Algae grown under natural conditions in a pond are compared to cultivated algae (Microcystis). The initial phase of the induction kinetics until 50 ms can be described by two exponential functions with amplitudes F_a1 and F_a2 and time constants in the order to 1 ms and 10 ms. With the restriction of the observation time to 50 ms, the usual darkadaptation time can be considerably reduced. A variation of the power density I_a of the excitation light yields F_o (alpha) I_a 1.02, F_a1 (alpha) I_a 1.91, and F_a2 (alpha) I_a 1.57. The ratio F_a2/F_a1 scales the herbicide action and it can be related to a back reaction between PS-components.

The suitability of laser-induced fluorescence spectroscopy was evaluated as a method for the in-situ detection of water contaminants. For example, lead thallium, cerium, benzene, pyrene, toluene, xylene, naphtalene, and anthracene were investigated. The absorption-, fluorescence-, and excitation-spectra of each contaminant were measured in distilled water, artificial seawater and natural seawater as the examination of pollution spectra, that has been described in literature so far, does not characterize the contaminants dissolution in water. The chosen polycyclic aromatic hydrocarbons (PAHs) and heavy metals were excited by means of a frequency doubled dye laser, the latter being pumped by an excimer laser or by a frequency tripled Nd:YAG laser. The laser emitted radiation in the range from 220 nm to 400 nm. The fluorescence signal was recorded in the 230 nm to 600 nm range. The detection limits were in the ppb-range for the PAHs and in the ppm to ppb range for the heavy metals. Computer- simulations were applied to analyze the spectra of pollutant mixtures. They displayed a superimposition of the individual spectra. Discrete components of a mixture could be distinguished using this method. Finally, the influence of dissolved organic matter was investigated.

High resolution reflectance spectra, in the range from 400 to 850 nm, were acquired in Lake Kinneret during a period when dense populations of the dinoflagellate Peridinium gatunense dominated phytoplankton. Chlorophyll concentrations ranged from 5.1 to 185 mg.m^-3 and from 2.4 to 187 mg.m^-3 in the samples of two independent experiments. The most prominent features of the reflectance spectra were: 1) a wide minimum from 400 to 500 nm; 2) a maximum at 550-570 nm, which did not surpass 3% in samples with high chlorophyll concentration (> 20 mg.m^-3), indicating a strong absorption by pigments in the green range of the spectrum; 3) a minimum at 676 nm. It was approximately 1%, and was almost insensitive to variation in chlorophyll concentration > 10 mg.m^-3; and 4) a maximum reflectance showed near 700 nm. Its magnitude and position were highly dependent on chlorophyll concentration. High spectral resolution data were used as a guideline for the selection of the most suitable spectral bands for chlorophyll remote sensing. The ratio of the red reflectance maximum, near 700 nm, to the red minimum, near 670 nm, and also reflectance height above the baseline from 670 to 850 nm were used for construction of algorithms for chlorophyll determination. The best model, validated by independent data set, enabled estimation of chlorophyll concentration with an error of < 6.5 mg.m^-3. For the purpose of chlorophyll mapping in Lake Kinneret, the use of three relatively narrow spectral bands was sufficient. Therefore, a relatively simple sensor, with only few bands will be employed in future applications for chlorophyll monitoring in inland waters. Radiometric data were also used to simulate radiances in the channels of TM Landsat and to find the algorithm for chlorophyll assessment. The ratio of channel 4 to channel 3 was used and enable chlorophyll estimation with an error of < 15 mg.m^-3. This algorithm was used to map chlorophyll in the entire area of Lake Kinneret with 10 gradations.

