Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

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

Marine water

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

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
1.345 mg/L
Assessment factor:
100
Extrapolation method:
assessment factor

Sediment (freshwater)

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

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.139 mg/kg sediment dw
Extrapolation method:
equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
0.277 mg/kg soil dw
Extrapolation method:
equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

PNECaquatic were derived based on acute test results obtained. As fish is not expected to have a greater sensitivity than the other tested trophic levels, an assessment factor ranging from 100 to 10000 is therefore proposed for deriving the PNECs depending on the type of PNEC.

PNECstp has been derived based upon the Stasinakis, 2001, study which provided a EC50 result of 134.5 mg/l.

PNECsed and soil were derived based on the equilibrium partitioning method.

PNEC oral is not derived as the substance has been demonstrated to be non bioaccumulative.

Conclusion on classification

MBTC is not readily biodegradable.

MBTC is expected to be insoluble.

MBTC is not bioaccumulative (existing bioaccumulation test)

An acute toxicity package is available.

For fish test the analytical methodology used a derivatisation procedure. Therefore it is difficult to attribute the observed toxicity to MBTC or other degradation products. Nevertheless even in this context, the observed toxicity is very low and far above the expected water solubility:Fish--> LC50-96h > 100 mg/L.Therefore no effects observed up to the water solubility limit of MBTC.

For Daphnia and algae, the same procedure was applied but with different results for algae. For Daphnia the situation is the same as for fish. The observed toxicity is very low and far above the expected water solubility: Daphnia --> EC50-48h = 83 mg/L.Therefore no effects observed up to the water solubility limit of MBTC.

For algae, the figures obtained are very low, below 1 mg/L, concentration at which we can expect to have a certain quantity of MBTC solubilized. On the other hand the observed toxicity could also come from degradation products but we do not have sufficient elements for demonstrating this. Nevertheless based on the existing data and considering possible occurrence of MBTC at very low concentration in water, toxicity figures are retained for classification purpose:

Algae --> ErC50 -72h = 0.31 mg/L

According to DSD/DPD classification criteria, MBTC is classified as N - R50/53

According to CLP classification criteria, MBTC is classified Aquatic Acute Category 1 and Aquatic Chronic Category 1 – H410 – M factor = 1