Applicability of SPMDs

Although SPMDs concentrate a very wide range of hydrophobic organic compounds, they are not suitable for all environmental contaminants. Table 2.1 lists chemicals classes or selected compounds shown to concentrate in SPMDs, but is not all inclusive. 

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Similar to the previous section, we discuss only selected works to highlight the development of SPMDs. Also, we include some discussion of several unpublished pilot smdies (Huckins, 1989) that influenced our early development of SPMDs. These pilot studies were directed solely toward sampling the aqueous phase. The flrst application of SPMDs for sampling organic vapors did not occur until several years later (Petty et al., 1993). To our knowledge, only SPMDs, PESs and SPMEs are being applied in both air and water, because the use of many passive samplers is limited to a specific medium and exposure scenario. 

Figure 2.2 Various applications of SPMDs reported in the literature.

Successful applications of the SPMD technology under a wide variety of field conditions have been demonstrated by a number of researchers (see Appendix B or CERC, 2004). The common threads among successful applications of SPMDs are a basic understanding of potential sources of sample contamination and losses, the functional aspects of the SPMD technique, and the adherence to sound sampling approaches and good laboratory practices. 

When using purified triolein, most samples are amenable to bioassay after di-alytic enrichment. For example, Microtox bioassay of dialysates of SPMDs shows that the SPMDs made with the purified triolein have lower acute toxicities than dialysates from SPMDs made from unpurified triolein (Johnson, 2001). Finally, examination of the dialysates using the yeast estrogen screen (YES) assay (Routledge and Sumpter, 1996) demonstrated that the purification procedure removes all background estrogenic activity (Lebo et ah, 2004). Use of triolein purified by this process expands the potential applicability of SPMD sample extracts to include numerous bioassay procedures (see Chapter 6) and GC-MS as a standard analysis technique. 

Caslavsk, J. Zdrahal, Z. Vytopilova, M. 2000, Application of SPMDs for PAH sampling in the DEZA chemical factory. Polycyclic Aromat. Compd.W 123-141. 

Zhang, J. and Zhang, Y. 2001, Development and application of SPMD technology to environmental research. Mar. Environ. Sci. 20 67-74. 

In subsequent chapters, we provide an overview of SPMD fundamentals and applications (Chapter 2) the theory and modeling which includes the extrapolation of SPMD concentrations to ambient environmental concentrations (Chapter 3) study considerations such as the necessary precautions and procedures during SPMD transport, deployment, and retrieval (Chapter 4) the analytical chemistry and associated quality control for the analysis of SPMD dialysates or extracts (Chapter 5) a survey and brief description of bioassays-biomarkers used to screen the toxicity of SPMD environmental extracts (Chapter 6) discussions on how HOC concentrations in SPMDs may or may not relate to similarly exposed biomonitoring organisms (Chapter 7) and selected examples of environmental studies using SPMDs (Chapter 8). In addition, two appendices are included which provide... 

Petty, J.D. and Orazio, C.E. 1996, Application of Semipermeable Membrane Devices (SPMDs) Ay Passive Monitors of the Environment of Antarctica. USGS, Midwest Science Center, Columbia, MO Unpublished report to National Science Foundation Washington, DC. 

No large variation in sampling rates is observed among the different studies, despite differences in exposure conditions, such as wind speeds, temperature, and SPMD mounting layout. It should be noted, however, that the effect of temperature is partially accounted for by our use of temperature-corrected log A oa values. An example of the application of Eq. 3.68 for calculating atmospheric concentrations is given in Box 3.3. 

Petty, J.D. Huckins, J.N. Zajicek, J.L. 1993, Application of semipermeable membrane devices (SPMDs) as passive air samplers. Chemosphere 27 1609-1624. 

The application of appropriate Quality Control (QC) procedures or criteria is a mandatory consideration in the deployment and analysis of SPMDs (e.g.. Petty et al., 2000a). Similar to any performance-based methodology or approach. 

Herein, we describe the basic QC samples and parameters related to the performance of SPMD studies, and elucidate their role in conducting smdies. Also, a general overview of SPMD analytical procedures and data applicability are given. 