The measurement of low concentrations of oil-in-water has been performed by fluoreometry but variations in the physical properties of different oils, in particular their dispersed particle sizes, significantly affect the degree of fluorescence and hence the accuracy of the measurement. Optical scattering can be used to investigate the physical state of oil-in-water suspensions, the strength and direction of the scattering being dependent on the physical and optical properties of the suspended particles. Optical scattering studies, in conjunction with neural network processors, have recently shown the capability to distinguish between oil suspensions over a range of concentrations. In this paper we extend the approach of combined nephelometry and neural networks and also investigate a technique for minimizing the complexity of design of the nephelometer. Whereas earlier work demonstrated the technique using dissimilar oil types in tap water, we here study the more practical and cogent example of similar oils (two crudes and an engine oil) in sea water.

Chlorophyll distribution in Haifa Bay was estimated in a period of very high chlorophyll concentrations (up to 70 mg/m³) using remotely sensed data. Radiometric measurements with spectral resolution of 2 nm in the range from 400 to 850 nm, were taken simultaneously with samples for chlorophyll concentration, turbidity and Secchi disk transparency. Prominent features of the reflectance spectra were a wide minimum from 420 to 500 nm, a maximum at 550-570 nm, a minimum at 676 nm and a maximum reflectance showed near 700 nm. High spectral resolution data were used for the selection of the most suitable spectral bands for remote estimating of chlorophyll concentration. The magnitude and position of the peak near 700 nm were highly correlated with chlorophyll concentration. The reflectance height at 690 nm above the baseline from 670 to 850 nm and area above the baseline were used as sensitive indicators of chlorophyll concentration. The best model enabled estimation of chlorophyll concentration with an error of less than 4.3 mg/m³. For the purpose of chlorophyll mapping in Haifa Bay, the use of three relatively narrow spectral bands was sufficient. Radiometric data were also used to simulate radiances in the channels of TM Landsat and to find the algorithm for chlorophyll assessment. The ratios TM3/TM1 and (TM2-TM3)/TM1 were used and enable chlorophyll estimation with an error of less than 8 mg/m³.

In this work, the method of the modulation intracavity laser spectroscopy is shown to be candidate for investigation and quantitative analysis of organic pollutions in water. The test specimen is placed into the cavity of the multimode dye laser. When the Raman scattering line coincides with amplification spectrum of the active medium of the multimode laser the additional gain appears at the Stokes frequency. One can experimentally determine this gain and then determine concentration of pollution. Spectral width of the Raman lines are small (approximately 3 cm^-1), therefore a number of organic pollutions may be observed simultaneously. We have investigated stimulated Raman scattering from molecules of peridin (C₅H₅N) in water. In our conditions concentration sensitivity was 7 IO^-4M/1.

Remote monitoring of toxic emissions is a major task in environmental and public safety control. Most applications in this field demand fast and robust sensors. We present a fiber- optical sensor system for the time resolved indirect monitoring of volatile organic compounds. The transducer is based on the interferometric measurement of the thickness of thin polymer films. When exposed to organic vapors, the polymer absorbs the components rapidly and reversibly. The corresponding volume change is detected with a resolution of 5 10^-6 r.u.. The limits of detection are within a few ppm for many hazardous compounds. The transducer is characterized with respect to stability of the sensitive coatings, sensitivity, and selectivity.

The 'on line' and 'in situ' detection of polycyclic aromatic hydrocarbons (PAHs) in exhaust aerosols of combustion processes is still one of the important tasks in analytical chemistry. Accordingly, within the framework of a scientific project with the financial support of the German Minister for Education, Science, Research and Technology, STN ATLAS Elecktonik GmbH, Bremen, is developing a fully automatic sensor system for the detection of PAHs absorbed on particles in exhaust aerosols. Time-resolved spectra of laser-induced fluorescence are measured. Two parameters, the decay time and the wavelength of the fluorescence are recorded and evaluated for the classification of different PAHs. In this paper the sensor system is described in detail and results of measurements in the exhaust gases of various industrial plants are shown.

