Naphthalenesulfonic acid, dibutyl-, Me derivs., sodium salts

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

from 2017-05-29 to 2017-06-30, with the definitive exposure phase from 2017-05-30 to 2017 06 01

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The data is read across from a similar substance in a category approach. See chapter 13 for more details

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Determination of the test item
The limit test item 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).

Sampling for the analytical monitoring
At the start of the exposure (0 hours), samples of the fresh media were taken after preparation of the limit test item concentration and analyzed. At the end of the exposure (48 hours), samples of the old media were taken directly from the test vessels and analyzed.

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

Vehicle:

no

Details on test solutions:

Limit test item concentration
A limit test item concentration of 100 mg/L was prepared. The limit concentration is based on the results of a non-GLP preliminary range finding test conducted at the test facility under static conditions.

Water Accommodated Fraction (WAF)
In view of the difficulties associated with the evaluation of aquatic toxicity of poorly water soluble test items, complex mixtures and UVCB substances, a modification of the standard method for the preparation of aqueous media will be performed. An approach endorsed by several important regulatory authorities in the EU and elsewhere (ECETOC 1996 and OECD 2000) is to expose the organisms to a water accommodated fraction (WAF) of the test item in cases where the test item is a complex mixture and is poorly soluble in water and in the permitted solvents. Using this approach, aqueous media were prepared by mixing the test item with water for a prolonged period sufficient to ensure equilibration between the test item and the water phase. After completion of mixing and following a settlement period, the test item phase was separated by siphon and the test organisms were exposed to the aqueous phase, the WAF (which may contain dissolved and/or suspended and/or emulsified fractions of the test item mixture). Exposure is expressed in terms of the concentration of the test item in water at the start of the mixing period (loading concentration).

Since the test item is labeled as UVCB but water solubility is above the limit loading concentration, the WAF approach used for media preparation can actually be considered to be a true solution of the test item.

Preparation of the limit test concentration
The limit test item concentration was prepared with a concentration of 100 mg/L one day prior to the start of the exposure (at -24 hours) as specified below.
An appropriate amount of the test item was weighed out on a glass slide and transferred into a brown glass flask with an appropriate amount of dilution water. This dispersion was shaken for 24 hours with 20 rpm at room temperature. After completion of shaking and following a separation phase of at least 1 hour of standing, the aqueous phase was removed from the approximate center of the water body by siphoning. The limit test item concentration was checked via laser beam (Tyndall effect) for undissolved test item (formation of emulsion).

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

Test organisms (species):

Daphnia magna

Details on test organisms:

Test system
Daphnia magna STRAUS (Clone 5).

Reason for the selection of 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. 20 µEm-2  s-1

Culture medium
Elendt M4, according to ELENDT (1990), modified to a total hardness of 160 to 180 mg CaCO3/L, was used. The composition of the culture medium is presented in Table 2.

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


Composition of the Culture Medium according to ELENDT (1990)
Component Concentration [mg/L]
CaCl2 x 2 H2O 147
MgSO4 x 7 H2O 123
KCl 5.80
NaHCO3 64.8
Na2SiO3 4.30
NaNO3 0.27
KH2PO4 0.14
K2HPO4 0.18
Na2EDTA x 2 H2O 5.00
FeSO4 x 7 H2O 1.99
H3BO3 0.29
MnCl2 x 4 H2O 0.36
LiCl 0.30
SrCl2 x 6 H2O 0.15
RbCl 0.071
NaBr 0.016
Na2MoO4 x 2 H2O 0.063
CuCl x 2 H2O 0.017
ZnCl2 0.013
CoCl2 x 6 H2O 0.010
KJ 0.00325
Na2SeO3 0.00219
NH4VO3 0.000575
Thiaminhydrochloride 0.075
Cyanocobalamine 0.0010
Biotin 0.00075
pH 8.2  0.8

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

Dilution water
0 hours:Total hardness [mg CaCO3/L]: 160

Test temperature:

18 - 22°C, constant within ± 1°C
20.8 °C

pH:

Water Quality Parameters in the fresh Media at the Start of the Exposure (0 hours)
(measured in one additional replicate (without daphnids) of the limit concentration and the control)
Nominal concentration
of the test item
[mg/L] pH-Value Dissolved O2-Concentration [mg/L]
100 7.65 8.74
Control 8.06 9.56


Water Quality Parameters in the old Media at the End of the Exposure (48 hours)
(measured in all replicates(containing daphnids) of the limit concentration and the control)
Nominal concentration
of the test item
[mg/L] pH-Values Dissolved O2 -Concentration [mg/L]
Replicates Replicates
1 2 3 4 1 2 3 4
100 7.96 7.99 7.96 7.94 8.43 8.44 8.38 7.82
Control 8.16 8.02 8.00 8.01 7.47 7.10 7.88 7.85

Dissolved oxygen:

see above

Conductivity:

Dilution water day 0: 430 [µS/cm]

Details on test conditions:

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 daphnidsat the start of the exposure
Less than 24 hours old daphnids from a healthy stock were used for
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 was not necessary, because the dilution water was equivalent to the culture medium.

Application
20 g test solution per replicate were 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 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.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

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

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 05-04 to 2017-05-05.

EC50-Value (with 95% confidents 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 1.80 - 2.33 mg/L

Reported statistics and error estimates:

Methods of evaluation
The effects of the limit concentration were empirically derived from the observed immobilization rates.
All effect levels (EC10 / 50 / 100) were based on the nominal concentration of the test item Naphthalenesulfonic acid, bis(1-methylethyl)-, methyl dervis., sodium salt.

