Receptor Models

Receptor models seek to identify or locate sources on the basis of data from the receptor site. The simplest of these use wind direction or back trajectories to qualitatively examine the sources associated with individual samples collected at the receptor site. More complex, quantitative models based on back air trajectory analysis, also called hybrid receptor models, have been developed to locate the source regions of atmospheric SVOCs. These hybrid receptor models include the potential source...

Vibrational Spectroscopic Studies

In order to achieve a mechanistic understanding of NOC interactions with soil constituents, adapted spectroscopic methods sensitive to molecular interactions are required. Sorption data are macroscopic in nature and therefore, are fundamentally insensitive to molecular phenomena (Johnston and Sposito 1987). In the case of NAC sorption to clay minerals, vibrational spectroscopy, in particular, has provided molecule-level insights about the sorption mechanisms on several different aspects. In...

Transport Models

The detection of many POPs in polar areas far from sources prompted the development of model-based approaches to assess the long-range transport potential (LRTP) of SVOCs, including calculating a chemical's characteristic travel distance (Scheringer 1996, 1997 Bennett et al. 1998 Beyer et al. 2000) or persistence and spatial range (Scheringer 1996). These models are discussed in more detail in Chapter 10, and therefore are only briefly mentioned here. Multimedia mass balance models such as...

Contributors

Aboul-Enein, Pharmaceutical and Medicinal Chemistry Department, Pharmaceutical and Drug Industries Research Division, National Research Center, Cairo, Egypt Dr. Imran Ali, Department of Chemistry, Jamia Millia Islamia (Central University), New Delhi, India Dr. Hans Peter H. Arp, Norwegian Geotechnical Institute, Department of Environmental Engineering, Oslo, Norway Dr. Damia BarcelO, Department of Environmental Chemistry, IDAEA-CSIC c Jordi Girona, Barcelona, Spain Dr. Mark J....

Spr

Using this approach, binding affinities and activities of certain known estrogen mimics were determined for their use as calibrator molecules. Results indicated thatrhERalpha and rhERbeta may be employed as probes to distinguish estrogen mimics with a broad range of affinities. In another example, Dutta et al. (2007) developed a nanomechanical transducer to detect endocrine-disrupting chemicals (EDCs) by combining fluidic sample injection and delivery with...

Spme Theory And Principles

The SPME principle relies on placement of a thin polymeric coating coated on the outside of fused-silica fiber directly to the sample matrix or to the headspace above it for a predetermined period of time (Fig. 15.2) (Pawliszyn 1997). As soon as the coated fiber is placed in contact with the sample, analytes partition by adsorption or absorption from the sample matrix to the extracting phase (Pawliszyn 1997 Mills and Walker 2000). As soon as the analyte concentration Barrel - Plunger Retaining...

Experimental Models

The biodegradability of a synthetic chemical is probably one of the most important factors for predicting its environmental behavior. The possibility of a relatively rapid biodegradation under natural conditions will further the chemical's use. However, the absence of biodegradation will result in its restriction or even complete banning. It will also force a search for alternative chemicals of lesser risk to the environment. Accordingly, a series of normalized protocols or tests is needed to...

Z

Many types of passive samplers have been deployed for air sampling, ranging from SUMMA canisters to SPME, semipermeable membrane device (SPMD), and Polyurethane foam (PUF) samplers. Passive sampling has been effectively used to assess workplace contaminants in air such as nitrogen monoxide (NO), sulfur dioxide (SO2), ammonia, VOCs, formaldehyde, and ozone. The applications of passive sampling involve, for example, screening for the presence or absence of...

Photooxidation Of Organic Compounds On Ironbearing Minerals

Iron is the most abundant transition element in the Earth's crust (5 -6 ), which is originally released from magmatic rocks through aerobic weathering in both terrestrial and marine environments and reprecipitates as iron(III) (hydro)oxides or in clay minerals (Cornell and Schwertmann 2003). Iron oxides, hydroxides, and oxide-hydroxides compound are ubiquitous components of soils and sediments (Table 4.1), collectively referred to as iron oxides in this chapter. They play important roles in the...

