To demonstrate the versatility of Fourier transform infrared (FT-IR) spectrometry, two site investigations are discussed. The first is the monitoring of emissions from active volcanoes. The second is the analysis of soil gases from a site that is currently under remediation for ground water and soil contamination. The monitoring performed at the volcanoes used open- path FT-IR methods and the monitoring at the remediation site used extractive FT-IR methods. Descriptions of the sampling systems employed and the emissions monitored at these sites are used to demonstrate the advantages and limitations of environmental monitoring using FT-IR spectrometry.

Modern techniques for on-line process control require versatile monitoring mthods which combine high sensitivity with high selectivity. In this paper a novel REMPI-mass spectrometer is presented. In comparison to standard instruments, sensitivity is increased by shifting the ionization regime to the vicinity of thecontinuum portion ('jet') of the sample beam as opposed to the more conventional ionization under molcular beam conditions. A further gain in sensitivity is achieved by increasing the ionization volume. This was made possibl eby a complete redesign of the ion source. A very low base-line level is achieved by choosing a geometry preventing secondary ionization through thecollisions of ions/electrons with surfaces. These innovations have resulted in excellent performance from our apparatus as demonstrated by the dichorotoluene and naphtalene spectra obtained under various conditions. For naphtalene we have now a detection limit of 5 ppt (more fraction) for S/N equals 1 in 20 sec. Further developments of the technique and research needs ae discussed.

This research reports on a new innovation in chemical measurement technology that combines open-path Fourier transform infrared (OP-FTIR) spectroscopy with computed tomography to create two-dimensional maps of air contaminants that are both spatially and temporally resolved. This method has been evaluated with numerical studies that tested different iterative reconstruction algorithms and OP-FTIR configurations. The success of this system for characterizing the flow of contaminants in air, exposure assessment, emission monitoring and leak detection, was closely linked to the choice of reconstruction algorithm and configuration. A systematic method was developed to evaluate these parameters using static and time series test maps under ideal and non-ideal sampling conditions. Concentration map quality was evaluated using qualitative and quantitative criteria. Map reconstruction quality using different algorithms and configurations was found to be intimately related to the complexity of the test maps. The results of this research underscore the need to thoroughly test the system through numerical studies prior to field implementation; a wide variety of concentration maps, relevant to the application, should be tested under both ideal and non-ideal sampling conditions.

The infrared and ultraviolet emission spectra of hydrocarbons and toxicants was measured and analyzed as compared to theoretical data at room temperature. Based on this data we constructed an electro-optical gas detector for monitoring low concentration of flammable paraffins, aromatics and toxic hydrogen-sulfide. The optical method uses two wavelengths at several spectral bands: the signal and the reference which is sampled at a region where the hazardous gas does not absorb at all. Our apparatus is an innovative system that provides fast and reliable explosion detection at different lower explosion levels (LEL). As well, it can provide identification of low concentration of toxicants in the range of parts per million. The apparatus includes a fire detection option that can offer at the same time an automatic activation of fire suppression or neutralization system. It can detect paraffins in the range between 0.03 to 20 LEL per 1 meter by using the ultraviolet spectral band. At both regions the accuracy is about 20%. This open-path, line-of-sight gas detector can monitor and transmit an alarm signal prior to occurrence of fire or explosion.

Systematic and reproducible methods of evaluating fiber-optic probes and laser sources for Raman spectroscopy have been developed. We have investigated the performance of two different types of external cavity diode laser sources for Raman spectroscopy. These lasers were evaluated in terms of long-term wavelength drift and power stability. Experimental methods and computer-generated models were developed to evaluate fiber-optic Raman probe performance under a variety of conditions and for a variety of sample types. Performance parameters investigated include probe sensitivity, sampling volume, and discrimination against fiber-optic silica background. Sample types studied include clear liquids and solids, highly scattering solids and slurries, and highly absorbing liquids and solids.

Two fluorescence sensors that are much simpler and less expensive than conventional laser based devices have been developed. The sensors are designed to be deployed in cone penetrometers, utilizing a mercury lamp in the cone for excitation of either a down-hole filter- photomultiplier combination or an up-hole multichannel spectrometer for detecting emission. Both sensors are demonstrated to be useful for rapid, in situ detection of fuels at concentrations ranging to below 100 ppm (a typical action level for cleanup) in soil.

A laser-induced fluorescence (LIF) excitation-emission matrix (EEM) probe has been developed for subsurface monitoring of fluorescent organic contaminants. The fourth harmonic of a flashlamp-pumped Nd:YAG laser (at 266 nm) is used to pump a Raman shifter. Up to ten laser beams (in the wavelength region of 258 to 379 nm) from the raman shifter are launched into optical fibers that conduct the light to the probe near the tip of the cone penetrometer. The fluorescence emission is excited through ten separate sapphire windows and collected by ten collection fibers that conduct the fluorescence to a spectrograph/CCD detection system. This probe allows real-time collection of LIF-EEMs of contaminants adsorbed on solids or dissolved in groundwater. LIF-EEMs provide a substantial amount of spectral information that can be used to determine the composition and quantity of contaminants in soils. The system was tested and calibrated in the laboratory. Spectra of different organic contaminants were measured in aqueous solutions, in organic solvents, and in different types of soils.

Infrared fiber optic reflectance spectroscopy is a powerful tool for identifying various organic compounds in soils. Using this technique a mixture of benzene and TCE on sand was measured; peaks due to both compounds are readily evident and correspond to the peaks in the pure liquid. At low concentrations of diesel fuel marine (DFM) on sand the band depths scale linearly with respect to DFM concentration. As the DFM concentration increases, the plot of DFM band depth versus concentration becomes nonlinear.

The current status of a fiber optic laser induced breakdown spectroscopy probe for subsurface deployment via a cone penetrometer truck is discussed. In this work the parameters involved in delivering both the LIBS excitation and emission over optical fibers are discussed and laboratory detection limit results for Pb contaminated sand and soil are presented from a prototype FOLIBS probe.

The oxidation effects of an ozone treatment using naphthalene (NAP), phenanthrene (PHE), pyrene (PYR) and a mixture of these polycyclic aromatic hydrocarbons (PAHs) adsorbed on solid phases were studied. Due to ozonation, a decrease of the applied concentrations of each of the investigated compounds with respect to their molecular weights occurred (up to 86% for NAP, 73% for PHE and 50% for PYR). After ozonation, the formation of o-phthalaldehydic acid, o-phthalaldehyde, o-phthalic acid, oxalic acid, acetic-acid, formic acid, and diphenic acid was observed as oxidation products. Dependent on dosage, ozone was even able to oxidize the PAH to carbon dioxide and water to a certain extent.

