WORKSHOP IN UPPSALA, SWEDEN 

PHOTOS FROM THE MEETING

September 3-9 there was a workshop on Medical Geology in Uppsala, Sweden. The workshop mainly dealt with future activities including newsletters, brochures etc and the book on medical geology. There was also a two day seminar on medical geology with the "Health and the geochemical environment". The conveners of this seminar were Catherine Skinner, Yale university, USA and Tony Berger, Canada. The Seminar  reviewed current understanding and research needs concerning the effects of geochemical cycles on human health, pathways to the human body, and geochemical influences at the bone, soft tissue and cellular levels. The topics of the seminar were:  Sources and External Pathways, Soils and Plants, Surface and ground water, Effects and Internal Pathways, Hard Tissues (Bones and Teeth), The Cellular Level, Soft Tissues, Cancer and Cardio-vascular diseases. 

Notes of the Workshop and seminar

ABSTRACTS of the symposium

 PROGRAMME

MEDICAL GEOLOGY WORKSHOP AND MEETING, Uppsala, Sweden

ABSTRACTS

E-mail: pwa@aber.ac.uk

Geophagy (or geophagia) can be defined as the habit of eating clay or earth, a practice about which there is great deal of misunderstanding. Whilst many people know and accept that geophagy is undertaken by wild and domesticated animals, and that humans can inadvertently ingest soil by for example hand-to–mouth activity, the deliberate consumption of soil by humans appears to be more difficult to comprehend by many. Yet geophagy can still be found relatively easily throughout many societies of the world today. Often the soils originate from specific locations, and have certain qualities (e.g. colour, flavour and plasticity) that make them desirable to the consumer. Both quantitative and qualitative investigations have shown that considerable quantities of soil can be ingested on a daily basis. The reasons why soils are being deliberately consumed can be difficult to establish, but known causative explanations include the use of soil as a famine food and food detoxifier, as a pharmaceutical, and the ingestion of soils for neuropsychiatric and psychological (comforting) reasons. Ironically whilst many people believe that soils are consumed to satisfy a nutritional deficiency, such a physiological explanation for geophagy remains to be confirmed. Nevertheless, soils do have the potential to supply mineral nutrients to the geophagist, and of all the elements investigated it is especially Fe where the ingestion of soil can account for a major proportion of the recommended daily intake. However, whilst ingested soils can potentially provide certain benefits such as nutrients to the consumer, some medical problems are likely if the geophagy is undertaken inappropriately. Such deleterious effects include mineral nutrient deficiency (e.g. hypozincaemia, hypokalaemia and iron deficiency anaemia), toxicity (e.g. of soil contaminants such as dioxin and Pb, hyperkalaemia), geohelminth infection, intestinal blockage and excessive tooth wear. On occasions deaths are reported. In summary, geophagy warrants more considered attention, although there is evidence that the practice is attracting renewed interest within the academic community. This is important since geophagy remains more widespread than most people realise, and ingested soils have important medical implications of which some such as the nutritional remain to be resolved.

The hydrological, chemical and biological processes that determine the chemistry of surface and groundwaters relating to health issues are examined. The starting point is an outline on the nature and vulnerability of surface and groundwater resources and on the hydrological cycle and its relationship to chemical fluxes in the environment. The various aspects of regulation of discharges and water consents are considered in relation to amenity (riverine ecology), health (e.g. bathing water standards) and potable water. Following these outline introductions, water quality and health is examined in terms of contemporary and historical perspectives using the UK as a primary example. Case studies are presented in relation to surface and groundwater acidification, nutrients, agricultural wastes, micro-organics and sewage discharges and reference is given to trace element mobility both for the UK and at a more global level. The methods of modelling environmental systems is outlined and linked to the issues of maintaining and improving the aquatic environment and health in relation to environmental management and legislative controls. The talk concludes with a resume of current knowledge and an outline of research and management shortfalls for understanding and managing environmental systems both in terms of steady state conditions and evolving patterns of urban, industrial and climate change.

Edmunds, W.M., and Smedley, P.L., 1996. Groundwater geochemistry and health: an overview. In: Environmental geochemistry and health (Eds. Appleton, J.D., Fuge, R., and McCall, G.J.H.). Geol. Soc. (London) Special Pub. 113, 91-105.

