Propargite

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13th April 1989 to 4th May 1989

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 204 (Fish, Prolonged Toxicity Test: 14-day Study)

Deviations:

yes

Remarks:

The fish were not fed for 48 hours prior to test initiation and three quality assurance samples were prepared at each sampling interval instead of two; neither of these deviations affected the results of the study.

Principles of method if other than guideline:

The study was aconducted according to OECD 204 but gives LC50 values at appropriate acute toxicity timepoints.

GLP compliance:

yes

Analytical monitoring:

not specified

Details on sampling:

Water samples were removed from both replicate test solutions of each treatment level and the controls on days 0, 7, 14 and 21 by collection from the approximate midpoint of the aquarium with a volumetric pipette.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A 7.24 mg/L stock was prepared by diluting 1.638 g test material with acetone in a 200 mL volumetric flask. 0.0348 mL/cycle test material stock solution was added to the diluter's mixing chamber containing 2.52 L dilution water. The solution in the mixing chamber contained the highest nominal test concentration and was subsequently diluted to provide the desired exposure concentration range.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): acetone
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): A solvent control stock of 397 µL/mL was prepared by diluting 39.7 mL acetone with distilled water to volume in a 100 mL volumetric flask.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: rainbow trout
- Length at study initiation (length definition, mean, range and SD): 52 (46-58) mm
- Weight at study initiation (mean and range, SD): 1.3 (0.86-2.1) g

ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions:
Hardness: 30 - 35 mg/L CaCO3
Alkalinity: 22 - 30 mg/L CaCO3
Conductance: 110 - 120 umhos/cm
pH: 7.1 7.2
DO: 83 - 91 %
Temperature: 13 - 14 ºC
- Type and amount of food: commercial pelleted food ad libitum except during the 48 hours prior to testing
- Feeding frequency: daily
- Feeding during exposure period: no
- Health during acclimation (any mortality observed): 0.63 % mortality

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

28-32 mg/L CaCO3

Test temperature:

14 - 15 ºC

pH:

7.0 - 7.1

Dissolved oxygen:

7.0-10.6

Nominal and measured concentrations:

14, 21, 32, 52 and 100 µg/L (measured)

Details on test conditions:

TEST SYSTEM
- Test vessel: intermittent flow proportional diluter
- Material, size, headspace, fill volume: 39 x 20 x 25 cm glass aquarium; test water volume 15 litres
- Aeration: none
- Renewal rate of test solution (frequency/flow rate): 500 mL of solution to each replicate test aquarium providing approximately 6.3 volume replacements per aquarium per 24 hours.
- No. of organisms per vessel: 20
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 2
- Biomass loading rate: 0.14 g per litre of test solution per day

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: well water
- Pesticides: none detected
- Alkalinity: 24-26 mg/L CaCO3
- Conductivity: 100-130 umhos/cm

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light; 8 hours darkness
- Light intensity: 65 (22-100) footcandles

EFFECT PARAMETERS MEASURED: mortality observed at test initiation and at 24 hour intervals

TEST CONCENTRATIONS
- Range finding study: a preliminary exposure was conducted under flow-through conditions at nominal concentrations ranging from 0.30 - 0.054 a.i./L. Following 17 days of exposure, 100 % mortality was observed in all treatment levels except the lowest (0.054 mg a.i./L). Based on these preliminary resutls, nominal concentrations of 100, 65, 42, 27 and 18 µg a.i./L were chosen for the definitive test.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

43 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95 % C.I. 38-49 µg/L

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

< 14 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

other: sublethal effects

Details on results:

- Following 96 hours of exposure, 100 % mortality was observed at the highest test concentration (100 µg a.i./L). Mortalities in the remaining treatments were 85, 20 and 0 %, respectively (52, 32, 21 and 14 µg a.i./L). By test termination, 100 % mortality was also observed at the 52 and 32 µg a.i./L treatment levels while 20 % of the organisms exposed to the 21 µg a.i./L treatment level had died. No mortality was observed in the remaining test concentration of 14 µg a.i./L, however, sublethal effects (e.g. partial or complete loss of equilibrium, darkened pigmentation) were observed among surviving fish in this treatment level.
- Mortality of control: none

