Table Of ContentLecture Notes ni
Earth Sciences
detidE yb Bhattacharji, Somdev Gerald .M ,namdeirF
Horst .J Neugebauer dna Adolf Seilacher
11
Lars Landner ).dE(
Speciation fo Metals ni Water,
Sediment dna Soil Systems
sgnideecorP of na ,pohskroW lanoitanretnI
,ennuS October 15-16, 6891
Springer-Verlag
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Dr. Lars Landner
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PREFACE
It is to-day generally recognized by environmental scientists that the parti-
cular behaviour of trace metals in the environment is determined by their specific
physico-chemical forms rather than by their total concentration. With the intro-
duction, several years ago, of atomic absorption spectrometry at many laboratories
involved in environmental studies, a technique for simple, rapid and cheap determi-
nation of total metal concentrations in environmental samples became available.
As a consequence, there is a plethora of scientific papers and reports where metal
concentrations in the environment are only reported as total concentrations.
It appears that the simplicity of making accurate determinations of total metal
contents in water, sediment and biological samples has somewhat masked the need
for improved knowledge about the various forms of metals occurring in the environ-
ment as well as the bioavailahility of these forms. In other words, the need for
metal speciation in studies of metals in the environment does not seem to have
become obvious to most environmental scientists until relatively recently. As
a matter of fact, it was only in the middle of the 1970s that the first systematic
attempts were made to obtain information about the various metal species occurring
in environmental samples.
During the last ten years, however, a revolutionary change of attitude towards
the importance of metal speciation has occurred and considerable research effort
has been devoted by environmental scientists to measuring the concentrations of
biologically important trace metals in surface waters. There is currently an
increasing effort to couple the development of chemical analytical techniques
to process-related biological problems. Concurrently, a new focus is being imposed
on ecological impact studies, that of determining which active trace metal species
merit the most intensive research from the standpoint of environmental pertur-
bation. Current efforts are directed towards the development of chemical speciation
schemes which can be related directly to measures of bioavailability (i).
This considerable growth of interest in the field of metal speciation has
resulted, during the last few years, in the organisation of a number of workshops
and seminars dealing partly or exclusively with chemical speciation. The first
one in this new category of international scientific meetings seems to have been
the NATO Workshop on "Trace Element Speciation in Surface Waters and Its Ecological
Implications", held in Nervi, Italy, in November 1981 (2). Later, the Dahlem
VI
Conferences, Berlin, took up the same topic when a workshop on "The Importance
of Chemical Speciation in Environmental Processes" was organised in September
1984 (3). It might be pertinent to mention in this context also the International
Seminar on "Speciation, Separation and Recovery of Metals", held in 1986 (4).
When the present workshop on "The Speciation of Metals in Water, Sediment and
Soil Systems" was organised in Sunne, Sweden, it was recognised that research
in this field requires a multidisciplinary team approach. Therefore, scientists
with many different backgrounds - engineers, physicists, hydrologists, geologists,
analytical chemists, biologists and ecologists - were invited with the aim of
forcing them to find a common language and, as far as possible, a mutual under-
standing. The purpose of the workshop was to review and evaluate the recent scien-
tific progress in the field of metal speciation and related subjects and to discuss,
from the various perspectives of the participants, priorities for planning of
future research and possible areas of common interest and cooperation. The programme
of the workshop included critical reviews of the latest progress in the development
of analytical methods for separation and determination of various metal species
in water, sediment and soil, a discussion of why and when metal speciation is
to be recommended, a review of the major environmental factors influencing the
distribution and transformation of metal species, and a discussion of the implica-
tions of this approach to metal research for environmental planning and management.
The Sunne Workshop, which was attended by about 30 scientists from several
different countries, started with presentations of five major background papers,
followed by a number of contributed papers. The integral text of all these contri-
butions is contained in this volume. During the second day of the workshop, the
participants gathered in four separate Working Groups to discuss various scenarios
wherein speciation of metals would be useful or necessary. The development of
adequate analytical techniques, both for routine work and for in-depth scientific
studies, was discussed and future needs were considered. A particularly fruitful
aspect of these discussions was the close contact achieved between the analytical
chemists, who develop and run the analytical procedures, and the biologists, who
make use of the analytical data so as to interpret the bioavailability and effects
of metals in the environment. It became quite clear that a much closer cooperation
between the two sides is necessary - and possible - to further our knowledge on
the distribution and effects of metals in the environment.