Neal, C., House, W.A., Leeks, G.J.L., Whitton, B.A., and Williams, R.J., 2000. Conclusions to the special issue of Science of the Total Environment concerning "The water quality of UK Rivers entering the North Sea". Sci. Tot. Environ., 251/252, 559-576.

R. Naidu and P.R. Nadebaum

During the past 10 years increasing incidences have been reported where the concentrations of constituents associated with the natural mineralisation of soils and sub strata are at levels which can cause adverse effects on human health and the environment. Such pollutants are defined as geogenic contaminants and can include for example selenium, arsenic, fluoride and radionuclides. Significant adverse impacts of geogenic contaminants on environmental and human health have been recorded in USA, Canada, Bangladesh, West Bengal, India and China.

The focus of this paper is on the source, release and transfer of arsenic (As) and selenium (Se) from native mineral species, to plants and human via water and soil with particular reference to incidences of health effects recorded in the Indian subcontinent.

Problems associated with arsenic contamination of groundwater and its adverse effect on human health were periodically reported in the West Bengal newspapers in India and Bangladesh during early 1970’s to late 1980’s. However, limited attention was paid to such reports by the respective governments until mid 1990’s when tubewell water surveys revealed As-contamination of ground water in over 560 villages, where millions of people were directly dependent on tube well water for both potable purposes and for cultivation. It is now believed that as many as 1 million Bangladeshis and Indians have As related diseases, and potentially over 30 million people may be exposed to levels of As which exceed internationally accepted guideline values. Clearly the many incidences of As poisoning recorded in West Bengal India and Bangladesh are related to ingestion of As associated with groundwater; although the pathways of ingestion are not clear. The focus of work by local and international scientists in the Indian subcontinent is on the treatment of contaminated groundwater, on the basis that consumption of contaminated groundwater is the major exposure pathway.

While it is essential to remove direct consumption of contaminated groundwater as an exposure pathway, it is also important to know whether there are other exposure routes which can be important once the water consumption route is removed. Such routes can include incidental ingestion of As contaminated soil, and ingestion of As through crops which have been grown on contaminated soil. Soil contamination can occur through the long term irrigation of land with As contaminated water, with it being possible for concentrations of As in the surface soil to exceed 1000 mg kg^-1. Recent preliminary assessment of samples from a vegetable market in the Chandipur district of Bangladesh identified concentrations of As ranging from 0.1 to 2 mg kg^-1. These concentrations can exceed the permissible levels for food crops (eg 0.05 mg kg^-1 in Australia). Of the 20 vegetables sampled only water convolvulus showed a high level of As uptake, and possible causes of the high As levels observed in vegetables are discussed.

In addition, As which has accumulated in soil can be extremely phyto and ecotoxic, and this may reduce As ingestion via crops by limiting the crop production capacity on significantly contaminated soils. Data from preliminary studies reveal that As added through irrigation water can lead to a significant reduction in soil microbial population.

Contrary to As, Se can have both beneficial and toxic effect on plants and human beings. The narrow gap between essential and toxic concentrations of Se makes it important to understand the processes controlling the distribution of this element in the environment. Fodders, grains and vegetables grown on seleniferous soils in India have been shown to accumulate up to 32 times more Se than the upper toxic limit of 5 mg Se kg^-1 diet for animals and human beings, with the Se content of hair, blood and hoof of affected animals was up to 643, 83 and 37 times higher than that of animals in unaffected areas.

In this presentation we provide an overview of:

• the possible sources and mechanisms of the release and migration of As and Se in groundwater and soil;

• the impact of groundwater contamination on soil quality, plants, humans and animals; and

• the importance of careful consideration of the options for minimising exposure to As and Se and application of various possible methods of remediation.

¹Department of Environmental Sciences, University of Plymouth, Plymouth UK

²T.H. Huxley School of Environment, Earth Sciences and Engineering, Imperial College of Science, Technology and Medicine, London, UK