References

Aas, W. and Breivik, K. (2008), Heavy metals and POP measurements, 2006, inEMEP Co-operative Programme or Monitoring and Evaluation of the Long-Range Transmission of Air Pollutants in Europe, Norwegian Institute for Air Research, Kjeller, Norway. Achman, D. R., Hornbuckle, K. C., and Eisenreich, S. J. (1993), Volatilization of polychlorinated biphenyls from Green Bay, Lake Michigian, Environ. Sci. Technol. 27, 75-87. Anderson, M. J., Miller, S. L., and Milford, J. B. (2001), Source...

Measurement And Modeling Of Semivolatile Organic Compounds In Local Atmospheres

Some Important Semivolatile Organic Compound (SVOC) Classes 6.2.1. Persistent Organic Pollutants 6.2.2. Polycyclic Aromatic Hydrocarbons 6.3.2. Chemical Reaction of SVOCs in the Atmosphere 6.6.1. Diagnostic Ratios and Fingerprints 6.6.2. Other Techniques of Source Identification

Pankow Absorption Adsorption Model

In the early 1990s there were an increasing number of studies reporting correlations between the total organic carbon (TOC) content in aerosols and Kip values for apolar SVOCs. Thus, the hypothesis emerged that OM absorption might be more important than surface adsorption. Pankow (1994b) showed, using derivations from basic partitioning theory, that even if absorption were the dominating mechanism, the resulting SP-LFER would be similar, as can be derived as follows. Assuming that the entire...

Redox Potential

The third master variable that determines the fate of organic pollutants in soils and sediments is redox potential. Only a few functional groups are oxidized or reduced abiotically in the environment (Schwarzenbach et al. 2003). This is in stark contrast to the number of organic pollutants that can be degraded by the microbiologically mediated redox process. However, there is great difficulty in distinctly delineating a redox process as being biotic or abiotic, because abiotic reactions are...

Primary And Secondary Pop Sources And The Role Of Recycling

Persistent organic pollutants (POPs) can be divided into intentionally and unintentionally produced compounds, with the former representing pesticides such as DDT or HCHs that are usually applied openly to the environment, and industrial chemicals (e.g., PCBs) that are partly used in closed systems. The latter are byproducts, for example of incomplete burning processes where PAHs, PCDDs, and PCDFs may form. These sources, including releases due to accidents or inappropriate disposal, are...

Calibration In Spme

In contrast to some traditional sample preparation methods, SPME is a nonexhaustive sample preparation method in which only a small proportion of target analyte is removed from the sample matrix. Therefore, the selection and optimization of calibration methods for quantitative analysis must be given thorough consideration. The purpose of the following section is to present a general overview of both the traditional and more recently developed novel and high-throughput calibration approaches....

Quantitative Description Of Ppcp Environmental Fate

Owing to the presence of different PPCP species and the multiple interaction mechanisms associated with PPCPs, it will be necessary to consider PPCP models different from those used to model HOC sorption. Several typical models describing PPCP sorption in soils sediments are summarized in Table 7.8. Because different species of certain PPCPs have different sorption coefficients, the overall sorption coefficient could be viewed as contributions of the different species. This idea could be...

Recalcitrancepersistence Of Organic Compounds

Organic compounds that persist for long periods in environmental compartments, such as soils, subsoils, aquifers, surface waters, and aquatic or marine sediments, irrespective of the reason of persistence were designated recalcitrant (Alexander 1973, 1999). In the scientific literature, the two terms recalcitrance and persistence are used synonymously. Research and scientific debates on recalcitrance have from the beginning involved the issues microbial infallibility versus. microbial...

