Propargite

Sediment toxicity

Link to relevant study record(s)

Reference

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2nd February 2001 to 10th July 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 219 (Sediment-Water Chironomid Toxicity Test Using Spiked Water)

Version / remarks:

(draft guidelines)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

SEDIMENT
- Concentrations: all
- Sampling interval: 2 hours and 7 and 28 days after application

OVERLYING WATER
- Concentrations: replicates 1 and 2 from all concentrations
- Sampling interval: 2 hours and 3, 7, 14 and 28 days after application

VESSEL WASHINGS
- Concentrations: replicates 1 and 2 from all concentrations
- Sampling interval: 28 days after application

Vehicle:

yes

Details on sediment and application:

PREPARATION OF SPIKED WATER
- Details of spiking: applied just below the surface of the water column
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): ethanol

Test organisms (species):

Chironomus riparius

Details on test organisms:

TEST ORGANISM
- Source: in-house laboratory culture
- Breeding conditions/Handling of egg masses and larvae: egg masses were hatched under conditions similar to the test and larvae were transferred to vessels containing sediment and aqueous medium as used in the test. These were held in culture boxes containing space for emerged midges to swarm. Egg ropes produced were used for the test.
- Age of animals at beginning of exposure: freshly laid egg ropes were collected and transferred to fresh medium and hatched at test temperatures. The eggs began to hatch the next day and after a further 3 days (first instar), the larvae were transferred to the test vessels
- Feeding during test
- Food type: suspension of TetraMin® fish flake
- Amount: rate equivalent to 0.5 mg per larvae per day TetraMin®, increased to 1mg per day after the first 10 days
- Frequency: daily

Study type:

laboratory study

Test type:

static

Water media type:

freshwater

Type of sediment:

artificial sediment

Limit test:

no

Duration:

28 d

Exposure phase:

total exposure duration

Test temperature:

18-20.3 ºC

Dissolved oxygen:

50-98 % ASV

Nominal and measured concentrations:

0, 32, 100, 320, 1000 and 3200 µg/L

Details on test conditions:

TEST SYSTEM
- Test container (material, size): glass beakers of approximately 1 L capacity (double-housed in plastic 2 L capacity beakers for the radiolabelled test)
- Sediment depth: 2 cm
- Overlying water volume: 610 mL
- Depth of sediment and overlying water: 1:4
- Aeration: yes
- Replacement of evaporated test water, if any: as appropriate

EXPOSURE REGIME
- No. of organisms per container (treatment): 20
- No. of replicates per treatment group: 6
- No. of replicates per control / vehicle control: 6
- Type and preparation of food: suspension of TetraMin® fish flake
- Amount: rate equivalent to 0.5 mg per larvae per day TetraMin®, increased to 1mg per day after the first 10 days

OVERLYING WATER CHARACTERISTCS
- Type of water: Elendt M7 medium
- Conductivity: 0.63 mS

CHARACTERIZATION OF ARTIFICIAL SEDIMENT
- Composition: 10 % w/w sphagnum moss peat, 20 % w/w kaolin clay and 70% industrial sand
- Method of preparation: the three dry components were mixed with deionised water for 5 minutes
- Moisture: 79 %
- pH whole sediment: 6.0 ± 0.5

OTHER TEST CONDITIONS
- Photoperiod: 16 h light; 8 h dark

EFFECT PARAMETERS MEASURED:
- Emergence assessment: test vessels were checked daily and emerged insects knocked-down with CO2, removed, counted and sexed.

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0, 0.1, 1, 10 and 100 µg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

no

Key result

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

1 770 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

320 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

1 770 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: emergence ratio

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

1 000 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: emergence ratio

Key result

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

> 3 333 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

development rate

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

320 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

development rate

Details on results:

- No. of emerged male and female midges (per vessel and per day): > 80 % by day 28 in controls and treatment groups > 320 µg/L; 70 % emergence was recorded at 1000 µg/L; 3.75 % emergence was recorded at 3200 µg/L.
- Mean development rate of fully emerged midges: no treatment group showed a development ratio of < 50 % compared to the controls