The flow-field-flow-fractionation (Flow-FFF) is a sensitive and gentle technique for the size measurement and separation of macromolecular and particulate matter. Its theoretical fractionation power extends across a broad size spectrum ranging from about 1 nanometer to several micrometers. In a first step the optimal working conditions for applications on environmental aquatic colloids have been evaluated. Subsequently, a calibration procedure using certified polystyrene latex microspheres of different sizes was carried out. The influence of electrolytes on the fractionation process was tested with several experiments carried out in ground water. To control the fractionation process, most of the eluates were collected and examined by scanning electron microscopy (SEM). The results show that excellent fractionation results are obtained for particles with diameters between 30 nm and 500 nm. For bigger particles the fractionation becomes increasingly inexact (e.g. broad elution peaks), thus the resolution is deteriorated. Based on these results the size distribution of a commercial humic acid before and after coagulation was determined.

A mobile fiber-optical sensor system for the on-line and in situ detection of aquatic fluorophores has been developed. By the use of time-resolved laser-induced fluorescence spectroscopy the determination of contaminants, i.e., polycyclic aromatic hydrocarbons (PAH) or fluorescence tracers in various environments, is possible. In both cases attempts to detect these substances in water by means of fluorescence spectroscopy are complicated by the low concentrations and the overlapping and featureless fluorescence spectra in combination with background fluorescence caused by further compounds, e.g., humic material. By collecting the fluorescence decay time as an additional independent dimension, the analytical information is significantly increased, and to a certain extent the determination of the desired analyte in complex natural matrices is possible. At a first application, the detection of pyrene (PYR) in real samples from a contaminated former coking plant site has been realized. The system is also best suitable for hydrogeological research. Here applications spread from the investigation of the fluorescence tracer migration in an artificial aquifer system to the determination of hydrogeological parameter at a domestic waste disposal.

Immunoassays are useful analytical instruments for the detection of many environmental compounds. This method is now introduced for the detection of non-extractable compounds in soil. So-called 'bound residues' consist of a soil component, e.g. humic acids, and an irreversibly bound pollutant. Because of the complexity of those macromolecules conventional analytical methods in general do not work. Enzyme immunoassays, in contrast, seem to have a large potential for applications and further developments in this field. The use of antibodies with high affinity to the analytes makes a selective detection of environmental pollutants possible. With the development of an enzyme-labeled sandwich-immunoassay polycyclic aromatic hydrocarbons (PAHs), irreversibly bound to humic acids, were determined for the first time.

The paper describes three new approaches to the analysis of pesticides in aqueous samples: (1) coupling of high performance liquid chromatography (HPLC) to mass spectrometry (MS) using thermospray ionization (TSP); (2) on-line-solid phase extraction (SPE) coupled to HPLC/MS; and (3) in-line coupling of solid phase microextraction (SPME) to gas chromatography (GC) and GC/MS. These methods can be readily automated and allow a rapid analysis of pesticides in aqueous samples at the low ppt-level.

We report on an optical cuvette test for total heavy metals based on the inhibition of the enzyme urease by metals ions including silver(I), mercury(II), copper(II), nickel(II), cobalt(II), and cadmium(II). The enzymatic action is monitored using an optical ammonia transducer deposited on the wall of a disposable cuvette. This results in a rapid and inexpensive single-shot device for heavy metal sensing. A solution of urease and buffer is placed in the cuvette with the ammonium sensor membrane fixed on one of its walls. Enzymatic action starts after addition of a defined quantity of urea. This is indicated by the increase in the absorption of the ammonia sensor membrane whose color changes from yellow to blue. The slop of the increase in signal is the information for the un-inhibited reaction. After several minutes,the sample (containing the heavy metal) is added to the cuvette. Heavy metal ions inhibit the enzyme (by binding to the sulfhydryl groups) and cause a decrease in the slope. The ratio of slopes of un-inhibited and inhibited reactions is a direct parameter for detecting and calculating total heavy metals. The optimum pH was a trade-off between optimum enzyme activity (pH 7 at 25 degree(s)C) and the relative signal change of the ammonia-sensor (highest at pH 8). pH 7.5 was found to be optimal. The system was calibrated at optimized activities of urease (1.5 (mu) ) and an optimized urea concentration (0.5 mmol). Heavy metals inhibit in the following order: Ag(I) > Hg(II) > Cu(II) >> Ni(II) > Co(II) > Cd(II) > Fe(III) > Pb(II), Zn(II). The following concentrations that cause 50% inhibition were found: Ag(I) (0.1 ppm), Hg(II) (0.5 ppm), Cu(II) (0.5 ppm), Ni(II) (7 ppm), Co(II) (30 ppm), Cd(II) (95 ppm), Fe(III) (50 ppm), Zn(II) (85 ppm) and Pb(II) (210 ppm). We also studied the inhibitory effect of combinations of metal ions, the influence of ionic strength, and the effect of incubation time.

A bioelectrochemical method for the determination of heavy metal ions has been developed. This method is based on the inhibition effect of metal ions on the enzymatic activity of oxidase enzymes. The enzymatic activity was determined with an amperometric hydrogen peroxide probe. The inhibition effect on enzymes in solution and covalently immobilized on polymeric supports has been evaluated. Hg(II) was the metal ion that inhibited almost all the enzymes, particularly glycerol-3-P oxidase. Hg(II) was detected in the 0.05/0.5 ppm range with the enzyme in solution. Calibration curves for Hg(II) were also obtained with the other oxidase enzymes in the 0.5/10 ppm range. The other metal ions tested inhibited the enzymes more specifically. The metal ion/enzyme systems which gave the best inhibition were Se(IV)/glutathione oxidase, Ni(II)/sarcosine oxidase, V(V)/glutathione oxidase, Cu(II)/alcohol oxidase from Pichia Pastoris and Cd(II)/D-aminoacid oxidase. All these metal ions were detected in the 0.1/10 ppm range using the enzymes in solution or covalently immobilized.

In conventional trace analysis pretreatment of a sample serves to enrich the substance to be detected. Some compounds polluting the environment are hydrophobic and stick to the soil matrix: therefore organic solvents often are used to prepare samples for environmental analysis. In biochemical analysis the enrichment step may be incorporated in the detection process. The most effective method is the use of immunochemistry; the matrix bound antibodies collect the analyte out of a highly diluted sample. Immunoassays therefore have been introduced successfully for environmental monitoring during the last decade; e.g., for pesticides many immunoassays have been developed and some of them are now commercially available; a recent review is given by Meulenberg et al. However, despite the fact that selectivity and sensitivity of immunoreactions is high, the capability of producing directly useful signals is poor. Many attempts have been made to overcome this limitation by the use of physical, chemical, or biochemical labels. But still there is need for more sensitivity than most immunoassays can achieve. On the other hand immunoassays usually are performed under physiological conditions and only rare data are available about antigen/antibody binding in non-aqueous systems.

