Proceedings Volume 1716

International Conference on Monitoring of Toxic Chemicals and Biomarkers

Tuan Vo-Dinh, Karl Cammann
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Proceedings Volume 1716

International Conference on Monitoring of Toxic Chemicals and Biomarkers

Tuan Vo-Dinh, Karl Cammann
View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 9 March 1993
Contents: 13 Sessions, 56 Papers, 0 Presentations
Conference: Environmental Sensing '92 1992
Volume Number: 1716

Table of Contents

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Table of Contents

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  • Detection of Metals and Organics
  • Environmental Biomonitors Based on Immunological Principles
  • Analytical Techniques and Instrumentation
  • Air, Water, and Soil Monitoring
  • Biosensors for Environmental Monitoring
  • Monitoring Environmental Biomarkers
  • Biomarkers and Molecular Epidemiology
  • Intracellular Monitoring of Chemical Xenobiotics
  • Chemical Sensors I
  • Chemical Sensors II
  • Poster Session
  • Field Techniques
  • Field Exposure Studies
  • Poster Session
  • Chemical Sensors II
  • Field Exposure Studies
  • Poster Session
  • Biomarkers and Molecular Epidemiology
  • Analytical Techniques and Instrumentation
  • Poster Session
  • Biomarkers and Molecular Epidemiology
  • Air, Water, and Soil Monitoring
  • Analytical Techniques and Instrumentation
Detection of Metals and Organics
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Laser-induced breakdown spectroscopy for detection of heavy metals in environmental samples
Richard W. Wisbrun, Israel Schechter, Reinhard Niessner, et al.
The application of LIBS technology as a sensor for heavy metals in solid environmental samples has been studied. This specific application introduces some new problems in the LIBS analysis. Some of them are related to the particular distribution of contaminants in the grained samples. Other problems are related to mechanical properties of the samples and to general matrix effects, like the water and organic fibers content of the sample. An attempt has been made to optimize the experimental set-up for the various involved parameters. The understanding of these factors has enabled the adjustment of the technique to the substrates of interest. The special importance of the grain size and of the laser-induced aerosol production is pointed out. Calibration plots for the analysis of heavy metals in diverse sand and soil samples have been carried out. The detection limits are shown to be usually below the recent regulation restricted concentrations.
Substrate effect on the enhanced biodegradation of carbon tetrachloride
Shian Chee Wu, Rueyan Doong
The effects of different substrates on the biotransformation of heavily chlorinated hydrocarbons under anaerobic conditions were investigated to evaluate the feasibility of in-situ bioremediation of the contaminated groundwaters by amending different substrates. The substrate-fed batches were anaerobically incubated with the addition of either acetate, glucose, methanol, or dissolved organic matter (DOM) with concentrations ranging from 10 to 30 mg/L. Experimental results demonstrated that the effect of the substrates on the dechlorination of the compounds varied. The removal efficiency was observed greatest for glucose- then methanol- and acetate-fed batches and least for DOM-fed batches. The sequence of the enhancement efficiency is consistent with the sequence of the reducing potentials of these substrates. Changing the substrate concentration could vary the dechlorination capability of the system. The viable counts of microorganisms determined by the direct epifluorescence counting technique showed that the batches with higher concentration of the supplemental substrate produced higher bacterial cell numbers. Moreover, from microscopic observations, different compositions of bacterial population were found. Small-sized bacteria with spheric shape were observed when culture bottles were amended with either acetate or DOM, whereas large-sized bacteria with rod-shape were predominant for bottles amended with glucose. Also, higher DNA contents were demonstrated for glucose-fed batches.
Environmental Biomonitors Based on Immunological Principles
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Monoclonal antibody-based enzyme immunoassays for the sensitive detection of s-triazines in water
Bertold Hock, Thomas Giersch, Karl-Josef Kramer
Immunoassays in pesticide residue analysis significantly profit from the monoclonal antibody (mAb) technology because a sufficient supply of standardized antibodies can be provided. For the production of atrazine-specific mAbs hybridoma cells were produced by fusion of mouse myeloma cells and spleen cells from mice which were immunized with 4-chloro-6-ethylamino- 1,3,5-triazine-2-(6-aminohexanoic acid) coupled to keyhole limped hemocyanin. After screening with a competitive enzyme immunoassay (EIA) a mAb with high binding affinity towards atrazine was selected. A sensitive EIA was developed detecting atrazine with a range from 0.05 to 1 (mu) g/l with a test midpoint of 0.1 (mu) g/l. The mAb cross-reacts predominantly with propazine (136%). Since this herbicide is not used in most European countries, the test allows a rapid and inexpensive screening for atrazine in the ppt range. Another EIA has been constructed for the detection of terbuthylazine. The limiting factor in EIA development is the screening for cell lines secreting mAbs with high affinity and selectivity towards the analyte. Super paramagnetic beads being coated with suitable immonoconjugates are shown to bind to hybridomas presenting hapten-specific receptors on their surface. Hybridomas secreting hapten-specific mAbs can be removed by a magnet and be cloned subsequently by standard procedures. A considerable demand of mAbs is expected in the future due to new emerging techniques such as immunosensors.
Laser-based fiberoptic immunosensors
Tuan Vo-Dinh, Jean Pierre Alarie, Michael J. Sepaniak
This paper provides a brief overview of the development and application of fiber-optic antibody-based fluoroimmunosensors (FIS) for measuring environmental pollutants and related biomarkers of human exposure and health effects. The FIS combines the excellent specificity of the antigen/antibody reaction, the high sensitivity of laser excitation, and the versatility of fiber-optics technology. Various types of FIS devices were also used to detect toxic chemicals (such as benzo-a-pyrene) and related DNA adducts (e.g., benzo(a)pyrene tetrol).
Development of an enzyme immunoassay for the determination of 2,4,6-trinitrotoluene: probing the influences of humic acids
Claudia Keuchel, Ludwig Weil, Reinhard Niessner
A new enzyme immunoassay is described which can be used for the determination of the explosive 2,4,6-trinitrotoluene in water. The assay has a detection limit of 30 ng/l. The evaluation of cross-reactivities shows that the used antibody has a high selectivity for the trinitrophenyl moiety. Since humic substances, commonly occurring in natural waters, can interact with antibodies, the obtained results can be false positive. To reduce the negative influence of the humic substances the usually performed ELISA protocol has been modified by adding a solution of bovine serum albumin (0.5% in PBS) after the coating step.
Analytical Techniques and Instrumentation
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Flue gas analysis with a multicomponent IR-spectrometer
Annika Johansson, Christer Brunstrom
The performance of a multi-component IR-spectrometer (Perkin-Elmer, mode. MCS 100) has been evaluated with regard to the influence of possible interferences from the gaseous compounds present in a flue gas. The spectrometer is configurated for measurement of NO, NO2, CO, CO2, N2O, NH3 and H2O. A theoretical examination of the absorption spectra of possible interfering hydrocarbons has been carried out together with a theoretical estimation of the errors introduced during the compensation for interferences due to incorrectly measured absorbances. The accuracy of the automatic compensation routines for interferences used by the spectrometer has been investigated by laboratory test runs including potential interferences from components not measured by the analyzer. The response time of ammonia has been studied in the laboratory and during field measurements.
