Ultra-Trace PCB Sampling

Why High Volume Sampling?

• Increased demand for detecting lower concentrations of contaminants in waters and sediments

• Need to integrate water samples both spatially and temporally

• Challenge of collecting solid fraction from water column in analytical volume

• Ability to capture discrete timepoints• Field proven– logistically feasible

Traditional High Volume Systems

Infiltrex – Axys technologies

TOPS – USGS

Key Components of HVS systems

• Precision pump – flow and volume monitoring• Solids separator – Glass fiber filter wound or

flat disk• Dissolved phase filter – XAD resin or

Polyurethane foam

Issues with HVS Systems

• Mechanical solids separation with filters biases dissolved phase extraction and provides inconsistent results

• XAD resin is costly and prone to field and lab contamination

• Pump systems -too large and often unreliable• Centrifuge options – too large for most field projects

Polyurethane foam vs. XAD

• PUF material is field proven in air and water studies

• PUF is significantly less expensive• PUF material has better recoveries in

dynamic spike studies (PAHs, PCBs, Dioxins, Pesticides)

• PUF material is less prone to field and lab contamination

XAD Resin vs. PUF media

Dioxin compounds

Rec

over

y

Dynamic Field Spiking of PUF media

Dioxin compounds

Rec

over

y

Vortex Efficiency Study

• Experiment was conducted at CAS laboratories in Kelso, WA • Done to evaluate the efficiency of a Krebs vortex separator to

remove suspended sediment. • Particle standards from 0.1 micron to 180 microns were mixed

in 5 gallon carboys and sampled pre and post vortex separator. • 40 sample sets were completed to evaluate efficiency. • A LISST particle analyzer was used to sample the suspended

sediments pre and post vortex separator. • The LISST particle analyzer measures particles using a laser

and presents both concentration and particle size distribution data.

Test Set-up

LISST 100X

HVS System

Solids Sample

Results – Pre Vortex

Results – Post Vortex

Vortex solids separation

Vortex systems provides consistent separation of solids with minimum disturbance to dissolved phase

The vortex cylinder utilizes pressure from the pump and does not require independent propulsion (eg. centrifuge)

Vortex systems are easily field maintained and cleaned.

Vortex Separator Recovery modeled (%)(Krebs Engineers)

Gravity Consulting HVS systemPR-2900

Picture 1 – Gravity PR-2900 System Overview

Vortex Separator Solids chamber Flat Disk Filter (142 mm) Dissolved Phase Trap (PUF)

Projects using Gravity’s HVS system

• Snake River – NPDES studies• Willamette River – CERCLA project• Port of Longview/Lost Angeles – CERCLA

Department of Energy - multiple nuclear sites• Department of Defense – multiple navy facilities• Upper Columbia River –RCRA study• Passaic River – CERCLA Project• Gulf of Mexico MC252 spill - NRDA

Passaic RiverHeavily industrialized segment of river containing PCBs, dioxins, heavy metals, and other hazardous substances from historical and ongoingsources

Upper Columbia RiverHistoric mining operations associated with heavy metal, PCBs and organic contamination.Study was conducted over 160 miles of river