Mechanisms Of Organic Contaminant Phytoremediation

Plants employ several mechanisms to remediate soils contaminated with organic pollutants. The following section briefly describes the mechanistic basis for these processes a more detailed description of the processes involved can be found in the later sections on individual contaminant classes. The processes are as follows 1. Plants exude various enzymes that can directly degrade organic contaminants (phytodegradation). 2. Plant roots also release a wide range of nonenzymatic organic substances...

Microbial Transformation of PCBs

Microbial degradation can occur as a result of either mineralization or cometabolism (Boija et al. 2005). In mineralization the organisms use PCBs as both the energy source and the carbon source. Cometabolism involves the use of another compound as the carbon and energy sources, but the PCB is also degraded as a corollary of the metabolic process. The limitation with cometabolism is that if it does not produce compounds that can be mineralized by the organism, incomplete degradation occurs,...

Info

Notation DW drinking water GW groundwater SW surface water WW wastewater. Notation DW drinking water GW groundwater SW surface water WW wastewater. functionalities. They are developed and used because of their more-or-less specific biological activity and are most notably characterized by their ionic nature. The molecular weights of the chemicals investigated in the environment typically ranges from 200 to 1000 Da (daltons). Certain protein molecules possessing therapeutic properties have also...

Biodegradation Of Anthropogenic Organic Compounds In Natural Environments

Niqui-Arroyo, Marisa Bueno-Montes and Jose-Julio Ortega-Calvo 19.2. Contrasting Basic Concepts in Biodegradation 19.2.1. Metabolism Versus Cometabolism 19.2.2. Biodegradability Versus Bioavailability 19.2.3. Aged Versus Bound Residues 19.3. Experimental Models and Radioisotope Tracers in Biodegradation Research 19.3.2. Radioisotope Tracers (14C) 19.4. Interactions of Anthropogenic Organic Chemicals and Microorganisms with Geochemical Components and their Effects on Biodegradation...

Inverse Gas Chromatography

Inverse gas chromatography (IGC) uses the same equipment and principles as gas chromatography the main difference is that IGC experiments are conducted to characterize the sorption behavior of the stationary phase, and not to characterize the injected sorbents (i.e., the column packing material itself is what is being studied). The basic design of an IGC suitable for experiments conducted at environmental conditions is shown in Figure 5.3. In IGC experiments the carrier gas (typically nitrogen...

Eukaryotic Organic Transformation

Phytovolatization

Yeast and fungi have the ability to degrade organic pollutants. For example, Hammer et al. (1998) was able to isolate and show that the yeast Trichosporan mucoides degrades dibenzofuran. Similarly, Beaudette et al. (1998, 2000), experimenting with two di- and tetrachlorinated PCB congeners and one each from the tri- and hexachlorinated congeners, reported 15 -65 degradation of all 6 PCB congeners by white-rot fungi. In another study, Tricho-sporan mucoides and the fungus Paecilomyces lilacinus...

Photosensitized Degradation Of Organic Pollutants On Titanium Dioxide Surface Under Visible Irradiation

Textile dyes and other industrial dyestuffs constitute one of the largest groups of anthropogenic organic compounds that represent an increasing environmental risk. There are more than 100,000 commercially available dyes with over 7 x 105 tons of dyestuff produced annually (Zollinger 1987). It has been estimated that about 10 -20 of the total world production of dyes is released into the environment from textile, paper, printing industries, and dye houses (Claus et al. 2002). These dyes have...

Future Developments in Synchrotron Based FTIR Microscopy

Lombi and Susini (2009) provide a fairly exhaustive review of the literature relevant in the main to X-ray microscopy techniques, including STXM, but also with reference to FTIR and other synchrotron-based techniques. In addition, they consider future directions and required developments quite extensively. In general, it is anticipated that there will continue to be considerable improvement in optics, detectors, and software related to FTIR spectromicroscopy and other synchrotron techniques,...

