Are children more vulnerable to the effects of the pesticides present in our food, water and environment? Dr Howard Lee gives the facts

What is a pesticide? This is, in fact, a drug name for a poison, which includes things such as insecticides, disinfectants, herbicides (for plants) and fungicides (for moulds, etc). So in themselves they are dangerous.

Farmers count on levels of pesticides being low enough to kill insects and pests, but not to affect humans. Although pesticides can be beneficial to society, they can also be dangerous - and have been associated with everything from cancer and infertility to Gulf War Syndrome and eye abnormalities.

Many thousands of 'pesticide' chemicals have been created over the years, mostly in order to allow a greater increase in agricultural productivity. As a result, many of these products have been very widely dispersed into our environment. Whilst most of these pesticide products have undergone extensive tests to ensure their safety, no one really knows exactly what effects they may have on plants, animals and humans after a lifetime of exposure.

Some of them have a 'half-life' of up to a year - which means that their level of toxic action has only reduced by 50 per cent after a year from their first use!

What is the risk to children?
It is known that pesticides can cause a whole range of health problems, including cancer, damage to the nervous system and lungs, the reproductive system and the system responsible for our hormonal and immunity control.

Children are far more susceptible to the toxic effects than adults (apart from the large number who accidentally ingest pesticides). Relative to their size, children:

• Get proportionately heftier doses of the numerous environmental pollutants
• Breathe more air than adults
• Drink more water than adults
• Eat more food than adults. The food that children eat also differs, for instance, in that they typically consume larger quantities of milk and orange juice per pound of body weight than do adults. So, any toxins contained in foods will raise the relative exposure.

Other factors:

• Children have faster metabolisms than adults. This consequently speeds up the absorption of contaminants from the intestinal tract, so their vulnerability is increased.

• Chemicals may disrupt the hormone system. This can then influence how a child develops and grows. Sometimes birth defects are produced. There may also be influences in the reproductive and behavioural systems.

• Children live 'closer to the ground', where the highest concentrations of many air pollutants settle. They play on the lawn and in dirt, on carpets, etc, where they are also exposed to contaminants that are attracted to dust particles. At least one study has found that children whose lawns were treated with pesticides were four times more likely to have cancer of the soft tissues - and also have an increased risk of developing leukaemia.

• Children tend to put objects into their mouths, which increases their exposure - it has been found that children 'take up' into their blood stream half of the lead that they swallow, whilst adults absorb only about one tenth.

• Their developing bodies make children less able to metabolise (break down) and detoxify or excrete (remove from the body) some toxic substances.

Are young babies also at risk?
Yes, the following factors put babies at risk:

• They do not excrete contaminants, but actually store them away in fat cells, in the same way that adults do. This makes the poisons more available to affect their rapidly growing bodies.
• A baby's immunity system is not functioning as fully as an adult's, which means that they are not able to counteract any toxic effects as well as adults.
• The various 'protective' mechanisms are not developed in babies, during the first six months, so the various areas where the barriers of protection do not exist makes these areas vulnerable - particularly the developing brain and nervous tissues.
• Breastfeeding mothers transfer a good proportion of their lifetime accumulation of chemicals to their babies.

What about in the womb?
Children exposed in the womb are at the greatest risk of all. Many contaminants have an affinity for fatty tissue and during pregnancy women mobilise their amassed stores of body fat to provide nourishment for their growing babies - the contaminants in the fat are therefore passed on to the children.

Cellular structures are changing so rapidly during the embryonic/foetal stages that a toxic exposure at the wrong moment may well cause changes that will affect further development. These may be reflected in the especially vulnerable nervous system - perhaps producing changes in brain function in a subtle (behavioural) way, or even in a more serious way. There are current investigations, for instance, into the possible links between exposure to toxins in the foetal stage and developmental changes such as ADHD (attentive deficient hyperactivity disorder).

What next?
Increased knowledge and awareness of the potential hazards that certainly do exist in all areas of our lives - as far as pesticides are concerned - should make us all just that little bit more careful in everything we do.