Tetrakis(hydroxymethyl)phosphonium chloride, oligomeric reaction products with urea

Endpoint summary

Additional information

The registered substance is always produced and marketed as dissolved in water. As consequence, environment through aquatic organisms is anticipated to be exposed to the mixture of the substance in water rather than direct exposure to the purified substance. Therefore, the testing strategy was designed to take into account this route of exposure. It has thus been concluded that testing the mixture (which exhibits an active content of ca. 65%) was more relevant than testing the substance as such. Several aquatic toxicity tests have been performed on mixture of the registered substance in water which exhibits an active content of ca. 65%. The observed toxicity effects in these tests are expected to be the result of the exposure of aquatic organisms to active content.

 

Short-term toxicity

Short-term toxicity to fish (Oncorhynchus mykiss) tested according to the OECD TG 203 was equal/higher than 100 mg/L (96 h-LC50, measured concentration). Two studies on short-term toxicity to aquatic invertebrates are available. In a first study the test was performed according to the OECD TG 202 and the study reports a 48h-EC50 to Daphnia magna of 16 mg/L (based on nominal concentrations). However, the test material identification was not sufficiently detailed to assess the study as reliable without restrictions and can allow misleading interpretation. Therefore, the short-term toxicity to aquatic invertebrates was repeated in 2010. The study reports a 48h-EC50 of 47 mg/L expressed as active content and a 48h-EC50 of 71 mg/L as test material (both based on nominal concentrations). The algal toxicity was determined in a growth inhibition test with Desmodesmus subspicatus according to OECD TG 201. The 72h-ErC50 and the 72h-ErC10 were determined to 46.947 and 19.158 mg/L (nominal concentration), respectively.

The acute toxicity to aquatic organisms ranges between 10 and 100 mg/L. On an acute basis, fish is the less sensitive species to the registered substance in water. It is concluded that the acute toxicity of the registered substance ranges between 10 and 100 mg/L.

 

Long-term toxicity

Long-term toxicity to aquatic invertebrates was tested in a 21 -day test (Daphnia magna) under semi-static conditions. The test was carried out according to OECD TG 202 (1984), equivalent or similar to OECD TG 211 (2008). The 21d-EC50 (immobilisation) and the 21d-EC50 (reproduction) were determined to 0.057 mg/L and 0.032 mg/L, respectively. The 21d-NOEC (reproduction) was 0.010 mg/L.

This result is retained as representative of the chronic toxicity to aquatic organisms with a no effect concentration of 0.010 mg/L.

On a chronic basis, aquatic invertebrate is the most sensitive trophic level to the registered substance in water

 

Toxicity to microorganisms

Two experimental studies reported results of toxicity of the mixture of the registered substance in water to bacteria from activated sludge. Both studies were performed according to OECD Guideline No 209 (1984). The first study reported a 3h-EC50 of 190 mg/L (nominal concentration). However some inconsistencies were noticed. The second study reported 30 -min EC50 of 260 mg/L (nominal concentration) and a 3-h EC50 of 74 mg/L (nominal concentration).

The toxicity to microorganisms ranges between 10 and 100 mg/L which can affect its potential for biodegradation. The latest result was considered in the risk assessment.