Organic Micropollutants in the Aquatic Environment

Mass Spectrometry in combination with gas chromatography (GC-MS) has been applied to the analysis of organic compounds in water for over a decade. Initially, because of the high costs involved, only a few central research laboratories possessed such equipment. However, in the last few years, mass spectrometer manufacturers have produced smaller bench-top mass spectrometers at lower prices so that GC-MS facilities have become more widely available. The UK water undertakings have, collectively, considerable experience of the two most commonly available bench-top GC-MS systems — the Finnigan Ion Trap Detector (ITD) and the Hewlett-Packard Mass Selective Detector (MSD). Typical applications of these two systems to the analysis and monitoring of various organics in water will be described, and factors such as ease of use, reliability and the quality of the data produced by the ITD and MSD will be discussed.

A multidimensional chromatography system with a packed fused silica Micro-LC column connected on-line with a capillary GC column is described.The Micro-LC column can act as a sample clean-up or/and a chemical class separation column prior to introduction of the sample into the capillary GC column. This technique was used for analyzing complex mixtures and/or trace compounds in complex matrixes.

Some examples are given for the progress being made in the analysis of the 129 EC priority pollutants (Easily volatile halogenated hydrocarbons, benzene and derivatives, chloroethene, phenolic compounds, polycyclic aromatic hydrocarbons). The results of interlaboratory trials, as far as available, are stated and interpreted. Preliminary results on test methods are offered. Some reasons for the slow progress is given.

For many applications involving the extraction, concentration and purification of organic micropollutants from water samples, the use of bonded silica extraction columns can be a valuable alternative to traditional sample preparation techniques such as liquid-liquid extraction. The commercial availability of a wide range of bonded silica sorbents means that extraction and clean-up procedures can now be developed utilizing non-polar, polar and ion exchange mechanisms.

The quantitative performance of steam distillation extraction for the isolation of nine priority pollutant phenols from water was studied, and the recoveries compared with those of the direct extraction with dichloromethane and the two step extraction using tetrabutylamonium as ion-pair reagent. For a concentration of 1 mg 1=1 using acidification, strong salting of the water sample and a distillation time of 1.5 h. the recoveries are similar to those obtained with extraction in acidic medium with dichloromethane.Compounds of high polarity with strong interactions with water by hydrogen bonds, as p-nitrophenol, are not extracted by stream distillatio-extraction method.

A clean-up procedure for the isomer-specific analysis of polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs) in oil extracts from water leachate of a hazardous waste landfill is described. The samples were chromatographed on Alumina B-Super I, silica gel combined with silica gel/44% conc. H₂SO₄, and on Bio- Beads S-X3. Separation of 2,3,7,8-tetra-CDD and final sample purification were performed on Alumina B-Super I (micro column). Among the 2,3,7,8-tetra- to hexa-CDDs/CDFs, 2,3,7,8-TCDD was by far the most abundant isomer, determined at a mean concentration of 70,5 ppb. Industrial wastes from 2,4,5-trichlorophenol production are assumed to be the main source for this high concentration. From the isomer distribution pattern of the hepta-CDFs, pentachlorophenol can be considered as source of the higher chlorinated PCDDs/PCDFs.

The pollution by pesticides is studied in lake Albufera of Valencia (Spain) to determine the hazards involved in the pesticide treatment of nearly rice field and forest and in urban and industrial contamination.At present Molinate, Benthiocarb and Fenitrothion are the pesticide which have been found to reach the highest concentration in waters from the lake.DDT and BHC were the most frequently detected organochlorinated pesticides in this ecosystem.

For the automated analysis of gasoline components in water samples a gas Chromatograph equipped with a multifunction controller, an on-column autosampler and a data acquisition system was used. Use of retention indices improves the reliability of the identification. However, components which differ less than 0.7 index units could not be discriminated by the available acquisition software. Further improvements of retention indices with the described equipment are not possible. Improvement of the GC-equipment is less important. A more accurate retention time registration is necessary. Control runs with GCMS are recommended. Pattern recognition techniques could be helpful to avoid serious mistakes in identification and quantitation.