Optical fiber sensor systems for forest protection in Canada
Andrzej W. Domanski, Tomasz R. Wolinski, Artur Dybko, et al.
Forest damages in Canada have been observed to occur since the mid-1970's. Current hypotheses that attempt to explain forest declines implicate the effects of acid deposition, excess sulfur and nitrogen deposition, and elevated concentration of ozone and carbon dioxide on forest soils and nutrition as major contributors. Forest protection requires information about the pH of precipitation and aquatic ground water/soil systems along with the characterization of chemical toxicants distribution in the forest environment. Present analytical techniques for toxic chemical compounds are not well suited for field measurements. Current methods require collection of samples in the field and subsequent analysis in the laboratory. The paper discusses the possibility of applying fiber optic sensing networks for constant monitoring of pH and input/output balance of forest ecosystems to overcome most of the limitations of current methods for characterizing the distribution of chemical toxicants in the forest environment. The idea of such networks is based on sensors which couple fluorescence measurement with optical fibers offering not only a good precision and reliability but direct compatibility with fiber optic telemetry, optical data transmission systems, and optical multiplexing technology.
Use of combined GC/CIMS-EIMS-FTIR for the automated analysis of complex mixtures
Roger J. Leibrand
Solid industrial waste dumps, being an anthropogenic part of the vadose zone, are potential non-point sources of ground water contamination. The early warning provided from qualitative and quantitative information on contaminant migration within a dump is an essential element in monitoring and screening sites for hazardous waste deposition that prevents degradation of recoverable ground water resources and permits to avoid either false positive or false negative errors in evaluation and prediction of the extent of environmental hazards. Multilevel sampling of dump and vadose zone cross sections in the defined points of known waste age and dump construction delivers direct information on vertical distribution of contaminants as a function of time, that is a resultant of a dump and vadose zone hydrogeology, as well as of the mechanism and dynamics of constituent release, interaction and biogeochemical transformation in pore solution. The current presentation describes a procedure for multilevel sampling, pore solution extraction and examination and provides data (vertical profiles of contaminant distribution from a selected landfill site) that exemplify necessity of dump/vadose zone multilevel sampling for correct assessment of contaminants migration rate, understanding processes and conditions affecting contaminant transport, and enhancement of remedial response measures.
Air, Water, and Soil Monitoring
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Monitoring of industrially relevant organic gases by CO2 laser radiation
Michael Fiedler, Robert Lange
Literature data concerning organic compounds of industrial importance have been analyzed in order to estimate the performance of CO2 laser based detection of atmospheric trace gases with special respect to remote sensing.
Air monitoring in chemical plants with emphasis on sulphuric acid aerosol using a specially designed monitor
Cor de Ruiter, Rene W.M. Jansen, Theo H. Visser, et al.
A method for continuous air monitoring of sulphuric acid at workplaces is described. The monitor is equipped with a sampling inlet specially designed for sulphuric acid aerosol. In this inlet the aspirated air is wetted with pure water and on-line transferred to a gas/liquid separator. After separation of the phases, the aqueous phase is directed through a conductivity detector. The monitor has been used in a yarn production plant in which light concentrations of sulphuric acid have been used. Application of this monitor gave insight into the efficiency of the ventilation systems under high spinning speed conditions.
Laser photoacoustic trace detection of C2H4 revealing adverse environmental effects of atmospheric pollution on plant material
Frans J. M. Harren, Luciana Petruzzelli
The photoacoustic detection method for trace gases in the atmosphere is well developed towards very low limits of detection, in the last years. Due to the combination of a sensitive photoacoustic cell placed intracavity in an infrared CO2 laser we were able to detect C2H4 at ultralow (< 1:1011) concentrations within 10 seconds, C2H4 in a plant hormone which seems to play an important role throughout all the life stages of a plant, including seed germination. In addition, various types of stress have been reported to promote ethylene production from different plant tissues. As part of our ongoing research on the role of ethylene in seed germination, we have compared our laser photoacoustic set-up to a gaschromatograph for measuring C2H4 produced by germinating Pisum sativum L. seeds within the first days of imbibition. C2H4 evolution by intact seeds shows a maximum at about 25 hours of germination. Thereafter, the rate of ethylene measured by gaschromatograph continues to decrease while that measured by the laser-driven photoacoustic system shows further increases. Most of the ethylene produced by seeds is found in isolated embryonic axes. The fumigation with ozone affects the growth of seedlings and their ethylene evolution.
Development of a long-path Fourier transform infrared instrument for measurements of diffuse VOC emissions from the automobile industry
Hakan Axelsson, Scott Maclaren, Bo Galle, et al.
This paper describes the construction of a long-path fourier transform instrument based on a BOMEM MB100 spectrometer, as well as the initial application for VOC monitoring at an automobile painting facility. The instrument gave detection limits of about 100 ug/m3 for a number of aromatic hydrocarbons along a 350 m folded measurement path (single end retroreflector setup, 180 scans, 1 cm-1 resolution). The instrument also yielded a detection limit of about 10 ug/m3 for butyl acetate which promotes this compound to be used as a tracer for VOC emissions originating from the automobile industry. The paper also includes a description of the spectral analysis applied involving single component classical least square fit and correction for water vapor interference.
Fluorescent response of fuels in soils: insights into fuel-soil interactions
Sabine E. Apitz, Lisa M. Borbridge, Kim Bracchi, et al.
We have carried out experiments to examine calibration issues for a sensor system for real- time, remote, in situ monitoring of POL pollutants in soils, consisting of a pulsed UV laser/photodiode array fiber optic fluorescence system installed in a truck-mounted cone penetrometer. We have studied the fluorescent response of fuels as a function of soil type and conditions, and found that the fluorescent response of diesel fuel marine (DFM) varies by an order of magnitude or more as a function of soil type, exposure time, and moisture. The controlling variation for fuel fluorescent response is available surface area of the substrate, although exposure time, grain size, mineralogy, moisture and degree of soil aggregation cause secondary effects. Experiments to study the effects of long term exposure to sands and clays to DFM, with and without the addition of water, have provided insight into the interactions of fuel with the soil materials. Given time, DFM will soak into available pore spaces in a high surface area soil material, decreasing the bulk fluorescent signal over the first 10 - 12 days of exposure, and then stabilize. While the addition of water displaces some fuel from the soil surface and pores, this effect is limited in soils which are given adequate time to equilibrate. Such soil-fuel interactions may inhibit remediation efforts in clay-rich soils. Results from these experiments allow for more effective calibration of in situ fluorescent measurements in the field.