Toxicity testing using fluorogenic compounds offers a number of advantages. These include a small sample volume, low cost, rapidity, and applicability to both a micro-organism monoculture and a biocenosis. The method relies on measuring the rate of enzymatic intracellular conversion of a fluorogenic substrate into a fluorochrome. We show how the rate of conversion depends on the substrate concentration, the biomass concentration and pH. We also show how the method can be used to measure the toxicities of several different toxicants, to study antagonistic and synergistic effects of different metal combinations and to study inhibition mechanisms. We then show that it is also possible to measure the cytoplasmic viscosity by exciting the fluorescein molecules in the cytoplasm with polarized light and measuring the polarization of the emitted fluorescence.

The effects of two air pollutant gases (SO₂ and O₃) on leaf photosynthesis (PS), leaf chlorophyll (Chl), chlorophyll fluorescence transients (CFTs), leaf reflectance (LR) and canopy reflectance (CR) in soybeans (Glycine max L. Merr.) were studied under both ambient- and elevated-atmospheric (CO₂) using open-top chambers. In the CO₂ vs. O₃ experiment, soybeans 'Clark' were exposed to charcoal filtered air (low-O₃) or ambient air + 40 nL L^-1(O₃) (high O₃) during 7 h day^-1, 5 days week^-1 having (CO₂) of 350 (mu) L L^-1 CO₂ (ambient-CO₂) or 500 (mu) L L^-1 (enriched-CO₂) for 12 h day^-1. In the CO₂ vs. SO₂ experiment, soybeans 'Essex' were exposed to charcoal filtered air (low-SO₂) or + 120 nL L^-1 SO₂ (high-SO₂) during 5 hr day^-1, 5 days week^-1 having the same (CO₂) as for the CO₂ vs. O₃ experiment. Plants were exposed to treatment gases from early growth until maturity. In the CO₂ vs. O₃ experiment, leaf PS, leaf Chl, and CR showed trends of reduced values under high-O₃, while LR was largely unchanged. Leaf PS and CR had increased values under enriched CO₂. Leaf Chl and LR were not affected by CO₂ enrichment. In the CO₂ vs. SO₂ experiment, CFTs values indicated that the gases has no impact on the light reactions of photosynthesis. Reduction in leaf PS, leaf Chl, and CR were observed under high-SO₂ while LR was unchanged. The enriched CO₂ environment increased leaf PS rates but had no effect on LR and leaf Chl.

Tunable diode laser spectroscopy (TDLS) is proposed for content measurements of trace gases like CO, CO₂, NH₃, CH₄, NO, NO₂ in human and animal's exhalation. High sensitivity and wide dynamic range of the method ensure fast detection of these gases at ppb level and within the accuracy better than 10%. One-expiration sample is enough to reach these parameters. There is no need for any preliminary preparation of tested samples. Some pairs of the gases, for instance, CO and CO₂, NH₃, and CO₂, and CO and N₂O, can be measured simultaneously by one laser providing complex studies. The high sensitive gas analysis could provide necessary background to the noninvasive diagnostics in a wide variety of medical problems. Perspectives of the TDLS methods in application to medicine diagnostics are demonstrated by the first results of exhalation tests.

The investigations of the asymmetrical Fraungofer type diffraction patterns allowed me to propose a method for testing a refractive index of the transparent objects. The two modifications for measuring a refractive index are presented. The first was based on effect from the longitudinal shift between two knives of the diffraction slit. The information about the exchange of refractive index we can obtain by analysis coordinates of the diffraction pattern extremes. The second was a modification of Young experiment. In this scheme the slits are separated in the direction of propagation of the incedent radiation. A deviation of etalon's and sample's indeci of refraction is determined by analysis of interference pattern in central diffraction maximum.

Hyperspectral monitoring is becoming an increasing method for satellite and airborne remote sensing. The rapidly developing optoelectronic technology of the last years has promoted this method. Regarding the characteristics of the VIS-spectrum, the most prominent features are located between 600 and 800 nm. High spectral resolution of 1 to 2 nm within this region shows various peaks which are correlated with organic compounds and micro-organisms. Since pollution is often represented by presence and growth of organic substances and micro- organisms, kind, extent, and distribution in water environments can be detected by hyperspectrometry. The hyperspectral method is still limited by its recording velocities, while applied on high ground speed flying aircrafts. This has impacts on the data gain, quality, and interpretation. Airborne hyperspectrometry was applied for pollution detection in water environments such as lakes, ponds, rivers, coastal and ocean regions, and wetlands. Results are shown and interpreted.

