Can Male Infertility Be Affected By PCBs

There are, of course, no outward signs that would indicate the fertility of a man or woman. Generally speaking if after about a year of unprotected sexual intercourse conception hasn’t occurred, thoughts about infertility can develop. The incidence of male and female infertility is roughly the same, in an infertile couple the chances of the male or female being infertile is in the range 30% to 40%. However, studies show that as many as 5%, or one in twenty, of males is infertile.

For a man, concerns about infertility are usually first addressed by having his sperm analyzed. Male fertility is measured by the so called "semen profile". The minimum criteria for a semen profile to be considered fertile is as follows:

• an ejaculate volume of at least 2 milliliters
• at least 20,000,000 sperm present per milliliter of ejaculate
• at least 50% of those sperm being motile
  (NB. Motile means that the sperm are moving in a purposeful direction rather than in a circle or being immobile.)

Following those tests, medical experts will then test to see how well the sperm can escape from the ejaculate. This is important because the sperm has to be strong enough to penetrate the females cervical mucous and then the outer covering of her ovum. (The strength and ability of the sperm to penetrate an ovum is tested under laboratory conditions on specially prepared hamster eggs.)

Whilst other articles on this web-site discuss general causes, prevention and treatment of male infertility, there is one alarming environmental factor that has and will continue to impact on male fertility for many years to come. That is the occurrence and accumulation of Polychlorinated Biphenyls in the environment.

Since the 1950s there has been a steady fall in the sperm count of males. This fall in men’s sperm count and motility is still continuing to the extent that it is estimated by the end of the 21st century the average male sperm count will actually fall below 20,000,000 per milliliter of ejaculate! This obviously raises questions about how the medical profession will cope with and treat a potentially massive rise in male infertility. One possibility is of course an increase in artificial insemination and IVF (in vitro fertilization) of the ovum.

The most plausible explanation for the fall in men’s sperm counts is an environmental one. In the 1950s when the trend was first noticed scientists made a link between it and chemical pollutants in the environment that ‘mimic’ the female hormone estrogen. These chemicals were pesticides such as DDT, which was in heavy use then. However, with the decline in use of DDT the fall in male sperm count also continued on through the 1960s and1970s. It was during the 1970s that scientists determined that a number of chemical pollutants were responsible for the continuing fall. However, the chemicals causing the most concern were a group of compounds known as PCBs (Polychlorinated Biphenyls)

PCBs were first manufactured in the late 1920s. They can be oily liquids or waxy solids. Due to their physical properties being very chemically stable, having a high boiling point and being excellent electrical and heat insulators they were put to a wide range of uses in industry; electrical components, paints, plastics, rubber and hydraulic equipment. Their chemical stability makes them very durable compounds, being not easily broken down or destroyed. If not disposed of securely and correctly PCBs accumulate in the environment, they are then distributed by water and air systems and find their way into our food chains. Despite the fact that since the late 1970s the use of PCBs has been severely restricted and banned in many countries, because of the improper disposal of them in the past they remain a significant environmental threat and their presence in our ecosystems will remain for many decades to come.

PCBs are also known to have an effect on the development of male reproductive organs whilst developing in the womb.

The tolerable level of daily intake for PCBs has been set at 20ng/kg of body weight. Or put another way, an adult weighing 100kg should consume no more than 0.000002g of PCB per day. A miniscule amount and impossible to detect unless the food and or water source are subject to the most stringent tests. Without causing over concern, if drinking water or eating food ‘in the wild’ ensure it is well prepared and as clean as possible. This is especially important when dealing with fish which absorb and accumulate PCBs from water sediments and their food.