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1 FEB Fresenius Environmental Bulletin founded jointly by F. Korte and F. Coulston Copyright by PSP Parlar Scientific Publications, Angerstr. 12, Freising, Germany. Production by MASELL Agency for Public Relations, Angerstr. 12, Freising, Germany All rights are reserved, especially the right to translate into foreign language. No part of the journal may be reproduced in any form- through photocopying, microfilming or other processes- or converted to a machine language, especially for data processing equipment- without the written permission of the publisher. The rights of reproduction by lecture, radio and television transmission, magnetic sound recording or similar means are also reserved. Printed in GERMANY ISSN

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3 FEB - EDITORIAL BOARD Chief Editor: Prof. Dr. H. Parlar Institut für Lebensmitteltechnologie und Analytische Chemie TU München Freising-Weihenstephan, Germany - parlar@weihenstephan.de Co-Editors: Environmental Analytical Chemistry: Prof. Dr. W. Fresenius Institut Fresenius GmbH, Im Maisel 14, Taunusstein, Germany Dr. D. Kotzias Commission of the European Communities, Joint Research Centre, Ispra Establishment, Ispra (Varese), Italy Environmental Biology: Prof. Dr. A. Piccolo Università di Napoli Frederico II, Dipto. Di Scienze Chimico-Agrarie Via Università 100, Portici (Napoli), Italy Prof. Dr. G. Schüürmann UFZ-Umweltforschungszentrum, Sektion Chemische Ökotoxikologie Leipzig-Halle GmbH, Permoserstr.15, Leipzig, Germany Environmental Chemistry: Prof. Dr. M. Bahadir Institut für Ökologische Chemie und Abfallanalytik TU Braunschweig Hagenring 30, Braunschweig, Germany Prof. Dr. M. Spiteller Institut für Umweltforschung Universität Dortmund Otto-Hahn-Str. 6, Dortmund, Germany Environmental Toxicology: Prof. Dr. H. Greim Istitut für Toxikologie und Umwelthygiene Lazarettstr. 62, München, Germany Prof. Dr. A. Kettrup GSF-Forschungszentrum für Umwelt und Gesundheit GmbH Ingolstädter Landstraße 1, Neuherberg, Germany Environmental Management: Dr. H. Schlesing Secretary General, EARTO, Rue de Luxembourg,3, 1000 Brussels, BELGIUM Prof. F. Vosniakos T.E.I. of Thessaloniki, Applied Physics Lab. P.O. Box 14561, Thessaloniki, Greece. FEB - ADVISORY BOARD Environmental Analytical Chemistry: K. Ballschmitter, D - K. Fischer, D - R. Kallenborn, N D.C.G. Muir, CAN - R. Niessner, D - K. Bester, D Environmental Biology: D. Adelung, D - A. Görg, D - F. K. Kinoshita, U.S.A G.I. Kvesitadze, GEOR - A. Reichlmayr-Lais, D R. Viswanathan, D Environmental Management: F.J. Carlin, Jr., U.S.A - E.B. Fitzpatrick III, U.S.A O. Hutzinger, D - L.O. Ruzo, U.S.A - U. Schlottmann, D P.J.M. Weusthof, NL Environmental Chemistry: J.P. Lay, D - J. Burhenne, D - S. Nitz, D D.L. Swackhammer, U.S.A. - R. Zepp, U.S.A. Environmental Toxicology: F. Bro-Rasmussen, DK - F. Coulston, U.S.A. - H. Frank, D H. P. Hagenmeier, D - D. Schulz-Jander, U.S.A. H.U. Wolf, D Managing Editor: Dr. G. Leupold Institut für Chemisch-Technische Analyse und Chemische Lebensmitteltechnologie, TU München Freising-Weihenstephan, Germany leu@weihenstephan.de Editorial Chief-Officer: Selma Parlar PSP- Parlar Scientific Publications - Angerstr.12, Freising, Germany parlar@psp-parlar.de - Production & Marketing Chief Manager: Max-Josef Kirchmaier MASELL-Agency for Marketing & Communication, Public-Relations Angerstr.12, Freising, Germany masell@masell.com - Abstracted/ Indexed in: Biology & Environmental Sciences, C.A.B. International, Cambridge Scientific Abstracts, Chemical Abstracts, Current Awareness, Current Contents/ Agriculture, IBIDS database, Information Ventures, Research Alert, Science Citation Index (SCI), SciSearch, Selected Water Resources Abstracts 699

4 CONTENTS ORIGINAL PAPERS LEVELS OF PERSISTENT ORGANOCHLORINE COMPOUNDS 701 IN HUMAN MILK FROM SEVERAL REGIONS OF SLOVAK REPUBLIC M. Veningerová, V. Prachar, J. Uhnák and J. Kovacicová MONITORING OF KEY EUTROPHICATION PARAMETERS AT THREE 706 INSHORE STATIONS OF STRYMONIKOS GULF, NORTH AEGEAN SEA N. Stamatis, D. Ioannidou and E. Koutrakis HISTORICAL PROFILE OF POLYCHLORINATED BIPHENYLS (PCBs) 711 IN AN ALPINE GLACIER S. Villa, V. Maggi, C. Negrelli, A. Finizio, E. Bolzacchini and M. Vighi A SURVEY OF ARSENIC LEVELS IN TAP, UNDERGROUND 717 AND THERMAL MINERAL WATERS OF GREECE M. Mitrakas ADSOPTION STUDIES OF 14 C LABELED ATRAZINE ON 722 MOROCCAN SOILS WITH DIFFERENT ORGANIC MATTER CONTENTS E.Mechrafi, M.Elazzouzi, A.Bouhaouss, A.Dahchour, C.Perrin-Ganier and M.Schiavon MODIFYING LEAD, ZINC AND CADMIUM BIOAVAILABILITY 727 IN SOIL BY APATITE AND EDTA ADDITION H. Grcman, J. Persolja, F. Lobnik and D. Leštan REMOVAL OF ARSENIC IN AQUEOUS SOLUTION 731 BY ELECTROCHEMICAL PEROXIDATION M. Arienzo, J. Chiarenzelli and R. Scrudato SORPTION BEHAVIOUR OF COPPER(II), ZINC(II) AND NICKEL(II) ON 736 FORMALDEHYDE CROSS-LINKED SACCHAROMYCES CEREVISIAE IMMOBILIZED ON PUMICE STONE M. Lale, Z. Temoçin and H. Bag LETTER TO THE EDITOR 741 GUIDE FOR AUTHORS 744 INDEX