Fate And Transport Of Organic Compounds Into The Subsurface Environment

Introduction Subsurface Pollution 8.1.1. Overview of Relevant Organic Compounds 8.1.2. Persistence in the Subsurface Environment 8.1.3. Equilibrium Distribution in the Three-Phase System Soil Solids, Air, and Water 8.2. Sorption Desorption Kinetics 8.2.2. Hysteresis in Diffusion-Limited Sorption Desorption Kinetics 8.2.3. Sorption and Biodegradation 8.3. Reactive Transport in the Subsurface Environment 8.3.1. Vapor-Phase Diffusion in the Unsaturated Soil Zone 8.3.2. Diffusion and Reaction...

Metabolism Versus Cometabolism

Many of the transformations of AOCs occurring in the environment are due to the assimilation of the chemicals by microorganisms. The molecular structure is enzymatically attacked to obtain the elements (mainly C, but also N, P, and S) and or the energy needed to build up biomass and sustain microbial cell activity. The same biochemical strategy as for a hexose or a fatty acid is used for assimilation the AOC molecule is converted into metabolic intermediaries that serve as polymer building...

Overview of Sorbent Sorbate Interactions

In order to make gas particle partitioning models that are more robust than those described in Section 5.3 for diverse organic compounds, it is necessary to look at the specific sorbent-sorbate interactions involved in partitioning, and how these influence yz. Sorbent-sorbate interactions can be classified as specific and nonspecific, which are synonymous for polar and apolar interactions. Nonspecific interactions are called such because they do not occur between specific locations of the...

So3h

Dye (Wu et al. 1999a, 2000), basic blue dyes (Stathatos et al. 2001), diazo dye (naphthol blue-black) (Nasr et al. 1996), phenosafranin dyes (Ziolkowski et al. 1997), Active Brilliant Red Dye X-3B (Xie et al. 2005 Xu and Langford 2001), and Reactive Red 198 (Kaur and Singh 2007). Wu et al. (1999b) investigated the photodegradation of a series of dyes (Rhodamine B, Orange II, Sulfu-rhodamine B, fluorescein, alizarin red, squarylium cyanine, and eosin) in the presence of TiO2 particles under...

Popek 2003 Chromatography References

American Society for Testing and Materials (2009), ASTM D1586-08a StandardTest Methodfor Standard Penetration Test (SPT) and Split-Barrel Sampling of Soils available at http astm.nufu. eu std ASTM 20D1586 20- 2008a (accessed Jan. 2009). Arthur, C. L. and Pawliszyn, J. (1990), Solid phase microextraction with thermal desorption using fused silica optical fibers, Anal. Chem. 62, 2145-2148. Axelman, J., Naes, K., Naf, C., and Broman, D. (1999), Accumulation of polycyclic aromatic hydrocarbons in...

Osa

Schematic (not to scale) of 10ID1 beamline and STXM at the Canadian Light Source (CLS) (EPU elliptically polarizing undulator M1,M3 mirrors PGM plane-grating monochro-mator OSA order-sorting aperture exit slit also acts as a spatial coherence filter. (NSLS), two (soon to be three) at the Advanced Light Source (ALS) (Kilcoyne et al. 2003), the Canadian Light Source (CLS), Elettra (Italy), and the Swiss Light Source (SLS). In addition, beamlines are under construction at the Stanford...

Aerosol Sources Composition and Size Fractions

In any given ambient atmosphere, the aerosols present come in many shapes and sizes and from many different sources. Understanding the makeup, composition, and origin of atmospheric aerosols is quite a complex and broad field, and the field of aerosol science is an extensive branch of science in its own right. Here, we will focus briefly on particular aspects that are of direct relevance to ambient gas particle partitioning. Readers interested in further details are referred to relevant...

Sample Extraction Protocols

Sample extraction is an integral part of the analytical process. In general, there are two types of extraction methods solvent extraction and nonsolvent extraction. A solvent extraction method attempts to recover as much of the analytes as possible within the shortest possible time, and can be characterized as an exhausted extraction method. The basic principle of solvent extraction is the distribution of the analyte(s) between a selected solvent or solvent mixture and the sample being...

