Metals, Metalloids and Radionuclides in the Baltic Sea Ecosystem docx

Trace Metals in the Environment 5 Metals, Metalloids and Radionuclides in the Baltic Sea Ecosystem... Among the key factors influencing this distribution are: distance from the transitio

Trace Metals in the Environment 5

Metals, Metalloids and Radionuclides in the Baltic Sea Ecosystem

Series Editor." Jerome O Nriagu

Department of Environmental and Industrial Health School of Public Health

University of Michigan Ann Arbor, Michigan 48109-2029 USA

Other volumes in this series."

Trace Metals in the Environment 5

Metals, Metalloids

and Radionuclides in

the Baltic Sea Ecosystem

Piotr Szefer

Department of Food Sciences

Medical University of Gdahsk

80-416 Gdahsk, Poland

2 0 0 2

E L S E V I E R

A m s t e r d a m 9 L o n d o n 9 N e w Y o r k O x f o r d 9 P a r i s 9 S h a n n o n " T o k y o

Sara Burgerhartstraat 25

P.O Box 211, 1000 AE Amsterdam, The Netherlands

9 2002 Elsevier Science B.V All rights reserved

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To memory of my Parents

vii

Acknowledgements

I particularly wish to express my special appreciation to Professor Jerome Nriagu, the Editor of the Science of the Total Environment, for encouraging me to write this book I would like to thank Mrs Mary Malin and Mr Peter Henn, the Senior Publishing Editors, Mrs Conny Kreinz, the Production Editor, as well as

Mr Simon Richert from Elsevier, for their co-operation, understanding and great patience I particularly wish to thank Elsevier for their willingness to add extra material, even at a late date, to ensure that the book is up to date I am also very grateful to Dr Eric I Hamilton, the Editor-in-Chief of the Science of the Total Environment, for his critical and constructive remarks concerning all my manuscripts published in the journal; scientific content of these papers constitutes important part of the book

My most sincere thanks are extended to Dr Geoffrey E Glasby, Marine and Environmental Consultant from Sheffield, for many stimulating discussions during his visits to my laboratory I am also especially indebted to Professor Philip

S Rainbow from the Natural History Museum in London for much helpful dis- cussion which undoubtedly contributed to improvement of the book quality My wife Krystyna and daughter Magdalena are heartily thanked for their patience and support I would like to thank Dr A Lataia and Dr J Warzocha for their help in the collection of literature data concerning geographical distribution of phyto- and zoobenthos in the marine environments

I am grateful to various publishers and authors for permission to use figures, tables and photographs from previously published papers which are their copyright Many thanks to Urszula Wawrzyfiska and Maksymilian Biniakiewicz from Prin- ting-house of the Foundation for the Development of Gdafisk University who have contributed to the text typesetting of the manuscript

Gdatisk

Spring 2001

Piotr Szefer

Preface

"The external world has proved

to be surprisingly obedient to logic"

Bertrand Russel

The Baltic Sea is a unique basin, being productive with intensive fishing po- tential and has therefore been the object of many studies It is a brackish, non- tidal, relatively shallow and semi-enclosed sea The Baltic is located at a high lati- tude, hence one of its characteristic features is ice Another unique geographical pattern are the archipelagos located off the coast of Stockholm which consist of more than 25 000 islands The relative ionic concentration of toxic substances e.g chemical elements is generally higher in the low-saline Baltic Sea than compared

to the North Sea The drainage area is densely populated, heavily industrialised and is characterized by intensive agriculture Therefore this sea is thought to be extremely polluted and, with a wide range of contributing factors to its level of pollution, there are obvious implications for the people, flora and fauna in the surrounding Baltic states

Although the Baltic Sea is divided into natural basins by bottom topography and into economic sectors by man it represents an integrated system, highly sensi- tive to what happens in its contact zones with the adjacent North Sea, the land and the atmosphere Areas suffering from pollution are unevenly distributed within the sea Among the key factors influencing this distribution are: distance from the transition zone between the North Sea and the Baltic Sea; local hydro- logic and hydrographic conditions; the catchment area of the adjacent rivers and the extent of conservation measures in the adjacent areas At the end of the 1960s great attention was paid to the marked deterioration of water and biota in the Baltic Sea, resulting in the preparation and signing of the Convention on the Protection of the Marine Environment of the Baltic Sea Area (i.e the Helsinki

Convention) by all riparian countries Considering the geopolitical situation in this region, the Helsinki Convention of 1974 should be regarded as a unique in- ternational agreement, covering all sources of pollution of the open sea areas of the Baltic However, until 1992 the coastal zones were not included in the Hel- sinki Convention

Since the beginning of the 1980's, a series of assessments covering the wide range of ecological problems has been published by the Helsinki Commission (HELCOM) These assessments, prepared by numerous expert groups, summarise scientific results from the beginning of the century and reflect the present status

of knowledge resulting from the research and monitoring programmes The achievements of these collective studies are utilised in this book as valuable back- ground information and are cited under the name HELCOM Also since the 1980's, our knowledge of the biogeochemistry of the Baltic Sea has improved re- markably with results being published at first mostly in national journals and later also in international journals with a biogeochemical and environmental pollution orientation This book has partly synthesised the wide-ranging research done, and

it is envisaged that it will prove to be a valuable addition to the literature The book discusses the distribution and cycling of metals, metalloids and radionuclides in the Baltic Sea and, where needed, in adjacent northern or other seas The main aim of the book is to acquaint the reader with the distribution, bioavailability, fate and sources of chemical pollutants in the Baltic environment (seawater, suspended matter, bottom sediments, ferromanganese concretions, sea- weed, plankton, molluscs, crustaceans, nereids, fish, waterfowls, marine mam- mals) The distribution of pollutants in the atmosphere (aerosol, wet and dry fall-out) as well as in the rivers of the Baltic catchment have also been consid- ered Justification for such an approach is that the atmosphere and most seas do not have borders, even in the case of such a basin as the semi-enclosed Baltic Sea which is connected with the North Sea via the Danish Straits Therefore chemical elements and radionuclides are often transported long distances from their emis- sion sources via atmospheric circulation, sea currents and rivers Since the marine cycle of bioelements such as C, N, P and Si is often strictly related to the fate of metals and metalloids, some aspects concerning these nutrients have also been in- cluded in the book

Because some organisms e.g marine mammals, waterfowls and fish can be ef- fective carriers of pollutants from even remote areas, concentration data for Bal- tic migrants were compared together (where needed) with those corresponding to non temperate zones e.g sub-Arctic waters of the Northern Hemisphere In the case of sedentary organisms, such as phyto- and zoobenthos, worldwide data were cited in the book because of the universal biomonitoring significance and utilisa- tion of the sedentary bottom animals (e.g Mytilidae) having a similar affinity to most trace elements irrespective of their geographical habitation Knowledge of the chemical composition of Baltic benthal organisms and those from other geo- graphical areas allows us to estimate the pollution status of compared marine en-

PREFACE xi

vironments, although it should be borne in mind that some environmental pa- rameters e.g salinity can influence bioaccumulation of several trace elements in biota

In order to set the data in context, characteristics of the main features of both the abiotic (general characteristics, distribution, hydrological and geochemical features), and biotic (taxonomy- classification to particular categories, habitat, food habits) compartments of the Baltic Sea are presented Particular compo- nents of the Baltic ecosystem are considered as potential monitors of pollutants Budgets of chemical elements and the ecological status of the Baltic Sea in the past, present and future are presented Estimates of health risks to man in re- spect to some toxic metals and radionuclides in fish and seafood are briefly dis- cussed The book is mainly directed to marine chemists, geochemists, environ- mentalists, biologists, ecologists, ecotoxicologists, educators in marine sciences as well as to students of oceanography Although the Baltic Sea has been widely studied it is hoped that the book makes possible the identification of gaps in our environmental knowledge with certain sections establishing possible priorities, key areas or strategies for future research

