Irish dioxin levels remain well below EU limits, according to the latest assessment by the Environmental Protection Agency (EPA).
Dioxins, which are complex organic compounds released into the atmosphere from fires and other forms of combustion, are mostly insignificant in the levels at which they are encountered.
However, a small number of dioxins are highly toxic, causing a range of ailments from cancer to skin diseases and damage to the reproductive and immune systems.
In Ireland, the most common sources of dioxins are backyard burning of household waste, bonfires, cement kilns, traffic, coal-fired power plants and chlorine bleaching of wood.
However, according to the EPA, levels of dioxins encountered in a survey during the summer of 2006 compared favourably with those from similar studies carried out in the US and Europe.
Some results for the greater Dublin area were higher than elsewhere in Ireland, but remained at less than half the EU limit.
Since most dioxins in Ireland are released into the atmosphere, and settle on grass, samples were taken from milk from cows.
The survey was carried out between late May and early July 2006 by taking milk samples mainly from representative regional dairies.
Additional samples were taken from localities that might be seen as areas of potential risk of raised dioxin levels.
However, the highest level found was less than 50 per cent of the EU limit of 3.0pg WHO TEQ/g for dioxins in milk and milk products.
The survey was repeated in 2007, and early results for the greater Dublin area showed substantially lower levels than in 2006.
Commenting on the results, EPA programme manager Dr Ciaran O'Donnell said: "While some dioxin compounds were found in all samples, as expected, the concentrations were low by international standards."
The survey confirms the continuing low levels of dioxins and dioxin-like PCBs in the Irish environment."
The report, Dioxin Levels in the Irish Environment - Fourth Assessment, is available on the EPA website at http://www.epa.ie/ downloads/pubs/air/quality/