Methodological aspects and some results of urban pollution monitoring by remote and local sensing
Shepa D. Fridman, Leonid O. Volkov, Alexander I. Nakhutin, et al.
The necessity and efficiency of regulating local emissions cannot be assessed without taking account pollution connected with atmospheric transport. It is advisable to introduce the concept of ecological reserve of the local or urban atmosphere which is a difference between MPC and the background established by pollution transport. To estimate the background open- path measurement systems or local analyzers positioned above the rooftop level can be used. The ecological reserve for carbon monoxide was obtained for the northeast of Moscow by measurements at a height of 85 meters.
Biosensors for Environmental Monitoring
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Enzyme and microbial sensors for environmental monitoring
U. Wollenberger, B. Neumann, Frieder W. Scheller
Biosensors employing the biocatalyst on a different level of integration have been developed for monitoring environmental pollution. These probes range from laboratory specimen to commercial detectors applied to analyzers. This paper presents a selection of recent developments on amperometric enzyme and microbial biosensors. A monoenzymatic bulk type carbon electrode is described for biosensing organic hydroperoxides in aqueous solutions. Here, peroxidase is immobilized within the electrode body and the direct electron transfer between electrode and enzyme is measured. Both, reversible and irreversible inhibitors of acetylcholinesterase have been quantified by using a kinetically controlled acetylcholine enzyme sequence electrode. The inhibitory effect of pesticides such as butoxycarboxime, dimethoate, and trichlorfon could be quantified within 6 min in micrometers olar concentrations. Different multi-enzyme electrodes have been developed for the determination of inorganic phosphate. These sensors represent examples of sequentially acting enzymes in combination with enzymatic analyte recycling. Using this type of amplification nanomolar concentrations could be measured. A very fast responding microbial sensor for biological oxygen demand has been developed by immobilizing Trichosporon cutaneum onto an oxygen electrode. With this whole cell sensor waste water can be assayed with a sample frequency of 20 per hour and a working stability of more than 30 days.
Biosensor systems for pesticide determination in water
Ursula Bilitewski, Frank F. Bier, Baerbel Beyersdorf-Radeck, et al.
Different biosensor systems suitable for the determination of pesticides in water are described. They are based on immobilized biological components, which are sensitive to compounds commonly used as pesticides. The biological components in the work described here were microorganisms capable of degrading chlorinated aromatic compounds, cholinesterases which are inhibited by carbamates and organophosphates, and antibodies specific to triazines. They were immobilized on various carriers and were either integrated in automated flow-through systems or developed as disposable electrodes. In this contribution, characteristics features of the different formats are given, e.g., the dependence of the specificity and sensitivity of the system on the biological component.
Monitoring Environmental Biomarkers
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Use of biomarkers to assess environmental health
Lee R. Shugart, Richard S. Halbrook
Environmental pollution has received considerable coverage in the news media. This has stimulated public interest and generated pressure on private industries and governmental agencies to take corrective action. Because the environmental issues have at times been presented in a simplistic and sensational manner, the corrective response by regulatory agencies and industry is often cursory and narrow. An approach, using biomarkers (biological responses), for assessing the biological and ecological significance of contaminants present in the environment is described. Living organisms integrate exposure to contaminants in their environment and respond in some measurable and predictable way. Responses are observed at several levels of biological organization from the biomolecular level, where pollutants can cause damage to critical cellular macromolecules and elicit defensive strategies such as detoxication and repair mechanisms, to the organismal level, where severe disturbances are manifested as impairment in growth, reproduction, developmental abnormalities, or decreased survival. Biomarkers can provide, not only evidence of exposure to a broad spectrum of anthropogenic chemicals, but also a temporally-integrated measure of bioavailable contaminant levels. A suite of biomarkers are evaluated over time to determine the magnitude of the problem and possible consequences. Pragmatically, the biomarker approach will help to assess the health of the environment, and, in addition, will enable scientists to defend the advice they provide concerning environmental issues.
Heavy metals biomonitoring in the Mexico City metropolitan area
M. Carmen Gonzalez, M. Antonio Tenorio
Foliose lichens genera Parmotrema sp. and Parmelia sp. were used to monitor airborne heavy metal pollution in the Mexico City Metropolitan Area (MCMA). The samples were taken every three months in four selected places surrounding the urban areas (N, S, W, E). Also, another place far from the influence of the city was chosen as a reference site, and, lichens dwelling in Juniperus sp. twigs were transplanted from this site to our facilities in Mexico City and placed hanging from tree branches in order to measure the metal accumulation values in known time periods. Eight metals were measured (Pb, Cr, Cu, Fe, Zn, Cd, K, and Ca) due to their importance in the automobile and industrial pollution sector. The results show that lichens growing in near the MCMA get concentrations one order of magnitude over the lichens growing in the distant reference site. In particular Pb, Cu, and Zn present higher values south of the city which is in accordance with the dominant winds. Regarding the transplanted lichens, a significant increase in the concentration of Pb, Cu, and Zn was found after a nine month period.
Biomonitoring of carcinogenic substances: enzymatic digestion of globin for detecting alkylated amino acids
Michael Bader, Dankwart Rauscher, Kurt Geibel, et al.
We report the application of proteases for the total hydrolysis of globin with subsequent determination of amino acids. Optimization of the proteolysis was made with respect to enzyme concentration, time of incubation and type of protease. Ethylene oxide modified globin was used to compare the results of the analysis of the N-terminal amino acid valine after enzymatic cleavage to those obtained from the widely used modified Edman procedure. It is shown that the cleavage is of good reproducibility and yields more alkylated amino acid than the Edman procedure.
Monitoring benzo(a)pyrene exposure using laser-excited Shpol'skii spectroscopy of benzo(a)pyrene metabolites
Freek Ariese, S. J. Kok, M. Verkaik, et al.
Exposure to polycyclic aromatic hydrocarbons (PAHs) is considered a serious threat to the health of animals and humans and should be thoroughly monitored. Next to chemical analysis of PAHs in the various environmental compartments, PAH metabolites in body fluids (e.g., bile and urine) could be measured to determine the actual uptake. Although pyrene is not considered particularly toxic, its metabolite 1-hydroxy pyrene is often used as a biomarker because it is usually found at considerable concentrations and the analysis is relatively simple. As the result of differences in volatility and/or solubility, the uptake of more relevant carcinogens like benzo(a)pyrene may be some orders of magnitude lower and is far more difficult to measure. Determination of benzo(a)pyrene metabolites requires a very selective and sensitive method, and so far these compounds could only be detected after exposure to heavy pollution. In this paper it will be shown how several hydroxy benzo(a)pyrene metabolites are selectively determined using Shpol'skii spectroscopy. With this method, highly resolved fluorescence spectra are obtained upon cooling the sample in a suitable solvent to cryogenic temperatures. When a tunable laser system is employed as an excitation source, sub- femtomole amounts can be detected. Applications of the technique to marine monitoring (benzo(a)pyrene metabolites in fish bile) and to occupational hygienics (benzo(a)pyrene metabolites in workers' urine) are discussed. The data will be compared with 1-hydroxy pyrene concentrations to evaluate the routine use of the latter compound as a biomarker.