Whole blood or plasma from male human volunteers or pooled from male Sprague-Dawley rats was incubated with varying amounts of ³H-2,3,7,8-tetrachlorodibenzo-p-dioxin (³H-TCDD). Blood was separated into cellular, protein and lipoprotein fractions by centrifugation. The distribution of ³H-TCDD between lipoproteins and plasma proteins was independent of ³H-TCDD concentration in the range of 65 fmol-1 nmol/ml plasma. The distribution of ³H-TCDD between the various lipoprotein fractions depended only on their relative content of total cholesterol plus triglycerides. The partitioning of ³H- TCDD between lipoproteins and plasma proteins was inversely proportional, whereas the distribution between the cellular fraction and the lipoproteins was directly proportional to the total plasma cholesterol plus triglyceride content. As a consequence of species differences in blood composition, the major part of ³H-TCDD-associated radioactivity was recovered from lipoproteins in human blood but from erythrocytes in rat blood. A mathematical description of the distribution of TCDD between blood components is presented.

In 1989 the research center, 'Treatment of Contaminated Soils' was set up by the Deutsche Forschungsgemeinschaft (DFG equals German Research Foundation). Within the framework of this special program the Technical University of Hamburg-Harburg (seat of chair) and the University of Hamburg investigate basic methods for the treatment of contaminated soils in 17 projects. The first research periods ran from Jan. 1, 1989 up until Dec. 31, 1994. The third research period will end on 31 Dec. 1997. It is the aim of the research center not just to investigate, develop and optimize decontamination methods but simultaneously to perfect both analytical and measuring techniques thus enabling the swift and comprehensive description of all processes. The primary objective of all projects within the SFB 188 is the clarification and description of mechanisms which either result in decontamination or prevent decontamination. In the following methods and results regarding preinvestigations and enhancement are presented. Preinvestigations are seen as a very important tool to optimize a biological treatment of a contaminated soil. By this means, the possibilities and limitations (how far can the pollutants be degraded) for the specific polluted soil can be predicted. Balances show what actually happens to the pollutants. In order to practice preinvestigations specific test systems must be available. Using these methods the remediation can be realized more cost effectively. Optimizing and enhancing the degradation processes is another measure for cost reduction.

Discrimination of structurally similar analytes by immunoassay is limited by antibody cross reactivity. Using a plurality of cross-reacting antibody species allows increased selectivity by application of pattern recognition methods. We present a detailed characterization of an array of monoclonal antibodies which allows analytical modeling of the performance of an antibody array in a multi-analyte system. Such well defined antibody arrays give the possibility for the systematical optimization for immunoassay applications. Affinity characterization is carried out in a simple test format: After equilibrium binding of antibody and analyte, unoccupied antibody is quantified by an optical transducer. The test result reflects directly the respective affinity constants for different analytes. A set of three monoclonal antibodies was characterized with respect to their affinity to five different s-triazines which play an important role in water contamination. The affinities were compared with results obtained by direct enzyme immunoassay. The analytical performance of the antibody array was modeled by using the affinity constants determined from the calibration curve.

Both slurry-phase and solid-phase bioremediation are effective ex situ soil decontamination methods. Slurrying is energy intensive relative to solid-phase treatment, but provides homogenization and uniform nutrient distribution. Limited contaminant bioavailability at concentrations above the required cleanup level reduces biodegradation rates and renders solid phase bioremediation more cost effective than complete treatment in a bio-slurry reactor. Slurrying followed by solid-phase bioremediation combines the advantages and minimizes the weaknesses of each treatment method when used alone. A biological treatment system consisting of slurrying followed by aeration in solid phase bioreactors was developed and tested in the laboratory using a silty clay loam contaminated with diesel fuel. The first set of experiments was designed to determine the impact of the water content and mixing time during slurrying on the rate an extent of contaminant removal in continuously aerated solid phase bioreactors. The second set of experiments compared the volatile and total diesel fuel removal in solid phase bioreactors using periodic and continuous aeration strategies. Results showed that slurrying for 1.5 hours at a water content less than saturation markedly increased the rate and extent of contaminant biodegradation in the solid phase bioreactors compared with soil having no slurry pretreatment. Slurrying the soil at or above its saturation moisture content resulted in lengthy dewatering times which prohibited aeration, thereby delaying the onset of biological treatment in the solid phase bioreactors. Results also showed that properly operated periodic aeration can provide less volatile contaminant removal and a grater fraction of biological contaminant removal than continuous aeration.

Mercury compounds have been determined with an electrochemical biosensor based on invertase inhibition. When invertase is in the presence of mercury its activity decreases; this causes a decrease of glucose production which is monitored by the glucose sensor and correlated to the concentration of mercury in solution. Parameters as pH, enzyme concentration, substrate concentration, and reaction and incubation time were optimized. Mercury compounds determination using soluble or immobilized invertase were reported. Results show that the inhibition was competitive and reversible. Mercury compounds can be detected directly in aqueous solution in the range 2 - 10 ppb.

Environmental problems are often complex, with multiple causes and diverse ecological effects. Examples can include for example persistent environmental traces of industrial chemicals, pesticides, wastes which have been studied intensively, especially within the group of organochlorines. Dealing with such problems requires a flexible decision-making process that can accommodate this diversity while providing some measure of the uncertainty with decisions that are made.

Hemorrhagic Escherichia coli O157:H7 and other fecal coliform bacteria, such as species of Salmonella, could pose a serious health threat in contaminated water resources. Traditional bacterial culture methods and ELISA based assays for identification of fecal coliforms are relatively slow and ambiguous. Polymerase chain reaction of extracted DNA from such bacteria and immunomagnetic separation (IMS) methods appear promising for this application. Although PCR can be a definitive identification technique, it is relatively time consuming when compared to IMS. In this work, the IMS technique has been coupled with an electrochemiluminescence (ECL) technology to separate specific bacteria from their media and quantitatively detect the bacteria within one hour. The sensitivity of the IMS-ECL assay for E.coli O157 strain and Salmonella sp. is as low as 10 - 100 cells/mL in water samples. In addition, IMS was accomplished in dense washings of food and environmental samples followed by ECL assay. These results suggest strongly use of the IMS-ECL methodology for rapid and facile screening of various bacterial contaminations in water resources or other environmental samples for the low level presence of pathogenic coliforms.

