I worked for 31 years at the Netherlands Institute for Fisheries Research in IJmuiden, which has a busy harbor serving the fishing industry. I started there as a trainee for a post of analyst. In the late 1980s I pursued a Ph.D. supervised by Udo Brinkman at the Vrije Universiteit Amsterdam on the topic of micro-contaminants. I started the development of analytical methods for the organic compounds polychlorinated biphenyls (PCBs), which were manufactured for use as cooling and insulating fluids in transformers, as well as the organochloride pesticide DDT.

“The simple fact is that large molecules with halogens do not degrade quickly in nature. Our natural world has not evolved to deal with cleaning up these chemicals.”

At the Fisheries Institute my strong environmental interest flourished. In those days, the 1970s, the Ministry of Agriculture and Fisheries in the Netherlands was already deeply concerned that these contaminants being ingested through the consumption of fish were a serious danger to human health. That’s why we started to develop analytical methods to determine more precisely what was going on with these chemicals in the food chain.

Over the course of time we not only found these PCBs in high concentrations, but also DDT and other pesticides, and, then, these brominated flame retardants. A picture began to emerge in which we could see that molecules containing chlorine and bromine, and these days, fluorine too, are very persistent.

Remember that these molecules do not occur in nature: they are manufactured for commercial purposes. The simple fact is that large molecules with halogens do not degrade quickly in nature. Our natural world has not evolved to deal with cleaning up these chemicals. After leakage they remain in the environment and move around: from water to air, from air to water. They enter sediments in water, and they get into organisms. Some of the contaminants get covered in the sediments as new detritus overlays what is already there. My important research papers are all on the chemical analysis and monitoring of these persistent organic pollutants.

Yes, I am now Chair of Environmental Chemistry and Toxicology. I moved here about 18 months ago, with most of my group of scientists, merging with a group already here. It was an interesting move for me, from a government research institute to a large university department with interests in analytical chemistry and also toxicology. We had outgrown the Fisheries Institute and we’ve now become a group that is totally focused on environmental studies. The group membership totals about 30, including doctoral students and visitors.

It’s important to note that my highly cited papers are interlinked. I guess everything really took off in 1998 when we had a Short Communication in Nature on the topic "Do flame retardants threaten ocean life?" (de Boer J, et al., Nature 394[6688]: 28-9, 2 July 1998). This rang a warning bell for many scientists to head in our direction, and in some sense it set our names up in lights. That paper was stimulated by the fact that in the late 1990s we had quite a number of beach strandings of sperm whales, for example. When we analyzed the liver and blubber, and also looked at harbor seals, we found significant concentrations of PBDEs. These mammals had fed on contaminated biota. Our Nature paper is one of the first drawing attention to flame retardants as contaminants.

With hindsight, we later realized that we had picked up PBDE contamination as early as 1978 in cormorants from the Rhine delta, which is heavily contaminated. We were using mass spectrometry, which showed the presence of bromine, and we suggested the contaminants were brominated diphenyl ethers, which we found on the staggering level of 0.1% by mass in lipids. Back then we were a small laboratory and we thought it was impossible that such a concentration could occur, so we dismissed the result as implausible!

What we know today, and I have made a number of contributions to this point, is that PBDEs are everywhere. They travel great distances, and have been detected even in the bodies of polar bears. They are present in everything from meat and dairy products, to fruits and vegetables, as well as indoor air and household dust. They are building up in animals throughout the food chain, and the level of PBDEs in our environment is rising steadily.

We presented the Nature results at the Dioxin conference in Stockholm in 1998. The attendant publicity triggered many requests for further research from national authorities and green campaign organizations such as Greenpeace, plus the bromine industry. Everyone had many questions.

I have tried to use the conflicts inherent in such diverse organizations to bring people together. For example, we have organized a number of symposia and workshops in which we brought people from Greenpeace, the regulatory authorities, and the industry to discuss the situation. That worked to our satisfaction in a way that was not true in earlier years when we found it impossible to get the players in PCBs around the same table; back then industry simply refused, stating that they had no problem.

Fortunately times have changed for the better, and industry realizes now that it is better to get into discussions with the scientists and the regulators. Our symposium on flame retardants in Amsterdam this year had 250 participants. I take some satisfaction from the fact that I have been successful in bringing such disparate organizations together to thrash out the environmental problems.

The first point to make is that there are about 70–75 commercially available brominated flame retardants, but only a half dozen or so have been seen in the environment. But that absence of evidence is not evidence of absence! For the remainder we don’t yet have the detection methods, and that’s what were working on.

The second point is that there is a lot of discussion of alternatives for brominated flame retardants. One example is retardants based on phosphorus rather than bromine, but that solution could be even worse than what we have now because they too accumulate in fish.

A third item is that quite a few groups are studying deca-brominated diphenyl ether, in which the molecule has 10 bromine atoms. This is a very large molecule (atomic mass: 960) and it is used in considerable quantities. It is present in large quantities in sediment but the central question is whether or not it bioaccumulates. It is so large that it’s possible it cannot enter the cells of organisms. So it seems the bioaccumulation is not high. But, on the other hand, it can lose some bromine atoms due to the action of ultraviolet light in the environment; then you end up with hepta- or hexa-brominated diphenyl ethers, which can accumulate.

Currently the environmental impact of these compounds remains a very difficult problem: we are doing everything we can to improve the analytical chemistry. The response of the authorities must be informed by the best possible scientific data.