Concrete of honeycomb cells of the bee by hexane extraction

Surface tension

Administrative data

Endpoint:

surface tension

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because based on structure, surface activity is not expected or cannot be predicted

the study does not need to be conducted because surface activity is not a desired property of the material

the study does not need to be conducted because water solubility is below 1 mg/L at 20°C

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
In accordance with column 2 of REACh Annex VII, the study needs only to be conducted if based on structure, surface activity is expected or can be predicted.
The present substance is not intended to be used as a surfactant (i.e. not a desired property), and major constituents (esters and hydrocarbons) do not contain groups (such as distinct polar and non-polar parts) indicating that it will have surface-active properties in solution. Therefore, the study is deemed unnecessary.
Moreover, the target constituents have a water solubility << 1 mg/L (at 25°C), which supports that the test does not need to be conducted.

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

The registered UVCB substance as a whole is considered to have very low water solubility (<< 1 mg/L), based on representative constituents of the major fraction, having solubility in the range 4.7x10-11 to 5.1x10-7 mg/L at 25°C (calculated values).

Considering the registered substance is an UVCB, experimental testing was considered not feasible, due to limited identification of the composition, and analytical issues expected.

Therefore, a constituent-based, Weigh-of-Evidence approach, was prefered.

Two constituents, of a different chemical family, were targeted, as representative.

For the very major, non-volatile, fraction, direct identification was not achieved, due to technical difficulties. The starting material, beeswax is a complex mixture of saturated and unsaturated linear and complex esters (27 to 40% monoesters, 9 to 23 % hydroxymonoesters, 7 to 16% diesters, 3.9% hydroxydiesters), 11 to 28% hydrocarbons, 1 to 18% saturated, unbranched free fatty acids, 4 to 8% of other substances and < 0.3% free fatty alcohols (EFSA Journal (2007) 615, 1-28). The registered substance Concrete of honeycomb cells of the bee by hexane extraction is anticipated to contain selectively extracted constituents. Hexane being a non-polar solvent, non-hydroxy esters and hydrocarbons are supposed to be predominant in the concrete. Based on the same data source, oleyl palmitate and heptacosane were selected, as major component in their family. No published data was available; predictions were calculated with both EpiSuite models, and found very low: 4.7x10-11 and 5.1x10-7 mg/L for the ester, 2.8x10-9 and 3.8x10-7 mg/L for the C27 alkane.

No data is presented for the constituents of the volatile phase, as their amount is considered negligible with regard to the assessement of the substance as a whole. Moreover, the identified constituents are similarly alkanes and alkenes, so anticipated to be of very low solubility too.

No single key value was derived for the UVCB substance, result expressed as a range was prefered, having more scientific sense.