Environmental Engineering Reference
In-Depth Information
(Garrigós et al., 2004). Recent studies (Borrelli et al., 2005) on PVC, for
instance, the residual VC values of 2-5 ppb for food packaging, well below
the acceptable levels (by the FDA). Residual monomer is more common in
thermoset plastics compared to common thermoplastics. The most studied
system for residual monomer is dental acrylic resin that is UV-cured
in situ
on the tooth with inevitable monomer residue left over in the buccal cavity
(Kawahara et al., 2004; Lung and Darvell, 2005).
The significance of residual monomers depends not only on their levels in
the plastic resin but also on how readily they leach out and their toxicity.
A hazard rating for monomers based on their modes of toxicity has been
developed as shown in
Table 8.6
(Lithner et al., 2011). However, the risk
from residual monomer toxicity is ultimately the product of its
hazardousness and the likelihood of human exposure to the leached
monomer via ingestion or transdermal delivery.
