A comprehensive research project has begun to investigate if chemicals that disrupt the body's normal hormone balance are present in the State's fresh water systems.
The chemicals have the potential to disturb vital human regulatory systems related to normal growth, sexual development and reproduction.
Cork Institute of Technology (CIT) will administer the project. Scientists will search rivers and lakes for man-made and naturally occurring chemicals known as endocrine disrupting compounds (EDCs). These chemicals interfere with the endocrine system, a hormone control network in humans and animals that co-ordinates all fundamental life functions, including regulation of growth, sexual development and reproduction.
If they find EDCs, the researchers will also analyse the chemicals' effect on aquatic life, especially fish populations, explained Dr Heloise Tarrant, lecturer in CIT's School of Biological Science, and also the project's administrator.
An increasing number of EDCs, and their by-products are throwing the endocrine systems of a number of different species off balance, leading to what some have termed the "feminisation of nature".
In this scenario male creatures begin to exhibit female characteristics, reducing fertility and possibly threatening the species' long-term future. Some male fish, for example, have begun to express a protein previously specific to females.
EDCs have been an intensively-studied topic in scientific research for the past 10 years, with the main focus on the chemicals' effect on the reproductive system.
Trends have revealed a fall in reproductive success rates in animals and fish and a rise in the amount of EDCs in the environment, Dr Tarrant said. Scientists have uncovered "strong evidence" for a link between the two trends, and are currently "trying to establish a definite link between the trends and the existence of various environmental chemicals", she said.
The Cork scientists will search for potential EDCs, which have the ability to interfere with the body's production of oestrogen, the female sex hormone.
Some chemicals could activate this hormone's production, while others could de-activate it, Dr Tarrant explained. She said other EDCs operate in the reverse direction, with female fish developing male characteristics.
This research project, undertaken in partnership with University College Cork and the Centre for Ecology and Hydrology in the UK, will assess whether there is a risk from these chemicals in the State's aquatic environment.
EDCs come from several sources including some fungicides, herbicides, and insecticides; compounds found in batteries, paints and petrol; industrial detergents, plasticisers; as well as waste from pulp, paper and textile industries.
Sewage treatment effluent may also contain high concentrations of natural human hormones. This has been found to be a major source of EDCs in the UK.
The two-year project, funded by the Environmental Protection Agency (EPA), will search for EDCs using a number of scientific approaches. Waste water from sewage treatment works, industrial and agricultural sites will be chemically analysed. Samples will also be tested in a laboratory to see if chemical compounds present might have any significant effect on the endocrine system.
Biological tests will also take place in the natural environment. The effects of effluent from sewage treatment works on fish will be analysed, and wild fish will be studied to determine whether they are carrying EDCs.
The scientists hope the findings will allow the Government, industry and public bodies to take preventative measures as necessary to protect the environment. Only freshwater systems will be analysed in the CIT study, most of them in the south.
The project is modelled on similar studies in the UK, which found nearly all rivers have been affected by EDCs.
There are differences however between the UK and Ireland in relation to EDCs, Dr Tarrant explained. A higher population density, for example, means there is a greater volume of sewage dumped in rivers, possibly leading to a greater amount of EDCs. The research report is due in two years.
dfahy@irish-times.ie