Homage to Gaia (34 page)

I am often told that I must be rich because of the patent royalties accumulating from the ECD invention. It is true that my name is on the patent for the ECD, but royalties there have been none. The US Government seized the patent soon after its issue in 1964. What happened was this. In 1958 Dr Sandy Lipsky invited me to spend a sabbatical at Yale University in the Department of Internal Medicine where he was a professor. I travelled there with all my family and spent eight happy months in the small Connecticut community of Orange just outside New Haven. It was a wholly different experience from the difficult times in Boston three years earlier. While at Yale I reduced the ECD to practice and it worked well enough to justify a paper, which Sandy Lipsky and I published in the
Journal of the American Chemical Society
.
Before publication, the Department suggested that it would be wise to apply for a patent. If the device was a success and the patent
granted we agreed a three-way share between the University, a patent agency and me. I was happy with this proposal; a third share seemed better than no share at all. But when the patent was issued in 1964, I received a curt notice from the US Surgeon General’s Department demanding that I assign the patent immediately to them. I refused equally curtly, saying that it was my invention, not theirs. Shortly after, a much more conciliatory letter came from the Dean of the School of Medicine of Yale asking me to reconsider and assign the patent to the US Government as requested by them. The reason given was that the Government was threatening to shut off grants to the Department unless I complied. The University told me that their agreement with the grant-funding agency included a clause that made all patents filed by the department I had worked in the property of the Surgeon-General. At the time I thought that the ECD was a minor invention and unlikely to be worth much. Certainly, I thought, not worth imposing hardship on my friends at Yale. Therefore, I assigned the patent. Looking back, I realize how naive I was to comply without at least a minor battle.

The early ECD was an extraordinarily difficult device to use. It was prone to peculiar, even false results that frustrated scientists accused me of promoting a bogus device whose predictions were of no more use than those of a fortune teller. At times, I tended to agree with them, and it took several months to discover the cause of the ECD’s
misbehaviour
. It was, I found, due to the complex behaviour of the ionized gas inside the detector, complicated by the absorption of vapours on the detector surfaces. The cure for the electron capture detector’s bad habits came from an encounter with Ken McAffee, a physicist at the Bell Telephone Laboratories. He had developed a way to observe the drift of electrons in a gas that involved applying brief pulses of electrical potential. It occurred to me that most of the difficulties with the ECD were due to the slow collection of the free electrons in a weak electrical field, and that I could resolve these difficulties by collecting the electrons using a brief high-voltage pulse. It worked well: the high-potential pulses overcame the
all-too
-frequent contact potentials and space charges that unpredictably either enhanced or opposed electron collection. Later, I found that by observing the frequency of pulses needed to sustain a constant electron population, the detector became even more stable and reliable. This method is now the one almost universally used. Its only drawback is a non-linear response to strongly electron-attaching compounds.

As I gained experience in the analysis of different molecular species by electron capture, I grew aware of an odd and interesting
association
between electron capture and biological activity. In 1960 and 1961, the last years of the Mill Hill apprenticeship, my experiments with the electron capture detector showed that a large proportion of the substances detected were in two main groups. The first group consisted of those important in metabolism, for example the alternate acids of the famous Krebs cycle, steroid and thyroid hormones, and other molecules important in the metabolism of living cells. The other group of substances the ECD detected were poisons, in
particular
, substances that interfered with metabolism, such as the nitro compounds, dinitrophenol or diodophenol, and all halogenated pesticides. The ECD also seemed to be uniquely sensitive to
cancer-causing
substances. Hydrocarbons, as oils or waxes, do not conduct electricity, nor do they react with electrons. But certain, special hydrocarbons, made of rings of carbon atoms fused together and called polycyclicaromatic hydrocarbons, capture electrons strongly. These unusual hydrocarbons included most of the carcinogenic ones. I could say that a tendency of a substance to capture electrons was all too often associated with carcinogenesis. Nowadays, whenever I come across a chemical substance that is strongly electron
absorbing
, I tend to regard it cautiously. I well recall critical scientists arguing that the apparent association between carcinogenesis and electron capture was illusory, since so many of the halocarbons were not carcinogenic. Vinyl chloride, chloroform, and
trichloroethylene
, they said, are substances safe enough for use as anaesthetics in surgery. Now, of course, we know them to be carcinogenic. I
sometimes
wonder about the phthalate esters. These ubiquitous
plasticizers
have long been a nuisance as electron-absorbing contaminants. We now suspect them to have a more sinister role as surrogate oestrogens.

