Naphthalenesulfonic acid, di-C9-rich C8-10-branched alkyl derivs., barium salts

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Start : 23 May 2012 Completion : 25 May 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Samples for possible analysis were taken from all test concentrations and the control according to the
schedule below. In addition, glass wool containing undissolved residue was kept for possible analysis.
Frequency at t=0 h and t=48 h
Volume 2 ml from the approximate centre of the test vessels
Storage Samples were stored in a freezer until analysis.
At the end of the exposure period, the replicates were pooled at each concentration before sampling.
Additionally, reserve samples of 2 ml were taken for possible analysis. If not used, these samples
were stored in a freezer for a maximum of three months after delivery of the draft report, pending on
the decision of the sponsor for additional analysis.

Vehicle:

no

Details on test solutions:

Preparation started with individual loading rates of 1.0, 10 and 100 mg/l. A 2-day period of magnetic stirring was applied. The obtained solutions were filtered through a 0.45 µm membrane filter (RS55, Whatman). The lowest test concentration as prepared as a dilution of the filtrate prepared at a loading rate of 1.0 mg/l. The final test solutions were all clear and colourless.

Test organisms (species):

Daphnia magna

Details on test organisms:

Source: In-house laboratory culture with a known history.
Reason for selection: This system has been selected as an internationally
accepted invertebrate species.
Validity of batch: Daphnids originated from a healthy stock, 2nd to 5th brood,
showing no signs of stress such as mortality >20%,
presence of males, ephippia or discoloured animals and
there was no delay in the production of the first brood.
Characteristics: For the test selection of young daphnids with an age of < 24
hours, from parental daphnids of more than two weeks old.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

None

Hardness:

The hardness: 180 mg/l expressed as CaCO3 and the pH: 7.7 ± 0.3.

Test temperature:

The temperature of the test medium was 20.5°C at the start of the test. The temperature continuously
measured in a temperature control vessel varied between 19.9 and 20.8°C during the test, and
complied with the requirements as laid down in the protocol (18-22°C, constant within 2°C).

pH:

Day 0: 7.9
Day 2: 8.3

Dissolved oxygen:

Day 0: 9.1-9,5
Day 2: 8.3

Salinity:

NA

Nominal and measured concentrations:

See Table

Details on test conditions:

Test duration -- 48 hours
Test type -- Static
Test vessels -- 100 ml, all-glass
Medium -- Adjusted ISO medium
Number of daphnids -- 20 per concentration
Loading -- 5 per vessel containing 80 ml of test solution

Reference substance (positive control):

yes

Remarks:

potassium dichromate (K2Cr2O7)

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.18 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

A table of mortality is presented in the section below.

Results with reference substance (positive control):

See Table.

Reported statistics and error estimates:

EC50 could not be calculated due to insufficient mortality

          Acute immobilisation of daphnids after 24 and 48 hours

Barium bis( di C8-C10, branched, C9 rich, alkylnaphthalene sulphonate)

Test substance^1 Loading rate (mg/l)	Vessel number	Number Daphnia exposed	Response at 24 h		Response at 48 h
			number	Total %	number	Total %
control	A  B C D	5 5 5 5	0 0 0 0	0	0 0 0 0	0
10% of 1.0	A  B	5 5	0 0	0	0 0	0
1.0	A  B	5 5	0 0	0	0 0	0
10	A  B	5 5	0 0	0	0 0	0
100 (0.18)	A  B C D	5 5 5 5	0 0 0 0	0	0 0 0 0	0

1.Barium bis( di C8-C10, branched, C9 rich, alkylnaphthalene sulphonate)

() – initially measured concentration

Acute immobilization of daphnia after 24 and 48 hours in the reference test with potassium dichromate:

                                                                       

Concentration (mg/l)		Number Exposed	% immobile 24h                     48h		Expected response (%) After 48 hours^1
					Minimal            Maximal
control	20		0	0	0	10^2
0.10	20		0	0	0	10
0.18	20		0	0	0	10
0.32	20		0	85	0	30
0.56	20		75	95	0	100
1.0	20		100	100	40	100
1.8	20		100	100	100	100

¹ Based on historical data of the previous years (n>60).

² A maximum response of 10% does not invalidate the results of the test.

Validity criteria fulfilled:

yes

Conclusions:

The 48h-EC50 was beyond the range tested, i.e. exceeded the initially measured concentration of 0.18 mg/l (100 mg/L oading rate) .

Due to the very low solubility of Barium bis( di C8-C10, branched, C9 rich, alkylnaphthalene sulphonate) in water, concentration levels that might be toxic for algae could not be reached.

Executive summary:

An Acute Toxicity Study with Barium bis( di C8-C10, branched, C9 rich, alkylnaphthalene sulphonate) was conducted with Daphnia magna.The study procedures described in this report were based on the OECD guideline No. 202, 2004. The batch of Barium bis( di C8-C10, branched, C9 rich, alkylnaphthalene sulphonate) tested was a beige-brown crystalline powder with lumps. The substance is an UCVB material with purity of 100%. 

A combined limit range-finding test was performed. Preparation started with individual loading rates of 1.0, 10 and 100 mg/l. A 2-day period of magnetic stirring was applied. The obtained solutions were filtered through a 0.45 µm membrane filter (RS55, Whatman). The lowest test concentration as prepared as a dilution of the filtrate prepared at a loading rate of 1.0 mg/l. The final test solutions were all clear and colourless.

 

Twenty daphnids per group (5 per vessel, 4 vessels) were exposed to a control and a 0.45 µm filtered solution prepared at a loading rate of 100 mg/l, in the limit test. In addition, ten daphnids per group (5 per vessel, 2 vessels) were exposed to filtrates prepared at loading rates of 1.0 and 10 mg/l and to a solution containing 10% of the filtrate prepared at 1.0 mg/l, in the range-finding test. The total exposure period was 48 hours and samples for determination of exposure concentrations were taken at the start and at the end of the test. Analysis of the samples taken at the start of the test from the highest concentration showed measured concentration of 0.18 mg/l. The actual concentration remained stable during the entire period of exposure (95% of initial).

 

The study met the acceptability criteria prescribed by the protocol and was considered valid.

 

Barium bis( di C8-C10, branched, C9 rich, alkylnaphthalene sulphonate) did not induce acute immobilisation of Daphnia magna at an initially measured concentration of 0.18 mg/l after 48 hours of exposure (NOEC). The 48h-EC₅₀was beyond the range tested, i.e. exceeded the initially measured concentration of 0.18 mg/l. Due to the very low solubility of Barium bis( di C8-C10, branched, C9 rich, alkylnaphthalene sulphonate) in water, concentration levels that might be toxic for algae could not be reached.

Description of key information

The 48h-EC50 was beyond the range tested, i.e. exceeded the initially measured concentration of 0.18 mg/l (100 mg/L oading rate) .
When the free accid, DNNSA, was tested for acute toxicity to daphnia the 48-hour EC50 > 0.27 mg/L (measured).
Due to the very low solubility of di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA) in test medium, concentrations that might be toxic to Daphnia magna could not be reached.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.18 mg/L

Additional information

Due to the very low solubility of Barium bis( di C8-C10, branched, C9 rich, alkylnaphthalene sulphonate) in water, concentration levels that might be toxic for daphnia could not be reached. This finding was confirmed when testing DNNSA, the free acid, in an equivalent test with daphnia and also no toxicity was observed at maximum water solubility (0.27 mg/L in this test).

Based on the results found, which are similar for the acid and the salt, it can be concluded that data from the acid can be used for the salt in a read-across approach.