Piotr Szefer

Gdafisk, Poland Spring 2001

xiii

Contents

Acknowledgements vii

Preface ix

C h a p t e r 1 I n t r o d u c t i o n 1

C h a p t e r 2 Air a n d W a t e r as a M e d i u m for Chemical Elements 43

C h a p t e r 3 Biota as a M e d i u m for Chemical Elements 181

C h a p t e r 4 Deposits as a M e d i u m for Chemical Elements 467

C h a p t e r 5 Bioavailability a n d Biomagnification of Chemical Elements a n d Radionuclides 565

C h a p t e r 6 Sources of Chemical Elements 603

C h a p t e r 7 M o n i t o r s of Baltic Sea Pollution 649

C h a p t e r 8 E s t i m a t e of H e a l t h Risk 687

C h a p t e r 9 Global I n p u t of Chemical Elements a n d Pollution Status of the Baltic Sea 697

A u t h o r Index 711

Species Index 735

Subject Index 739

Chapter 1 Introduction

A CHARACTERISTICS OF THE BALTIC SEA BASIN

Regional setting

The general characteristics (meteorology and chemical oceanography; fishes and fisheries, pollution, geology, international management and co-operation) of the Baltic Sea including environmental state of its particular subareas have been well and detailed described in a number of major text books, monographs, re- ports and articles (see for example: Manheim, 1961; Hartmann, 1964; Fonselius, 1969; Magaard and Rheinheimer, 1974; Lomniewski et al., 1975; Gudelis and Emelyanov, 1976; Millero, 1978; Dybern and Fonselius, 1981; Ehlin, 1981; Blazhchishin and Lukashev, 1981; Grasshoff and Voipio, 1981; H~illfors et al., 1981; Kullenberg, 1981; Lisitzyn and Emelyanov, 1981; Ojaveer et al., 1981; Sj6- blom and Voipio, 1981; Winterhalter et al., 1981; Blazhchishin, 1982a, 1982b, 1982c; Emelyanov and Pustelnikov, 1982; Elmgren, 1984; Fonselius et al., 1984; Falkenmark, 1986; HELCOM, 1986, 1998a; Augustowski, 1987; Franck et al., 1987; Ambio, 1990a, 1990b; Anon, 1990; Gran61i et al., 1990; Mikulski, 1991; Emeis et al., 1992; Matthfius, 1992, 1993a, 1993b; Matth~ius and Francke, 1992; Winterhalter, 1992; Bergstr6m and Carlson, 1993; H~gerhfill, 1994; Majewski and Lauer, 1994; Emelyanov, 1995; Harff et al., 1995; HELCOM, 1996; Huckriede et al., 1996; Trzosifiska and Lysiak-Pastuszak, 1996; Gingele and Leipe, 1997; Jensen

et al., 1997, 1999; Lemke et al., 1997, 1998; Rheinheimer, 1998; Jansson and Dahlberg, 1999; Lysiak-Pastuszak, 1999; Sokolov and Wulff, 1999; Falandysz et al., 2000; Kautsky and Kautsky, 2000; Blomqvist and Heiskanen, 2001; Lemke et al., 2001) and therefore it is not the intention to repeat this published information

Rather attention will be directed forward the presentation of these basic environ- mental problems shortly which are linked with the fate of selected chemical ele- ments in the Baltic Sea

The Baltic Sea is a young postglacial inland sea, with its drainage basin over four times its sea area (Fig 1.1) The drainage b a s i n - densely inhabited and ur- banised is used mainly for agricultural and industrial purposes (Falandysz et al., 2000) The Baltic Sea is connected to the North Sea (Atlantic Ocean) via the

A CHARACTERISTICS OF THE BALTIC SEA BASIN

Kattegat and narrow inlets of the Belt Sea and Sound - the transition zone The Baltic Proper is the largest subdivision of the Baltic Sea It has a surface area of

211 069 km 2 (51% of the whole sea) and the volume of 13 045 km 3 (60 % of the to- tal) (Melvasalo et al., 1981; HELCOM, 1990, 1996) It covers the area between the Darss Sill (18 m depth) in the transition zone and the Gulfs of Bothnia, Finland and Riga Several regions are distinguished based on the bottom topography: the Arkona Basin, the Bornholm Basin and the Gotland Basin (Fig 1.2) The Gotland Basin in subdivided into its eastern and western parts The Gdafisk Basin is

a southward extension of the Eastern Gotland Basin; it is frequently treated as

a separate natural region because the Gdafisk Deep (max depth 118 m) acts as

a sink for the suspended matter carried by the Vistula River, which is the largest river draining the Baltic Proper (Falandysz et al., 2000)

Continuous inflow of more saline water from the North Sea into the Baltic Sea is hampered by shallow sills Only major inflows, approximately 100 km 3 in volume, reach the Bornholm Basin To renew the deep or intermediate water lay-

ers in the Gotland and Gdafisk Basins, even greater volumes of dense oceanic water of high salinity, low temperature and high oxygen concentration are re- quired These proceed in cascades eastward and northward through the Sfupsk Furrow which has a sill depth of approximately 60 m Major inflows occur at ir- regular intervals, mostly in winter Their impact depends not only on the volume but also on its salinity and the duration of the event The causes of these inflow- ing water are not well understood but meteorological and hydrological conditions play a great role (Falandysz et al., 2000)

Due to an extensive river run-off, there are pronounced horizontal salinity gradients in the surface layers of the Baltic Sea (Fig 1.3) Moreover, rivers flow- ing into the Baltic Sea carry various types of pollutants that could negatively af- fect the ecological balance of the sea (Falkenmark, 1986) The salinity of surface water is highly variable within each region In the Baltic Proper, it ranges from about 1 psu in estuarine areas up to 9 psu in the western region (HELCOM, 1986)

Cyberski (1995) reported statistically significant long-term trends in the sea- sonal outflows of the rivers draining into the Baltic whereas the mean annual flow rates of most rivers displayed only some fluctuations with time These sea- sonal changes began in the 1920s and have accelerated since the 1970s They co- incide with the energy crisis and the resulting attempts to improve water storage facilities for electricity generating stations Seasonal variations in the river outflow

to the Baltic Sea as well as recent climatic changes may also affect different ele-

.e/

@5.0 km 3 psu /f

A CHARACFERISTICS OF T H E BALTIC SEA BASIN

ments in the water balance As an example, they may influence the salinity, one

of the fundamental factors controlling environmental conditions and the distribu- tion of biological species within the Baltic Sea (Falandysz et al., 2000)

A horizontal salinity gradient also exists in the deep waters of the Baltic Proper Fonselius et al (1984) studied 100-year series of salinity data They found that salinity varied from over 14 psu to about 21 psu in the near-bottom layer of the Bornholm Deep, whereas in the southern and northern basins these variations were less, e.g from over 11 to 14 psu in the Gotland Deep

Changes in the surface water temperature in the Baltic Sea are governed by the increased continental influence in the east and the considerable north-south extent of the Baltic Sea (Melvasalo et al., 1981) In the Baltic Proper, the average winter sea surface temperatures are around 2~ The extent of ice cover is very variable, depending on the severity of winter and the region (Majewski and Lauer, 1994) The mean sea surface temperature is 16-18~ in the southern part, about 16~ in the central part and 15-16~ in the northern part of the Baltic Proper during August During 1989-1993, the mild winters caused positive water temperature anomalies (HELCOM, 1996) The deep waters have more or less stable temperatures (5-8~ which are influenced by the frequency and season of the major inflows

The relationships between separate elements of water budget and seasonal variations in water temperature result in marked vertical gradients in water den- sity of the Baltic Sea In summer, warm surface water is separated from the cold winter water by the thermocline at a water depth of approximately 20 m The main barrier between the low salinity upper (isohaline) layers and higher salinity (heterohaline) deep layers occurs at 40-70 m, on the average, depending on the region and the period under consideration Major inflows of water from the North Sea significantly change the location of the permanent halocline within the water column and the relative volumes of the isohaline and heterohaline layers (Falandysz et al., 2000)