It was tempting to speculate that the free electron might be a fundamental particle of biology as well as of chemistry and physics. It was a challenging coincidence that each alternate acid of the Krebs cycle (the major pathway for the oxidation of lipids and
carbohydrates
) was one of the few organic compounds that reacted
vigorously
with free electrons. These include pyruvate, oxaloacetate, fumarate, ketoglutarate, and cis-aconitate. It is still unclear whether this association is real or coincidental, but there is no doubt that a remarkably high proportion of electron absorbers are biologically
active, which makes the electron capture detector so important a device in environmental science.

I tried at Mill Hill to use free electrons in equilibrium with
molecules
at room temperature as if they were a chemical reagent. To do this I borrowed a sewing needle from Janet Niven, a friend from my virology days. I placed the needle in a stream of mixed argon and methane gases and applied 10,000 volts of negative potential to it. There was a visible blue glow and a current of several microamperes flowed in the gas. The electrons released by the strong electric field near the needle point rapidly bounced among the gas molecules and became slowed to thermal energies. I let them flow towards
substances
like the acids of the Krebs cycle to see what happened. The experiments suggested that in nature a free electron is indeed a fundamental particle of biochemistry. But before I could complete these experiments, it was time to leave Mill Hill. I published the preliminaries in three papers, two in
Nature
and one as a Symposium record.

While I was just experimenting, serious scientists were applying the detector to the practical analysis of pesticide residues in foodstuffs. In the USA, Watts and Klein of the FDA, and in the UK Goulden and his colleagues at Shell, together established the base data on the global distribution of pesticides and soon we realized that pesticides like DDT and dieldrin were everywhere and in all living things. This was the information that led Rachel Carson to write her seminal book,
Silent
Spring,
a book that warned the world of the ultimate
consequences
if these chemicals continued to be used by farmers against all forms of life that are not livestock or crops. This important book has changed the course of politics and, in many parts of the world, her gloomy forecast of a silent spring has come true. Although not, as she predicted, by pesticide poisoning, but simply by habitat destruction.

When I first heard of this use of the electron capture detector I was delighted. I shared with Rachel Carson a concern over damage to wildlife and to natural ecosystems. Some parts of the chemical
industry
reacted in a shameful and foolish way by trying to discredit her as a person. It did not work. Quite the reverse, it made Rachel Carson the first saint and martyr for the infant and innocent Green Movement.

As environmentalism evolved, Rachel Carson’s vision and the data itself became corrupted. I do not mean that the data gathered was false, but so sensitive is the electron capture detector that it can detect utterly trivial quantities of pesticides and other chemicals. Before we
used the ECD, it would have been quite easy and reasonable to set zero as the lower permissible limit of pesticide residues in foodstuff. In practice, zero means the least detectable amount. After the
electron
capture detector appeared, zero as a limit became so low that to apply it in full would cause the rejection of nearly everything that was edible. Even organically grown vegetables and fruit, even wild
vegetation
, contains measurable levels of pesticides, so sensitive is the device.

We needed common sense and the acceptance of the wisdom of the physician Paracelsus who said long ago, ‘The poison is the dose’. Even water is poisonous in excess. Even the deadly nerve gases are harmless at the level of a picogram, easily detectable by an electron capture detector. Unfortunately, common sense is a rare commodity. I
listened
with astonishment to a recent radio broadcast by a Green who argued that Paracelsus’s statement was no more than sophistry. Too many Greens are not just ignorant of science; they hate science. But despite this, they use the results gathered by the ECD and other instruments of science to support their crusades. The next
intervention
of the ECD into Green politics was in the relatively clear-cut problem of ozone depletion by halocarbons. I will describe my
personal
experiences in this ‘Ozone War’ in Chapter 8.