Persistent Organic Pollutants

Persistent organic pollutants (POPs) are a class of chemicals characterized by their long-term persistence in the environment, significant toxicity, and global distribution. There has been significant international effort to curtail or eliminate the usage of a certain group of POPs known initially as the dirty dozen or more recently as PBTs (persistent bioaccumulative toxic chemicals). As such, when referring to POPs, most are actually speaking of this smaller group of compounds. The...

Photochemical Reactions

Photochemical reactions are diverse and are mediated by the fission product of water (OH, H) and molecular oxygen or its excited states. Therefore, the photochemical effect can be broken down into two broad categories (1) photolysis, which is light-induced hydrolysis and (2) photoredox reactions. These can be further subdivided into hydrolysis, elimination, oxidation, reduction, and cyclization. There is no hard-and-fast trend with respect to photolysis, and it is highly compound-dependent. It...

Hpcd

Obtain concentration after extraction with HPDC Reid et al. (2000a), Cuypers et al. (2002), Doick et al. (2005, 2006), Hickman and Reid (2005), Stokes et al. (2005b), Allan et al. (2006), Barthe and Pelletier (2007), Papadopoulos et al. (2007a), Rhodes et al. (2008a,b), Stroud et al. (2008) Consecutive extractions of aqueous phase with Tenax Use regression model to estimate rapidly desorbing fraction Cornelissen et al. (1998), White et al. (1999), Kraaij et al. (2002), Oen et al. (2006), Chai...

Polycyclic Aromatic Hydrocarbons

Another important class of SVOCs is PAHs, which are produced mainly from combustion processes and petrogenic sources (e.g., coal, oils, fossil fuels). Some PAHs are produced naturally from forest fires and volcanic eruptions, but anthropogenic emissions of PAHs from fossil fuel burning tend to dominate in most areas (Wild and Jones 1995). Petrogenic sources are the main source of PAHs in areas impacted by oil spills and fossil fuel contamination (e.g., by unburned coal), such as shipping ports...

Diagnostic Ratios and Fingerprints

The simplest approach to source identification is to match concentration ratios of compounds, congener profiles, or fingerprints to specific sources. This fingerprinting approach has been used extensively for the variety of sources associated with different SVOCs. Table 6.4 summarizes some of the different strategies used to identify atmospheric sources of SVOCs. 6.6.1.1. PCBs. The industrial use of PCBs in the United States was limited primarily to technical mixtures manufactured under the...

Fluorine

Up to this point, all the nuclei discussed have been natural constituents of NOM, which is the sorbent of interest. The same cannot be said about fluorine. This means that the only organic (there are natural forms of inorganic fluorine e.g., fluorite and fluorapatite) fluorine signal within an environmental matrix should be from human input. Stated another way, there should be no natural organic fluorine, and hence, no fluorine background signal. In addition, 19F is 100 naturally abundant, is...

Biosensors For Environmental Monitoring

The following sections present and discuss the development of biosensors for environmental applications classified according to the main biological recognition elements used in biosensors for the analysis of target compounds or the assessment of whole biological effects. The first biosensor, described in the literature by Clark and Lyons (1962), was based on the use of glucose oxidase with electrochemical detection. Also, the first applications developed for environmental analysis were based on...

Optimization Of Spme Methods

In the practical application of SPME, a variety of experimental factors need to be considered and addressed for a particular system under investigation. Selection of the parameters that affect SPME extraction efficiency is dependent mainly on the target analytes of interest, sample matrix, and objectives of analysis (Risticevic et al. 2010b). The parameters affecting sensitivity and reproducibility of SPME methods are displayed in Figure 15.3 and are thoroughly discussed in the following text....