The residence time of Baltic Sea water, estimated from the salinity distribu- tion, to be in the range of 20-35 years, varies spatially Those elements which take part in the biogeochemical processes spend much shorter time in the Baltic Wulff et al (1990) calculated that the average residence times for silicate, phos- phorus and nitrogen compounds are 13, 11 and 5 years, respectively

Flora and fauna in the Baltic Sea

The main natural factor determining the occurrence of species in the Baltic is low salinity, which limits the occurrence of many marine species as well as fresh water species resulting in a relatively low biodiversity (Falandysz et al., 2000) Most of the typically marine species (e.g Echinodermata, Porifera, Anthozoa) do not occur in this region or occur on the edge of their distribution range, therefore even small changes in environmental conditions may influence their spatial distri- bution A decreasing number of marine species along with diminishing salinity

(due to increasing distance from the Danish Straits) is a characteristic feature of the Baltic Sea The least number of species occur in waters with salinity ranging from 5 to 8 psu, that is, salinity of the northern part of the Baltic Baltic Proper is thus a region intermediary between Kattegat and transition zone, reach in marine species, and Bothnian Sea, where only a few marine species occur The low tem- perature is also important factor limiting immigration of marine organisms into the Baltic (Dahl, 1956; Segerstr~le, 1957, 1972; Remane, 1958) In addition, the relatively young age of the Baltic having been a brackish sea for only 6000 years, should be taken into account There are therefore not many species which can

be regarded as typical Baltic, brackish-water species Most species have immi- grated to the Baltic Sea from near-by seas and freshwater bodies during different periods up its evolution, beginning with the last glacial period (about 12,000 years ago) There are four groups of natural immigrants in the Baltic flora and fauna The first group consists of Northwest European euryhaline marine and brackish- water species, e.g M a c o m a b a l t h i c a - Bivalvia and C l u p e a h a r e n g u s - Pisces, and the second are freshwater species, e.g T h e o d o x u s f l u v i a t i l i s - Gastropoda and

P e r c a f l u v i a t i l i s - Pisces (Falandysz et al., 2000) The third and fourth groups in- clude glacial relikts which reached the Baltic either through ice-dammed lakes from the Syberia, e.g S a d u r i a e n t o m o n - Isopoda, M y s i s relicta - Mysidaecea, or

by a westerly route through the sea, e.g A s t a r t e borealis - Bivalvia, P o n t o p o r e i a

f e m o r a t a - Amphipoda This migration process still continues (Dahl 1956; Seger- str~ile 1957; Jansson, 1972; Magaard and Rheinheimer, 1974; Elmgren, 1984; Lo- zan et al., 1996)

The main coastal and marine biotopes

Sandy coasts (moraine landscape formed by glacial and postglacial processes) dominate the shores of Germany, Poland, Lithuania, Russia, Latvia as well as southern Sweden Sandy coasts often have an accumulative-abrasive character; sandy beaches and dunes in various stages of succession (from white, green, grey dunes to brown dunes covered by forests - e.g Leba in Poland) are typical ele- ments of such coasts High active cliffs, so-called moraine cliffs built of clays and sands are also present In the western part (e.g Rtigen Island) cliff and rocky coasts (bedrock on Bornholm) are found (Falandysz et al., 2000)

In the southern part of the Baltic Proper the characteristic elements are la- goons: Szczecin Lagoon (Oder Haft), Vistula Lagoon and Curonian Lagoon The coastal lakes are also typical elements of the southern coasts

They are a few types of coastal salty meadows as well as coastal bogs which are a typical element of the coastal marshes These are pit bogs of two types -

"high" fed by rain waters and "low"- fed by ground and surface waters Large pit bog complexes are located along the southern coasts (e.g along Lebsko Lake in Poland) "Low" pit bogs do not form large complexes, but are dispersed as small patches along the entire coast in meadow and pasture complexes

The pelagic coastal biotopes are found within depths down to 15-25 rn where interactions between waves and the see floor usually occur Pelagic offshore bio-

A CHARACTERISTICS OF THE BALTIC SEA BASIN

topes are the water body of the open Baltic Sea area deeper than 15-25 m usu- ally without interaction between wave orbits and the sea floor The offshore bio- topes can be divided into water body above and below the halocline (Falandysz et al., 2000)

The sea floor of the coastal zone is dominated by sandy sediments mixed with gravel deposits In the deep water zone, silty sediments prevail (Loz~n et al., 1996; HELCOM, 1998a)

Eutrophication

Seasonal and annual variations in the concentrations of nutrients in the Baltic Sea have been widely studied and extensively described in the scientific literature Because of the differences in climate and bathymetry within the Baltic Sea, they are usually referred to particular regions and/or water bodies (Melvasalo et al., 1981; HELCOM, 1987, 1990, 1993, 1996)

Seasonal fluctuations in the nutrient concentrations in surface waters of the Bornholm and Gdafisk Deeps and the southern part of the Gotland Basin, aver- aged over 20 years, show distinct temporal and spatial differences in the accumu- lation pattern during the winter as well as the uptake by autotrophic organisms during spring There is a time-lag of about 2-4 weeks in the accumulation and as- similation peaks, when moving from the Arkona Basin toward the northern Bal- tic Another time-lag, of about 1-2 weeks, occurs between the coastal zone and the off-shore areas (Falandysz et al., 2000)

In the 1990s, the winter nutrient concentrations in the photic layer become much more equal throughout the off-shore area of the Baltic Proper However, exceptions were found in the northern Baltic (the Landsort Deep with much ele- vated phosphate and nitrate content), as well as in the southern Baltic (the Gdafisk Deep with much elevated nitrate content) Comparing with the 1960s, an overall concentration increase took place: 1.5-5 times for nitrate and 2-3.5 times for phosphate, depending on the region During the vernal phytoplankton blooms the pool of assimilable nitrogen and phosphorus compounds was already con- sumed by June-July in all areas except the estuaries Nitrate depletion in warm water creates conditions promoting the growth of blue-green algae, which are able to make use of N 2 and add several hundred thousand tons of nitrogen to the waters of the Baltic Proper From summer until December nitrogen is a limiting nutrient in the Baltic ecosystem, and the nitrogen content appears to be almost balanced in most regions, with respect to input versus uptake However, some ex- ceptions were recognised, viz the Pomeranian Bay and the most inner part of the Gulf of Gdafisk, where phosphorus has becomes a temporary limiting nutrient

at the beginning of summer since the 1980s (Trzosifiska, 1992; Falandysz et al., 2000)

In contrast to nitrate and phosphate, silicate has never been the limiting factor for productivity of the Baltic Proper However, since the 1980s, almost complete silicate consumption has occasionally occurred following vast phytoplankton

blooms In spite of some decline found in the 1990s in the silicate uptake, ampli- tudes in silicate concentrations were high, 5-7 mmol m -3 annually Seasonal fluctua- tions of silicate display evident changes as a consequence of the autumnal species development Such fluctuations were previously observed for the phosphate and nitrate, as well Recently they flattened in the southern Baltic, where extremely low concentrations of nitrate and phosphate and the supersaturation of surface water with oxygen cover the whole summer and autumn, until December This situation can be partly attributed to mild winters and variations in the riverine run-off The accumulation of nutrients starts in January-February At the peak of nutrient concentration during winter, the mean molar ratio of nitrate to phos- phate is approximately 7 in the Bornholm Deep and the Gotland Basin, but as high as 10 in the Gdafisk Deep When compared with the 1960s, this means an increase in the N/P ratio by few percent for the off-shore regions, and by 50 % for the Gdafisk Basin (Falandysz et al., 2000)

Before the eutrophication accelerated in the 1970s, the N/P ratios in the tro- phic zone of the Baltic Proper were significantly lower than the Redfield ratio (16:1), which reflected the steady state relations between the environment and the biota in the ocean Even so, nitrate and phosphate have been taken up in proportions approximating the Redfield ratio HELCOM (1987) investigated the uptake of nitrogen and phosphorus during the vernal phytoplankton bloom in the Bornholm Basin and found the relation to be about 15:1 A somewhat lower mean value (14:1) was found for the spring/summer species in the southern Bal- tic, including the off-shore and coastal areas (HELCOM 1996) Interregional def- ferences were, however, considerable The mean uptake ratio of silicate versus phosphate was close to the Redfield ratio; it ranged from 13:1 in the Gotland Ba- sin to 18:1 in the Bornholm Deep