REFERENCES
.I Leppard, G.G. Trace element speciation and the quality of surface waters:
An introduction to the scope for research. In: ref. :2 I-i0.
.2 Leppard, G.G., .dE Trace Element Speciation in Surface Waters and Its Ecolo-
gical Implications. Proc. NATO Advanced Research Workshop, Nov. 2-4, 1981,
Nervi, Italy, (New York: Plenum Press, 1983).
.3 Bernhard, M., F.E. Brinckman, and P.S. Sadler, Eds. The Importance of Chemical
Speciation in Environmental Processes. Dahlem Conferences, September
2-7, 1984, Berlin. (Berlin: Springer Verlag, 1986).
.4 Patterson, J.W., Ed. Speciation, Separation and Recovery of Metals. Proc.
of an International Seminar. (Chelsea: Lewis Publ., 1986).
TABLE OF CONTENTS
INTRODUCTION
The Metal Conference in Athens, 1985: A Growing Interest in Metal
Speciation; A Review
Rudolf Reuther ............................................
SECTION :I ANALYTICAL TECHNIQUES FOR SPECIATION OF METALS
DETECTION AND ROLE OF MOBILE METAL SPECIES
Metal Speciation in Solid Wastes - Factors Affecting Mobility
Ulrich FSrstner ........................................... 13
Analytical Techniques in Speciation Studies
Brit Salbu ................................................ 43
Approaches to Metal Speciation Analysis in Natural Waters
G.M.P. Morrison ........................................... 55
Metal Fractionation by Dialysis - Problems and Possibilities
Hans Borg ................................................. 75
Trace Element Speciation in Natural Waters Using Hollow-Fiber
Ultrafiltration
E. Lydersen, H.E. Bj~rnstad, B. Salbu and A.C° Pappas ..... 85
The Importance of Sorption Phenomena in Relation to Trace Element
Speciation and Mobility
.B Allard, K. H~kansson and .S Karlsson ................... 99
SECTION :2 BIOLOGICAL IMPLICATIONS OF METAL SPECIATION
Testing the Bioavalaibility of Metals in Natural Waters
Peter Pgrt ................................................ 115
Case Studies on Metal Distribution and Uptake in Biota
Olle Grahn and Lars H~kanson .............................. 127
Effects of pH on the Uptake of Copper and Cadmium by Tubificid
Worms (Oligocha'eta) in Two Different Types of Sediment
Anders Broberg and Gunilla Lindgren ...................... 145
Aluminium Impact on Freshwater Invertebrates at Low pH: A Review
Jan Herrmann .............................................. 157
SECTION 3
Summary of Working Group Reports
Lars Landner .............................................. 179
APPENDIX
The Workshop Participants ....................................... 189
Introduction
THE METAL CONFERENCE IN ATHENS, 1985 A : GROWING INTEREST IN METAL SPECIATION
A REVIEW
Rudolf Reuther
Swedish Environmental Research Group
Fryksta, S-665 O0 KIL
The 5th International Conference on Heavy Metals in the Environment, which took
place in Athens (Greece), in September 1985, was called, in advance, one of the
biggest scientific meetings in the field of environmental research held in Europe.
Looking at the great number of authors (1112) and papers presented (433) from all
over the world, the conference framework was indeed impressive. Its real importance
for our future understanding of the environmental impact of heavy metals, as a
basis for an effective health and environmental protection policy, has still to
be eyaluated. The aim of the present review is not to assess the importance of
the conference, but just to examine to what extent the papers presented were dealing
with metal speciation. Furthermore, it will discuss the general approaches to metal
speciation used in the middle of the 1980s, as well as the precise methods selected
for separation and detection of various metal species.
