Isopropyl 4-hydroxybenzoate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

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:

other: Data is from peer reviewed journal.

Justification for type of information:

Data is from peer reviewed journal.

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

Study of 7 days toxicity of isopropylparaben to Ceriodaphnia dubia.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (as cited in study report): Isopropylparaben
- Molecular formula: C10 H12 O3
- Molecular weight: 180.202 g/mol
- Smiles notation: c1(C(OC(C) C)=O)ccc(O)cc1
- InChl : 1S/C10H12O3/c17( 2)1310(12)8359(11)648/h37,11H,12H3
- Substance type: Organic
- Physical state: Solid
- Analytical purity:≥99%

Details on test solutions:

- Chemical name of vehicle (organic solvent, emulsifier or dispersant): breeding water

Test organisms (species):

Ceriodaphnia dubia

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Source: National Institute for Environmental Studies, Tsukuba, Japan
- Age of parental stock (mean and range, SD): mature females (1 week or older)

ACCLIMATION
- Acclimation period: 10 years before the experiment.
- Acclimation conditions (same as test or not): Not same as
Temperature: 26 degree C ±1 degree C
Photoperiod: light and dark cycle was 16:8 h
- Type and amount of food:
Green alga chlorella (Chlorella vulgaris) obtained from Chlorella Industry diluted to 1 X 10(8) cells mL-1 was used as feed at 0.5 mL-1.
0.5 mL-1 YCT (yeast, cerophyll, and trout chow), which was prepared fresh daily in a culture beaker was provided every day.
- Feeding frequency: every day.

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

7 d

Hardness:

87 mL-1 as CaCO3

Test temperature:

25 degree C ± 0.32 degree C

pH:

7.5 to 8.1

Nominal and measured concentrations:

measured concentration as 0.66,1.37, 2.34, 5.05, 9.77 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: glass vessels
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 15ml
- Aeration: No aeration as closed vessel was used.
- Renewal rate of test solution (frequency/flow rate): renewed three times a week.
- No. of vessels per concentration (replicates): 10 replicates
- No. of vessels per control (replicates): 13 neonates

TEST MEDIUM / WATER PARAMETERS
- Conductivity: 26 ±0.95 µS cm-1

TEST CONCENTRATIONS
- Test concentrations: 0.66,1.37, 2.34, 5.05, 9.77 mg/l

Duration:

7 d

Dose descriptor:

LC50

Effect conc.:

1.2 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

2.5 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Number of Offspring

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

6.2 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Time to First Brood

Validity criteria fulfilled:

not specified

Conclusions:

The EC 50 values for long term toxicity to Ceriodaphnia dubia for isopropylparaben (4191-73-5) was determined to be 1.2, 2.5 and 6.2 mg/l based on survival,number of offsprings and Time to First Brood of Ceriodaphnia dubia.

Executive summary:

Long term toxicity tests have been conducted on Ceriodaphnia dubia for 7 days at concentrations of 0.66, 1.37, 2.34, 5.05, 9.77 mg/l. significant differences in the number of offspring (P < 0.01)and time to brood (P < 0.05) were observed at the lowest(0.66 mg/l for iPP) dose groups. Therefore, the EC 50 values for long term toxicity to Ceriodaphnia dubia for isopropylparaben (4191-73-5) was found to be 1.2, 2.5 and 6.2 mg/l based on survival,number of offsprings and Time to First Brood of Ceriodaphnia dubia.

Description of key information

Long term toxicity to aquatic invertebrates

Long term toxicity test have been conducted on Ceriodaphnia dubia by Masanori Terasaki et.al (Environmental toxicology, 12 December 2013)for 7 days at concentrations of 0.66, 1.37, 2.34, 5.05, 9.77 mg/l. Significant differences in the number of offspring (P < 0.01)and time to brood (P < 0.05) were observed at the lowest(0.66 mg/l for iPP) dose groups. Therefore, the EC 50 values for long term toxicity to Ceriodaphnia dubia for isopropylparaben (4191-73-5) was found to be 1.2, 2.5 and 6.2 mg/l based on survival, number of off springs and Time to First Brood of Ceriodaphnia dubia.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.2 mg/L

Additional information

Long term toxicity to aquatic invertebrates was summaries with key and supporting studies for isopropylparaben (4191-73-5) are as follows.

Long term toxicity test have been conducted on Ceriodaphnia dubia by Masanori Terasaki et.al (Environmental toxicology, 12 December 2013)for 7 days at concentrations of 0.66, 1.37, 2.34, 5.05, 9.77 mg/l. Significant differences in the number of offspring (P < 0.01)and time to brood (P < 0.05) were observed at the lowest(0.66 mg/l for iPP) dose groups. Therefore, the EC 50 values for long term toxicity to Ceriodaphnia dubia for isopropylparaben (4191-73-5) was found to be 1.2, 2.5 and 6.2 mg/l based on survival, number of off springs and Time to First Brood of Ceriodaphnia dubia.

Supporting to the above key study by Laura L. Dobbinset.al,(Environmental Toxicology and Chemistry, Vol. 28, No. 12, pp. 2744–2753, 2009) long term toxicity to Daphnia Magna was studied for 10 days at different concentrations. Neonates were used and half of the LC50 determined from the acute test was used as the highest sub chronic exposure concentration; a 0.5 dilution factor was then applied to prepare the remaining concentrations.10 replicates with one Daphnia was applied to each concentration were fed during study. Daily observed for mortality and number of neonates were done. So, on the basis of above result the endpoint for long term toxicity to Daphnia Magna was determined to be LOEC at 2 mg/L concentrations of isopropylparaben (4191-73-5).

Based on the key and supported studies values, the isopropylparaben was considered to be toxic to aquatic invertebrates but as it was readily biodegradable hence, it can be considered to be not classified as per the CLP regulations.