Distribution of test material

Analysis of overlying water, sediment and interstitial water for radioactivity indicates that the applied test material was removed rapidly from the water phase and partitioned to the sediment phase. Losses from the overlying water increased with decreasing concentration with 16.8 to 27.3 % removal of radioactivity in the first 2 hours after dosing from the 1000 to 32 µg/L concentrations. The exception to this trend was the 33 % removal from the overlying water measured at 2 hours in the 3200 µg/L concentration. Losses from overlying water typically continued until day 7 by which time 79.3 to 88.9 % of applied radioactivity had been removed in the 32 to 3200 µg/L concentrations. By day 28, radioactivity levels in overlying water increased to 14.9 to 35.8 % of applied radioactivity. This may have been partly due to re-working of the sediment by test organisms but is also likely to have been due to degradation of the parent compound to more polar/soluble metabolites. Radioactivity in the interstitial water only constituted a minor fraction of the applied dose (<0.1, 0.16 to 0.27 and 0.55 to 2.0 % at 2 hours, day 7 and day 28, respectively). This indicates that the test material in the overlying water was adsorbed to the sediment phase although increased levels of radioactivity in the interstitial water by day 28 further supports the observation of the presence of radiolabeled degradation products. Radioactivity in the sediment phase rapidly increased after application of test material with 5.3 to 8.6 % of applied radioactivity in the sediment of the 32 to 1000 µg/L vessels at 2 hours and 17.1 % in the 3200 µg/L sediment at 2 hours. By day 28, mean sediment percentages of applied radioactivity were 36.7 to 61 %. This increase was generally proportional to concentration. Acetone washes of test vessels showed binding of propargite to be 2.4 to 7.1 % of applied levels.

Table 1: Total emergence and percent mean cumulative emergence

	Propargite concentration (µg equivalents/L)
Total emergence	Control	Solvent control	32	100	320	1000	3200
Day 15	6	0	3	5	0	0	0
% mean cumulative emergence	7.5	0	3.75	6.25	0	0	0
Day 16	23	26	38	35	16	0	0
% mean cumulative emergence	28.75	32.5	51.25	50	20	0	0
Day 17	52	51	63	56	40	6	0
% mean cumulative emergence	65	63.75	78.75	70	50	7.5	0
Day 18	71	68	72	60	62	10	0
% mean cumulative emergence	88.75	85	90	75	77.5	12.5	0
Day 19	75	71	75	65	69	27	0
% mean cumulative emergence	93.75	88.75	93.75	81.25	86.25	33.75	0
Day 20	75	71	77	67	73	41	0
% mean cumulative emergence	93.75	88.75	96.25	83.75	91.25	51.25	0
Day 21	75	71	77	67	73	48	0
% mean cumulative emergence	93.75	88.75	96.25	83.75	91.25	60	0
Day 22	75	72	77	67	73	52	0
% mean cumulative emergence	9375	90	96.25	83.75	91.25	65	0
Day 23	75	72	77	67	73	54	0
% mean cumulative emergence	93.75	90	96.25	83.75	91.25	67.5	0
Day 24	75	72	77	67	73	56	0
% mean cumulative emergence	93.75	90	96.25	83.75	91.5	70	0
Day 25	75	72	77	67	73	56	0
% mean cumulative emergence	93.75	90	96.25	83.75	91.5	70	0
Day 26	75	72	77	67	73	56	1
% mean cumulative emergence	93.75	90	96.25	83.75	91.5	70	1.25
Day 27	75	72	77	67	73	56	1
% mean cumulative emergence	93.75	90	96.25	83.75	91.5	70	1.25
Day 28	75	72	77	67	73	56	3
% mean cumulative emergence	93.75	90	96.25	83.75	91.5	70	3.75

Table 2: Emergence of male and female midges: total in four replicates

Number of emerged male and female midges

Conc (µg equivalent/L)

day 15

day 16

day 17

day 18

day 19

day 20

day 21

day 22

day 23

day 24

day 25

day 26

day 27

day 28

Total number of emerged midges

32

-/3M

9F/26M

20F/5M

9F/-

3F/-

2F/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

43F/34M

100

1F/4M

11F/19M

13F/8M

4F/-

5F/-

2F/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

36F/31M

320

-/-

2F/14M

6F/18M

18F/4M

7F/-

4F/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

37F/36M

1000

-/-

-/-

-/6M

-/4M

10F/7M

10F/4M

5F/2M

4F/-

2F/-

2F/-

-/-

-/-

-/-

-/-

33F/23M

3200

-/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

-/1M

-/-

-/2M

-/3M

Solvent control

-/-

5F/21M

17F/8M

16F/1M

3F/-

-/-

-/-

1F/-

-/-

-/-

-/-

-/-

-/-

-/-

42F/30M

Control

-/6M

-/17M

17F/12M

17F/2M

4F/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

-/-

38F/37M

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the test, the 28 day EC50 for emergence (survival) was 1700 µg/L as initially applied 14C-propargite equivalents; the corresponding NOEC was 320 µg/L as 14C-propargite equivalents. The same NOEC applies for rate of emergence (larval development rate) with an EC50 of > 3200 µg/L 14C-propargite equivalents. Analysis of overlying water, sediment and interstitial water for radioactivity indicates that the applied propargite was rapidly removed from water phase and partitioned to the sediment phase.