5 LEVELS OF PERSISTENT ORGANOCHLORINE COMPOUNDS IN HUMAN MILK FROM SEVERAL REGIONS OF SLOVAK REPUBLIC M. Veningerová, V. Prachar, J. Uhnák, and J. Kovacicová Institute of Preventive and Clinical Medicine, National Reference Center for Pesticide Residues, Limbová 14, Bratislava, Slovak Republic SUMMARY The paper deals with monitoring the levels of persistent chlorinated insecticides and benzenes in mother milk in 10 districts of Slovakia. Special attention is paid to the intake of these compounds by the infants. Analyses of chlorinated pesticides showed considerable differences in their levels between the districts, the highest concentrations being recorded for DDE (0.181 mg.kg -1 in average, fat basis). Average concentration of ß-HCH was 5-fold that of γ-hch (0.026 and mg.kg -1 fat, resp.). The values found were compared to the No Observed Effect Levels values (NOELs). The average levels did not exceed the permissible levels (PL). Average daily intake of the chlorinated compounds via mother milk did not exceed the Acceptable Daily Intake (ADI), except for hexachlorobenzene. The intake of hexachlorobenzene in some districts exceeded the ADI value. KEYWORDS: mother milk, chlorinated pesticides, risk assessment, permissible level Irrespective of the many benefits of breast-feeding, this nutrition can, nevertheless, carry a health risk connected with the presence of hazardous organic contaminants entering human organism from the environment. Chlorinated pesticides and their metabolites and degradation products belong to this group. Current toxicological research brings in new information on compounds that, in spite of their long term limitation or ban, pose actual health risk for humans. There is new information on some of the persistent chlorinated compounds concerning their proven or suspected carcinogenic effect or endocrine disruptive effects (1, 2). Literature data as well as our own work shows exposition of the population to chlorinated insecticides and benzenes (1,3,4,5). The present study was aimed at evaluating their exposure to infant organism, determination of the average daily intake and the resulting health risk. The work was carried out by determining the levels of these compounds in the milk of mothers living in selected districts of Slovakia. MATERIALS AND METHODS INTRODUCTION Breast-feeding is very important for healthy growth of infants in the first months of their life. Apart from the high nutritional value and immunological factors, positive psychosocial aspects connected with this type of feeding are quite significant. Mother`s milk contains mainly immunoglobines, proteins, vitamins, trace elements, lactose, fat, and growth and development modulating components. All major nutrients in mother s milk have multiple functions as build-up units and source of energy for the child s growth. Many of them have specific protective functions from infections and allergy. Lipid fraction contains triacylglycerols, phospholipids, cholesterol and cholesterol esters. It is indispensable for the growth and development of infants because it supplies over 50 % of the energy needs and serves as the carrier for liposoluble vitamins and essential fatty acids. Samples: Samples of mother s milk were taken during the years 1998 through 1999 from professionally non-exposed volunteers from the general population. In total, 132 mother s milk samples were analysed for HCH isomers, pentachlorobenzene (PeCB), isomers of tetra-chlorobenzene (TeCB), trichlorobenzene (TCB), and dichlorobenzene (DCB). Samples, 100 ml each, were taken in the period between two and fifteen weeks after delivery. A questionnaire was completed with each of the volunteer mothers at sampling time. The questions related to the age, body height, body weight (before pregnancy and after delivery), eating and smoking habits, history of disease medicines used, etc. Milk samples were stored in specially cleaned teflon cap glass jars and deep freezed immediately after sampling to 28 C. Samples were taken in 10 model districts of Slovakia representing different degrees of industrial and agricultural activities (Fig. 1). 701

6 FIGURE 1 Map of Slovakia showing the sampling districts/localities BA-Bratislava, GA-Galanta, TN-Trencín, ZH-Žiar n/hr., PD-Prievidza, PP-Poprad, DK-D.Kubín, KK-Kežmarok, RS-R.Sobota, TV-Trebišov Chemicals: Standards of chlorinated benzenes and insecticides were purchased from Supelco SA, Gland, Switzerland, Merck Darmstadt, and Aldrich, Steinheim, Germany. All solvents and chemicals were pesticidegrade, purchased from Merck Darmstadt, and Aldrich, Steinheim, Germany. Isolation and determination: Isolation, identification and GC analysis for this study was based on previously published methods (3,5,6). RESULTS AND DISCUSSION Characteristics of the mothers included in the study The age of the mothers was between 18 and 40, the average age was Thirty eight per cent of the mothers were primiparae. The comparison of the Body Mass Index (BMI) of the mothers before pregnancy and after the delivery showed that after the delivery the BMIs were higher by 1.9 on average. For eating habits, most of the mothers indicated mixed food comprising meat, dairy products, vegetables, fish and poultry. Two per cent of the mothers indicated strictly vegetarian food, another 2 % were lactovegetarians. Active and passive smoking was indicated by 44.8 and 40.9 per cent of the mothers, resp., 44.1 per cent of the mothers lived in rural areas, 55.9 % in urban areas. Results of the analyses of chlorinated pesticides showed considerable differences in their concentrations in breastmilk between the regions (Tab. 1). From among the HCH isomers, the highest values were found for ß-HCH (ND-0.21 mg.kg -1, fat basis), the highest mean and median contents being found in the city of Bratislava (capital of Slovakia, characterised by high population concentration, intensive industrial activities including incineration plant for communal and industrial waste, and intensive traffic). Levels of γ-hch were considerably lower, the average concentrations ranging between ND-0.01 mg.kg -1 (fat basis). Concentrations of the α-hch were low i.e. within the order of 10-3 mg.kg -1. Concentrations of δ-hch were below the limit of detection. Relatively high levels of DDE (ND-1.31 mg.kg -1, fat basis) were found, the highest in three of the prevailingly agricultural regions (Trebišov, Prievidza and R. Sobota) and the lowest in Bratislava. The levels of DDT were also the highest in Trebišov. The ratio of average and median values DDE/DDT was 3.15 and 3.43 resp., which is in accordance with decreasing levels of the accumulated DDT. From among the chlorobenzenes investigated, only HCB was found in very high amounts, the concentrations ranging from ND-0.62 mg.kg -1 (fat basis). The highest average concentrations were found in the districts of Trebišov, Dolný Kubín, Trencín and Bratislava. Average levels of pentachlorobenzene and the isomers of di-, tri-, and tetrachlorobenzene ranged between and mg.kg -1 (fat basis). 702

