Sir: Concerns about the reduction in the quality and quantity of human sperm are timely ("Watch out, oestrogen about", 26 July). Further research is clearly needed but some conclusions can already be drawn and some actions should be taken now.
Since the 1970s, certain pesticides, such as kepone and DBCP, have been known to cause sterility in humans. Since that time, too, the very large gaps in our knowledge of the potential toxic effects of the 60,000 or more chemicals widely used in many industrial societies have been noted.
In 1995 we now have a list of chemicals that have oestrogenic effects and which may adversely affect human sperm. Some of these chemicals have been withdrawn but, even so, several still persist in our environment.
The policy and regulatory questions that arise are:
1. Why have government departments not acted since the Seventies to include effective and automatic tests of old chemicals and new chemicals with regard to their effects on human sperm?
2. Why have government departments not openly acknowledged to both users and consumers that the vast majority of chemicals now cleared for use in the UK lack complete toxicity data?
3. Why have governments and some scientists been so concerned to ensure that there have not been false positives (ie, finding safe chemicals to be dangerous in toxicity testing)? The primary concern should be with avoiding false negatives (ie. finding dangerous chemicals to be safe in toxicity testing).
4. Why have government departments accepted industry arguments that the UK needs more cost-benefit analysis and risk assessments, when such methods have proved notoriously unsuccessful at picking up known or suspected health hazards in our environment?
What is needed is a clear policy of toxics reduction, preventing exposures to known and suspected hazardous substances and also to chemicals with unknown effects, rather than debating endlessly theinadequacies of the UK risk-assessment system.
Centre for Occupational and
Environmental Health Policy
De Montfort University