Organic Carbon Normalization

One traditional method that has been employed to estimate bioavailability is to normalize the total contaminant concentration to the OC content of the soil or sediment. This method works according to the principles of chemical activity and EqP. Organic carbon normalization has been effective in estimating bioavailability and generally predicts toxicity within a factor of 2-3 (Di Toro et al. 1991). This method implies, however, an assumed constant KOC value for a given contaminant, thus ignoring...

Partial Extraction Methods

Extraction methods are designed to only remove contaminants that are rapidly desorbing, since this is the fraction generally thought to be bioavailable to organisms over a relevant timescale (Cornelissen et al. 2005). Thus, these approaches are not designed to be exhaustive. These methods include mild solvent extraction, cyclodextrin-aided desorption, and Tenax-aided desorption. 21.4.2.1. Mild Solvent Extraction. Mild solvent extraction generally uses moderately polar organic solvents to...

Ppcp Degradation

Pharmaceuticals and personal care products can quickly degrade in the environment, with half-lives generally within one month (Cousins et al. 2002 Lucas and Jones 2006 Accinelli et al. 2007), especially in an aerobic environments (Ying et al. 2004 Ying and Kookana 2005). Therefore, PPCPs have been reported to be nonpersistent in the environment (Klecka et al. 2001 Lucas and Jones 2006). It should be mentioned that because PPCPs are continuously entering the environment, their concentrations are...

Chemical Reaction of SVOCs in the Atmosphere

The extent to which SVOCs react in the atmosphere can dictate their long-term environment fate. If the atmospheric degradation reactions are slow compared to the rates of deposition, then a greater proportion of the emitted SVOCs could reach human and terrestrial food chains. Atmospheric SVOCs can be removed by photodegradation, including direct photolysis and indirect photolysis, that is, reaction with photochemically generated radicals. Direct photolysis in the atmosphere of a given compound...

Summary And Perspectives

The widespread application and occurrence of PPCPs in the environment has raised concerns of PPCP environmental and health risks. The data available on the occurrence of PPCPs in soils sediments are very limited because of the analytical challenges for solid matrix samples. An extensive survey of PPCP distribution in solid environmental media is needed. The environmental behavior of PPCPs is controlled mostly by their interactions with soils and sediments. Further, PPCP sorption in soils...

Aged Versus Bound Residues

Biodegradation can be slow with AOCs that have been present in the environment for a long time but can still be extracted with vigorous solvent extraction, forming the so-called aged residues, of limited bioavailability (Alexander 2000). However, chemicals can also become not extractable at all. The concept of bound residue originally defined for pesticides by the International Union of Pure and Applied Chemistry (IUPAC), and later extended to other AOCs and their metabolites is basically...

Cl O Cl Cl

Illustrative diagram for the effect of total cation concentration and species on PPCP sorption. If the PPCP sorption mechanism is dominated by metal bridging, an increased PPCP sorption may be expected with increased total cation concentration. However, if PPCP sorption is controlled by cation exchange, increased total cation concentration may result in decreased PPCP sorption. The cations may exist as free dissolved, sorbent-sorbed, and PPCP-complexed ions. Knowing the species of...

Np

As well as on the prevailing reaction conditions environmental parameters . In particular, oxygen availability seems a significant environmental reaction parameter with regard to transformation of nonylphenolic compounds. Under strict anaerobic conditions, NP turns out to be the end product of NPnEO transformation Ahel et al. 1994a Montgomery-Brown and Reinhard 2003 . Under aerobic conditions further transformation of certain NP isomers by ipso substitution Corvini et al. 2004,2005,2006 Gabriel...

Sampling And Analysis

Chapter 12 provides more detail on methods of measuring SVOCs in air. This section therefore summarizes the main methods used in monitoring studies and highlights issues of quality assurance and quality control that can affect the usefulness of the data generated. 6.5.1.1. Active Air Sampling. Currently, the high-volume air sampler is the most widely used approach for sampling SVOCs in air. This active sampling approach utilizes a pump that draws air through a filter to retain the...