The use of SPMDs to sequester hydrophobic contaminants for incorporation into bioindicator test-based screening is increasing in both frequency of application and in the array of modes of action. Eor example, as a focused part of a broader... 

Zajicek, J.L. Tillitt, D.E. Huckins, J.N. Petty, J.D. Potts, M.E. Nardone, D.A. 1996, Application of Enzyme-Linked Immunosorbent Assay (ELISA) for Measurement of Polychlorinated Biphenyls (PCBs) from Hydrophobic Solutions Extracts of Fish and Dialysates of Semipermeable Membrane Devices (SPMDs). In Environmental Immunochemical Methods, ACS Symposium Series 646 American Chemical Society Washington, D.C. Chapter 26, pp 307-325. 

Petty, J.D. Huckins, J.N. Robertson, G.L. Cranor, W.L. Gale, R.W. Alvarez, D.A. Clark, R.C. 2002, The application of semipermeable membrane devices (SPMDs) as samplers of airborne contaminants in indoor air. Presented at die 53 Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, March 16-22, 2002 New Orleans, LA. 

Over the last decade, the growth in SPMD research and applications has been remarkable. Reports on this work have been in the form of graduate degree (masters and Ph.D.) theses, abstracts from presentations, laboratory reports, journal articles and book chapters. Herein, we provide the reader with a list of SPMD related peer-reviewed journal articles and book chapters. However, we do not claim that this list is complete and apologize in advance to authors of articles not included. In light of the current rate of the publication of SPMD related articles, additional papers will undoubtedly be available by the time this book is published. 

Koci, V. Lukavsky, J. Mlejnek, M. Kochankova, L. Grabic, R. Ocelka, T. 2004a, Application of a semipermeable membrane device (SPMD) for assessment of organic toxicants dangerous to the green microalga Scenedesmus subspicatus. Arch. Hydrobiol. 150 173—186. 

Ocelka, T. Prazak, J. Koci, J. Raclavska, H. Grabic, R. 2003, Application of the SPMD method for POPs monitoring and toxicity assessment in waste waters. Vodni Hospodarstvi. 53 211-214. 

Czech Republic). Development and application of semipermeable membrane devices (SPMDs) as environmental dosimeters for PCB contaminants in water, air, sediment, and soil is the subject of ongoing research by Huckins and Petty at Columbia Environmental Research Center in Missouri. Also at the Columbia Environmental Research Center, C. Orazio et al. are developing analytical methods for determining PCBs in environmental matrices. A reliable method for continuous monitoring of PCBs in incinerator stack gas emissions using resonance-enhanced multiphoton ionization spectroscopy in conjunction with time-of-flight mass spectroscopy (REMPI/TOFMS) is the topic of current research by... 

The recovery of compour ds trapped inside the membrane is achieved by dialysis using an organic solvent such as hexane [97], cyclohexane [78,138], or by microwave-assisted extraction [149]. Setkova et al. give an overview of SPMD application for monitoring pollutants in various matrices [121]. 

Table 11 summarizes the main applications of conventional dialysis in the extraction of SPMDs devices used in air monitoring of PAHs. It can be observed that, in all cases, extraction times of 48 h, and organic solvent volumes higher than 200 mL, are required. 

Although Rs values of high Ks compounds derived from Eq. 3.68 may have been partly influenced by particle sampling, it is unlikely that the equation can accurately predict the summed vapor plus particulate phase concentrations, because transport rates through the boundary layer and through the membrane are different for the vapor-phase fraction and the particle-bound fraction, due to differences in effective diffusion coefficients between molecules and small particles. In addition, it will be difficult to define universally applicable calibration curves for the sampling rate of total (particle -I- vapor) atmospheric contaminants. At this stage of development, results obtained with SPMDs for particle-associated compounds provides valuable information on source identification and temporal... 

Research stndies employing exposnres of organisms to SPMD extracts in a physiologically nentral medium are increasingly being applied. We envision that this approach will continue to find application in a wide variety of contaminant assessment research studies. 

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