Meharg Review

VENOMOUS EARTH
by Andrew A Meharg

Professor of Biochemistry
University of Aberdeen
Macmillan
L16.99 (UK) $29.95 (US)
Review by Richard Wilson

Chapter 1 The devil's water
Chapter 2 A natural disaster
Chapter 3 Fool's gold
Chapter 4 The verdant assassin
Chapter 5 Healing arsenic
Chapter 6 To frustrate the aim of justice
Chapter 7 Nothing green meets the eye
Chapter 8 The extraordinarily protracted process
Chapter 9 Joi Bangla!

    Arsenic has been known as a poison for millenia; yet the worst man made environmental disaster in history is the consumption of arsenic contaminated ground water in Bangladesh. It is man made not merely a natural disaster, because man did not have to drill wells without any check for arsenic. This drilling was encouraged by western countries.. As noted by Meharg, many experts have said it was a major disaster, and this reviewer has commented on the BBC and on National Public Radio (without any disagreement) that it makes Chernobyl look like a Sunday School Picnic. This disaster came to public attention ten years ago, and there have been many conferences with their volumes of reports either in print or on the web (many on this site), but no comprehensive popular book on the subject. This book is therefore very welcome. Professor Meharg is a biochemist part of whose heart, like that of this webmaster, stayed behind with the poor people of Bangladesh in their suffering. This led him to write this book to bring the issue to international public attention.

    Although the aim of the book seems to be to raise attention to Bangladesh and its problems, only the last chapter of the book is about specific solutions to the Bangladesh problems. Most of the book is about the acute poisonous effects and sometimes the benefits, of arsenic over the ages. Meharg in an easily readable fashion shows that the number of arsenic poisonings that have occurred throughout history is larger than most other poisons. I am fascinated by these chapters but am unable to judge their completeness and reliability. But they take up more than half of the book, and do little to elucidate the present day problems.

    The important part of the book comes only in Chapter 8 and is about details of the slow international realization that there is a problem. Although many of the historical situations described by Meharg have been the effects of acute exposures there has been over the ages warning after warning that even chronic exposures do something. This makes the behavior of these international agencies all the more puzzling. Why, for example, did the British Geological Survey lay themselves open to a lawsuit which was only dismissed for lack of jurisdiction? It was not merely the politicians and bureaucrats who made this error; it was the scientists who advised them. Why were scientists so mistaken? It is important to try to understand because a similar mistake may happen again with another poison in another country. Here, unfortunately, Professor Meharg only gives us part of the answer - that arsenic in chronic doses has had beneficial effects. In the last two centuries, arsenic in low chronic doses was used as a very effective medicine. Fowler's solution, a 2% solution of arsenic was used for for stomach and other ailments.. Arsenic compounds were used to treat syphilis, pellagra, trypanomiasis , malaria, sleeping sickness and more recently leukemia. A mystique had arisen that whereas arsenic is an acute poison it is beneficial at low doses. Yet as early as 1888 Hutchinson had published descriptions and pictures both of keratoses and skin cancer from excessive continuous use. These indications that low chronic doses taken regularly over a long period of time are harmful were ignored. As Meharg comments; "the long-term effects of arsenic exposure were too subtle for 19^th century physicians to fathom".

    Another important fact complicated the scientific understanding. In the 20^th century toxicologists had come to rely upon rats and mice to warn them about toxic, and carcinogenic, effects of chemical exposures. If rats or mice, exposed to a small fraction of a chemical in the food did not die or get cancer, why should people? These rodents refused to develop cancer or other ailments at what were thought to be equivalent doses. People even fed arsenic deliberately to their dogs because it gave their coats a fine sheen. This webmaster was mistaken also. In an early paper (1979), Crouch and myself compared carcinogenic potency in rats, mice and people and noted that arsenic was an outlier. But we looked for explanations and said, and did, nothing.