Variations observed in saturation with oxygen in the near-bottom water layer reflect a seasonality in the oxygen utilized in respiration and remineralisation pro- cesses, though they are to a certain extend overwhelmed by the hydrographic oc- currences, such as occasional oceanic inflows, relatively slow water advection, ver- tical density gradient weakening northwards and the long stagnation period Sub- stantial fluctuations in the phosphate concentrations are connected with their re- suspention or remobilization from the bottom sediments in accordance with alter- nating oxygen conditions Silicate also accumulates in the deep waters whenever dissolved oxygen concentrations decline On the other hand, decreasing redox po- tential promotes the denitrification activity It has been calculated that denitrifica- tion is responsible for the overall nitrogen loss of 470000 tons annually (HELCOM, 1990)

A variety of the input and sink mechanisms, as well as temporal and spatial differences in their efficiency, do not permit any realistic mass balance calcula- tions Nevertheless, nutrient budgets calculated by Wulff and Stigebrandt (Ambio, 1990) for phosphorus, nitrogen and silicate in particular parts of the Baltic Sea in 1971-1981 are very impressive and contain some management implications re- garding the desired reduction in the pollution loads

A CHARACTERISTICS OF THE BALTIC SEA BASIN

The first signs of the increasing fertility were reported in the mid-1970s (Mel- vasalo et al., 1981, HELCOM, 1987) The long-term trends, calculated by means

of approximately 20 year data series, were in most cases highly significant and positive from the statistical point of view In surface water of the Baltic Proper, the mean annual accumulation rates of phosphate during the winter seasons ranged from 0.015 to 0.26 mmol m -3 and of nitrate from 0.17 do 0.34 mmol m -3, depending on the region Even a higher rate, exceeding 2-4 times that of the sur- face water, was found for phosphate in the deep water layers In spite of anoxic conditions, nitrate accumulated in some water layers of the Baltic deep basins (Nehring, 1989)

In the 1980s, when loads from external sources were still high, the rate of eutrophication slowed down The most characteristic feature of that period was the long-lasting stagnation in the Baltic deep waters, the longest ever been ob- served during the Twentieth century As a result of the diminishing salinity and increasing temperature of the deep waters, the weakening vertical density gradi- ent supported downward transport of oxygen and upward transport of nutrients over a vast area of bottom at the intermediate water depths (HELCOM, 1990) The long-term increase in the phosphate and nitrate concentrations continued, but was, interrupted by periods with decreasing concentrations It has been found almost cyclic behaviour in the phosphate and nitrate accumulation in the Gdafisk Deep of 3 and 6-7 years (HELCOM, 1990) This was probably caused by varia- tions in the atmospheric circulation affecting both the riverine run-off and the oceanic inflows

At present, the concentrations of assimilable compounds of phosphorus, nitro- gen and silicates in the photic zone of the Baltic Proper are at a stable level, though sufficiently high to support intensive primary production During the last few decades the phytoplankton primary production has almost doubled in some areas, with a resultant doubling of phytoplankton biomass and its subsequent sedimentation (Ambio, 1990)

Biological effects of eutrophication

Eutrophication is considered to be the main anthropogenic factor influencing life in the Baltic The most important effects of eutrophication are such as in- creasing primary production, decrease in water transparency and increased or- ganic matter sedimentation resulting in oxygen depletion occurrence There is not much evidence of primary production increase, mainly due to large natural an- nual phytoplankton variability, relatively infrequent sampling, influence of local factors and, finally, changes in measurement techniques However, intensity of phytoplankton blooms may be a general indicator of primary production increase More frequent blooms of toxic algae may also be related to eutrophication In the Baltic Proper, no major negative effects related to harmful algae have been ob- served during phytoplankton blooms, although blue green algae, toxic to mam-

cystis aeruginosa, Aphanizomenon flos-aquae, and also Dinophysis acuminata,

trends in the abundance and biomass of zooplankton, mainly due to lack of long- term measurements and to changes in sampling methodology Distinctive, often drastic, changes, which might be an indirect indication of the influence of euthro- phication on Baltic marine life, were observed in benthic macroalgae and vascular plant composition and distribution, during the 1970s A decrease in water trans- parency may explain the decrease in depth range of bottom plants Such changes were observed along the coasts of Latvia, Lithuania, Russia, Poland, Germany and the southern coast of Sweden Fucus vesiculosus communities underwent the most drastic changes, and the community has vanished in some regions In the shallow littoral zone, many species of red and brown algae have become extinct, e.g Fucus vesiculosus, Furcellaria lumbricalis Others, e.g vascular plants such as sea grass - Zostera marina occur within more limited areas In their place, oppor- tunistic green algae (Enteromorpha intestinalis, Cladophora sp.) and filamentous red algae from the Ectocarpaceae genus (Ectocarpus and PilayeUa) have become dominant (Falandysz et al., 2000)

Long-living bottom fauna also reflect the adverse effects of excessive nutrient discharges to the marine environment Bottom organisms depend on food of pe- lagic origin Increased sedimentation results in both positive and negative changes

in benthos Positive effects include an increase in biomass and abundance of mac- rozoobenthos observed in some regions above the halocline Negative effects in- clude a decrease in species diversity through elimination of species less resistant

to environmental changes and a concomitant increase in opportunistic species The most drastic, adverse changes are noted below the halocline Long-term oxy- gen deficits, resulting from increased sedimentation, caused changes in species composition, domination structure, including, in some cases, even the total disap- pearance of the macroscopic life on the bottom In the first half of the twentieth century, Bornholm, Gdansk and Gotland Basins were inhabited by numerous bot- tom fauna species The total extinction of macrozoobenthos on the Bornholm Ba- sin bottom was observed for the first time in the early 1950 Presently, the bottom

of deeps below 70-80 rn depth, shows no signs of macroscopic life, and sediments are covered by anaerobic bacteria There is a lot to suggest that oxygen deficiency

in the deep water has contributed to low effectiveness of cod spawning Cod may hatch only in waters of 10-11 psu minimum salinity, which allows spawn to float

in pelagic zone In less saline waters the cod eggs fall down to the bottom and die In the Bornholm Basin, where waters are sufficiently saline for effective spawning, oxygen deficits occurring lately as a result of lack of inflows and eutrophication, became a limiting factor in deep water zone (< 70 m) Also, ob- served recently, decrease in salinity causing halocline uplift, which in turn, widens the water layer not influenced by convection mixing, diminishes effectiveness of cod spawning In the shallow littoral zone, increasing sedimentation of organic matter together with a lack of water mixing contribute to summer oxygen deft-

A CHARACI~RISTICS OF THE BALTIC SEA BASIN 11 ciencies, which in turn adversaly influence primarily bottom perennial species (e.g Pomeranian Bay, Gulf of Gdafisk) (Magaard and Rheinheimer, 1974; Jans- son, 1972; Jarvekulg, 1979; Kautsky et al., 1986; Cederwall and Elmgren, 1990; Andell et al., 1994; Loz~in et al., 1996; HELCOM, 1996, 1998a)

Industrial production in the drainage area

Several authors (Bruneau, 1980; Elmgren, 1989; Lithner et al., 1990; Backlund

et al, 1992; Jonsson et al., 1996; Rheinheimer, 1998; Jansson and Dahlberg, 1999) reported on man's impact on the Baltic ecosystem as well as the past and recent pollution sources in its drainage area Riverine and direct loads of pollutants (heavy metals and nutrients) into the Baltic Sea are an important environmental problem (HELCOM, 1993, 1998a) Therefore, the monitoring survey of trace ele- ments and radionuclides is necessary to control the anthropogenic input of pollut- ants and contaminants to the Baltic Sea (HELCOM, 1991, 1993, 1997a, 1997b, 1998a, 1998b) The industries in the Baltic countries are largely based on locally available row materials, e.g the deposits of Fe, Cu, Pb and Zn ores which sup- port numerous steel mills and stainless steel works, copper and zinc smelters and aluminium refineries Some major industrial regions located along the coasts of the Baltic Sea are presented in Fig 1.4 This is reported that riverine heavy met- als load is the largest source of total pollution load amounting to ca 90% The municipal and industrial wastewater discharges as well as diffuse discharges are probably the predominant anthropogenic sources in the riverine load (HELCOM, 1998a) According to Lithner et al (1990) the anthropogenic loads of Cd, Pb and

