QI always had an interest in environmental sciences, and studied marine sciences at university in the UK, where I got interested in pollution issues, then went on to do a PhD in atmospheric pollution at the University of Southampton.Yes, the two UK universities which have the most dedicated and active oceanography departments are Bangor, in North Wales, where I did my undergraduate degree, and Southampton, which is now considered a major international centre for marine research. All over, really. I have always moved around a lot, because my father was in the British Army. I was born in Malta, another small island, and we spent time in Germany and various parts of the UK. Absolutely, and with two universities and four research positions before I came to Bermuda, that's a fair description of my career, to date anyway. After my PhD, I spent three years in Canada, at the National Water Research Centre, and then periods at different universities in the UK. The mercury, estimated at between 4,000 and 8,000 tons a year world-wide, is emitted from various sources. About a third are direct emissions as a result of human activity, another third are re-releases caused by human activity, for example, when land is flooded, and the final third are natural. There can be high concentrations of mercury in coal and in crude oil. Yes, but also volcanic. Yellowstone National Park in Wyoming releases more mercury than all of the power stations in the state, but coal combustion is one of the major man-made causes of mercury emission, and the one that they are trying hardest to regulate in the US. China and South Africa are also major sources of mercury from coal.

Mercury is a metal, but it is volatile, liquid at room temperature, and it evaporates in air. As vapour, it can be transported very long distances in the atmosphere, and that's why it's a global problem. It undergoes a chemical transformation in the air, into salts or very fine particles, and when it gets deposited in rain or snowfall, it can undergo a further transformation, what we call methylation; this new form, methyl mercury, is readily absorbed by animals and concentrated in the food chain.

In the case of the effect on Bermuda's fish, the plankton will take up the methyl mercury, and it is passed on to the small fish which feed on plankton, and so on up to fish like tuna and swordfish; at each step up that chain, this form of mercury gets more and more concentrated, so that the predators at the top of the food chain can have very high levels in their flesh. But fish is an excellent source of nutrition, and there is no reason for general concern.

: Healthy adults, male or female, would have to ingest a huge amount of mercury to be at risk, more than they could get from eating local fish. It became a big issue in the Sixties, with the discovery of mercury poisoning at Minimata Bay, in Japan, and in the Seventies, people in Iraq were poisoned as a result of eating seeds contaminated with mercury.

And, of course, farther back in history, Lewis Carroll wrote of the Mad Hatter in ; real hatters were neurologically damaged back then by the mercury used in the treatment of beaver pelts for hats, but they were exposed to huge amounts of mercury on a daily basis.

As the mechanism of toxicology became better understood and the science advanced, the focus has changed, particularly in the last ten or twenty years, to chronic sub-lethal effects. In other words, what is the cumulative effect of being exposed to a little bit over a long period of time?

: I have to remain optimistic, or I would go mad as a hatter! It is an uphill battle, but governments are more responsive and intervene earlier than they did in the past. But there are always new challenges; everyone's heard of DDT and PCBs, but there are new chemicals with very similar properties which are still being produced and used, and detected all over the world, in oceans and even in Arctic wild life like polar bears.

But I think we know enough about how chemicals behave in the environment that predictions can be made and controls introduced earlier than in the past. Man-made pollution is not new, but the greater concern now is that the problem is truly global, whereas it was once more localised.

: It's an ongoing area of research here at the Bio Station. For many years, we have run a summer course on marine ecotoxicology, and it is just the study of pollutants and their effect on the ecosystem, either on individual species in the system or the system as a whole. One of the scientists here is a specialist on coral reefs, and one of the better-known studies looked at the effect on reefs of anti-fouling paints used on boats. It was found that, even at very low levels, some of the chemicals used in these paints could reduce the ability of corals to grow, and that led to some restrictions on the types of anti-fouling paints used in Bermuda.

The summer course has been running for 25 years, and it provides an opportunity to go back to exactly the same areas, and perform various measurements.

We have been doing that in Hamilton Harbour and Harrington Sound, and it's a way of demonstrating the tools we use to students, so that they can take them and use them elsewhere.

For example, just one of the tools of ecotoxicology is that you can take shellfish, say scallops, and put them out at a site where you suspect there may be contamination, perhaps at very low levels; if you put the scallops there for three months, they may accumulate pollutants and you may be able to measure enzymes that appeared as a response to that exposure, or you can measure restricted growth compared to a healthy population somewhere else.

You are not directly measuring pollutants, but the 'bio-markers' that measure the response of the organism to pollution.

: We are actually measuring them in the air in Bermuda right now. One of the programmes that I manage here is the Air Quality Programme, which is funded by Government to monitor the quality of ambient air, and the main focus is the likely sources of air pollution: the incinerator, the Belco plant, and road traffic.

The programme has been running since 1987, and we have a good picture of the situation; the air in Bermuda is generally very good, very clean, but there are localised areas of concern.

And although we talked of a local effect of mercury emissions from the US, the story is not all 'gloom and doom'.

Acid rain was a major problem 25 years ago, with forests in Northern Europe being particularly badly affected, but partly as a result of international action to reduce emissions, Bermuda's water has become less acidic, and is approaching the quality of unpolluted rain water.

People should just be aware of the impact that their everyday actions have on air quality: driving, waste disposal, electricity use, and people need to be aware of the connection between their activities, and the consequences of them.

Looking ahead, in ten years, road traffic pollution could be a major problem. Already, we have one of the highest densities of road traffic in the world, some 730 vehicles per 1,000 population, and a lot of them tend to be very dirty, in terms of emissions.

There are a lot of diesel vehicles, and a lot of two-stroke engines, which are less clean than four-stroke. We have no statutory emissions testing in Bermuda, although I know there are plans to introduce it. Traffic growth is a cause for concern.

Globally, it will require serious political and social commitment to develop sustainable, pollution-free sources of energy, and it would require economic sacrifices for governments and individuals. But a lot more could be done in Bermuda to reduce our energy consumption.

I think I have only seen two or three places here using solar power, and I think a lot more use of solar power could be made here, particularly for heating water and providing low-level lighting.

: Actually, I first came to the Bio Station as a graduate student, way back in 1989. I came on one of the summer courses I am now teaching, and I never expected I would have the chance to come back!

But a couple of years ago, I saw a position advertised here, and I was looking to move on at the time; a new position, a new challenge, and this seemed ideal.

It's worked out very well, it's a great place to do research, and to live.