Conformational transformation of dissolved humic substances induced by acidic and basic additives in water has been investigated by automated subnanosecond laser spectrofluorimeter and fluorescent probe method. The equilibrium constants for binding of rhodamine 6G to dissolved humic substances in water have been determined by a fluorescence quenching method. It is shown that the conformational structure of humic compounds in water depends on the intra- and intermolecular interactions. Spectral and viscosimetrical data in pH region 1.5-12.0 are interpreted in terms of conformational transformation of dissolved humic substances from a rigid globule to a flexible chain.

Recent developments in atmospheric monitoring with a ground-based FTIR spectrometer are presented. Several aspects of the inversion method for the retrieval of temperature and humidity profiles from IR emission spectra are reported. The main objective of the study is the evaluation of the retrieval method as a support in pollution monitoring by FTIR emission spectroscopy. Through an analysis of recent experimental results the accuracy of predicting experimental signature of pollutants with retrieved profiles is established. The possibilities of the method are illustrated by the evaluation of CFC-11 and CFC-12 mixing ratios from a typical radiance measurement.

Rapid diagnosis of pollution is one of the key tasks in the field of ecological monitoring of natural and technogeneous environment. One of the promising methods of fluorescent diagnosis of organic pollution of water environment is the registration and analysis of 2D spectral fluorescent signatures (SFS). The neural networks-based system suggested in this paper is intended for solving the problem of detection, identification, and concentration measurement of water environmental pollution. The suggested system uses SFS as input pattern and allows one to build a rapid diagnosis system for ecological monitoring.

An approach of on-line fluorescent analysis of organic compounds in a water is described based on multiwavelength sensing of water environment. Developed techniques are realized in remote mode to inspect large water surfaces as well as in flow-trough mode to diagnose the water quality in the pipes and open streams. The tuneable fluorescent lidars FLS-S and FLS-A for shipboard and airborne applications and compact flow-through spectrofluorimeter FLUO- IMAGER are described.

At present a number of ozone analyzer types with their own advantages and disadvantages are produced in Russia. Being wide in use the chemiluminescent ozone analyzers need a calibrator (ozone generator) with specified ozone concentration to compare with ozone concentration measured in the atmosphere. The authors describe a 2-beams UV photometer to graduate ozone generators. The instrument allows to measure background ozone concentrations in the ground layer of atmosphere. It has two equal absorption chambers (cells) switched alternately by two gas solenoid valves from the reference to measurement modes. The concentration value is determined by discrepancy.

An advanced type of ozone analyzer for measurement of ozone solved in water and aqueous solutions with different mud content levels has been developed. The operating principle of analyzer is based on the relationship between the balanced ozone concentration in a gas phase under solution and the gas concentration in the aqueous solution. Under solution and the gas concentration in the aqueous solution. Under isothermal condition this dependence can be described by the Henry equation. The ozone concentration in the gas phase is determined by a chemiluminescent method. The solid-state chemiluminescent sensor is operable under humidity of 100%. The range of measured concentrations is 25-25 000 ppm (0.05-5.00 mg/L).

The atmospheric pollution concentration is usually determinated by the differential absorption (DA) method using spectral absorption lines of pollution. It is known the relationship between absorption and the phase refractive index (PRI) of medium is given by the Kramers-Kronig ratio. The maximal difference of PRI near spectral line will be more than DA sensitivity. Using the Raleigh's relation the group refraction index (GRI) may be obtained too. Investigations show that the GRI has a considerably much deviation (about million times) near absorption line then the PRI. It is proposed to use above deviation for atmospheric pollution determination by measuring propogating signals differential group delay (DGD) between extremal deviation points. It is shown that the new method sensitivity is 10-20 and more times higher than with DA method.