Concentrations of major and trace elements in soils and grass are determined at Shimba Hills National Reserve in Kenya using geochemical mapping techniques. The study investigates the influence of soil and vegetation type on the concentrations of Na, K, Mg, Ca, Mn, P, Co, Cu, Zn, Mo and Ni and Se in soils and grass. The implications are assessed for the nutrition of the sable antelope, of which the Reserve supports the last remaining viable population in Kenya. Low concentrations in surface soils of a number of major and minor elements are attributed to the geochemical nature of the underlying parent materials of sands, sandstone and grits. Within the Reserve, variations in the element status of surface soils are related to the vegetation and soil types. Elevated element concentrations in surface soils in natural forest areas are attributed to the influence of litterfall whilst in grassland areas, soil element status is controlled by soil type and decreases in the order ferralsols > acrisols > arenosols. The general depletion of elements in soils at Shimba Hills is not reflected as fully in grasses in which concentrations of many elements were of similar magnitude to those reported from other Kenyan conservation areas. Burning of grassland areas leads to elevated concentrations of K, P, Co, Cu and Mo in grasses, elevated soil-plant uptake ratios for P and K and elevated soil pH. It is suggested that increased availability of P in soils at elevated soil pH levels contributes to its enhanced uptake into grass. Use of guidelines developed for domestic ruminants indicates that grass at the Reserve is deficient in Na, K, P and Zn and that the Ca:P ratio exceeds the tolerable range. It is suggested that P deficiency is the primary concern for the Sable antelope population at Shimba Hills.

1University of Zambia, Samora Machel School of Veterinary Medicine, POB 32379, Lusaka, Zambia. 2National Veterinary Institute, POB 8156 Dep., N-0033 Oslo, Norway 3Norwegian College of Veterinary Medicine, POB 8146 Dep., N-0033 Oslo, Norway

Abstract:

Kafue river, an important tributary of the Zambezi river originates in a highly exploited area in the Copperbelt region of northern Zambia. Mining and other industrial activities are highly concentrated around this part of the river. Copper and cobalt production is especially important, but other minerals such as lead and zinc and are also produced. As the river meanders downstream, the Kafue basin harbours the largest national park in Zambia. The Kafue National Park is habitate for a rich and varied fauna and flora which, may be effected by pollution in the area. In order to investigate the possibilities impact of the mining activities from the Copperbelt area, selected tissues from hippopotami were collected from the Kafue river at Kafue National Park in the west and Luangwa river in Luangwa National Park in the east. Luangwa river is regarded as an uncontaminated environment. The results revealed that there were no significant differences in element concentrations between the Kafue and Lwangwa rivers. The levels of copper and other essential elements were similar to those seen in domestic and wild ruminants. Judged from this study, the pollution from the mininig activity in the Kafue area has not affected the hippopotami in the Kafue river.The reported levels of essential and toxic elements may serve as reference for future studies focusing on the hippopotami.

Dr. Maxwell Mwase Paraclinical Studies Department School of Veterinary Medicine P.O. Box 32379 Lusaka 10101 Zambia

The incidence of breast and prostate cancer varies markedly between North America, north west Europe and oriental countries such as China and Japan Table 1.

Source: International Agency for Research in Cancer (IARC) (WHO)

Age-standardised mortality rates show a similar pattern extending back to the 1950’s when reliable data were first compiled.

Migration studies show that people from low-risk countries moving to high-risk countries develop the same pattern of the disease as their host community. This evidence together with studies of twins and modern genetic research suggest that only 5-10% of breast and prostate cancers are genetic. Hence environmental or lifestyle factors appear to account for about 90% of such cancers.

This presentation will review the evidence for links between endocrine disrupting chemicals including surfactants, pesticides and pollutants such as dioxins in the environment and breast and prostate cancer risk. Links between other chemicals that are implicated in promoting these types of cancer such as growth factors and hormones in dairy and other animal products, will also be reviewed.

It is recommended that studies be carried out to establish the feasibility of, including endocrine disrupting chemicals, in regional geochemical mapping programmes, especially over areas used for cultivation or animal rearing.

Copper moves easily through the geosphere and the biosphere. In the Upper Peninsula of Michigan, copper motility can be traced from the Precambrian to the present. Flood basalts in a Precambrian rift basin are filled with native copper. This phase of copper deposition is ascribed to hydrothermal fluid flow during the Precambrian. The Nonesuch shale, an organic-rich black shale having degraded algal cells enmeshed with chalcocite [Cu2S], is the remains of a Precambrian lake that later filled the basin. Weathering of the surrounding copper-bearing rocks would have released copper into the lake and therefore into Precambrian aquatic organisms such as algae. The presence of sulfide minerals such as chalcocite and pyrite in the black shale attests to the presence of an anoxic lake bottom, possibly with heterotrophic and autotrophic microbial populations. Petroleum is being expelled from the black shale. It is thought that burial to depths and temperatures (>66C) that generated petroleum took place during the late Paleozoic. At depths below 200 m today, the ground water of the Upper Peninsula is a saline brine; the brine may have been formed at the same time that petroleum was generated. Copper, petroleum, and brine migrated into adjacent porous sediments and rocks.

