SEGH Articles

Putting the Health in SEGH

18 November 2015
Dr Alex Stewart, recently retired from Public Health England, has been an active member of the SEGH International board over many years and a major driving force in bringing the health community together with environmental scientists to promote inter-disciplinary research.

Dr Alex Stewart retired at the end of June as a Consultant in Health Protection for Public Health England, for which his responsibilities included the recognition, characterisation and response to the health effects of environmental issues, including the geochemical components.  Dr Stewart has been involved in SEGH activities for about 20 years, having gained experience and an interest in linking environmental geochemistry and its influence on human health through his interest in iodine deficiency in his years as a GP in the Karakoram mountains of northern Pakistan.

We take the opportunity to ask a few questions of Alex to gain an insight into his extensive experience to the benefit of other scientists at any stage of their career.  In addition, Alex gives us some idea of his plans for the future and his continued engagement with SEGH.

When you started out on your career, what were your fears, hopes, and the reality?  Were there any surprises along the way? 

As a young medical doctor I wanted to work in the wilder parts of the world, but wondered if I was up to it. I was able to join an experienced doctor in starting the General Practice in Baltistan, northern Pakistan, where the health services were thin, stretched and of limited ability. When my colleague retired a few years later, I took over with confidence and developed the work. Perhaps the biggest surprise was my ability to adapt good medical practice in a situation where resources were limited (we ran an outpatient clinic without nearby hospital or laboratory support) and the villagers did not always return quickly for review. It was sometimes hard to know if patients had died, got better or decided my treatments were not worth having! This made learning about what worked and what did not a lot slower but eventually earned me local respect because I was able to ground the medical work in a deep knowledge of the local community.

How were the environmental and health sciences considered early in your career and was there much collaboration between disciplines at the time?

We in health had little understanding of the impact of environmental issues on health, particularly when I was a student and young doctor. Doctors still largely concentrate on the person sitting in our consulting room and ignore wider issues, including, sadly, family and social aspects. The natural environment hardly came into my early understanding of health and disease.

Was there any one event that stood out for yourself personally that influenced your career or the perception of geochemical and health research?

The sharpest event that affected my perception of geochemistry and health was an evening in our house in Baltistan with two passing geologists from Oxford. They were studying the Main Karakoram Thrust, often by binoculars from their jeep in the valley, covering a lot of ground quickly: Baltistan is dry, with very little soil cover on the rocks, so the basic geology can be quite clear in many places. I had become interested in the locally perceived differences in the prevalence of goitre (thyroid swelling in the neck due, in this area, to iodine deficiency) between our side of the river (“1/100”, I was told) and the inhabitants of the villages across the river (“1/10” was the local comment). I had looked and asked about differences between the two sides of the valley and could find nothing that made sense until these passing geologists showed me the Main Karakoram Thrust and indicated its importance as the boundary between Asia (the far side) and the Island Arc north of India (our side). As I began to look into this it was clear that plate tectonics played some part in the distribution of the iodine deficiency disorders across northern Pakistan and perhaps further afield (Stewart AG. Drifting continents and endemic goitre in northern Pakistan. British Medical Journal, 1990; 300: 1507-1512). Following this through led eventually to my appointment as a Consultant in Health Protection with interest in and responsibility for environmental issues (e.g. Mahoney G, Stewart AG, Kennedy N, Whitely B, Turner L, Wilkinson E. Achieving attainable outcomes from good science in an untidy world: Case studies in land and air pollution. Environmental Geochemistry & Health. 2015; 37: 689-706.).

How has your involvement in SEGH helped in your career and enjoyment of your work?

SEGH has been of enormous support, stimulation and help in my career over the past 20-odd years. I first encountered it at a halogen meeting in Kingston-upon-Thames while home on leave in 1994. I went to hear Ron Fuge, the iodine guru from Aberystwyth. Although Ron was unable to attend the meeting at the last minute, I found some of the other presentations fascinating and Joy Carter (former SEGH President), at Reading in those days, enrolled me into SEGH. This encouraged me (particularly after our sudden and unexpected return to the UK in 1996 after the Pakistani Government asked us to leave, reasons unstated) to build friendships, read the journal, and attend meetings. Through the SEGH meetings, in particular, I met a lot of fascinating people and learned a lot more than I could have imagined about the environment, geochemistry and possible influences on health. I also gave presentations or posters which were probed in the SEGH gentle but knowledgeable manner, helping develop my thinking on a number of issues. I have been delighted to serve on the SEGH board; SEGH has been a constant during periods of diminished support for environmental public health issues in the health protection arena (Stewart AG, Worsley A, Holden V, Hursthouse AS. Evaluating the impact of interdisciplinary networking in Environmental Geochemistry and Health: Reviewing SEGH conferences and workshops. Environmental Geochemistry and Health, Special edition. 2012; 34(6): 653-664).

Do you have any advice for young scientists setting out on their careers in environmental geochemistry or health sciences?

Don’t be afraid of cross-boundary work: that’s where exciting challenges and discoveries are to be made in any subject. Develop friendships and relationships with people outside your speciality, learn their scientific language and ways of thinking and undertake joint work. You never know where that will lead.

What do you consider to be the important topics for environmental-geochemistry-health related research in the future?

