Pesticides and metabolites in groundwater: examples from two major UK aquifers

Reducing the impact of anthropogenic pollution on groundwater bodies and ameliorating any deterioration of water quality is central to key legislative drivers such as the EU Water Framework Directive and the proposed daughter Directive relating to the protection of groundwater. Pesticide pollution has a direct impact on groundwater quality and an indirect impact on the associated aquatic ecosystems supported by groundwater. There is currently no legislative requirement to monitor pesticide metabolite concentrations in groundwater. Pesticide and metabolite results from two nationally important aquifers are presented, the Trassic Sandstone and the Chalk of Southern England. Aerobic microbial degradation of diuron in the soil can lead to the formation of three compounds; dichlorophenylmethyl urea (DCPMU), dichlorophenyl urea (DCPU) and dichloroanaline (DCA).Median diuron concentrations were significantly higher than each of the metabolites with outliers exceeding the PVC on at least one occasion. At nine sites in Kent, Southern England, (60%) metabolites were more prevalent than diuron. Both aquifers are an important source of water, locally supplying up to 80% of public drinking water. The sandstone site has a predominantly arable landuse with a potential diffuse source of pesticides although soakaways are possible point sources.The chalk site has a mixture of arable and industrial/urban landuse. A significant source has been from excessive applications of diuron (“over-spray”) on a number of public amenities. Data from both aquifers show that pesticide concentrations have a high degree of temporal variability. Elevated pesticide concentrations are associated with recharge events in both aquifer systems regardless of pesticide source terms. Pesticides from amenity use and diffuse agricultural sources both pose a threat to groundwater quality. Pesticide metabolites are present in significant concentrations in groundwaters. Systematic, long-term monitoring (5-10 years) is required to understand trends in groundwater quality

Scotland's groundwater monitoring network : its effectiveness for monitoring nitrate