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8 TABLE 2 Comparison of permissible levels with assessed concentration in mother milk [mg.kg -1 on fat] Compound Permissible level PL Safety factor SF Assessed level mean maximum 1,2-DCB PeCB HCB α-hch ß-HCH γ-hch total DDT From among the Slovak regions investigated, the highest concentrations of the contaminants under study were found in Trebišov, Prievidza and Rimavská Sobota. Comparison of the levels of chlorinated pesticides in the milk of mothers residing in rural and urban areas showed that the levels of HCB, γ-hch, DDE and DDT were higher for women living in rural areas, by a factor of 1.1 to 1.6 in average. These findings are in accordance with what had been expected, owing to the fact that those compounds had been intensively used in agriculture in the past. On the basis of average concentrations of the compounds studied, daily intakes of chlorinated pesticides for newborn babies were calculated. An estimated daily consumption of 800 ml of mother`s milk was taken as basis for the calculation. The other parameters needed for the calculation were the actual values at sampling. The calculated daily intakes were compared to the Acceptable Daily Intake (ADI) values (9). For the infants, the average daily intake of chlorinated compounds from milk of mothers residing in Slovakia did not exceed the respective ADIs, except for HCB, for which the ADI was exceeded in Trencín and in Trebišov (137.5, %, resp). However, it should be noted that in all the regions investigated there were individual cases of high HCB levels. Thus, there may be individual cases of relatively high daily intakes of HCB in young babies. To estimate the potential effect from the intake of the determined levels of the compounds under study, the modified approach based on the NOEL value (7,10) has been employed. The permissible level (PL) of a specific compound in daily diet, expressed as mg of the compound per kg of the daily diet, can be derived from the NOEL value, body weight of the consumer, weight of the food consumed, and a safety factor. The permissible levels of chlorinated pesticides calculated according to the procedure (7, 8) using the safety factors of 1000, 100, and 10 are given in Table 2 and are compared to the average and maximum levels found in mother milk. Table 2 shows that the average levels of all compounds found in the study did not exceed the PL at safety factor of 100. On the other hand, maximum levels of HCB and total DDT comply with the respective PLs only when safety factor of 10 is applied. However, considering the definition of NOEL, this does not necessarily implicate adverse effect on human health. The calculated values of daily intake of chlorinated pesticides from mother`s milk were compared with the calculated daily intakes from baby formulas. The HCB, total DDT and ß-HCH levels found in baby formulas were lower than those in mother milk by a factor of 6.4 to 8.8, whereas the levels of γ-hch were higher than in those mother`s milk. Our results concerning the chlorinated compounds were compared with the values found by authors in neighbouring countries. Gajdušková et al. (11) found HCB, gama-hch and DDE values comparable to our findings in mother`s milk of women residing in Brno region (Czech Republic): , < , and mg.kg -1 fat, resp. The mothers in study (11) were primiparae and secundiparae. Schoula et al (12) reported higher levels in primiparae mothers living in three regions of the Czech Republic, i.e mg.kg -1 fat DDT and mg.kg -1 fat HCB. The levels of ß-HCH were comparable to ours. German authors (13) reported average contents of total DDT, HCB, ß-HCH and γ-hch in mother s milk in 1999 to be 0.551, 0.218, 0.075, and mg.kg -1 fat, resp. The levels were compared with maximum levels permitted in cow's milk in European Community and permitted maximum levels in infant food according to the German dietary regulation of Fürst et al. (14) reported results of over 1400 individual mother milk samples of women mostly living in North Westphalia, a federal state in Germany. Average contents of DDE, DDT, HCB, γ-hch and ß-HCH found in 1991 were 0.504, 0.027, 0.177, 0.006, and mg.kg -1 fat, respectively. 704

9 The authors compared their calculated daily intakes with NOEL values. In those cases where the analysed contaminant levels in mother`s milk exceed the permissible levels calculated with the safety factor of 10, the authors recommend to reduce temporarily the amount of breast-fed milk. The results of the analyses of chlorinated pesticides in two regions in Ukraine (Gladen et al., 15) showed higher contents than those reported by most EU authors. Results for 197 analysed samples showed median values of HCHs and DDE mg.kg -1. CONCLUSIONS The levels of chlorinated pesticides found in mother milk of Slovak women are in general comparable and in most cases lower than those found in the neighbouring countries. Considerations on possible adverse effects on the organism of infants are therefore not justified. In individual cases of high HCB contents, where the daily intakes exceed the ADI, the health status of the infants should be monitored individually and this aspect should be also considered. ACKNOWLEDGEMENT The authors express their thanks to Marta Svrcková, Juliana Koglerová and Viera Mikulášová for technical assistence. The help of colleagues from State Health Institute who performed the sampling is also gratefully acknowledged. REFERENCES (1) Dewailly E., Ayotte P., Laliberté C., Weber J.P., Gingras S., Nantel A.J.: Polychlorinated biphenyls and dichlorodiphenyl dichloroethylene concentations in the breast milk of women in Quebec. Am. J. Public Health, 86, 9, 1996, (2) Colborn T., Vom Saal F. S., Soto A. M.: Developmental effects of endocrine-disrupting chemicals in wild-life and humans. Environ. Health Perspect. 101,1993, (3) Prachar V., Veningerová M., Uhnák J.: Levels of polychlorinated biphenyls and some other organochlorine compounds in breast milk samples in Bratislava. Sci. Tot. Environ. Suppl. 1993, 1993, (4) Rogan W.J.: Pollutants in breast milk. Arch. Pediatr. Adolesc. Med., 150, 1996, (5) Uhnák J., Veningerová M., Prachar V.: Contamination of human milk by persistent chlorinated compounds. Cs. Hyg. 38, 2, 1993, (6) Prachar V., Veningerová M., Uhnák J., Kovacicová J.: Polychlorinated biphenyls in mother milk and adapted cow's milk. Chemosphere, 29, 1, 1994, (7) Deutsche Forschungsgemeinschaft: Rückstände und Verunreinigungen in Frauenmilch, Mitteilung XII der Kommission zur Prüfung von Rückständen in Lebensmitteln. VCH, Weinheim (1984) 99 pp. (8) Prachar V., Uhnák J., Veningerová M.: Contribution to the evaluation of organochlorine compounds in human milk. Hygiena, 41, 1, 1996, (9) International Programme on Chemical Safety, WHO, 99,1, 1998, Geneva, Switzerland (10) Chlorobenzenes other than hexachlorobenzene. Environmental health criteria, 128, WHO IPCS Series Geneva, (11) Gajdusková V., Ulrich R., Ledvinová J., Anton M., Kopecný J.: Concentrations of polychlorinated biphenyls and chlorinated pesticides in human breast milk. Centr. Eur. J. Public. Health, 4, 2, 1996, (12) Schoula R., Hajslova J., Bencko V., Poustka J., Holadova K., Vizek V.: Occurence of persistent organochlorine contaminants in human milk collected in several regions of Czech Republic. Chemosphere, 33, , (13) v. Mühlendal K.E., Otto M., Manz F.: Pesticides in baby food: a European issue. Eur. J. Pediatr. 155, 1996, (14) Fürst P., Fürst Ch., Wimer K.: Human milk as a bioindicator for body burden of PCDDs, PCDFs, organochlorine pesticides and PCBs. Environ. Health Perspect Supplements, 102, 1, 1994, (15) Gladen B.C., Monaghan S.C., Lukyanova E.M., Hulchiy O.P., Shkyryak-Nyzhnyk Z.A., Sericano J.L., Little R.E.: Organochlorines in breast milk from two cities in Ukraine. Environ. Health Perspect, 107, 6, 1999, Received for publication: February 02, 2001 Accepted for publication: August 22, 2001 CORRESPONDING AUTHOR Marta Veningerová Institute of Preventive and Clinical Medicine National Reference Center for Pesticide Residues Limbová Bratislava - SLOVAK REPUBLIC Fax: veninger@upkm.sk FEB/ Vol.10/ No.9/2001 pages