Mining of the copper in the Nonesuch Shale at White Pine, Mich., opened new voids. Brine that pooled in the mine at 820 m was coated with films of petroleum dripping from the mine ceiling and with floating green copper minerals. SEM study showed that the green films are atacamite and paratacamite [Cu2Cl(OH)3] which surround bacterial rods and filaments. this suggests that modern bacteria participated in the formation of the floating copper minerals. At the land surface where copper-bearing rocks are weathering today, plants such as pines and mosses concentrate copper in needle, stem, and leaf tissues. Most organisms have copper proteins that make it difficult to exclude copper from tissues. Analysis of trees and mosses has been used as a prospecting tool to find new concentrations of copper to mine. Remote sensing is also being used in prospecting and in determination of ecosystem health because copper affects both absorbance and reflectance characteristics of the plants.

Eleanora I. (Norrie) Robbins, PhD U.S. Geological Survey National Center MS 956 Reston, VA 20192 703-648-6527 (wk) 703-648-6419 (fax) nrobbins@usgs.gov

Described for the first time as a medical entity in the late 1950s, Balkan endemic nephropathy (BEN) is a chronic tubulo-interstitial nephropathy of unknown origin and geographically confined to several rural regions of Romania, Bulgaria and the countries of the former Yugoslavia, located in the alluvial valleys of tributaries of the lower Danube River. Although no one feature is sufficient for disease diagnosis, BEN has several individualizing features that help its diagnosis process and allow differentiation from other tubulo-interstitial nephropathies: the age of onset is usually between 30-50 years, with a slightly higher frequency in women, probably due to some social and genetic factors; a long "incubation" period, at the time of reporting to the physician most patients having end stage renal disease, the only therapeutical solutions left being chronic renal dialysis or kidney transplantation; family history of the disease, with an aggregation of the disease in certain households; normal blood pressure; normochromic and normocytic anemia; at least 10-20 years of residence in one or more of the endemic villages. Along time, many factors have been proposed as etiological agents for BEN (starting from bacteria and viruses to industrial pollution and astrological influences) but in the recent years, based on field and laboratory investigations, an environmental etiology for the disease has become more and more accepted, with a prime role played by the geological background of the endemic settlements. In this regard, there is a growing amount of evidence suggesting the involvement of toxic organic compounds present in the drinking water from the endemic areas. These compounds are supposed to be leached by the groundwater from low rank Pliocene lignite deposits and transported into shallow household wells or springs. The population of the villages from the endemic areas almost exclusively uses well/spring water for drinking and cooking purposes, thus being exposed to the presumably toxic compounds and developing the nephropathy in a time interval from 10 to 30 years or more. An interesting feature of BEN is its frequent association with upper urinary tract (urothelial) tumors, suggesting the action not only of a nephrotoxic, but also carcinogenic, factor.

The Pliocene lignites from the endemic area seem indeed to have a unique organic geochemical composition, with many potentially nephrotoxic/carcinogenic aromatic and nonaromatic molecules, supporting both the hypothesis of the geological etiology of the disease as well as its geographic restriction.

Objectives: To evaluate the relationship between exposure to ground radon levels and leukaemia among children using existing population and disease registers.

Design: Ecological correlation study.

Setting: The county of Östergötland in Sweden.

Methods: Every child born in the county between 1979 and 1992 was mapped to the property centroid co-ordinates by linking addresses in the population and property registers. Population maps were overlaid with radon maps and exposure at birth and each subsequent year was quantified as high, normal, low or unknown. This was analysed with data from the tumour registry. Standardised mortality ratios (SMR) were calculated using the age and sex specific rates for Sweden for the year 1995.

Results: 90 malignancies occurred among 53,146 children (498,887 person years) who formed the study population. SMRs for Acute Lymphatic Leukaemia (ALL) among children born in high, normal and low risk areas were 1.43, 1.17 and 0.25 respectively. The relative risk for the normal risk group and high risk group as compared to the low risk group was 4.64 (95% CI 1.28-28.26) and 5.67 (95% CI 1.05-42.27). The association between ALL and continued residence at normal or high risk areas showed a similar trend. No association between radon risk levels and any other malignancy was seen.