Almost one fourth of all papers published in the Conference Proceedings (2 vo-
lumes, 1337 pp) dealt with speciation of metals. Some of the papers were directed
to the determination of at least one analytically defined chemical form (e g tetra-
alkyllead), others used a more general approach, where groups of species were sepa-
rated (e g low and high molecular weight compounds) (I).
However, the use of the term "species" still seems to cause some confusion:
generally it was used in a descriptive manner and not as a measurable quantity
related to e g the "reactivity" of the metal in the environment. So far we may
rely upon the definition suggested by the participants of the Dahlem Workshop on
"The Importance of Chemical Speciation in Environmental Processes", where a "species"
is understood as the "molecular representation of a specific form of an
element" (2).
An overview of the frequencies )x( of environmental samples and metals studied,
as well as separation and detection methods applied in the work accounted for in
the Conference proceedings, is presented in Table .I
Table I. The frequency (x) of environmental matrices, metals, separation and
detection methods used in speciation studies.
Enviranmentel xirtaM M e s I a t Separation sdohteM Detection Analysis
o lacigoloib snemiceps )x42( o Cu (37x) o lacinahcem ,noitartlif( (9x) S A A )x93(
o retawhserf )x51( o Pb (34x) centrlfugatlon, seLvlng) V S A (7x)
o etsaw sdllas )x41( o Cd (32x) o tnevlos noitcartxe (8x) D R X (5x)
o marine sediments )x31( o Zn (32x) o egnahcxe-noI and gel )x31( P C I (5x)
o lios atartsbus )xOf( o Fe (20x) yhpargotamorhc oidar recart (3x)
o cirehpsomta )x9(stneutitsnoc o Ni (13x) o sag yhpargotamorhc )xOf( N A A (3x)
o eniram retaw )x4( o Cr (11x) o yhpargotamorhCCLPH (3x) E S I (3x)
o freshwater sediments )x4( o Hg (11x) o lacimehc noitcartxe )x72( MS (3x)
o retaw etsaw )xI( o AI (Sx) o lohcetaC ,telolv ATDE T~Js~ (2x)
o oC (7x) and hatho phananthro- ZSR (2x)
o Sn (5x) Ltne complexation,
o As (4x) ,gnllladomlac!mehc o M~ssbauer spectroscopy, I~R,
o Ca, ~, ~, den~ity and magnetic PIX:, EDX; DPP, C3V, ,AD,.F FPH,
K, V, U, T1, separation, sorptton photoapectroscopy, thermogra-
,iS ,iT eB experiments vity, magaetometry, derivative
spectroscopy
Most concern was dedicated to biological samples (e g cells, tissues, organs,
whole organisms: 24 x), freshwater samples (15 x), solid wastes (sewage sludge,
mine tailings, dredged material: 14 x), marine-estuarine sediments (13 x), soil
substrates (I0 x) and airborne constituents (e g dust, fly ash, aerosols, vapour,
atmospheric water: 9 x). However, no speciation studies among those presented in
the proceedings were dealing with colloidal systems.
Speciated metal s
The heavy metals copper (37 x), lead (34 x), cadmium (32 x) and zinc (32 x)
were most frequently subject to speciation procedures, both in laboratory and model-
ling studies (1,:475, ~:394") as well as in routine environmental monitoring (!:380,
!:585, ~:34, ~:443, ~:454, ~:559). The great interest in these metals was mostly
related to their toxic character and their wide-spread occurrence in many natural
systems as a result of releases from a multitude of human activities (e g com-
bustion, ore smelting, metal plating).
Speciation studies with iron (20 x) and manganese (14 x), mainly with respect
to their oxidic-hydroxidic forms, have been undertaken because of their well-known
implications in soil weathering and sedimentary processes. These metals might act
both as mobile scavengers for trace metals in solution and as an energy source
for certain bacteria (e g Thiobacillus ferroxidans, see !:246, !:266).
The speciation of aluminium (8 x) was generally attributed to its well estab-
* see Conference Proceedings, vol.: page