10 MONITORING OF KEY EUTROPHICATION PARAMETERS AT THREE INSHORE STATIONS OF STRYMONIKOS GULF, NORTH AEGEAN SEA N. Stamatis, D. Ioannidou and E. Koutrakis N.AG.RE.F., Fisheries Research Institute (F.R.I.), N. Peramos,? avala, Greece SUMMARY Dissolved nutrients, chlorophyll-a, salinity and temperature were measured at three inshore stations of Strymonikos Gulf in order to monitor the eutrophication process. Monthly samplings were carried out for the period from December 1997 to June High mean concentrations of dissolved inorganic nitrogen (144.3 µg l -1 ), soluble reactive phosphorus (12.4 µg l -1 ) and dissolved silicon (716.5 µg l -1 ) classified the inshore Strymonikos Gulf within the eutrophic Greek marine areas. Agricultural run-off transferred by Strymon River was identified as the main source of the nutrients. Chlorophyll-a mean values ranged from 0.24 to 1.6 µg l -1, those of temperature and salinity between 8.8.and 29.1 o C and from 3.3 to 37.1 ppt, respectively. The eutrophication effect is spatially limited to inshore areas and it is not detectable at the offshore areas of Strymonikos Gulf. KEYWORDS: coastal eutrophication, nutrients, chlorophyll-a, temperature, salinity. INTRODUCTION The Mediterranean Sea is generally considered as oligotrophic due to its relatively low nutrient content [1]. However, coastal areas of the Mediterranean encounter increasing eutrophication caused mainly by anthropogenic influences. The Strymonikos Gulf, located at the Northern Aegean Sea (Eastern Mediterranean), is the potential final recipient of nutrients originating from agricultural and industrial activities as well as from urban population. The total catchment of Strymonikos Gulf is estimated at ca km 2. Main sources of nutrients are considered to be the run-off of Strymon, Richios and Mavrolakas rivers and the municipal effluents of Asprovalta, Stavros and Olympiada towns. From the three rivers flowing into the Strymonikos Gulf, Strymon is by far the biggest with a mean water flow of 60 m 3 /s. All coastal towns are mainly summer residences with more than inhabitants during summer. From this point of view, Strymonikos Gulf is a particularly interesting ecosystem for the study of eutrophication. Considering that this coastal zone has not been adequately studied, the work presented herein is a first attempt to (1) present the seasonal variation of key eutrophication parameters at three inshore stations of Strymonikos Gulf, (2) classify the trophic state of inshore Strymonikos Gulf and (3) compare these results with data from other Greek coastal areas. STUDY AREA AND METHODS Sampling was done at three stations (St1, St2, St3) of Strymonikos Gulf in monthly intervals from December 1997 to June All samples were taken with a Ruttner 1l water sampler (Hydrobios, Kiel). Temperature and salinity were measured by a portable salinity meter (LF 340/WTW) equipped with a 20 m long cable. Sampling station 1 (10 m deep) is located about one nautical mile from the delta area of Strymon River (Fig. 1). From this station two sub-samples were taken in order to measure surface (St1a) and deep (St1b) water features. Sub-sample 1a comprised of a mixture of 5 l of water, each collected from meters 0-4 and sub-sample 1b comprised of a mixture of 5 l collected from meters 5-9. Temperature and salinity at this station were measured at 1 meter intervals. Sampling station 2 is located close to the town Stavros and about 1 n. mile distance from the river Richios. Sampling station 3 is located close to the town Olympiada and the river of Mavrolakas. From both stations, only surface water samples (1 m depth) were obtained from a distance of 10 m from the coast. 706