This is not the place to discuss the theory of the electron capture detector, but it is an opportunity to mention a few interesting theoretical aspects of the device which otherwise are rarely revealed. I find it helpful to think of the detector as a small reaction vessel like a test tube, holding a dilute mixture of free electrons in an inert gas, and I look on these dilute electrons as a chemical reagent. When an electron is in equilibrium with a gas at room temperature it behaves as if it were a very large particle, larger even than most of the
molecules
it encounters. Unlike the fast-moving electrons that physicists encounter, the cool electron is no tiny billiard ball or point charge, it is a sizeable wave packet with a wavelength of seven nanometres at room temperature. The large size of the cool electron makes encounters with molecules more probable and accounts for the great sensitivity of the ECD. The chemical reaction between electrons and molecules is what physical chemists call second-order, and some of the problems faced by analysts arise from this fact. If the electron capture detector were insensitive and the number of molecules present were vastly greater than the number of electrons, the device would be
proportional
and predictable in its response. Unfortunately, with the
compounds
it detects sensitively (those which the analyst seeks to
measure), the numbers of molecules in the detector are comparable with the number of electrons. In such circumstances, as textbook physical chemistry would tell you, the response of the detector to varying sample size is unlikely to be either proportional or easily predictable. Lack of sensitivity was not a complaint levelled at the electron capture detector. Even so, once we realized the possibilities of electron-attaching tags or tracers, that ultimate of detecting single molecules was the new destination.

We are still far from taking a grab sample of air or water and finding in it one molecule of tracer. The best we can now do is to detect 100,000 molecules of tracer in a cubic centimetre of air. We have shown that certain fluorinated hydrocarbons can label air masses and let us follow their movement over thousands of miles. Andrew
Watson
has used the same technique to trace the movement of water masses in the oceans. We can now detect directly one part in 10
¹⁴
, an improvement made possible by signal processing using gas-switching techniques. This improvement makes it feasible to detect and measure tracer at one part in 10
¹⁶
after a modest 100-fold concentration. Every year of this odyssey I have expected to find this simple device that anyone could make superseded by some impressive flight of high technology. Instead, its use seems to be expanding into new
territories
.

8

The Ozone War

A dense haze that steals the sun’s warmth and blurs vision so that half a mile is the limit of seeing sometimes spoils summer days in England. I was puzzled about this haze because I could not remember seeing it as a boy or even before about 1950. I suspected that the haze was some form of air pollution like smog, but smogs in England were wintertime phenomena, fed by the smoke from open fires. The
disastrous
smog of 1952 killed nearly 4000 people in one night, and is still in our memories, but since then smokeless fuel has replaced the sulphurous coal and the winter sky, even in London, is clear. So, what was the new miasma that spoilt the summer air? What puritan phenomenon stopped us from enriching our eyes on the
full-bosomed
and lush English countryside? My scientist friends had nothing to offer in explanation; they even doubted my memories of clean air before the Second World War. One person whose writing led me to suspect that he would listen with sympathy to my concern was Hubert Lamb. He was a staff member of the meteorological office in Bracknell and I went there to see if he could explain it.

In 1966 the Meteorological Office was in the new town of
Bracknell
. It was my first visit there and I was astonished to find that it was part of the Ministry of Defence. We English have always been
paranoid
about the weather but this seemed too much. Did we now see it as a national resource and treasure that needed the army to protect it? Intriguingly, the United States, then flexing its military muscles and obsessed with secrecy, put their weather bureau in the Department of Commerce. Perhaps they thought their weather good enough to sell. I propitiated the guards at this Ministry of Defence establishment,
they gave me a pass for my visit and took me to Hubert Lamb’s office. He welcomed me warmly, but seemed embarrassed by an office rule that required him to charge me for my talk with him. The fee was £5. To have a charge to make upon scientific visitors clearly upset him, but the bureaucrats imposed it and I did not see it as either a source of indignation or something that was a deterrent. We enjoyed a lively discussion on weather phenomena and I stayed for lunch and met others who seemed equally interested in my haze observations. What seemed to turn on their interest and make them take me seriously was my presentation of my observations as graphs. These compared the haze in Wiltshire, as it changed with the season, with that in Los Angeles. The smog in rural Wiltshire in the summer was almost as bad as that in urban Los Angeles.