Conclusion: Children born in and staying at areas where the risk from ground radon has been classified as low are less likely to develop ALL than those born in areas classified as normal and high risk.

Keywords : Leukaemia, ALL, cancer, radon, ionising radiation, residential mobility, children, Geographic Information Systems.

(Centre for Quaternary Research, Department of Geography, Royal Holloway, University of London, United Kingdom)

The problem of pneumoconiosis (non-industrial silicosis arises from silica-rich particles of respirable size (< 10 µm, but particularly < 2µm). To what extent loess is the dominant cause of the prevalent respiratory symptoms remains uncertain. The problem extends across High Asia into Ladakh, and has been recognised on the margins of the Thar Desert in northern India.

The Hexi Corridor in North China provides an example of the importance of the environment as a factor affecting the relatively high incidence of pneumoconiosis in Gansu province (with an area the size of France). The Corridor is a natural funnel, down which NW (winter) monsoon winds blow for long periods along this 1200km long transport path. Dust sampling has provided data on pattern, frequency, and volume of atmospheric dust sedimentation in this region. Atmospheric dust concentrations persist here for long periods in all seasons, but there is a recurrent maximum in spring-summer.

Previously unreported (unpublished) studies have shown considerable numbers of subjects with NIS in China’s Gansu Province. In NW China, however, published surveys of silicosis are few in number, although local incidence of pneumoconiosis is known to reach over 20% in older people, and cases of silicosis and silico-tuberculosis in farmers have also been reported in the same province. There thus appears to be emerging some evidence that silicosis is a major public health problem in this extensive region.

The fast-developing field of geomedicine (medical geology), which deals in part with threats to health from natural "silent poisons," could be strengthened by linking with the very active topic of natural hazards. The latter has its own extensive scientific and policy literature and many national and international agencies and programs, but few references to the dangers to health of certain chemical components and reactions in soils, water and air. Since the focus in natural hazards work is almost exclusively on the effects on humans, the introduction of geomedicine, with its extended concerns for animals and vegetation, might also help to balance anthropocentric attitudes towards the environment and, thus, to stress continuities within the biosphere. If, as many contemporary environmental thinkers suggest, a fundamental shift is needed in our attitudes and actions towards the environment and non-human nature, geomedicine may have a signal role to play in re-conceptualising both the beneficial and the harmful sides to the natural world and its processes. On a more practical level, geomedicine might provide guidelines to policy makers and planning authorities in their dealings with places where high or low natural background levels of chemicals in rocks, soils and water can harm human or animal health. A start might be made by developing a simple taxonomy of geomedical hazards, as has been done for geoindicators - geological parameters that can change on decadal times scales or less in ways that are significant for environmental monitoring and assessment. Such a listing would be especially valuable to planners and the general public if it indicated ways to distinguish between environmental chemicals of natural origin and those resulting from human actions such as industrialization, urbanization and waste disposal.

Properly functioning bones and teeth are essential for vertebrates. The focus of attention of orthopaedists and dentists for humans, they are also investigated by anthropologists and biologists for the environmental record they may provide. The growth and development of these distinctive organs and tissues require mineralization by calcium phosphate in the form of apatite, a mineral group that can incorporate many of the elements in the Periodic Table. Studies over many years of the normal and expected evolution of the skeleton, as well as induced and genetic abnormalities, and most recently weightlessness from space travel, have shown that specialized cells and molecules (enzymes and hormones) record local living conditions in the bones and teeth. The chemical and physical attributes of these tissues offer unique opportunities to investigate the uptake and transposition of nutrients or hazardous species encountered in the environment. Knowledge of phosphate biomineralization contributes to our knowledge on the rate of uptake and thresholds necessary for survival and begs questions on the range of bio-available elements including any toxic species. Personal and societal health and well being in the future can be best served by integrating knowledge from the external (geological) and internal (medical) element cycles.

References:

H. Catherine W. Skinner (2000) In praise of phosphates or why vertebrates chose apatite to mineralize their skeletons. International Geological Review 42:232-240.

