) to evaluate the effects on survival, reproduction and growth. These data were used to determine the maximum acceptable toxicant concentration (MATC). The MATC is defined as the theoretical toxic threshold concentration that falls between the highest concentration showing no effect (NOEC) and the lowest concentration showing a toxic effect (LOEC) when compared to the controls. The EC50s for both reproduction and growth were > 47.2 µg/L. The NOEC for both reproduction and growth were 27.8 µg/L. The LOEC for both reproduction and growth were 47.2 µg/L and the MATC for both reproduction and growth were 36.2 µg/L.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

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 850.1350 (Mysid Chronic Toxicity Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Quinoxyfen
Lot: DECO-97-152-1
Purity: 97.3

Test organisms (species):

Americamysis bahia (previous name: Mysidopsis bahia)

Test type:

flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

28 d

Remarks on exposure duration:

28 Days for G1 mysids; 96 hours for G2 mysids

Test temperature:

24.3 – 26.0°C

pH:

7.9 - 8.0

Dissolved oxygen:

≥67% (4.9 mg/L) except 9.3 µg a.i./L which dropped briefly to 4.0 mg/L); no aeration added

Salinity:

19-20%

Nominal and measured concentrations:

Nominal: 0 (negative control and solvent control), 0.17, 0.47, 1.3, 3.4, 9.3, 25 µg/L
Measured: 0, 0.21, 0.47, 1.2, 3.1, 9.3, 21 µg/L

Key result

Duration:

28 d

Dose descriptor:

LC50

Effect conc.:

> 21 µg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

1.2 µg/L

Nominal / measured:

meas. (not specified)

Key result

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

3.1 µg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

other: reproduction, male growth, female growth

Key result

Duration:

28 d

Dose descriptor:

other: MATC

Effect conc.:

2.1 µg/L

Nominal / measured:

meas. (not specified)

Details on results:

After 96-hours of exposure, survival of G2 juvenile mysids in the negative control, solvent control and in the 0.21, 0.47, 1.2, 3.1 and 9.3 µg a.i./L treatment groups was 67.5, 92.5, 90.0, 82.5, 92.5, 78.9 and 82.5%, respectively.

Validity criteria fulfilled:

yes

Conclusions:

7-, 13, 21- and 28-day LC50 (mysid) >21 µg a.i./L, the highest concentration tested.
28-day NOEC (G1 mysid reproduction and growth) was 1.2 µg a.i./L.
28-day LOEC = 3.1 µg a.i./L
28-day MATC was calculated to be 2.1 µg a.i./L.

Executive summary:

First-generation (G1) saltwater mysids (Americamysis bahia) were exposed to quinoxyfen under flow-through conditions for 28 days, and were evaluated for survival, reproduction and growth according to OPPTS guideline 850.1350. Second-generation (G2) saltwater mysids were evaluated for survival for approximately 96 hours. Nominal test concentrations selected were 0.17, 0.47, 1.3, 3.4, 9.3 and 25 µg active ingredient (a.i.)/L. In the first generation, mean measured concentrations ranged from 0.21 to 21 µg/L. Second generation mysids were exposed to 0.21, 0.43, 1.2, 3.1, 9.0 and 21 µg/L.

 

Reproduction and growth in the G1 mysids were the most sensitive biological endpoints measured. There were statistically significant decreases in G1 mysid reproduction and growth in the 3.1, 9.3 and 21 µg a.i./L treatment groups. There was less than 50% mortality in any of the treatment groups tested through Day 28 of the study. Therefore the 7-, 13, 21- and 28-day LC50 values were estimated to be >21 µg a.i./L, the highest concentration tested. Consequently, the NOEC, based on G1 mysid reproduction and growth, was 1.2 µg a.i./L. The LOEC was 3.1 µg a.i./L and the MATC was calculated to be 2.1 µg a.i./L.

Description of key information

21-day NOEC (Daphnia magna): > 47.2 µg/L (highest dose tested); OECD 202; Reliability = 1

28-day NOEC (Americamysis bahia): 1.2 µg/L; EPA OPPTS 850.1350; Reliability = 1

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

47.2 µg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

1.2 µg/L

Additional information

The NOEC from the 21-d chronic aquatic invertebrate toxicity test in Daphnia magna is > 47.2 µg/L (the highest dose tested), based on reproduction and development parameters. Americamysis bahia were also tested, with NOEC values of 1.2 µg./L. The marine species was more sensitive and the chronic NOEC for aquatic invertebrates are less than 0.1 mg/L.