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Ecotoxicological information

Toxicity to other aquatic organisms

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toxicity to other aquatic vertebrates
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference Type:
Evaluation of Phosphate Toxicity in Cope’s Gray Treefrog (Hyla chrysoscelis) Tadpoles
Earl JE & Whiteman HH
Bibliographic source:
Journal of Herpetology, Vol. 44, No. 2, pp. 201–208

Materials and methods

Test guideline
no guideline available
Principles of method if other than guideline:
To investigate possible phosphate toxicity, Hyla chrysoscelis tadpoles were exposed to concentrations ranging from 0–200 mg/L PO4-P for 15 days.
GLP compliance:
not specified

Test material

Constituent 1
Reference substance name:
sodium phosphate
sodium phosphate
Details on test material:
- Name of test material (as cited in study report): sodium phosphate

Test solutions

Details on test solutions:
Each treatment had 40 replicates with one tadpole per dish as a replicate. Each day, the number of dead tadpoles was assessed. The water was changed every three days to produce a static renewal experiment and water samples were taken from a randomly chosen dish from each treatment at the time of the water change. On days when the water was not changed, 10 ml of the very soft water solution with 0 mg/L PO4-P was added to every dish to compensate for water loss resulting from evaporation. In one randomly chosen dish from each treatment, the temperature to the nearest 0.25uC, pH to 0.01, and dissolved oxygen to 0.01 mg/L, were measured every one to two days using a mercury thermometer, Orion pH meter model 210A, and YSI dissolved oxygen meter model 54A, respectively.

Test organisms

Test organisms (species):
Hyla chrysoscelis
Details on test organisms:
- Common name: Cope's Gray Treefrog
- Strain: Hyla chrysoscelis
- Source: Hyla chrysoscelis eggs were collected on 2 June 2006 from a pond at Hancock Biological Station in Calloway County, Kentucky.
- Age at study initiation (mean and range, SD): The experiment was started three days after hatching, when tadpoles, ranging from stage 23–25
- Feeding during test: yes
- Food type: mixture of ground alfalfa pellets and fish food at a 3 : 1 ratio.
- Amount: no data
- Frequency: ad libitum

Study design

Test type:
Water media type:
Limit test:
Total exposure duration:
15 d
Remarks on exposure duration:
approximately half to three-fourths of the total larval period of H. chrysoscelis under similar laboratory conditions
Post exposure observation period:

Test conditions

10–13 mg CaCO3/L
Test temperature:
Test temperature was measured to the nearest 0.25°C but values are not quoted in literature report.
Dissolved oxygen:
Dissolved oxygen was measured but values are not quoted in literature report.
Not applicable
Nominal and measured concentrations:
0, 1, 10, 100, and 200 mg/L PO4-P as sodium phosphate.
Details on test conditions:
- Test vessel: glass culture dish

Results and discussion

Effect concentrations
Dose descriptor:
Effect conc.:
200 mg/L

Any other information on results incl. tables

Phosphate was not found to be directly toxic to the test species. However, addition of phosphate did result in pH increases which could result in pH-related effects.

Applicant's summary and conclusion

Phosphate was found to have no effect on the survival, growth, or developmental stability of the tadpoles, indicating that phosphate may not be toxic to this species at levels associated with anthropogenic inputs. Phosphate was found to increase the pH of the test water, which, in conjunction with other stressors, may have negative effects within aquatic communities. However, phosphate could also affect anuran tadpoles positively by increasing algal food resources.