Biomarkers and Molecular Epidemiology
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Immunologic methods for monitoring carcinogen exposure
Regina M. Santella, Frederica P. Perera, Yu Jing Zhang, et al.
Immunologic methods have been developed for monitoring human exposure to environmental and occupational carcinogens. These methods involve the development of monoclonal and polyclonal antisera which specifically recognize the carcinogens themselves or their DNA or protein adducts. Antisera recognizing the DNA adducts of several polycyclic aromatic hydrocarbon diol epoxides have been used in competitive enzyme-linked immunosorbent assays to monitor adducts in tissue or blood samples. Elevated levels of DNA adducts have been seen in mononuclear cells of smokers and in total white blood cells of foundry and coke oven workers. Environmental exposure to PAH has been measured in individuals living in a highly polluted region of Poland. Antisera recognizing PAH-DNA adducts have also been used in immunohistochemical studies to monitor adducts in specific cells of biopsy samples. The DNA adducts of aflatoxin B1 have been monitored in liver tissue of hepatocellular carcinoma patients in Taiwan. Detectable adducts were seen in 50 - 70% of the patients suggesting that dietary exposure to this carcinogen may be a risk factor for cancer induction. Thus, immunoassays for monitoring exposure to carcinogens are an important tool in epidemiologic studies.
Exposure to propylene- and diethylene glycol ethers: analytical methods and biological monitoring
Bernd Huebner, Karl Heinz Schaller, Juergen Angerer
Twenty-two people involved with manufacturing brakehoses and exposed to the glycol ether 1- methoxypropanol-2, were assessed according to the external and internal exposure to this solvent. The elimination kinetics of 1-methoxypropanol-2 in man were studied and mean excretion half lives of approximately 4.4 h were found. On the basis of our results, we made a rough calculation for a future biological tolerance value for 1-methoxypropanol-2. On that basis we would expect that concentrations from 38 to 109 mg per liter of blood and 10 to 31 mg per liter of urine would correspond to the German maximum concentration at the workplace for 1-methoxypropanol-2 of 375 mg/m3. In addition, the analytical method which has been used for this purpose and its reliability criteria are shown.
Evaluation of 1-hydroxypyrene as a biological marker of industrial exposure to polycyclic aromatic hydrocarbons
Francisco Mercado Calderon
One hundred twenty-two workers (sixteen from a coke production plant and 106 from a graphite electrode manufacturing plant) agreed to participate in this study evaluating the relationship between exposure to polycyclic aromatic hydrocarbons (PAHs) and urinary excretion of 1-hydroxypyrene (1-HOP), the main metabolite of pyrene. The results show that the concentration of pyrene in air is highly correlated with total PAHs (r equals 0.83, P < 0.0001). The correlation coefficient between pyrene in air and 1-HOP is (r equals 0.69, P < 0.0001) and between 1-HOP and total PAHs is (r equals 0.77, P < 0.0001). The biological half life of the 1-HOP was determined (18 hrs) and the noninterference of smoking habits in relation to 1-HOP urinary excretion was established, concluding that 1-HOP is a suitable bioindicator of the occupational exposure to PAHs.
Intracellular Monitoring of Chemical Xenobiotics
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Microspectrofluorometric analysis of drug phototoxicity in single living cells
Patrice Morliere, Rene C. Santus, J. C. Maziere, et al.
The study of primary photobiological processes on the basis of structure-activity relationship is important for a better understanding of drug phototoxicity. An ideal approach for the understanding of the phototoxic response is provided by the study of drugs purposely used in photochemotherapeuties for which the determination of primary photochemical targets is a prerequisite for the investigation of the phototherapeutic action. For instance, in the so-called 'photodynamic therapy' of cancers, the photodynamic properties of porphyrins more or less specifically localized in tumors are responsible for their photocytotoxicity. Microfluorometry and particularly microspectrofluorometry are powerful non invasive techniques for carrying out quantitative photobiological investigations in real time in single living cells. This approach allows one to monitor the drug localization, to follow the drug fate, and to study photosensitized events in living cells. We illustrate some aspects of such investigations with photofrin II, a mixture of porphyrins currently used in phase III clinical trials, and other porphyrins including protoporphyrin which is encountered in genetic and drug-induced cutaneous porphyrias. To demonstrate the usefulness of microspectrofluorometry in such studies, we present data on the photosensitizer localization, on the photosensitizer photobleaching, and on structural or functional photosensitized damage to organelles.
Chemical Sensors I
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Perchloroethylene detection in air: a comparative study using polymer sensor elements and catalyst/sensor systems
Klaus-Dieter Schierbaum, S. Vaihinger, M. Haug, et al.
In a first approach, perchloroethylene (C2Cl4 or 'PER') was determined quantitatively in air by monitoring mass and temperature changes of polymer-coated quartz microbalance and calorimetric transducers. The different equilibrium and time-dependent sensor responses result from reversible interactions between perchloroethylene molecules from the gas phase and chemically sensitive polymers based upon modified siloxanes. In a second approach, we determined PER by applying pattern recognition methods to evaluate data from catalyst/electrochemical sensor-systems. Here, PER is decomposed at a heated catalytic filament. The molecular fragments are detected subsequently by an electrochemical or semiconductor gas sensor. The quantitative determination of perchloroethylene in air in the ppm-range is possible by applying mathematical procedures of pattern recognition. Finally, a comparative discussion of the different transducer and evaluation principles is given for specific applications.
Surface acoustic wave sensor array system for trace organic vapor detection using pattern recognition analysis
Susan L. Rose-Pehrsson, Jay W. Grate, Mark Klusty
A sensor system using surface acoustic wave (SAW) vapor sensors has been fabricated and tested against hazardous organic vapors, simulants of these vapors, and potential background vapors. The vapor tests included two- and three-component mixtures, and covered a wide relative humidity range. The sensor system was compared of four SAW devices coated with different sorbent materials with different vapor selectivities. Preconcentrators were included to improve sensitivity. The vapor experiments were organized into a large data set analyzed using pattern recognition techniques. Pattern recognition algorithms were developed to identify two different classes of hazards. The algorithms were verified against a second data set not included in the training. Excellent sensitivity was achieved by the sensor coatings, and the pattern recognition analysis, and was also examined by the preconcentrators. The system can detect hazardous vapors of interest in the ppb range even in varying relative humidity and in the presence of background vapors. The system does not false alarm to a variety of other vapors including gasoline, jet fuel, diesel fuel and cigarette smoke.
