Dr. Eimear Cotter:

I thank the Senator for that intervention. Scientific integrity is at the heart of what we are doing. The interim assessment we have produced is according to criteria set down by the Commission. There are four tests, which we can talk through in more detail. They are published in the Commission implementing decision, which was published last year. They were agreed between the Department of Agriculture, Food and the Marine, and the Commission as part of securing our derogation. Those are the criteria we followed to produce this interim review. The data underpinning this interim review come from a subset of our total national monitoring network. That network has been used to report under the nitrates directive since 1991. The sites, the design and the distribution of that subset of the total national network are in place in order that we pick up the impact of agriculture on water quality. That is as required by the nitrates directive. We see the impact of urban wastewater when we are looking at our total national water quality monitoring network. We report on the impact of wastewater on water bodies. They are impacting on approximately 200 water bodies.

For the purpose of this interim assessment, following the criteria set out by the Commission we are using the subset, which is a smaller network of 200 to 300 monitoring points. The time is also prescribed by the Commission. We were asked to look at the difference between 2021 and 2022. We have followed faithfully what has been prescribed by the Commission. As I have said, all of the data have been published and can be interrogated. Looking at the longer term trend, we are seeing that nitrate levels have increased since 2013 to a level that is now too high to support good water quality. We are seeing that in particular in the south and south east of the country. Nitrate levels are too high in 40% of rivers in the country . We bring together vast amounts of data in our assessment and analysis. When we start in the river, estuary or lake, we take a measurement. We analyse that sample in our laboratory. We see whether there is nitrate or phosphorous, and then we start working back to see what is happening in the area around that water body. What are the populations? What are the numbers and locations of septic tanks? Are there wastewater treatment plants? What is the level of treatment in those plants? What is the number of animals, their excretion rates and the soil type? We look at forestry and industry. We look at all of that information and use models that have been developed over many years, published and peer-reviewed to determine the source of the nutrient we are seeing in the water.

That is an assessment we do and we are then able to see where the main pressures are on our water bodies. We know that agriculture impacts 1,000 water bodies in the country. After that, it is physical modifications, such as drainage and channelisation, as well as wastewater, impacting about 200 water bodies in the country. We publish all that. We have charts that show the different pressures that we can make available to this committee if it would be helpful.

I think I covered most of the points.