The environment is full of chemicals which can harm your foetus, discovered pregnant ecologist Sandra Steingraber. And although far better than formula for babies, breast-milk could be the most contaminated food on the planet, writes Victoria White.

Sandra Steingraber, a 38-year-old environmentalist, was pregnant for the first time and suddenly the world was a very dangerous place.

"Hey Jeff?" "Mmm."

"I'm trying to figure something out."

"What's that?"

"Not a single one of these pregnancy magazines encourages mothers to find out what the Toxics Release Inventory shows for their own communities."

"You did it though, right?"

"Yeah, I looked it up on the Internet."

"And?"

"And McLean county is one of the top counties in Illinois for airborne releases of reproductive poisons."

She goes on: "I detail for him the results of my research. The biggest emissions of fetal toxicants are hexane from the soybean processing plant and toluene from the auto plant. My list also includes glycol ethers and xylene. All are solvents."

Jeff, husband and narrative device, doesn't get the best lines.

"Jesus," he exclaims.

Having Faith, Steingraber's latest book, charts the process of having Faith, who is now a (seemingly) perfectly formed four-year-old. So Steingraber shouldn't have worried, should she? She's just a paranoid, po-faced American, and we're alright, Sandra.

Steingraber, in Cork recently to address the Irish Doctors' Environmental Association about fetal and breast-milk contamination, in the context of the proposed incinerator in Ringaskiddy, has a tall, slim, puritanical seriousness about her and her book reflects that. But once you've read it, you feel ready to become a missionary too. She brilliantly exposes how the myth of the "placental barrier", shielding the fetus from harm, has persisted in the teeth of the facts.

Steingraber says: "We have inherited a cultural idea about pregnancy as a private, sacred place. It goes back to the old Victorian idea of a woman as a sealed place. The new image is that of the fetus as an astronaut in the mothership." In fact, she says, a pregnant woman is more part of the ecosystem than she has ever been: she's eating, drinking and breathing more and has 40 per cent more blood.

Steingraber was not anything like as easily reassured about environmental risks as the rest of us like to be in pregnancy. Some, having discovered that the university in which they worked used six different pesticides, might have taken comfort in the fact that US research said no "clear inference" of their potential to damage fetuses could be drawn. But Steingraber found that this was not surprising - the research simply hadn't been done.

A more recent study of 700 women in California showed an increased risk of fetal death due to birth defects among babies whose mothers lived near crops on which certain pesticides were used. In Finland, children born to women whose mothers worked in environments in which pesticides were used were found to have twice the risk of cleft lips and palates, while in Spain they were three times more likely to have this birth defect. The risk of undescended testicles in boys is significantly increased in babies whose mothers work with pesticides in Denmark and Spain, while in Norway women who work in orchards or greenhouses are found to be at greater risk of giving birth to babies with hydrocephaly and spina bifida.

Pregnant women are beaten over the head with advice to take folic acid - and, as Jeff points out: "Pregnant women are constantly being told what to do. No coffee. No alcohol. No sushi. Stay away from cat faeces - but information about risks whose elimination would have political and economic consequences is suppressed.

Steingraber took to drinking bottled water when she found that, despite official reassurance, Illinois drinking water contains levels of fertiliser sufficient to kill baby frogs, but she knows how ineffective this private act is - the most efficient way to expose yourself to the chemicals in tap water is by turning on the dishwasher.

It's not surprising that Steingraber is more questioning than that rest of us. She may look the picture of health today, a 40-something with an angelic seven-month-old boy clasped to her willowy frame, but at 20 she was lying on a hospital bed with newly diagnosed bladder cancer. Had she not insisted on a colonoscopy, she might not be alive. An aunt living close by had had the same cancer - well, it's genetic, isn't it? Bit of a problem with that theory - Steingraber's adopted. She looked for environmental causes and charted them in her book, Living Downstream.

The state of Illinois, like many others, bans her from access to her birth certificate and she has no knowledge whatsoever of her birth family: "The first subject I studied was evolution, the tree of life, the root of its origins," she says. "I suppose I studied the big family as a compensation for not having ancestors."

The most moving moment in the book comes when, in the middle of Steingraber's exhausting struggle to breast-feed for the first time, the midwife looks at the baby and tells her mother: "I think she looks like you".

"I'm adopted," says Steingraber, automatically, so used is she to discounting the resemblance some see between her and her mother.

"So am I," replies the midwife slowly, then takes out a picture of her own daughter: "Bright eyes, mile-wide grin, she looks like a miniature version of her mother".

It's not just her own health history which makes Steingraber sceptical, however. All you have to do is take a clear-eyed look at some of the public health scandals of the past affecting fetuses and babies, and it should shake the "it'll do" attitude out of you. Steingraber rehearses them in painful detail. The tests for Thalidomide's effects on fetuses were indeed carried out, she writes - "as a vast, unintentional experiment on humans that ran almost four years".

