Monitoring of Airborne and Waterborne Toxic Organic Contaminants by Use of Semipermeable Membrane Devices (SPMDs)

D.A. Alvarez, J.D. Petty, J.N. Huckins, W.L. Cranor, J.A. Lebo, R.C. Clark, C.E. Orazio

U.S. Geological Survey, Columbia Environmental Research Center, Columbia, MO

G.L. Robertson

U.S. EPA/National Exposure Research Lab, Las Vegas, NV

R.E. Stewart

Virginia Department of Environmental Quality, Richmond, VA

H.F. Prest

Agilent Technologies, Palo Alto, CAU.S. Department of the InteriorU.S. Geological Survey

Semipermeable Membrane Devices (SPMDs)

The SPMD, developed by scientists at the USGS-CERC, is the subject of two U.S. Government patents and is commercially available from Environmental Sampling Technologies, St. Joseph, MO.

The SPMD was specifically designed to sequester hydrophobic (I.e., lipophilic) chemicals from water and air.

It is an abiotic mimetic of the bioconcentration process occurring in organisms exposed to lipophilic chemicals.

SPMDs have been used worldwide to monitor the presence and potential impacts of lipophilic chemicals in a wide array of ecosystems.

Semipermeable Membrane Devices (SPMDs)Membrane

Exploded view of

membrane-lipid sandwich

The lipid containing semipermeable membrane device (SPMD) and a typical deployment apparatus.

Interior

Interior

MembranePore Size< 10

Lipid(Triolein)

ContaminantMolecule

SPMD

Deployment Rackwith SPMD

Protective Shroud

Semipermeable Membrane Devices (SPMDs)

Sampling/Uptake –

•passively samples chemical residues (log Kow>3) from the vapor or dissolved phase under nearly all environmental conditions.

•Integrative sampling (I.e., linear uptake) exists for most exposure scenarios. Models have been derived for all three phases of SPMD uptake (linear, curvilinear, and equilibrium).

•Integrative sampling allows for detection of episodic contaminants releases and is reflective of a time weighted average (TWA) or cumulative dose of lipophilic chemicals.

Permeability/Performance Reference Compounds (PRCs)

• analytically non-interfering organic compounds, such as perdeuterated phenanthrene, with moderate to high fugacity from SPMDs that are added to the lipid prior to deployment.

• Determination of PRC losses allows for adjustment of calibration data to more accurately represent the exposure conditions.

• Corrects for a wide range of environmental conditions (temperature, facial velocity of air/water, biofouling, etc.) to increase the accuracy of ambient concentration estimates.

Chemical Analysis

Instrumental Chemical Analysis

TransportSealedin can

DialyticRecovery

Dialysate

Enrichmentand

Fractionation

Exterior Cleaning

ExposedSPMD

Bioassays and Toxicity Testing

Dialysate

In vitro toxicity testing

Acute Toxicity &Genotoxicity

Solubilize

ExposedSPMD

DialyticRecovery

Transport

Sealed in can

Exterior Cleaning

Semipermeable Membrane Devices (SPMDs)

Ruggedness –

•Capable of surviving harsh environmental conditions

Quality Control –

•Level of QC incorporated is dependent on project goals

•Addresses construction, deployment, retrieval, storage, processing, and analysis

•Provide information on sample integrity and background interferences associated with the entire sampling and analytical process

Reproducibility Between Replicate SPMDs

Unpublished Data

Variation between SPMD replicates is generally <20%.

Rep. 1 Rep. 2 Rep. 3 Mean ± C.V.

Fluoranthene

1360 1450 1400 1400 ± 3.2%

Pyrene 1130 1220 1180 1180 ± 3.8%

Chlorpyrifos

5.65 5.35 5.70 5.57 ± 3.4%

Diazinon 6.41 5.93 6.34 6.23 ± 4.2%

t-Chlordane

4.11 4.15 3.89 4.05 ± 3.5%

o,p’-DDT 1.29 1.56 1.13 1.33 ± 16%

p,p’-DDE 9.03 7.94 8.46 8.48 ± 6.4%

p,p’-DDD 8.89 8.93 8.18 8.67 ± 4.9%

Total PCBs

47.9 39.1 44.4 43.8 ± 10%

Analyte concentrations reported as ng/g SPMD

Data from SPMD sampling in the Elizabeth River, Virginia

PAH and PCB Sampling in Antarctica

SPMDs were deployed for 50 days at 5 sites at McMurdo Station in Winter Quarter’s Bay, Antarctica.

