Environmental Engineering Reference
In-Depth Information
K
PS/sw
for Selected Model POPs
Source: Based on Table 1 in Lee et al. (2014).
log
K
ow
a
log
K
PEs/w
log
K
PP/sw
log
K
PS/sw
Chemicals
Phenanthrene
4.52
4.44
4.00
5.39
Fluoranthene
5.20
5.52
4.79
5.91
Anthracene
4.50
4.77
4.29
5.61
Pyrene
5.00
5.57
4.80
5.84
Chrysene
5.86
6.39
5.51
6.63
Benzopyrene
6.35
7.17
6.10
6.92
Dibenzanthracene 6.75
7.87
7.00
7.52
Benzoperylene
6.90
7.61
6.69
7.15
A value of log
K
~ 5 for instance shows that the equilibrium concentration
of the compound in plastic to be 100,000 higher than that in seawater.
Essentially, the presence of plastics at sea tends to clean the water of the
POPs! Despite their low concentration in water, large
K
values suggest very
high equilibrium concentrations of POPs to be reached in micro- and
mesoplastics (Rochman et al., 2013a). At least in theory, plastics debris
can sorb POPs to the saturation point at a highly polluted locale, and on
drifting to a second cleaner-water environment subsequently releases the
contaminant into water (Endo et al., 2013). Contribution to the local
concentrations of POPs in seawater due to this mechanism, however, is
likely not significant because of the minimal mass fraction of carrier
microplastics in sea water.
Rios and Moore (2007) found mesoplastic samples on four Hawaiian, one
Mexican, and five Californian beaches to have high levels of POPs; the
ranges of values reported were ∑ PAH = 39-1200 ng/g, ∑PCB PCB =
27-980 ng/g, and ∑DDT 27-7100 ng/g (cumulative values for all
congeners.) A US beach study (mainly in Californian beaches) (Ogata et al.,
2009) found somewhat lower values: ∑PAH PAH = 32-605 ng/g; ∑PCB =
2-106 ng/g, ∑HCH HCH = 0-0.94 ng/g. Had the samples been collected
from beaches in industrial areas, these concentrations might have been
much higher.
