Chromatographic Analysis of Invironment

Chromatographic Analysis
of the Environment
Third Edition

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com

CHROMATOGRAPHIC SCIENCE SERIES
A Series of Textbooks and Reference Books
Editor: JACK CAZES

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.

19.
20.

Dynamics of Chromatography: Principles and Theory,
J. Calvin Giddings
Gas Chromatographic Analysis of Drugs and Pesticides,
Benjamin J. Gudzinowicz
Principles of Adsorption Chromatography: The Separation
of Nonionic Organic Compounds, Lloyd R. Snyder
Multicomponent Chromatography: Theory of Interference,
Friedrich Helfferich and Gerhard Klein
Quantitative Analysis by Gas Chromatography, Josef Novák
High-Speed Liquid Chromatography, Peter M. Rajcsanyi
and Elisabeth Rajcsanyi
Fundamentals of Integrated GC-MS (in three parts),
Benjamin J. Gudzinowicz, Michael J. Gudzinowicz,
and Horace F. Martin
Liquid Chromatography of Polymers and Related Materials,
Jack Cazes
GLC and HPLC Determination of Therapeutic Agents (in three parts),
Part 1 edited by Kiyoshi Tsuji and Walter Morozowich, Parts 2 and 3
edited by Kiyoshi Tsuji
Biological/Biomedical Applications of Liquid Chromatography,
edited by Gerald L. Hawk
Chromatography in Petroleum Analysis, edited by Klaus H. Altgelt
and T. H. Gouw
Biological/Biomedical Applications of Liquid Chromatography II,
edited by Gerald L. Hawk
Liquid Chromatography of Polymers and Related Materials II,
edited by Jack Cazes and Xavier Delamare

Introduction to Analytical Gas Chromatography: History, Principles,
and Practice, John A. Perry
Applications of Glass Capillary Gas Chromatography, edited by
Walter G. Jennings
Steroid Analysis by HPLC: Recent Applications, edited by
Marie P. Kautsky
Thin-Layer Chromatography: Techniques and Applications,
Bernard Fried and Joseph Sherma
Biological/Biomedical Applications of Liquid Chromatography III,
edited by Gerald L. Hawk
Liquid Chromatography of Polymers and Related Materials III,
edited by Jack Cazes
Biological/Biomedical Applications of Liquid Chromatography,
edited by Gerald L. Hawk

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com

21. Chromatographic Separation and Extraction with Foamed Plastics
and Rubbers, G. J. Moody and J. D. R. Thomas
22. Analytical Pyrolysis: A Comprehensive Guide, William J. Irwin
23. Liquid Chromatography Detectors, edited by Thomas M. Vickrey
24. High-Performance Liquid Chromatography in Forensic Chemistry,
edited by Ira S. Lurie and John D. Wittwer, Jr.
25. Steric Exclusion Liquid Chromatography of Polymers, edited by
Josef Janca
26. HPLC Analysis of Biological Compounds: A Laboratory Guide,
William S. Hancock and James T. Sparrow

27. Affinity Chromatography: Template Chromatography of Nucleic
Acids and Proteins, Herbert Schott
28. HPLC in Nucleic Acid Research: Methods and Applications,
edited by Phyllis R. Brown
29. Pyrolysis and GC in Polymer Analysis, edited by S. A. Liebman
and E. J. Levy
30. Modern Chromatographic Analysis of the Vitamins, edited by
André P. De Leenheer, Willy E. Lambert, and Marcel G. M. De Ruyter
31. Ion-Pair Chromatography, edited by Milton T. W. Hearn
32. Therapeutic Drug Monitoring and Toxicology by Liquid
Chromatography, edited by Steven H. Y. Wong
33. Affinity Chromatography: Practical and Theoretical Aspects,
Peter Mohr and Klaus Pommerening
34. Reaction Detection in Liquid Chromatography, edited by Ira S. Krull
35. Thin-Layer Chromatography: Techniques and Applications,
Second Edition, Revised and Expanded, Bernard Fried
and Joseph Sherma
36. Quantitative Thin-Layer Chromatography and Its Industrial
Applications, edited by Laszlo R. Treiber
37. Ion Chromatography, edited by James G. Tarter
38. Chromatographic Theory and Basic Principles, edited by
Jan Åke Jönsson
39. Field-Flow Fractionation: Analysis of Macromolecules and Particles,
Josef Janca
40. Chromatographic Chiral Separations, edited by Morris Zief
and Laura J. Crane
41. Quantitative Analysis by Gas Chromatography, Second Edition,
Revised and Expanded, Josef Novák
42. Flow Perturbation Gas Chromatography, N. A. Katsanos
43. Ion-Exchange Chromatography of Proteins, Shuichi Yamamoto,

Kazuhiro Naka-nishi, and Ryuichi Matsuno
44. Countercurrent Chromatography: Theory and Practice,
edited by N. Bhushan Man-dava and Yoichiro Ito
45. Microbore Column Chromatography: A Unified Approach
to Chromatography, edited by Frank J. Yang
46. Preparative-Scale Chromatography, edited by Eli Grushka
47. Packings and Stationary Phases in Chromatographic Techniques,
edited by Klaus K. Unger
48. Detection-Oriented Derivatization Techniques in Liquid
Chromatography, edited by Henk Lingeman
and Willy J. M. Underberg
49. Chromatographic Analysis of Pharmaceuticals, edited by
John A. Adamovics

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com

50. Multidimensional Chromatography: Techniques and Applications,
edited by Hernan Cortes
51. HPLC of Biological Macromolecules: Methods and Applications,
edited by Karen M. Gooding and Fred E. Regnier
52. Modern Thin-Layer Chromatography, edited by Nelu Grinberg
53. Chromatographic Analysis of Alkaloids, Milan Popl, Jan Fähnrich,
and Vlastimil Tatar
54. HPLC in Clinical Chemistry, I. N. Papadoyannis
55. Handbook of Thin-Layer Chromatography, edited by Joseph Sherma
and Bernard Fried
56. Gas–Liquid–Solid Chromatography, V. G. Berezkin

57. Complexation Chromatography, edited by D. Cagniant
58. Liquid Chromatography–Mass Spectrometry, W. M. A. Niessen
and Jan van der Greef
59. Trace Analysis with Microcolumn Liquid Chromatography,
Milos KrejcI
60. Modern Chromatographic Analysis of Vitamins: Second Edition,
edited by André P. De Leenheer, Willy E. Lambert, and Hans J. Nelis
61. Preparative and Production Scale Chromatography, edited by
G. Ganetsos and P. E. Barker
62. Diode Array Detection in HPLC, edited by Ludwig Huber
and Stephan A. George
63. Handbook of Affinity Chromatography, edited by Toni Kline
64. Capillary Electrophoresis Technology, edited by Norberto A. Guzman
65. Lipid Chromatographic Analysis, edited by Takayuki Shibamoto
66. Thin-Layer Chromatography: Techniques and Applications:
Third Edition, Revised and Expanded, Bernard Fried
and Joseph Sherma
67. Liquid Chromatography for the Analyst, Raymond P. W. Scott
68. Centrifugal Partition Chromatography, edited by Alain P. Foucault
69. Handbook of Size Exclusion Chromatography, edited by Chi-San Wu
70. Techniques and Practice of Chromatography, Raymond P. W. Scott
71. Handbook of Thin-Layer Chromatography: Second Edition,
Revised and Expanded, edited by Joseph Sherma and Bernard Fried
72. Liquid Chromatography of Oligomers, Constantin V. Uglea
73. Chromatographic Detectors: Design, Function, and Operation,
Raymond P. W. Scott
74. Chromatographic Analysis of Pharmaceuticals: Second Edition,
Revised and Expanded, edited by John A. Adamovics
75. Supercritical Fluid Chromatography with Packed Columns:
Techniques and Applications, edited by Klaus Anton

and Claire Berger
76. Introduction to Analytical Gas Chromatography: Second Edition,
Revised and Expanded, Raymond P. W. Scott
77. Chromatographic Analysis of Environmental and Food Toxicants,
edited by Takayuki Shibamoto
78. Handbook of HPLC, edited by Elena Katz, Roy Eksteen,
Peter Schoenmakers, and Neil Miller
79. Liquid Chromatography–Mass Spectrometry: Second Edition,
Revised and Expanded, Wilfried Niessen
80. Capillary Electrophoresis of Proteins, Tim Wehr,
Roberto Rodríguez-Díaz, and Mingde Zhu

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com

81. Thin-Layer Chromatography: Fourth Edition, Revised and Expanded,
Bernard Fried and Joseph Sherma
82. Countercurrent Chromatography, edited by Jean-Michel Menet
and Didier Thiébaut
83. Micellar Liquid Chromatography, Alain Berthod
and Celia García-Alvarez-Coque
84. Modern Chromatographic Analysis of Vitamins: Third Edition,
Revised and Expanded, edited by André P. De Leenheer,
Willy E. Lambert, and Jan F. Van Bocxlaer
85. Quantitative Chromatographic Analysis, Thomas E. Beesley,
Benjamin Buglio, and Raymond P. W. Scott
86. Current Practice of Gas Chromatography–Mass Spectrometry,
edited by W. M. A. Niessen

87. HPLC of Biological Macromolecules: Second Edition, Revised
and Expanded, edited by Karen M. Gooding and Fred E. Regnier
88. Scale-Up and Optimization in Preparative Chromatography:
Principles and Bio-pharmaceutical Applications, edited by
Anurag S. Rathore and Ajoy Velayudhan
89. Handbook of Thin-Layer Chromatography: Third Edition, Revised
and Expanded, edited by Joseph Sherma and Bernard Fried
90. Chiral Separations by Liquid Chromatography and Related
Technologies, Hassan Y. Aboul-Enein and Imran Ali
91. Handbook of Size Exclusion Chromatography and Related
Techniques, Second Edition, edited by Chi-San Wu
92. Handbook of Affinity Chromatography, Second Edition, edited by
David S. Hage
93. Chromatographic Analysis of the Environment, Third Edition,
edited by Leo M. L. Nollet

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com

Chromatographic Analysis
of the Environment
Third Edition

edited by

Leo M. L. Nollet
Hogeschool Gent
Ghent, Belgium

Boca Raton London New York

A CRC title, part of the Taylor & Francis imprint, a member of the
Taylor & Francis Group, the academic division of T&F Informa plc.

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com

Published in 2006 by
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2006 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group
No claim to original U.S. Government works
Printed in the United States of America on acid-free paper
10 9 8 7 6 5 4 3 2 1
International Standard Book Number-10: 0-8247-2629-4 (Hardcover)
International Standard Book Number-13: 978-0-8247-2629-4 (Hardcover)
Library of Congress Card Number 2005048464
This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with
permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish
reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials
or for the consequences of their use.
No part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or
other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information

storage or retrieval system, without written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copyright.com
( or contact the Copyright Clearance Center, Inc. (CCC) 222 Rosewood Drive, Danvers, MA
01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For
organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged.
Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for
identification and explanation without intent to infringe.
Library of Congress Cataloging-in-Publication Data
Chromatographic analysis of the environment / [edited by] Leo M.L. Nollet.--3rd ed.
p. cm.
Prev. ed. edited by Robert L. Grob.
Includes bibliographical references and index.
ISBN 0-8247-2629-4 (alk. paper)
1. Chromatographic analysis. 2. Environmental chemistry. I. Nollet, Leo M.L., 1948- II. Grob, Robert
Lee.
QD79.C4C48 2005
628.5'028'7--dc22

2005048464

Visit the Taylor & Francis Web site at

Taylor & Francis Group
is the Academic Division of Informa plc.

© 2006 by Taylor & Francis Group, LLC

and the CRC Press Web site at

www.pdfgrip.com

Preface
Since the publication of the second edition in 1983 tremendous changes have occurred in the field of
environmental analytical chemistry. These changes have produced numerous approaches to sampling the
air we breathe, the water we drink, and the soil in which we grow our fruits and vegetables. More
dramatically, the changes have brought to the forefront the manner in which we regard waste problems.
So writes Professor R.L. Grob, editor of the first and second edition.
Indeed since the 1980s tremendous changes have occurred; the most striking changes are
miniaturization and automation of sample procedures and analytical techniques.
The philosophy of this third edition, totally different from the two former editions, is discussing most
parameters of the different compartments of the environment (air, water, soil, waste) in a uniform
structure: sample preparation techniques, separation methods, and detection modes. Most of the data are
compiled in tables. Where necessary figures are added to elucidate the text.
The topic of sampling is discussed in two chapters. In chapter 1 attention is paid to specific aspects of
sampling in the environment, whereas in chapter 2 the different sample preparation methods are
explained. Chapters 3 and 4 complete the book with discussions on theoretical and practical aspects of
chromatographic separations and detection methods. Finally, the importance of data processing is
detailed in chapter 5.
In the second part, comprising chapters 6 through 32, the different, major and minor elements of the
environment are dealt with. Special attention is given to volatile organic carbons (VOCs), peroxyacyl
nitrates (PANs), and endocrine disrupting chemicals (EDCs). Of course, all other discussed
environmental parameters are of equal importance.
All readers are aware that the project of preparing a text of this type is not possible without the
assistance, support, and cooperation of many people. The third edition is certainly no exception. The
finalization of such an undertaking can be frustrating in the least. The most important persons are the
many authors, without whose hard work a task of this magnitude is not possible. I thank them very much.
For the understanding and patience, I wish to thank my wife and family.
I would like to dedicate this work to a fine friend of mine, Jose´ B., who died last year of

cancer—a terrible disease. I hope people will be aware of the importance of good quality air, water,
and soil.
Leo M.L. Nollet

ix

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com

The Editor
Leo M.L. Nollet is a professor of biotechnology at Hogeschool Gent, Ghent, Belgium. The author and
co-author of numerous articles, abstracts, and presentations, Dr. Nollet is the editor of the three-volume
Handbook of Food Analysis, Second Edition, Handbook of Water Analysis and Food Analysis by HPLC,
Second Edition (all titles by Marcel Dekker Inc.).
His research interests include air and water pollution, liquid chromatography, and applications of
different chromatographic techniques in food, water, and environmental parameters analysis.
He received M.S. (1973) and Ph.D. (1978) degrees in biology from the Katholieke Universiteit
Leuven, Belgium.

xi

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com

Table of Contents
Chapter 1 The Sampling Process .............................................................................................. 1

Munro R. Mortimer and Jochen F. Muăller

Chapter 2 Sample Preparation for Chromatographic Analysis
of Environmental Samples ..................................................................................... 31
Claudia E. Domini, Dimitar Hristozov, Beatriz Almagro, Iva´n P. Roma´n,
Soledad Prats, and Antonio Canals

Chapter 3 Chromatography ................................................................................................... 133
Tadeusz Go´recki

Chapter 4 Detection in Chromatography .............................................................................. 177
Antoine-Michel Siouffi

Chapter 5 Chemometrics in Data Analysis ........................................................................... 221
Riccardo Leardi

Chapter 6 Major Air Components ......................................................................................... 243
Wei-Hsin Chen and Jau-Jang Lu

Chapter 7 The Determination of Phosphates in Environmental Samples
by Ion Chromatography ....................................................................................... 263
Brett Paull, Leon Barron, and Pavel Nesterenko

Chapter 8 Characterization of Organic Matter from Air, Water, Soils,
and Waste Material by Analytical Pyrolysis ....................................................... 287
Declan Page

Chapter 9 Monitoring of Nitrogen Compounds in the Environment,
Biota, and Food .................................................................................................... 311
S. Jayarama Reddy

Chapter 10 Sulfur Compounds .............................................................................................. 343
Kerstin Beiner and Peter Popp

Chapter 11 Amines ................................................................................................................ 377
Anna Pielesz
xiii

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
xiv

Table of Contents

Chapter 12 N-Nitrosamines ................................................................................................... 419
Ana Marı´a Afonso Perera

Chapter 13 Organic Acids ..................................................................................................... 453
Sigrid Peldszus

Chapter 14 BTEX .................................................................................................................. 513
Nacho Martı´n Garcı´a and Leo M.L. Nollet

Chapter 15 Polycyclic Aromatic Hydrocarbons ................................................................... 555
Audrey E. McGowin

Chapter 16 Volatile Organic Compounds in
the Atmosphere .................................................................................................. 617

Paul V. Doskey

Chapter 17 Halogenated VOCs ............................................................................................. 645
Filip D’hondt, Haytham Chahin, and Mohammad Ghafar

Chapter 18 Polychlorobiphenyls ........................................................................................... 667
Alessio Ceccarini and Stefania Giannarelli

Chapter 19 Peroxyacyl Nitrates, Organic Nitrates, and Organic
Peroxides (AIR) .................................................................................................. 711
Jeffrey S. Gaffney and Nancy A. Marley

Chapter 20 Speciation in Environmental Samples ............................................................... 743
Willy Baeyens, Marjan De Gieter, Martine Leermakers, and Isabelle Windal

Chapter 21 Isocyanates ......................................................................................................... 779
Paal Molander

Chapter 22 Chromatographic Analysis of Insecticides Chlorinated
Compounds in Water and Soil ........................................................................... 803
Michela Maione and Filippo Mangani

Chapter 23 Organophosphorus Compounds in Water, Soils, Waste,
and Air ................................................................................................................ 841
Roger Jeannot and Thierry Dagnac

Chapter 24 Chromatographic Determination of Carbamate Pesticides
in Environmental Samples ................................................................................. 889
Evaristo Ballesteros Tribaldo

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
Table of Contents

xv

Chapter 25 Analysis of Urea Derivative Herbicides in Water and Soil .............................. 935
Sara Bogialli, Roberta Curini, Antonio Di Corcia, and Manuela Nazzari

Chapter 26 Herbicide Residues in the Environment ............................................................ 977
Thierry Dagnac and Roger Jeannot

Chapter 27 Oil and Petroleum Product Fingerprinting Analysis
by Gas Chromatographic Techniques .............................................................. 1027
Zhendi Wang and Merv Fingas

Chapter 28 Phthalate Esters ................................................................................................ 1103
Maria Llompart, Carmen Garcı´a-Jares, and Pedro Landı´n

Chapter 29 Humic Substance .............................................................................................. 1155
Fengchang Wu and Congqiang Liu

Chapter 30 Surfactants ........................................................................................................ 1173
Bjoern Thiele

Chapter 31 Determination of Flame Retardants in Environmental
Samples ............................................................................................................. 1199
Tuulia Hyoătylaăinen

Chapter 32 Chromatographic Analysis of Endocrine Disrupting Chemicals
in the Environment ........................................................................................... 1241
Guang-Guo Ying

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com

Contributors
Beatriz Almagro
Department of Analytical Chemistry,
Nutrition and Bromatology
University of Alicante
Alicante, Spain
Willy Baeyens
Department of Analytical and Environmental
Chemistry
Vrije Universiteit Brussel
Brussels, Belgium
Leon Barron
National Centre for Sensor Research
School of Chemical Sciences
Dublin City University
Dublin, Ireland
Kerstin Beiner
Centre for Environmental Research
Leipzig-Halle
Department of Analytical Chemistry

Leipzig, Germany
Sara Bogialli
Dipartimento di Chimica
Universita` La Sapienza
Roma, Italy
Antonio Canals
Department of Analytical Chemistry,
Nutrition and Bromatology
University of Alicante
Alicante, Spain
Alessio Ceccarini
Department of Chemistry and Industrial
Chemistry
University of Pisa
Pisa, Italy

Haytham Chahin
High Institute for Environmental
Research
Lattakia, Syria
Wei-Hsin Chen
Department of Marine Engineering
National Taiwan Ocean University
Keelung, Taiwan
Antonio Di Corcia
Dipartimento di Chimica
Universita` La Sapienza
Roma, Italy
Roberta Curini
Dipartimento di Chimica

Universita` La Sapienza
Roma, Italy
Thierry Dagnac
BRGM Laboratory of
Enviromental Chemistry
Orleans, France
Filip D’hondt
Peakadilly Technologiepark
Gent, Belgium
Claudia E. Domini
Laboratorio FIA
Departamento de Quı´mica
Universidad Nacional del Sur.
Bahı´a Blanca, Argentina
Paul V. Doskey
Environmental Research Division
Argonne National Laboratory
Argonne, Illinois, USA
xvii

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
xviii

Merv Fingas
Emergencies Science and
Technology Division
Environmental Technology Centre

Environment Canada, Ottawa
Ontario, Canada

Contributors

Tuulia Hyoătylaăinen
Department of Chemistry
Laboratory of Analytical Chemistry
University of Helsinki
Helsinki, Finland

Jeffrey S. Gaffney
Argonne National Laboratory
Argonne, Illinois, USA

S. Jayarama Reddy
Department of Chemistry
Sri Venkateswara University
Tirupati, India

Nacho Martı´n Garcı´a
Universita de Valencia
Departamento de Ingenieria Quı´mica
Valencia, Spain

Roger Jeannot
BRGM Laboratory of Enviornmental
Chemistry
Orleans, France

Carmen Garcı´a-Jares
Departamento de Quı´mica Analı´tica,
Nutricio´n y Bromatologı´a
Facultad de Quı´mica
Instituto de Investigacio´n y
Ana´lisis Alimentario
Universidad de Santiago de Compostela
Santiago de Compostela, Spain

Pedro Landı´n
Departamento de Quı´mica Analı´tica,
Nutricio´n y Bromatologia
Facultad de Quı´mica, Instituto de Investigacio´n
y Ana´lisis Alimentario
Universidad de Santiago de Compostela
Santiago de Compostela, Spain

Mohammad Ghafar
High Institute for Environmental
Research
Lattakia, Syria

Riccardo Leardi
Department of Pharmaceutical and
Food Chemistry and Technology
University of Genova
Genova, Italy

Stefania Giannarelli
Department of Chemistry and

Industrial Chemistry
University of Pisa
Pisa, Italy
Marjan De Gieter
Department of Analytical and Environmental
Chemistry (ANCH)
Vrige Universiteit Brussel
Brussels, Belgium
Tadeusz Go´recki
University of Waterloo
Department of Chemistry
Waterloo, Canada
Dimitar Hristozov
Department of Analytical Chemistry
Plovdiv University
Plovdiv, Bulgaria

© 2006 by Taylor & Francis Group, LLC

Martine Leermakers
Department of Analytical and
Environmental Chemistry (ANCH)
Vrije Universiteit Brussel
Brussels, Belgium
Congqiang Liu
State Key Laboratory of Environmental
Geochemistry
Chinese Academy of Sciences
Guiyang, China
Maria Llompart

Departamento de Quı´mica Analı´tica,
Nutricio´n y Bromatologı´a
Facultad de Quı´mica, Instituto de Investigacio´n
y Ana´lisis Alimentario
Universidad de Santiago de Compostela
Santiago de Compostela, Spain


www.pdfgrip.com
Contributors

Jau-Jang Lu
Department of Living Science
Tainan Woman’s University
Tainan, Taiwan
Michela Maione
University of Urbino
Institute of Chemical Sciences
Urbino, Italy
Filippo Mangani
University of Urbino
Institute of Chemical Sciences
Urbino, Italy
Nancy A. Marley
Argonne National Laboratory
Argonne, Illinois, USA
Audrey E. McGowin
Wright State University
Dayton, Ohio, USA
Paal Molander

National Institute of Occupational Health
Oslo, Norway;
Department of Chemistry
University of Oslo
Oslo, Norway
Munro R. Mortimer
Queensland Environmental
Protection Agency
Indooroopilly, Australia
Jochen F. Muăller
National Research Centre for Environmental
Toxicology
Coopers Plains, Australia
Manuela Nazzari
Dipartimento di Chimica
Universita` La Sapienza
Roma, Italy
Pavel Nesterenko
Department of Analytical Chemistry
Moscow State University
Moscow, Russian Federation

© 2006 by Taylor & Francis Group, LLC

xix

Leo M.L. Nollet
Hogeschool Gent
Department of Engineering Sciences
Ghent, Belgium

Declan Page
Power and Water Corporation
Darwin, Northern Territory, Australia
Brett Paull
National Centre for Sensor Research
School of Chemical Sciences
Dublin City University
Dublin, Ireland
Sigrid Peldszus
NSERC Chair in Water Treatment
Department of Civil Engineering
University of Waterloo
Waterloo, Ontario, Canada
Ana Marı´a Afonso Perera
Departamento De Quı´mica Analı´tica,
Nutricio´n y Bromatologı´a
Facultad de Quı´mica
Universidad de La Laguna
Avda. Astrofı´sico Francisco Sa´nchez
Tenerife, Spain
Anna Pielesz
Textile Institute
University of Bielsko-Bial⁄a
Bielsko-Bial⁄a, Poland
Peter Popp
Centre for Environmental Research
Leipzig-Halle
Department of Analytical Chemistry
Leipzig, Germany
Soledad Prats

Department of Analytical Chemistry,
Nutrition and Bromatology
University of Alicante
Alicante, Spain
Iva´n P. Roma´n
Department of Analytical Chemistry,
Nutrition and Bromatology
University of Alicante
Alicante, Spain


www.pdfgrip.com
xx

Antoine-Michel Siouffi
Universite´ de Droit
Ave Escadrille Normandie
Normandy, France
Bjoern Thiele
Institute for Chemistry and Dynamics of
the Geosphere
Institute III: Phytosphere
Research Centre Juălich
Juălich, Germany
Evaristo Ballesteros Tribaldo
University of Jae´n
Jae´n, Spain
Zhendi Wang
Emergencies Science and Technology Division
Environmental Technology Centre

Environment Canada
Ottawa, Ontario, Canada

© 2006 by Taylor & Francis Group, LLC

Contributors

Isabelle Windal
Department of Analytical and Environmental
Chemistry (ANCH)
Vrije Universiteit Brussel
Brussels, Belgium
Fengchang Wu
State Key Laboratory of Environmental
Geochemistry
Chinese Academy of Sciences
Guiyang, China
Guang-Guo Ying
CSIRO Land and Water
Adelaide Laboratory
Glen Osmond, Australia


www.pdfgrip.com

1

The Sampling Process
Munro R. Mortimer and Jochen F. Muăller

CONTENTS
I.
II.
III.
IV.
V.
VI.

Introduction ........................................................................................................................ 2
The Nature of the Environment and the Complexity of the Sampling Task ................... 2
The Complexity of the Sampling Process and the Need for Clear Objectives ................ 2
Representativeness in Environmental Sampling ............................................................... 3
The Role of Time in Environmental Sampling ................................................................. 3
Design and Implementation of a Sampling Program ........................................................ 4
A. Spatial Boundaries for the Study ............................................................................... 4
B. Scale of the Study ...................................................................................................... 4
C. Timing and Duration of Sampling Effort .................................................................. 5
D. Potential Sources of Variability in Data Collected ................................................... 6
VII. The Need for a Proper Statistical Design for Sampling ................................................... 6
A. Simple Random Sampling ......................................................................................... 7
B. Stratified Random Sampling ...................................................................................... 7
C. Systematic Sampling .................................................................................................. 8
VIII. Sampling Specific Matrices ............................................................................................... 9
A. Sampling Soil ............................................................................................................. 9
B. Sampling Waters ........................................................................................................ 9
C. Integrating Samplers ................................................................................................ 11
D. Sampling Groundwater ............................................................................................ 11
E. Sampling Precipitation (Rainfall, Ice, and Snow) ................................................... 12
F. Sampling Bottom Sediments ................................................................................... 12
G. Sampling Suspended Particulate Matter .................................................................. 14

H. Sampling Air ............................................................................................................ 15
I. Sampling Biota ......................................................................................................... 17
J. Use of Biota as Environmental Samplers ................................................................ 18
IX. Time Integrated Monitoring of Pollutants Using Abiotic Passive Sampling Devices ... 19
X. QA and QC in Environmental Sampling ......................................................................... 20
A. The Need for Documented Environmental Sampling Protocols ............................. 20
B. QA of Data ............................................................................................................... 23
C. Chain-of-Custody Record ........................................................................................ 24
D. QA of Sample Integrity ........................................................................................... 24
E. Use of Blanks ........................................................................................................... 24
F. QCs for Representativeness of Sampling ................................................................ 25
G. Recording Locations of Sampling Sites .................................................................. 25
H. Sample Containers ................................................................................................... 25
I. Sample Preservation/Stabilization and Storage ....................................................... 26
J. QC Samples .............................................................................................................. 27
XI. Health and Safety of Sampling Personnel ....................................................................... 28
XII. Summary and Checklist ................................................................................................... 28
References ..................................................................................................................................... 29
1

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
2

Chromatographic Analysis of the Environment

I. INTRODUCTION
Any study is only as good as its weakest component. Accordingly, the quality of the output from an

environmental sampling project is limited by whichever is the weakest component — sampling or
analysis. The last 40 years have seen incredible improvements in analytical chemical techniques
and precision.1 However, the basic process of sampling the environment to acquire material for
analysis has received comparatively little attention. Consequently, shortcomings in sampling
aspects of environmental assessment often limit achievement of the data requirements. Moreover,
how well the analyzed samples represent the target environment is unknown or at best uncertain.
In this chapter we provide an overview of essential steps in designing, organizing, and carrying
out a successful program of environmental sampling, in which the requirements of adequate
sampling are considered. We examine each of the basic considerations:
– the nature of the environment,
– the complexity of the sampling process including the range of media which can be
sampled,
– the causes of variation in the material which can be sampled and how such variations
can be addressed in sampling design,
– the spectrum of sampling methodologies applicable to sampling different media under a
varied range of circumstances,
– important considerations related to “quality assurance (QA) and quality control (QC)”
in the environmental sampling context.
It is not possible to cover each of the relevant topics in detail in a single chapter, but we have
highlighted the issues to be addressed in planning and executing an environmental sampling
project. For a more detailed coverage of individual topics, the reader should consult dedicated
publications, for example, Ref. 2, and also take note of the relevant requirements of
any environmental regulatory agencies with regard to data from the study being undertaken.

II. THE NATURE OF THE ENVIRONMENT AND THE COMPLEXITY OF THE
SAMPLING TASK
Collecting truly representative samples from the natural environment is no simple task. The natural
environment is both complex and heterogeneous, comprising a multitude of matrices (air, water, soil,
sediment, biota), each with associated difficulties and potential sampling approaches. The concentrations of contaminants are usually nonuniform in space and over time and this adds to the complexities
in sampling. In addition, the boundaries of the environment being sampled may not be sharply defined

or indeed visible; the material sampled will rarely, if ever, be strictly uniform, and in many cases
the properties of interest, for example, trace concentrations of contaminants, can be lost or at least
altered in the sampling process through reactions with other components of the sample or with the
materials used to collect and store the samples. All too often, conclusions based on laboratory results
from the most careful analysis of the chemical and other properties of environmental samples are
invalidated because the original collection of the environmental samples was inadequate or invalid.

III. THE COMPLEXITY OF THE SAMPLING PROCESS AND THE NEED FOR
CLEAR OBJECTIVES
The planning of any study involving environmental sampling should begin with the determination
of unambiguous sampling objectives defined by the data requirements of the study. These should be
clearly stated at the outset.

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
The Sampling Process

3

At the core of any environmental sampling project are a series of questions relating to the
purpose of sampling:
–
–
–
–

What are the purposes or goals of the program or study being undertaken?
What are the underlying questions to which answers are sought?

What information is relevant, and over what spatial and temporal scales?
How will the data be evaluated and presented?

Subsidiary questions include
–
–
–
–
–

Where and when should the samples be collected?
How many samples are needed?
What matrices should be sampled and what equipment is appropriate?
How will the samples be preserved and what containers should be used?
What QC procedures and QA criteria and thresholds are required for the sampling
process (as distinct from and additional to, QC/QA for laboratory analyses)?

Unless these questions are asked and answers are determined without ambiguity, before the
collection of any environmental samples, there can be little confidence that the data derived
from the analysis of the environmental samples, regardless of the precision and accuracy of the
laboratory tasks, can provide useful or reliable insights as to the true state of the environment
sampled.

IV. REPRESENTATIVENESS IN ENVIRONMENTAL SAMPLING
A environmental sample can be called representative, when it is collected and handled in a manner
which preserves its original physical form and chemical composition. Accordingly, in the statistical
sense, representative samples are an unbiased subset of the population measured.
To retain valid representativeness after collection, samples must be handled and preserved
using methods adequate for preventing changes in the concentration of materials to be analyzed, by
loss or by introduction of outside contamination. Failure to take account of each of the factors

which can potentially reduce the representativeness of samples for the target environment is likely
to result in analyzing samples which are not truly representative.
Analysis of samples which are not representative of the environment being assessed is
inevitably a wasted effort and may lead to wrong and even expensive conclusions. The data from
analyses may be precise and accurate in relation to contaminants of interest in the samples, but if the
samples are not intrinsically representative of the environment, then the data has little relevance to
the location or sites in question.

V. THE ROLE OF TIME IN ENVIRONMENTAL SAMPLING
The composition of the matrix to be sampled can often vary with time. If the rate of change is
significant relative to the time needed to collect the sample, this alone makes meaningful
interpretation difficult. The sampling of flowing water and gases frequently presents these kinds of
challenges. Resolution of such sampling difficulties usually requires careful consideration of the
use to which the data will be put. For example, if the measurements being made are for the purpose
of assessing average exposures or loadings of contaminants, numerous samples can be taken over a
long period of time and pooled prior to analysis to form a composite sample. However, if the release
pattern of contaminants, and concentrations to which sensitive organisms are exposed is required,
forming composites would not be appropriate. Instead the capture and analysis of many discrete

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
4

Chromatographic Analysis of the Environment

samples, each taken over a short time interval may be more relevant. For some constituents of
flowing material, continuous sampling using appropriate sensors and instrumentation may be
appropriate.

VI. DESIGN AND IMPLEMENTATION OF A SAMPLING PROGRAM
To be successful, a sampling program must address and meet its objectives. There are a series of
basic requirements in design and implementation to achieve that success. The American Chemical
Society Committee on Environmental Improvement3 suggests the following minimum requirements for an adequate sampling program:
a proper statistical design which takes into account the goals of the study and its
certainties and uncertainties;
† documentation of protocols for sample collection, labeling, preservation, and transport
to the analytical facility. Such sampling protocols are “expressions of professional
accountability” all too frequently lacking in environmental studies4;
† adequate training of personnel in the sampling techniques and procedures specified.

†

However, even before these essential elements can be addressed, there are number of
preliminary but equally important issues to be considered:
the spatial boundaries of the sampling program should be defined;
the scale of the sampling program should be defined;
† the timing and duration of the sampling program should be defined;
† potential sources of variability in data collected should be identified;
†
†

The flow diagram (Figure 1.1) shows the essential components of a well-designed
environmental sampling project, each of which needs to be addressed from the preliminary
planning stages through to the implementation of the sampling project.

A. SPATIAL B OUNDARIES FOR THE S TUDY
The setting of boundaries should be based on the issues of concern giving rise to the need to conduct
the sampling program, rather than on convenience or budgets. If boundaries are set inappropriately,

significant and relevant sources of contamination and impact may be missed. For example, if the
sampling is a component of a catchment study, the spatial boundaries for the sampling program
should be those of the catchment of focus, or a series of sampling programs designed on a
subcatchment by subcatchment basis.

B. SCALE OF THE S TUDY
The scale of a study depends on the spatial and temporal ranges within which in situ measurements
and samples for laboratory analysis will be taken. The appropriate scale is determined by
consideration of the scale of the process or processes underlying the questions being addressed by
sampling. For example, the rate of movement of contaminants in soils is slow relative to transport in
flowing waters, so that the spatial scale appropriate for sampling downstream of a source of
contamination will vary depending on the nature of the receiving environment.
An effect such as bioaccumulation in organisms exposed to contaminants is influenced by
duration of exposure. This gives a temporal aspect to decisions concerning an appropriate scale of
sampling.

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
The Sampling Process

5

Consider data objectives

Consider
QA/QC
needs

Define objectives and
accuracy required

Consider
OH&S issues

Consider
QA/QC
needs

Select sample collection
methods

Consider
OH&S issues

Choose
analytical
methods,
sampling
volume

Define
locations of
sampling

Determine
sample
preservation
and storage

requirements

Define time
and frequency
of sampling

Determine
sample
container
requirements

Define sample stabilisation
and transport

Define analytical
procedures

Interpretation on the basis
of
– assessed accuracy
– sampling design

FIGURE 1.1 Flow chart of an environmental sampling project.

C. TIMING AND D URATION OF S AMPLING E FFORT
Timing and duration of sampling effort can be critical supplementary considerations in relation to
the scale of sampling which is appropriate. This is particularly important when sampling involves
collecting data from a system which is inherently variable in its capacity to transport
contaminants. A flowing stream is a good example of a system with a variable transport capacity.
For sampling in such a system, rainfall and stream flow patterns need to be taken into account, in

terms of their potential effects both on the transport and on dilution of materials of interest for
sampling. Sediment loads in streams, the base load and suspended material, are usually very
different between storm run-off peaks and times of low flow. Contaminants washed out of a
catchment by storm events often exhibit a “first-flush” concentration peak which may be of short
duration relative to the overall period of high flow. Sampling of first-flush events requires a
specific approach different from that of sampling a stream during normal flow conditions, but
more importantly, data collected during such different flow conditions will, for most measurable
variables, be quite different.

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
6

Chromatographic Analysis of the Environment

D. POTENTIAL S OURCES OF VARIABILITY IN DATA C OLLECTED
Before a sampling program is commenced, all of the potential sources of variability of the data
should be considered and minimized by prudent planning. For example, some potential sources of
variability arise from sample handling and storage. These are discussed later in this chapter under
the respective headings. However, actual environmental heterogeneity in respect of whatever
variable is being measured, either in situ or in samples of actual materials, will be encountered,
because that is the nature of the real environment. In addition, variability is potentially increased by
seasonal and other time-related effects, disruptive processes such as soil disturbance, changes to
drainage patterns, and patterns of chemical dispersion.
While a field sampling program is still at the planning stage, all potential sources of spatial and
temporal variability should be assessed from sources such as published reports from similar sampling
programs, and from consideration of the nature of the system to be sampled. For example, in planning
sampling of soils, the type of soils to be encountered and attributes such as the particulate structure

(which is likely to influence the distribution of metallic contaminants) and the presence of organic
matter within the soil matrix, and often a surface layer of dead plant matter, should be considered.
Organic matter usually accumulates organic chemical contaminants, so the question of whether a
surface layer should be included with the soil sample, or scraped off before sampling the underlying
soil, or taken as a discrete sample of material in addition to a companion sample of the underlying soil
(to a prescribed depth), needs to be addressed at the planning stage. Similarly, in taking water samples
from a waterbody which is unlikely to be well-mixed due to influences such as thermal stratification
in a deep lake, the depth(s) from which samples are taken needs to be considered. Temporal
contributions to variability can arise from diurnal and seasonal effects on water chemistry such as
temperature and dissolved oxygen concentrations (particularly if algae are present in high numbers),
as well as from the effects of flow variation and stormwater first-flush influences.
If all of the potential factors affecting variability are not considered and the sampling approach
is not adapted to minimize each factor as much as practical, the resulting data set may prove to be so
variable that impacts, disturbances and trends are totally obscured. If there is insufficient previous
knowledge, the nature of the environment and media at the locations to be sampled, and, in
particular, if the factors contributing to environmental heterogeneity are uncertain, a pilot study, or
at least an on-the-ground inspection and assessment, should be done. Such assessment should
involve testing of possible sampling approaches, and the taking of “typical samples” for assessment
of factors which are likely to contribute to high variability is strongly recommended.

VII. THE NEED FOR A PROPER STATISTICAL DESIGN FOR SAMPLING
In practical terms, only small portions (samples) can be taken from an environment under
assessment. Accordingly, the samples need to be representative of the media and the environment
that is the focus of the study, within practical limitations determined by the resources available to
those charged with the assessment task.
This requires a proper statistical design for sampling. The aim of the statistical design is to
ensure the sampling effort maximizes every opportunity to be representative of the environment
being sampled and minimizes errors. Statistical designs for sampling can be based on a number of
different approaches, each based on the concept of randomness, i.e., every sample unit available in
the population (the environment being sampled, as defined according to scale, spatial, and temporal

boundaries defined in the sampling program) must have an equal probability of being included in
the set of samples taken for assessment. There are three basic statistical designs available:
simple random sampling;
stratified random sampling; and
† systematic sampling.
†

†

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
The Sampling Process

7

A. SIMPLE R ANDOM S AMPLING
The totality of available sampling units within the environment in terms of its spatial and temporal
extent is sampled without conscious or unconscious selection or rejection of particular units. It
should be noted that random sampling is not the same as “haphazard sampling.” For example,
random sampling may involve the use of a random number table or computer-generated set of
random numbers to select sampling sites from within all possible coordinates defining a locality.
However, procedures such as sticking a pin into a map while blindfolded are often subject to
unconscious bias, resulting in a set of samples which provide a biased assessment of the
environment being sampled.
Methods of assigning sampling locations without bias are discussed in standard statistical texts.
Typically, all possible sampling locations within the spatial boundaries of the study location are
defined using a grid system of coordinates superimposed on a large scale map or aerial photograph.
Subsequently, actual sampling locations are chosen using a computer-generated series from all

possible coordinates falling within the spatial boundaries, or by using a random number table. More
often than not, box (square) grids are used to cover the area defined by the spatial boundaries for
terrestrial sampling, but triangular or other shaped patterns are equally valid. Where contamination
patterns relative to a point source are being assessed by sampling, it is often useful to construct a
sampling grid as a series of rays projected outwards from the source. Sampling of water from lakes
or embayments can be systematized by constructing a grid of transect lines (Figure 1.2). Similarly,
the times for taking samples from a time-varying system can be randomized to avoid bias using a
method which ensures that all possible sampling times have equal opportunity to be included.
Simple random sampling may not be the most cost-effective sampling design, for example, if
there is prior knowledge of a particular spatial distribution pattern for the contaminants of interest.
Similarly, if there is prior knowledge of temporal influences or media transport influences such as
wind or stream flow on the likely concentration distribution for contaminants of interest, a simple
random sampling at all possible times and all possible flow conditions may not be the most costeffective strategy. In such circumstances, other approaches such as those described below can be a
more efficient use of resources.

B. STRATIFIED R ANDOM S AMPLING
In stratified random sampling, the system to be sampled is divided into a number of parts (strata)
within each of which the contaminant concentration or other descriptor of interest is likely to be
relatively consistent. Such strata need not be of equal size and the numbers of sampling units taken
within each stratum can be set according to the anticipated degree of variability of whatever is being
measured within that stratum. For example, in a stratum where variability encountered is expected
to be relatively low, a small number of sampling units could prove adequate, whereas in another
stratum with inherently high variability, a larger number of sampling units may be required.
Strata may be spatial, temporal, or determined by other relevant criteria. For example, in the
spatial sense, a series of strata could comprise discrete areas associated with a study location, each
with different geology, or different topography, or different history of contamination, or different
soils (or aquatic sediments), or waters sampled at different depths within a lake to take account of
stratification or, in an estuary, salinity gradient. See Ref. 5 for more detail of stratification issues in
water sampling. In the temporal sense, different strata could comprise different seasons, or portions
of the diurnal cycle, or time periods relative to a process such as an upstream effluent release.

Examples of strata determined by other criteria include sampling of biota for bioaccumulated
contaminant content using species, or size (perhaps size class), or age (perhaps age class), or
determinants such as sex, or reproductive status, or the assignment of specific organs or tissues as
strata for sampling purposes.

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
8

Chromatographic Analysis of the Environment

Parallel line sampling grid for
sampling a shoreline (equal
spacing or unequal spacing)

Transverse line sampling grid
for an irregularly shaped lake

Point source

Ray sampling grid for point
source contamination

FIGURE 1.2 Examples of grids for sampling bottom sediments.

Methods of calculating statistical parameters from stratified sampling data are discussed in
standard statistical texts.

C. SYSTEMATIC S AMPLING
In systematic sampling, sample units are collected at regular intervals in space or time. However, as
is the case in simple random sampling, care is needed to ensure that bias is avoided. For example,
temporal sampling conducted on a regular sampling schedule may coincide with periodicity within
the site or system being assessed and thus risk collecting data which is not representative of
conditions at other times. As an illustration, discharges of effluents are often periodic in nature in
respect of constituent composition and relative concentrations, related to the process schedule
which produces them. Accordingly, a systematic sampling taking samples according to a regular
schedule involving collection at the same time every day would produce quite different data than a
schedule involving collection every hour throughout the day. Similarly, in collecting water samples

© 2006 by Taylor & Francis Group, LLC


www.pdfgrip.com
The Sampling Process

9

from tidal or estuarine waters, the values for variables of interest might depend on the state of the
tide, so that samples taken on an ebb tide would not be representative of conditions during the flood
tide or at slack water. See Ref. 5 for more details of temporal issues in water sampling.

VIII. SAMPLING SPECIFIC MATRICES
A. SAMPLING S OIL
Soils are a complex and usually heterogeneous matrix. Soil profile changes with depth; typically
within the first meter there are marked changes in type, composition, texture, moisture, and organic
matter. In addition, there are usually changes in factors such as porosity and the proportion of
organic matter of plant origin (for example leaf litter) within the first centimeter.
A simple and direct method for taking near-surface soil samples is to use a spade and scoop.

This approach is usually practical only to a depth of about half a meter, after which it becomes too
labor intensive. It is important to use a precleaned spade, preferably with a stainless steel blade if
metal analysis is to be conducted on samples. Similarly, a stainless steel (never chrome-plated)
trowel or spoon should be used to manipulate sample material, for example to transfer it into storage
containers.
The most complete method of sampling soils is to excavate and expose the profile, giving
access to allow sampling of undisturbed material from the side of the excavation. Other common
methods involve the use of augers to extract bore samples, or devices such as split-barrel samplers
and thin-walled tubes which are inserted to take a core sample through the soil profile. However,
adequate penetration of soils containing rock fragments may be difficult with such devices. Thinwalled tubes can be sealed with the undisturbed soil core retained inside and thus serve as sample
containers for storage and transport for laboratory analysis. Soil samples taken from the sides of
holes, auger spoil, and core materials removed on site from coring devices are commonly
segregated according to depth and are sealed in appropriately prepared and labeled jars.
Prior to commencing sampling with a spade, drill, or coring device, the soil surface should be
cleared of surface debris such as rocks, sticks, plant material, and litter including dry grass and leaf
matter. In some circumstances such surface materials may also need to be taken as a sample for the
purposes of the study. It is wise to clear this loose material for a sufficient distance from the point of
excavation of insertion of a drill or coring device to ensure loose surface matter does not fall into the
hole and contaminate subsurface samples.
Free air and gases held within the soil matrix can be sampled using metal tubes fitted with
valves or seals at the upper end suitable for the extraction of a gas sample with a gas-tight syringe.
Such tubes are driven into the soil to the required depth prior to taking of the gas sample.

B. SAMPLING WATERS
With respect to water sampling, common pitfalls in sampling strategy arise from making a false
assumption that a waterbody is well-mixed and homogenous in time and space. This is rarely the
situation even in vigorously flowing and shallow waters, and factors which may cause variability
should be taken into account, along with the purpose for which sampling is being undertaken, when
the sampling program is designed.
A false indication of apparent homogeneity within a waterbody can result from failure to take

true replicates. For example, a series of aliquots taken from a single grab sample such as a bucket
are not replicates from the waterbody being sampled. True replicates are a series of individually
taken grab samples or buckets of water.
Major factors which can result in a lack of homogeneity within a waterbody are temperature
and depth. In deep waters there is often an euphotic zone extending below the surface. Most of the
biological productivity takes place within this relatively shallow layer and its chemistry is often

© 2006 by Taylor & Francis Group, LLC