Hg to the Baltic Proper were from 5 to 7 times higher than the background loads This pollutant input has been reflected by increasing concentrations of Cd, Cu and Zn in fish during 1980s However, Pb showed a decreasing temporal trends possibly owing to the significantly reduced air emissions from car traffic in Fin- land, Sweden, Denmark and Germany (HELCOM, 1996; Jansson and Dahlberg, 1999) The Bothnian Bay catchment area comprises 260,675 km 2 of which 56% belongs to Finland, 44% to Sweden and < 1% to Norway (HELCOM, 1998a) According to Bruneau (1980) both Finland and Sweden have had steel mills on the Bothnian Bay Finnish stainless steel plants possibly have discharged Ni and

Cr from the pickling operations The Finnish fertiliser plant located the most northern in the drainage area and Swedish forest industries- on the coast as well

as pulp mills in this regions are suspected to be emitters of pollutants to the Bothnian Sea (Bruneau, 1980) The Bothnian Sea catchment area comprises 220,765 km 2, of which 80% belongs to Sweden, 18% to Finland and 2% to Nor- way (HELCOM, 1998a) Finland has copper smelters, Sweden- aluminium plant;

a still mill and several stainless steel plants are located in the area The chemical industry is predominantly located in Finland, i.e refinery, fertiliser and chlorine plants and in S w e d e n - chlorine and PCV plants It is important to note that chlorine plants are based on the mercury method but discharge of this element is very low owing to extensive measures to its reduce Recently a non-mercury type

Energy (Power plants)

Nuclear power plants

:~.~7!~ ' !i i: " ~ , , ', " '

A CHARACTERISTICS OF T H E BALTIC SEA BASIN 13 Gulf of Finland comprises 412,900 km 2, of which 67% belongs to Russia, 26% to Finland, 7% to Estonia and < 0.1% to Latvia (HELCOM, 1998a) In the Russia are located aluminium works and fertilise industry; the latter is also located on the Estonian coast The Russia has also a highly developed chemical industry, petrochemical plants and the pulp and paper industry Most of pollutants are transported through the Neva River to the Gulf of Finland, and thus affect the Baltic Sea Scandinavian petrochemical installation is located on the Baltic coast; the Finnish steel mills, pulp and paper industry and manufacturing industry are located

in this area and on the lakes and streams where pollutants are discharged either directly or through Lake Ladoga (Bruneau, 1980) The catchment area of the Gulf of Riga comprises 128,340 km 2, of which 39% belongs to Latvia, 20% to Be- larus, 18% to Russia, 14% to Estonia and 9% to Lithuania (HELCOM, 1998a) According to Bruneau (1980) the drainage area of the Gulf of Riga seems to be rather poorly industrialised In this region, however, were situated a very large re- finery, petrochemical plant and some paper mills, mostly of small size The catch- ment area of the Baltic Proper comprises 574,245 km 2, to which all Contracting Parties except Finland belong as well as Non-Contracting Parties of Belarus, the Czech Republic, Ukraine and Slovakia with the total area of 78,360 km 2 The catchment area of the Contracting Parties is divided into particular subareas as follows: 54% to Poland, 15% to Sweden, 9% to Lithuania, 3% to Russia, 2.6% to Germany, 2% to Latvia, 0.2% to Denmark and 0.2% to Estonia The Polish riv- ers, the Vistula and Oder, enter the Baltic Proper transporting all pollutants even from industry located in such remote southern area as borders of the Czech Re- public and Slovakia (HELCOM, 1998a) Poland is much industrialised country with most of the smelters and steel mills located in the south In Poland is also produced copper, zinc and aluminium There are also refineries, petrochemical centre, fertiliser production, mines, textile industry and pulp and paper mills On the Swedish side, pollutants entering the Baltic Sea from Lake Mfilaren originate partly from the central industrial district located in the vicinity of numerous old mines There are also ammonia plants, fertiliser plants, small steel mills and stainless steel mills including the Oxel6sund steel mill on the coast Among other industries on the Swedish coast and on rivers discharging to the Baltic Proper are mostly pulp and paper mills In the Russia fertilisers plants are located on the southeast side of the Baltic while in Germany the most important sources of pol- lutants are petrochemical plant and steel mills However, most industrial pollut- ants are transported via rivers into the North Sea (Bruneau, 1980) The collective deposition of trace elements such as Zn, Cu, Cd, Pb, As, Hg, Cr and Ni to the Baltic Sea, i.e to the Baltic Proper, Gulf of Finland and Gulf of Riga has been estimated (Lithner et al., 1990) The Chernobyl-derived 13VCs has been evaluated

as significant (65 TBq) for all Finnish rivers discharging into the Baltic Sea during 1986-1996 as well as for five Russian rivers (14 TBq) discharging from the former USSR during only 1986-1988 and for Polish Vistula River (18 TBq) during 1986-1996 (Gavrilov et al., 1990; Ilus and Ilus, 2000; Sax6n and Ilus, 2000; Smith

et al., 2000) Other rivers from the former USSR, i.e Neva, Luga, Narva, Dau- gava and Neman provided ca 2.6 TBq of 137Cs to the Baltic Sea It is reported that Swedish rivers have discharged ca 150 TBq of 137Cs into the Baltic Sea dur- ing 1986-1996 while contribution of the Oder River and smaller German rivers to the total radiocaesium activity has been evaluated at level of 10 TBq Totally, ca

300 TBq of 137Cs has been discharged by these rivers into the Baltic Sea The next sources of radionuclides, e.g 137Cs and 9~ are reprocessing plants in Western Europe providing since 1970s into the Baltic ca 150 TBq of 137Cs (Ilus and Ilus, 2000)

B CHEMICAL ELEMENTS AND RADIONUCLIDES (i) Classification of Chemical Elements and Radionuclides

Trace, minor and major elements

There are different classifications concerning the terminology used for groups

of pollutants in various environmental compartments According to Hopkin (1989) terminology of chemical elements as trace metals and heavy metals is not adequately defined The metals and metalloids (semi-metals) include all of the elements except the noble gases (Group 0) and H, B, C, N, O, E P, S, C1, Br, I and At To metalloids belong Si, Ge, As, Se, Sb and Te The Periodic Table is pre- sented in Table 1.1 (Morgan and Stumm, 1991) Groups Ia and IIa, i.e the

"s block" metals, form monovalent cations (alkali metal cations) and divalent cations (earth alkali cations), respectively Groups IIIb through VIb belong to

"p block" metal ions The classification of elements into A- and B-type metal cations is based on the number of electrons in the outer shell As can be seen in Table 1.2 type-A metal cations (hard acids) having the inert gas type (d ~ electron configuration form complexes mainly with F and O as donor atoms contained in ligands Molecules of H20 are more strongly attracted to these metals than are molecules of N H 3 and CN-; no reaction occurs also with S 2- in aqueous solution Addition of NH 3, alkali CN- and alkali S 2- produced difficulty soluble precipitates The hard Lewis acids (AI, Ti, Sn, Mn, Co, Cr, V and Ni) are termed lithophile because their mass excess in stream transport in respect to their atmospheric transport to the oceans The type-B metal ions (soft Lewis acids) have tendency

to coordinate preferentially with bases having I, S or N as donor atoms (Morgan and Stumm, 1991) These metals (Hg, As, Se, Sn, Pb) can be methylated and/or released to the atmosphere as vapours In contrast, the soft Lewis acids are re- markably accumulated in the natural environments as well as potentially hazard- ous to ecology and human health because of their tendency to react with soft bases (SH- and NH-groups in enzymes) According to Williams (1981) chemical elements are distributed in the biosphere depending on various acid-base affini-