By the late 1960s, it was a family ritual at Bowerchalke to measure the haze density using a sun photometer. We used a simple hand-held, battery-powered instrument that Robert McCormick, an NOAA meteorologist, had lent to me. Few such measurements were made in England and Hubert Lamb thought that visibility ranges, which had been observed daily at the meteorological stations throughout the British Isles, would have to do instead. They might provide some evidence on whether or not haziness had changed as time went by. My daughter, Christine, was as interested in this phenomenon as I was and had taken charge of the photometer readings. I arranged with Lamb for her to visit the Met office library and list the visibilities back to the start of the century. It was a disappointing exercise: no
discernible
trend was available from the records, but I am not the kind of scientist who is discouraged by one set of negative evidence. The haze of southern England looked to me like smog and I thought hard about gathering further evidence that would confirm or deny my ideas about its origin.

It occurred to me that a chemical analysis of both clean and hazy air might provide evidence of the origin of the haze. I could have
collected
haze particles that obscured the air by impacting them on sticky microscope slides or I could have analysed the air for sulphur dioxide and other products of combustion. I decided not to do either of these things, partly because the known analytical methods were not
sensitive
enough, but mainly because the presence of small amounts of haze-producing chemicals in the air does not tell us where the air came from. They could have come from natural or agricultural
emissions
as well as urban industrial sources. What would be proof would
be to detect in the country air some substance that originated
unequivocally
in an urban industrial region and which had no, or a
negligible
, source in the countryside. One class of substance that fitted this specification well was CFCs, then used in aerosol cans and in
refrigerators
. By far the greatest release of these compounds occurs in large cities. Better still, I had in my lab at Bowerchalke an apparatus able to detect and measure them easily, even at extreme dilution.

So, in 1969 we started at Bowerchalke the simultaneous
measurement
of haze, wind direction, and the chlorofluorocarbon, FC11. Later the same year I took these measurements at Adrigole in far western Ireland. At both Adrigole and Bowerchalke the CFCs were more abundant when the air was hazy and it seemed that my notion that the haze was man-made was correct. I published the results in the
Journal of Atmospheric Environment.
I chose this journal because my friend, Jim Lodge, who was then on the staff of National Center for Atmospheric Research, was its editor. Having a friend as an editor eases the otherwise tedious process of satisfying the self-appointed tyranny of the peer-review system. The editor could at least select reviewers from a panel of reliable critics who would treat the paper reasonably and not from those who wanted a chance to vent their anger anonymously.

The
Atmospheric Environment
paper suggested that southern
England
, and indeed, western Ireland, was sometimes during the summer immersed in the same kind of smog that plagued Los Angeles, but nobody outside my small circle of scientific acquaintances showed any interest at the time. In 1973 I collaborated with atmospheric scientists from Harwell and we showed that even in far western Ireland, foul air from Europe had ozone levels in it that were above the American Environmental Protection Agency’s safe limits. We published these findings in
Nature,
but again there was little interest from either environmental groups or the media. This small investigation might have ended, but I was curious about the fifty parts per trillion of one of the CFCs, FC11, in the clean Atlantic air. Had it drifted across the Atlantic from America? More excitingly, were the CFCs accumulating in the Earth’s atmosphere without any means for their removal? To find out, the only thing to do would be to travel by ship to the southern hemisphere and measure the CFCs as the ship travelled across the world.

Although I was surviving as an independent, I welcomed the offer from Reading University of a Visiting Professorship. It made the
publication of papers easier, and provided me with a respectable cover. It was an honorary arrangement and money never passed from me to the university or vice versa. It allowed postgraduate students
interested
in Gaia to work with me as research assistants. Andrew Watson, now a distinguished Professor at the University of East Anglia, and a friend, met me this way. Most of all I valued the chance it gave to discuss my science problems with Professor Peter Fellgett, chairman of the Department of Cybernetics. We would do so over lunch at his home, with his wife Mary, and at one of these working lunches, he suggested that I apply to the funding agencies, NERC (the Natural Environment Research Council) or the Scientific and Engineering Research Council, SERC, for support. He helped me to ask for a small grant to measure dimethyl sulphide, methyl iodide, and the CFCs aboard the research ship,
Shackleton
,
which was due to make its voyage to Antarctica and back later the same year. After some months, we heard from NERC that the academic review committee had rejected my proposal, but they asked if an NERC senior staff member, Mrs Howells, could visit me. She came to tea one afternoon in the early summer of 1971. We sat in the large sitting room of our Bowerchalke house. Our architect had designed it to conform to the village and it sat, hidden from view, perched above the village high street. The room gave a god’s eye view of the village and its pub. We were able to look down on the villagers, but the angle was too steep for them to see us. Double-glazing served to isolate us further.