Correct identification and assessment of the prevailing source, scope, and extent of pollution potential is essential for providing efficient preventive remedial actions and management of already occurring contamination on the least-cost basis. In the paper, the identification/assessment procedure for the areas with several sources of long-lasting nonpoint contamination is illustrated by example of the Wroclaw waterworks area in Poland impacted by emission from a ferro-chrome smelter and power plant, as well as by various sources of polycyclic aromatic hydrocarbons. Investigations and studies comprised (1) analysis of physicochemical composition of emitted particulates and deposited wastes, their time- dependent transformations and leachability of contaminants as a function of time; (2) direct multilevel sampling of dump and vadose zone profiles and examination of pore solutions and matrices; (3) ground-water survey in the saturation zone; (4) investigation of infiltration and contaminant migration from radioisotope data; (5) survey of surface water quality; (6) numerical simulation and direct measurements of particulate emission from various sources; (7) analysis and comparison of data on point and nonpoint emission/omission of contaminants with the extent and scope of contamination. In another example, current investigations on the vadose zone screening and monitoring in the area of a high environmental risk in the vicinity of Sendzimir Steelworks near Cracow, Poland are presented.

Time-resolved laser-induced fluorescence (LIF) spectroscopy and laser excitation at 248 nm and 337 nm are applied to investigate fuel and oil contaminations in water with respect to classify between different aromatic hydrocarbons. The quantitative interpretation of the LIF- data is difficult because petroleum products are complex mixtures of hydrocarbons in various compositions. Solvent and concentration effects like fluorescence reabsorption or excimer formation cause a red shift of the fluorescence intensity spectra and a change in time evolution of the LIF-decay spectra. In this paper these effects are discussed with respect to practical applications. A time-integrated photon counting technique applying two different time-gates in combination with fiber optics has been drawn out to simplify the method, so it becomes very attractive for quantitative diagnostics of oil and fuel contaminations in water or soil samples. An example for on-line monitoring is reported.

The cost of characterizing and monitoring U.S. government hazardous waste sites could exceed $500 billion utilizing traditional methods and technology. New sensor technologies are being developed to meet the nation's environmental remediation and compliance programs. In 1993, the U.S. Air Force Armstrong Laboratory and Loral Defense System, Eagan (formerly a division of Unisys Corporation) signed a Cooperative Research and Development Agreement (CRDA) to commercialize fiber optic laser-induced fluorescence technology that had been developed with U.S. Air Force funding a North Dakota State University (NDSU). A consortium consisting of the CRDA partners (USAF and Loral), Dakota Technologies Inc., and NDSU submitted a proposal to the advanced Research Projects Agency, Technology Reinvestment Project and won an award to fund the commercialization. The result, the Rapid Optical Screening Tool or ROST is a state-of-the-art laser spectroscopy system for analysis of aromatic hydrocarbon-contaminated soil and groundwater. With ROST, environmental investigators are able to find, classify, and map the distribution of many hazardous chemicals in the field instead of waiting for reports to come back from the analytical laboratory. The research and development program leading to prototype laser spectrometers is summarized along with results from laboratory and field demonstrations illustrating system performance and benefits for site characterization. The technology has recently been demonstrated in Europe in Germany, the Netherlands, France an several sites in the United Kingdom having light, medium, and heavy aromatic hydrocarbon contamination from fuel spills and refinery or chemical plant operations. The use of the ROST system to find hydrocarbon contamination is now being offered as a service by Loral Corporation.

A compact, ruggedized fiber optic IR reflectance probe for remote, in-situ screening of underground waste sites has been developed. Using cabled chalcogenide optical fibers and a FTIR system, remote spectroscopy has been performed over distances of 20 meters. This paper discusses the design and performance of this system.

A yeast cell biosystem has been recently developed for the total toxicity testing of a sample that may contain a number of different polluting species. The method uses an amperometric gas diffusion oxygen sensor as indicating electrode and is based on the perturbation of the respiratory activity of the immobilized yeast Saccharomyces cerevisiae; glucose acts as substrate. Several toxic substances were tested: metal ions, phenol and cationic, anionic or nonionic surfactants. Some results of a monitoring program of an industrial wastewater are also reported and discussed.

Laser induced fluorescence (LIF) is a powerful technique for in-situ detection of subsurface contamination due to petroleum products. This paper describes the Site Characterization and Analysis Penetrometer System (SCAPS) LIF sensor which combines an LIF spectroscopic system with a cone penetrometer truck, and presents field results from a recent site characterization of a diesel fuel contaminated site. In addition to the LIF sensor measurements performed at the site, 130 soil samples were collected by hollow stem auger with split-spoon sampling and analyzed by EPA approved laboratory methods to validate the fluorescence sensor. The LIF sensor showed 96% agreement with the laboratory analysis on a detect/non- detect basis. Quantitative comparison of the fluorescence and analytical data show a strong correlation, suggesting that the fluorescence sensor may be capable of quantifying the contaminant concentration given a small number of soil samples for calibration.

Success in field measurements requires both appropriate instrumentation and appropriate data acquisition and treatment strategies. Recent advances in instrumentation have improved the utility of Raman spectroscopy for field measurements. This presentation focuses on data acquisition and treatment strategies. We have built into our measurement systems both hardware and software to provide automated wavenumber and intensity calibration and correction. Field measurements demand better wavenumber accuracy than is generally appreciated. In our approach, wavenumber calibration is based on atomic line spectra. Intensity axis calibration requires correction for pixel-to-pixel and wavelength-dependent sensitivity variations of the detector and wavelength- and time-dependent throughput variations of the probe and spectrograph optics. The data needed for these corrections are obtained by measurement with a calibrated white light source and with a standard sample. This presentation describes reference materials and how the calibration and corrections are affected.

Fluorescence spectroscopy has been used extensively to solve environmental problems (including biological, water quality, separation and etc.). Despite its numerous applications, long wavelength, near- infrared (NIR) fluorescence has been the subject of very few studies. This wavelength region is advantageous, if we wish to minimize the effect of background interference. Lowering the background interference is especially advantageous in environmental monitoring applications where very little or no preseparation is necessary to achieve selective measurements. The applications of NIR absorbing fluorophores which usually have high molar absorptivities and good quantum yields can be especially advantageous when laser diodes are employed as the excitation source. This paper will focus on several general practical analytical applications of NIR fluorescence spectroscopy for solving environmental related analytical problems, including but not limited to: use of NIR fluorophores as labels (in conjunction with immunosensor technology) and the use of NIR chromophores as direct probes (pH, metal ion, etc.). Additionally the use of laser diodes and semiconductor detectors (silicon photodiodes and avalanche photodiodes) as light sources and detectors will be discussed.