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

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

Immobilization Ratesafter 24 and 48 hours ofExposure in the Definitive Test

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

Naphthalenesulfonicacid, bis(1-methylethyl)-, methyl dervis., sodium salt   Nominal concentration of the test item [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)

Naphthalenesulfonicacid, bis(1-methylethyl)-, methyl dervis., sodium salt   Nominal concentration of the test item [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

 

Validity criteria fulfilled:

yes

Conclusions:

Based on the nominal concentration of the test item Naphthalenesulfonic acid, bis(1-methylethyl)-, methyl dervis., sodium salt, the 48 hour EL50 for Daphnia magna was > 100 mg/L.

Executive summary:

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test itemNaphthalenesulfonic acid, bis(1-methylethyl)-, methyl dervis., sodium salt (batch number:1452486) were determined at the test facility according to OECD 202 (2004) from2017-05-29 to 2017-06-30, with the definitive exposure phase from 2017-05-30 to 2017‑06‑01.

The test item is asubstance of unknown or variable composition (UVCB). Due to the complex nature of the test item for the purposes of the test, the test item was prepared following the protocol of water accommodated fraction (WAF). Since the water solubility of the test item is above the tested limit concentration, the test solution is considered to be true solution at loading level. Therefore, the limit loading will be considered as the actual test item concentration throughout this report.

The study wasperformedunder static conditions over a period of 48 hours withoneconcentration of the test item prepared as a limit test item concentration of100 mg/L.All concentrations were visually clear throughout the exposure period and showed no Tyndall effect.

The concentrations of the test itemNaphthalenesulfonicacid, bis(1-methylethyl)-, methyl dervis., sodium saltwereanalytically verified via UPLC-DAD in fresh media at the start of the exposure (0 hours) and the end of the exposure (48 hours) in the limit concentration and the control. Recoveries of the test item were in the range of 99 % at the start and end of exposure.

The measured concentration of the test item was within±20% of the nominal concentration.

In view of substances labeled as UVCB, all terms related to concentration levels should be given as loading levels because partly dissolved compounds and mixtures cannot be related to concentrations. However, since the limit test item concentration is below the certified water solubility and analytical recoveries of the main constituents were within nominal range, the EC_{10 / 50 / 100}-values given inTable1werebased on the nominal test item concentration.

The validity criteria of the test guidelines were fulfilled.

 

EC₁₀-, EC₅₀- and EC₁₀₀-Values based on Nominal Concentration of the Test Item

Effect values	Test duration [hours]	Naphthalenesulfonic acid, bis(1-methylethyl)-, methyl dervis., sodium salt Nominal concentration of the test item [mg/L]
EC10/ EC50/ EC100	24	> 100
	48	> 100

 

Description of key information

The acute toxicity of Naphthalenesulfonic acid, dibutyl-, Me derivs., sodium salts to daphnia is read across from the structurally related substance naphthalenesulfonic acid, bis(1-methylethyl)-, methyl derivatives, sodium salts.

In addition acute daphnia rangefinding tests have been performed with two batches of Aromatic Hydrocarbons, C10-13, Reaction Products With Branched Nonene Sulphonated, sodium salt to evaluate which of two relatively similar alkylnaphthalene sulphonates is the more toxic substance. The results obtained indicate that there is a slightly higher toxicity observed for the batch containing a higher fraction of long alkyl chain derivative when compared to the batch with a lower content of long alkyl chain derivative.

Comparable EC50 are observed in the acute daphnia test with naphthalenesulfonic acid, bis(1-methylethyl)-, methyl derivatives, sodium salts and Aromatic Hydrocarbons, C10-13, Reaction Products With Branched Nonene Sulphonated, sodium salt as for both EC50 values are observed of >100 mg/L. The study with naphthalenesulfonic acid, bis(1-methylethyl)-, methyl derivatives, sodium salts is however a complete study and the result as observed for this substance is therefore used for read across to those alkylnaphthalenesulphonates for which the acute daphnia data are missing.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

In the acute immobilization test withDaphnia magna(STRAUS), the effect of the test item Naphthalenesulfonic acid, bis(1-methylethyl)-, methyl dervis., sodium salt was determined according to OECD 202 (2004).

The test item is a substance of unknown or variable composition (UVCB). Due to the complex nature of the test item for the purposes of the test, the test item was prepared following the protocol of water accommodated fraction (WAF). Since the water solubility of the test item is above the tested limit concentration, the test solution is considered to be true solution at loading level. Therefore, the limit loading will be considered as the actual test item concentration throughout this report.

The study was performed under static conditions over a period of 48 hours with one concentration of the test item prepared as a limit test item concentration of 100 mg/L. All concentrations were visually clear throughout the exposure period and showed no Tyndall effect.

The concentrations of the test item Naphthalenesulfonicacid, bis(1-methylethyl)-, methyl dervis., sodium saltwereanalytically verified via UPLC-DAD in fresh media at the start of the exposure (0 hours) and the end of the exposure (48 hours) in the limit concentration and the control. Recoveries of the test item were in the range of 99 % at the start and end of exposure.

The measured concentration of the test item was within±20% of the nominal concentration.

In view of substances labeled as UVCB, all terms related to concentration levels should be given as loading levels because partly dissolved compounds and mixtures cannot be related to concentrations. However, since the limit test item concentration is below the certified water solubility and analytical recoveries of the main constituents were within nominal range, the EC_{10 / 50 / 100}- are therefore based on the nominal test item concentration.

 

Effect values	Test duration [hours]	Naphthalenesulfonic acid, bis(1-methylethyl)-, methyl dervis., sodium salt Nominal concentration of the test item [mg/L]
EC10/ EC50/ EC100	24	> 100
	48	> 100