Dimethyl phthalate

Toxicity to other aquatic organisms

Administrative data

Endpoint:

toxicity to other aquatic vertebrates

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: The GC–MS analyses showed that water and solvent controls contained traces of phthalates. Furthermore, malformation rates for the water control were slightly above the recommended 10%.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2016

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: modification of the FETAX protocol

Version / remarks:

ASTM International. 2004. Standard guide for conducting the frog embryo teratogenesis assay—Xenopus (FETAX). Philadelphia, PA, USA

GLP compliance:

no

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Aquatic vertebrate type (other than fish):

frog

Test organisms (species):

other: Silurana tropicalis

Details on test organisms:

Adult western clawed frogs (Silurana tropicalis) were reared in dechlorinated and aerated water from the Queen’s University Animal Care Facility (Kingston, ON, Canada).

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

The exposures lasted 72 h as opposed to the 96 h suggested in the FETAX protocol, from gastrulae (NF11–12) until the start of feeding (NF46).

Test conditions

Test temperature:

26.0 +/- 1.0 °C

pH:

7.2 - 8.4

Nominal and measured concentrations:

Nominal: 0 mg/L, 0.115 mg/L, 1.15 mg/L, 11.5 mg/L, 38 mg/L, 115 mg/L, and 1150 mg/L,
Measured: 0.03 mg/L, 0.1 mg/L, 1.6 mg/L, 9.1 mg/L, 34.1 mg/L, and 924 mg/L

Details on test conditions:

Embryos were dejellied to facilitate handling by gently swirling for 2 min in 2% w/v L-cysteine solution prepared with the Frog Embryo Teratogenesis Assay Xenopus (FETAX; [20]; pH 8.1) at developmental stages Nieuwkoop and Faber (NF) 9 to NF10.
Each treatment was tested in 4 to 17 replicates of 30 mL of FETAX solution containing 40 to 50 western clawed frog gastrulae (NF11–12) each.
Observation
- Mortality
- Morphology
- Gene expression

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

> 9.1 - < 34.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1.6 - < 9.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

morphology

Applicant's summary and conclusion

Conclusions:

According to the publication the results suggest that phthalate diesters could be harmful to amphibian populations at high concentrations. The lowest observable effect concentrations for DMP and DCHP are 2 to 3 orders of
magnitude greater than the highest reported concentrations of the most studied phthalates found in rivers. Based on the present study, MMP, DMP, and DCHP are therefore not believed to pose a significant hazard to early life stages of western clawed
frog in current environmental settings.