Simple colorimetric tests have been developed to screen for the presence of TNT, TNB, DNT, DNB, tetryl, RDX, HMX, nitroglycerine (NG), PETN, nitrocellulose (NC), nitroguanidine (NQ), picric acid and ammonium picrate in soil. Soils are extracted by manual shaking with acetone. For the nitroaromatics, the extracts are reacted with potassium hydroxide and sodium sulfite to form their colored Janowsky complexes. For RDX, HMX, NG, PETN, NC and NQ, extracts are passed through an anion exchange resin to remove nitrate, and then acidified with acetic acid; the nitramines and nitrate esters are reduced with zinc to form nitrous acid. The nitrous acid is detected by the Griess reaction using a Hach Nitriver 3 powder pillow, which produces a highly colored azo dye. Detection of these analytes can be obtained visually and concentrations estimated from absorbance measurements at 540 nm for TNT, TNB and tetryl, 570 nm for DNTs and DNB, and at 510 nm for RDX, HMX, NG, PETN, NC and NQ. For picric acid/ammonium picrate, the acetone extract is passed through a basic ion-exchange column that retains picrate ion. The column is rinsed with methanol to elute interferences, and the picrate is desorbed with acetone containing several drops of sulfuric acid. The extract is diluted with deionized water, and the concentration of picrate is obtained from the absorbance at 400 nm. Detection limits are about 1 (mu) g/g for all analytes except NG, NC and NQ, which are slightly higher. Results from field screening at a number of sites have been correlated with laboratory analyses for TNT and RDX. The results indicate that the field screening methods do not suffer from false negatives and the rate of false positives is low. Concentration estimates from field screening compared favorably with results from the standard laboratory methods.

The PetroSense^R CMS 5000 is a continuous monitoring system for the monitoring of total hydrocarbons. The PetroSense^R CMS 5000 is capable of providing real time, in situ monitoring of hydrocarbons in water, vapor, soil and the water/vapor interface. This makes it ideal for tracking the movement of hydrocarbons through the soil and water, i.e., monitoring the effects of remediation of polluted sites as well as leak detection from above and below ground storage tanks.

The U.S. Army manufactures munitions at facilities throughout the United States. Many of these facilities are contaminated with residues of explosives from production, disposal of off- specification, and out-of-data munitions. The first step in remediating these sites is careful characterization. Currently sites are being characterized using a combination of on-site field screening and off-site laboratory analysis. Most of the contamination is associated with TNT (2,4,6-trinitrotoluene) and RDX (hexahydro-1,3,5-tri-nitro-1,3,5-triazine) and their manufacturing impurities and environmental transformation products. Both colorimetric and enzyme immunoassay-based field screening methods have been used successfully for on-site characterization. These methods have similar detection capabilities but differ in their selectivity. Although field screening is very cost-effective, laboratory analysis is still required to fully characterize a site. Laboratory analysis for explosives residues in the United States is generally conducted using high-performance liquid chromatography equipped with a UV detector. Air-dried soils are extracted with acetonitrile in an ultrasonic bath. Water is analyzed directly if detection limits in the range of 10 - 20 (mu) g/L are acceptable, or preconcentrated using either salting-out solvent extraction with acetonitrile or solid phase extraction.

New approaches are presented for the extraction and analysis of explosives and related compounds in aqueous samples from former ammunition production sites. Quantitative extraction of nitroaromatics but also of the polar nitramines such as RDX and HMX is achieved by solid phase extraction with styrene-divinylbenzene polymers (Lichrolut EN). Proton nuclear magnetic resonance (¹H-NMR) has been used to identify and quantify unknowns in ammunition waste water. Finally, automated multiple development (AMD) high performance thin layer chromatography was applied for the first time to the analysis of this compound class.

In Germany, many abandoned sites are situated where during the world wars explosives (nitroaromatic compounds, nitramines and nitrate esters) were produced. They contaminate upper soils and ground/drinking water. Nitro- and aminoaromatic compounds have not only a potential for methemoglobin formation but also a carcinogenic one. Since 1992, 35 compounds have been evaluated toxicologically by our institute. We used an evaluation pattern weighting not only positive/doubtful/negative test results, but also data gaps, and which results in a standardized evaluation number (EN). Four compounds received an EN on a reliable data basis and 11 on a provisional one. For the other 20 compounds, mainly nitroxylenes and some dinitrotoluenes, the data basis was missing almost completely. A subset of 11 structures was classified, either for precautionary aspects or positive in vivo data, as probable human carcinogens, whereas for 7 not only an EN, but also a tolerable body dose (TDI) could be proposed. EN based guide values between 0,10 (mu) g/L (precautionary value) and 10 (mu) g/L (sum value) were derived for drinking water. In soils, a precautionary guide value of 1 mg/kg (sum value: 5 mg/kg) seems protective for all exposure scenarios without plant transfer, whereas TDI-based values are much higher.

The anaerobic sequencing batch biofilm reactor (AnSBBR) was used to select for, enrich, and modify the physiological state of one or more of the many possible microbial consortia that can participate in the reductive dechlorination of perchloroethylene (PCE). The AnSBBRs used in these studies are periodically operated, up-flow, packed column, biofilm reactors. Initial AnSBBR studies demonstrated that PCE, fed at 8 mg/L, could be reductively dechlorinated to cis-1,2-dichloroethylene (cDCE) using either methanol or acetate as a co- substrate. PCE fed at over 160 mg/L could be completely reductively dechlorinated to ethylene when acetate was used as the co-substrate and methanol as the solvent for PCE addition. These studies support the hypothesis that the extent of reductive dechlorination is determined by environmental parameters which effect the physiological state of the bacterial consortium.

A survey with appropriate references about monitoring of radioactivities encountered in the environment is presented. The first part is concerned with different sources of cosmogonic and terrestrial radionuclides on one side and, on the other, with radionuclides released into the environment by activities of people. Afterwards, attention is focused on the physical, chemical, and technical aspects of advanced measuring techniques including sample treatments.

The U.S. Department of Energy, Nevada Operations Office, Underground Test Area Operable Unit (UGTA) is drilling deep (greater than 1500 m) monitoring wells that penetrate both unsaturated (vadose) and saturated zones potentially contaminated by sub-surface nuclear weapons testing at the Nevada Test Site, Nye County, Nevada. Drill site radiological monitoring returns data on drilling effluents to make informed management decisions concerning fluid management. Because of rapid turn-around required for on-site monitoring, a representative sample will be analyzed simultaneously for alpha, beta and gamma emitters by instrumentation deployed on-site. For the purposes of field survey, accurate and precise data is returned, in many cases, with minimal sample treatment. A 30% efficient high purity germanium detector and a discriminating liquid scintillation detector are being evaluated for gamma and alpha/beta monitoring respectively. Implementation of these detector systems complements a successful on-site tritium monitoring program. Residual radioactivity associated with underground nuclear tests include tritium, activation products, fission products and actinides. Pulse shape discrimination (PSD) is used in alpha/beta liquid scintillation counting and is a function of the time distribution of photon emission. In particular, we hope to measure ²⁴¹Am produced from ²⁴¹Pu by beta decay. Because ²⁴¹Pu is depleted in fissile bomb fuels, maximum PSD resolution will be required. The high purity germanium detector employs a multichannel analyzer to count gamma emitting radionuclides; we designate specific window configurations to selectively monitor diagnostic fission product radionuclides (i.e., ¹³⁷Cs).