11 Chemical analyses of the water samples filtered through Whatman GF/C filters (0.45 µm) were performed for N-NO 3, N-NO 2, N-NH 4, P-PO 4 and Si-SiO 2 by the methods of the Grasshoff s manual [2]. For the determination of chlorophyll-a the spectrophotometric absorbance of 90 % acetone extracts was measured [2]. The sum of N-NO 3, N-NO 2 and N-NH 4 gives the dissolved inorganic nitrogen (DIN) and the P-PO 4 corresponds to soluble reactive phosphorus (SRP). A Beckman Model DU-65 spectrophotometer was used for the absorbance measurements and all chemical reagents used were pro analysi (Merck, Riedel de Haen). FIGURE 1 - Map of the study area and the sampling stations. N higher than those measured by known eutrophic Greek areas like Kavala [3], Thermaikos [4] and Saronikos Gulfs [5, 6, 7]. Higher values of DIN were recorded in the period of high precipitation and river flow, i.e. winter and spring, as compared to summer and autumn (Fig. 2d). The most important form of DIN consisted of nitrate nitrogen (84.6 %), followed by ammonium (11.9 %) and nitrite nitrogen (3.5 %). Both results indicate that the main origin of nutrients is the agricultural run-off. The frequency distribution of D?? values is shown in Fig. 3a. Mean values of SRP were much higher at the station 1a (12.4 µg l -1 ) as compared to the other three stations (6.2 µg l -1 at each 1b, 2 and 3). SRP values in the three stations fluctuated during the whole sampling period without an obvious seasonality (Fig. 2e) and are at the same levels with those of Kavala [3], Thermaikos [4] and Saronikos Gulfs [5, 6, 7]. The frequency distribution of SRP values is shown in Fig. 3b. Mean values of dissolved silicon were higher in stations 3 ( µg l -1 ) and 1a (825.9 µg l -1 ) than those of stations 1b (387.1 µg l -1 ) and 2 (366.5 µg l -1 ). All mean concentrations of dissolved silicon in Strymonikos Gulf were higher than those measured in Thermaikos Gulf [4]. Seasonal variation of dissolved silicon concentrations displayed peaks, particularly in stations 1a and 3, during winter and spring (Fig. 2f). During the same sampling period, nutrient mean concentrations [C] at offshore areas of Strynonikos Gulf were measured at significantly lower levels (C [DIN] < 21.3 µg l -1, C [SRP] < 2.0 µg l -1, and C dissolved silicon < 30.0 µg l -1 )[8]. These values demonstrate that the offshore area of Strymonikos Gulf is not an eutrofic zone. RESULTS AND DISCUSSION Nutrients Seasonal variation of N-NO 3, N-NO 2, N-NH 4, DIN, SRP and Si-SiO 2 at the stations 1a, 1b, 2 and 3 of Strymonikos Gulf is shown in Fig. 2a-f. Mean values of DIN were by two times higher at stations 1a and 3 than at stations 1b and 2. Mean values of DIN were 144.3, 60.2, 51.8 and µg l -1 at stations 1a, 1b, 2 and 3, respectively. Mean values of DIN in inshore water of Strymonikos were at the same level or slightly N:P atomic ratio in open sea is close to 16:1 (Redfield ratio) [9]. Lower N:P values may indicate anthropogenic influences and in eutrophic conditions, nitrogen may act as a limiting factor. Higher N:P values may indicate phosphorus as a possible limiting factor [10]. Mean values of N:P atomic ratio in Strymonikos Gulf were relatively high (36.8) indicating possible phosphorus limitation of primary production. Chlorophyll-a Chlorophyll-a mean values were higher in stations 1a (1.6 µg l -1 ) and 3 (0.9 µg l -1 ) as compared to the stations 1b (0.24 µg l -1 ) and 2 (0.62 µg l -1 ) (Fig. 4a). The higher concentrations of chlorophyll-a in stations 1a and 3 compared to stations 1b and 2, might be attributed to the higher concentrations of nutrients. Nevertheless, the highest value (11.1 µg l -1 ) was measured in station 3, in January Figure 4b shows the frequency distribution of chlorophyll-a. 707

12 FIGURE 2 a) - f) Seasonal variation of nutrient concentrations at three stations of Strymonikos Gulf. µg N-NO 3 /l a ) St 1a St 1b St 2 St 3 µg N-NO 2 / l b) µg N-NH 4 / l µg SRP / l 0 0 D J F M A M J J A S O N D J F M A M J D J F M A M J J A S O N D J F M A M J c ) 800 d) D J F M A M J J A S O N D J F M A M J e ) µg DIN / l µg Si-SiO 2 / l 0 D J F M A M J J A S O N D J F M A M J f) D J F M A M J J A S O N D J F M A M J D J F M A M J J A S O N D J F M A M J FIGURE 3 - Frequency distribution of a) TIN and b) SRP at inshore water of Strymonikos Gulf. FIGURE 4 - a) Seasonal variation of chlorophyll-a in surface water layer at three stations of Strymonikos Gulf and b) Frequency distribution of chlorophyll-a in inshore water of Strymonikos Gulf. Count TIN (µg l -1 ) n=76 x= a) µg chl-a /l a) St1a St2 St3 D J F M A M J J A S O N D J F M A M J Count SRP (µg l -1 ) n=76 x= b) Count b) Chl-a (µg l -1 ) n=57 x=

13 FIGURE 5 - Vertical mean seasonal variation of a) temperature (in o C) and b) salinity (in ppt) at sampling station 1. a ) b ) Depth / m SPR 99 WIN 99 AUT 98 SUM 98 SPR 98 WIN Chlorophyll values observed in the inshore area of Strymonikos Gulf are comparable to those observed in other eutrofic coastal areas, namely near the outflow of Evros River, in the Kavala Gulf, and in the middle part of Thermaikos Gulf [4], [11]. Chlorophyll-a values were generally higher during winter and spring than those in summer and autumn (Fig. 4a). The positive correlation (r = 0.48, n = 57) was found only between chlorophyll-a and the SRP values, and the high values of the N:P ratio have shown that phosphorus may constitute a major limiting factor in the increase of phytoplankton and eutrofication in the inshore Strymonikos Gulf. Temperature and Salinity Temperatures in the surface water layer ranged from 8.8 to 27.4? C at St1, 9.9 to 29.1? C at St2 and 10.9 to 28.8? C at St3. Salinity in the surface water layer ranged from 3.3 to 32.3 ppt at St1, from 10.2 to 37.1 ppt at St2 and from 10.9 to 35.3 ppt at St3. Temperature and salinity values are comparable to those detected in other estuarine systems of the Northern Aegean Sea [11]. The mean values of the temperatures of the surface layer of the station 1 (16.2? C) were lower than that of either station 2 (17.8? C) or 3 (18.1? C). This effect can be explained by the presence of cold, low salinity water masses from the Strymon River at station 1. Mean salinity values in the surface layer of the stations 1, 2 and 3 were 16.1, 31.7 and 28.8 ppt, respectively. Figure 4 shows the vertical distribution of the mean seasonal values of temperature and salinity in the water column at station 1. The highest variations of the mean seasonal values for the temperature (up to 3.4? C) and the salinity (up to 25.9 ppt) at station 1 were observed at the depth of 1 m, where the stratification of low and high salinity (density) waters occurs. CONCLUSIONS Based on the results of this study inshore water of Strymonikos Gulf can be classified as eutrophic. Nutrient concentrations and chlorophyll values together with temperature and salinity gradients showed that inshore water of Strymonikos Gulf seems to be affected principally from the Strymon River and to a lesser extent from the rivers Mavrolakas and Richios as well as from the coastal towns of Asprovalta, Stavros and Olympiada. High nutrient values were measured during the seasons of high precipitation, i.e. winter and spring. In addition, high percentage of N-NO 3 in DIN indicated agriculture as the main nutrients source. The results of this study indicated that monitoring programs provide useful information for the assessment of water quality and the management of a specific coastal zone. However, in the case of Strymonikos Gulf further research is needed in order to understand the causes and the effects of eutrophication and to make specific recommendations towards the protection of this coastal ecosystem. ACKNOWLEDGEMENTS We are grateful to the European Union and to the Greek Ministry for Environment for funding this investigation in the frame of program LIFE. Thanks are also due to Dr. S. Orfanidis for constructive comments on the manuscript. 709