A new method for the enrichment of pesticide residues in water by liquid/liquid extraction with n-pentane in a light phase rotation perforator according to Ludwig is described. Altogether 44 compounds (chloropesticides, urones, triazines, phosphoric acid esters and others) were analyzed at given concentrations by gas chromatography. Four phosphoric acid esters and two other compounds showed insufficient recovery rates between 50% and less than 10% due to their decomposibility in aqueous solutions. All other analyzed substances showed very good average recoveries of 80% to 115%. Detection limits ranged from 10 to 100 ng/1, dependent on the detectors (ECD. PND) and enrichment factor (1000 and 2000, respectively). The applicability of this enrichment method to residue analysis of pesticides in surface water and groundwater is demonstrated and its practicability is discussed.

The coupling of several analytical techniques Yia appropriate interfaces for monitoring selected organophosphorus pesticides (OPs) included in the EEC list of priority pollutants is illustrated. By utilizing positive and negative ion (PI and Nl, respectively) “filament on” tnermospray liquid chromatography-mass spectrometry (TSP LC-MS) and positive and negative chemical ionization (PCI and NCI, respectively) in direct liquid introduction (DLI) narrow-bore LC-MS, with acetonitrile-water mixtures, the characterization of several OPs is achieved. The use of 1% chloroacetonitrile in the LC mobile phase in DLI LC-MS is also discussed. Finally, reyersed-phase narrow-bore LC coupled to a thermionic detector (LC-TID) is carried out with methanol-water mixtures as eluent. Applications are reported for the determination of OPs in aquatic environments.

Within the Tagus estuary, in the vicinity of an industrial zone (chloroalkaly, pesticides, fertilizers and steelworks plants) a monitoring programme on Organochlorine Pesticides and Polychlorinated Biphenyls has been carried out since 1983.This zone is influenced by agriculture activities as well. Flounder (Platichthys flesus) and eel (Anguilla anguilla) have been sampled twice a year. Analysis have been carried out both on liver and fillet. Low concentrations were observed which present neither risk for survival and normal development of living species nor to public health.

This is a method for determination of lignin and humic substances in waters by HPLC with fluorimetric detection. Water samples are extracted with ethyl acetate and the carboxylic acids in these extracts are labeled with 4-Br-MMC. Results indicate that this method might be applicable to characterzation of humic waters and differentiation of humic and lignin compounds in recipient waters of pulp mills. Further experiments are needed.

Polychlorinated phenols, guaiacols and catechols have been studied in snow from North Pole, North, Central and South Finland. Only Central and South Finland samples contained known compounds above limit of determination 0.5 ng/1. Airborne chlorophenol pollution appeared to be very much higher in South than in Central Finland.

An evaluation of an analytical method for volatile sulphur compounds arose from the need to monitor compounds known to cause nuisance odours in atmospheres near sewage treatment works. A technique using thermal desorption from Tenax adsorbent, cold trapping and transfer on to a capillary GC column before chromatography which has been applied to qualitative analysis of a broad range of organic compounds by gas ciiraoratography-mass spectrometry was evaluated and subsequently modified to meet the demands of the analysis of a range of reactive volatile sulphur compounds by gas chromatography using a sulphur-selective flame photometric detector. Factors affecting recoveries from the adsorbent were identified and efficiency of transfer significantly improved.

Sediment samples from three relatively unpolluted estuaries in south west England have been examined. All three estuaries (viz those of the rivers Dart, Exe and Teign) drain predominantly agricultural land and receive only low volumes of primarly domestic effluents. The results of this investigation have shown that the major components in the samples are of biogenic origin. They include components of the leaf waxes of higher plants (nC₂₇, nC₂₉ and nC₃₁ alkanes), a long chain (C₂₆) alcohol and sterols. Two of the latter, coprostanol and cholesterol, probably originate from sewage or animal waste discharges to the estuaries.

