tubings leach organic constituents under either

cant losses of two VOCs from a test solution that

static or dynamic conditions. This is especially

was pumped through PTFE tubing but did not

true for flexible tubings such as PVC and various

quantify what those losses were. Only one study

(Devlin 1987) has addressed what happens to

types of rubber (e.g., black latex, silicone) (Cur-

analyte concentrations when the test solution is

ran and Tomson 1983, Barcelona et al. 1985). One

pumped through tubing for an extended period

reason some flexible products tend to leach or-

of time, i.e., whether equilibration occurs. Devlin

ganic constituents is that they contain large per-

(1987) reported that representative samples

centages of plasticizers. For example, flexible

could be obtained through 100-ft sections of PE

PVC contains 3050% plasticizers (by weight)

tubing after first flushing the tubing for 510

(Junk et al. 1974, Aller et al. 1989), while rigid

min, and that the equilibration time depended

PVC contains less than 0.01% (Barcelona et al.

upon the length of the tubing and the pumping

1984). In contrast, PTFE and other fluoropoly-

rate. However, Devlin did not provide any data

mers have been shown not to leach any organic

that showed this.

constituents (Junk et al. 1974, Curran and Tom-

Therefore, while we know that concentrations

son 1983, Barcelona et al. 1985). These materials

of some organic analytes can be affected when

do not contain plasticizers and generally do not

contaminated water is pumped through some

contain many additives.

tubings, we do not know the full extent of this

We (Parker and Ranney 1996) evaluated twen-

effect. Other unanswered questions include 1)

ty tubings for evidence of leaching after 24 and