Chemical Sensors II
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Chemical resonant sensors
Peter R. Hauptmann
Resonant sensors designed to have a mechanical resonance frequency are a subject of special practical interest. They are sensors with outputs based on a quasi-digital frequency signal which is a great advantage over conventional analog sensors. Micromachined mechanical resonant sensors can be used to replace conventional piezoresistors in precision sensor applications such as pressure sensors and accelerometers. For the detecting of chemical species, only a part of known resonant sensor principles can be used for practical aims. Ultrasonic sensors can be classified in this category. They include BAW-, SAW-, APM-, and FPW-sensors. The theoretical concepts for their behavior and the advantages and disadvantages in comparison with other chemical sensors are discussed. Experimental results with BAW-sensors for gas and under-liquid sensing are given. Finally, the actual situation in research and industrial application of this sensor class is reviewed.
Chemical sensors in water protection control
Karl Cammann, Uwe Karst, J. Sander, et al.
The application of several selective chemical sensors and biosensors for monitoring water quality and thus facilitating water pollution control is described. Any regulation in the field of pollution control and environmental chemistry has to be accompanied by an analysis of the toxic substances. Many hazardous substances require continuous surveillance to determine the current toxicological status and the necessary remedial actions. Chemical sensors designed to detect threshold levels of chemical compounds can perform this function. The sensors require a built-in calibration to produce results which are not biased by interfering compounds. Production of these reliable sensors in great quantities will lower unit costs and make their use more cost-effective.
Design of a sulfur dioxide-selective optode membrane based on the fluorescence quenching of anthracene
Kemin Wang, Huihui Zeng, Zhen Qin, et al.
A new reversible optical sensing device is described for the determination of sulfur dioxide based on the fluorescence quenching of anthracene, which is immobilized in plasticized PVC membrane. With the optode membrane described, sulfur dioxide in sample solutions from 6.59 X 10-3 M to 5.23 X 10-1 M can be determined. The calibration curve for sulfur dioxide shows a good correlation with the mathematically-derived formalism and thus confirms the theoretically expected behavior. Besides a high reproducibility of the optical signals, the very short response times less than 30 sec. were realized. The optode membrane presented exhibits a good selectivity for sulfur dioxide.
Optodes for environmental chemical monitoring of lead
Markus Lerchi, Wilhelm Simon
Sensors with optical transduction (optodes) based on plasticized poly(vinyl chloride) (PVC) bulk membranes incorporating a metal ion-selective ionophore, a hydrogen ion-selective chromoionophore and lipophilic anionic sites for the measurement of lead are presented. Different ionophores were used to design new optodes for environmental sensing properties. Since sufficient detection limits and excellent selectivities over alkali and alkaline earth metals are reached, these sensors can be used as monitoring devices for environmental relevant purposes. These reversibly working optodes show different dynamic ranges depending on the basicity of the involved chromoionophore and on the pH of the sample solution. Therefore, these sensors can be tailored to a specific application by varying these two parameters. Dynamic range, detection limit, response behavior, short-time repeatability, stability and selectivity of the optode systems are discussed.
Nitrogen dioxide thin film gas sensors for environmental control
Klaus-Dieter Schierbaum, H. D. Wiemhoefer, Wolfgang Goepel
Thin-film structures of inorganic and organic electron-, defectelectron-, and ion-conducting materials were optimized to detect selectively NO2 in the gas phase for environmental control applications. We present results on electronic conductance sensors based upon SnO2 and PbPc, and on potentiometric sensors based upon the solid-state electrochemical cell Ag/AgI/PbPc/C.
Poster Session
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Chemical monitors based on surface-enhanced raman scattering
Tuan Vo-Dinh, Jean Pierre Alarie, W. S. Sutherland, et al.
This paper presents an overview of the development of chemical monitors using the surface- enhanced raman scattering (SERS) technique. The SERS effect is based on recent experimental observations, which have indicated enhancement of the Raman scattering efficiency by factors up to 108 when a compound is adsorbed on rough metallic surfaces having submicron protrusions. The focus of our research efforts is on the development of SERS-active sensors and instrumentation capable of field analysis and remote sensing.
Field Techniques
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Analytical chemistry: feeding the environmental revolution?
Jeannette G. Grasselli
There can be no question in anyone's mind that our ability to analyze the structure and composition of materials in all media has grown in amazingly exponential ways in the last several decades. Our detection limits have gone from micrograms to the subpicogram level. A millimeter-sized sample presented a challenge in 1950; but today we look at submicron units, in fact, at single atoms resolved in analytical electron microscopes in an almost routine manner. Analysis time has changed from hours or sometimes even days for a complete qualitative and quantitative analysis on a sample to modern capabilities which include real-time spectroscopy on in situ experiments which give us data on molecular dynamics in the femtosecond time regime. Trace analysis, the detection and determination of impossibly tiny quantities of elements and molecules in increasingly complex matrices, is readily accomplished today. These are exactly the types of samples usually involved in environmental analysis. Yet, there is a tendency among some groups to view analytical advances as a negative factor in environmental studies because the ability to measure extremely small quantities can focus regulators on placing restrictions on materials not previously detectable. If so, that is a rare instance where increased knowledge can be considered a setback.
Developing Raman spectroscopy for in-situ determinations
Thomas J. Vickers, Charles K. Mann
Raman spectroscopy produces highly characteristic responses from all molecular species. It uses ultraviolet, visible or near-infrared radiation and thus is well suited for use with relatively inexpensive low-loss fiber optics. Because it is a scattering measurement it is readily applied to samples in a variety of forms, including aqueous solutions, solids and slurries, and to samples in hostile environments. This report will discuss how concerns relating to sensitivity and reproducibility have been addressed by selection of appropriate instrumentation and data treatment strategies. Recent results with a fiber optic based system for a variety of samples with significant implications for in situ monitoring applications will be described. Problems relating to representative sampling of nonuniform materials have also been addressed, and results obtained with a novel Hadamard transform approach to obtain energy throughput and spatial averaging advantage will be described.
Subsurface screening of petroleum hydrocarbons in soils via laser-induced fluorometry over optical fibers with a cone penetrometer system
Stephen H. Lieberman, Sabine E. Apitz, Lisa M. Borbridge, et al.
A novel field screening method is described that couples a fiber optic based chemical sensor system to a truck mounted cone penetrometer. The system provides the capability for real- time, in situ measurement of petroleum hydrocarbon contamination and soil type to depths of 50 m. The technique uses a hydraulic ram in a truck with a 20 ton reaction mass to push an instrumented probe into the ground. Fluorescence is excited through a sapphire window in the probe by 337 nm light from a pulsed nitrogen laser. The excitation pulse is transmitted down the probe over a 100 m silica clad silica optical fiber. The resulting fluorescence from aromatic hydrocarbons in the soil is returned to the surface over a second fiber, dispersed with a spectrograph, and quantified with an intensified linear photodiode array. Field test data is presented that demonstrates how the system can be used for rapid three-dimensional delineation of a POL (Petroleum-Oil-Lubricant) contaminant plume at a hazardous waste site. Fluorescent fingerprints from 14 samples of 9 fuel types are used to show how spectral differences can be used for identifying contaminant sources. The effects of volatilization of different fuel types on the measured fluorescent signal are discussed.