During a survey undertaken in 1986 for triazine herbicide determination in surface and drinking water in Northern Italy,phosphate esters were found as ubiquitous interfering compounds,using the GLC technique with a nitrogen/phosphorus specific detector.As these compounds occurred very frequently at levels higher than herbicides,they were identified and quantitatively determined. TBP(tri-n-butylphosphate),TIBP (tri-iso-butylphosphate) and TCEP(tris-2chloroethylphosphate) were very frequent in river Po, river Adige and Como lake waters as well as in drinking waters derived from these surface supplies.Groundwater was much less polluted.Treatment processes could reduce this contamination: filtration on activated carbon was a veryefficient system.However,reduction of this pollution at the source,at least for the most dangerous compounds,should be the most convenient policy.

The degree of pollution by nitrilotriacetic acid (NTA) of Tiber and Aniene rivers has been evaluated employing a methodology developed in a previous work (1). The analitycal procedure involves extraction from water sample, conversion to trimethylester and analysis by capillary gas chromatography.The NTA concentration increase in both rivers when these pass through the city of Rome.

Sediments collected from Iraklion gulf and Chania gulf (North Crete) were analyzed to assess the status of anthropogenic hydrocarbons input. Aliphatic, aromatic hydrocarbons and molecular markers such as sterane and hopane-type compounds were determined, by GC and GC/MS, for source identification.

The cause, course of events, and consequences of the Sandoz warehouse fire, Schweizerhalle, Switzerland, on 1st November 1986, are presented. The flux of matter to the atmosphere, to the soil, to the groundwater and to the Rhine River is discussed, and the chemicals released to the environment are characterized. Some aspects of the clean up operations and their success are also described.

Water quality of the river Rhein has been gradually improved in comparison to the situation in the 7oies. Thus more sensitive aquatic organisms are now settled in the water body and the banks of Rhein river. Therefore accidental events are now more important for the river possibly deteriorating the water quality. Even more important, drinking water supply may be endangered especially by those substances which are not eliminated in the purification process. In 1986, a number of contaminations of the Rhein water were reported, most of them caused by accidents in chemical production plants. The monitoring strategy for the Rhein in Nordrhein-Westfalen has proven to be succesful, the monitoring system should be enhanced.For rapid detection of contaminants in the river, monitoring activities include sensitive chemical screening methods as well as biological tests. In order to control waste water and cooling water discharge, automized analytical systems should be installed directly at the discharge points of a chemical production plant to detect irregularities as fast as possible. Moreover chemical companies should be enforced to install samplers working automatically. As decisions have to be taken very quickly, valid data on the behaviour of all possible and relevant contaminants with respect to raw water purification should be available on-line.

Two simple models are presented for predicting transport behaviour of pollutants, in case of accidents in a river. The first model is especially suitable for predicting transport in the neigbourhood of the accident, while the second model can be used for longer distancies, including inflcw, outflow and velocity variations. Relevant model parameters are discussed and attention is payed to the description of elimination processes. Furthermore the effects are discussed of exchange processes, not accounted for by the models.

A study of the transport and fate of organic pollutants in rivers has been initiated by the selection of a site for study from among seven candidates. Analysis was carried out on the water, suspended particulates and sediments at the selected site to assess the representativeness of the sampling procedures and determine a range of compounds suitable for the detailed transport and fate study. The selected compounds were mostly anthropogenic in origin and included several potential EC list 1 and related chemicals. Calculations were carried out to determine the analytical requirements for the detailed study and the proposed research programme is outlined.

Aqueous solubilities of three chlorobenzenes in sediment-water systems are significantly enhanced by the presence of third phase material originating from the sediment. Because the aqueous concentrations of the chlorobenzenes are influenced by this third phase material, their sorption coefficients will also be influenced. Besides the experimental conditions, the characteristics of the sediment determine the third phase concentration. Pretreatment of the sediment, such as drying in an oven can change these characteristics significantly.

In a-biotic samples obtained from the natural aquatic environment evidence has been reported for the presence of silicones from antropogenic sources. It has also been reported however that a-biotic transformation may play an important role in the environmental fate of these chemicals. In particular clay catalyzed hydrolysis may be important. Hitherto little is known about the ability of (micro)organisms to transform silicon compounds. Since most organosilicon compounds are che micals with very low aqueous solubilities and high solubilities in organic solvents it was expected that these chemicals would accumultae to high concentrations in organisms. This however, is not what has been found in laboratory tests with fish or mammals, or in biota sampled in the natural environment. The low bioaccumulation factors may be explained by high rates of elimination of the short chain silicones and by a lack of uptake for the long chain chemicals.

