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Geologic Column

Does Geology Kill You?
Fred Schwab

When I chipped outcrops across New England decades ago, I imagined my geologic career might be capped by discovering a super-sized oil field or a new mineral (which I would name for myself), or pinning down the origin of the Appalachian "geosyncline." I never dreamed geologists could be in the forefront protecting humankind from the ravages of disease. Current events, and a new division of the Geological Society of America (GSA) called Geology and Health, bring new focus to the relationship between geology and medicine, biology, chemistry and other sciences. You probably already know radon and asbestos. Meet arsenicosis, vog, and H5N1.

Arsenicosis
Arsenicosis is chronic arsenic poisoning from drinking water. The initial symptoms are violent stomach pains, vomiting and delirium. Complications include gangrene, skin cancer and keratoses (large, horny tissue overgrowths) on the palms and soles of feet. None of these are on my "must have" list. Left untreated, early lightheadedness can lead to death.

An arsenicosis epidemic is currently occurring in Bangladesh because society, with all good intentions, acted without geological knowledge (see Geotimes, February 2006). Thirty years ago, the buildup of sewage bacteria in ponds and rivers contaminated the surface water, killing a quarter of a million children annually. UNICEF "solved" this health problem quickly: A massive tube well project — health officials considered groundwater inherently safe — allowed citizens to easily and cheaply tap shallow (less than 150 meters deep) subsurface water, immediately putting millions at risk of arsenicosis.

The massive deltaic complex that underlies Bangladesh was produced when the Ganges and Brahmaputra rivers deposited debris eroded from the Himalayas. Although the fine alluvial mud contains only traces of arsenic weathered from arseno-pyrite minerals in the mountains, the slow percolation of groundwater concentrates arsenic in the water consumed by unfortunate citizens. When the Bangladeshi government and UNICEF finally consulted the geologic community and tested the water quality, the epidemic was already well underway.

Vog
Hawaiians get to breathe vog (volcanic smog): a haze of gas and aerosols produced when volcanic gases like sulfur dioxide react with oxygen, water and dust. The dominant constituent is sulfuric acid, but small amounts of toxic metals such as selenium, mercury and arsenic are included as well.

Vog initially irritates the skin and mucous membranes of the eyes, nose, and throat, but eventually produces what is euphemistically described as "respiratory distress." The aerosols are just the right size to be retained by the lungs; their presence progressively degrades lung function and compromises the immune system. Residents and visitors near Kilauea complain of flu-like symptoms and a general lack of energy, wrongly blaming tropical cocktails and hula dancing. Vog is the culprit.

Vog-derived droplets of sulfuric acid fall as acid rain that damages crops, and the elevated level of lead in the bloodstream of many Hawaiians reflects the fact that acid rain dissolves nails, paint and metal in the ubiquitous rooftop rainwater-catchment systems. Lead poisoning from vog is a consequence of the lack of communication between health specialists and geoscientists.

H5N1
Fear of an H5N1, or avian influenza (bird flu), pandemic is all over the news. This viral disease normally infects birds and less commonly pigs. A "low-pathogenic" form causes mild symptoms such as ruffled feathers and a drop in egg production. (I can stand those.) A highly pathogenic form, however, has a mortality rate in birds approaching 100 percent, often within 48 hours. (No thanks!)

A current outbreak in Southeast Asia, attributed to the H5N1 virus, has caused the death or destruction of 150 million birds, making a lot of people besides Colonel Sanders anxious. The big worry is that the virus will mutate and begin to pass from human to human. Half of the people infected with H5N1 — previously healthy children and young adults — die. At the 2006 GSA annual meeting, an update on avian flu was a hot topic, in which geologists described how they are helping to map migratory pathways. Geochemists can also get involved, perhaps through examining the mobility of the virus.

How H5N1 propagates is unknown. Three possibilities exist: droplet transmission where an infected person sneezes or coughs near susceptible people; contact transmission from fluid passed by shaking hands or from doorknobs; and aerosol transmission, where evaporated virus-bearing particles are inhaled.

No vaccines are yet available to stop the disease. Antivirals such as Tamiflu and Relenza may reduce its severity and duration, but if bird flu spreads as aerosols, then arguably, vog experts should be brought into the picture. Simple and inexpensive protective face masks — such as N95 respirators like those worn by construction workers and which cost $1 apiece or surgical masks, such as those worn by dental hygienists and which cost 10 cents each — could be effective.

Future concerns
What about global warming? Infectious diseases adapt and adjust their range with changes in climate, just like most of life (see Geotimes, January 2006). Milder temperatures with less extreme seasonable variation increase the range for malaria and dengue-bearing mosquitoes. Like insects, pathogens even reproduce more often in warmer temperatures. (That's why my wife won't vacation with me in Arizona!) Disease isn't the only risk, however, as widespread adverse health effects, including more frequent and intense hurricanes and heat waves (the 2003 heat wave in Western Europe killed 20,000) are also possible.

We must become "medicinal geologists." Ignorance of geology, not geology itself, can make you sick. Learn about the relationship between geology and human health by checking out the new GSA Geology and Health Division, or begging, borrowing or stealing copies of the many books out there on geology and health.

Help humans spread the word before ignorance of diseases spreads.


Schwab is a professor of geology at Washington and Lee University in Lexington, Va. E-mail: schwabf@wlu.edu.

Links:
"Arsenic leaching into water from soil," Geotimes, February 2006

"Warming Linked to Disease Outbreaks," Geotimes, January 2006

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