TABLE 1.1

3roup VIIa

Heavy boundary divides metals and metalloids (dashed b o u n d q ) from non-metals

TABLE 1.2

Classification of metal ions After Morgan and Stumm (1991); modified

Type-A Metal Cations Transition-Metal Cations Type-B Metal Cations Electron configuration of inert

gas; low polarizability; "hard

Co 2+, Ni z+, Cu z+, Ti 3+, V 3+,

Cr 3+, Mn 3§ Fe 3+, Co 3+

Electron number corresponds

to Ni ~ Pd ~ and Pt ~ (10 or 12 outer shell electrons); low elec- tronegativity; high polar- izabili- ty; "soft spheres"; Cu §

Ag +, Au § T1 § Ga § Zn 2+, Cd 2+,

Hg 2+, pb 2+, Sn 2+, T13+, Au 3+,

In 3+, Bi 3+

According to PEARSON'S Hard and Soft Acids

All type-A metal cations plus

Cr 3+, Mn 3+, Fe 3+, Co 3+,

U O 2+, V O 2§

Also species such as BF 3, BCI 3,

SO a, RSO~, RPO~ CO 2, RCO §

of the chemical combination of metals and ligands, i.e the Lewis acids and bases

in organisms The cellular bases are predominantly S, N and O as donor atoms in molecules of H20 and solute bases, e.g OH-, HCO 3, HPO]- Among the acids are H +, cations of the essential metals such as Na, K, Mg, Cr, Mn, Fe, Co, Ni,

Cu, Zn, Mo as well as potentially toxic metals such as divalent Hg, CH3Hg +, Pb,

Cd, Cr, etc Some of the type-B metals belonging to the sulphur-seeking ("soft- soft") metals are the toxicants such as Hg, Pb, TI, as well as the essential proteine and enzyme metals, e.g Fe, Cu and Zn Cations of the metals such as Mg, Ca,

Be, A1, Sn, Ge and the lanthanides (showing tendency to exhibit "hard sphere" or A-type behaviour in their coordination compounds) are oxygen-seeking ('hard-

B CHEMICAL ELEMENTS AND RADIONUCLIDES 17

-hard') Since H § shows a high affinity for donor atoms such as S, N and O; hence fundamental significance plays value of pH in metal binding in the biota (Morgan and Stumm, 1991) The lanthanides with Sc (21) and Y (39) are classi- fied as the rare earth elements (REE) These elements with 3+ ions and decreas- ing radii, indicate strong ionic bonding and weaker covalent bonding characteris- tics The lanthanides show tendency to exhibit "hard sphere" or A-type properties

in their coordination compounds (Morgan and Stumm, 1991)

As can be seen in Table 1.3 trace elements are released into the atmosphere from natural and anthropogenic sources (fossil fuel combustion, cement produc- tion, extractive metallurgy etc.) It is found that Ag, As, Cu, Hg, Pb, Sb, Sn and

Zn are the most potentially hazardous elements on a global or regional scale (Ta- ble 1.4) In this Table the geochemical scale is defined as 'global' when the effect

of perturbation can be demonstrated at least in large part of the Northern Hemi-

TABLE 1.3

Natural and anthropogenic sources of atmospheric emissions' After Morgan and Stumm (1991); modified

Ele- Continen- Volcanic Volcanic Industrial Fossil Fuel

ment tal Dust Flux Gas Flux Particulate Flux

Total Emis- Atmospheric sions, Indus- Interference trial Plus Factor (%)b Fossil Fuel

a All fluxes are in units of 10Sg per year

b Atmospheric interference factor = [total emissions + (continental + volcanic fluxes)] x 100

sphere (Morgan and Stumm, 1991) Chemical elements are partitioned in the bi- ota by different acid-base affinities, i.e by their kinetics, spatial partitioning and

by temporal partitioning (Williams, 1981; Morgan and Stumm, 1991) One of im- portant aspects of metal toxicity is the chemical combination of metal ions and ligands (Lewis acids and bases) in organisms The cellular bases are predomi- nantly S, N and O donor groups, i.e H20 and solute bases The acids are as fol- lows: H +, the essential metal cations and potentially hazardous metals Among the essential metals are Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni and Zn while

to hazardous elements belong Ag, As, Bi, Cd, Cr, Cu, Hg, In, Pb, Sb, Se, Sn, T1 and Zn (Morgan and Stumm, 1991) The toxic elements (Hg, Pb, T1) and the es- sential protein and enzyme metals (Cu, Fe, Zn) are classified to the sulfur- seeking ("soft-soft") type-B metals To oxygen-seeking ("hard-hard") elements be- long H § (having strong affinity for all donors, S, N and O) as well as A1, Be, Ca,

Ge, Mg, Sb and the lanthanides (Morgan and Stumm, 1991)

Radionuclides

Radionuclides (isotopes, nuclides) present in the aquatic and terrestrial envi- ronment are classified as either of natural or anthropogenic in origin Naturally- occurring radionuclides occur in the different ecosystems with primordial and cos- mogenic provenience To the most abundant radionuclides belong 4~ members

of the U and Th chains (234U, 235U) 23au 226Ra, 21~ and 21~ and the cosmogenic species, i.e 3H and 14C (Ilus and Ilus, 2000)

Primary radionuclides

Primordial radionuclides are long-lived species have been ubiquites on the Earth since its formation, i.e ca 4.5 x 109 years ago (MacKenzie, 2000) The radionuclides 238U, 232Th and 235U are the parent members of the uranium, tho- rium and actino-uranium radioactive decay series, respectively (Riley, 1971): Uranium series

B CHEMICAL ELEMENTS AND RADIONUCLIDES 19 Actino-uranium series

235 U 7.1X 108y ,-" 231Th 25.6 hk 23~pa 3.43 x 104y 2 2 7 A c , 21.8y~ 227Th, 18.4d,

These series are consisted of nuclides with very different geochemical fate and hence the radionuclides in the marine environments are not in secular equilib- rium In particular, Th and Pa are rapidly removed from the sea to the sediments resulting in significant deviation from the equilibrium value The ratios of the concentrations of these both isotopes to that of U are much lower than the equi- librium values (0.05-0.2%) (Riley, 1971)

Cosmogenic radionuclides

A significant part of the cosmic rays reaching the earth has energies exceeding that binding the nuclei of atoms Cosmic ray-produced radionuclides, e.g 3H, l~ 14C, 26A1, 325i, 36C1 and 41Ca, are generated in the upper atmosphere due to absorption of cosmic ray energies by the nuclei of the atoms of atmospheric gases, e.g O 2, N 2 and Ar In consequence, they are fragmented to stable or unsta- ble nuclei lighter than the parent nuclide These cosmic ray-produced radionu- clides are transported to the lower atmosphere and next to the oceans and to the continents All of these radionuclides, e.g 325i and 14C, have been very useful as tracers of environmental processes (Riley, 1971; MacKenzie, 2000) An extensive overview of five decades of studies of cosmic ray produced nuclides in oceans has been presented by Lal (1999) It should be emphasised that human radiation ex- posure from man-made radionuclides constitutes an additional contribution to the natural dose from the background radiation, i.e cosmic rays as well as primordial and cosmic ray-produced radionuclides, resulting in a world average individual ex- posure of ca 2.5 mS yr -a (MacKenzie, 2000) The presently established limit by the ICRP (International Commission for Radiological Protection) for the allow- able maximum radiation dose from industrial releases of radionuclides is

1 mS yr -1 (MacKenzie, 2000)

