Benzamide, 4-methoxy-N-methyl-3-nitro-

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

4-methoxy-N-methyl-3-nitrobenzamide

EC Number:

812-957-9

Cas Number:

333350-60-0

Molecular formula:

C9H10N2O4

IUPAC Name:

4-methoxy-N-methyl-3-nitrobenzamide

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Determination of the test item
The limit concentration and the control were analytically verified via HPLC-DAD in fresh media at the start of the exposure (0 hours) and in old media at the end of the exposure (48 hours). The method was validated prior to this study according to SANCO 3029/99 rev.4 (2000).

Sampling for the analytical
At the start of the exposure (0 hours), samples of the fresh media were taken after preparation of the limit concentration and analyzed. At the end of the exposure (48 hours), samples of the old media were taken from additional replicates, which were prepared with test media, but without daphnids. These additional replicates were incubated under test conditions until sampling.

Criteria for the analytical monitoring (target)
Recoveries of the test item should be within ± 20% of the nominal or initially measured concentration.

Test solutions

Vehicle:

no

Details on test solutions:

Limit concentration
A limit concentration of 100 mg/L of the test item was tested. The limit concentration is based on the results of a non-GLP preliminary range finding test.

Preparation of the test concentration
The limit concentration (100 mg/L test item were weighed out) was prepared with dilution water one day prior to the start of the exposure (at -25 hours). The limit concentration was treated with ultrasound for 1 hour at 40 °C and stirred thereafter with a magnetic stirrer at approximately 1100 rpm for 24 hours at room temperature.

Control
Dilution water without test item incubated under the same conditions as the test group

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Test system
Daphnia magna STRAUS (Clone 5)

Reason for the selectionof the test system
Daphnia magna is the preferred species in accordance with the
test guideline and is bred at the test facility.

Origin
Institut für Wasser-, Boden- und Lufthygiene (WaBoLu),
14195 Berlin, Germany

Breeder
Noack Laboratorien GmbH,
Käthe-Paulus-Str. 1, 31157 Sarstedt, Germany

Culture
In glass vessels (2 - 3 L capacity) with approximately 1.8 L culture medium, at 20  2 °C, in an incubator, 16 hours illumination; light intensity of max. 1500 lx

Culture medium
Elendt M4, according to OECD 202, Annex 3 (2004), modified to a total hardness of 160 to 180 mg CaCO3/L, is used.

Culture feeding
The culture daphnids were fed at least 5 times per week ad libitum with a mix of unicellular green algae, e.g. Pseudokirchneriella subcapitata and Desmodesmus subspicatus, with an algae cell density of > 106 cells/mL. The algae were cultured at the test facility.

Origin of the food algae
Sammlung von Algenkulturen (SAG),
Pflanzenphysiologisches Institut der Universität Göttingen, Nikolausberger Weg 18, 37073 Göttingen, Germany

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

see any other information on material and methods incl. tables

Test temperature:

see any other information on material and methods incl. tables

pH:

see any other information on material and methods incl. tables

Dissolved oxygen:

see any other information on material and methods incl. tables

Conductivity:

see any other information on material and methods incl. tables

Details on test conditions:

Test method
The study was performed with a static test design.

Test duration
48 hours

Test vessels
Glass beakers (4 (ID) x 7 (H) cm), 50 mL capacity, loosely covered with watch glasses

Test volume
20 mL in each test replicate (see ‘Application’)

Dilution water
Same as culture medium

Number of daphnids and replicates
20 daphnids, divided into 4 replicates, each with 5 daphnids, were used for each loading level and the control.

Age of the daphnids
Less than 24 hours old daphnids from a healthy stock were used for at the start of the exposure the study. Juvenile daphnids were removed from the culture vessels at the latest 24 hours before the start of the exposure and discarded. The juveniles born within the following period of max. 24 hours preceding the exposure were used for the test. No first brood progeny was used for the test.

Acclimatization
Acclimatization of the daphnids was not necessary, because the dilution water was equivalent to the culture medium.
 
Application
20 g test solution per replicate was weighed out into each test vessel. This corresponds to 20 mL per test vessel. The daphnids were inserted with a small amount of dilution water by a pipette.