Site and soil characterization of hazardous waste sites using an expert system guide
Roy E. Cameron
An expert system guide (knowledge book) has been devised to assist field personnel who must identify, describe, sample, and interpret size and soil characteristics of hazardous waste sites. The guide takes an approach that will be unfamiliar to most soil and environmental scientists and is directed to on-scene coordinators and project managers and others who may have little soil science training. It meets the need of the U.S. Environmental Protection Agency for standard procedures, guidelines, or protocols that address soil and site contamination, particularly heavy metals. The guide is organized to include: (1) general considerations and processes for collecting and using site and soils data, (2) detailed knowledge frames (descriptive profiles) of likely site and soil conditions, (3) a citation of references, (4) an appendix listing common sources of characterization data, and (5) a glossary of more than 900 general definitions.
Field Exposure Studies
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Waste incineration: estimation of the workers' internal exposure to PCB, PAH chlorophenols and other relevant agents
Juergen Angerer, B. Heinzow, D. O. Reimann, et al.
Fifty-four persons occupied in a municipal waste incinerator were examined with respect to their internal exposure to organic substances which are possibly produced during pyrolysis of organic matter. For this purpose the levels of benzene of blood, polychlorinated biphenyls (PCB) and hexachlorobenzene (HCB) in plasma as well as mono- (MCP), di- (DCP), tri- (TCP), tetra- (TECP) and pentachlorophenols (PCP) and hydroxypyrene in urine have been determined. Four hundred thirty-one men and women were examined for control purposes. Statistical significantly higher values for the workers were found for the excretion of hydroxypyrene 2,5/2,4-DCP, 2,4,5 TCP, and for the HCB level in plasma. For the concentrations of 4-MCP and 2,3,4,6-2,3,5,6-TECP the controls had significantly higher concentrations in urine than the workers in the incineration plant. No significant differences between workers and controls were detected with respect to benzene in blood, 2,4,6-TCP and PCP in urine, and to the levels of PCP congeners in plasma. The elevated levels of hydroxypyrene, 2,4-/2,5 DCP, 2,4,5-TCP, and HCB in biological material may be related to the incineration of the waste. These elevations, however, are very small and attract attention more from the environmental than from the occupational point of view.
Studies of the mutagenic effects of styrene to man: conclusions for the surveillance of styrene-exposed workers
Roland Rothe, P. Schmidt, T. Grummt, et al.
One hundred fifty-six styrene-exposed workers had a fourfold higher rate of chromosome aberrations in peripheral lymphocytes than the control persons. The parameters of clinical chemistry (liver, kidney, and blood) remained in the normal range. Further analyses of the data of this study revealed no connections of the degree of effects in clinical chemistry and the exposure level. But a connection exists to the duration of exposure (3 - 26 years): in the comparison of the mean values (all mean values within the normal range) significant differences were found between long-term exposed workers (more than ten years) and control persons. In the higher age groups (above 45 years) also the GAP-rate differences are more pronounced. Seventy percent of the TWA-values were found to be below 85 mg/m3; the arithmetic mean of the TWA-values 72,3 mg/m3. A health surveillance program to styrene-exposed workers is to be reviewed (clinical chemistry and genetic effects). Proposals concerning both problems are presented.
Use of BET for the estimation of the exposure of inhabitants of the North Moravian region to noxious chemical compounds
Jaroslav Volf, Jana Kubackova
In this article, a view is given of the activity of the Biological Exposure Tests Section at the Industrial Hygiene Laboratories and utilizing of exposure tests in industrial toxicology. The Exposure Tests Section analyzes more than 10,000 samples of biological material per year. In one sample, one or two injurants or metabolites are determined, mostly hippuric acid (toluene). The number of 'positive' findings of selected injurants is given. The question of biological monitoring organization is discussed. In the last ten years, physicians ensured the sampling of biological material. At present, this method limits the utilizing of results and their interpretation, and in this article a better method of biological monitoring organization is suggested, the biological material being sampled simultaneously with the air analysis on the working place. The possibility of using BET for categorization of workplace is illustrated.
Evaluation of possible health risk associated with occupational exposure to formaldehyde
Maria Vargova, Stanislav Janota, Jarmila Karelova, et al.
Widespread us of formaldehyde in a variety of applications is known to result in appreciable exposure of workers and large segments of the general population. Because of possible genotoxic and immunotoxic effects, we investigated the health condition of people occupationally exposed to formaldehyde in a plant in which woodsplinter materials are manufactured. The concentration of formaldehyde in the workplace was greater than the average and peak concentrations of formaldehyde in Czechoslovakia (0.5 mg/m3 and 1 mg/m3 respectively). Selected parameters of genotoxicity (cytogenetic analysis, nucleolus test) and immunotoxocity (serum immunoglobulin G, A, M; complement C3, C4; alpha-1-anti-trypsine, alpha-2 macroglobulin, ceruloplasmin, transferrin, prealbumin, orosomucoid levels) were determined. The results of the evaluation of mitotic indices and the blastogen transformation point to an effect of the exposure to formaldehyde on r-RNA synthesis inhibition and lymphocyte maturation decrease. The frequency of aberrant cells in the peripheral blood lymphocytes was increased in both, exposed and control group and was above 1.2 - 2% of aberrant cells observed in the normal population in Czechoslovakia. There was no significant differences in the values of natural immunity and specific humoral immunity. Significant differences were observed in the values of mitogen-induced proliferation of lymphocytes between the exposed and the matching and background control groups. These changes are considered to be sensitive indicators of the potential effects on the integrity of a more important immunologic function.
Poster Session
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Lung function, atopy, and chronic exposure to air pollution in schoolchildren living in two cities of different air quality
Eugen S. Gurzau M.D., Anca Gurzau, Marius Muresan, et al.
The question of a causative interrelation between air pollution and respiratory status has received considerable attention by the mass media in our country. Schoolchildren aged 7 to 11 living in two communities with different levels of air pollution were studied. The parents of these children filled out a health questionnaire. The prevalence of respiratory symptoms and pulmonary diseases was found to be significantly higher among children growing up in the polluted area (Tirnaveni) as compared with the low-pollution area (Dej). Lung function tests point out FEF25-75 disorders (and other lung disorders) at higher frequencies in schoolchildren living in the polluted area. Over 90% of schoolchildren living in the polluted area. Over 90% of schoolchildren with lung function disorders had a positive response to bronchodilatation. Of the schoolchildren with lung function disorders, 75.47% (p < 0,001) were atopic all of whom were sensitized to the down and house-dust.
