EPA - Ireland's Environment, An Integrated Assessment - 2020

Ireland’s Environment – An Integrated Assessment 2020 Microbial contamination of drinking water supplies (by Escherichia coli , enterococci or Cryptosporidium , for example) can arise from human or animal faeces or from water treatment plants that aren’t operating to the standards needed to clean and disinfect water. Poor farm management practices or land spreading of manure close to drinking water abstraction points and private wells can also lead to contamination. The risk to supplies may also be increased as a result of poorly constructed abstraction points and private wells. Additionally, in the case of private wells serving individual houses, disinfection practices may not be in place, which could increase the risk even further. It is well known that the drinking water quality in private water supplies is consistently poorer than that in public water supplies (EPA, 2020d). Private supplies mostly serve rural areas, with the source for most supplies being a spring or a well. While contamination can come from a number of sources, slurry spreading close to the source and animals being allowed to roam too close to the source increase the risk of contamination. This is also a potential source of verocytotoxigenic E. coli (VTEC) contamination – this issue is dealt with in more detail in Chapter 14. Soil Fertility There have been significant improvements in soil pH status in recent years, reversing past trends. Continued emphasis on lime application is required to improve nutrient use efficiency. Efficient production of livestock and crops is a critical first step in ensuring sustainability from both an environmental and an economic standpoint. One important aspect that underpins efficient production is soil fertility. Soil pH plays a key role in soil fertility and maintaining soil pH at the optimum level increases nutrient availability and the microbiological activity of the soil, resulting in better nutrient utilisation. For a number of years there were increasing concerns that soil pH levels were not being kept at their optimum through the regular targeted application of lime. Between 2014 and 2016 only 34 per cent of soil samples were at the optimum pH (Teagasc, 2019b), and between 2017 and 2019 57 per cent of soil samples were at the optimum pH (Teagasc, pers. comm.). National statistics on lime use show that its use declined from 1.7 million tonnes per annum in the 1980s to under 0.9 million tonnes per annum in 2014. However, there has been a growth in the quantities of lime applied to soils in recent years, with 1.04 million tonnes applied in 2018. The quantity of lime applied in 2019 however reduced to approximately 800,000 tonnes. Soil phosphorus and potassium levels also showed a decline in the period between 2007 and 2016 (Teagasc, 2019c), with only 38 per cent of soil samples sufficient in phosphorus and 45 per cent sufficient in potassium for optimal grass and crop production in 2016. Overall, only 10 per cent of soils were at optimum fertility in terms of pH, soil phosphorus and soil potassium. As with pH control, there are some indications that the situation is 338