Sediments sampled within Saronicos gulf (Greece) were used as geoaccumulators for the assesment of the status of petroleum pollution in this area. Molecular markers, namely were studied to identify the source of this pollution. The results were compared with those obtained from a spectrofluorometric analysis.

On 1 November 1986 a fire at a Sandoz warehouse resulted in a massive input of chemicals to the atmosphere, Rhine River and surrounding soils. The wave of chemicals in the river, predominately Disulfoton and Thiometon, was monitored as it traveled to the North Sea. This chemical wave resulted in the death of benthic organisms and fish, especially eels. From the measured and estimated concentrations, Etrimfos, Endosulfan and Formothion were probably the lethal chemicals. The measured water concentrations from the period directly following the accident suggest that some of the chemicals were lost from the main wave before it reached the North Sea. Based on the physical, chemical and biological properties of the pesticides and the hydraulic characteristics of the Rhine, the fate and transport of the chemicals have been modeled. It is predicted that most were quickly flushed from the river. The exceptions are the mercury compounds and possibly Endosulfan. Other than these there should be no residual of the chemicals in the water, sediment or biota.

The occurrence and leaching of some widely used pesticides were studied in 1985–1987 in an experiitiental field, in a small agricultural drainage basin and in a river highly loaded by agriculture. Phenoxy herbicides were found in most of the samples and the highest concentrations were measured in πddsummer, soon after the application. High concentrations were usually associated with heavy rainfall events. Trace amounts of some highly toxic insecticides could also be detected in the same samples.

The presence of polychlorinated biphenyls (PCBs) was investigated in samples of water, suspended particles, sediments and fish from the Kupa river, Croatia, Yugoslavia, along a river stretch extending up to 10 km upstream and 200 km downstream of the primary contaminated karst region. The PCB levels detected in the samples collected downstream ranged from 1 to 52 ng dm−3 for water, from 50 to 190 μg kg−1 for suspended particles and from 8 to 39 μg kg−1 for the sediment. A wide range of PCB concentrations, from 0.1 to 42.3 μg g−1, which were measured in edible portions of different fish confirmed a long-term contamination of the river with PCBs. As the Kupa river may be classified among low to moderately contaminated waters, it is essential that the investigations of the presence and behaviour of PCBs in the river and its environment be continued.

Chemostat (continuous) cultures of microorganisms offer a number of advantages for the study of the biodegradation of xenobiotic chemicals compared to the more commonly used batch systems. Chemostat cultures enable the influence of environmental conditions and adaptation on biodegradation to be studied, as well as simplifying kinetic studies.The cometabolic degradation of chlorobiphenyls by a Pseudomonas strain in batch and chemostat cultures was compared. In batch cultures there was ready degradation of mono- and dichlorobiphenyls, but not of tetrachlorobiphenyls, In contrast, tetrachlorobiphenyls were degraded in chemostat cultures exposed continuously to the compounds by means of a generator column. Degradation was apparently enhanced by the more favourable conditions in chemostat cultures, and not by adaptation of the bacteria.First order biodegradation rate constants for the tetrachlorobiphenyls were calculated from the steady state concentrations in the cultures and the exposure concentrations. The rate constant for 2,2′,3,3′-tetrachlorobiphenyl was much higher than those for the 2,2′,5,5′- and 2,2′,6,6′- isomers, suggesting that steric hindrance of 2,3-dioxygenation controls their degradation rates.

Several aspects of the anaerobic biodegradation of organic compounds are presented in this paper. The role of molecular oxygen in the metabolism of organic carbon compounds is summarized, followed by a discussion of some of the pathways and the electron acceptors involved in the degradation under anaerobic conditions. Several degradation mechanisms are demonstrated for selected aliphatic and aromatic xenobiotic compounds. Examples are given of factors which will strongly influence a degradation of anthropogenic substances. Finally, existing methods for biodegradability testing, their limitations, and some suggestions for improvements are described.