14 REFERENCES 1. Krom, M. D., Kress, N., Bremmer, S. and Gordon, L. I., Limn. Oceanogr. 36, 424 (1991); 2. Grasshoff, K. (ed), Methods of seawater analysis, Verlag Chemie GmbH, D-6940 Weinheim (1983); 3. Sylaios, G., Ioannidou, D., Stamatis, N. and Kallianiotis, A., Proc. 6 th Hel. Symp. Oceanorg. & Fish. 2, 424 (2000); 4. Nikolaidis, G. and Moustaka-Gouni, M., Fresenius Envir. Bull. 1, 250 (1992); 5. Ignatiades, L., Karydis, M. and Vounatsou, P. Mar. Poll. Bull. 24, 238 (1992); 6. Karydis, M., Environ. Monitor. Assess. 41, 233 (1996); 7. Kitsiou, D., Karydis, M., J. Cost. Conserv. 4, 35 (1998); 8. Stamatis N. and Ioannidou D., Spatial and temporal distribution of nutrients in the whole area of Strymonikos and Ierissos Gulfs, In: Description of the coastal zone of Strymonikos and Ierissos Gulfs, E. Koutrakis, E. Lazaridou (eds). NAGREF-Fisheries Research Institute, Greek Biotope- Wetland Centre, N. Peramos, Kavala, Greece, , (1999); 9. Redfield, A. C., Ketchum, B. H. Richarrds, F. A. (eds.), The influence of organisms on the composition of seawater. In the sea, ideas and observations on progress in the study of the seas, Vol. 2, N. M. Hill (ed.) New York: Interscience, (1963); 10. Ryther, J.H. and Dunstan, W.M. Science 171, 1008 (1971); 11. Nikolaidis, G., Moustaka-Gouni, M. and Tryfon, E. Fresenius Envir. Bull. 5, 9/10 (1996). Received for publication: December 15, 2000 Accepted for publication: October 20, 2001 CORRESPONDING AUTHOR N. Stamatis N.AG.RE.F. Fisheries Research Institute (F.R.I.) N. Peramos,? avala - GREECE Phone: Fax: fri@mail.otenet.gr FEB/ Vol.10/ No.9/2001 pages

15 HISTORICAL PROFILE OF POLYCHLORINATED BIPHENYLS (PCBs) IN AN ALPINE GLACIER Villa S., Maggi V., Negrelli C., Finizio A., Bolzacchini E. and Vighi M. Dept. of Environmental and Landscape Science, University of Milano Bicocca, Milano, Italy SUMMARY An ice-core, drilled on Lys Glacier (Italian Alps), was analysed to determine PCB concentration. Contamination was characterised by low chlorinated congeners (di-, triand sometimes tetra- chlorobiphenyls) for all the investigated periods. The historical trend indicates the maximum concentration occurring in the early 1980's. These results are highly correlated to PCB technical mixture burden and physical-chemical properties. The role of temperature on PCB environmental fate is highlighted. High mountains can be considered to be a cold condenser. KEYWORDS: PCB, Log Koa, ice core, historical trend, high mountain, long range transport INTRODUCTION Persistent Organic Pollutants (POPs) are long-lived organic compounds, that can travel long distances in the atmosphere very far from emission sites, reaching remote areas as well as polar regions [1, 2, 3, 4]. The role of temperature on global transport patterns has been highlighted in describing cold regions as POP condensers [5]. A similar role was hypothesized for high mountains by Calamari et al. [6] and confirmed by many authors [7, 8, 9]. Mountain glacier ice cores have been widely used for studying historical trends of atmospheric depositions [10, 11], but very little research has been done on POPs, except a recent study on chlorinated pesticides in a temperate Canadian glacier and another study on the Lys Glacier [12, 13]. Changes in environmental release of POPs due to emission control or to remediation of old sources, will show up first in the atmosphere [14]. In this context, the Alps, close to European emission sites, may provide the opportunity to study long-range and local patterns of POP distribution. MATERIALS AND METHODS Sampling area and ice core dating The Lys Glacier, on the Monte Rosa massif (Figure 1), was chosen for a detailed reconstruction of the climatic and anthropogenic influences of the last 50 years. An 80-m ice core was drilled at 4,250-m a.s.l. on the Colle del Lys, Monte Rosa, Italian Alps. The density profile during drilling operations shows the close-off depth to be about 40 m. Major conductivity spikes are related to high acidic anthropogenic events. The 1977 Saharan dust deposition event has been clearly identified at a depth of 48 m, and used with the 1963 tritium thermonuclear bomb tests as a maximum to set-up a depth/age curve spanning the last 40 years. Thus, the average annual accumulation rate can be calculated as 1.7 m w.e. y -1 (± 0.10). A total of ten samples were obtained and each of them represents a period of three years, except for the two oldest samples, which represent five years of precipitation each. The sample volume ranged from 560 to 1,000 ml. Due to the high volume of the ice core samples and the number of determinations performed on each sample, it was impossible to analyse larger volumes. Chemical analysis Liquid-liquid extraction was applied for recoveries of the surrogates (10 ng for individual pesticides in methanol were added to 1 L of Milli Q grade water), which were prepared and extracted with pesticide grade hexane (100 ml) in a liquid-liquid extractor. To minimize re-equilibrium of the pesticides with the atmosphere, the samples were extracted with pesticide grade hexane as soon as the last bit of ice melted. The extract, concentrated by Rotavapor to 1 ml, was charged on a silica gel (1g) column and eluted with 9 ml of n-hexane. The hexane extracts were evaporated under gentle N 2 flux and analyzed by capillary gas chromatography (Perkin-Elmer mod. 8500) with 63 Ni electron capture detection (carrier gas He, 350 C) on a 30 m X 0.25 mm (0.25 µm film) DB-35 MS (J&W) column. 711

