Environmental Hormones and Pesticides
The hormones produced by the endocrine glands are chemicals that travel through the bloodstream and cause responses in other parts of the body. Examples include adrenaline, which helps stimulate physical activity, and estrogen, which is essential for female reproductive function. But hormones can produce both positive and negative effects, for example, some types of breast cancer are exacerbated by estrogen but studies also indicate that estrogen has a protective effect in combating heart disease and osteoporosis-related fractures
However those chemicals that interfere with the normal functioning of this complex system are known as "endocrine disruptors." Disruption of the endocrine system can occur in various ways. For example, some chemicals may mimic a natural hormone, "fooling" the body into over responding to the hormone. Other chemicals may block the effects of a hormone in parts of the body normally sensitive to it. Still others may directly stimulate or inhibit the endocrine system, leading, to reproduction or underproduction of hormones. Certain drugs are used to intentionally cause some of these effects, such as birth control pills.
But scientists now know that some man-made chemicals are linked to central nervous system damage, as well as diseases and weakening of the immune system. Some can even pass through the mother’s placenta to her unborn child. Research on children and women who regularly eat large amounts of toxic chemicals perhaps in fish that has been contaminated as a result of the dumping of industrial waste, show observable and measurable behavioural effects and learning deficits that are passed on from one generation to the next. This is all very worrisome as many man-made chemicals are very toxic and can cause cancer and birth defects. They also have an adverse impact on human ability to have children by limiting the normal growth of the reproductive organs. Other clinical health effects include a marked increase in diabetes, hormone-based disorders, behavioural and learning disabilities.
The US Environmental Protection Agency also says man-made chemicals that persist in the environment can accumulate in the fatty tissues of people and animals through the food chain and cause adverse effects to human health and the environment. But now that environmental activists in Bangladesh are aware of the harm these chemicals can cause they are calling on the government to control their use by levying a ''Green Tax'' on polluters on the principle of ''polluters must pay.'' The ''Green Tax'' will also need to have a provision for providing incentives to those who work to improve the environment.
Fortunately too, public awareness of the need to protect the environment has increased, and as environmental organisations and members of civil society make their voices heard, there is hope that the damage already done to the environment can be reduced.
This brings us to the matter of pesticides. Farmers to prevent fungal invasions, insect damage, and the growth of unwanted (and often poisonous) plants use pesticides. This has a positive benefit in terms of public health because fungi, insects, and non-crop plants can contaminate crops with many natural toxins. By using pesticides, farmers can maximize their efforts in the field, thus minimizing the cost of the produce to the consumer. While pesticides may be found in many products, the levels at which they are present fall far below the levels known to cause adverse health effects nevertheless there is a need to be aware of what these chemicals can do. (Source: The Bangladesh Observer, January 20, 2004)