PAH patterns were similar to Diesel Fuel Arctic profiles. Water concentrations of PAHs were estimated up to 1.5 µg/L.

PCBs were present at levels up to 370 ng/SPMD. Patterns were similar to Aroclors 1254 and 1260.

Comparisons To Biomonitoring Organisms

• SPMDs sample only the bioavailable dissolved phase, uptake by organisms occurs via respiration (dissolved phase) and feeding (dissolved and suspended)

• Reproducible with very low background

• Not affected by most water quality parameters or contamination.

• Organisms undergo rapid depuration of gut contents and potential biotransformation and excretion of metabolites

For some environmental contamination scenarios, the use of SPMDs and organisms are complementary.

Water(ng L-1)

Air(pg m-3)

HCB 49 260

-BHC 0.89 860

-BHC 0.21 530

o,p’-DDT ND 340

p,p’-DDT 29 460

p,p’-DDE 33 6300

cis-Chlordane 1.9 460

trans-Chlordane

6.8 420

trans-Nonachlor

4.6 420

Passive Sampling of Water and Coastal Air via SPMDs

Prest, H.F.; Jacobson, L.A.; Huckins, J.N. Chemosphere 1995, 30, 1351-1361.

A 28 day exposure of SPMDs was performed at Younger Lagoon near Santa Cruz, CA.

SPMD uptake is phenomenologicially similar for both air and water allowing estimation of contaminant concentrations using established models.

PCBsHiVol

(pg m-3)SPMD

(pg m-3)

Congener 28 18 12

Congener 52 6.7 8.0

Congener 101

4.2 4.3

Congener 118

1.9 1.6

Congener 138

2.1 1.4

Congener 153

3.1 2.0

Congener 180

0.7 0.5

Total PCBs 93 92

Comparison of Active HiVol Samplers and SPMDs for Airborne PCBs

Ockenden, W.A.; Prest, H.F.; Thomas, G.O.; Sweetman, A.; Jones, K.C. Environ. Sci. Technol. 1998, 32, 1538-1543.

A two month study comparing active HiVol samplers to passive SPMDs was performed by scientists from the Lancaster University in the U.K.

Time required to reach equilibrium between atmospheric and SPMD associated PCBs was estimated to be at least 2.4 years, thereby allowing extended deployments for the determination of TWA concentrations of PCBs.

Air Sampling along the U.S./Mexico border

SPMDs were deployed at 57 sites within residential areas along the border between Arizona and Mexico as part of an integrated assessment of selected airborne organic contaminants.

Analysis of the SPMDs focused on residues of PAHs, OCs, PCBs, and selected current use pesticides (diazinon, chlorpyrifos, endosulfan, permethrin, and trifluralin).

In the three cases where SPMDs were deployed inside and outside of the same house, observed levels of contaminants were generally elevated by a factor of 4 or greater within the house.

Site 2 Site 43 Site 46

Total PAHs 590 3,200 960

Total PCBs 23 16 12

Chlordanes 1.4 3.7 1.5

Endosulfans 1.7 1.4 1.0

Diazinon 240 130 7.6

Chlorpyrifos 650 390 0.4

Permethrins 10 0.21 1.1

o,p’-DDT 33 0.50 0.95

o,p’-DDE 6.0 0.25 0.18

o,p’-DDD 1.2 <MDL <MDL

p,p’-DDT 28 0.44 0.88

p,p’-DDE 4.0 0.29 0.40

p,p’-DDD 2.7 <MDL <MDL

Az Air Estimated Airborne Concentrations (ng/m3)

Conclusions

SPMDs provide a means of estimating TWA concentrations of lipophilic airborne and waterborne chemicals.

Uptake models have been derived to estimate ambient concentrations of selected chemicals based on laboratory calibration data and analyte physicochemical properties.

SPMDs can and have been used under most environmental conditions. PRCs increase the accuracy of analyte concentration estimates by correcting for site specific variability of environmental conditions.

Conclusions

Complex chemical mixtures sequestered by SPMDs can be subjected to various bioassay tests to determine the potential additive or synergistic effects on organism/human health.

SPMDs provide data on a wider range of chemicals from harsher environments than can be achieved by biomonitoring organisms.

Additional information available at:

http://wwwaux.cerc.cr.usgs.gov/SPMD/index.htm

Acknowledgements

M. O’Rourke and S. Rogan

University of Arizona

W.A. Ockenden

Lancaster University, United Kingdom

Partial Funding for SPMD research provided by U.S. EPA, State of Virginia, U.S. Department of Defense, American Petroleum Institute, and the National Science Foundation.