In the underground laboratory 'Felsenkeller' in Dresden a new iron shielded counting room is installed. In the paper the laboratory is described and examples of application of low-level counting techniques are presented. Long-lived radionuclides in low-level wastes from a power station are corrosion products, fission products, and actinides. They have been radiochemically separated and measured by alpha, beta, and gamma spectrometry. Natural radionuclides in soil samples, water and plants from the vicinity of an uranium mining plant are measured by gamma and by alpha spectrometry. Geochemical and technological processes cause important changes of the radioactive equilibrium, for example in the activity ratio of ²²³Ra and ²²⁶Ra.

The paper summarizes the results of radon concentration and gamma dose rate monitoring in the carriages and in some stations of the Prague Metro network. The measurements reveal that both radon levels and external photon doses in the Metro are relatively low in comparison to those normally encountered in dwellings in the Prague region. On average, the radon concentrations in air inside the carriages have been found to be about 11 - 12 Bq m^-3 while the levels in most stations reach values between 10 and 15 Bq m^-3. Also the gamma dose rates in the stations show lower values which, in general, were in the range of 60 - 110 nGy h^-1 depending on the depth of the stations and the materials used in their interiors. As to the trains, the average dose rate of passengers as well as train drivers was observed to be below 50 nGy h^-1.

In Germany soil remediation technologies are looking back to a development of 10 to 15 years. In the eighties ground examination standards and waste limits values have been defined which are forming the basis of all remediation methods. Today the classical cleaning technologies like soil washing and activated coal adsorption have just reached their physical limits. Additional technical proceedings have to improve cleaning efficiency and decomposition of waste.

The contamination of soil by aromatic mineral hydrocarbons (MHC) (e.g., gasoline, oil, etc.) has become a severe environmental problem because not only men, animals, and plants are threatened but also the water and air. With the unification of Germany a great number of suspected contaminated sites in the new countries were registered. An estimation of the German Federal Ministry of Environment (BMU) counts 180,000 areas contaminated with different pollutants, 55,000 are situated in the former GDR. On military settlements for example more than fifty percent of the chemicals are MHCs. Hence one can get an idea of the importance of soil pollution by hydrocarbons. Other zones contaminated due to carelessness or accidents are civil petrolstations, airports, refineries, pipelines, and traffic disasters. At the present time for most of these areas the contamination is assumed due to recent use. Due to the large extension of the problem an estimation and evaluation of the potential hazard for the environment is difficult and expensive to perform. In the case of an actual endangering the total area must be mapped in detail resulting in increasing costs for the owner. Nevertheless it is necessary to find reliable timesaving areal mapping and monitoring methods. One opportunity presented in this paper is the application of remote sensing by laser induced fluorescence from an airborne platform. It promises to fulfill these requirements in a sufficiently fast manner with very high spatial resolution. The access to the pollutant detection is the specific laser induced fluorescence emitted by the MHC (finger print). The present work shows the requirements for a helicopterborne lidar system for MHC mapping and how the detected signals are to be evaluated and interpreted.

Results of the UV absorption properties of nitrate in waters and the effects of potential inorganic and organic species on these properties are presented. The attenuation of the water Raman and Rayleigh back-scattered light of appropriate wavelengths by nitrate distributed along the probed water column is correlated with nitrate concentration. An analysis of the results in terms of an extended source in the water column and integrated absorption (over a certain depth) is presented. The feasibility of using a differential absorption and scattering technique utilizing water Raman and Rayleigh back scattered signals without any optical contact with cell walls is examined, so that the problem of cell fouling in conventional absorption measurements is avoided.

We report a development of analytical techniques and a portable high selective analyzer for measuring mercury content in the atmosphere, water, soil and biological objects to use them in ecological monitoring and to control technological processes with mercury and the compounds thereof. Provision of mercury monitoring is made from background to maximum permissible concentration (MPC).

From the fluorescence analysis of PAC-doped model oils on alumina, quartz sand, and soil surfaces LIF intensity/concentration-relationships (calibration curves) were obtained. It was found that LIF measurements directly from soil surfaces allow the in-situ analysis of PAC contaminations in environmentally relevant concentration ranges. However, the LIF signals measured cannot directly be related to photophysical parameters of the PAC in solution. Also reported are results of preliminary investigations of the long-term behavior and the depth profile of perylene or fluoranthene LIF signals from surfaces reflecting mass transport and sorption processes.

Dual laser flow cytometry can be used for determining phytoplankton populations in lakes and lowland rivers and streams. Apart from answering basic limnological questions such as the time course of algal blooms or the annual succession of phytoplankton composition further investigations can be made for estimating the integrity of a phytoplankton community using biomass distribution spectra. Thus anthropogenic influence such as eutrophication, acidification or effects of xenobiotica can be monitored. Dual laser flow cytometry with excitation wavelengths of 458 and 528 nm was used to measure photosynthesis pigment fluorescence (chlorophyll a (CHLa), Em greater than 665 nm) and phycoerythrin (PE, Em 575 nm) and cell density of phytoplankton organisms in water samples. CHLa is excited directly by 458 nm and by energy transfer from carotenoids (Ex 528 nm). The ratio of the two fluorescence parameters (CFR) allows users to identify pigment groups in the phytoplankton population (chlorophytes and euglenophytes from chrysophytes, diatoms and dinophytes). PE- containing cyanophytes and cryptophytes can be detected by their PE fluorescence (Ex 528 nm). As a result of preliminary studies for preparing biomass spectra of phytoplankton communities measurements of protein content by staining with fluorescein isothiocyanate (FITC, Ex 488 nm, Em 530 nm) are also shown.

The PetroSense^R CMS 5000 is a continuous monitoring system for the monitoring of total hydrocarbons. It is capable of providing real time, in-situ monitoring of hydrocarbons in water, vapor, soil, and the water/vapor interface. To monitor leaks from storage tanks the PetroSense^R probes have to be placed under or around these tanks. In this paper the performance of the CMS 5000 probes under simulated field conditions is described along with data from a field installation.

