Bruce D. R. Misstear

Sacred wells and springs are important cultural features in many societies. A recent study in Ireland may be the first detailed countrywide investigation of the hydrogeology and water chemistry of sacred wells. Key findings are discussed in relation to case studies elsewhere. A wide range of hydrogeological settings are represented. There is evidence of anthropogenic impacts at many sacred springs and wells. Communication of potential health impacts is necessary but challenging, because of the sensitivities surrounding these sacred water sources.

An assessment of global groundwater quality is needed in response to the threats posed by anthropogenic and geogenic contaminants. This essay summarises the challenges involved, including a large number of potentially relevant water quality parameters, the poor availability of data in many regions and the complex nature of groundwater systems. Direct monitoring data can sometimes be augmented by indirect methods such as earth observations, and by involving citizen science. A new web portal is being developed to complement existing databases.

Traffic is a major source of urban air pollution that affects health, especially among children. As lower speed limits are commonly applied near schools in many cities, and different governments have different policies on vehicle fleet composition, this research estimated how different speed limits and fleet emissions affect air quality near a primary school. Based on data of traffic, weather, and background air quality records in Dublin from 2013, traffic, emission, and dispersion models were developed to assess the impact of different speed limits and fleet composition changes against current conditions. Outside the school, hypothetical speed limit changes from 30 km/h to 50 km/h could reduce the concentration of NO₂ and PM₁₀ by 3% and 2%; shifts in the fleet from diesel to petrol vehicles could reduce these pollutants by 4% and 3% but would increase the traffic-induced concentrations of CO and Benzene by 63% and 35%. These changes had significantly larger impacts on air quality on streets with higher pollutant concentrations. Findings suggest that both road safety and air quality should be considered when determining speed limits. Furthermore, fleet composition has different impacts on different pollutants and there are no clear benefits associated with incentivising either diesel or petrol engine vehicles.

Ptaquiloside, along with other natural phytotoxins, is receiving increased attention from scientists and land use managers. There is an urgent need to increase empirical evidence to understand the scale of phytotoxin mobilisation and potential to enter into the environment. In this study the risk of ptaquiloside to drinking water was assessed by quantifying ptaquiloside in the receiving waters at three drinking water abstraction sites across Ireland and in bracken fronds surrounding the abstraction sites. We also investigated the impact of different management regimes (spraying, cutting and rolling) on ptaquiloside concentrations at plot-scale in six locations in Northern Ireland, UK. Ptaquiloside concentrations were determined using recent advances in the use of LC-MS for the detection and quantification of ptaquiloside. The results indicate that ptaquiloside is present in bracken stands surrounding drinking water abstractions in Ireland, and ptaquiloside concentrations were also observed in the receiving waters. Furthermore, spraying was found to be the most effective bracken management regime observed in terms of reducing ptaquiloside load. Increased awareness is vital on the implications of managing land with extensive bracken stands.

The specific aims of this paper are to: (i) quantify the effects of various long range transport pathways nitrogen dioxide (NO₂) and particulate matter with diameter less than 10μm (PM₁₀) concentrations in Ireland and identify air mass movement corridors which may lead to incidences poor air quality for application in forecasting; (ii) compare the effects of such pathways at various sites; (iii) assess pathways associated with a period of decreased air quality in Ireland. The origin of and the regions traversed by an air mass 96h prior to reaching a receptor is modelled and k-means clustering is applied to create air-mass groups. Significant differences in air pollution levels were found between air mass cluster types at urban and rural sites. It was found that easterly or recirculated air masses lead to higher NO₂ and PM₁₀ levels with average NO₂ levels varying between 124% and 239% of the seasonal mean and average PM₁₀ levels varying between 103% and 199% of the seasonal mean at urban and rural sites. Easterly air masses are more frequent during winter months leading to higher overall concentrations. The span in relative concentrations between air mass clusters is highest at the rural site indicating that regional factors are controlling concentration levels. The methods used in this paper could be applied to assist in modelling and forecasting air quality based on long range transport pathways and forecast meteorology without the requirement for detailed emissions data over a large regional domain or the use of computationally demanding modelling techniques.

One of the key threats to groundwater and surface water quality in Ireland is the impact of poorly designed, constructed or maintained on-site wastewater treatment systems. An extensive study was carried out to quantify the impact of existing sites on water quality. Six existing sites, consisting of a traditional septic tank and soakaway system, located in various ranges of subsoil permeabilities were identified and monitored to determine how well they function under varying subsoil and weather conditions. The preliminary results of the chemical and microbiological pollutant attenuation in the subsoil of the systems have been assessed and treatment performance evaluated, as well as impact on local surface water and groundwater quality. The source of any faecal contamination detected in groundwater, nearby surface water and effluent samples was confirmed by microbial source tracking. From this, it can be seen that the transport and treatment of percolate vary greatly depending on the permeability and composition of the subsoil.

Based on the sampling of 262 private domestic wells in Ireland, mainly located in High/Extreme vulnerability areas, a quantitative model was developed for prediction of gastrointestinal infection risk attributable to verotoxigenic E. coli (VTEC) contamination of private wells in Ireland. Models are based on maximum likelihoods and predict an overall crude incidence rate of 28.3/100,000 well users per annum; approximately 5-6 times higher than crude incidence rates reported within the Irish population and up to 40 times higher than the current EU mean. Predicted crude incidence rates (CIR) of 21.6/100,000 and 88.7/100,000 were associated with borehole and hand-dug wells users, respectively, with predicted annual probabilities of 0.1% and 0.17%, respectively. Predicted annual infection risks associated with both (untreated) well types exceed the USEPA acceptable target of <1 infection/10,000 consumers/year. Where treatment systems are employed, models predict that a relatively small pathogen log reduction is necessary to meet health targets. Sensitivity analyses indicate that pathogen loading and dose-response are the input variables with the greatest contribution to model outputs. Using a more conservative assumption for pathogen contribution ratio, models predict a lower annual CIR of 5.56/100,000. Due to limitations in inherent assumptions, model results, while useful, should be treated with caution.