Sodium p-chloro-m-cresolate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The test substance concentration was not within ± 20% of nominal in day 2 and 16 in the lowest concentration)

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Ministerium für Umwelt und Naturschutz, Landwirtschaft und Verbraucherschutz des Landes Nordrhein-Westfalen, Düsseldorf, Germany

Analytical monitoring:

yes

Details on sampling:

- Concentrations:control, 0.01, 0.032, 0.1, 0.32 and 1.0 mg/L
- Sample storage conditions before analysis: No, analysed immediately

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Before the test item was weighed in it was treated with a mortar. A stock solution was prepared to give the desired series of test concentrations. To achieve this 10 mg of the test item were added to 2 L of dilution water, treated for 1 h in an ultrasonic bath and stirred for 1 h on a magnetic stirrer and heated for 10 min. on a heating surface at 50 °C. Finally undissolved particles of the test item were removed by filtration using folded filters of pore size 7-12 μm.
- Differential loading: no
- Controls: yes, water control

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: Strain of Bundesgesundheitsamt Berlin had been maintained in own laboratory (Bayer Industry Services)
- Age: < 24 hours
- Feeding during test: day 0-7: 0.1 mg C / Daphnia / day; day 8-21: 0.2 mg C / Daphnia / day
- Food type: Feeding was performed with green algae Desmodesmus subspicatus.
- Amount: ad libitum
- Frequency: ad libitum

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

14.6 - 15.9 dH (= 260.61 – 283.82 mg/L CaCO3)

Test temperature:

20.2 - 20.8 °C

pH:

7.8 - 8.1

Dissolved oxygen:

8.4 - 9.0 mg O2/L

Nominal and measured concentrations:

nominal: 0.01, 0.032, 0.1 and 1 mg/L. Recovery rates ranged from 91.5 to 100.6% of the nominal values in the freshly prepared media and from 59.5 to 96.3% in the aged media. Measured concentrations below 80% were only found in the lowest concentration of 0.01 mg/L (69.5% at day 2 and 59.5 at day 16).

Details on test conditions:

TEST SYSTEM
- Test vessel: 150 mL glass beakers
- Material, size, headspace, fill volume: glass, size: 150 mL, headspace: 50 mL, fill volume: 100 mL
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): three renewals of test medium per week
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water (“M4 medium”)

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hour light : 8 hours darkness
- Light intensity: not exceeding 800 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The mortality of adults and the number of neonates was observed three times per week at the renewals of the test media.

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

- Mortality of control: There was no mortality in the control. In the control the mean number of newborn water fleas per adult over the whole test period was 107 per replicate.
- Days to 1st brood: 7 d

Reported statistics and error estimates:

The results were statistically evaluated according to Welch-T test for inhomogenous variances with Bonferroni adjustement.

The results are expressed in terms of nominal concentrations. Recovery rates ranged from 91.5 – 100.6% of the nominal values in the freshly prepared media and from 59.5 – 96.3% in the media after 48 hours, 72 h of exposure, respectively. Recovery rates in the NOEC and above were >80%. Only in concentrations below the NOEC, which are not relevant to the overall study result, recoveries below 80% were found. Therefore all results are given as nominal concentrations

Table 1: Immobilisation/mortality rate of parent daphnids exposed to CMK (nominal concentrations)

Test item concentration [mg/L]	Immobilisation/mortality rate of parent Daphnia
	absolute	%
Control	0	0
0.01	0	0
0.032	0	0
0.1	0	0
0.32	0	0
1.0	0	0

Table 2: Mean number of offsprings per adult reproduced within 21 days

Test item concentration [mg/L]	Mean reproduction rate	Standard deviation	Coefficient of variation (%)
Control	107.0	8.6	8.0
0.01	114.0	8.7	7.6
0.032	107.6	11.0	10.2
0.1	107.3	13.1	12.2
0.32	105.7	7.4	7.0
1.0	80.2	13.2	16.4

Table 3: Validity criteria

Criterion from the guideline	Outcome	Validity criterion fulfilled
The mortality of the parent animals (femaleDaphnia) does not exceed 20% at the end of the test.	0 %	yes
The mean number of living offspring produced per parent animalsurvivingat the end of the test is ≥ 60.	107.0	yes

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Conclusions:

NOECreproduction (21 d) = 0.32 mg/L
LOEC reproduction (21 d) = 1.0 mg/L

Executive summary:

A study on chronic toxicity to aquatic invertebrates (Weyers, 2007) was conducted. No significant influence of the test item on the reproduction rate was observed up to a concentration of 0.032 mg/L. A significant inhibition of the reproduction occurred at a concentration of 1.0 mg/L. For that reason, the NOEC and LOEC for reproduction are set at 0.32 mg/L and 1.0 mg/L. The effect concentrations are based on the nominal concentrations since the recovery at concentrations relevant for NOEC derivation was > 80%.

Since no daphnids died after 21 days, the NOEC and LOEC for mortality were determined to be ≥ 1.0 mg/L and > 1.0 mg/L, respectively.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Refer to analogue justification document provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other:

Remarks:

source, CAS 59-50-7, key rel 2, Weyers 2007

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other:

Remarks:

source, CAS 59-50-7, key rel 2, Weyers 2007

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other:

Remarks:

source, CAS 59-50-7, key rel 2, Weyers 2007

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other:

Remarks:

source, CAS 59-50-7, key rel 2, Weyers 2007

Description of key information

NOEC (21 d) = 0.32 mg/L (nominal, Daphnia magna), read-across

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.32 mg/L

Additional information

No study investigating the toxicity ofsodium p-chloro-m-cresolate (CAS 15733-22-9) to long-term daphnia is available. Therefore, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read-across to the source substance(p-chloro-m-cresol, CAS 59-50-7) which is thethe main transformation product of the target substancesodium p-chloro-m-cresolate (CAS 15733-22-9) is applied.

The source substance p-chloro-m-cresolis the common compound in this analogue approach and is solely responsible for the (absence of) effects.Thus, the source substance is considered a suitable representative for the evaluation of the toxicity of the target substance to aquatic organisms. The read-across approach is justified in detail within the analogue justification in IUCLID section 13.

One experimental study is available investigating the long-term effects of the source substance p-chloro-m-cresol (CAS 59-50-7) to aquatic invertebrates (Weyers 2007). The test was conducted according to OECD guideline 211. Daphnia magna were exposed in a semi-static test system for 21 days to nominal concentrations of 0.01, 0.032, 0.1 and 1 mg/L. Recovery rates ranged from 91.5 to 100.6% of the nominal values in the freshly prepared media and from 59.5 to 96.3% in the aged media. Results were based on nominal concentrations since recovery rates in the NOEC and concentrations above were > 80%. Only in the lowest tested concentration, which is below the NOEC and which can therefore be considered not relevant to the overall study result, recoveries below 80% were found. The mortality of adults and the number of neonates was observed three times per week at the renewals of the test media. The NOEC (21 d) based on reproduction was 0.32 mg/L. Since no daphnids died after 21 days, the NOEC and LOEC for mortality were determined to be ≥ 1.0 mg/L and > 1.0 mg/L, respectively.

 Based on the available results from a structurally similar source substance (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which is the main transformation product of the target substance and is characterized by a similar ecotoxicological profile and comparable structure, it can be concluded thatsodium p-chloro-m-cresolatehas effects in the same range as the target substance.