diethyl 1-(2,4-dichlorophenyl)-5-methyl-4,5-dihydro-1H-pyrazole-3,5-dicarboxylate

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

fish, juvenile growth test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 Mar - 29 Apr 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 215 (Fish, Juvenile Growth Test)

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: To obtain fresh stock solution for the test, the test substance was weighed out to a precision of 0.1 mg and dissolved in acetone. This stock solution (ss1) was filled up to the final volume with deionized water. Defined amounts of stock solution were diluted with defined amounts of acetone and deionized water to prepare the stock solutions for each concentration. These solutions were freshly prepared daily and given for approximately 15 min. into an ultrasonic bath for degassing. The solutions were filled into separate flasks for the different concentrations. Automatic dosage pumps intermittently added exact amounts of these solutions into the water-flow to the treated tanks.
- Chemical name of vehicle: Acetone of analytical grade quality (Riedel-de Haen, D-30981 Seelze, Art.no. 32201, assay 99.5%, lot 10770) was used as a solvent with 0.1 mL water.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Strain: Oncorhynchus mykiss WALBAUM
- Source: Oeseder Forellenzucht, Dr. Rosengarten, D-49124 Georgsmarienhuette
- Age at study initiation: 4 month
- Weight at study initiation (mean and range, SD): 1.22 + 0.1 g
- Method of breeding: Eggs and fish were hatched and maintained in accordance with the procedure described by Brauhn, Schoettger and Mueller (1975) in fibre-glass tanks.


FEEDING DURING TEST
- Food type: Commercial, pelleted dry fish food was given (KRONEN-FISH FB-50, Roth, 35274 Kirchhain, FRG)
- Amount: rate of 4% of their wet body weight per day during the test.
- Frequency: The daily ration was divided into two equal portions and given to the fish in two feeds per day

ACCLIMATION
As the holding conditions are very similar to the test conditions the fish were not specially
acclimated to the exact test conditions in order to avoid any disturbances that may change
the behaviour of the fish.

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

28 d

Hardness:

total hardness mg/L as CaCO3: 314 - 351

Test temperature:

15 ± 1 °C

pH:

7.6 - 8.0

Dissolved oxygen:

9.6 + 0.5 mg/L

Nominal and measured concentrations:

Nominal concentrations of untreated control, solvent control (0.1 mL acetone/L water),
0.01, 0.032, 0.1, 0.32, and 1.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: Stainless steel tanks containing 50 L water
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): From the storage tank 350 mL aerated and temperated water flowed per minute through glass tubes into the tanks resulting in a water renewal rate of 0.42 h (max: 0.44, min: 0.41).
- No. of organisms per vessel: 20
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1
- Biomass loading rate: 0.49 g/L


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The dilution water was purified drinking water (100% sand and charcoal filtered tap water)
- Intervals of water quality measurement: The water temperature of all tested concentrations and the control groups was recorded continuously
during the whole test period. Dissolved oxygen, pH, water temperature, conductivity and flow-rate were determined initially and every 24 hours thereafter for each of the test tanks


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: The light-dark cycle was 16L/8D.



EFFECT PARAMETERS MEASURED : The fish were examined daily during the test period of 28 days and any abnormal behaviour (intoxication symptoms) was noted. Mortality was recorded at 24 h intervals. Weight and length of the fish were determined at the experimental start day, at day 14 and at
the end of the test at day 28


VEHICLE CONTROL PERFORMED: yes

Reference substance (positive control):

not specified

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

and all other symptoms

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

0.32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

behaviour

Remarks:

: slow reactions, food consumption, staggering movements

Duration:

28 d

Dose descriptor:

LC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

28 d

Dose descriptor:

other: MATC (Maximal Acceptable Toxicant Concentration)

Effect conc.:

0.18 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

and all other symptoms

Remarks on result:

other: 28 day MATC: 0.1 - 0.32 mg/L

No effect occurred at the threshold concentration (0.1 mg/L) for chronic aquatic toxicity. First effects were seen at the next higher test concentration (0.32 mg/L). Therefore the Maximal Acceptable Toxicant Concentration (MATC) in this study was determined to be 0.18 mg/L (geometric mean of 0.1 – 0.32 mg/L). Thus it is reasonable to assume that the real NOEC lies above 0.1 mg/L.

Description of key information

NOEC (28 d) = 0.1 mg/L with Oncorhynchus mykiss (nominal, OECD 215)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.1 mg/L

Additional information

One key study on the parent substance were conducted in order to evaluate the effects of long-term toxicity to fish. All studies referred to herein were conducted in accordance with respective OECD testing guidelines and GLP. All effect values are reported as nominal.

In the key study a 28-day Juvenile Fish Growth Test according to OECD 215 was conducted under flow-through conditions with the rainbow trout (Oncorhynchus mykiss, 1994). Concentrations tested were in the range of 0.01 to 1.0 mg/L. Acetone was used as vehicle. In this test no effect was observed up to the concentration of 0.32 mg/L for 11 days. At day 12 effects started to occur, but disappeared after day 23. The NOEC (28 d) of 0.1 mg/L was established based on these temporary effects at 0.32 mg/L, the Lowest Observable Effect Concentration (LOEC). Mortality did not occur at any of the concentrations tested. The Maximal Acceptable Toxicant Concentration (MATC) is reported to be 0.18 mg/L (geometric mean of 0.1 – 0.32 mg/L).

Supporting information on the toxicity of two different metabolites of the test item is available.

A study on a metabolite was conducted according to OECD 215 under flow-through conditions with the rainbow trout (Oncorhynchus mykiss) (2004). Concentrations tested ranged from 0.32 to 32 mg/L. The NOEC (28 d) was determined to be 32 mg/L (nominal) based on mortality and growth.

Two further studies with a metabolite using Danio rerio and a flow-through test design are available (2005 a and b). One study was conducted according to OECD 212 with an exposure period of 8 days and test concentrations ranging from 1 – 100 mg/L. A NOEC (8 d) of 10 mg/L (nominal) was determined based on mortality (2005a). The second study followed an OECD draft guideline for a two generation study and lasted for 206 days with testing concentrations between 1 and 10 mg/L (2005b). The study resulted in a NOEC (206 d) of 3.2 mg/L (nominal) due to a lower ratio of F1 females at the highest concentration of 10 mg/L.