Every day all over the world, millions of women take the oral contraceptive pill. The substances in the pill may be altered a little by the body but for the main part, pass through the bloodstream and eventually into the urine. Urine ends up in water supplies and eventually back in the drinking water - so what has happened to those hormones during this process? Well, much of the hormonal material is still present but very diluted - so diluted in fact, that it is hard to say what effects it is having. Hormone replacement therapy employs similar hormones and these also get into the water supply. This issue is beginning to cause concern for a number of reasons.
What are Oral Contraceptives?
It was once considered that testosterone was the 'male sex hormone' and that progesterone and estrogen were the 'female sex hormones'. This is a great over-simplification, as both males and females produce an array of hormones, including the three listed above. Progesterone is the hormone associated with preparing a woman's body for possible pregnancy, and scientists predicted that it would be suitable for contraception as far back in the 1940s. It was not until the 1950s that clinical trials started. In the 1960s, both progesterone-like substances and estrogen-like substances were used, but over the intervening decades, progesterones have become the main drug of contraception and doses have become lower and lower. At the same time, the number of women using oral contraceptives has grown by many millions. Hormone replacement therapy was starting to be developed in the 1970s and by the end of the 1990s, millions of women were taking a daily dose of progesterone and estrogen to ward off the symptoms of the menopause. It is easy to see how the results of HRT and oral contraception, taken by millions of women, are ending up in lakes, rivers and the water supply.
Something fishy going on
Fish can change sex much more easily than mammals. We know that things like temperature have a big effect on fish sex-determination - the warmer it gets, the more female fish we have! Some scientists believe that in addition to temperature, sex hormones in the water supply are changing the sex of fish. This has been difficult to prove but the suspicion remains that the oral contraceptive pill might be causing drastic changes to fish populations. More worrying perhaps is the large number of fish with deformities in their sex organs, making reproduction impossible. Evidence is being collected all over the world to determine if hormones are really causing this problem.
Sperm - out for the count
You will doubtless have read news items about young males having a much lower sperm count than they did twenty or thirty years ago. The average young man in the UK, for instance, has a much lower sperm count than a man in his forties or fifties! Various causes for this phenomenon have been put forward, including the fit (or not...) of underwear, pesticides in the environment (many of which are surprisingly similar to hormones) and hormones in the water supply (see above). As with fish, conclusive evidence is hard to find, given that the number of environmental factors involved is too great.
What are the other possible risks?
Organizations like UNESCO and the UK's Royal Society have drawn attention to other possible risks associated with these substances in the water supply, including the increased incidence of breast cancer (in both men and women), the increased incidence of testicular cancer in young men, and the increasingly early onset of puberty in young girls. These are serious issues but it will take time to fully investigate any changes and even longer to establish the role of hormones.
What can be done?
Until we have much more research evidence, we can only suspect what these hormones are responsible for. It may be that we have to introduce far more effective water-treatment techniques to help prevent potential problems. Perhaps it would be better to take action before we fully understand the risks, in order to divert a potential disaster. Of course, oral contraceptives are the most widely used pharmaceuticals on Earth, but what about antibiotics and anti depressants? Both of these groups of drugs are used in vast amount and we - as yet - have no clue as to what effects they may be producing. The days when we considered that flushing the toilet was actually disposing of substances is long gone.
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