Mrs Howells was a warm, pleasant woman, but she seemed
embarrassed
as she held her teacup and tried a piece of Helen’s home-made cake. I had asked for modest support to travel by ship to the southern hemisphere to measure the CFCs in the atmosphere throughout the journey, but as a civil servant, Mrs Howells could not, by herself, approve my application. All proposals had to be examined and judged by a committee composed of scientific specialists from universities and government departments like the Meteorological Office. Her bad news was that this expert panel had rejected my proposal, and Peter Fellgett told me later that it was rejected unanimously. Not only this, but appended to their report was the complaint that bogus proposals such as mine should not in future be presented to the committee, it wasted their time. Their annoyance stemmed from the fact that the senior chemist of the committee was sure that no one could measure the chlorofluorocarbons at parts-per-trillion levels, as I had claimed I
could do. He said the CFCs are amongst the most inert chemical compounds known and it would be difficult to measure their
abundance
in the atmosphere at the parts-per-million level; it was
impossible
to measure them at the parts-per-trillion level and therefore the proposal was bogus. Now this was a profoundly ignorant statement and could only have come from a narrow specialist, unaware of the advances in other branches of chemistry. Unfortunately, grant
committees
sometimes become cosy coteries of cronies who judge
proposals
from each other and each other’s friends. It is a danger insufficiently watched by the community at large who pay the taxes, which ultimately go to fund the grants.

Mrs Howells mentioned none of this, but she did say the other staff members of the NERC thought my proposal was a good one and the purpose of her visit was twofold. First, to check that I really could measure CFCs at the parts-per-trillion level and, secondly, to offer me passage on the
Shackleton,
which was travelling down to Antarctica in the coming November. The ship was due to call at Montevideo in Uruguay and they thought that if I wished to return from there, NERC would pay my fare. As far as the expedition was concerned, I would have to supply the equipment and any personnel other than myself. Because the academic committee rejected my proposal, NERC could only offer this limited support. I was delighted: I could easily afford to make a simple gas chromatograph for the voyage. I would travel and do the measurement at least as far as Montevideo myself; I could afford that much time. My graduate student, Bob Maggs, was keen to do the return voyage from
Montevideo
back to Wales in 1972.

We were then taking daily measurements of the
chlorofluorocarbons
at Bowerchalke, so I was able to show Mrs Howells just how routine and easy was the procedure. I must have convinced her that I was a professional scientist and not a crooked outsider
fraudulently
seeking the welfare of a grant. She saw it as an exciting project and gave her approval. The apparatus I intended to take on the ship was so simple that I was able to make it in a few days. It ran without failure throughout the six-month voyage. The total cost of the research, including the apparatus, was a few hundred pounds, but the discoveries of the voyage led to the ‘Ozone War’ and to the international research programme on the links between marine algae, DMS, clouds, and climate. Taken together, these must have given employment to thousands of scientists.

I spent much of my spare time in the next few months preparing for the voyage. The apparatus I took with me was simple. I arranged with the British Oxygen Company the purchase of four small cylinders filled with nitrogen gas. I used this carrier gas in my measurements and I decided on four small cylinders, not one large one, because I knew that leaks could all too easily develop in gas lines coming from cylinders, especially on a ship that is moving around all the time. The thought of finding myself half way to Antarctica with no gas for measurements was too embarrassing to contemplate. With four
cylinders
, at worst I would only lose a quarter of the total supply if a leak developed. In fact, no leaks developed throughout the course of the voyage. But it was good to have the backup.

I made sure that the boxes now filling for the voyage contained two or more of everything that I might need. To measure dimethyl sulphide was much more difficult a task than to measure the CFCs. I had a version of the flame photometric sulphur detector already working at Bowerchalke, but it was too insensitive and too
cumbersome
to contemplate using on the ship. I decided instead to extract the dimethyl sulphide from the seawater samples collected by the ship and then store them in the ship’s refrigerator. We intended to analyse them on the ship’s return. This worked well, and Bob Maggs did the analyses back in Bowerchalke in 1972.