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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
12/12/1996 - 23/09/1998
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to methodology comparable to OECD TG 202 in compliance with GLP, without deviations that influence the quality of the results.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: Nominal: 0.5, 0.75, 1.1, 1.7 and 2.5 mg/l
- Sampling method: Duplicated 10-ml samples of each new WAF solution were collected at 0 and 24 hours abd abalyzed for OTNE by LSC. Equal volumes of old test solutions were collected from both replicates of the control, vehicle blank, and each treatment level at 24 and 48 hours. The replicate samples from each treatment level and control were composited and duplicate 10-ml sub-samples were analyzed for OTNE by LSC.
- Sample storage conditions before analysis: No data
Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The dosing solution was an isotopic dilution containing 14C-CPD 98663 and OTNE. The solution was prepared by quantatively transferring a 1.0 mCi sample of 14C-CPD 98663 with OTNE to a volume of 10.0 ml. This standard solution was identified as PR-01554 and was analyzed by liquid scintillation counting (LSC) analysis to have an active ingredient concentration of 9.60 x 10^5 ug/ml. A 0.520-ml aliquot os this solution was brought to a 10.0 ml total volume with acetone to prepare the final dosing solution with a concentration of 4.00 x 10^4 ug/ml as analyzed by LSC. This solution was identified as R-01870 and was used to prepare all of the exposure solutions at each time periode.

Test solutions were prepared individually for each treatment by adding an appropriate amount of the 4.99 x 10^4 ug/ml dosing solution to 2.0 L of dilution water in a 2-L volumetric flask. An additional volume of acetone was added to levels 1-4 to produce acetone concentrations equal to that in level 5 (50 ul/l). Each flask contained a teflon-coated stir bar and the contents of the jars were stirred for 20 +/- 1 hours. Solutions were stirred so that a vortex <25% of volumetric depth was achieved. When stirring was terminated, the phases were allowed to seperate for 1-1.5 hours. A portion of the water phase (WAF) in each flask was removed via a glass siphon tube and used to fill the respective test chambers. New WAF solutions were prepared and used to renew the test solutions after 24 hours of exposure.
- Controls: yes, blanks and vehicle blanks
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): acetone
- Concentration of vehicle in test medium (stock solution and final test solution): 50 ul/l
- Evidence of undissolved material (e.g. precipitate, surface film, etc): No, phase were allowed to seperate for 1-1.5 hours after mixing after which only WAF's were used
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna
- Source: in-house culture
- Age at start of the test: Less than 24 hours
- Method of breeding: The adult daphnids were cultured in a temperature-controlled water bath at approximately 20 degrees Celsius. the culture room lighting was maintained on a 16-hour daylight photoperiod with 30-minute dusk/dawn transition periods. During the holding period, the adult daphnids in the culture were fed a suspension of the algal species Selenastrum capricornutum and Ankistrodesmus falcatus at least once a day supplemented by an artificial diet that was prepared according to ABC SOP AQ 1.1. The supplier of the fish food in the artificial diet was Rangen Inc. The adult daphnids that produced the neonates for definitive testing were isolated by transferring the adults to a fresh water/food suspension one day prior to neonate selection. The adults which produced the young for definitive testing were approximtely 20 days old and were considered acceptable with no signs of stress or physical damage.
- Feeding during test: no feeding during test


ACCLIMATION
- Acclimation period: None
- Acclimation conditions (same as test or not): same as test
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
148 mg/ CaCO3.
Test temperature:
19.7 - 20.5 degrees Celsius for new parent and replicate old solutions. 20.2 - 20.8 degrees Celsius for replicate new solutions.
pH:
7.7 - 8.1
Dissolved oxygen:
7.2 - 8.0 mg/l (83 - 92% saturation) for new solutions. 3.3 - 7.8 mg/l (38 - 90% saturation) for old solutions.
Nominal and measured concentrations:
Nominal: 0.5, 0.75, 1.1, 1.7 and 2.5 mg/l;
Measured (0h): 0.51, 0.782, 1.18, 1.81 and 2.63 mg/l; Measured (24h, old): 0.489, 0.759, 1.13, 1.74 and 2.57 mg/l
Measured (24h): 0.517, 0.733 1.08 mg/l; Measured (48h, old): 0.510, 0.748, 1.09 mg/l
Higher concentrations were discontinued due to 100% mortality.
Measured (mean): 0.51, 0.76, 1.1, 1.8 and 2.6 mg/l
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass, 237 ml, as little headspace as possible
- Aeration: No data
- Renewal rate of test solution (frequency/flow rate): once per 24 hours
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 2


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: mixture of naturally hard well water with well water demineralized by reverse osmosis.
- Organic content: <1.00 mg/l
- Metals:
AL < 0.044 mg/l
As 0.0057 mg/l
B 0.301 mg/l
Cd <0.00042 mg/l
Cr <0.0013 mg/l
Co <0.0058 mg/l
Cu <0.0045 mg/l
Fe <0.015 mg/l
Pb <0.0034 mg/l
Hg <0.000023 mg/l
Ni <0.0078 mg/l
Se <0.0037 mg/l
Ag <0.00081 mg/l
Zn 0.021 mg/l
- Pesticides: all <3.8 ug/l
- Alkalinity: 156 mg/l CaCo
- Conductivity: 314 uS/cm
- Culture medium different from test medium: No
- Intervals of water quality measurement: 24 hours


OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16/8 light/dark period
- Light intensity: 734.8 - 757.5 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality and sublethal response were recorded every 24 hours


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.5
- Range finding study
- Test concentrations: 0.1, 1.0 and 10 mg/l; 1.0, 2.5 and 5.0 mg/l
- Results used to determine the conditions for the definitive study: After 48 hours of exposure during the first test mortality was 0% at 1.0 mg/l and 100% at 1.0 and 10.0 mg/l. After 24 hours of exposure during the second test, mortality was 10% at 1.0 mg/l and 100% at 2.5 and 5.0 mg/l.
Reference substance (positive control):
no
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
1.38 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
other: radioactive compound
Basis for effect:
mobility
Remarks on result:
other: 1.32-1.44
Details on results:
- Mortality of control: 0%
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: No
Reported statistics and error estimates:
Statistical analysis of the concentration versus effect data (immobility) was performed by a computerized EC50 program using Trimmed Spearman-Karber techniques. The slope of the concentration-response line was calculated by transforming percent immobility/mortality to probit values and plotting probit values against the log of the concentration. Linear regression was used for the calculation of the slope of the concentration-response line. The slope of the dose-response line was 12.77.
Validity criteria fulfilled:
yes
Remarks:
0% mortality in controls, oxygen concentration > 3 mg/l during the test
Conclusions:
The 48h-EC50 of OTNE towards Daphnia magna is 1.38 mg/l.
Executive summary:

The toxicity of OTNE towards Daphnia magna was investigated according to a protocol similar to OECD Guideline 202, under GLP. Daphnia were exposed to water accommodated fractions (WAF) of 14C-labeled OTNE with nominal concentrations of 0.50, 0.75, 1.1, 1.7 and 2.5 mg/l in a semi-static system and observed for 48 hours. Validity criteria for the test were met. The 48h-EC50 was found to be 1.38 mg/l (95% CL 1.32 -1.44 mg/l) based on mean measured concentrations.

Description of key information

The toxicity of OTNE towards Lepomis macrochirus was investigated according to methodology comparable to OECD Guideline 203 under GLP. Fish were exposed to water accommodated fractions (WAF) of 14C-labelled OTNE with nominal concentrations of 0.50, 0.75, 1.1, 1.7 and 2.5 mg/l in a semi-static system and observed for 96 hours. Validity criteria for the test were met. The 96h-LC50 was found to be 1.3 mg/l (95% CL 1.2 - 1.5 mg/l) based on mean measured concentrations.
    
    
    

The toxicity of OTNE towards Daphnia magna was investigated according to a protocol similar to OECD Guideline 202, under GLP. Daphnia were exposed to water accommodated fractions (WAF) of 14C-labeled OTNE with nominal concentrations of 0.50, 0.75, 1.1, 1.7 and 2.5 mg/l in a semi-static system and observed for 48 hours. Validity criteria for the test were met. The 48h-EC50 was found to be 1.38 mg/l (95% CL 1.32 -1.44 mg/l) based on mean measured concentrations.

The toxicity of OTNE towards Daphnia magna was investigated according to a protocol similar to OECD Guideline 202, under GLP. Daphnia were exposed to water accommodated fractions (WAF) of 14C-labeled OTNE with nominal concentrations of 0.50, 0.75, 1.1, 1.7 and 2.5 mg/l in a semi-static system and observed for 48 hours. Validity criteria for the test were met. The 48h-EC50 was found to be 1.38 mg/l (95% CL 1.32 -1.44 mg/l) based on mean measured concen

The toxicity of OTNE towards Daphnia magna was investigated according to a protocol similar to OECD Guideline 202, under GLP. Daphnia were exposed to water accommodated fractions (WAF) of 14C-labeled OTNE with nominal concentrations of 0.50, 0.75, 1.1, 1.7 and 2.5 mg/l in a semi-static system and observed for 48 hours. Validity criteria for the test were met. The 48h-EC50 was found to be 1.38 mg/l (95% CL 1.32 -1.44 mg/l) based on mean measured concentrations.

The toxicity of OTNE towards Daphnia magna was investigated according to a protocol similar to OECD Guideline 202, under GLP. Daphnia were exposed to water accommodated fractions (WAF) of 14C-labeled OTNE with nominal concentrations of 0.50, 0.75, 1.1, 1.7 and 2.5 mg/l in a semi-static system and observed for 48 hours. Validity criteria for the test were met. The 48h-EC50 was found to be 1.38 mg/l (95% CL 1.32 -1.44 mg/l) based on mean measured concentrations.

The toxicity of OTNE towards Daphnia magna was investigated according to a protocol similar to OECD Guideline 202, under GLP. Daphnia were exposed to water accommodated fractions (WAF) of 14C-labeled OTNE with nominal concentrations of 0.50, 0.75, 1.1, 1.7 and 2.5 mg/l in a semi-static system and observed for 48 hours. Validity criteria for the test were met. The 48h-EC50 was found to be 1.38 mg/l (95% CL 1.32 -1.44 mg/l) based on mean measured concentrations.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
1.38 mg/L

Additional information