Sublethal observations / clinical signs:

Table 1: Mean cumulative mortality (%)

Day	Control	Solvent Control	14 µg/L	21 µg/L	32 µg/L	52 µg/L	100 µg/L
1	0	0	0	0	0	0	30
2	0	0	0	0	0	15	65
3	0	0	0	0	10	40	100
4	0	0	0	0	10	80	100

Validity criteria fulfilled:

not specified

Conclusions:

Under the conditions of the test, the 96 hour LC50 was 43 µg/L and the 96 hour NOEC was determined to be <14 µg/L based on observed sublethal effects (darkened pigmentation).

Executive summary:

The purpose of this study was to estimate the acute toxicity of the test material to rainbow trout under flow-through conditions during a 21 day exposure period. In duplicate test aquaria, twenty organisms were exposed to five concentrations of the test material (18, 27, 42, 65 and 100 µg/L), a dilution water and solvent controls. Concentrations of the test material were maintained in the exposure vessels by introducing approximately 6.3 aquarium volumes per day of newly prepared test solution via an intermittent-flow proportional diluter apparatus. Each replicate solution was sampled and analysed for test material concentration on days 0, 7, 14 and 21 of the exposure period. Based on the results of these analyses, the mean measured test concentrations were 14, 21, 32, 52 and 100 µg/L. Throughout the exposure period, no undissolved test material was observed in any of the exposure vessels.

Biological observations were recorded at test initiation and every 24 hours thereafter. At 96 hour exposure, 100 % mortality was observed in the highest test concentration. The 96 hour LC50 was estimated to be 43 µg/L (95 % C.I. 38-49 µg/L). The LC50 values at 24, 48 and 72 hours were estimated to be >100 µg/L, 84 µg/L (95 % C.I. 70-110 µg/L) and 53 µg/L (95 % C.I. 46-62 µg/L), respectively.

Description of key information

96 hour LC50 43 µg/L; study conducted in accordance with OECD Guideline 204 (96 hour value taken during the course of this 21 day study); Sousa, 1990

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

43 µg/L

Additional information

The acute toxicity of propargite to rainbow trout was determined after 96 hours during a 21 day chronic toxicity study. The acute toxicity of propargite to bluegill sunfish was determined in a standard acute toxicity study. Both studies were performed to standardised guidelines and GLP and were both assigned a reliability score of 1. However, the rainbow trout study had a more worst-case LC50 and so on this basis it was determined to be the key study.

In the key study, rainbow trout were exposed under flow-through conditions during a 21 day exposure period. In duplicate test aquaria, twenty organisms were exposed to five concentrations of the test material (18, 27, 42, 65 and 100 µg/L), a dilution water and solvent controls. Each replicate solution was sampled and analysed for test material concentration on days 0, 7, 14 and 21 of the exposure period. Based on the results of these analyses, the mean measured test concentrations were 14, 21, 32, 52 and 100 µg/L. Biological observations were recorded at test initiation and every 24 hours thereafter. At 96 hour exposure, 100 % mortality was observed in the highest test concentration. The 96 hour LC50 was estimated to be 43 µg/L (95 % C.I. 38-49 µg/L). The LC50 values at 24, 48 and 72 hours were estimated to be >100 µg/L, 84 (95 % C.I. 70-110 µg/L) and 53 µg/L (95 % C.I. 46-62 µg/L), respectively.

In the supporting study, bluegill sunfish were exposed over a 96 hour period under continuous-flow conditions. Propargite was added to the test system at nominal concentrations of 0, 0.0625, 0.125, 0.25, 0.5 and 1.0 ppm (respective mean measured concentrations are 0, 0.04, 0.06, 0.181, 0.241 and 0.399 ppm) with a solvent and non-solvent control also included. The 96 hour LC50 value was determined to be 0.081 ppm. The NOEC values from survival and observed effects were determined to be 0.06 and 0.04 ppm, respectively.