Risk Assessment of Manufactured Nanomaterials - Environmental and Human Health Impacts of Nanotechnology - page 408

Physico - Chemical Properties

There are many published sources of physico-chemical data, including the Merck
Index and IUPAC Solubility Data Series, that can be considered and used within
risk assessments rather than experimental results. However, the data should be
considered carefully and the state of the substance and range of values must be
evaluated. Included in the physico-chemical properties of a chemical substance is
the determination of the particle size distribution, which would account for nano-
materials and particles (Figure 10.A.2 ).

Toxicological Information

The toxicological information required under REACH can be split further into
eight information groups. While these have been considered separately due to the
ethics of animal work, the experiments must be carefully designed with crossovers
between groups. The groups are:
1 . Skin Irritation/Corrosion. These tests are not necessary if data show the sub-
stance is corrosive/irritating. In vitro tests are required for CSA, whilst in vivo
tests are required for unclassifi ed substances manufactured/imported in amounts
greater than 10 tonnes/year.
2 . Eye Irritation. In vitro tests are not necessary if the substance is considered
irritant/corrosive to skin (and is classifi ed as irritating to the eye). For substances
produced or imported in amounts greater than 10 tonnes/year an in vivo test is
required, unless substance has been determined as irritating.
3 . Skin Sensitisation. In vitro tests are required, and if there is not enough informa-
tion to classify the substance as a skin sensitiser i n vivo tests necessary.
4 . Mutagencity. In vitro and in vivo tests in somatic and germ cells are used to
determine whether the substance is genotoxic in somatic and/or germ cells.
5 . Acute Toxicity. Physico-chemical data previously collected are used to deter-
mine the route of administration of the substance (indicative of the common
route of human exposure). Oral i n vivo acute toxicity tests are required unless
oral exposure is not possible, in which case an inhalation study is necessary.
Further in vivo studies for another (different) exposure route are required for
substances imported or manufactured in amounts greater than 10 tonnes/year.
6 . Reproductive and Developmental Toxicity. If the substance has already been
classed as a genotoxic carcinogen or a germ cell mutagen and the appropriate
risk management measures are in place then further testing is not necessary. A
two-generation reproductive toxicity study is required for substances manufac-
tured or imported in amounts

10 tonnes/year
if the reproductive and developmental toxicity screening study is positive or if
repeated dose toxicity study indicates potential reproductive toxicity.
7 . Repeat Dose Toxicity. These tests are only required if there were indications in
the acute toxicity testing or if the chemical is over the 10 tonnes/year weight
trigger. The tests determine the NOAEL for the substance over 28 days. If the
amount of substance is greater than 100 tonnes/year, or data suggest accumula-
tion, then a sub-chronic or chronic repeated dose study (90 days or 12 months)
is required.

≥ 100 tonnes/year, and for those ≥