Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

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

Marine water

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

STP

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

Sediment (freshwater)

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

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.031 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:
0.056 mg/kg soil dw
Extrapolation method:
equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

The toxicity of N-butyl-2,2,6,6-tetramethylpiperidin-4-amine (N-butyl TAD) has been assessed for the three standard aquatic trophic levels. For fish, a toxicity test with Danio rerio has been conducted according to EU method C.1 and revealed an effect level >100 mg/L. This result is supported by another study with the orfe, which showed a LC50 of 206 mg/L. In an acute toxicity test with daphnia magna according to EU method 84/449/EC C.2, the EC50 has been determined to 20 mg/L. A second study with Dapnia magna demonstrated a LC50 of 28.1 mg/L, supporting the results of the key study. The toxicity on algae has been determined with the green algae Scenedesmus subspicatus with analytic detection of the test substance. An effect concentration EC50 of 10.1 mg/L and a NOEC of 3.7 mg/L has been determined based on the biomass after 72 h. Based on these data, the algae is the most sensitive organism towards the exposure with N-butyl-TAD.

The effect level LC50 of the test substance to microorganism has been shown to be >100 mg/L after 3 h in a bacteria inhibition test according to guideline 87/302/EEC in compliance to GLP.

The calculation of PNEC is based on the aquatic test results and the assessment factors recommended in the Technical Guidance Document R.10 (ECHA, 2008) have been applied. No studies for sediment-dwelling or soil organisms have been conducted. Therefore, the PNECs for sediment and soil have been derived by using the equilibrium partitioning method according to the guidance document R.10 (ECHA, 2008) as screening value.

Furthermore, as the log Koc is low, N-butyl-TAD is expected to have a low potential for adsorption. Due to the logKow below 3, N-butyl-TAD is not expected to have a potential for bioaccumulation.

PNEC aquatic

The effect level of algae, which represents the most sensitive species when exposed to N-butyl-TAD was used for calculation of the PNEC aqua (freshwater). According to the guidance document R.10 the algae has to be treated as a short-term toxicity value and an assessment factor of 1000 was applied, resulting in a PNEC freshwater of 0.010 mg/L. The same effect level was used for derivation of the PNEC aqua (marine) as no data is available for marine organisms. Here, an assessment factor of 10000 was used, resulting in a PNEC marine water of 0.001 mg/L.

PNEC Intermittent release

The PNEC intermittent releases is based on the lowest endpoint obtained in short-term tests. There are short-term data available for all three trophic levels. The lowest EC50 of the relevant available toxicity data is the effect level (72 h) for algae of 10.1 mg/L. This value was used for the calculation of PNEC for water in the case of intermittent releases. As recommended by ECHA (2008), an assessment factor of 100 is applied to the lowest endpoint.

PNEC STP

The test on respiration inhibition resulted in a EC50 value of > 100 mg/L. In a worst case approach an LC50 =100 mg/L is used to derive the PNEC STP. As the EC50 is used, an assessment factor of 100 is applied, according to the guidance document R.10.

 

PNEC sediment

As no studies for sediment organisms are available, the PNEC sediment was calculated using the equilibrium partitioning method as a screen for assessing the risk to sediment dwelling organisms. The PNECfreshwater sedimentwas calculated according to the equation R.10-2 of the guidance on information requirements and chemical safety assessment R.10:

PNECsediment (freshwater)= (Ksusp-water/RHOsusp)*PNECwater* 1000

PNECsediment (freshwater)= (7.65/1150)*0.0101*1000= 0.0672 (wet weight)

PNECsediment (freshwater)= 0.0672 * 4.6 = 0.3091 mg/kg sediment dw

Ksusp-waterwas calculated to be 7.65 based on the equation R.16-7 of the guidance on information requirements and chemical safety assessment R.16 (v.3.0, Feb. 2016); RHOsusp= 1150 and the PNECwateris indicated above. The conversion factor from wet weight to dry weight is 4.6.

 

The PNEC marine water sediment was derived as described according to equation R.10-3 using the PNEC aqua marine water.

As the PEC/PNEC ratio is below 1 in the chemical safety assessment, is it concluded that testing on sediment dwelling organism is not indicated.

 

PNEC soil

As no studies for soil organisms are available, the PNEC for soil was derived by using the equilibrium partitioning method according to equation R.10-5 of the guidance on information requirements and chemical safety assessment R.10:

PNECsoil= (Ksoil-water/RHOsoil)*PNECwater* 1000

PNECsoil=8.300/1700*0.0101*1000 = 0.0493 (wet weight)

PNECsoil=0.0493*1.133 = 0.0559 mg/kg soil dw

Ksoil-waterwas calculated to be 8.3 based on the equation R.16-7 of the guidance on information requirements and chemical safety assessment R.16; RHOsoil= 1700 and the PNECwateris described above. The conversion factor from wet weight to dry weight is 1.133.

As the ratio of PEC/PNEC for soil does not reach the trigger of >1 in the chemical safety assessment, further testing with soil organisms is not required. Furthermore, the log Kow is below 3 (see point 4.7) and the substance is expected to have a low adsorbing potential.

Conclusion on classification

Only short-term toxicity studies on aquatic organisms are available. Alage represents the most sensitive species when being exposed to N-butyl-2,2,6,6-tetramethylpiperidin-4-amine (N-butyl TAD). The acute effect level for algae is EC50=10.1 mg/ L and has a NOEC of 3.7 mg/L. Furthermore, the test substance is regarded to be not readily biodegradable, as the substance has been found to be biodegradable, but not readily biodegradable. The acute endpoint of the most sensitive species (algae) is in the range between 10 and 100 mg/L. Therefore, the substance should be classified as chronic toxic to aquatic organisms, category 3 (H412) according to Regulation (EC) No. 1272/2008 and, additionally, as acute toxic to the aquatic environment, category 3 (H402) according to UN-GHS (5th edition).