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Administrative data

Description of key information

No repeated dose toxicity study with zinc dipropionate is available, thus the repeated dose toxicity will be addressed with existing data on its two individual moieties zinc and propionate. The hazard assessment is based on the most toxic moiety, i.e. the zinc cation.

Please refer to the section for the respective assessment entity for data on the moieties.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

The zinc cation is selected as most toxic moiety for DNEL derivation, as in studies in which humans were supplemented with zinc (as zinc gluconate), at a LOAEL of 2.5 mg Zn/kg bw/day (150mg/day) decreased ESOD activity and effects are seen as a result of copper imbalance. The NOAEL= 0.83 mg/kg bw/day (50mg/day). Whereas the effects of propionic acid in repeated dose toxicity studies are limited to local site-of-contact effects triggered by the caustic properties of the acid. Systemic effects of propionic acid are lacking although doses far exceeding the limit dose of the relevant guidelines were administered. The local site-of-contact effects of propionic acid are considered not relevant for zinc dipropionate: (1) Because the irritant activity of this salt is much less pronounced than the irritant activity of the acid. Propionic acid is classified in skin corrosion category 1B, which indicates that already a single exposure time of less than 1 h  may  produces destruction of (skin) tissue. Whereas zinc dipropionate is not classified for skin irritating / skin corrosive actiivity as in an in vivo study according to OECD guideline 404 it induced neither edema nor oedema. However zinc dipropionate is classified for eye effects category 1 based on an in vitro test result. (2) If the dose descriptor for repeated dose effects of the acid (733 mg/kg bw/d) is read across to zinc propionate, the recalculated value for zinc dipropionate would exceed the guidelines limit dose. And also for this, it can be concluded that zinc dipropionate does not pose a repeated dose toxicity hazard based on the propionate moiety.

However, also zinc is not expected to induce really adverse effects in humans. Zinc is essential for human growth and development, neurological functions and immunocompetence. The main clinical manifestations of zinc deficiency are growth retardation, delay in sexual maturation or increased susceptibility to infections (SCF, 2003). Health specialists recommend supplementing the diet with zinc in case human diet is zinc deficient. The maximum allowable daily intake has been established to be 50 mg zinc per day.There is no experimental sufficient evidence for specific target organ toxicity based on the reversibility of the ‘adverse’ effects demonstrated.

SCF 2003: Scientific Committee on Food, 2003. Opinion of the Scientific Committee on Food on the tolerable upper intake level of zinc (expressed on 5 March 2003). European Commission, Health and Consumer Protection Directorate-General, Directorate C - Scientific Opinions, C2 - Management of scientific committees; scientific co-operation and networks. [Accessed 2009 December 4]. Available from: https://ec.europa.eu/food/sites/food/files/safety/docs/sci-com_scf_out177_en.pdf

Justification for classification or non-classification

As the two moieties of zinc dipropionate do not induce adverse effects leading to a STOT RE classification, zinc dipropionate in all probability has also no potential for systemic toxicity leading to a classification.

According to the criteria of REGULATION (EC) No 1272/2008 and its subsequent adaptions, zinc dipropionate does not have to be classified and has no obligatory labelling requirement for Specific target organ toxicity arising from repeated exposure (STOT-RE).