Long-Exposure, Time-Integrated Sampler for Groundwater or the Like

摘要

A system, device, and method quantitatively measure average concentrations of target constituents (e.g., volatile organic compounds (VOCs)) in an ambient fluid (e.g., groundwater, surface water, air, etc.) over an extended period of time. The system uses a passive device having an outer equilibration chamber and an inner kinetic sampler. The device is placed in an ambient fluid for a specified period of time, wherein the target constituent(s) rapidly diffuse through a high-permeability membrane into the fluid-filled equilibration chamber. From there, the target constituents are taken up by an uptake rate the kinetic sampler that is configured to be less than an equilibration rate of the equilibration chamber.

主权项

1. A passive sampling device for measuring one or more concentrations of one or more target constituents in an ambient fluid over a deployment period, the device comprising:
an equilibration chamber having a first inlet; a first membrane of a first permeability disposed at the first inlet and defining an equilibration rate, the equilibration rate controlling equilibration of the one or more target constituents between the ambient fluid and the equilibration chamber; and at least one kinetic sampler in fluid communication with the equilibration chamber, each of the at least one kinetic samplers having an uptake rate for the one or more target constituents, the uptake rate being less than the equilibration rate of the first membrane and maintaining the equilibration between the equilibration chamber and the ambient fluid.