Meharg, in his table 8.1, points out that the US congress directed EPA to revise their standard by 1989 (which they did not do till 2001). But, writing in UK, misses the crucial scientific paper of Chen et al. in 1986 which showed that chronic arsenic doses produced an enormous numbers of internal cancers in Taiwan. The Taiwanese data suggested that the lifetime risk is over 1% at the US standard of 50 ppb - far higher than the risk of any carcinogen EPA purported to regulate. Yet EPA scientific committees ignored the problem till Smith in 1991 and myself and others soon after, found the paper and raised the alarm. WHO had urged a lower standard of 10 ppb and we urged EPA to set an emergency standard of 10 ppb. But the US EPA and then the American Water Works Association produced estimates of $180 million to $590 million annually to meet a lower standard of 10 ppb and claimed it was too expensive. Although USA is a rich country and could afford this sum, it is likely that they are overestimates based upon meeting the new standard immediately. Overestimates of the cost of meeting standards are common. Other organizations in the US have acted. The Los Angeles Water district brings water containing arsenic from lakes east of the Sierra mountains to Los Angeles. In 1991 data suggested that much of the water would exceed the proposed new 10 ppb standard. But by 2001, changes had already taken place and there were few exceedances.

    Meharg discusses the work of the Chilean scientists that Smith brought to our attention. That work shows that lung cancer incidence among those arsenic exposed exceeds that of heavy cigarette smokers, and that the number of cases in this cohort alone exceeds the number of cases of cancer attributable to the atomic bomb explosions in Hiroshima and Nagasaki studied by the Radiation Effects Research Foundation.

    What should we do next? Alas there is no simple and cheap solution. Bangladesh has also been just as slow to react as the USA whereas haste was much more justified in Bangladesh by the sheer magnitude of the problem. A warning flag was raised for West Bengal in the 1970s by Saha. Yet western international organizations (World Bank, UNICEF, BGS encouraged widespread drilling of tube wells without testing for arsenic. This makes the whole western world responsible. Tube wells were being drilled even after scientists in Bangladesh raised the issue in early 1990s The arsenic levels in 25%(!) of wells exceed the old

    It is clear that a key is measurement. In 1989 the arsenic measurement capacity of the country in was estimated to allow for the measurement of each well once every 300 years! But Meharg misses another crucial point: the intercomparisons of even laboratory measurements showed an appalling lack of consistency. The field kits are worse. It is not trivial to measure arsenic in parts per billion when many other contaminants are present at varying amounts and parts per million. For surface waters, such as a return to a dug well, the problem may be simpler - one need not measure arsenic but one has to measure coliform bacteria to be sure that the sanitation is adequate. world standard of 50 ppb. At meetings organized by Dhaka Community Hospital and Jadavapur University in February and December 1998 two immediate actions were proposed. Small scale arsenic purification at an individual household level as a temporary measure; and a drilling of deep tube wells to replace the shallower ones. A call was made for a proper national water policy. After a 2002 conference organized by the WHO for the new Bangladesh government, a national policy of return to surface waters (such as a use of sanitary dug wells or rainfall collection) was promulgated. But there is a danger: the tube wells were installed for a reason - to avoid the microbial contamination of the surface (dug) wells that were present in much of the country. A return to such surface wells would be fraught with dangers. Meharg quotes the conclusion of a 2003 WHO report: "the risk posed by microbial hazards is greater than that for arsenic.." so that new wells must be dug with much greater regard for sanitation than heretofor. Some of the first attempts to return to dug wells have not been effective, but it is hoped that those installed with a full recognition of WHO standards will be effective. This return must be done with full regard to sanitation.

The yearly meetings held by Dhaka Community Hospital and Jadavapur University have shown increasing frustration with the lack of progress. Meharg points out a basic problem: there is inadequate organizational capacity in the country. This was captured well by a report, Crisis of Capacity, by Ms Patel, a Harvard Student who lived several months in the country studying the question. In 1978 it was generally agreed that water can be purified at the household level - but even this shows problems as the recent reports from Jadavpur University show. It should probably only be a short term solution. Filtering in sand has been an option in many places but villagers are reluctant.. Tubewells sunk to a depth of 200 metres are free of arsenic and are being installed in many places. Meharg reports that villagers in Samta are reluctant to use them because of their bad experience with the shallower tube wells. A team of scientists from Columbia University and others report different results from villagers in Araihazar upazila. The scientists seem to have successfully persuaded the villagers to use the central deep tube wells.

I would like to have seen this chapter expanded with descriptions of the successful remedies. Although, therefore, this is a book which belongs on the bookshelves of any serious student of arsenic problems it is primarily a book about arsenic throughout the ages, and must be supplemented by one of the more detailed conference books such as the 2003 BUET conference available on the web)..