Test temperature (target)
18 - 22 °C, constant within ± 1 °C

Illumination (target)
Diffuse light, light intensity of max. 1500 lx

Photoperiod (target)
16/8 hours light/dark cycle

Feeding
The daphnids were not fed during the study.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

other: EC10/50/100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

other: EC10/50/100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

The percentage of immobility for the reference item potassium dichromate (SIGMA-ALDRICH, batch number MKBV0900V, purity 99.0%, CAS RN 7778-50-9) was determined after 24 hours from 2017 03-09 to 2017-03-10. For results of the most recent of the monthly performed reference tests, see Table 8.

EC50-Value (with 95% confidence limits) of the Reference Item Potassium dichromate based on nominal concentrations mg/L, (0 - 24 hours)
Current Study Valid Range
EC50 2.05 mg/L
0.6 - 2.4 mg/L, acc. to AQS P 9/2 (02/2000); clone 5
0.6 - 2.1 mg/L, acc. to OECD 202 (2004); clone A
95% confidence limits 2.00 - 3.71 mg/L

Reported statistics and error estimates:

Methods of evaluation
The effects of the limit concentration were empirically derived from the observed immobilization rates.
Since the measured test item concentrations were within ± 20% of the nominal concentration, all effect concentrations (EC10 / 50 / 100) given were based on the nominal concentration of the test item 4-Methoxy-N-methyl-3-nitrobenzamide.

EC-values and statistical analyses for reference item
An EC50-value was calculated for the reference item by sigmoidal dose-response regression. The respective 95% confidence limits were calculated from the standard error and the t-distribution. All calculations were carried out from the best-fit values with the software GraphPad Prism5.

Software
All data were computer-processed and rounded for presentation. Consequently, minor variations may occur from the original figures if manual calculations based on the original figures are made subsequently. Calculations were made using the following software:
- GraphPad Prism5, GRAPHPAD SOFTWARE, INC.
- Excel, MICROSOFT CORPORATION

Any other information on results incl. tables

Immobilization Rates [%]after 24 and 48 hours ofExposure in the Definitive Test

                (n = 20, divided into 4 replicates with 5 daphnids each)

Nominal test item concentration [mg/L]	IMMOBILIZATION [%]
	24 hours					48 hours
	Replicates					Replicates
	1	2	3	4	MV	1	2	3	4	MV
100	0	0	0	0	0	0	0	0	0	0
Control	0	0	0	0	0	0	0	0	0	0

 

 

 Absolute Numbers of immobileDaphnids after 24 and 48 hours ofExposure in the Definitive Test

                (n = 20, divided into 4 replicates with 5 daphnids each)

Nominal test item concentration [mg/L]	Number of immobile Daphnids / Total number of Daphnids
	24 hours					48 hours
	Replicates					Replicates
	1	2	3	4	MV	1	2	3	4	MV
100	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20
Control	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In the limit concentration 100 mg/L of the test item 4-Methoxy-N-methyl-3-nitrobenzamide, no effects on Daphnia magna were observed.

Executive summary:

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the limit concentration of 100 mg/L of the test item 4-Methoxy-N-methyl-3-nitrobenzamide were determined at the test facility according to OECD 202 (2004) .

The limit test was conducted under static conditions over a period of 48 hours.The limit concentration was visually clear throughout the exposure period. Twenty daphnids, divided into 4 replicates with 5 daphnids each, were exposed to the limit concentration and the control.

The concentration of the test item 4-Methoxy-N-methyl-3-nitrobenzamide was analytically verified via HPLC-DAD in fresh media at the start of the exposure (0 hours) and in old media at the end of the exposure (48 hours) in the limit concentration and in the control.

The measured concentration in the limit concentration was 100% of the nominal concentration in fresh medium at the start of the exposure (0 hours) and 99% of the nominal concentration in old medium at the end of the exposure (48 hours).

The measured test item concentrations were within ± 20% of the nominal concentration. This indicates that the test item concentration was successfully maintained for the duration of the test. Therefore, the effect concentrations given are based on the nominal concentration of the test item4-Methoxy-N-methyl-3-nitrobenzamide.

The validity criteria of the test guideline were fulfilled.

 

 EC_{10 / 50 / 100}-Values (based on the nominal concentration of the test item)

Effect Concentrations	Test duration [h]	4-Methoxy-N-methyl-3-nitrobenzamide Nominal test item concentration [mg/L]
EC10 / 50 / 100	24	> 100
	48	> 100