Occupational glycol ether exposure: examinations to the evaluation of a limit value for biological monitoring of 2-ethoxyethanol and 2-ethoxyethyl acetate
Birgit Soehnlein, Karl Heinz Schaller, Juergen Angerer
Seventeen persons from a varnish production plant or the ceramic industry were examined for their excretion of 2-ethoxyacetic acid (EAA) in urine after occupational exposure to 2- ethoxyethanol (EE) or 2-ethoxyethyl acetate (EEAc). Sampling of urine was performed before and during an exposure-free weekend. On Friday post-shift a median value of 29,8 mg/l was determined for EAA in urine, on Monday morning of 10,7 mg/l. Based on the EAA elimination curves a medium half-life of 57,4 or 57,1 hours respectively was calculated. These values are considerably longer than values from literature (21 - 42 hours). As a consequence the German BAT value of 50 mg EAA per liter urine is only half as high as the currently discussed proposal for the American BEI value.
CO2 monitoring with solid state electrolyte devices based upon Na2CO3/BaCO3
H. D. Wiemhoefer, H. Keller, S. Brosda, et al.
Methods for continuous measurements of CO2 are of interest, e.g., in emission control, green house application, control of air quality in houses and automobiles. We give an overview on the status of techniques based upon the use of alkali carbonates for solid state electrochemical sensors, and we present new results which aim at estimating their performance and long-term stability in different environments. These results concern the sensitivity, the response times and their dependence on temperature and partial pressure of O2 and CO2, as well as the mechanism of gas interaction processes at the electrodes. A brief comparison is given of characteristic properties of these solid electrolyte sensors and of presently available other sensors operating with different transducer principles.
Rapid field-screening method for PCBs
Tuan Vo-Dinh, Wendi Watts, Gordon H. Miller, et al.
The analysis of polychlorinated biphenyls (PCBs) generally requires selectivity and sensitivity. Even after cleanup, PCBs are usually at ultratrace levels in field samples, mixed in with other halocarbons, hydrocarbons, lipids, etc. The levels of PCBs typically found in water, soil, tissue, food, biota, and other matrices of interest are in the parts per billion (ppb) range. Most current measurement techniques for PCBs require chromatographic separations and are not practical for routine analysis. There is a strong need to have rapid and simple techniques to screen for PCBs under field conditions. The use of field screening analysis allows rapid decisions in remedial actions and reduces the need for sample preparations and time- consuming laboratory analyses. Field screening techniques also reduce the cost of clean-up operations. This paper describes a simple screening technique based on room temperature phosphorescence (RTP) and provides an overview of both this analytical procedure to detect trace levels of PCBs in environmental samples.
Determination of platinum in blood and urine as a tool for the biological monitoring of internal exposure
Karl Heinz Schaller, Juergen Angerer, Friedrich Alt, et al.
The increased industrial use of platinum has led to a growing need for the determination of platinum levels in biological materials. Concern about the release of toxic material from catalytic converters in motor vehicles in the environment and about occupational platinum exposure of employees working in the assembly of motor vehicle catalyzers and recycling led us to establish background and internal exposure levels in human body fluids. The development of an analytical procedure, based on adsorptive voltammetry with an extremely high power of detection (2 pg Pt absolute) for the determination in body fluids made population studies reliable and practicable. The methods are described and the reliability criteria are presented. For 13 not occupationally exposed persons the platinum levels ranged in urine from <EQ 0,4 - 14,3 ng/l, in whole blood from <EQ 0,8 - 6,9 ng/l and in plasma from <EQ 0,8 - 6,9 ng/l. Employees (N equals 40) engaged in various workplaces with the manufacturing and recycling of platinum containing catalysts showed much higher platinum levels ranging from 10 - 2900 ng/l urine, 2 - 180 ng/l blood and 4 - 280 ng/l plasma. This was in agreement with the external exposure levels, which exceeded the German MAK value of 2 (mu) g/m3. Platinum concentrations in human biological materials seem to be suitable as internal exposure indicators.
Detection of PAH-aerosols by time-resolved fluorescence spectroscopy
Frank Lewitzka, Reinhard Niessner
An experimental technique for the detection of polycyclic aromatic hydrocarbons (PAHs) adsorbed on aerosols was developed. The principle of measurement is the time-resolved fluorescence spectroscopy. In our new set-up a nitrogen laser is employed for excitation of fluorescence. Results were compared with those of a former set-up in which a frequency- doubled dye-laser was used.
In-situ measurements on carbon aerosols with photoacoustic spectroscopy
Andreas Petzold, Reinhard Niessner
Up to now photoacoustic spectroscopy is the only available approach for an on-line and in-situ measurement of the absorption of radiation by airborne particles. The main disadvantage of the method is the need for a high-power laser in the visible or infrared spectral region with an optical output of 1 W or more as radiation source to achieve a detection limit for particulate carbon in the order of 1 (mu) g/m3. For the first time to our knowledge a laser diode was used to test the properties of this laser type as light source for photoacoustic spectroscopy of aerosols. The advantages of a laser diode compared with other high-power lasers in the visible are the emission wavelength of 800 nm, the small size of the laser, and the possibility of an electronic intensity modulation of the light instead of a modulation by a mechanical chopper, which results in a decreased background signal and an extended modulation frequency range.
Chemical Sensors II
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Photometric sensors based on sol-gel porous glass doped with organic reagents
Ovadia Lev, B. I. Kuyavskaya, Y. Sacharov, et al.
A new class of sensitive disposable sensors for determination of trace concentrations of water pollutants has been developed. It utilizes porous transparent silica glasses doped with organic photometric reagents. The silica sensors are produced at room temperature by the sol-gel procedure, i.e. by hydrolysis followed by polycondensation of tetraalkoxysilanes. Thus, we produced porous glasses doped with organic photometric reagents for the determination of typical cations, anions, pH, oxidation agents (e.g. disinfection agents) as well as typical air pollutants. A mathematical model for a flat plate monolithic iron sensor was developed and the predicted calibration curves were compared with the experimental response.
Field Exposure Studies
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Correlations between cadmium concentration in urine and exposure variables
Elmar Schwarz, Martina Chutsch, Christian M. Krause, et al.
As part of the study 'UMWELT und GESUNDHEIT 1985/86', a representative samples of the population of the Federal Republic of Germany was examined for urinary Cd. A log-linear prediction model based on 2109 cases led to an explained variance portion of R2 equals .32. Strong associations were revealed between urinary cadmium and the smoking history and age of the subjects. This is evidence of the function urinary cadmium has as an indicator of the Cd body burden. However, there are also clear connections with physiological parameters (urinary creatinine and serum urea), which are taken to be a modification of Cd excretion by renal function. The association between urinary Cd and serum urea can also be interpreted as a cadmium-induced renal dysfunction. Urinary Cd concentrations tend to be lower in regions with low industrial nitrogen oxide emissions and high economic dynamics, as well as in non- urban residential structures.
Poster Session
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New method for the determination of polycyclic aromatic hydrocarbons and halogenorganic compounds in air samples
W. Kleiboehmer, Norbert Huesers, Michael Arnold, et al.
This paper describes the very first results of the present authors' initial investigation into the use of supercritical fluid extraction of PAHs and PCBs from polyurethane foam sorbents. The presented results are the first steps towards the development of a novel analytical method for quasi continuous measurements of organic air pollutants.