Anthropogenic radionuclides

Anthropogenic-derived radionuclides are mainly released from several sources since the 1940s Major their sources in the environment are nuclear weapons, nu- clear power production, accidents, radioactive waste disposal, solid radioactive waste disposal and man-made radionuclides as tracers of environmental processes (Ilus and Ilus, 2000; MacKenzie, 2000) Fallout from nuclear weapons explosions represents the largest contribution of anthropogenic-derived radionuclides in the ecosystem In the detonation of a nuclear bomb, radioactive fission products are generated from primary fission of Z35U or 239pu The main radionuclides produced

in nuclear weapons explosions and released to the atmosphere are as follows: 3H,

14C, 54Mn ' 55Fe ' 85Kr ' 89Sr ' 90Sr ' 91y, 95Zr ' 103Ru ' 106Ru ' 125Sb ' 1311, 133Xe ' 134Cs ' 137Cs ' 14~ 14~Ce, 239Np, 238pu, 239pu, 24~ 241pu and 241Am These radionuclides are de- posited from the atmosphere to the surface of the earth as fallout comprising

TABLE 1.4

Perturbations of the geochemical cycles of metals by society The elements are grouped according to the scale for which such perturbations can be documented After Morgan and Stumm (1991); modi- fied

Scale of Perturbation Most Diagnostic Mo- Health

Environments bility Concern Global Regional Lo-

cal

Critical Pathway

+ a

(+)

E (+)

E ( + ) ( + ) ( + ) ( + ) ( + ) ( + )

E

E (+) (E)

E

E

E ( + ) ( + ) ( + )

E A r A?

9

F

9

F, W, A? W,F

F? F,W

F , W

A , W

A

B CHEMICAL ELEMENTS AND RADIONUCLIDES 21

(1) + significant perturbation' ( + ) possible perturbation; ( - ) enriched relative to crustal abun- dances, but the enrichment may not by anthropogenic; - no perturbation; ? not enough information;

c enhanced due to mobilization of crustal materials (soil, dust) (2) A air; Sd sediments (coastal, lake);

So soils; I ice cores; W surface waters; Gw groundwaters; H humans; Em emission studies (only listed when little geochemical information is available) (3) v volatile; s soluble; r soluble only under reduc- ing conditions; a mobile as alkylated organometallic s p e c i e s ; - not mobile (4) + toxic in excess; ( + ) toxic, but little data available; E essential, but toxic in excess (5) F food; W water; A air; - no signifi- cant exposure likely

a organometallic forms only

b hexavalent form volatile and toxic, trivalent form essential

c exposure through hand-to-mouth activity is critical for lead in children

d enriched relative to crustal abundance from fuel oil combustion (vanadium porphyrins)

components such as stratospheric (78%), local (12%) and tropospheric (10%) (MacKenzie, 2000) Since stratospheric fallout was globally dispersed and tropos- pheric fallout was mainly dispersed in the latitude of the nuclear test it is resulted

in low contaminant level on a global scale with concentration greater in the Northern Hemisphere than in the Southern Hemisphere (Cambray et al., 1982; MacKenzie, 2000) Large quantities of radionuclides were produced in under- ground nuclear weapons tests but incomplete report is available to estimate the long-term environmental consequences of such tests (MacKenzie, 2000) The total radiological impact of atmospheric nuclear weapons tests is estimated at level of

3 x 10 7 manSv (70% of 14C and other main contributors such as 137Cs, 9~ 95Zr

a n d l~ The bioaccumulative abilities of radionuclides depend on their bio- chemical properties as well as on the individual accumulation strategies of given organism for each nuclide Generally, radioactive isotopes of metals follow the metabolic pathways their stable counterparts, if they exist, although differences in atomic weight may be responsible for slight differences in relative rates of reac- tion resulting in metabolic kinetics These differences show tendency to be more significant for the isotopes with a low atomic weight, e.g H and C However, ra- dioactive isotopes are represented in organisms in the expected amounts corre- sponding to proper proportion to their stable isotopes The representation of arti- ficial radionuclides not having their stable counterparts in aquatic biota is de- pendent on the extent and pattern of their release into the outer medium, their both radioactive and the biological half-lives and on other biological features of the organism considered (Phillips and Rainbow, 1993) The heavier transuranic radioisotopes are, as rule, strongly adsorbed by external tissues which are directly exposed to the ambient waters, i.e the gills and exoskeleton Similar route is ob-

served for algae which are able to accumulate transuranic radioisotopes predomi- nantly by passive adsorption (Phillips and Rainbow, 1993) Nuclear power produc- tion is next source of radionuclides; their most releases to the environment from the nuclear fuel cycle occur in the uranium mining and the fuel reprocessing stages resulting in the emission of Z2ZRn to the atmosphere It makes a local po- tential health hazard Spent nuclear fuel contains significant amounts of fissile 235U and 239pu and different countries have adopted various policies with respect

to the fuel reprocessing (UNSCEAR, 1993) There have been numerous accidents concerning reactors and other nuclear facilities, certain satellites, nuclear weap- ons and large radiation sources The most significant incidents are described in the below section (iv)

(ii) Chemical Elements as Environmental Pollutants

Relationship between man and ecosystem health has been explored, espe- cially in respect to perturbed ecosystems (Table 1.4) This includes the pollution status of regions harmed by some catastrophes, large-scale pollution, environ- mental accidents and episodes etc High-risk groups consuming extremely high quantities of trace metals present in specific assortment of seafood or offal con- cern seriously sea-side populations Marine fish and shellfish may by the domi- nant dietary sources of Hg for local populations (US EPA, 1984; Mance, 1987; Von Burg and Greenwood, 1991; dos Santos et al., 2000; Gray et al., 2000; Maurice-Bourgoin et al., 2000) A spectacular example of aquatic pollution by

a toxic metal is the Minamata incident, commencing in 1953 Fish and bird mor- talities in waters of the partially landlocked Minamata Bay were observed in early 1950s Dogs, pigs and especially cats were also suffered from this incident Efflu- ents from the Chisso factory contained significant amounts of different chemical elements including both methyl-Hg and inorganic Hg; hence the principal path- way of Hg exposition of animals and humans at Minamata area was postulated to

be polluted seafood, i.e fish and shellfish (Tsubaki and Irukayama, 1977; Bertram

et al., 1985; Von Burg and Greenwood, 1991; Phillips and Rainbow, 1993; Ha- rada, 1995; Ninomiya et al., 1995; Akagi et al., 1998) By the end of 1974, 107 of

798 officially verified patients had died Other cases of Minamata disease (Ha- rada, 1978, 1995) were noted in Niigata, Japan, caused by the discharge of Hg in the effluents from electric industrial plant The consuming of polluted fish from local river caused this poisoning resulted in 6 deaths (Takizawa, 1979; Phillips and Rainbow, 1993) According to Tomiyasu et al (2000) the sediments from the Mi- namata Bay were consistently found to contain Hg at level that highly exceeded background level It is supposed that the Hg was mostly derived from the effluent from the chemical plant The surficial sediments enriched in Hg are not stable and apparently still moving even though 30 years have passed since the last dis- charge of polluted effluent (Tomiyasu et al., 2000) Amongst other incidents and accidents resulting in release of Hg compounds to the environment, the most sig-

B CHEMICAL ELEMENTS AND RADIONUCLIDES 23 nificant had place in the 1960s and early 1970s in Sweden, Canada and the United States, northern Iraq, Guatemala, Pakistan, Ghana (F6rstner and Witt- mann, 1983; Phillips and Rainbow, 1993; Akagi et al., 1995; Harada, 1996; Ha- rada et al., 1999) For instance, in 1960 was noted epidemic outbreak when 221 patients were hospitalised (Damluji, 1962) as a result of the use of ethyl-Hg fun- gicide in 1956 (Jalili and Abbasi, 1961) However, the most dramatic epidemic ever has been recorded took place in northern Iraq in 1971-1972; the people have been affected there by massive poisoning due to the ingestion of homemade bread prepared from wheat seed that had been treated with a methyl-Hg fungi- cide In consequence, the dressed seed was dumped in local rivers and lakes re- sulting in severe pollution of large area These combined events strongly affected

a huge part of local population; it is thought that 100,000-500,000 inhabitants have been suffering permanent disabilities (F6rstner and Wittmann, 1983; Phillips and Rainbow, 1993) According to Bakir et al (1973) 6530 patients were admitted

to hospitals where 459 died Based on epidemiological data it is indicated that over 2000 deaths occurred and more than 60,000 people were exposed (Green- wood, 1985; Von Burg and Greenwood, 1991)