16 FIGURE 1 - Map of the studied area. TABLE 1 - Detection limits (pg/l) for the analysed PCB congeners. Congener chlorination class pg/l Di 280 Tri Tetra Penta Hexa Hepta Nona 60 FIGURE 2 - PCBs contamination trend from 50 to 96 in the Lys glacier (reported in pg/l). pg/l years hepta-cb hexa-cb penta-cb tetra-cb tri-cb di-cb 712

17 Oven temperatures were: 100 C (1 min), from 100 to 150 C (30 C/min), from 150 to 230 C (4 C/min) isothermal 4 min, from 230 to 280 C (4 C/min) isothermal 15 min. The selected congeners were PCB 8 (di), 15, 17, 18, 22, 28, 31, 33 (tri), 44, 49, 52, 64, 66, 70, 74 (tetra), 90, 95, 101, 105, 110, 118 (penta), 132, 138, 149, 153 (hexa), 170, 180, 190 (hepta), 194 (nona). The mean recovery was 85% and the reproducibility was calculated by means of a triplicate analysis giving an overall error of 10%. Due to the low amount of available samples, the detection limits are relatively high, inversely proportional to the degree of chlorination for the congeners (Table 1). RESULTS AND DISCUSSION The results, obtained from the ice core samples of the Lys Glacier, are shown in Figure 2. The 's sample was lost during analysis. The PCB fingerprint for Lys Glacier is highly characterised for the period under study by the less chlorinated congeners (di-, tri- and, occasionally, tetra-chloro biphenyls). The historical trend shows the maximum concentration in the early 1980's and the lowest concentration in the oldest as well as the most recent samples ( 93-96). The contamination levels are, in general, comparable with other data reported for ice and snow [3, 15]. Historical trend Historical data on the global production, usage and release of polychlorinated biphenyls (PCBs) are needed for interpreting the historical contamination levels in remote areas. Today, emissions of PCBs into the atmosphere may occur as a result of different processes, namely: primary anthropogenic emissions as a result of the intentional production and use of PCBs, volatilisation of PCBs from environmental reservoirs (e.g. sea-air gaseous exchange) and unintentional formation of PCBs (e.g. from waste incineration) [16]. The areas surrounding the Lys Glacier (Germany, France, Italy, Switzerland and Austria) are characterised by uniform PCB emissions [17]. It can be hypothesised, on the basis of Lavanchy's evidence [18], that the Lys ice core record reflects the emission of western Europe. Data on the historical production of various technical mixtures of PCBs by major producers have been compiled [19, 20]. These data indicate that the highest emissions occurred at the end of the 1960 s, followed by a decline as a consequence of restrictions on production and use. On the contrary, the PCB trends, recorded in Lys Glacier, show the maximum concentration in the early 1980's, about ten years after the emission peak. This delay seems to characterize all remote area trends. Indeed, different temporal profiles were identified in relation to the distance of the sampling area from emission sources: lower concentrations, delayed and less marked trends characterise remote or rural areas [21, 22, 23, 24, 25]. Moreover, production data has been coupled with the chemical composition of various mixtures [26, 27] to estimate the historical production of individual isomers and congeners. The comparison between the results and the environmental loads shows that the congeners, detected in the ice samples, are the most representative of technical mixtures (Aroclor 1242, 1248, 1254, 1260). High mountain fingerprint Blais and co-workers [8] highlighted different fingerprints in function of altitude: with increasing altitude, less chlorinated congeners become progressively more important in the contamination spectrum. The Lys data seem to fit well in this continuum: above 4,000 m only the lightest (di, tri and, sometimes, tetra) congeners are detected (Figure 3). Gregor and co-workers [28] found PCB concentrations inversely proportional to degree of chlorination for congeners in the Agassiz Ice Cup. This shows a strong similarity between the Pole and high mountain areas. This continuum shift in contamination fingerprint can be considered as experimental evidence of global distillation, which suggests a temperature dependent fractioning of PCB mixtures. Physical-chemical properties are fundamental in understanding long term spatial distribution patterns of POPs. The temperature dependence of the octanol-air partition coefficient (Log Koa), is a good indicator of the tendency of a compound to undergo long range transport. Moreover, this coefficient is recommended for describing partitioning of non-polar chemicals between air and soil, vegetation and aerosol and air and aerosol [14, 29]. Log Koa values were calculated according to the Harner and Mackay equation [30] for different environmental temperatures, recorded by some meteorological stations along the Lys Valley. Only mean summer temperatures were taken into account because, in this season, the contaminated air mass reaches high Alp sites more easily due to the higher height of the boundary layer [31]. Log Koa values, for each chlorination class, are shown in figure 4, where, three different groups (mono CB, di tri and tetra penta CB) can be easily identified. The differences in log K OA 1 suggest their different environmental fate in the Lys Valley. Heavier congeners have a strong affinity for the lipophilic compartment and volatilisation from environmental reservoirs (soils) is negligible even at low elevations; whilst the less chlorinated congeners, less strongly-bound to soils, can easily reach higher elevations. 713

18 FIGURE 3 - Altitudinal trend of PCBs fingerprints (1,400 to 2,200m data are from Blais and co-workers [8], 4,200m are from this work). ng/l 0,7 0,5 0, m a.s.l. 0,1 0,7 0,5 0,3 0,1 0,7 0,5 0,3 0,1 0,7 0,5 0,3 0,1 0,7 0,5 0,3 0,1 di tri tetra penta hexa a 1500 m a.s.l. di tri tetra penta hexa a 2000 m a.s.l. di tri tetra penta hexa a 2200 m a.s.l. di tri tetra penta hexa a 4200 m a.s.l. di tri tetra penta hexa a hepta hepta hepta hepta hepta FIGURE 4 - Log K OA values for different PCB chlorination groups at different environmental temperatures mono-cb di-cb tri-cb tetra-cb penta-cb summer mean temperature ( C) 714