An account is given of microbiological procedures for investigating the fate of xenobiotics discharged into the aguatic environment. A brief account is given of the experimental procedures which have been developed, and their application is exemplified from the results of experiments with chloroguaiacols and related compounds. Experiments encompass both aerobic and anaerobic transformations, and emphasis is placed on environmental factors of cardinal significance in determining the outcome of laboratory experiments. An attempt is made to assess the environmental relevance of the data acguired by carrying out experiments in which natural sediment samples were spiked with the xenobiotics. Attention is directed to the significant role of binding to sediments.

The presence of 4-chloro-, 2,4-dichloro-, 2,4,5- and 2,4,6-trichloro-, 2,3,4,6-tetrachloro- and pentachlorophenol was investigated in sample of the Sava river water and of ground and drinking water collected in the Zagreb area. In almost all of the 25 river water samples higher chlorophenols were detected, with pentachlorophenol present in highest concentrations, but not exceeding 160 ng dm-3. The levels of chlorophenols in ground water samples collected in 18 wells depended on the location and distance of the well from the Sava river bed. Their presence in the river water did not appear to have an effect on the purity of ground water sampled from wells about 2 km away from the river, among which ten supplying water to the Zagreb waterworks. However, single chlorophenols were detected in samples of both chlorinated municipal drinking water and non-chlorinated drinking water from privately owned wells. The occurrence of chlorophenols in drinking water samples seemed to be mainly a consequence of occasional contamination of ground waters network in the city of Zagreb, where waterworks pumpstations and private wells are located in certain city areas often near industrial plants.

The approach of using integrated programs of biological and chemical tests for characterization of industrial effluents has been applied for hazard assessment by the regulatory agences in Sweden for some years now. Most cases are connected to the claim on municipal and industrial facilities to obtain discharge permits. In other cases testing programs have been used for directing process modifications or external treatment techniques towards a minimization of the environmental effects from the discharge.The biological testing has found the widest and most efficient application for industrial plants with processes emitting complex effluents with largely unknown chemical composition and environmental impact.The test programs are applied in a flexible manner depending on the type of industry with its process modifications, raw materials and chemicals added. The character of the receiving water body is taken into consideration when choosing the test organisms.

A survey is presented of practical management oriented methods and strategies for environment fate testing of chemicals and effluents with main emphasis on biodegradability. The major framework of the paper is the EEC legislative tests and current international cooperative work on test development and test harmonization. It is pointed out that test methods and strategies developed for use in connection with notification and general regulation of chemicals can be used in modified form for testing of specific effluents.

Dissolved and particulate LAS, NP, N1PEO and NP2EO were determined in raw sewage, primary effluent, secondary effluent, primary and secondary sludge of the sewage treatment plant Zürich-Glatt on two consecutive sampling days. The results were combined with sewage flow rate and dry matter load measurements in order to obtain the respective mass fluxes. The latter provided information on the major removal processes affecting these detergent derived chemicals, i. e. biodegradation during the activated sludge treatment and incorporation into sludge. The overall removals of LAS over the two sampling days were 99.3% and 98.7% (w/w), of which 13% and 16%, respectively, were found in raw sludge and 9% and 13%, respectively, in anaerobically digested sludge. Both NP1EO and NP2EO were poorly removed in the secondary effluent and were educts for NP in sludge. Nonylphenol loads in the anaerobically digested sludge were 4.7 and 6.4 times larger than in the raw sewage.

Chlorination of lignin and humic material in water produces the strong bacterical mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-fura-none or its acyclic form Z-2-chloro-3-(dichloromethyl)-4-oxo-butenoic acid (“MX”), and its geometric E-isomer (“E-MX”). Although MX is a trace component in the mixture of chlorination products, it is the main single contributor to the Ames mutagenicity in wood pulp chlorination liquors as well as in chlorinated drinking waters. Higher mutagenicity and higher amounts of MX and E-MX are produced during chlorination under acidic conditions than under neutral conditions. Substitution of chlorine by chlorine dioxide decreases the formation of mutagens. Although E-MX has a much lower mutagenicity than MX the compound is of concern since it can be isomerised to MX. This conversion occurs particularly under acidic conditions. MX reacts with sulfite and sulfide. Sulfite treatment may be a feasible process to remove chlorinated mutagens from both bleaching waters and drinking waters.

