For quite some years now I have been concerned at the apparent reduction in the number of young native barbel in some of the rivers I fish and of reports that this seems to be fairly commonplace elsewhere. Clubs and fishery owners are regularly stocking to maintain fish populations and in some stretches, where there has been no such action, there seems to be a low density of big fish and very little else. I had read a bit about the environmental concerns regarding the increasing incidence of oestrogen in rivers but the emphasis was mainly on its effect on the sperm count of Londoners who are drinking water that has been ‘recycled’ several times over! 
It wasn’t until a couple of years ago, when I read an article regarding the feminisation of roach in the proximity of sewage outfalls on the River Lea, that I started to wonder to what extent there could be a connection between this phenomena and the poor recruitment of young fish in some of our rivers. With this in mind, I started to read any material I could get hold of on the subject of hormone disruption, much of which is available on the Internet. As I am not a scientist by any stretch, much of it went way over my head but it soon became apparent that organisations such as the Environment Agency and MAFF along with their equivalent bodies in a number of other industrialised countries were expressing concerns in this respect.
1998 saw two important papers published on the subject. The first was a Consultation Paper issued by the EA in February entitled ‘Endocrine disrupting substances in the environment: What should be done?’ and the second a press release from MAFF in November entitled ‘Further Ministry Research on Gender Disruptors’. The Term Endocrine Disrupting Substances (EDS) refers to any substance, whether natural or synthetic, that affects the normal functioning of the hormone (endocrine) system in animals. It was the effect of these chemicals entering our river systems that was attributed with the reproductive changes that were being evidenced in fish and other wildlife.
I have been surprised that, despite the raising of the profile of this problem by the responsible Agencies, there has been so little written about it in the angling press, I guess that serious stories don’t sell copy! Also how few of the anglers to whom I have spoken know of the problem and its potentially disastrous effect on future fish stocks. What I hope to do in writing this article is to increase awareness of the issue and, hopefully, to encourage at least some of you to find out about EDS and to support the EA in their moves to put pressure on the Water Companies waste management operators and those Industries that contribute to the problem. This is not intended to be a detailed scientific paper as I am in no way qualified to produce such a document and I have, therefore, listed a number of source documents that are readily available if you want to find out more. 
The EA’s Strategy has only recently been published some 2 years after the Consultation document was issued and in it they refer in it to having received over 60 responses. This document is entitled ‘Endocrine-disrupting substances in the environment: The Environment Agency’s strategy’ and is readily available from the EA at no cost or can be downloaded from their website www.environment-agency.gov.uk. I would suggest that every serious angler should be aware of this document and its content.
Basically there are two distinct categories of EDS. The first are those that are naturally occurring, such as the natural estrogens that are present in plants (phytoestrogens). In the main these are not considered to be a problem as they have always existed. However, some concern has been expressed in relation to industrial or agricultural processes that discharge vegetable waste matter in large quantity, especially where the receiving watercourse has a low flow rate (possibly due to abstraction). It is also not known whether these natural substances can interact with the second group of EDS to produce physiological abnormalities in fish and other wildlife.
The second category of EDS are those that arise from the activity of man and these are by far the greatest concern. Within this group there are several types; those introduced intentionally such as pesticides, the by products of industrial processes or waste disposal and those contained and produced in wastewater treatment and discharge. This article is too short to list the full range of these chemicals but they are set out in detail in the Consultation paper with a description of any current measures that are in place to control the quantity of such substances released into the environment. The paper also describes the system of Environmental Quality Standards (EQS) that applies to some but by no means all of these substances.
As far as I am concerned, the most interesting of the potentially hormone disrupting substances entering our rivers are those emanating from sewage treatment as this appears to be the major source of Eostrogens (feminising steroids) and to a lesser extent Androgens (masculinising steroids). Sewage treatment plants also produce a cocktail of other potentially EDS substances which may or may not interact to produce hormonal changes and abnormalities such as growth rate.
Put simply, steroids are naturally excreted by humans in an inactive form but they become re-activated by the sewage treatment process. Clearly the increased use of synthetic steroids for contraception has greatly increased the volume of certain chemicals in sewage particularly eostrogens and it is these that appear to effect fish. In addition, there are a range of other chemicals that have been identified as either mimicking or blocking the effects of natural eostrogens and these are also present in treated effluent.It appears to be acknowledged by all concerned that current knowledge and understanding of the effects of such steroids and ‘false’ steroids is somewhat lacking. However, there is an increasing acceptance that feminisation of fish is linked to effluent discharge and that it is significantly greater downstream of discharge points. This must be a concern to us as anglers and conservationists. The EA have actually made the statement that ‘Steroids are a group of chemicals that present particular challenges because:
1.They are likely to be present in all sewage effluents
2.Some are naturally produced and sources are not readily controllable
3.They are biologically active at very low concentrations’
The Environment Agency Strategy deals with the full range of EDS issues but I will only summarise here that which relates specifically to sewage Treatment and Steroid effects.
From the outset, the EA has stated that its approach towards environmental protection is based on prevention rather than cure and this can be summarised as:
