Multi-Walled Carbon Nanotubes (MWCNT), synthetic graphite in tubular shape

Distribution modelling

Administrative data

Endpoint:

distribution modelling

Adequacy of study:

other information

Reliability:

other: PNEC deviation: not reliable PEC calculation model well described but not fully reproducible.

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study reports "risk quotients" (PEC/PNEC) for carbon nanotubes. Although the PNECs have been compiled from the literature but the authors state a "low accuracy" of the data. Furthermore the PNECs are based on data for carbon nanotubes which are not covered by this registration as the materials do not have the form as described in section 4.5 of the IUCLID. Thus, the PNECs reported by the authors shall not be used within this registration which means that also the PEC/PNEC ratios calculated shall not be used. However, the estimation of the PECs can - at least to some extent - be used to assess the distribution of MWCNT in the environment. The simulation model is based on scientific principles. The basic data used for the simulation model are well described. However, for the calculation of the PECs, production volumes have been used as most relevant input parameters for the model, but the basis for these productions data was not presented. Due to the uncertainty of the production volumes, the absulte PEC results should be used with care. Nevertheless, the model gives a clear indication in which compartments and to what percentage (air, landfill, soil, surface water, sediment) carbon nanotubes can be expected.

Data source

Reference

Reference Type:

publication

Title:

Modeled environmental concenetrations of engineered naomaterials (TiO2, ZnO, Ag, CNT, Fullereness) of different regions

Author:

Gottschalk F, Sonderer T, Scholz RW, Nowack B

Year:

2009

Bibliographic source:

Environ. Sci. Technol. 2009 43, 9216-9222

Materials and methods

Model:

other: "Probabilistic material flow modeling for assessing the environmental exposure to compounds" according to the method cited in: Gottschalk, F.; Scholz, R. W.; Nowack, B. Probabilistic material flow modeling for assessing the environmental exposure to compo

Calculation programme:

In this study, predicted environmental concentrations (PEC) were calculated based on a probabilistic material flow analysis from a life-cycle perspective of ENM containing products. The environmental concentrations were calculated as probabilistic density functions and were compared to data from ecotoxicological studies. The material flow of ENMs for the United States, Europe and Switzerland were examined.

Release year:

2 008

Media:

other: water, air, soil, sediment, and groundwater

Test material

Test material information

Constituent 1

Reference substance name:

Carbon Nanotubes

IUPAC Name:

Carbon Nanotubes

Details on test material:

Test material identity does not meet the form as described in section 4.5 of the IUCLID dossier and/or it cannot be proved beyond reasonable doubtthat the test material identity meets the form as described in section 4.5 of the IUCLID dossier.

Results and discussion

Any other information on results incl. tables

Please look at "attached background material" for more details on results

Applicant's summary and conclusion

Executive summary:

For Carbon Nanotubes (CNT), the most prominent flows for service life were - starting form production, manufacturing, and consumption (PMC) - landfill and waste incineration. Only minor amounts reach the environment via the direct air pathway and via waste water and sewage treatment plant. Calculations performed for Europe, US and Switzerland show the same tendency: Concentrations in air were calculated to be <0.01 ng/m3. The yearly increase in concentration in soil and sediment is in the range of 100 ng/kg (soil) and 250 ng/kg (sediment). Concentrations in water were reported to be in the fg/L range.

Model data inidcate that the main pathway of CNTs to the environment is via STPs. The main part is expected in sewage sludge, and therefore also sludge treated soil is affected. Discharges of CNTs via STP effluents will result in small portions parts in suface water. CNTs are expected to mainly sediment from surface water. The air compartment is not of importance for CNTs.