The application of bacterial mutagenicity tests to drinking water has shown the presence of mutagens. Invariably, mutagens generated during water treatment chlorination account for much of the mutagenicity detected in most surface-water-derived drinking waters. These mutagens are formed from widespread, naturally occurring precursors, such as humic substances, although other substances, especially amino acids may be involved. Most of the chlorination-derived mutagens identified account for little of the mutagenicity of drinking water. However, one mutagen, MX, is highly potent and may have a significant contribution. Its occurrence and toxicity need full evaluation. Other oxidants/disinfectants, such as ozone and chlorine dioxide, can also generate mutagens but these are likely to differ from those produced by chlorination. Granular activated carbon is effective in removing chlorination-derived mutagens but less effective for precursors. Dechlorinating agents, such as sulphur dioxide, can eliminate some of the mutagens produced by chlorination. The bacterial mutagenicity test cannot give information on the actual risks to health posed by the mutagens. Such information could arise from follow up work on identified major mutagens and from application of other bioassays more indicative of effects in man. Consequently, at the present time it is difficult to justify major changes to treatment practice aimed solely at controlling mutagenicity.

Nitro and chloro-benzenic compounds, which are widely used in dye industries, have been associated recently with groundwater contamination. Because of their potential toxicity and for taste and odor considerations, three main actions were decided to solve the problem. First, to follow the advance of pollution toward the wells, samples were collected automatically and analyzed using GC-MS. Results indicate that o-chloronitrobenzene was the main pollutant in concentrations ranging from 10 to 20,000 μg/1. Second, to monitor the drinking water quality, an on-line spectrophotometer was used to measure the optical density at 254 nm at the inlet and outlet of the plant. Third, the feasibility of using the O₃/H₂O₂. combination was determined at a 450 1/h pilot plant. Reduction of chloronitrobenzenes from 1.9 mg/1 to less than 20 μg/1 could be reached by the application of 8 g O₃/m3 and 3 g H₂O₂/m3 with a 20-minute contact time. To avoid an eventual bacterial regrowtn in the network due to biodegradability of the oxidation by-products, sand and GAC filtration were tested after oxidation. An evaluation of the costs of these different treatments is also presented.

The feasability of the combined use of ozone and hydrogen peroxide in surface water preozonation and in the ozonation of pretreated water was evaluated in relation to H₂O₂ dosage, time of H₂O₂ addition, O₃ dosage TOC, UV₂₅₄ absorption, formation of oxidation by-products, trihalomethane precursor removal and adsorption on activated carbon in comparison with the use of ozone as such, Although in all cases a small but consistently better UV₂₅₄ removal was observed though the combined use of ozone and hydrogen peroxide, the beneficial effects for other parameters were limited or non existent, especially within the range of ozone doses applied during surface water preozonation (< 2 mg/L). Therefore, the combined application of ozone and hydrogen peroxide seems to have little advantage over the use of ozone alone in the treatment of this type of surface waters.

Two methods widely applied for isolating PAH from surface water have been compared: solvent extraction using cyclohexane and solid surface extraction. Higher recoveires were obtained through solvent extraction, while the reproducibility for both methods was similar. In spite of the higher costs solvent extraction was selected for further use. Results obtained on surface water samples were strongly influenced by the presence of suspended material. PAH were shown to be mainly associated with the larger suspended particles which are removed easily through sedimentation in impoudment reservoirs. The results obtained stress the need for clearly identifying the sample type (filtered or not) and the sampling point (before or after impoundment) when performing this analysis for evaluating water quality in relation to legal requirements.

The waste from the industry of extraction of ETHANOL from wine and its sub-products, constitute a serius problem of contamination for the continental waters where they are — dumped.In this paper we present the results obtained from an investigation into the organic micropollutants in this waste, their evolution and behaviour, in a process of purifying trough accelerated anaerobic fermentation. The results show a high degree of purification which reaches, for some standard parameters, more than 95%, and for the overall total of the micropollutants reaches values of 99,9%.

