Environmental Engineering Reference
In-Depth Information
surfactants. About 10% of it is used in manufacturing phosphite
antioxidants (tris(4-nonyl-phenyl) phosphite used in rubber and plastics
compounds. The stabilizers and plasticizers based on NP are also used in
plastics intended for food-contact applications. They are not highly
persistent chemicals and once discharged into the environment, APEs
rapidly hydrolyze into alkylphenols that are subsequently slowly
biodegraded by microorganisms. The USEPA criteria concentrations for
freshwater NP exposure is CMC = 28 acute-µg/l and CCC = 6.6 chronic-µg/
l:aquatic community might be exposed to >CMC concentration only briefly
saltwater are 7.0 µg/l 1.7 µg/l.
Nonylphenols(NP)areusedasstabilizersorplasticizersinplasticsandhave
been reported to migrate from packaging into food (Guenther et al., 2002).
The levels in lipid-rich foods such as butter or sausage were found to carry
13-14µg/kgofNP.Notsurprisingly,itisalsofoundinhumanadiposetissue
(Lopez-Espinosa et al., 2009) but at a lower level of 57 ng/g. Given the high
volume use of NPEs in detergents, migration from plastics or food-contact
packaging is likely to be relatively a minor contributor to the body burden of
this EDC.
Generally, APEs are much less potent EDCs compared to those previously
discussed.
Invitro
bindingaffinityofAPEstothereceptorsismuchlower(4
orders of magnitude smaller) compared to estradiol. No data from human
studies are available on ED effects of APEs.
7.6 EDCs AND PET BOTTLES
Water and carbonated beverage bottles are made predominantly from
poly(ethylene terephthalate) (PET). The polymer is made by condensation
reaction ofethylene glycolwith either terephthalic acid oritsdimethyl ester.
The process in practice includes three steps: prepolymer formation, melt
condensation to increase viscosity, and solid-state polymerization at
180-230°C to yield a resin with an average molecular weight that is high
