polymeric zinc propylenebis(dithiocarbamate);propineb (ISO)

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:

2005-01-11 to 2005-03-01

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Proposal for a new OECD Guideline 219: “Sediment-Water Chironomid Toxicity Test Using Spiked Water”

Version / remarks:

April 2003

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

The concentration of Propineb was analysed in the overlying water column and the pore water of the sediment. Three times during the study (1 hour, 7 days and 28 days after application) additional prepared test vessels of the highest, medium, and the lowest test concentration were removed from the study. The overlying water layers of these test containers were decanted carefully. Wet sediments of each beaker were filtered by vacuum (glass micro fibre filter, mesh size 1.0 µm), and the filtrates (= pore waters) were analysed. In addition, the application solution, the overlying water and pore water of the control were also analysed on day 0.

Vehicle:

no

Details on sediment and application:

Sediment preparation:
Artificial sediment was used in the test, prepared 8 days before the start of the exposure period. It consisted of 75 -76 % fine quartz sand (68.2 % of the sand had a particle size of 0.05 - 0.2 mm), 4.0 - 5.0 % dried, finely ground peat (sphagnum peat; pH 2 - 4), 20 % kaolin (kaolinite content of about 56 %, pH value ca 7) and around 1 % calcium carbonate (pure, Merck) to adjust the pH value to 7 ± 0.5.

Sediment layer:
The bottom of the test vessels were covered with a 1.5 cm
layer of wet sediment (according to about 140g).

Culture medium:
M7-medium, based on de-ionised water, was used as breeding water.

Test medium:
M7-medium, based on de-ionised water, was added as test water to the sediment layer. To avoid a separation of the sediment ingredients during this procedure, the sediment was covered by a sheet, and the test water poured slowly into the vessels (final test water volume: 0.38 L). The sheet was removed carefully thereafter. The height of the water column was 6.0 cm.

Test item application:
The test item was applied to the water on day 0.

Test organisms (species):

Chironomus riparius

Details on test organisms:

TEST ORGANISM
-Feeding:
During the study the larvae were fed at least about three times per week with a commercial ornamental fish food extract as used for the breeding. An appropriate amount of this suspension (about 0.5 - 1 mg food/Larvae/day) was added to each test container.

- Method of cultivation:
For breeding the midges were kept in cages (60 x 60 x 55 cm), with a gauze on each side of the cage. A basin (45 x 55 x 10 cm) made of inert plastic was set on the bottom of each cage. The bottom of the basins were covered with a thin layer of "Kieselgur" (silica) and a 2 - 3 cm high layer of reconstituted water M7 according to Elendt, which was aerated gently. To start a culture in the cage, 2 - 4 egg masses were placed into the prepared basin. The hatched larvae were fed with green algae and an aqueous suspension of a vegetable fish food. After 2 to 3 weeks the adults emerged. After mating, female adults laid egg masses on the water surface where these could be taken to start a new culture or to perform toxicity tests.
The culture conditions were 20 ± 2°C and 16 to 8 hours light-dark-cycle (light intensity ca. 500 - 1000 lux).

Study type:

laboratory study

Test type:

static

Water media type:

other: M7-medium, based on de-ionised water

Type of sediment:

artificial sediment

Limit test:

no

Duration:

28 d

Exposure phase:

total exposure duration

Hardness:

267.0 to 320.4 mg CaCO3/L

Test temperature:

Water temperature ranged from 19.8°C to 20.3°C

pH:

Water pH values ranged from 7.2 to 8.7

Dissolved oxygen:

Dissolved oxygen concentrations ranged in the water phase from 6.9 to 8.7 mg O2/L (7.8 mg O2/L= 86 % O2 - saturation)

Nominal and measured concentrations:

The nominal concentrations in the overlying medium (spiked water application) were 0.176, 0.35, 0.70, 1.41, 2.81, 5.63, 11.3, and 22.5 mg form./L corresponding to 0.125, 0.25, 0.50, 1.00, 2.00, 4.00, 8.00, and 16.0 mg a.s./L of a water-sediment system.

Details on test conditions:

No. of replicates: 4 (for biological evaluations)
No. of larvae per replicate: 20
Size of test vessels: 0.6 L glass beakers (Ø 9.5 cm)
Temperature: mean 20 °C (min 18 °C, max 22 °C)
Light intensity: 500-1000 lux5
Light regime: 16 to 8 hours (light to dark)
Aeration: Test vessels were aerated during the equilibration phase. The aeration of the water was stopped for 24 hours after insertion of test organisms and re-started just before application of the test item. Gentle aeration was provided through a glass Pasteur pipette situated about 2.5 cm above the sediment layer throughout the complete study over 28 days (approximately 2 bubbles per second). Test beakers were covered by clear plastic plates, preventing evaporation.
Stock- Application- solution:
534.1 mg Propineb WP 70/ L, freshly prepared with test medium (M7). The stock solution was stirred on a magnetic stirrer for 2 minutes. In order to establish the selected test item concentrations, appropriate amounts of
the application solution were applied into the overlying water column of the vessels as a singular event on study day 0, just below the water surface with a pipette by gently mixing of the water body ensuring homogeneous
distribution of the test item without disturbance the sediment.