H. Catherine W. Skinner (1973) Studies in the basic mineralizing system CaO-P₂O₅-H₂O. Calcified Tissue Research 14:3-14.

Albright, J.A. and H.Catherine W. Skinner (1987) Bone: Structural organization and remodeling dynamics. In Albright, J.A. & R. A. Brand, (eds.) The Scientific Basis of Orthopaedics. Norwalk, CT. USA: Appleton and Lange, p.161-198.

Skinner, H. Catherine W. (2000) Minerals and human health. In Vaughan, D.J. & R.A. Wogelius Environmental Mineralogy. European Mineralogical Union Notes in Mineralogy, Vol.2.. Budapest: Eotvos Univ. Press, p.383-412.

Williams, R.J.P & J.J.R. Frausto da Silva (1996) The Natural Selection of the Chemical Elements. Oxford: Clarendon Press.

Robert B. Finkelman, U.S. Geological Survey, Mail Stop 956, Reston, VA 20192, Jose A. Baoshan Zheng, Institute of Geochemistry, Guiyang, P.R. China, 550002 and Jose A. Centeno, Armed Forces Institute of Pathology, Washington, DC, 20306.

In most developed countries coal is used in a way that minimizes direct health impacts. However, in many developing countries, residential use of coal can present serious human health problems because the coals used are generally mined locally with little knowledge of their composition and the coals are commonly burned in poorly vented or unvented stoves directly exposing residents to the emissions. In China alone several hundred million people commonly burn raw coal in unvented stoves that permeate their homes with high levels of toxic metals and organic compounds. At least 3,000 people in Guizhou Province in southwest China are suffering from severe arsenic poisoning due to consumption of chili peppers dried over fires fueled with high-arsenic coal. More than 10 million people in Guizhou Province and surrounding areas suffer from dental and skeletal fluorosis. The excess fluorine is due to eating corn dried over burning briquettes made from high-fluorine coals and high-fluorine clay binders. Inefficient coal combustion can release into the ambient environment large quantities of sulfur, particulates, trace elements (e.g. mercury), and organic compounds such as polycyclic aromatic hydrocarbons (PAHs) that may contribute to respiratory problems. Leaching of the PAHs from lignite aquifers is believed to contribute to a serious kidney problem affecting hundreds of thousand of people in the Balkans. Awareness of the potential environmental and health problems of coal and coal use can be used to prevent these problems or to minimize their impacts.

Metals are important in environmental health and on the study of human diseases

(pathology) because of their potential toxic effect(s) to one or more organs. Exposure to toxic metal ions may occur via three principle routes: percutaneous absorption, ingestion, or inhalation. Dermal toxicity results from local tissue responses through direct contact of the metal with skin, or alternatively, may represent a manifestation of systemic toxicity following ingestion or inhalation. Allergic contact dermatitis induced by nickel (Ni) is an example of a local tissue response. The adverse cutaneous reactions resulting from chronic ingestion or inhalation of arsenical compounds exemplify systemic toxicity.

A variety of toxic pathologic responses in human tissues and organs (i.e., skin, liver, heart, kidney) associated with both acute and chronic exposures to metals have been described.^1-4 The aim of this presentation is to provide examples where both deficiencies of trace elements as well as toxic exposures of metals may be involved in physiologic changes and the development of human diseases. We will discuss the impact(s) of metal ions and trace elements on human health as illustrated with examples of arsenic poisoning from contaminated water in the Bengal Delta (India and Bangladesh) and from coal combustion in southwest China. A brief overview of clinical aspects of toxic metal exposures including discussions of essentiality and clinical manifestations will be presented.

1. Lansdown A. Physiological and toxicological changes in the skin resulting from the action and interaction of metal ions. Crit Rev Tox 1995;25:397-462.
2. Centeno JA, Pestaner JP, Mullick FG, Virmani R. An analytical comparison of cobalt cardiomyopathy and idiopathic dilated cardiomyopathy. Biol Trace Elem Res 1996;55:21-30.
3. Pestaner JP, Ishak KG, Mullick FG, Centeno JA. Ferrous sulfate toxicity: A review of autopsy findings. Biol Trace Elem Res 1999;69:191-198.
4. Centeno JA, Martinez L, Ladich ER, et al. Arsenic Induced Lesions; April 2000: Armed Forces Institute of Pathology publication ISBN: 1-881041-68-9.