The fragile miracle that is fetal development is tragically shown by the fact that "pills taken between days 35 and 37 resulted in babies with no ears, whereas pills taken between days 39 and 41 resulted in no arms. Days 41 to 43, no uterus. Days 45 to 47, no leg bones. Days 47 to 49, deformed thumbs.

Many women who took those pills on those Red Letter Days are still alive, but hopefully they have been empowered enough not to blame themselves. They should have been protected, as American women were, by health professionals like Frances Kelsey, who refused to legalise Thalidomide in the US. She simply remembered that the embryo had been affected by quinine and by rubella. She "believed the placenta was permeable when others did not."

More closely mirroring Steingraber's concerns in Having Faith, however, is the appalling story of Minamata in Japan. Here babies born with what seemed like cerebral palsy were discovered to have "congenital Minamata disease" - some were blind or deaf; some had unusually small heads and deformed teeth; some had tremors and convulsions. Even when it was conclusively proven that the birth defects were caused by methylmercury dumped into the bay by the Chisso company - even when pregnant women with too much of the poison in their hair were routinely advised to have abortions - it went on dumping methylmercury into the local water for six more years, until its method of making plastic was no longer economic.

Are you feeling so confident now that you'll be alerted to any environmental danger which might affect your unborn baby? Unfortunately, you're not out of the woods when your child is born, either. Even if you're one of the few Irish women not dissuaded from breast-feeding by the scandalous apathy of the Irish health service, you can hardly rest easy in the knowledge that you are feeding your child, in Steingraber's words, "the most chemically contaminated food on the planet".

Environmental poisons are concentrated up to a millionfold by the time they have bonded with the fat in your milk. You then off-load this cargo on your first child, cleaning up your act considerably by the time you feed later children.

The real baddies here go by the name of POP's (persistent organic pollutants). Related to carbon, they are found in materials as diverse as hydraulic liquid and pesticides. They can cause cancer, suppress the immune system, and interfere with brain functioning and fetal development. The average British breast-fed child is getting 17 times the dose considered tolerable for an adult of brands of these poisons known as PCBs and dioxins. These substances are replaceable in industrial processes - and they are being replaced, so that levels of breast-milk contamination are going down in most heavily industrialised countries. However, they stay in the ecosystem for generations; and in the absence of a determined international effort to ban them, poorer countries are still using them. And sadly, other poisons are queuing up to take their place: chemicals called PBDE's found in commonly used flame retardants interfere with thyroid functioning and neurological development and may be carcinogenic, while a whole new class of industrial chemicals called "aromatic amines", which are found in dyes, foams, pesticides and a range of products, are card-carrying carcinogens.

Let them drink formula! That's a line of reasoning which drives Sandra Steingraber over the edge. "When I wrote this book I said I would have failed in my duty if even one woman was put off breast-feeding."

Reading Steingraber's log of the benefits of breast milk I got very, very angry - despite the fact that a UCD/Food Safety Authority/

Southern and North Western Health Boards study is indicating that our breast-milk is far less contaminated that that of most countries in the industrialised world, our breast-feeding rate is even lower than the very low rate in the US. And yet Steingraber quotes an expert estimate that formula-feeding - or not being breast-fed - leads to conditions which cause the deaths of 4,000 babies in the US a year. It just isn't possible to believe that Irish babies don't die for the same reason, and yet the Department of Health will not prioritise this basic building block of preventative health care.

The illnesses and conditions which breast-feeding is thought to militate against include respiratory infections, gastrointestinal infections, urinary tract infections, middle ear infections, bacterial meningitis (bored yet?), Sudden Infant Death Syndrome, high blood pressure, allergies, asthma, juvenile diabetes, Crohn's disease, ulcerative colitis, juvenile rheumatoid arthritis, obesity, cancer and Hodgkin's lymphoma. If that isn't enough, more than 20 studies have confirmed that breast-fed kids are cleverer. One study found they had IQ scores three to five points higher than their formula-fed counterparts at 15.

In addition, says Steingraber: "There are hundreds of elements in breast milk which we don't even know the meaning of - signals which seem to begin brain development and affect the immune system, things which seem to boost IQ." She says that as a scientist, she's used to contradictory findings, but on the issue of breast-feeding, "the data are absolutely clear, and there is no study which contradicts them"; that no matter how contaminated a mother's milk is, "it is vastly superior to formula". Are we going to wait, she asks, until breast milk contamination kills as many babies as bottle-feeding does - or are we going to demand that clean breast milk is "a basic human right"?

So why aren't women demanding this? Steingraber gently reminds me that it took women 70 years to get the vote. "I feel optimistic about all this," she says. "It's the optimism of someone who's been a cancer victim."

Her little boy, tired of making me fall in love with him, is determined to have another feed. "His name is Elijah, after Elijah Lovejoy, an early slavery abolitionist. When I say Faith's name, I see the future, but when I say his name, I see myself in a long line of social responsibility, and as an adopted person, these roots are important to me."

Having Faith: An Ecologist's Journey to Motherhood is published by Perseus Press