Polyethoxylated C12–C15 alcohols, nonylphenols and ((nonylphenoxy) polyethoxy)acetic acid and their brominated derivatives were identified in the River Llobregat and in the tap water of Barcelona by GC/MS and FAB mass spectrometry. Whereas GC/MS is limited to those compounds with a low polyethoxylation degree, FAB mass spectrometry is a fast and simple technique to determine sufactants with a high range of oligomers present in the samples. We believe that both techniques are complementary. The source of these compounds are the dumps of surfactant industries and dyeing and textile processes. Their brominated derivatives are formed in the chlorination stages in the water works plant due to a high content of bromide ions in the upper course of the river.

The aim of our study was to determine the effects of a preoxidation with chlorine dioxide on the production of organohalogenated compounds (trihalomethanes, dichloroacetic and trichloroacetic acids) formed from the chlorination of different raw surface waters and of isolated aquatic humic substances. Samples of natural waters and of fulvic and humic acid solutions were oxidized for a reaction time of 24 hours with increasing doses of chlorine dioxide (from 0 to 2.5 mg of ClO₂ per mg of TOC), then heavily chlorinated (chlorine doses: 40–60 mg l−1, reaction time: 72 hours). The results obtained with laboratory experiments showed that surface waters consumed about 0.7 mg ClO₂/mg TOC after a reaction time of 24 hours and fulvic and humic acids about 1.6 mg ClO₂/mg TOC. For doses of chlorine dioxide corresponding to the above values of demands, the experiments showed that there was a significant decrease in the formation potentials of trihalomethanes (45–55%), of dichloroacetic acid (30–40%) and of trichloroacetic acid (40–60%) as well as in the chlorine demand during postchlorination (10–20%). Compared to chlorine, chlorine dioxide produced very small amounts of organohalogenated compounds. Furthermore, the production of chlorite and the concentration of organic matter (Total Organic Carbon and UV absorbance measurements) were also measured during our experiments.

High field proton NMR spectroscopy in DMSO-d6 solution is applied for structural analysis of main high molecular fractions of natural humus and waste lignin from kraft pulp mill. The spectra are similar in great part. Main differences appear in p-disubstituted benzene proton and -CH₂ -CO-proton signals which are absent in spectrum of waste lignin obviously due to chlorination. A new observation of 51 Hz 1:1:1 triplet in both spectra is discussed.

Between 0.25 and 1 percent of the adsorbable organic halogen in spent bleach liquors was shown to be bound to potentially bioaccumulable compounds. Chlorinated thiophenes, phenols and terpene derivates were identified in the lipophilic fraction.

14C-labelled benzo(a)pyrene (BaP) was added to three types of water samples a) bog water, b) lake water and c) artificial water. After equilibration the samples were chlorinated with NaOCl solution under buffered conditions. After 72 h BaP and degradation products were extracted consecutively with CH₂ Cl₂ at neutral pH then at acidic pH and finally by absorption to XAD-2. The extracts were subjected to fractionation by reverse-phase HPLC.In contrast to the artificial water about 20% of the reaction products could not be extracted from the humic water samples. This might either be due to formation of more water soluble degradation products in the presence of humic matter or strong complexation of these products to humus. On the other hand, no significant difference in the reaction product profile is. observed in the neutral CH₂ Cl₂ extract of neither of the three water samples, i.e. humus has no effect on the distribution of reaction products in this fraction.

This study compares the effects of different waste water treatments using sodium hypochlorite, chlorine dioxide and ozone on some chemical and biological parameters. The samples studied were obtained from an activated sludge treatment plant of the urban effluents of a large city and from a mixed urban and industrial waste sewage (treated only by sedimentation). A bacterial mutagenicity test (Ames test), microbiological examinations (coliforms, fecal streptococci and coliphages), determinations of the principal chemical parameters and of some organic micropollutants (polycyclic aromatic hydrocarbons - PAH -, and volatile haloderivatives - VHO -) were carried out on the effluents both before and after disinfection. The results showed that all treated and untreated samples were not mutagenic and that only ozone was able to reduce the concentration of all the examined organic micropollutants. Treatment with hypochlorite decreased only PAH concentration, even though their halogenated derivatives and trihalomethanes were formed. Trihalomethanes were found generally in lower concentrations after disinfections with chlorine dioxide. Hypochlorite showed a good bactericidal activity, but a little viricidal activity, whereas chlorine dioxide and ozone had a very good disinfectant activity both on bacterial and viral forms.