A fractal analysis is presented for the binding of pyrene in solution to beta-cyclodextrin attached to a fiberoptic chemical sensor. The specific (k₁) and the non-specific binding rate (k_ns) coefficients and the fractal dimension, D_f (specific binding case only) both tend to increase as the pyrene concentration in solution increases from 12.4 to 124 ng/mL. Predictive relations for the binding rate coefficient (specific as well as non-specific binding) and for D_f (specific binding case only) as a function of pyrene concentration are provided. These relations fit the calculated k₁ and D_f values in the pyrene concentration range reasonably well. The fractal analysis provides novel physical insights into the reactions occurring on the fiberoptic chemical surface and should assist in the design of fiberoptic chemical sensors.

Problems of measurement of the radiation dose level and determining the position of the ⁶⁰Co radiation source rods are discussed. The continuous gamma ray source ⁶⁰Co is used for various scientific and industrial, food and medical, irradiation applications with doses up to 10⁴ Gy. For a radiation sensor the PCS optical fiber could be used. By radiation effects testing PCS fiber is found to have adequate sensitivity in the visible range up to 1.47 multiplied by 10^-1 dB/kmGy at high exposure, up to 10³ Gy ⁶⁰Co ionizing source irradiation. The position of the source rods is determined relative to the safety position, by the sensor linked with source position using a mechanical transmission system. The digital position sensor based on the optoelectronic impulse source is developed, with accuracy plus or minus 1 mm for the whole vertical position change of the source and great exploitation resistance particularly to vibrations.

The microscopic movement of contaminants in a porous medium has been simulated in an experiment. The approach has been to study the microscale transport processes using a novel nonintrusive fluorescence imaging technique developed in our laboratories. The system studied consists of a packed porous column with a refractive index-matched fluid seeded with fluorescent tracer particles (for flow measurements) or an organic dye (for contaminant concentration measurements). Microscopic measurements of contaminant concentration, contaminant velocity, and pore geometry were obtained in a full three-dimensional volume of the test section at a good accuracy and a high resolution. Three dimensional plots of these measurements show the complex geometry of the porous medium. It is also seen that near the contaminant front there is a significant correlation between the flow and the contaminant concentration. The goal is to use these and future results toward better understanding of contaminant flow and transport through natural porous media.

This report deals with geology-geophysical investigations of the Earth surface by means of aerospace remote sensing, especially by methods using polarization parameters of the light. The possibility to detect sources of ionizing radiation, spreading on the Earth surface and containing any kind of emitted particles (or their combinations), by means of a special technique is shown. Physical argumentation of ionizing radiation influence on parameters of the upper soil layer and certain quantitative approximations are considered. The opportunities to detect the influence of the discussed sources by means of remote optical polarization mapping of soils are demonstrated. This technique could be used in a survey of the bare soil, i.e., the soil without vegetation.

This work involves the design and development of species specific gene (DNA) probes designed to detect Pseudomonas species. A non radioactive detection system for DNA was designed to detect the presence of these microbes in environmental samples for biomonitoring applications. The details of the methodology and their applicability for various environmental analyses is discussed below.

Polycyclic aromatic hydrocarbons (PAH) contamination is a considerable problem at various hazardous waste sites. Sources of PAH contamination include incomplete combustion processes, wood preservatives, and the fuel industry. The development of rapid, cost-effective field screening techniques to qualitate or quantitate potential PAH contamination could result in improved remediation efficiency. We have recently developed a portable spectrofluorometer for screening potential PAH contaminants at field sites using the synchronous fluorescence approach. Synchronous fluorescence differs from the more conventional excitation or emission fluorescence as both monochromators are scanned simultaneously with a constant wavelength offset ((Delta) (lambda) ) between the two. The portable spectrofluorometer was developed at Oak Ridge National Laboratory (ORNL) for the U.S. Environmental Protection Agency (EPA), National Exposure Research Laboratory, and recently field tested at the American Creosote Works Superfund Site in Jackson, Tennessee. In this paper, the portable spectrofluorometer was used to field screen several contaminated soil areas located at the Morristown Industrial Site in Morristown, Tennessee using the synchronous fluorescence technique. An attempt to quantify PAH contamination was performed using the NIST 1647a priority pollutant standard to generate a calibration curve. Representative samples were subsequently related to the results obtained from standard laboratory measurements.

A laser-based synchronous scanning fluorimeter has been developed for the detection of polycyclic aromatic hydrocarbons (PAHs). Although extensive sample cleanup and separation are usually required, fluorescence has long been used for the determination of PAHs. The amount of sample pre-treatment can often be reduced when synchronous fluorescence (SF) is used, and the sensitivity of SF can be increased by the high power and narrow profile of a laser source. A small, portable, pulsed dye laser was used in this study. The instrument and its application to the determination of the carcinogen, benzo(a)pyrene, are described.

Seepage water of landfills, where toxic waste is deposited, has high concentrations of chlorinated phenols (CP), polychlorinated biphenyls (PCB), and polycyclic aromatic hydrocarbons (PAH). The concentrations of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are usually found at ppq-level. Typical purification methods based on physical techniques produce highly contaminated residues, which have to be removed by combustion or deposition in a landfill. An alternative way is to destruct these contaminants by biological and chemical treatment. The behavior of the trace contaminants during UV/ozone treatment is described. Results show no significant effect for PCB and PCDD/PCDF. The CP and PAH were mostly reduced by UV/ozone treatment to a degradation ratio greater than 90%. An influence of the pH value on the UV/ozone treatment of seepage water could not be detected. A further experiment showed the degradability of PCDD/PCDF in pure water solution. To reach better results for the degradation of organic trace contaminants the seepage water first can be treated with biological methods. Thus the high TOC-concentration of 3 g/l is reduced to 50 - 70%. A combination of biological and oxidative techniques diminishes the treatment costs and better exploitation of the oxidants is reached. Because of high light absorbance of the seepage water between 200 nm and 300 nm we developed a falling-film- photo-reactor to ensure, that every volume of the solution is exposed to UV-radiation.

Groundwater contamination and PAH-removal with a special water purification facility were monitored over several months by a PAH-immunoassay as well as by HPLC. In the enzyme- linked immunosorbent assay (ELISA) a polyclonal rabbit antiserum was applied. As test format an indirect competitive microtiter plate assay was used. The water samples could be directly measured without any extraction and purification steps. With the ELISA, the limit value for the sum of PAHs of 0.2 ppb as set by the German Drinking Water Act was certainly reached. Including 114 samples no false negative (defined as a measured concentration below 0.2 ppb) but 20 (17.5%) false positive (defined as a measured concentration above 0.2 ppb) samples were found with the immunoassay. Supposing the immunochemical results to be approximate values of the total PAH concentration then these data correlate very well (r equals 0.82, n equals 114) with the sum of the 16 EPA PAHs as measured by HPLC in this study. Therefore, the ELISA could be used as a rapid screening technique to diminish the sample number for HPLC.

