1994). Much of the reason for this difference is
tubings: silicone rubber, linear polyethylene
that the plasticizer content of FPVC ranges from
(which, according to Charrier [1990], is high-den-
30 to 50% by weight (Junk et al. 1974, Aller et al.
sity PE [HDPE]), PP, FPVC, and PTFE. They found
1989), while RPVC contains virtually no plasticiz-
that all but the PTFE leached significant amounts
ers (< 0.01%) (Barcelona et al. 1984).
of organic carbon in 30 minutes. The FPVC and
silicone rubber tubings leached the most.
Leaching studies that tested tubings
Devlin (1987) was unable to detect any constit-
Junk et al. (1974) tested several plastic tubings
uents leaching into water pumped through an
to determine if they leached organic constituents
unspecified type of fluoropolymer (Teflon) tub-
when water was pumped through them. The ma-
ing or PE tubing.
terials they tested included rigid polyethylene
(PE), rigid polypropylene (PP), black latex, and
Leaching studies of polymeric products
six formulations of FPVC tubing. They found that
other than tubing
all the tubings leached constituents even though
Miller (1982) was unable to detect any organic
they had been prerinsed. Leached concentrations
constituents leaching from two rigid materials:
were the highest from a food- and beverage-
low-density PE (LDPE) and PP (purchased direct-
grade FPVC and were much lower (three orders
ly from the plastics manufacturer).
of magnitude) from laboratory-grade FPVC, PP,
In a static study conducted by this laboratory
and PE tubings. They noted that most (5090%) of
(Ranney and Parker 1994), no organic constitu-
ents were detected leaching into water from ei-
the total contamination was due to the leaching of
only a few (46) constituents. Many of the con-
ther PTFE (well casings) or fluorinated ethylene
taminants that leached from the PVC and black
propylene (FEP) (sampling pipe). (These test
latex tubing were identified as plasticizers and
solutions were analyzed using reversed-phase
other additives. However, they were unable to
high-performance liquid chromatography (RP-
HPLC) analyses. In most of the previous studies,
identify the major contaminants that leached
from the PE and PP tubing. They also found that
samples were concentrated and analyzed by gas
the amount of contamination leached from the
chromatography-flame ionization detection [GC-
PVC tubing was related to the linear velocity of
FID], or GC-FID and gas chromatography-mass
the water flowing through the tubing, with more
spectrometry [GC-MS].)
contamination occurring at the higher flow rates.
They suggested that this was due to an erosion
Summary of the leaching studies
mechanism occurring at the polymer/water in-
These studies show that FPVC and rubber tub-
terface at the higher flow rates. They found that
ings leach substantial quantities of organic con-
although an initial flushing of PVC tubing with
stituents, and that leaching tends to be less from
water had a salutary effect in lowering contami-
the more rigid formulation (e.g., PE and PP). The
nant leaching, extensive washing served no use-
fluoropolymers tested (PTFE, FEP) do not appear
ful purpose. They concluded that FPVC tubing
to leach any constituents. For at least one poly-
contained a nearly inexhaustible supply of con-
mer (FPVC), higher flow rates increase leaching,
taminants because of its high concentration of
possibly due to erosion of the polymer matrix.
plasticizers, but that this would not be the case
for PE and PP tubings.
Sorption of organic contaminants
With respect to sorption, again the importance
Curran and Tomson (1983) compared the
of differentiating between flexible products and
leachates from PP, PE, polytetrafluoroethylene
(PTFE, a type of Teflon), and FPVC (Tygon) tub-
rigid products has been demonstrated with PVC.
Gillham and O'Hannesin (1990) found FPVC tub-
ings and RPVC (pipe). They found that PTFE did
not leach any detectable organic contaminants.
ing was much more highly sorptive of organic
Leachate concentrations were highest from the
solutes than RPVC (pipe). As an example, there
FPVC tubing. They noted that the total amount of
was no loss of benzene after one hour in samples
exposed to RPVC, but there was approximately a
contaminants leaching from the PE and PP tub-
55% loss in samples exposed to FPVC tubing.
ings was less than Junk et al. (1974) had observed.
They felt that this may have been because of dif-
Sorption studies that tested tubings
ferences in flow rate, tubing conditioning, or
manufacturing.
A field study by Pearsall and Eckhardt (1987)
documented that concentrations of two volatile
Barcelona et al. (1985) looked at a variety of
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