Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
no hazard identified

Marine water

Hazard assessment conclusion:
no hazard identified

STP

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

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
0.22 mg/kg sediment dw
Assessment factor:
100
Extrapolation method:
assessment factor

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.022 mg/kg sediment dw
Assessment factor:
1 000
Extrapolation method:
assessment factor

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Conclusion on classification

MBTS is classified according to the regulation (EC) No 1272/2008 as "very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment" in the hazard category aquatic acute 1 (hazard statement: H400) and aquatic chronic 1 (hazard statement: H410), respectively. This classification however is considered as over conservative according to up-to-date assessment as following:

- Some old studies, supporting the classification of MBTS as aquatic acute 1 (H400) and aquatic chronic 1 (H410) according to GHS (Regulation EC 1272/2008), are judged as invalid according to current regulatory requirement. For example, Monsanto (1979) reported an EC50 to algae of 0.7 mg/l based on cell number but not growth rate, and no exponential growth can be concluded for control experiment; and hence information in this study is insufficient for assessment.

- No acute or chronic toxicity of MBTS to three taxonomic groups of three trophic levels was observed up to its water solubility (i.e. 0.05 mg/L) in the reliable studies.

- MBTS is not readily biodegradable with 0% degradation observed in 28 days (Bayer AG, 1988).

However, the original classification is maintained as self-classification; and hence MBTS shall be classified as aquatic acute 1 (H400) and aquatic chronic 1 (H410) according to GHS (Regulation EC 1272/2008). The appropriate multiplying factors are 1 for acute and chronic toxicity.