Trace amounts of radiotoxic elements are determined by means of resonance ionization mass spectroscopy (RIMS). An extremely high element-selectivity is obtained via resonant multiphoton excitation of the atoms leading to an autoionizing state. The ions produced are mass-selectively detected. This leads to good isotope-selectivity and efficient background suppression. These properties allow a simplification of the chemical separation. With RIMS the detection limit does not depend on half-life or decay mode of the determined isotopes as it is the case for radiometric methods. Two experimental approaches for trace detection of plutonium are described. An overall detection efficiency of 3 multiplied by 10^-5 has been determined yielding a detection limit of 1 multiplied by 10⁶ atoms of ²³⁹Pu. The practicability of those methods was demonstrated with environmental samples.

A new sensor design for remote surface-enhanced Raman scattering (SERS) measurements has been developed for environmental applications. The design features the modification of an optical fiber using layers of alumina microparticles and silver coatings for inducing the SERS effect at the sensing probe. A single fiber caries both the laser excitation and the SERS signal radiation, keeping optical parameters at the remote tip simple and consistent. The small tip size achievable with this configuration also demonstrates potential of this new design as a microsensor for in-situ measurement in microenvironments. Details of sensor tip fabrication and optical system design are described. SERS spectra of aqueous environmental samples acquired in-situ using the SERS sensor are also presented to illustrate the effectiveness of the SERS sensor.

The analyses of air quality using chromatography or optical methods are very accurate but rather expensive. A cheaper solution consists of using solid state chemical sensors in easy-to- use portable and rugged equipment or distributed systems to achieve a continuous monitoring of pollution. Nevertheless it is difficult to discriminate among a set of gases because these sensors have poor selectivity. Measurements on thick-film tin oxide gas sensors have shown that their conductance transient, when they are exposed to a step change in gas concentration, is diffusion limited. The analysis and characterization of this transient enables a rise time to be obtained, which is independent of the final conductance value and depends, among other parameters, on the diffusion coefficient of gases into the porous structure of the sensor. This parameter is easily measurable and gives useful information for gas/vapor recognition. In particular in this work we have shown that it is possible to discriminate among a set of three volatile organic compounds VOCs (benzene, toluene and o-xylene) using a commercial Taguchi Inc. semiconductor gas sensor.

Flow cytometry in combination with ribosomal RNA (rRNA) based fluorescence in situ hybridization is a new technique for the analysis of microbial communities. Oligonucleotide probes directed against ribosomal RNA allow the identification of species or groups of micro- organisms. Combined with flow cytometry, up to several thousand cells per second can be classified. In addition to the identification and specific enumeration of micro-organisms, further information on the distribution of cell size, DNA and ribosome content -- and therefore an assessment of activity -- within the entire community or subpopulations can be obtained. This technique is much more accurate, informative, and rapid than classical culture-dependent methods. Data of activated sludge samples hybridized with fluorescein labeled oligonucleotides and counterstained with the DNA-specific dye Hoechst 33342 are presented as examples for its applicability to complex microbial communities.

We report about light-emitting diodes (LEDs) and photodiodes (PDs) for the spectral ranges 1.8 - 2.4 micrometer and 2.9 - 4.7 micrometer based on multicomponent III-V alloys (GaInAsSb/GaAlAsSb, InAsSb/InAsSbP). High-efficiency small-dimension optoelectronic devices were applied to the design of novel set gas and moisture analyzers. Progress in development of different kinds of experimental models of the analyzers is demonstrated. Such portable sensors can be used for ecological monitoring, detecting industrial pollutants, and for various medical applications.

The removal of xenobiotic compounds, such as chlorophenols and pesticides, from municipal and industrial wastewaters is an important task because of the toxicity and the tendency to bioaccumulation of these compounds. Among the several methods proposed, photodegradation catalyzed by suspended inorganic semiconductors (i.e. TiO₂) has lately received wide attention because this process is fast, leads to non-toxic final products and shows a high degradation efficiency. In this work, the results obtained in the photodegradation of monochlorophenols using a new catalyst, made of TiO₂ and polyaniline both immobilized on a polyvinylchloride (PVC) membrane, in presence (and in absence) of an enzyme are presented. Different enzymes have been tested by adding 5, 10 or 15 U/mL to 50 mL of aqueous solution (1 multiplied by 10^-4 mol/L) of o-chloro-phenol containing the catalytic membrane. The samples were irradiated using a QUV panel accelerated weathering tester, which simulates very well the solar radiation up to lambda equals 400 nm and HPLC was used to measure the variation of the compound's concentration with the time. While some enzymes (i.e., peroxidase) do not improve the photodegradation process since they do not survive under the irradiation conditions used, some of them show marked effect both in terms of rate degradation and time required to reach the total degradation of the compound examined. For example, the addition of Laccase reduces the 100% degradation time from 35 hrs to about 20 hrs. Attempts to immobilize the enzyme on the catalytic membrane (by adsorption) have been carried out and the performance of the catalyst with non-immobilized and immobilized enzyme has been studied.

The application of new pesticides requires careful monitoring of their distribution in the environment. The effect of the soil microflora on the stability of the [¹⁴C]- labelled juvenoid hormone analogue W-328 was estimated. The micro-organisms from two different soil samples were isolated and tested for their ability to decompose W-328. One bacterial strain, yeast and mold isolates, exhibited the degradation activity. The growth characteristics such as pH and temperature optima were determined. The degradation products were estimated using HPLC.

Sandia National Laboratories has developed sensors allowing real-time, continuous measurement of hydrogeologic parameters for use in contaminant transport modeling, risk assessments, and the optimization of remedial alternatives (e.g., soil venting, bioremediation). These sensor packages have been engineered into a cone penetrometer push technology, in addition to their stand-alone deployment. The sensor packages include a time domain reflectometry (TDR) sensor to quantify volumetric soil moisture content and a fiber optic relative humidity (RH) sensor to quantify capillary pore pressure in unsaturated soils. Results indicate that TDR probes having optimal specifications yield measurements representative of the formation. TDR probes show better accuracy than neutron and capacitance probes. RH sensors responded quickly in the laboratory, but redesign will be necessary to make the housing suitable for 'real-time' cone penetrometer applications. Sandia deployed the TDR and RH probes along with geotechnical sensors on a cone penetrometer rig. Data allowed three- dimensional analysis of lithologic control of soil water migration at a level of detail greater than possible using conventional methods. In addition, the TDR design has been employed in a down-hole logging configuration for routine monitoring in access tubes, as a non-nuclear alternative to a neutron probe. The cone penetrometer with the TDR probe represents a significant technological advance in site assessment capabilities.