Mathematical models in the marine environment can be grouped into several classes. These models may be splitted into physical, chemical and toxicological models. Further they may be classified by their geographical extension, their accuracy and/or amount of input data needed. This paper gives a brief discusson of the main classes of models.We have used three different models to investigate transport and fate of chemicals in the aquatic environment. In this paper the models FEQUM, EXAMS and QWASI are presented, their characteristics explained and a comparison of the models is made.The three models have been applied to the Norrsundet area. Norrsundet is a heavily polluted bay on the eastcoast of Sweden. The pollution is mainly due to a kraft mill located in the area. The models were calibrated using data on chloroform in wastewater, and tested on four chlorophenolics. All models give satisfactory results for the compounds investigated exept for Tetrachlorocatechol. Correlation coefficients between calculated and measured concentrations vary from 0.86 to 0.97. The results obtained for tetrachlorocatechol are probably due oxidition of TeCC before reaching the first compartment.

A review is presented of some basic concepts and recent achievement concerning the modelling of transport of organic substances in groundwater. Organic pollutants are subjected to complexe physical, chemical and biological transformations while moving through the groundwater layers, such that no individual possesses a complete understanding of all the processes involved, and consequently the study of this subject becomes an interdisciplinary field of research. Recently, a large number of new developments have emerged giving new insight into processes as hydrodynamic dispersion, sorption, biodegradation and immiscible flow. It is concluded that considerable work has been done with respect to modelling of organic pollutant transport in groundwater, but a need to further developments remains necessary in order to put an effective stop to the very serious deterioration of the groundwater reserves.

The need to have an accuracy knowledge about concentrations exposure and fate of surfactants in the Comunidad de Madrid rivers determined the construction of a water quality model that was able to simulate the behaviour of some of them.This model has been used in two main ways,to get a better knowledge and to select the investment in waste water treatment plant that would fulfill the water quality goals planned in the surface watersIn adition to the normal constituents in water quality studies has been modeliced an anionic surfactant, linear alkylbenzene sulfonate (LAS). this paper show a general overview to this model.The model construction has been based on U.S. Environmental Protection Agency computer program QUAL2E,being very helpful the cooperation,advising and cospo.(Detergents Research Association Barcelona), and the Comite Conjunto Hispano Norteamericano para la Cooperacion Cientifica y Tecnologica.

Mathematical models for evaluating the dynamic behaviour of anthropogenic substances in aquatic systems (MASAS) are being developed and implemented on a personal computer. The MASAS system will allow the user to construct models of increasing complexity for lakes, rivers, and groundwater aquifers, and to build up compound and system libraries. In this paper, the general concept of the MASAS system is described and a summary of the present status of implementation is given.

In environmental analytical chemistry chemometric tools are used in quantitative rather than in qualitative analysis. In this paper chemometric concepts and methods for the identification and structure elucidation of organic compounds are discussed. Attention is focussed on the application of computer-aided library search and artificial intelligence to the interpretation of spectrometric and chromatographic data, whether or not combined. Library search systems for mass spectra as well as for combined ultraviolet spectra and HPLC retention data were developed based on mathematical statistical models of the reproducibility of the data involved. A pilot version of an expert system for structure analysis of organic molecules was developed based on combined infrared and mass spectral data, using artificial intelligence and information theory. Here too, the significance of results is indicated by numerical (relative) probabilities. General concepts and results are presented.

Referring to recent experience concerned with the deterioration of marine ecosystems and degradation of their environmental qualities, it is urged that the problems of the future are identical with or they are based on the environmental problems of today. Environmental damages are caused by macropollutants as well as micropollutants, they may be irreversible by nature and irrevocable in their development. Confidence in the prevention of future problems is therefore closely related to the proper protection of the environment today. This prevention should be based on analysis and problem identification in their entirety, and methods of protection should concentrate on the sources of environmental impact — rather than on restorations and remedial actions at the level of environmental target systems.