We need to continue our interest in elemental chemistry, but move beyond metals into organics, into volatiles, building relationships with air-scientists to look at the unseen pollution and health effects of fine and ultra-fine particles. I think linking the genetic fingerprint of cancers with specific toxins will enable us to identify, control and reduce/prevent specific diseases. However, this cannot be done by either geochemists or health professionals alone, but only in collaboration. Collaboration means both sides actively being involved in each other’s research proposals and activities, not just bolting two different approaches together.

What are some of your hopes for the future?

I would dearly like to see more health professionals involved with SEGH, but have run out of ideas how to involve them. I hope the younger generation of scientists can succeed where I have been unsuccessful.

Now that I am retired I hope to have some time to examine some of the environmental-health questions that have sat on my desk for 10+ years, such as: Does environmental iodine deficiency exist? What is the explanation for the global distribution of iodine deficiency disorders? What is the environmental input, if any, into lung cancer in North West England? Could some of the ill-health of deprived communities in industrialised countries be due to historical pollution, perhaps through trans-generational mechanisms?

 

On a personal note, Alex has made an important contribution to SEGH's encouragement of cross disciplinary work across geochemistry and health sciences, both in the UK and through European meetings.  Alex's tireless enthusiasm has helped to provide a platform from which the following generation of cross disciplinary scientists are less inhibited by the artificial boundaries.  Fortunately, Alex will continue to be engaged with SEGH, clearly with some exciting issues to pursue in retirement.

by Dr Michael Watts

British Geological Survey (SEGH webmaster)

Keep up to date

SEGH Events

Submit Content

Members can keep in touch with their colleagues through short news and events articles of interest to the SEGH community.

Science in the News

Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

  • Genotoxic effects of PM 10 and PM 2.5 bound metals: metal bioaccessibility, free radical generation, and role of iron 2018-10-09

    Abstract

    The present study was undertaken to examine the possible genotoxicity of ambient particulate matter (PM10 and PM2.5) in Pune city. In both size fractions of PM, Fe was found to be the dominant metal by concentration, contributing 22% and 30% to the total mass of metals in PM10 and PM2.5, respectively. The speciation of soluble Fe in PM10 and PM2.5 was investigated. The average fraction of Fe3+ and Fe2+ concentrations in PM2.5 was 80.6% and 19.3%, respectively, while in PM2.5 this fraction was 71.1% and 29.9%, respectively. The dominance of Fe(III) state in both PM fractions facilitates the generation of hydroxyl radicals (·OH), which can damage deoxyribose nucleic acid (DNA), as was evident from the gel electrophoresis study. The DNA damage by ·OH was supported through the in silico density functional theory (DFT) method. DFT results showed that C8 site of guanine (G)/adenine (A) and C6 site of thymine (T)/cytosine (C) would be energetically more favorable for the attack of hydroxyl radicals, when compared with the C4 and C5 sites. The non-standard Watson–Crick base pairing models of oxidative products of G, A, T and C yield lower-energy conformations than canonical dA:dT and dG:dC base pairing. This study may pave the way to understand the structural consequences of base-mediated oxidative lesions in DNA and its role in human diseases.

  • A systematic review on global pollution status of particulate matter-associated potential toxic elements and health perspectives in urban environment 2018-10-08

    Abstract

    Airborne particulate matter (PM) that is a heterogeneous mixture of particles with a variety of chemical components and physical features acts as a potential risk to human health. The ability to pose health risk depends upon the size, concentration and chemical composition of the suspended particles. Potential toxic elements (PTEs) associated with PM have multiple sources of origin, and each source has the ability to generate multiple particulate PTEs. In urban areas, automobile, industrial emissions, construction and demolition activities are the major anthropogenic sources of pollution. Fine particles associated with PTEs have the ability to penetrate deep into respiratory system resulting in an increasing range of adverse health effects, at ever-lower concentrations. In-depth investigation of PTEs content and mode of occurrence in PM is important from both environmental and pathological point of view. Considering this air pollution risk, several studies had addressed the issues related to these pollutants in road and street dust, indicating high pollution level than the air quality guidelines. Observed from the literature, particulate PTEs pollution can lead to respiratory symptoms, cardiovascular problems, lungs cancer, reduced lungs function, asthma and severe case mortality. Due to the important role of PM and associated PTEs, detailed knowledge of their impacts on human health is of key importance.

  • Interactions between polycyclic aromatic hydrocarbons and epoxide hydrolase 1 play roles in asthma 2018-10-06

    Abstract

    Asthma, as one of the most common chronic diseases in children and adults, is a consequence of complex gene–environment interactions. Polycyclic aromatic hydrocarbons (PAHs), as a group of widespread environmental organic pollutants, are involved in the development, triggering and pathologic changes of asthma. Various previous studies reported the critical roles of PAHs in immune changes, oxidative stress and environment–gene interactions of asthma. EPHX1 (the gene of epoxide hydrolase 1, an enzyme mediating human PAH metabolism) had a possible association with asthma by influencing PAH metabolism. This review summarized that (1) the roles of PAHs in asthma—work as risk factors; (2) the possible mechanisms involved in PAH-related asthma—through immunologic and oxidative stress changes; (3) the interactions between PAHs and EPHX1 involved in asthma—enzymatic activity of epoxide hydrolase 1, which affected by EPHX1 genotypes/SNPs/diplotypes, could influence human PAH metabolism and people’s vulnerability to PAH exposure. This review provided a better understanding of the above interactions and underlying mechanisms for asthma which help to raise public’s concern on PAH control and develop strategies for individual asthma primary prevention.