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additional ecotoxicological information
Adequacy of study:
supporting study
2 (reliable with restrictions)

Data source

Reference Type:
Research into the toxicity and effects of polyphosphates on growth of cultures of amoeba, rotifers, tadpoles, and on the succession of organisms in cellulose decomposition.
Wurmbach H, Schneider H, Wagner P, Borchert U and Clasen J
Bibliographic source:
Institute for Farming, Zoology and Bienenkunde of Bonn University.

Materials and methods

Principles of method if other than guideline:
Growth/development and toxicity experimentation on Amoeba Metachaos gratum in CHALKLEY solution with addition of disodium phosphate (DSP) and polyphosphates
Type of study / information:
The following species were investigated:

- Metachaos gratum (amoeba)
- Bufo bufo (amphibian - common toad).
- Xenopus laevis (amphibian - South African claw-toed tree toad)

Test material

Constituent 1
Chemical structure
Reference substance name:
Pentasodium triphosphate
EC Number:
EC Name:
Pentasodium triphosphate
Cas Number:
Molecular formula:
pentasodium triphosphate

Results and discussion

Any other information on results incl. tables

1.      The development of the Amoeba was below the control with a 100-200 mg/l of penta sodium phosphate (STPP), without direct damage visible on the Amoebae. The damages start to appear with a concentration of 300 mg/l of penta sodium phosphate (STPP), but the DL50 was not reached in 24 hours, and the recovery of the culture was evident after 48 h.

2.      The culture of Amoeba is clearly damaged by a 20 mg/l concentration of Graham's salt but further development of the Amoeba happens afterward. The Amoeba culture dies with a concentration of 30 mg/l. The concentration curves indicate the DL50 at 23.5 mg/l.

3.      Increasing the salt concentration of the culture medium by 10 fold reduces significantly the toxicity of Graham's salt, as a 20 m/l Graham's salt concentration then only causes limited initial damage, but the animals then thrive normally. Even the toxicity of a 30 mg/l concentration is significantly reduced as ¼ of the animals survived in one of the two cultures.

4. Graham's salt toxicity is approximately the same as dodecylbenzolsulfonate (TPS note: a surfactant ) for equal concentrations. Diphosphate and triphosphate toxicity is so low that lethal concentration has not occurred in the receiving surface waters, the sewer systems or in sewage works.

5. Toxicity experimentation was conducted on amphibian tadpoles of Xenopus laevis (South African claw-toed tree toad) and Bufo bufo (common toad) in a culture dilution prepared by the team, containing approximately 56 mg/l of well-mixed salts.  The four phosphates - Graham's salt, tetra sodium polyphosphate (TSPP), penta sodium phosphate (STPP) et mono potassium phosphate – were tested with concentrations ranging from 10 to 3000 mg/l on Bufo bufo and Xenopus laevis, the latter has not been tested with concentrations under 200 mg/l as they were not lethal.

6. For Bufo bufo the DL50is reached at is only reached at 450 mg/l for penta sodium phosphate (STPP), at 450 mg/l for tetra sodium polyphosphate and 600 mg/l for Graham's salt. For Xenopus, the results for tetra sodium polyphosphate are slightly lower. The orthophosphates had absolutely no poisoning effects. A lethal effect on some of the animals (Xenopus) is already reached with lower concentration of 450 mg/l for Graham's salt, 300 mg/l for penta sodium phosphate and 250 mg/l for Tetra sodium polyphosphate.

7. It has been noted that at all levels of concentration, the tadpoles that did not die in the first place, completely recovered. A complete and widespread adaptation to very high polyphosphate concentrations was observed. Such high concentration should never occur in sewage works or in receiving surface waters.

8. On the other hand, symptoms of poisoning started with relatively low concentrations, at approximately 1/10 of the lethal dose of polyphosphates, but then disappeared before the concentration reached a lethal level. No poisoning effects were noted with mono potassium phosphate.

9. The poisoning showed itself by an excitation when the product was introduced, followed by a descent to the bottom. Then cramps and uncoordinated movements occurred. Later on, no movements were observed in the dying animals. Except with Graham’s salt on Bufo, the bodies and the connective tissue shrunk. The barbs shrunk in Xenopus. Finally, whitish masses came out of the mouth and the palms dissolved. The Bufo tadpoles lying on the bottom aggregated to form a unique mass. The signs of poisoning are therefore clearly affecting the muscles, nerves and connective tissue.

10. The study of the tissues showed in particular the formation of vacuoles and the swelling of the sarcoplasmic reticulum and also the formation of vacuoles in the white and grey matter of the medula oblongata. The connective tissue had disappeared and in one case, the vitreous humour of the eyes had disappeared and the lens was lying on the retina.  The cartilage was also affected by transformation. The liver cells were thinner and separated from one another. The abdominal cavity contained in one case the content of the intestine and in another some red blood cells.

11. The growth of the tadpoles of Xenopus leaevis was accelerated at the start by orthophosphates and by all of the polyphosphates at a concentration of 10 mg/l. The acceleration of the metamorphosis in all the animals receiving polyphosphates supplement had the result that their body weight was below those of the control group.

12. With higher concentrations of 100 mg/l, all the phosphates, except Graham's salt, had the same action in slowing development and metamorphosis. A few underdeveloped individuals appeared.

13. The excitation at the start of the introduction of the product happened also at low concentration. This excitation disappeared after the animals had a period of adaptation, even with the daily adding of polyphosphate (replacement of 1/3 of the volume) in the culture solution.

14. As In culture experimentation, there is a clear adaptation to polyphosphates. Even with a very high concentration such as 100 mg/l, the orthophosphates and polyphosphates, except for Graham's salt, accelerate growth and development. No disability or abnormality occurred.

15. The testing of decomposition rate showed a decomposition time of 5 days in the dark for penta sodium phosphate and tetra sodium polyphosphate (25 mg/l), accelerated to 4 days when put in bright light. The decomposition time of Graham's salt was 10 days, but only half was decomposed in 20 days in a container with a low population of micro-organisms.

16. Notable changes in the micro-organism population development could not be noted in the cellulose decomposition experiments in which polyphosphates were added.

17. The lethal dose in short-chain polyphosphates is so high that there is no reason to expect possible damage to fauna and flora of the sewage treatment plants or the receiving surface waters. Graham's salt – when included in a certainly inappropriately put together culture solution - is as poisonous as dodezylbenzolsulfonate for amoeba and rotifers, but not for tadpoles.

18. During all experiments, the organism tested showed an obvious strong and rapid adaptation to polyphosphates. As there will be probably a regular input of polyphosphates to the sewage treatment plant and to receiving surface waters, it can be expected that the polyphosphates will be totally non toxic, but on the other hand would boost the development of populations. The practical consequence of this is that the adding of short-chain polyphosphates to washing agents is beneficial as it allows reduced surfactant content. In order to help the adaptation of fauna and flora in the receiving surface waters and sewage treatment plant, it would be positive to construct accumulation basins in order to allow a regular inflow of water and avoid a brutal wave of effluents containing polyphosphates and other substances.

Applicant's summary and conclusion