Environmental Engineering Reference
In-Depth Information
used in the US. The commercial product contains 97-98% deca-BDE, along
with 0.3-3.0% other PBDEs, mainly nonabromodiphenyl ether. The water
solubility and partition coefficients for these are listed in
Table 7.9
.
BDEs
Congener Degree of Br
substitution
log
K
o/w
Water solubility,
mg/l
Deca-BDE 10
10
0.02-0.03
Octa-BDE 8
5.50-8.90 <0.01
6.86-7.92 4.08 × 10
-03
Hexa-BDE 6
6.64-6.97 9.00 × 10
-07
Penta-BDE 5
Tetra-BDE 4
5.87-6.16 0.07
Though no longer manufactured, the lower-brominated congeners are
widely spread in the environment because of their historic use (Gaylor et
al., 2012; Renner, 2000). PBDEs have been reported from biological tissue,
water, and sediment samples collected from even the most remote
environments such as the Antarctic (Hale et al., 2008). It is widely present
in biota and in human blood, fat tissue, and breast milk (Schecter et al.,
2005). In most environmental compartments as well as in human milk, the
level of BDEs has been on the increase in the past decade.
PBDEs are persistent and toxic compounds that affect the liver and, thyroid,
and cause reproductive/developmental, and neurological damage. Once
released to the environment, PBDEs are photolytically debrominated by
exposure tosunlight and bythe action ofanaerobic bacteria. In HIPS blends
(as in equipment casings), the deca-BDE exposure to sunlight can result in
the formation of polybrominated dibenzofurans (PBDFs) (Kajiwara et al.,
2008) that are also toxic compounds. The deca-BDE has a short residence
time in animals, and ingested material is mostly excreted within 24 h.
PBDEs are usually not used in food-contact applications ruling out their
leaching into packaged food; yet, food and beverage are important routes
of intake, as PBDEs are present in both water and air. However, as with
phthalates, exposure via hard plastic toys can result in high values of intake
approximating 10
−4
mg/kg body weight in children (Chen et al., 2009).