Scotland has had a national groundwater quality monitoring network since the year 2000. One of the main functions of this network is to monitor nitrate concentrations. Nitrate can be elevated in the environment due to modern agricultural practice. Initially there were 150 monitoring sites, but these have been added to, and in 2005, the number of groundwater monitoring points for nitrate was 219, comprising 139 boreholes, 51 springs and 27 wells; 67% of these sites are in agricultural areas. In order to have confidence in the interpretation of data gathered from the network it is important to know the context of the sample points, and in particular whether any sites are compromised by surface contamination or nearby point sources. Prior to this study, many of the sites had not undergone a formal risk assessment and their condition was unclear. In order to improve confidence in the network, and to help act as a baseline before improving the network, the British Geological Survey and the Macaulay Institute were commissioned by the Scottish Executive to carry out a review during the period February-July 2005. The core of the project was to undertake field assessments for 151 sites where no formal assessment had been made previously. Using criteria developed in this project, a judgement was made as to whether the monitoring point was adequate, required improvement or further assessment, or should be considered for removal. For all 219 sites on the network, a zone of influence was estimated using a semi-quantitative method. These zones were used to help focus the field surveys and also to characterise each site using national datasets; for example the monitoring site would be assigned the land use that occupied more than 60% of the zone. These data were then used to conduct an analysis of the factors controlling nitrate concentrations across the network and to help evaluate how effective the network is at monitoring nitrate in Scottish groundwater. Below is a summary of the main results from the project: 1. The fieldwork and analysis of the 151 previously unassessed sites indicated that: • 61 of the 151 sites are adequate and can continue to be monitored with no improvements. • There are serious concerns about 29 of the 151 sites (19% of the sites assessed and 13% of the total nitrate network). These sites should be considered for removal from the network. The sources found to be least reliable were shallow large diameter wells. However, there is little evidence to suggest that the data from these sources collected from 2000 – 2005 has been seriously compromised by point source pollution. • 30 sites require further assessment before being judged suitable. Most of these sites are springs and require additional work to identify the precise source. • 31 sites require improvements to the monitoring points – the improvements range from better sampling protocols to improving the headworks through simple engineering. 2. There is a clear difference between nitrate concentrations measured in the areas designated as nitrate vulnerable zones (NVZs) and other areas. Within the NVZs, the mean concentration is 25 mg-NO3 l-1 and the median 17 mg-NO3 l-1; outside the NVZs, the mean concentration is 9 mg-NO3 l-1 and the median 4.4 mg-NO3 l-1. The data from the network indicate that land use has a large influence on the nitrate concentrations measured in the monitoring network: arable areas, mixed cultivation of both arable and grassland, and areas where dairy, pigs and poultry are reared contribute to the highest nitrate concentrations, with 18% of sites in these areas exceeding 50 mg-NO3 l-1. The most significant control on nitrate concentrations in the monitoring network is the presence of dairy, pigs or poultry within the zone of influence. 4. A considerable number of monitoring sites have lower nitrate concentrations than would be expected from the nitrate pressure. This can be attributed to dilution from rainfall, mixing with older low nitrate waters, denitrification, or the presence of low permeability soil and superficial deposits which slow the movement of high nitrate water into the aquifers. 5. A “gaps” analysis which compared the current network with an idealised network based on nitrate pressures across Scotland indicated that overall the distribution of the current network is generally good. However, there are significant gaps in the improved grassland areas of the Midland Valley and Ayrshire and in the arable areas of Aberdeenshire, while Mid and East Lothian and the Borders are currently overrepresented. The following recommendations are made for the nitrate groundwater quality network in Scotland: 1. Consideration should be given to removing or replacing 29 of the 219 sites, and undertaking further assessments on 30 sites. A further 31 sites would benefit from improvements to the headworks or sampling arrangements. 2. Further statistical analysis should be undertaken to help understand the factors that control the nitrate concentrations in groundwater – particularly the environmental factors that help to reduce the measured nitrate. 3. The network should continue to be concentrated on nitrate pressured areas in Scotland, with approximately 75% of the network in high nitrate areas, and 25% used to monitor background nitrate concentrations in less pressured areas. 4. Any future sites added to the network must undergo a risk assessment similar to the one developed for this study to ensure that the network remains of good quality. 5. The network must continue to reflect the diverse hydrogeological, soil and land use conditions in Scotland. Therefore, both bedrock and superficial aquifers should be monitored in a variety of soil conditions. The network should continue to include different types of sources, although less emphasis should be given to wells, which are generally poor monitoring points. 6. In the future, the data from the network will require to be actively interpreted: an inevitable outcome from having a diverse network is that the results of the monitoring must be interpreted not only in terms of agricultural practice, but in light of the other factors such as geological and environmental conditions. In practice this could mean a regular detailed review (maybe every 2-3 years) of the data from the network. 7. The network will also need to be actively managed to account for various changes in monitoring sites, for example the land use, the condition of the headworks and the pumping rate. This will involve SEPA hydrogeologists having an overview of the network; individual sources being periodically reviewed using a simple checklist; and additional new sources being sought, possibly through the ongoing BGS/SEPA study of baseline groundwater chemistry across Scotland. 8. Wellhead measurements should be taken periodically to help identify denitrification or mixing with older waters. The limited samples taken during this study proved invaluable for interpreting apparently anomalous nitrate concentrations. To undertake this successfully, dedicated sample taps may have to be introduced. 9. A separate programme of focussed monitoring should be developed in tandem with the national groundwater monitoring network to give information on the effects of the action programmes within the NVZs. These sites should be in a controlled environment that will respond rapidly to changes in agricultural practice. The results from these studies can then be upscaled to help interpret changes in the national network as well as be used on their own to help understand the success of the Action Programmes

A hidden crisis: strengthening the evidence base on the sustainability of rural groundwater supplies: results from a pilot study in Uganda