Reference substance (positive control):

no

Key result

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

emergence rate

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

0.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

emergence rate

Key result

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

22.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

development rate

Key result

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

3.55 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

emergence rate

Details on results:

Study was performed with the formulated product Propineb WP 70.
The EC50 value based on nominal initial concentrations in the overlying water and the emergence ratio was 4.99 (95% CL.: 1.83 – 16.2) mg form./L and the EC50 value based on nominal concentrations and the development rate was 31.8 (95% CL.: 20.7 – 59.2) mg form./L. The LOEC and NOEC values were 1.41 and 0.70 mg form./L respectively, based on the nominal concentrations and the emergence rate.

Other observations:
Abnormal observations (e.g. dead larvae or pupae, which failed to show full development and to emerge) throughout the study were observed on days 16, 17 and 19 for the control and the test concentrations of 0.176 and 0.35 mg form./L. Only few midges failed to emerge, thus a treatment related effect seems not to be likely. If dead adult midges were found on the water surface, it could be caused by the small space between the water surface and the coverage of the beakers.

Reported statistics and error estimates:

Sex ratio:
The c2-test (a = 0.05) established no statistical significant difference in numbers of emerged midges per sex up to the test level of 11.3 mg form./L. Therefore males and female were pooled for all further endpoint calculations to increase the statistical power.

Emergence ratio:
The %-emergence of midges in the control(s) fulfilled the guideline requirements: 96.3 % of the inserted larvae maturated to adults in the control.
Because it was not possible to introduce the same number of female and male organisms as larvae into each test beaker, the emergence rate of male and female numbers were pooled for all further the statistical analysis. On day 26 the daily count of emerged midges was not possible because of technical reasons. Thus the numbers of emerged midges counted on day 27 were divided in two equal parts, allocated to day 26 and to day 27. This procedure could lead to negligible deviations in calculation of the development-rate or –time, but this was not affecting the outcome of the study adversely.

Development rate:
Start of emergence in the control(s) was on day 14, last emergence occurred on day 27. So, the mean control development time met the criteria of validity.
A statistical significance was evaluated for all test concentrations, thus the NOEC was not reached. According to the guideline an extended ECx approach was used to express the results in a acceptable way.

Development rate in Chironomus riparius Males and Females as dependent on concentration of the test item and time; Mean: arithmetic mean; Std.Dev.: standard deviation; n: number of replicates; CV: coefficient of variation (calculated from InputRawDataAll)

Treatm. [mg form./L]	control	0.176	0.350	0.700	1.410	2.810	5.630	11.300
28 d	0.065	0.059	0.056	0.057	0.053	0.050	0.045	0.038
	0.066	0.059	0.058	0.059	0.054	0.051	0.047	0.041
	0.063	0.060	0.057	0.056	0.054	0.050	0.045	0.038
	0.061	0.060	0.059	0.058	0.056	0.054	0.045	0.038
Mean:	0.064	0.060	0.058	0.057	0.055	0.051	0.046	0.039
Std.Dev.:	0.0020	0.0008	0.0014	0.0015	0.0013	0.0017	0.0012	0.0014
n:	4	4	4	4	4	4	4	4
CV:	3.1	1.4	2.5	2.6	2.3	3.3	2.6	3.5

 

Emergence Rate of Males and Females of Chironomus riparius. Failure of emergence caused by the test item at 28 d.

Treatm. [mg form./L]	Introduced	Emerged	Not-emerged	% Not-emerged
control	80	77	3	3.8
0.176	80	70	10	12.5
0.350	80	66	14	17.5
0.700	80	72	8	10.0
1.410	80	59	21	26.2
2.810	80	62	18	22.5
5.630	80	54	26	32.5
11.300	80	16	64	80.0
22.500	80	0	80	100.0

The control mortality of 3.8% will be compensated using Abbott`s formula.

Validity criteria fulfilled:

yes

Conclusions:

The EC50 value based on nominal initial concentrations in the overlying water and the emergence ratio was 3.55 mg a.s./L and the EC50 value based on nominal concentrations and the development rate was 22.6 mg a.s./L. The LOEC and NOEC values were 1.00 and 0.50 mg a.s./L respectively, based on the nominal concentrations and the emergence rate.

Executive summary:

The aim of the study was to determine the influence of the test item on emergence and development of Chironomus riparius for 28-days in a static water-sediment system (spiked water exposure).

First instar of Chironomus riparius larvae, 4 beakers per test concentration and control (with 20 animals each) were exposed to initial nominal concentrations in the overlying medium of 0.125, 0.25, 0.50, 1.00, 2.00, 4.00, 8.00 and 16.0 mg a.s./L.

The EC₅₀ value based on nominal initial concentrations in the overlying water and the emergence ratio was 3.55 mg a.s./L and the EC₅₀ value based on nominal concentrations and the development rate was 22.6 mg a.s./L. The LOEC and NOEC values based on nominal concentrations and the emergence rate were 1.00 and 0.50 mg a.s./L.

Description of key information

The aim of the study was to determine the influence of the test item on emergence and development of Chironomus riparius for 28-days in a static water-sediment system (spiked water exposure).

The NOEC (emergence) value based on nominal initial concentrations in the overlying water and the emergence ratio was 0.50 mg a.s./L.