Our Stolen Future

The dangers of endocrine disruptors:
an interview with Dr Theo Colborn

Dr Theo Colborn is the director of the World Wildlife Fund's Global Toxics Initiative. She is also one of the authors of a recent book, Our Stolen Future, which is about endocrine disruptors.

What are endocrine disruptors?

TOXICS: poisons

INITIATIVE: a new project or plan to deal with a problem

TC:
By accident!

I was asked to be a scientist on a team of Americans and Canadians who were investigating the environment of the area around Michigan, on the Great Lakes.

It was known that the area was heavily polluted, but there was little information about the health of the people who lived there.

"I was amazed by what I found."

Dr Colborn found that there were two problems with the previous research that had been done in this area:

1. There were separate pieces of research into individual species, but there was no research that looked at the Great Lakes as a whole.
2. People had studied only adult animals; they had not looked at the young of the species they studied.

Not many adult animals had died and so the American and Canadian authorities believed that the water was clean and everything was fine. They spent $50 million per year putting new, healthy fish back into the Great Lakes.

SPECIES: kind or breed (of animal, bird, fish and so on)

TC:
But things weren't fine ... Not at all.
Male animals, for example, were not reaching sexual maturity. Many species had thyroid problems. Some adults abandoned their young. Large numbers of baby animals died unexpectedly, and nobody knew why it happened. Birds were born with missing eyes, or deformed bills or deformed feet. This was when I became really worried.

Dr Colborn found out that chemicals were able get to babies inside their mothers' wombs. In other words, the chemicals could cross the placenta, which usually acts as a barrier to protect the foetus from harmful substances. The chemicals could also reach birds and fish as they developed inside their eggs.

The THYROID produces substances that affect how you develop and behave.

If something is DEFORMED, it is not the normal shape.

FOETUS: unborn child

PLACENTA: a part of the mother that lines her womb and provides nutrition to the foetus. It comes out after the birth of the child.

TC:
This meant that all aspects of development were probably affected, including intelligence. Of course, we couldn't test the intelligence of the animals, but we could test the people. We found that the babies of mothers who had eaten fish from the Great Lakes had lower intelligence than the babies of mothers who had not eaten fish. The babies of the mothers who ate the fish also weighed less when they were born, and had many other problems. And the mothers did not have to eat very much fish for the chemicals to affect their babies - just two to three meals of fish per month.

Dr Colborn and her team found that it was not easy to get their message across to people, because they were using new methods to test for poisonous chemicals and they were looking at new kinds of problems. Previously, scientists calculated how dangerous these chemicals were by looking at how likely they were to cause cancer.

TC:
Scientists didn't take the other risks into account. And yet we were finding more and more evidence that these chemicals could reach foetuses. We also found that they could mimic the body's natural hormones - and that this could have a disastrous effect on the body's endocrine system, which controls sexual development.

A HORMONE is something the body produces that is carried by the blood and effects the growth and development of the body's organs

NI: Are the safe levels that scientists set for chemicals still based only on the risk of cancer?

TC: Yes. And they don't realise that very small amounts can cause damage to natural development ... Of course, this is difficult to test. But we know that some chemicals bioaccumulate - that means that they are stored in our body fat for a long time, so they can build up in our bodies, little by little. As for other chemicals, like pesticides and plastics, we come into contact with them every day.

BIO: a prefix meaning relating to life and living things

ACCUMULATE: to get more and more and more as time passes

NI: These chemicals can spread to places far away from where they are used, can't they?

TC:
Yes. High levels are found in the Arctic, for example, in the bodies of Inuit people, and in polar bears and other wildlife, but they have never gone near such chemicals.

Let me explain how this happens.

Take the flood in Mississippi in 1996 as an example. We can see from aerial photos that the floodwater flowed down the rivers and out into the Gulf of Mexico.

Then the currents of the Gulf Stream took that water across the North Atlantic Ocean. Six weeks later, that water was off the coast of Newfoundland.

The rivers, seas and oceans are not separate, they mix together. Air also moves from one place to another.

And these chemicals stay around for a long time. Many of these chemicals take a very long time to break down in the body. (DDT, for example, has a half-life of 57 years in temperate zones.)

Map showing the approximate path of the Gulf Stream

The ARCTIC: the very far north regions of the globe around the North Pole.

The INUIT are the native ('indigenous') peoples who live in the Artic region. They were sometimes call "the Eskimo".

AERIAL: taken from high in the air above something - from an airplane, for example.

HALF-LIFE: the time it takes for a substance to break down to half of its original quantity.

The TEMPERATE zones are the regions of the earth lying between the very hot regions (the Tropics) and the very cold regions (the Arctic | Antarctic). Most of Europe, the United States, Japan, China, Australia, Argentina, Chile, and South Africa are in the temperate zones.

NI: What about the effects in the developing world?

TC:
Well the direct effects of people using some of these chemicals are terrible. It is particularly bad for farm workers in the Third World who don't have protective clothing and other ways to protect themselves. But it is very difficult to get accurate figures for people who have died, or who have suffered harm from chemical use. Many people who work in the fields must move from place to place to find work. Because they do not stay in one place, it is not easy to find them and test them.

However, even when it is possible to do tests, researchers are only studying adult workers. No-one is studying the children. But the evidence is there. We know that if adults are affected, then children are probably affected more strongly: they have already been affected by the chemicals when they were in the womb; they are also affected after they are born, and their bodies are much smaller than adults' bodies, so the same amount of chemical will have a greater effect.

NI: What can be done about this problem?

TC:
The most important thing is to find alternatives. For example, we need an immediate research programme to find new ways of curing diseases like dengue fever and malaria, which are carried by mosquitos. Right now, people still have to use insecticides like DDT to kill mosquitos. This kind of research will be expensive. The pharmaceutical companies will not pay for it, so governments will have to pay for it.

There are already some other projects in place, but progress is difficult.

DENGUE FEVER and MALARIA: deadly diseases that are carried by certain kinds of mosquitos

DDT: a pesticide used to kill mosquitos. It was found to be very harmful to animals as well.

PHARMACEUTICAL COMPANIES: companies that manufacture drugs.

NI: What can individual people do?

TC:
One of the things that I always tell people is to buy organic. That's good for the consumer's health and it means that the people growing the food don't get harmed by chemicals either ... The other thing I tell people is not to eat fatty foods because many of the chemicals that stay in our bodies for a long time are found in fat. Eat more beans!

ORGANIC: grown naturally, without using man-made chemicals

NI: What about your book, "Our Stolen Future"?
   What effect do you think it has had?

TC:
Well, it has been translated into 18 languages. The Japanese are particularly interested. Japan has put a lot of money into research into endocrine disruptors - far more than we have, here in the United States. We focus on treatment and cures, but we are going to have to change our priorities. The US needs to spend money on prevention, rather than hopelessly looking for cures that will come too late: the damage caused by endocrine disruptors cannot be undone.

PRIORITIES: things we consider most important