A spokeswoman for Thames Water yesterday dismissed the report by scientists at the Royal Free Hospital, London, as 'highly speculative, incomplete and lacking in important detail'.
However, Friends of the Earth said the research would renew concern over the hormone-like substances which the authority has admitted is present in some of London's drinking water. Levels of one of these compounds are up to five times greater than that shown to cause transsexual changes in fish, a spokesman said.
Over the past 50 years, reports of a fall in sperm counts and congenital disorders of the male reproductive organs have increased worldwide. This has been linked with environmental pollutants which have oestrogenic (female hormone) properties.
Dr Jean Ginsburg and colleagues from the Royal Free compared the male partners of 260 women who were treated with hormonal drugs for infertility at the hospital over two periods, between 1978-83 and 1984-89. They found that compared with 1978-83, the proportion of men with abnormal sperm overall increased in 1984-1989, regardless of where they lived. Those who had sperm with abnormal movement rose from 20.7 per cent to 34.4 per cent, while those with deformed sperm rose from 1 to 12.3 per cent.
The group was then subdivided into men who lived within the Thames Water area (TWA) and those who lived outside it, and their sperm data analysed. According to a report in tomorrow's issue of The Lancet, '. . .sperm density and motile sperm density fell significantly only in those living within the TWA from 105 to 76 million sperm per millilitre, and from 61.7 to 40.8 million per millilitre, respectively, whereas in those living outside the TWA sperm density and motile sperm density remained unchanged'.
But Dr Ginsburg acknowledged that the men studied were not necessarily representative of the general population, and that water supply is not the only environmental factor peculiar to those living within the TWA.Reuse content