Executive summary:

The study was designed to determine the EC50 and NOEC of [14C]-propargite to the sediment dwelling life stage of Chironomus riparius. The study was performed in line with the draft version of the standardised guideline OECD 219.

Following a preliminary range finding study with non-labelled material, test concentrations for the definitive test were selected as 32, 100, 320, 1000 and 3200 µg/L. The test was conducted under static conditions with propargite added to the water column of a sediment water system containing first instar larvae of Chironomous. Radiolabelled test material was used so that the partitioning behaviour of the test material in the two-phase test system (sediment: water) could be observed over the duration of the study.

Chironomid midges emerged from test vessels from day 15 after application to the end of the test. Emergence in the two control treatments and the 32 to 320 µg/L groups was over 80 % and a majority of the midges had emerged by day 20 in these groups. Emergence in the 1000 µg/L group was 70 % by the end of the test. In the 3200 µg/L group, only 3 midges were observed and these did not begin to emerge until 26 days after application.

The EC50 for mortality of developing larvae and the emergence ratio (male to female) was 1770 µg equivalents/L. Effects on development rate did not span 50 % for the treatment levels tested. The statistically derived NOEC for larvae mortality and the midge development rate was 320 µg equivalents/L whereas it was 1000 µg equivalents/L for the emergence ratio. As only total radioactivity was monitored, the results of the study are reported as µg equivalents of the test material.

The majority of the [14C]-propargite was found in the overlying water or the sediment fraction by the end of the study. The largest fraction (36.7 to 61 % of the [14C]-propargite applied) was associated with the sediment. However, minimal concentrations detected in the overlying water were recorded at days 7 and 14. The radioactivity associated with [14C]-propargite appeared to be redistributing back to the overlying water by the end of the test. Compared to the minimum values, detected means of 4 to 15 % of the applied [14C]-propargite had returned to the overlying water by the end of the test. Total percent recovery of the radiolabeled material from all fractions ranged from 72.3 to 85.8 % of the applied [14C]-propargite. At the end of the test, 0.55 to 2 % of the radioactivity applied was associated with interstitial water. Acetone washings of the exposure vessels accounted for 2.4 to 7.1 % of the applied radioactivity.

Description of key information

Emergence (survival) EC50 1700 µg/L 14C-propargite equivalents, NOEC 320 µg/L 14C-propargite equivalents; study conducted in accordance with OECD Guideline 219 (draft version); Kelly and Allan, 2002

Additional information

Following a preliminary range finding study with non-labelled material, test concentrations for the definitive test were selected as 32, 100, 320, 1000 and 3200 µg/L. The test was conducted under static conditions with propargite added to the water column of a sediment water system containing first instar larvae of Chironomous. Radiolabelled test material was used so that the partitioning behaviour of the test material in the two-phase test system (sediment: water) could be observed over the duration of the study.

Chironomid midges emerged from test vessels from day 15 after application to the end of the test. Emergence in the two control treatments and the 32 to 320 µg/L groups was over 80 % and a majority of the midges had emerged by day 20 in these groups. Emergence in the 1000 µg/L group was 70 % by the end of the test. In the 3200 µg/L group, only 3 midges were observed and these did not begin to emerge until 26 days after application.

The EC50 for mortality of developing larvae and the emergence ratio (male to female) was 1770 µg equivalents/L. Effects on development rate did not span 50 % for the treatment levels tested. The statistically derived NOEC for larvae mortality and the midge development rate was 320 µg equivalents/L whereas it was 1000 µg equivalents/L for the emergence ratio. As only total radioactivity was monitored, the results of the study are reported as µg equivalents of the test material.

The majority of the [14C]-propargite was found in the overlying water or the sediment fraction by the end of the study. The largest fraction (36.7 to 61 of the [14C]-propargite applied) was associated with the sediment. However, minimal concentrations detected in the overlying water were recorded at days 7 and 14. The radioactivity associated with [14C]-propargite appeared to be redistributing back to the overlying water by the end of the test. Compared to the minimum values, detected means of 4 to 15 % of the applied [14C]-propargite had returned to the overlying water by the end of the test. Total percent recovery of the radiolabeled material from all fractions ranged from 72.3 to 85.8 % of the applied [14C]-propargite. At the end of the test, 0.55 to 2 % of the radioactivity applied was associated with interstitial water. Acetone washings of the exposure vessels accounted for 2.4 to 7.1 % of the applied radioactivity.