Methylmercury in aquatic ecosystems is accumulated especially in fish constitut- ing a major public health problem (Wheatley and Wheatley, 2000; Pilgrim et al., 2000) Its levels in the hair of fishermen are described anticipating that they repre- sent the critical group for dietary exposure For instance, the concentrations of Hg (total and MeHg) in hair of fishermen from Kuwait were twice the WHO 'normal' level (2.0/zg g-l) (Al-Majed and Preston, 2000) The unlimited use of Hg in a gold mining process has resulted in the serious pollution of many aquatic and terrestrial ecosystems Such anthropogenic emissions occur in almost gold mining operations

in developing countries such as Brazil, Ecuador, Peru, Columbia, the Philippines and Tanzania (Akagi et al., 1995, 2000; Harada, 1996; Ikingura and Akagi, 1996; Harada et al., 1999; Rosa et al., 2000; van Straaten, 2000a, 2000b) Problem of large scale pollution has been and is still key topic and some of published papers (Pfeif- fer and Lacerda, 1988; Nriagu et al., 1992; Akagi et al., 1995; Maim et al 1995a, 1995b; Artaxo et al., 2000) presented abnormal levels of total mercury and meth- ylmercury in environmental compartments such as air, soil, bottom sediments, fish and plants as well as in human hair and urine in order to evaluate the extent of en- vironmental mercury pollution due to goldmining activities in the Amazon An av- erage of 63% of the Hg concentrations was associated with the gold mining activi- ties (Artaxo et al., 2000) Biomass burning in tropical forests also seems to have contributed significantly to the Hg release to the atmosphere Apptoximately 31%

of the Hg concentrations was associated with the vegetation fire component (Ar- taxo et al., 2000) Long-range air mass trajectory analyses indicate the possibility that Hg occurs in the Amazon basin over two main routes: to the South Atlantic, and to the Tropical Pacific, over the Andes (Artaxo et al., 2000)

Chemical composition of aerosol particles from direct emissions of vegetation fires in the Amazon Basin has been estimated by Yamasoe et al (2000) Global

emission flux estimates exhibited that biomass burning could be important source

of heavy metals and black carbon to the atmosphere It is estimated that savanna and tropical forest biomass burning could emit ca 1 Gg Cu yr -1, 3 Gg Zn yr -~ and 2.2 Tg black carbon to the atmosphere, i.e these values correspond to 2, 3 and 12%, respectively, of the global budget of these elements (Yamasoe et al., 2000) Episode involving the poisoning of local population by other trace elements than Hg was noted in 1947 in the Jintsu River basin in Japan (Yamagata and Shigematsu, 1970; Phillips and Rainbow, 1993) It is believed that principal cause

of the disease, named the Itai-itai syndrome were effluents enriched in Cd from

a zinc mine operated in this area As a result of this episode approximately 200 patients died prior 1966 (Phillips and Rainbow, 1993) In Zhejiang province, China, representing a highly exposed area, concentrations of Cd in rice were 50 times greater than those from control area (Nordberg et al., 1997) There was

a significant dose-response relationship between Cd in urine and fl2-microglobulin excretion in urine, as an indicator of renal dysfunction This report as first one concerns a dose-response association in the Chinese population group in Zheji- ang province

The nature of current anthropogenic sources of Hg is different than it was several decades ago Many of the most significant emitters in the past, e.g chlor- alkali industry, paint containing mercury additives and pharmaceuticals have been largely phased out with fossil fuel combustion and waste disposal remaining as the most significant recent sources (Sunderland and Chmura, 2000) Other exam- ple of toxic effect of chemical element to man is SO2-4 which has been used re- cently as an air pollution indicator in the epidemiological studies in Beijing, China (Zhang et al., 2000) Main sources of this pollutant in the Beijing atmos- phere are coal combustion, number of households using gas fuel, counts of motor vehicles and population density Epidemiological studies have demonstrated that the air pollution in Beijing is associated with reduced immune function of chil- dren, chronic obstructive pulmonary disease, a total mortality and mortality due

to cardiovascular disease, pulmonary heart disease, malignant tumor and lung cancer (Xu et al., 1994, 1995, 1995b; Zhang et al., 1995, 2000) Another environmentally-derived healthy problem named Keshan disease has been identi- fied in Jilin province, China This endemic cardiovascular disease is mainly caused

by low Se levels in the environment (Ma and Zhang, 2000) Jilin province is one

of the most seriously affected Chinese area by Keshan disease The annual aver- age incident rate of the disease is 90/100 000 and the rate of morbidity amounted

B C H E M I C A L ELEMENTS AND R A D I O N U C L I D E S 25 soil and dust is estimated at 10-12% The greatest concentration of Pb has been detected in tin can packaging, wheat bran, gelatine and sea fruit products, i.e flesh and frozen fish, molluscs and shellfish Pb poisoning holds first place among professional intoxication reflected by rising from 9.4% in 1991 to 11.6% in 1995 (Snakin and Prisyazhnaya, 2000) In a residential area of Greater Calcutta ca

50 000 people inhabit in the vicinity of lead factory in which are produced lead ingots and lead alloys Many people, especially children, are effected by Pb toxic- ity (Chatterjee and Banerjee, 1999) Nriagu et al (1996a, 1996b, 1997a, 1997b) provided first data pointing to childhood Pb poisoning as a growing public health problem in urban area of Africa The strong relationships were found between blood Pb levels in children and whether the family owned a car or lived in

a house on a tarred road The studies documented the silent epidemic of child- hood Pb poisoning in African cities and towns (Nriagu et al., 1996a, 1996b, 1997a, 1997b; Liggans and Nriagu, 1998) According to Shen et al (1996) in China, childhood Pb poisoning might be widely pervasive as a result of rapid industriali- sation and the use of leaded gasoline The harmful health effects of childhood Pb poisoning provide evidence that this absolutely preventable disease warrants con- siderable public attention in China (Shen et al., 1996) Increased risk estimates for lung cancer in Pb exposed smelter workers have been demonstrated by Englyst et al (2001) However, considerable As exposure also had place in most

of the lung cancer cases In this multifactorial exposure it has, however, not possible to distinguish the carcinogenic effects caused by Pb and As but a possible interaction between these metals may be involved in explaining the carcinogenic risks

The deleterious effects of tributyltin (TBT), representing the most toxic form among Sn compounds, were the first indicated in Arcachon Bay, France, as the 'TBT problem' at the end of the 1970s (Alzieu, 1986, 2000) As a result of TBT releasing by antifouling paints to the area was shell abnormalities and reduced growth and settlement in oysters, Crassostrea gigas, cultured in the vicinity of ma- rinas In much polluted water, the production of the oysters was severely affected

by a complete lack of reproduction resulted in a strong decline in the marketable value of the remaining stock (Alzieu, 2000) Imposex, i.e the development of male sexual characteristics in female marine mesogastropods and neogastropods caused by TBT pollution, is a widespread phenomenon which has concerned sev- eral coastal species and more recently also offshore species (Evans et al., 1995,

1996, 2000c; Minchin et al., 1995, 1997; Tester and Ellis, 1995; Huet et al., 1996; Skarph6dinsd6ttir et al., 1996; Smith, 1996; Morgan et al., 1998; Poloczanska and Ansell, 1999; Santos et al., 2000; Shim et al., 2000; Hung et al., 2001) Later regu- lations prohibiting the use of TBT-based antifoulants on vessels less than 25 rn in length have been highly effective in reducing TBT levels in coastal waters How- ever, larger vessels are still responsible for releasing of TBT and major harbours continue to be hot-spots of pollution (Evans and Nicholson, 2000) Therefore, en- vironmental impact of TBT in coastal waters, microbial interaction, detoxification,