Grab Sampling Collect water, transport to lab, extract, preconcentrate, analyze Offers “accepted” approach and time-point data, but has disadvantages • “Snapshot” in time • No information on chronic exposure or bioavailability • Large amount of water and solvent needed • Often has insufficient sensitivity
Grab Sampling. Collect water, transport to lab, extract, preconcentrate, analyze Offers “ accepted ” approach and time-point data, but has disadvantages “ Snapshot ” in time No information on chronic exposure or bioavailability Large amount of water and solvent needed - PowerPoint PPT Presentation
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Grab SamplingCollect water, transport to lab, extract, preconcentrate, analyze
Offers “accepted” approach and time-point data, but has disadvantages
• “Snapshot” in time• No information on chronic exposure or bioavailability• Large amount of water and solvent needed• Often has insufficient sensitivity
P: Parent PCB
M: PCB metabolites
KPSW and KMSW: PSD-water partition coefficients of P and M
KPOC and KMOC: oil or other organic carbon sorption coefficients of P and M
BCF: bioconcentration factor
BMF: biomagnification factor
MET: metabolic clearance
KPSD and KOIL
Simplified model of the partitioning processes that control the bioavailability of PCB
Uptake Model
Linear: Log Kow ≥ 4.5
Integrative Approach– Provides estimation of TWA
during a specific exposure period
– Chemical residues from episodic chemical events are retained
– Only occurs in linear phase
– Requires calibration data • Effective Sampling Rate (Rs)
– Rs = N / Cw * t
– Cw = N / Rs * t
– T50 = - ln 0.5 KPSDVPSD / Rs
Overall Goal: Advance design/use of PSDs to be more universal, quantitative, and used in site/risk assessment
0 2 4 6 8 10
LDPE, POM, PDMSSPMD
PISCESnd-SPME
MESCOTRIMPS
EcoscopeCHEMCATCHER
Solvent-f illed membranesTLC plates
Ceramic dosimeter PDB
TWA-SPMEPOCISuPSD
Superfund Chemical List
logKow
Porous membrane
Absorbent phase
Cap CuO Filter
O-ring
Goal: to develop a universal PSD (uPSD)Goal: to develop a universal PSD (uPSD)
Measuring freely dissolved PCB using POM and SPME
SPME POM PDMS
Polymer and soil-water slurry were allowed to reach equilibrium