Extending and sustaining access to rural water supplies remains central to improving the health and livelihoods of poor people, particularly women, in Africa, where 400 million rural inhabitants have no form of utility provided water, and universal access to water hinges on accelerated development of groundwater (UN 2013). The ‘future proofing’ of groundwater investments is therefore vital, especially in the context of global and local trends including demographic shifts, environmental impacts of human activity and climate change (Taylor et al. 2013). The emphasis, in recent years, on accelerating access to new infrastructure has obscured a hidden crisis of failure. More than 30% of sources are non‐functional within a few years of construction (Rietveld et al. 2009, RWSN 2009, Lockwood et al. 2011) and a greater number are seasonal (for example 50% in Sierra Leone) (MoEWR 2012). The accumulated costs to governments, donors, and, above all, rural people, are enormous. The original benefits generated by the new infrastructure – improved health, nutrition, time savings, education, particularly for the poorest – are lost if improved services cannot be sustained. The cumulative effect of rural water supply failure in Africa over the past 20 years has been estimated by the World Bank to represent a lost investment in excess of $1.2 billion. Critically, there is limited data or analysis on why sources are non‐functional and therefore little opportunity to learn from past mistakes. This report provides a summary of the work undertaken by the UK‐funded UPGro research programme ('Unlocking the Potential for Groundwater for the Poor') for sub‐Saharan Africa (SSA) funded by the Natural Environment Research Council (NERC), the Economic and Social Research Council (ESRC) and the Department for International Development (DfID). The Catalyst Grant project ‘A Hidden Crisis’ was aimed at developing a methodology and toolbox to investigate the causes of failure in groundwater‐based water services in SSA, which could form the foundation for more substantial and larger‐scale research in the future to develop a statistically significant evidence base to examine water point functionality and the underlying causes of failure across a range of physical, social, institutional and governance environments in SSA. To test the toolbox and methodology developed, a pilot study was conducted in northeast Uganda Overall, the approach and methods developed in the catalyst project have been shown to make a significant step towards developing a replicable and robust methodology which can be used to generate a systematic evidence base for supply failure. The work has gone a significant way to encapsulating the complexity of the interlinked aspects of the problem, balancing the natural science and engineering (“technical”) aspects of the research with those concerning the ability of communities to manage and maintain their water points (the “social” aspects). The multiplicity of interlinked causes of water point failure was explicitly acknowledged and taken into account through the use of multi‐disciplinary field and analytical methods within the toolbox and in selection of the research team. The multi‐disciplinary methods of investigation used were highly practical and appropriate to the information sought, and based on detailed observational science

Assessing pesticide pollution of groundwater: current knowledge and remaining gaps

This paper summarises recent research on pesticides in groundwater in both temperate and tropical regions. Results of field, laboratory and modelling studies highlight the factors which determine the fate and behaviour of pesticides in groundwater systems. These include transport pathways from the soil to the water table and thence to supply sources, and the processes such as adsorption and degradation which can help to attenuate pesticide movement and reduce concentrations. Studies of degradation show that most compounds are likely to be much more persistent in aquifers than in soils, but below the water table the long travel times and potential for dilution may greatly reduce concentrations. The greatest risks are likely to occur in fractured aquifers with their potential for much more rapid flow. Important uncertainties and gaps in knowledge remain. Laboratory studies of degradation present difficulties of extrapolation to field conditions and provide evidence of wide variations in half-lives spatially and with time; making the choice of values for transport modelling problematic. Further work is required to improve understanding of such variations. Studies can also indicate that different degradation pathways can occur and different pesticide metabolites produced, depending onenvironmental conditions. The occurrence and behaviour of metabolites in groundwater systems is also poorly known

A hidden crisis: strengthening the evidence base on the current failure of rural groundwater supplies

New ambitious international goals for universal access to safe drinking water depend critically on the ability of development partners to accelerate and sustain access to groundwater. However, available evidence (albeit fragmented and methodologically unclear) indicates >30% of new groundwater-based supplies are non-functional within a few years of construction. Critically, in the absence of a significant systematic evidence base or analysis on supply failures, there is little opportunity to learn from past mistakes, to ensure more sustainable services can be developed in the future. This work presents a new and robust methodology for investigating the causes of non-functionality, developed by an interdisciplinary team as part of a UK-funded development research project. The approach was successfully piloted within a test study in NE Uganda, and forms a basis for future research to develop a statistically significant systematic evidence base to unravel the underlying causes of failur

A hidden crisis: strengthening the evidence base on the current failures of rural groundwater supplies

New ambitious international goals for universal access to safe drinking water depend critically on the ability of development partners to accelerate and sustain access to groundwater. However, available evidence (albeit fragmented and methodologically unclear) indicates >30% of new groundwater-based supplies are non-functional within a few years of construction. Critically, in the absence of a significant systematic evidence base or analysis on supply failures, there is little opportunity to learn from past mistakes, to ensure more sustainable services can be developed in the future. This work presents a new and robust methodology for investigating the causes of non-functionality, developed by an interdisciplinary team as part of an UPGro catalyst grant. The approach was successfully piloted within a test study in NE Uganda, and forms a basis for future research to develop a statistically significant systematic evidence base to unravel the underlying causes of failure

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter