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Essentials of medical
geology: Impacts of the
natural environment on
public health
Edited by Olle Selinus, Brian
Alloway, José A. Centeno, Robert
B. Finkelman, Ron Fuge, Ulf
Lindh and Pauline Smedley
Elsevier Academic Press, Burlington,
MA, San Diego, CA, USA, and
London, UK, 2005, xiv + 832 pp.,
Hardcover. £59-99. ISBN 0-12-
636341-2.
S250 Science in context,
Science, Level 2, Topic 3:
Water and well-being:
arsenic in Bangladesh
by Steve Drury
The Open University, Milton Keynes,
UK, (purchase via: Open University
Worldwide, Milton Keynes MK7 6AA,
UK or http://www.ouw.co.uk), 2006,
115 pp., Softcover. £18-95. ISBN 0-
7492-1435-X.
Scalding, baking, suffocating or slow poi-
soning—Mother Earth has many ways of
severely affecting your health. Medical geol-
ogy is defined as the science dealing with the
relationship between natural geological fac-
tors and health problems in man and animals.
Ever since the catastrophe at Herculaneum
and Pompeii in 79 AD, it has been obvious
that volcanoes can be bad for human health
but, with the passing of time, the more insid-
ious effects of natural poisoning began to be
recognised. For example, contemporary writ-
ers noted that Roman criminals, used as
slaves to mine cinnabar (a mercury ore) at
Almaden, Spain, had a life-expectancy of
less than three years, by the 16th century,
descriptions of mercury poisoning of miners
began to appear (Paracelsus, 1567; Scopoli,
1761; Parés y Franqués, 1778). In an account
of the numerous diseases to which miners
were prone, Agricola (1556, Book VI),
included dust-induced “asthma” and a dis-
ease afflicting miners in the Carpathian
Mountains which caused premature death
from a “terrible consumption”. Paracelsus
(1567) who, like Agricola, worked as a
physician in the town of Jácymov (Joachim-
sthal) in the Erzgebirge (Ore mountains)
which separate the present-day Czech
Republic from Germany, also reported a high
mortality rate from lung diseases amongst
miners. Radon (
222
Rn) gas, originally known
as “radium emanation”, was discovered by
Friedrich Dorn in 1900 and these latter
accounts have been assumed by modern writ-
ers to refer to the radon-induced lung-cancer
now recognised to have occurred amongst
miners working the uranium-bearing cobalt
and silver mines at Jácymov (Czech Repub-
lic) and the near-by Schneeberg (Germany).
Appleton’s paper in this volume gives an
undated observation (p. 239) that “air escap-
ing from an open uranium mine gallery in the
town of Schneeberg, Germany, contained up
to 10,000 Bq m
-3
radon”. This is of the same
order as measurements made in the 1950s
which recorded ~5,500 to 7,000 Bq m
-3
radon in the mine galleries. As a yardstick,
remediation measures on a domestic
dwelling in the UK would be regarded as
essential if the annual average radon concen-
tration level exceeded 200 Bq m
-3
(p. 258).
A causal connection between the miners’
lung cancer and the presence of radon was
first postulated by Ludewig and Lorenser
(1924), but it was a study by Hueper (1942),
which showed definitively that both non-
occupational factors (e.g. smoking) and
occupational factors other than radon could
be eliminated from consideration, although
complete proof of causation came with quan-
titative studies of radiation carcinogenesis in
the 1950s.
A catalogue of additional adverse
health effects in both man and animals as a
result of either elemental excess or defi-
ciency in soils, water or air, are encountered
in Essentials of Medical Geology, a thick and
sumptuously produced book, printed in
China with 267 illustrations, almost all of
which are in colour, and 178 tables. It is a
pleasure to read, although with an approxi-
mately A4-size page and over 800 pages of
coated paper, it is rather heavy.
Its background lies in an initiative of
the International Union of Geological Sci-
ences, which established an International
Working Group on Medical Geology in 1996
with the aim of increasing awareness of this
topic among scientists, the medical world
and the general public. In 2000, Medical
Geology became Project 454 of the United
Nations Educational, Scientific and Cultural
Organisation’s International Geological Cor-
relation Programme. This led to a number of
short courses on Medical Geology being
offered around the world and these resulted
in the production of this book, first planned
in 1998. Its stated aim “as a reference and as
a general textbook” is to emphasise “the
importance of geology in health and disease
in humans and animals”. What makes it so
interesting is that its authorship ranges from
geochemists to pathologists, epidemiolo-
gists, analytical chemists and toxicologists,
each of whom contribute to different Chap-
ters. The majority (27) of the 59 contributors
come from the USA, plus eleven from the
UK, five each from Canada and Sweden, two
each from Australia, Denmark and Jamaica,
and one each from Germany, Italy, Kenya,
New Zealand, and Taiwan. Following a Pref-
ace by the editors (of whom Olle Selinus of
the Geological Survey of Sweden is Editor-
in-Chief), Chapter 1, (entitled ‘Medical
Geology: Perspectives and Prospects’; 13
pp., 80 references) by B. E. Davies, C. Bow-
man, T. C. Davies and O. Selinus, gives a
brief history of the development of the sub-
ject and serves as a background to the rest of
the volume. Although there are references in
their paper to work by members of the former
Applied Geochemistry Research Group
(AGRG) at Imperial College, London, led by
Professor John Webb, I think it is a pity that
the groundbreaking Wolfson Geochemical
Atlas of England and Wales (Webb et al.,
1978) did not rate a mention (although it is
briefly cited, as authored by an unexplained
“AGRG”, in Chapter 11). Following from
Webb’s early interest in geochemistry and
agricultural problems (Webb 1964, 1971;
Webb et al. 1968), it demonstrated the feasi-
bility of his concept of a regional multi-pur-
pose multi-element geochemical atlas based
on relatively high density drainage sediment
sampling, and set a standard for geochemical
atlases later to be undertaken by geological
surveys in many parts of the world. The rest
of the book’s contents is divided into four
sections: ‘Environmental Biology’, ‘Path-
ways and Exposures’, ‘Environmental Toxi-
cology, Pathology, and Medical Geology’
and ‘Techniques and Tools’.
Episodes, Vol. 30, no. 3
Book Reviews 231
Section 1, introduced by U. Lindh,
comprises Chapters 2 to 8 (183 pp., 23% of
the text). Chapter 2, ‘Natural Distribution
and Abundance of Elements’ (24 pp., 49
refs.), by R.G. Garrett, introduces mineral
chemistry and the biogeochemical cycle,
illustrates the natural distribution of elements
at regional and continental scales, shows
how the distribution of element concentra-
tions can vary in both their central tendancy
and range between similar lithologies of dif-
ferent ages (e.g. molybdenum and cadmium
in different black shale formations of Creta-
ceous age), and discusses the establishment
and interpretation of geochemical
baselines—the natural background (baseline)
concentration level of an element in a stated
target population covering a distinct geologi-
cal or geographical entity. Garrett makes the
point that both sampling medium and analyt-
ical technique need to be taken into account
if a reasonable assessment of bioavailability
is required. Chapter 3, ‘Anthropogenic
Sources’ (17 pp., 33 refs.), by R. Fuge, sum-
marises the many human activities which
have resulted in both localised or more wide-
spread environmental contamination (e.g.
long-range aerial deposition at a regional
scale from industrial plants or the legacy of
world-wide contamination from nuclear
weapons testing and the 1986 Chernobyl
event): mineral extraction and processing;
smelting and refining of metal ores and con-
centrates; power generation from the burning
of fossil fuels, nuclear, geothermal and
hydroelectric power; other industrial and
manufacturing activities; waste disposal
from domestic and industrial sources; agri-
cultural practices; transportation; and the
treatment and transport of water. This is a
most interesting survey and there are cer-
tainly some sources in this section which one
might not immediately think of, such as con-
tamination by fluorine from brick manufac-
ture and arsenic in spent waters from geot-
hermal power production. Chapter 4,
‘Uptake of Elements from a Chemical Point
of View’ (24 pp., 14 refs.), by R. J. P.
Williams, explains the basic chemistry of the
cell and how the chemical composition of the
primitive sea influenced the chemical reac-
tions and elements essential for life. Chapter
5, ‘Uptake of Elements from a Biological
Point of View’ (27 pp., 81 refs), by U. Lindh,
discusses the nature of the essential elements
and the mechanisms for their uptake, and
how those elements not essential, or even
detrimental to an organism, are excluded.
Particular emphasis is placed on the roles of
iron, zinc and copper. Chapter 6, ‘Biological
Functions of the Elements’ (45 pp., 141 refs.)
by U. Lindh, enlarges on the fact that for
each element there is an optimum concentra-
tion range: if its concentration falls below
some minimum value, health effects arising
from deficiency occur, too much and toxicity
will result (e.g. iron-induced anaemia on the
one hand, and the fact that accidental inges-
tion of iron tablets is a frequent cause of fatal
poisoning in children younger than six years
old). The roles of major, minor and trace ele-
ments are examined in detail. Chapter 7,
‘Geological Impacts on Nutrition’ (16 pp., 30
refs), by G. F. Combs jr., again reviews those
elements (calcium, chromium, copper,
iodine, iron, magnesium, manganese, molyb-
denum, phosphorus, potassium, selenium,
sodium, zinc, and the chloride and fluoride
ions) essential for good health and outlines
their dietary sources, mineral bioavailability,
how their concentrations are determined for
clinical assessment in man, and recom-
mended values for dietary intake and opti-
mum concentration ranges in human serum
and plasma, etc. Chapter 8, ‘Biological
Responses of Elements’ (21 pp., 30 refs), by
M. Nordberg and M. G. Cherian, fills in the
picture of element toxicity and deficiency in
man in more detail. Specific metals reviewed
are: aluminium, cobalt, copper, iodine, iron,
manganese, molybdenum, selenium, thal-
lium and zinc; the neurotoxins mercury and
lead; and carcinogens arsenic, cadmium and
chromium.
Section 2, ‘Pathways and Exposures’,
introduced by R. Fuge, comprises Chapters 9
to 20 (323 pp., 41%). Chapter 9, ‘Volcanic
Emissions and Health’ (23 pp., 61 refs.), by
P. Weinstein and A. Cook, is where one dis-
covers that the dangers of volcanic eruption
come from more than the lethal effects of
volcanic “bombs”, molten lava and pyroclas-
tic flows. Not only does fallout of silica- and
zeolite-bearing tephra (“volcanic ash”) cause
severe irritation to eyes, nose, throat, lungs
and exposed skin but it may well lead to later
lung disease, such as silicosis. Toxic and
asphyxiant gases (carbon dioxide, carbon
monoxide, hydrogen sulphide, mercury
vapour, radon, sulphur dioxide and sulphur
trioxide), aerosols (carrying hydrochloric,
hydrofluoric and sulphuric acids), fumes and
smoke may also be emitted during an erup-
tion. As well as causing direct effects to man
and animals in the vicinity, secondary effects
will occur via toxic compounds (including
those of arsenic, cadmium, copper, lead,
mercury, selenium, zinc and fluoride com-
pounds), entering waters, soils and hence the
food chain. The authors produce a compre-
hensive account of all these hazards, and
strategies for monitoring them. Chapter 10,
‘Radon in Air and Water’ (35 pp., 61 refs.),
by J. D. Appleton, notes that, as described in
my introduction, by the 1950s, a conclusive
link between the presence of high concentra-
tions of this naturally occurring radioactive
gas and the occurrence of lung cancer in min-
ers working in uranium mines (particularly in
Europe and Colorado, USA), had been made.
It then began to be recognised that the gas
had a deleterious effect on human health at
much lower concentrations than occurred in
mines and, as a result of migration of the gas
from rocks (particularly uraniferous meta-
morphic rocks, granites and marine black
shales) into waters and soils, it could concen-
trate in houses. The author gives a compre-
hensive account of these factors, how the risk
of radon exceeding a statutory threshold in
dwellings sited in a given region is assessed,
and what remedial action may be taken.
Chapter 11, ‘Arsenic in Groundwater and the
Environment’ (36 pp., 119 refs.) by P. Smed-
ley and D. G. Kinniburgh, begins by review-
ing the presence of this toxic element in min-
erals, rocks, sediments and soils. Although in
some parts of the world there are serious
local problems caused by contamination
from mining, ore-processing and other indus-
trial activity, it is its presence in ground
waters in many parts of the world which
affects, or potentially threatens, the health of
millions of people. The attention of geolo-
gists was probably first drawn to the severe
threat posed by long-term exposure to
arsenic, known in the medical community
since at least the 19th century, by a paper
(not cited by these authors) presented by
Crounse et al. at a symposium “Applied
Environmental Geochemistry” held by the
AGRG, London, in 1983. Crounse et al.
stated that it had long been known in the
medical community that long-term exposure
to arsenic leads to “dose-related develop-
ment of keratoic lesions [horny growths] of
palms and soles followed, after a latent
period of many years, by cancer of the skin”
and that “the same association of cutaneous
keratoses and cancer plus severe peripheral
vascular disease has been demonstrated” in
the 1960s in populations with chronic expo-
sure to arsenic in ground water in Taiwan and
linked to the incidence of lung cancer in
males in Córdoba, central Argentina (see
Crounse et al. 1983 and references therein).
Since that time arsenicosis has also been
recognised as a result of chronic exposure of
populations to arsenic-bearing ground waters
in the alluvial plains and deltas of
Bangladesh and West Bengal (India) which
adjoins Bangladesh, Nepal, northern China,
Vietnam, Hungary and Romania; and in
inland basins in arid and semi-arid areas of
Mexico, Chile and the USA (particularly
California, Navada and Oklahoma). Smedley
and Kinniburgh pay particular attention to
Bangladesh (where at least 14,000 people are
known to be suffering from arsenicosis from
drinking arsenic-contaminated well water
and at least 20 million people may be at risk,
with a further 40 million in the adjacent Ben-
gal basin) and to the possible causative
mechanisms for the problem, as well as dis-
cussing possible remediation techniques.
Unfortunately, the conclusion of this other-
wise useful review that “the detailed mecha-
nisms leading to the release of arsenic to
groundwater are still poorly understood” (p.
294) is erroneous, based as it is on a review
of the literature which inexcusably omits
important papers by Nickson et al. (1998,
2000; 209 and 115 citations respectively,
Google Scholar, July 2006) and McArthur et
al. (2001, 2004; 85 and 17 citations respec-
tively) from the 119 works in the authors’
bibliography. These omitted works suggest
that the arsenic in the groundwater derives
from reductive dissolution of iron oxyhy-
droxide (present, for example, as coatings on
September 2007
232
sedimentary grains) and release of its sorbed
arsenic (which is probably attributable to
Late Pleistocene to Recent weathering of
arsenic-rich base-metal sulphides upstream
in the catchment area) to solution. Micro-
bially-induced reduction of the iron is driven
by the presence of natural organic matter in
peaty strata both within the aquifer sands and
in the overlying confining unit, rather than by
the presence of faecally-derived organic mat-
ter. They have also demonstrated that (i)
arsenic release by oxidation of pyrite and (ii)
competitive exchange with fertiliser phos-
phate both make a negligible contribution to
arsenic pollution. (The case of Bangladesh is
the subject of the second book reviewed
here). Chapter 12, ‘Fluoride in Natural
Waters’ (28 pp., 86 refs.), by M. Edmunds
and P. Smedley, points out that while prob-
lems with human dental caries as a result of
insufficient fluoride intake, requiring supple-
mentation via toothpastes, mouthwashes and
even drinking water supplies (e.g. in parts of
the UK and USA) are relatively well known,
problems with dental and skeletal fluorosis
(the latter, at its worst, leading to deformity)
in man and animals can occur as a result of
anthropogenic activity, such as brick-making
(mentioned above) but excess fluoride con-
centrations naturally occur in ground waters
in the western USA, northern Mexico,
Argentina, North and East Africa, India and
China affecting some 200 million people.
These are mainly associated with areas of
granitic basement rocks, volcanic areas and
geothermal sources, and some sedimentary
basins containing debris derived from
granitic basements, layers of volcanic ash or
phosphatic horizons, etc. Case histories
include examples from India, Northern
Ghana, the United Kingdom, Sri Lanka, East
Africa and Canada. Remediation methods
are also discussed. Chapter 13, ‘Water Hard-
ness and Health Effects’ (14 pp., 64 refs.), by
E. Rubenowitz-Lundin and K. M. Hiscock,
concerns “hard” water, recognisable by diffi-
culty in getting soap to form a good lather
and the presence of “fur” in kettles, which is
commonly encountered in water supplies
drawn from carbonate rocks and reflects the
increase in total calcium and magnesium ions
in the water. Drinking hard water has in the
past been linked with a general reduction in
cardiovascular disease, but more recent stud-
ies suggest that it is the increased magnesium
level which is linked to reduction in death
from acute myocardial infarction (“heart
attack”). Although a number of other studies
have suggested links with some cancers and
eczema, the large number of investigations it
has taken over the last 50 years before clarity
has emerged in the link to heart disease
(largely because of the enormous number of
possible confounding variables which have
to be considered) suggests that a degree of
caution is required in accepting findings
reported in these cases without many more
corroborative results drawn from other parts
of the world. Chapter 14, ‘Bioavailability of
Elements in Soil’ (25 pp., 48 refs.), by B. J.
Alloway, reviews the types and properties of
soils, their chemistry and the uptake of trace
elements by plants—an essential step in the
route between parent rock and ingestion of
elements by man and livestock. Lead and
cadmium are considered in some detail.
Chapter 15, ‘Selenium Deficiency and Toxi-
city in the Environment’ (42 pp., 82 refs.), by
F. Fordyce, notes that this element is an
essential component in an enzyme which
prevents oxidative cell degeneration. Sele-
nium deficiency has been linked to white
muscle disease in animals and is implicated
in heart disorder (Keshan disease), bone and
joint condition (Kasin-Beck disease) and
thyroid-related growth disorders in humans.
Selenium toxicosis, characterised by hair and
hoof loss in cattle, is also recorded from
many parts of the world. Excess selenium
generally occurs in association with coal,
black shales and phosphatic rocks. Case his-
tories from the USA, Italy, China and Aus-
tralia are discussed. Chapter 16, ‘Soils and
Iodine Deficiency’ (16 pp., 60 refs.), by R.
Fuge, notes that iodine deficiency has long
been associated with the occurrence of
endemic goiter (in which the thyroid gland
becomes enlarged in an attempt to become
more efficient), but in infancy (<2 years age)
it can lead to cretinism. Although iodine
itself was not found until 1811, the use of
seaweed in the diet to counteract goitre may
date back to 2700 BC. Iodine deficiency dis-
orders are known from many parts of the
world, particularly South America, Africa
and Asia, but even in the British Isles, goitre
was endemic in parts of Wales, Central and
South-west England and parts of Ireland,
particularly in areas underlain by limestones,
as a result of lack of bioavailability in soils.
Chapter 17, ‘Geophagy and the Involuntary
Ingestion of Soil’ (23 pp., 99 refs.), by P. W.
Abrahams, begins with the observation that
geophagy, the deliberate ingestion of soil, is
common among both birds (there is a
delightful illustration of a macaw eating a
lump of soil held in its claw, reminiscent of a
human eating a cake!) and animals (one
might think of grazing cattle and sheep, but
the practice ranges from rabbits to ele-
phants). Among the human population,
involuntary ingestion by young children may
not be so surprising, but the author docu-
ments a fascinating range of deliberate prac-
tice from around the world, dating back to
prehistoric times but still practiced among
communities in West Africa, Bengal, Central
America, Turkey, etc. as a “medicament,
food detoxifier, psychological comforter, and
a supplier of mineral nutrients”. However,
the practice can lead to toxicity from ele-
ments such as potassium and, in contami-
nated environments, heavy metals. Infection
from ingestion of the eggs or larvae of para-
sitic worms may also occur. Chapter 18,
‘Natural Aerosolic Mineral Dusts and
Human Health’ (21 pp., 14 refs.), by E. Der-
byshire, describes how duststorms often arise
from wind erosion of desert or other arid
regions. They carry with them not only
aerosol-sized mineral particles and, it has
been suggested (Griffin et al., 2002), may
also be a route for bacteria, virus and fungus
transmission. Saharan dustfalls in western
Europe (often noticeable on car windscreens
after rain) are increasing, as are dust storms
in other parts of the world. The occurrence of
silicosis, pulmonary tuberculosis and non-
occupational asbestosis as a result of breath-
ing in aerosol dusts is discussed. Chapter 19,
‘The Ecology of Soil-borne Human
Pathogens’ (30 pp., 40 refs.), by M. W. Bult-
man, F. S. Fisher and D. Pappagianis, relates
to Chapter 17, which mentioned the risk of
parasitic diseases as a result of geophagy.
Here, the full gamut of unpleasant possibili-
ties arising from life forms naturally present
in soils is reviewed: helminths (worms and
flukes), protozoa (giving rise to diarrheal dis-
ease and other infections), fungi (coccid-
ioidomycosis, histoplasmosis, etc.) , bacteria
(anthrax, tetanus, gas gangrene, botulism,
Rocky Mountain spotted fever. etc.) and
viruses (diarrheal disease, polio, Lassa and
hemorrhagic fevers, etc.). The link to geol-
ogy comes with the formation of clay miner-
als during weathering of the parent rock. The
type and abundance of these governs the soil
water potential, soil aggregation and pore
size and hence the movement and types of
pathogens present in the soil. Chapter 20,
‘Animals and Medical Geology’ (13 pp., 24
refs.), by B. Jones, introduces the subject and
discusses the differences between species
and breeds with an emphasis on domesti-
cated animals, particularly cattle, sheep and
swine. Specific elements reviewed are alu-
minium, arsenic, calcium, cobalt, copper, flu-
orine, iodine, manganese, molybdenum,
phosphorus, selenium and zinc.
Section 3, ‘Environmental Toxicology,
Pathology, and Medical Geology’, intro-
duced by J. A. Centeno, comprises Chapters
21–25 (101 pp., 13%). Chapter 21, ‘Environ-
mental Epidemiology’ (11 pp., 6 refs.) by J.
B. Nielsen and T.K. Jensen, reviews the
study of associations between environmental
exposures and the occurrence of disease
within a human or animal population. This
linkage should be solidly founded on statisti-
cal evidence rather than simply an inferential
conclusion, and there are too many studies in
the geological/geochemical literature which
have taken the latter route, probably because
many researchers with a geological back-
ground do not have an adequate grounding in
statistics. The paper explains the differences
between ecological, cross-sectional, case-
control and cohort studies, the advantages
and limitations of each, and the problems
caused by confounding, i. e. the mixing of
effects, where there can be an exposure to
something other than the cause investigated
which is associated with the outcome, but
which may be unequally distributed among
the groups compared. In the example of
radon-induced lung cancer, mentioned in my
introduction and in Chapter 10, in order to
provide conclusive proof of cause, much
careful work was necessary to eliminate the
Episodes, Vol. 30, no. 3
233
effects of smoking and other possible
causative mechanisms. The authors give a
cautionary note against the unthinking use of
a 95% significance level (commonly used in
geological work) for epidemiological
hypothesis testing, suggesting that in this
case a 99.9% level is more appropriate. This
paper should be essential reading for all
supervisors of environmental geology/geo-
chemistry projects which include an element
of epidemiology, as an object lesson in how
such investigations should be carried out,
and also by supervisors and examiners of
research students and by journal referees for
the “Checklist for evaluating an epidemio-
logical paper”, which the authors thought-
fully provide. Chapter 22, ‘Environmental
Medicine’ (21 pp., 48 refs.), by J. Fowles, P.
Weinstein and C.-H. Tseng, is the study of
how the environment affects health. Mecha-
nisms of exposure, dose-response relation-
ships, methods for determining critical
thresholds of toxicological effects, and
health protection are among the aspects
reviewed. Of particular interest in relation to
Chapter 11 is that exposure to arsenic in
drinking water in Taiwan forms the principal
case study. Chapter 23, ‘Environmental
Pathology’ (31 pp., 215 refs.), by J.A. Cen-
teno, F.G. Mullick, K.G. Ishak, T.J. Franks,
A.P. Burke, M.N. Koss, D.P. Perl, P.B.
Tchounwou and J. P. Pestaner, describes the
effects of exposure to toxic trace metals by
means of absorption through the skin, inges-
tion and inhalation. Examples discussed
include: arsenic-induced cancer of the skin;
the effects of lead, mercury, manganese and
tin on the brain; diseases related to inhalation
of asbestos; the effects of selenium defi-
ciency and cobalt, copper, iron, lead, magne-
sium and mercury toxicity on the cardiovas-
cular system and copper and iron toxicity on
the liver. Chapter 24, ‘Toxicology’ (13 pp.;
astonishingly, no other works are cited), by
T.L. Guidotti, compliments the previous
Chapter by explaining why toxic injury
occurs. Chapter 25, ‘Speciation of Trace Ele-
ments’ (21 pp., 61 refs.), by B. Michalke and
S. Caroli, reviews the many analytical meth-
ods used to determine the quantities in which
a chemical species may be present in the
human body and the methods by which
analysis (requiring accurate determinations
at low concentration levels) is achieved. This
is important as different species may have
quite different properties: e.g., chromium
(III) is essential, whereas chromium (VI) is
highly toxic. This Chapter might have been
better placed following Chapter 29 in the
next section.
Section 4, ‘Techniques and Tools’,
introduced by R.B. Finkelman, comprises
Chapters 26 to 31 (132 pp., 17%). Chapter
26, ‘GIS [Geographical Information Sys-
tems] in Human Health Studies’ (11 pp., 43
refs.), by J.E. Bunnell, A. W. Karlsen, R.B.
Finkelman and T. M. Shields, reviews the
many sources of information which may be
used in conjunction with epidemiological
data to assist with problem solving. Case
studies include the occurrence of tick-born
Lyme disease in the USA and fluorosis in
China. Chapter 27, ‘Investigating Vector-
borne and Zoonotic Diseases with Remote
Sensing and GIS’ (20 pp., 38 refs.), by S. G.
Guptill and C. G. Moore, is concerned with
the occurrence of diseases which have a nat-
ural reservoir in an animal or non-human
species and which can be transferred to
humans by an invertebrate (usually an insect,
tick or snail). Remote sensing can provide a
way of integrating regional information on,
say, diurnal temperature, land cover and
topography, vegetation moistness and abun-
dance, etc. with mapped disease incidence as
a means to obtaining predictive models for
disease occurrence. Chapter 28, ‘Mineralogy
of Bone’ (26 pp., 74 refs.), by H. C. W. Skin-
ner, describes the chemistry and mineralogy
of bone, methods for its examination, and
bone diseases, with particular emphasis on
osteoporosis (loss of bone tissue). Chapter
29, ‘Inorganic and Organic Geochemistry
Techniques’ (28 pp., 29 refs.), by M.
Vutchkov, G. Lalor and S. Macko, is a very
useful survey of the many analytical methods
available to assist investigators and compli-
ments those discussed in Chapter 25. Chapter
30, ‘Histochemical and Microprobe Analysis
in Medical Geology’ (11 pp., 20 refs.) by J.
A. Centeno, T. Todorov, J.P. Pestaner, F.G.
Mullick and W.B. Jonas, discusses the vari-
ous techniques which are used to determine
the nature of particulate materials (e.g. dust
or asbestos fibres) present in body tissue (e.g.
in the gastric system or the lung) or bone.
Chapter 31, ‘Modelling Ground water Flow
and Quality’ (28 pp., 59 refs.) by L.F.
Konikow and P.D. Glynn, is a brief review of
the computational methods used to achieve
quantitative models, obviously of prime
importance in the prediction of spread of a
contaminant from its source, and subsequent
design of remedial methods. Geochemical
modelling and sources of code are also dis-
cussed.
Finally, there follow three Appendices:
A, ‘International Reference Values’ (2 pp.,
12 refs.), by P. Bobrowsky, R. Paulen, B.J.
Alloway and P. Smedley, a compilation of
guideline and regulatory maximum values
(mg L-1) in drinking water for aluminium,
ammonium, antimony, arsenic, boron, bar-
ium, beryllium, cadmium, chromium, cop-
per, fluoride, iodine, iron, lead, manganese,
mercury, molybdenum, nickel, nitrite,
nitrate, selenium, silver, thallium, uranium,
vanadium and zinc, (based on information
from Australia, Canada, Japan, the European
Commission, the United States Environmen-
tal Protection Agency and the World Health
Organisation published between 1993 and
2004); B, ‘Web Links’ (2 pp., 34 refs.), anno-
tated URLs for useful sites in relation to
Chapters 19 and 26; and C, ‘Glossary’ which
every reader should find helpful for explana-
tion of specialist terms outside their own
field of expertise among its 512 terms. The
final item is a pretty comprehensive Index
(19 pp.) although, rather tiresomely, it does
not necessarily enable one to find where
papers by a given author are cited in the text.
At the end of each Chapter there is a refer-
ence to others containing related material.
Overall, Essentials of Medical Geology
is an extremely impressive volume and
should be essential reading for students and
professionals involved in environmental geo-
science.
However, those wishing to read more
about the problems posed to humans by the
presence of arsenic in groundwater will find
plenty to interest them in Water and well-
being: arsenic in Bangladesh, a superb little
book produced by Steve Drury as part of the
Open University (Milton Keynes, UK)
Course 250, “Science in context”. It begins
with a quotation, attributed to an anonymous
(?Latin) source that “in any civilised society,
the first provision after a system of laws is a
safe and reliable water supply”. Unfortu-
nately, as documented here, the reader learns
how an endeavour to help the people of
Bangladesh through an international aid pro-
gramme to provide improved drinking water
supplies (in order to avoid the prevalence of
water-borne diseases from surface supplies
by provision of water from wells), went trag-
ically wrong. Chapter 1, ‘Introduction: two
tragedies’ (4 pp.), sets the scene with a 19th
century poisoning and the “poisoning on an
unprecedented scale” now unfolding in
Bangladesh. Chapter 2, ‘Chemical elements
and health’ (25 pp.), reviews concepts such
as the dose-response curve, the results of ele-
ment deficiency and toxicity, why particular
elements are poisonous, the biochemistry of
arsenic and the medical results of arsenicosis
(illustrated by epidemiological results from
studies in West Bengal, which adjoins
Bangladesh, and Taiwan). Chapter 3, ‘Geo-
logical processes and groundwater’ (34 pp.),
explains the geological setting in
Bangladesh, with particular reference to
groundwater, the water chemistry, the geog-
raphy of the arsenic contamination and theo-
ries accounting for the occurrence of the
arsenic in the groundwaters. The hypothesis
of reductive dissolution of iron (III) hydrox-
ide by anaerobic, methanogenic bacteria
assocated with peat-rich layers in the sedi-
ment, releasing adsorbed arsenic, is favoured
here. The implications for other deltaic
regions around the world are discussed.
What makes this book of particular interest is
that Chapter 4 concerns ‘Ethical and legal
issues’. It would appear that while the effects
of arsenic poisoning were first recognised in
West Bengal by D. P. Chakraborty in the
early 1980s, his warnings were dismissed as
“panic mongering” and ignored by both the
Bangladesh Government and the scientific
community. The first account, by A. K.
Chakraborty and K. C. Saha, appeared in the
literature in 1987. The Bangladesh Govern-
ment’s programme of tubewell drilling to
provide improved drinking water supplies,
had begun in 1972, and by 1992 thousands of
both shallow and deep wells had been sunk.
It was only in February 1992, that water from
September 2007
234
some 150 shallow and deep wells of the 4000
drilled under a project funded by the Over-
seas Development Agency of the UK Gov-
ernment was sampled, somewhat as an after-
thought, and analysed by the British Geolog-
ical Survey (BGS), partly to see if there
might be high concentrations of aluminium,
iron, manganese, zinc and phosphate, which
might be toxic to fish which rural
Bangladeshis were being encouraged to
farm. It appears that although the subsequent
report contained information on some 31
analytes (including cadmium, chromium and
lead) and noted the presence of methane
seepages (indicative of the presence of peat
at depth) from some wells, no one had
thought to analyse for arsenic. (Ironic, in
view of the fact that at the 1983 London sym-
posium on “Applied Environmental Geo-
chemistry”, mentioned above, specific atten-
tion had been drawn to the severe effects of
arsenic poisoning in humans from well
waters in Taiwan and that a copy of the book
of the proceedings, in which the Crounse et
al. article appears, is in the BGS library.)
Drury notes that although the 1992 BGS
report on the results of the chemical analyses
did not comment explicitly on the whether
the waters were potable or not, a subsequent
1995 BGS report based upon it stated that
“the groundwater of the study area was ‘suit-
able for crop irrigation and domestic usage’”.
It was not until a subsequent geochemical
survey of the waters of some 3500 randomly
sampled tubewells (an estimated 11 million
are now present in Bangladesh) carried out
by Mott MacDonald International, the
Bangladesh Department of Public health
Engineering and the BGS in the late 1990s
that it was realised that about half of wells
<50 m deep contain from 50 µg L
-1
to over
200 µg L
-1
of arsenic (the World Health
Organisation maximum recommended con-
centration is 10 µg L
-1
) and the magnitude of
the impending arsenicosis problem began to
be recognised, in which millions of people
may now be at risk. This Chapter focuses on
the legal arguments which have ensued since
a group of affected villagers tried to sue the
BGS, via its parent organisation, the Natural
Environment Research Council (NERC) in
2002 for damages for their ill-health con-
tracted from drinking arsenic-contaminated
groundwater which they held had been
claimed to be safe in the reporting of the
original geochemical survey. The case was
declared fit to go to trial by jury in 2003, but
in a subsequent appeal by NERC (2004) the
case was dismissed. The full judgements for
these two hearings are summarized in the rest
of this Chapter, and make fascinating read-
ing. Finally, Chapter 5, ‘Managing and miti-
gating the problem’ (7 pp.), discusses mitiga-
tion methods. The book is completed by a
summary of learning outcomes, answers to
questions, comments on activities, and an 8
page index. Aimed at a broad readership who
are not necessarily geoscientists, the text is
very clearly written and well illustrated with
32 figures in colour, plus 6 tables, and con-
tains a number of thought-provoking exer-
cises for the interested reader.
This book should be widely read as a
cautionary tale, and also used as a case-study
on any undergraduate or postgraduate course
concerned with environmental or medical
geology or geochemistry. It was published
before the results of a further appeal to the
Lords of Appeal in the House of Lords by the
appellant against the 2004 decision were
known; the case was dismissed on 5 July
2006, essentially on the grounds that BGS
had no “duty of care” to test for arsenic in
their original survey, and that the absence of
such analysis carried no implications for the
potability of the water supply or otherwise;
see Lords of Appeal (2006) for discussion.
Nevertheless, it is to be hoped that no future
hydrogeochemical survey, in which assess-
ment of the potability of water supply (and
hence future risk to human or animal health)
is a goal, will omit to include arsenic and the
range of other elements potentially toxic to
man or animals, within its remit.
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Prof. Richard J. Howarth
Department of Earth Sciences
University College London
Gower Street
London WC1E 6BT
UNITED KINGDOM
r.howarth@ucl.ac.uk
Episodes, Vol. 30, no. 3
235
Quantitative seismic
interpretation: Applying
rock physics tools to reduce
interpretation risk
By Per Avseth, Tapan Mukerji,
and Gary Mavko
Cambridge University Press, 2005,
376pp. UK, Hardback: $140.00. ISBN:
0521816017.
Seismic data analysis is one of the key tech-
nologies for characterizing reservoirs and
monitoring subsurface pore fluids. While
there have been great advances in 3D seismic
data processing, the quantitative interpreta-
tion of the seismic data for rock properties
still poses many challenges.
This book demonstrates how rock
physics can be applied to predict reservoir
parameters, such as lithologies and pore flu-
ids, from seismically derived attributes, as
well as how the multidisciplinary combina-
tion of rock physics models with seismic
data, sedimentological information, and sto-
chastic techniques can lead to more powerful
results than can be obtained from a single
technique.
The first author of this book, Per
Avseth, is a senior geophysicist at the Norsk
Hydro research center in Bergen, Norway,
who received his M Sc in Applied Petroleum
geosciences from the Norwegian Institute of
Technology, and his Ph D in geophysics
from Stanford University, California.
An integrated methodology and practi-
cal tools for quantitative interpretation,
uncertainty assessment, and the characteriza-
tion of subsurface reservoirs are provided in
this book with well-log and seismic data,
which illustrate the advantages of these new
methodologies, while providing advice about
the limitations of the methods and their tradi-
tional pitfalls.
Five case-studies are described in
detail. A total of 204 figures and 57 colour
plates are provided, while the MATLAB
codes of the case studies and problem sets
can be downloaded from http://publishing.
ca mb ridge.o rg /r esource s/ 05 2181601 7,
together with seismic and well-log data that
will allow readers to gain a hands-on under-
standing of the methodologies. Though the
Press gives no guarantee for the permanence
or accuracy of URLs, the links were still
active at the time of writing this review.
According to the stated objectives for
this book, it is intended to help make the
links between seismic and reservoir proper-
ties more quantitative and based on the
recognition that subjective information can-
play an important role in quantitative inter-
pretation.
The book has seven chapters. Chapter 1
gives a brief introduction to rock physics, the
science aimed at discovering and under-
standing the relations between the seismic
observables, such as the velocity, impedance,
amplitude, and rock properties, including the
lithology, porosity, permeability, pore fluids,
temperature and stress. The concepts of
bounds on elastic properties are introduced,
which can also be used as powerful interpo-
lators when describing depositional and dia-
genetic trends in the velocity–porosity plane.
Fluid substitution and the special role of
shear-wave information, as well as the
effects of pore pressure, are also discussed.
Chapter 2 focuses on the rock physics
link to depositional and diagenetic trends of
sands, shales, and shaly sands. A number of
specialized models that describe the veloc-
ity–porosity behavior of clastics are intro-
duced with some field examples. The links
between depositional facies and rock physics
properties are established to investigate
depth trends in the rock physics of sands and
shales as a function of diagenesis, which are
finally put all together in basin-specific rock
physics templates (RPTs) which can be used
both for well-log and seismic data analysis.
Statistical rock physics is covered in
Chapter 3, in which various statistical classi-
fication techniques are introduced. It is
shown that to combine rock physics models
with modern computational statistics can
help us more than just using statistics or
physics alone. Monte Carlo simulations are
shown to help us quantify uncertainties in
rock physics interpretation of seismic attrib-
utes. The Matlab TM functions for Monte
Carlo simulation and statistical classification
techniques described in this chapter may be
downloaded from the aforementioned web-
site.
Chapter 4 provides a compilation of the
most common techniques used for quantita-
tive seismic interpretation, including the new
contributions made by the authors of this
book. The chapter starts by explaining some
common pitfalls in qualitative seismic inter-
pretation, and how quantitative techniques
can solve important ambiguities, and
improve the detectability of hydrocarbons.
AVO analysis, ranging from wave-propaga-
tion theory, processing and acquisition
effects, and different ways to interpret the
AVO information are overviewed, as well as
various methodologies to extract rock prop-
erties from near and distant impedance inver-
sions. Some pitfalls associated with the vari-
ous techniques, the great potential to obtain
rock and fluid properties, forward seismic
modeling used to quantify subsurface reser-
voir properties and related discussions are
covered in this chapter.
Chapter 5 describes different case stud-
ies where the concepts described in the previ-
ous chapters are used systematically for the
quantitative prediction of lithologies and
pore fluids from seismic data. The cases
include: seismic reservoir mapping from 3D
AVO in a North Sea turbidite system; map-
ping lithofacies and pore-fluid probabilities
in a North Sea reservoir using seismic
impedance inversions and statistical rock
physics; and seismic lithology prediction and
reservoir delineation using statistical AVO in
the Grane field, North Sea, etc. Although the
examples are drawn from siliciclastic deposi-
tional systems, the methods and workflows
can be applied to other problems, such as car-
bonates, gas hydrates, fractured reservoirs,
and shallow hydrologic site characterization.
Though only static reservoir characterization
is discussed, the methods can be extended to
include time-lapse seismic data.
Chapter 6 recommends specific work-
flows for applying the methodologies of
quantitative seismic interpretation at various
stages of reservoir exploration, appraisal,
development and management. Chapter 7
provides problem sets and an extended reser-
voir characterization project based on an
example of a seismic data set and well logs
provided at the website.
This book is intended to introduce fun-
damental rock physics relations, which help
to quantify the geophysical signatures of
rock and fluid properties. Since rock proper-
ties are a consequence of geologic processes,
the authors begin to quantify the seismic sig-
natures of various geologic trends. They also
fully embrace the use of probabilistic and
geostatistical tools, as quantitative means for
managing the uncertainty that inevitably
accompanies all quantitative methods. Quan-
tifying, managing, and understanding the
uncertainties are critical for survival in a
risky environment.
The book is aimed at graduate students,
academics, and industry professionals work-
ing in the areas of petroleum geoscience and
exploration seismology. Each chapter begins
with a quotation that gives clues as to the
content of the whole chapter. For example,
Chapter 1 starts with the famous words from
Albert Einstein, “Make your theory as simple
as possible, but no simpler”. Chapter 5,
which focuses on case studies, begins with an
aphorism from Seneca: “The path of precept
is long, that of example short and effectual”.
On the first page we read The Buddha’s wise
maxim: “Do not believe in anything simply
September 2007
236
because it is found written in your books. But
after observation and analysis, when you find
that anything agrees with reason and is con-
ducive to the good and benefit of one and all,
then accept it and live up to it”.
The book should also interest environ-
mental geophysicists seeking a quantitative
subsurface characterizations from shallow
seismic data. It could be used as a comple-
ment to other works, among which the
authors recommend: —The Rock Physics
Handbook (Mavko et al., 1998), Acoustics of
Porous Media (Bourbi’e et al., 1987), Intro-
duction to the Physics of Rocks (Gu’eguen
and Palciauskas, 1994), 3-D Seismic Inter-
pretation (Bacon et al., 2003), Interpretation
of Three-Dimensional Seismic Data (Brown,
1992), Principles of Sedimentology and
Stratigraphy (Boggs, 1987), Offset-Depen-
dent Reflectivity: Theory and Practice of AVO
Analysis (Castagna and Backus (eds), 1993),
and Global Optimization Methods in Geo-
physical Inversion (Sen and Stoffa, 1995) for
in-depth discussion of rock physics, seismic
and geological interpretations, AVO tech-
niques and inversion methods.
Yong Chen
Member of the Chinese Academy of Science
China Earthquake Administration
63, Fuxing Ave.
Beijing 100036
CHINA
Office phone: 86-10-88015335
Fax: 86-10-68215973
E-mail: yongchen@seis.ac.cn
The great tsunami in the
Sumatra Region,
26 December, 2004
By Geological Society of India
Published by the Geological Society of
India, 2005, Bangaore, India, 144
pages, ISBN: 81-85867-70-4, $75.00.
This book is published as the 64th Memoir of
the Geological Society of India. The mem-
oirs of this Society cover broad topics in
local geology of India—from the problems
and perspectives of the Indian environment
to the late Quaternary geology of India and
sea-level changes. This memoir focuses on
the great tsunami caused by the Mw9.3
Sumatra earthquake of 26th December,
2004, and contains the preliminary results of
the scientific investigations carried out by
various departments and agencies in the
aftermath of the great earthquake and associ-
ated tsunami.
Almost all the results in this book have
been obtained by Indian scientists and engi-
neers. They are summarized in eleven chap-
ters covering the conclusions from seismo-
graphs, ground motion records, GPS and lev-
eling observations, as well as detailed dam-
age investigation.
Chapter 1 gives a brief introduction to
the seismic and geological background of the
great Sumatra earthquake and the follow-up
response and actions taken by various orga-
nizations. The detailed source parameters of
the event are described and discussed in
Chapter 2. The results in this chapter are
obtained from global records as well as the
data from the Indian network, indicating that
the great event was the second largest earth-
quake ever recorded next only to the Chilean
earthquake of 1960. Analysis shows that the
regional seismographs of the main-shock
recorded at broadband stations in India are
complex, which could be gainfully employed
in joint inversion of seismic data from
regional and teleseismic distances, and geo-
detic data.
The tectonics and seismicity of the
Andaman-Sunda Arc region are briefly
described in Chapter 3.
In Chapter 4, the Tsunami impact in
terms of run-up heights and inundation on
the eastern coast of India as ascertained from
field investigations and tidal observations is
described. The run-up heights along the
coasts of Tamil Nadu, Kerala and Andaman-
Nicobar islands varied between 1.5 and 7.0
m. Study shows that small differences in
local run-up and coastal topography resulted
in large differences in tsunami inundation
and associated loss of life and damage to
property.
Preliminary observations based on the
macroseismic surveys are presented in Chap-
ter 5. The surveys suggest an intensity of VII
on the MSK-64 scale in majority of the
islands, while some parts are assigned inten-
sity VIII. The aftershock activities were
observed with a total of eighteen digital seis-
mograph systems. The preliminary results
are given in Chapter 6.
Although near-field strong ground
motion data for the great event are not avail-
able, preliminary analyses based on the
acceleration data generated in
Andaman–Nicobar islands region for the
large magnitude aftershocks is covered in
Chapter 7, while some analyses based on the
acceleration data generated at distances
exceeding 1,500 km for the main shock are
made in Chapter 2.
The engineering aspects of damages in
the Andaman–Nicoba islands and the main-
land are described in detail in Chapter 8.
These investigations have reiterated the
urgent need to ensure that all the design and
construction practices in the islands region
strictly adhere to the guidelines laid down by
the State Government. The concerns raised
by the great event and the consequent
tsunami are listed at the end of this chapter.
Large-scale horizontal and vertical
ground movements were recorded during the
great earthquake. Chapter 9 focuses on the
preliminary results from the geodetic and
GPS investigations carried out in the region,
which suggest that the islands have moved
2–3 metres in a horizontal direction towards
the mainland and have also rotated in an anti-
clock wise direction. GPS and levelling
observations indicate a total subsidence of
about 1.2 metres.
A complete list and details of various
R&D projects supported by the Department
of Science & Technology in the aftermath of
the great Sumatra earthquake and the
Tsunami are provided in Chapter 10 while
Chapter 11 summarizes the whole report.
The publication provides detailed
information to help researchers, planners and
all persons concerned with earthquake and
tsunami risk and mitigation, in India and
elsewhere in the world.
Fuwang Gao
Associate Professor
Institute of Earthquake Science
China Earthquake Administration
63, Fuxing Ave.
Beijing 100036
CHINA
Office phone: 86-10-88015546
Fax: 86-10-88015552
Email: gaofuwang@seis.ac.cn
Episodes, Vol. 30, no. 3
237