19 POP concentration in the ice-core could be affected by compound losses due to revolatization [32]. This aspect is a debated question. Some authors reported no evidence of PCBs in post-depositional loss [33; 34; 35]. On the other hand, condensation temperatures, reported by Wania and Mackay [5], suggest that summer thermic conditions could promote the revolatization of lighter congeners. Log K OA figures suggest probable volatilisation for mono-cb, a doubtful situation for di and tri-cb; whilst no post-depositional loss can affect highly chlorinated PCB concentration. CONCLUSIONS The PCB concentrations found in the Lys glacier and their temporal trends are similar to those observed in remote areas where contaminant input is mainly due to long range transport. The ice core contamination fingerprint is dominated by low chlorinated congeners, which agrees with theoretical distribution models such as global distillation and the grasshopping effect. The log K OA variation in function of altitude is a useful tool for interpreting of the influence of the distillation effect on PCB glacier fingerprints. The assessment of congener-specific loads confirms that, for lighter congeners, only those that are most abundant in commercial mixtures can be found at detectable levels in this compartment. In conclusion this data supports the hypothesis that high mountains can be considered to be cold condenser. REFERENCES 1. Atlas E. and Giam C. S. (1981) Science, 211, Risebrough R.W. (1990) Beyond long range transport: a model of a global gas chromatographic system, in Long range transport of pesticides. D.A. Kurtz (ed.) Lewis Publishers, Chelsea, MI, Tanabe S., H. Hidaka and R. Tatsukawa (1983) Chemosphere, 12, Bacci E., D. Calamari, C. Gaggi, R. Fanelli, S. Focardi, M. Morosini (1986) Chemosphere 15, Wania F. and Mackay D. (1996) Environ. Sci. Technol./ News, 30, Calamari D., E. Bacci, S. Focardi, C. Gaggi, M. Morosini, M. Vighi (1991) E.S.&T. 25, McConnell L.L., J.S. Lenoir, S. Datta, J.N. Seiber, (1998) Environmental Toxicology & Chemistry, 17(12), Van de Velde K., C. Boutron, C. Ferrari, T. Bellomi, C. Barbante, S. Rudnev, M. Bolshov, (1998) Earth & Planetary Science Letters, 164 (3-4), Rosman K.J.R., C. Ly, K. Van de Velde, C.F. Boutron (2000) Earth & Planetary Science Letters, 176 (3-4), Donald D., J. Syrgiannis, R. Crosley, G. Holdsworth, D.C.G. Muir, A. Sole, D.W. Schindler (1999) E.S.&T., 33, Villa S., V. Maggi, E. Bolzacchini, B. Rindone, R. Belloli, M. Vighi (2000) Proceeding of Symposium 2000 Eurotrac-2, Garmisch-Partenkinchen 14. Bidleman T. F. (1999) Water, Air, & Soil Pollution, 115 (1-4), Datta S., L.L. Mc Connell, J.E. Baker, J. Lenoir, J.N. Seiber (1998) E.S.&T., 32, Breivik K., A. Sweetman, J.M. Pacyna, K.C. Jones Global Emission Inventory Of PCBs With Congener Resolution. A First Approach To Present The Historical Atmospheric Releases from Intentionally Produced PCBs. Setac Congress, Brighton UK, 17. Pacyna J. M (1999) Environmental cycling of selected persistent organic pollutants (POPs) in the Baltic region. Technical Report of Environmental & climate research programme (N ENV4-CT ). 18. Lavanchy V.M.H.; H.W. Gaggeler, U. Schotterer, M. Schwikowski, U. Baltensperger (1999). J Geophys Res-Atmospheres, 104, De Voogt P. and Brinkman U.A.Th. (1989) Ch. 1: Production, properties and usage of polychlorinated biphenyls. In: Kimbrough, R.D. and Jensen, A.A. (eds.), 1989: Halogenated biphenyls, terphenyls, naphtalenes, dibenzodioxins and related products. Topics in environmental health. Elesevier Science Publishers. ISBN Fiedler H Polychlorinated Biphenyls (PCBs): Uses and Environmental Releases. Proceedings of the Subregional Awareness Raising Workshop on Persistent Organic Pollutants (POPs), Cap. 6, St. Petersburg, Russian Federation, 1-4 July. 21. Bossi R., B. Larsen, G. Premazzi (1992) The Science of the Total Environment, 121, Jones K.C., G. Sanders, S.R. Wild, V. Burnett, A.E. Johnston (1992) Nature, 356, Galassi S., S. Valsecchi, G. A. Tartari (1997) Water Air Soil Poll, 99, Blais J. M., D.W. Schindler, D.C.G. Muir, L.E. Kimpe, D.B. Donald, B. Rosenberg, (1998) Nature, 395, Sanders G., K.C. Jones, J. Hamilton-Taylor, H. Dorr (1992). E.S.&T., 26, Alcock R. E., A. E. Johnston, S. P. Mc Grath, M.L. Berrow, K.C.Jones (1993) E.S. T, 27,

20 25. Van Metre P. C., E. Callender, C.C. Fulles (1997) E.S.&T., 31, Schulz, D.E., G. Petrick, J.C. Duinker (1989) E.S.&T, 23 (7), Frame G. M., R.E. Wagner, J.C. Carnahan, J.F. Jr Brown, R.J. May, L.A. Smullen, D.L. Bedard (1996) Chemosphere, 33, Gregor D.J., A.J. Peters, C. Texeira, N. Jones, C. Spencer (1995) The Science of the Total Environment, 160/161, Finizio A., D. Mackay, T.F. Bidleman, T. Harner (1997) Atmospheric Environment, 31 (15), Harner T. and Mackay D. (1995) E S &T., 29, Lugauer M., U. Baltenspeger, M. Furger, H.W. Gaggler, D.T. Jost, M. Schwikowski, H. Wanner (1998) Tellus Series B-Chemical & Physical Meteorology, 50, Gregor D.J Deposition and accumulation of selected agricultural pesticides in Canadian artic snow. In: Long range transport of pesticides (D.A. Kurtz ed.) Lewis Publisher: Franz T.P and Eisenreich S.J. (1998) E.S.&T., 32, Oehme M., J.E. Haugen, M. Schlabach (1996) E.S.&T., 30, Macdonald, R.W., L.A. Barrie, T.F. Bidleman, M.L. Diamond, D.J. Gregor, R.G. Semkin, W.M.J. Strachan, Y.F. Li, F. Wania, M. Alaee, L.B. Alexeeva, S.M. Backus, R. Bailey, J.M. Bewers, C. Gobeil, C.J. Halsall, T. Harner, J.T. Hoff, L.M.M. Jantunen, W.L. Lockhart, D. Mackay, D.C.G. Muir, J. Pudykiewicz, K.J. Reimer, J.N. Smith, G.A. Stern, W.H. Schroeder, R. Wagemann, M.B. Yunker, (2000) The Science of the Total Environment, 254 (2-3), Received for publication: July 20, 2001 Accepted for publication: September 15, 2001 CORRESPONDING AUTHOR Villa Sara Dept. of Environmental and Landscape Science University of Milano Bicocca Piazza della Scienza Milano - ITALY Phone: Fax: sara.villa@unimib.it FEB/ Vol.10/ No.9/2001 pages