Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
21.6 µg/L
Assessment factor:
1 000
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
2.16 mg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
2.16 µg/L
Assessment factor:
10 000
Extrapolation method:
assessment factor

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
10 mg/L
Assessment factor:
10
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
80.8 µg/kg sediment dw
Extrapolation method:
equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
8.08 µg/kg sediment dw
Assessment factor:
10 000
Extrapolation method:
assessment factor

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
3.48 µg/kg soil dw
Extrapolation method:
equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
PNEC oral
PNEC value:
66.7 mg/kg food
Assessment factor:
300

Additional information

Valid aquatic short-term toxicity studies with algae (OECD TG 201), Daphnia (OECD TG 202), and fish (OECD TG 203) were being conducted with read across material MPAAU. The fish LC50 is 934.1 mg/L, and the Daphnia EC50 is 350 mg/L. The most sensitive of the three trophic levels is the algae with an EC50(growth) of 43.1 mg/L, which corresponds to an EC50 of 21.6 mg/L for the active substance, i.e. the substance registered MPA*. This value of 21.6 mg/L therefore was used as starting point for the computation of aquatic PNEC values.

In a valid sludge respiration inhibition study (OECD TG 209), the effect of the test item Methyl phosphonic acid 70 % on the respiration of activated sewage sludge micro-organisms gave a 3-hour EC50 value of greater than 1000 mg ai/L. The No Observed Effect Concentration (NOEC) after 3 hours exposure was 100 mg ai/L, which was used for the computation of the PNEC STP.

No studies available for sediment and soil toxicity. The equilibrium-partitioning method is applicable for the computation of PNEC sediment and PNEC soil.

*The data for this critical endpoint is based on a study on MPAAU and so the actual concentration of MPA needs to be determined. MPAAU consists of 1 part MPA and 1 part AU. Using the molecular weight of each substance, the nominal concentration of MPA in the study can be determined and thus the endpoint can be determined accordingly for MPA. Converting a weight/weight concentration of MPAAU into a weight/weight concentration of MPA the molecular weight of MPA has to be divided by the molecular weight of MPAAU. The molecular weight of MPA is 96. The molecular weight of MPA is 198. 96/198 = 0.48. Therefore, the relevant endpoint value for a study on MPAAU can be multiplied by a factor of 0.48 to determine to endpoint value for MPA. The EC50 for algal growth inhibition 43.1 mg/L is for MPAAU and therefore, the EC50 for MPA can be reduced to 21.6 mg/L. 

Conclusion on classification

The L(E)C50 values are based on acute aquatic toxicity studies on MPAAU and so the actual concentration of MPA needs to be determined. MPAAU consists of 1 part MPA and 1 part AU. Using the molecular weight of each substance, the nominal concentration of MPA in the study can be determined and thus the endpoint determined accordingly for MPA. Converting a weight/weight concentration of MPAAU into a weight/weight concentration of MPA the molecular weight of MPA has to be divided by the molecular weight of MPAAU. The molecular weight of MPA is 96. The molecular weight of MPA is 198. 96/198 = 0.48. Therefore, the relevant endpoint value for a study on MPAAU can be multiplied by a factor of 0.48 to determine to endpoint value for MPA.

The EC50 for algal growth inhibition of 43.1 mg/kg bw/day is for MPAAU, and therefore the EC50 for MPA can be reduced to 21.6 mg/L (EC10 = 6.75 mg/L, NOEC = 1.6 mg/L). In the same way the LC50 for fish can be calculated to 467 mg/L, and the EC50 for Daphnia to 175 mg/L.

Acute aquatic toxicity:

No classification applicable according to both the CLP and the DSD Regulation, as all L(E)C50 values from aquatic short term toxicity studies revealed results well above the trigger value for acute aquatic toxicity classification of 1.0 mg/L.

CLP - Chronic aquatic toxicity:

According to the 2nd Amendment of the CLP Regulation, for chronic aquatic toxicity classification data from long-term studies are preferred over data from acute aquatic studies. The algal growth inhibition study with read across substance MPAAU is the only available long-term study on aquatic toxicity. This study revealed (for growth rate) a 72h-EC10 of 6.75 mg/L, and a 72h-NOEC value of 1.6 mg/L. Based on this NOEC, which is above the classification trigger value of 1.0 mg/L, there results no classification for chronic aquatic toxicity. As for fish and Daphnia no data from long-term studies are available, the aquatic chronic toxicity classification for these two species has to be based on the respective L(E)C50 values. With L(E)C50 values for both fish and Daphnia above the trigger level of 100 mg/L, these data also do not trigger chronic aquatic toxicity classification under CLP.