Biomarkers and Molecular Epidemiology
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Development and application of human cell lines engineered to metabolically activate structurally diverse environmental mutagens
C. I. Crespi, Robert Langenbach, Frank J. Gonzalez, et al.
Cytochromes P450 are responsible for the mutagenic/carcinogenic activation of many environmental promutagens/procarcinogens. These enzymes are present at highest concentrations in liver in vivo but are markedly absent in tester organisms for most in vitro mutagenicity test systems. Two approaches have been used to supply needed metabolic activation, incorporation of an extracellular activating system, usually derived from a rodent liver and introduction of activating enzymes into the target cell. The latter approach appears to result in a more sensitive testing system because of the close proximity of the activating enzymes and the target DNA. Human cell lines have been developed which stably express human cytochromes P450 and other cDNAs which have been introduced individually or in combination. The resulting cell lines are exquisitely sensitive to exposure to promutagens and procarcinogens. Mutagenicity is measured at the hypoxanthine phosphoribosyl transferase (hprt) and thymidine kinase (tk) gene loci. The most versatile cell line, designated MCL-5, stably express five cDNAs encoding all of the human hepatic P450s known to be principally responsible for known human procarcinogen activation. The induction of mutation is observed in MCL-5 cells upon exposure to ng/ml levels of model compounds such as nitrosamines, aflatoxin B1 and benzo(a)pyrene. A lower volume mutagenicity assay has been developed for use with samples available in limited amounts. Human lymphoblast mutation assays have been used to screen for mutagenic activity sediment samples from a polluted watershed. Two sediment samples were found to have mutagenic activity to human lymphoblasts.
Analytical Techniques and Instrumentation
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Screening and characterization of pollution potential from solid industrial waste dumps
Irena Twardowska, Jadwiga Szczepanska
Solid industrial waste dumps, being an anthropogenic part of the vadose zone, are potential non-point sources of ground water contamination. The early warning provided from qualitative and quantitative information on contaminant migration within a dump is an essential element in monitoring and screening sites for hazardous waste deposition that prevents degradation of recoverable ground water resources and permits to avoid either false positive or false negative errors in evaluation and prediction of the extent of environmental hazard. Multilevel sampling of dump and vadose zone cross-sections in the defined points of known waste age and dump construction delivers direct information on vertical distribution of contaminants as a function of time, that is a resultant of a dump and vadose zone hydrogeology, as well as of the mechanism and dynamics of constituent release, interaction and biogeochemical transformation in pore solution. The current presentation describes a procedure for multilevel sampling, pore solution extraction and examination and provides data (vertical profiles of contaminants distribution from a selected landfill site) that exemplify necessity of dump/vadose zone multilevel sampling for correct assessment of contaminants migration rate, understanding processes and conditions affecting contaminant transport, and enhancement of remedial response measures.
Poster Session
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Influence of Cr(VI) on enzymatic activity of soil
Jerzy Pacha
The inhibitory effect of Cr(VI) on soil hydrolases activity during two different periods (one and six months) was investigated, in order to obtain information on the change in heavy metal toxicity with time. Considering toxicity as the ecological dose-50% (EcD50) toxicity tended to increase over six months for cellulase Cx, protease and acid phosphates and to decrease for amylase. The average EcD50 value varied between 4450 and 1210 ppm for cellulase Cx, 5000 and 2320 ppm for protease, 3830 and 3295 ppm for acid phosphatase, 4030 and over 5000 ppm for amylase.
Biomarkers and Molecular Epidemiology
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Cytochrome P450s and molecular epidemiology
Frank J. Gonzalez, Harry V. Gelboin
Cytochrome P450 (P450) represent a superfamily of heme-containing monooxygenases that are found throughout the animal and plant kingdoms and in many microorganisms. A number of these enzymes are involved in biosynthetic pathways of steroid synthesis but in mammals the vast majority of P450s function to metabolize foreign chemicals or xenobiotics. In the classical phase I reactions on the latter, a membrane-bound P450 will hydroxylate a compound, usually hydrophobic in nature, and the hydroxyl group will serve as a substrate for the various transferases or phase II enzymes that attach hydrophilic substituents such as glutathione, sulfate or glucuronic acid. Some chemicals, however, are metabolically-activated by P450s to electrophiles capable of reacting with cellular macromolecules. The cellular concentrations of the chemical and P450, reactivity of the active metabolite with nucleic acid and the repairability of the resultant adducts, in addition to the nature of the cell type, likely determines whether a chemical will be toxic and kill the cell or will transform the cell. Immunocorrelative and cDNA-directed expression have been used to define the substrate specificities of numerous human P450s. Levels of expression of different human P450 forms have been measured by both in vivo and in vitro methodologies leading to the realization that a large degree of interindividual differences occur in P450 expression. Reliable procedures for measuring P450 expression in healthy and diseased subjects will lead to prospective and case- cohort studies to determine whether interindividual differences in levels of P450 are associated with susceptibility or resistance to environmentally-based disease.
Air, Water, and Soil Monitoring
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In-situ measurements of volatile toxic organics in indoor air using long-path Fourier transform infrared spectroscopy
Martina Green, James N. Seiber, Heinz W. Biermann
A Fourier transform infrared (FTIR) spectrometer interfaced to a 2.5 m base path, open multi- pass cell was used to monitor indoor air in post-fumigation dwellings. The residual chemicals studied were the fumigant, methyl bromide and its odor additive, chloropicrin (Cl3CNO2). Indoor measurements with a time resolution of 15 minutes were performed for two houses of different age. Our results indicate that the newer dwelling, which contained insulation materials, appeared to retain substantial amounts of the fumigant. The highest concentration measured for methyl bromide was 24 ppm, close to five times the allowed TLV (Threshold Limit Value) of 5 ppm. For chloropicrin, we also observed a surprising level of close to 0.4 ppm, four times the TLV of 0.1 ppm. It was noted that the concentrations were very susceptible to any air movement such as that due to door opening. Analyses utilizing the conventional adsorption-desorption/GC technique were performed simultaneously by the Worker Health and Safety Branch of the California EPA. Although the vast difference in time resolution of the two methods precludes direct comparison of the data, averaging our measurements over the same integration time indicated that the FTIR methods gives significantly higher values than those obtained by the conventional method, especially when the pollutant concentrations are low.
Analytical Techniques and Instrumentation
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Measurement of traces of ammonia in flue gas with laser Stark spectrometry
Adriaan J. L. Verhage, Rudy A. Rooth, Leo W. Wouters
An infrared laser Stark spectrometer has been developed to measured NH3 concentrations in hot flue gas. The main application is the determination of ammonia slip after NOx- reduction with NH3 in power stations and chemical plants. Physical parameters that influence the results of measurements are tracked and their behavior is explained in terms of line shapes. A description of the instrument is given and results of NH3 measurements in flue gas are presented.