Review of risk from potential emerging contaminants in UK groundwater

This paper provides a review of the types of emerging organic groundwater contaminants (EGCs) which are beginning to be found in the UK. EGCs are compounds being found in groundwater that were previously not detectable or known to be significant and can come from agricultural, urban and rural point sources. EGCs include nanomaterials, pesticides, pharmaceuticals, industrial compounds, personal care products, fragrances, water treatment by-products, flame retardants and surfactants, as well as caffeine and nicotine. Many are relatively small polar molecules which may not be effectively removed by drinking water treatment. Data from the UK Environment Agency’s groundwater screening programme for organic pollutants found within the 30 most frequently detected compounds a number of EGCs such as pesticide metabolites, caffeine and DEET. Specific determinands frequently detected include pesticides metabolites, pharmaceuticals including carbamazepine and triclosan, nicotine, food additives and alkyl phosphates. This paper discusses the routes by which these compounds enter groundwater, their toxicity and potential risks to drinking water and the environment. It identifies challenges that need to be met to minimise risk to drinking water and ecosystems

A tale of two cities

Across much of Africa, cities are growing quickly. Current projections estimate that by 2050, 60 per cent of the population will be living in urban areas – half of them in slums. Many of these people have little access to services such as clean water and sanitation, and the UN has identified fixing this as a major priority

Technical assistance in Nigeria : developing geoscience skills for tomorrow

The World Bank funded Nigerian Geochemical Mapping Technical Assistance Project was started in 2008 within the Nigerian Ministry of Mines and Steel Development, and is now nearing completion. Staff from the Nigerian Geological Survey Agency (NGSA), the Nigerian academic community, British Geological Survey, and Geological Survey of Finland, have worked alongside one another in a comprehensive program of practical training and knowledge exchange. This program has enabled researchers from a range of backgrounds and experience in Africa and Europe to exchange knowledge and develop important geoscience skills. As part of this program key skills in many areas including; GIS, statistics, QC, data management, laboratory analysis, sampling methodologies, has developed the knowledge and skills base within the Nigerian geosciences community, and has maintained momentum for Nigeria’s national geochemical mapping program. An important objective of the Project is knowledge exchange during training of Nigerian geoscientists in conducting regional geochemical surveys as part of a long term mapping program across Nigeria. Practical training in methodologies for geochemical mapping formed the basis of a major field campaign in 2009, during which over 100 personnel were trained in geochemical mapping techniques. A similar number of personnel were involved in specialist training through a series of workshops and training courses in Nigeria and the UK. Two field areas were selected for the geochemical mapping training — one in central Nigeria (the ‘Minna Cell’) and one in south-western Nigeria (the ‘South-western Cell’) — covering a combined area of 52 000 km2. Key challenges involved the procurement of field equipment and consumables, and modernisation of sample preparation laboratories and archiving facilities at the National Geosciences Research Laboratory, Kaduna. New sample preparation and analytical equipment has been purchased and the laboratory staff have received training in the use of the new equipment. In the long-term it is envisaged that the analytical facilities will be developed further, and that all samples will be prepared, analysed and archived in Nigeria. A national geochemical mapping programme involving multi-element analysis of stream sediment samples is used as a primary dataset in the exploration for new economic mineral deposits. Establishing a geochemical baseline is necessary in order to monitor the effects of anthropogenic activities e.g. contamination caused by industrial waste and mining activities, for environmental investigations and medical geology studies both in rural and in urban areas, as well as studies within the agricultural and forestry sectors

Profiling micro-organic contaminants in groundwater using multi-level piezometers

The presence of micro-organic pollutants, including ‘emerging contaminants’ within groundwater is of increasing interest. Robust protocols are required to minimise the introduction of contamination during the sampling process. Below we discuss the sampling protocols used to reduce inputs of plasticisers during the sampling process, as well as the techniques used to characterise the distribution of micro-organic pollutants in the subsurface. In this study multi-level piezometers installed into the Sherwood Sandstone aquifer in the suburban area of Doncaster, Yorkshire, were used to look at the changes in micropollutants with depth and lithology. Two different methods of pumping groundwaters were employed, and sampling campaigns were undertaken in February and July 2014, under contrasting hydrological conditions

Prioritization Approaches for Substances of Emerging Concern in Groundwater:A Critical Review

Risks from emerging contaminants (ECs) in groundwater to human health and aquatic ecology remain difficult to quantify. The number of ECs potentially found in groundwater presents challenges for regulators and water managers regarding selection for monitoring. This study is the first systematic review of prioritization approaches for selecting ECs that may pose a risk in groundwater. Online databases were searched for prioritization approaches relating to ECs in the aquatic environment using standardized key word search combinations. From a total of 672, 33 studies met the eligibility criteria based primarily on the relevance to prioritizing ECs in groundwater. The review revealed the lack of a groundwater specific contaminant prioritization methodology in spite of widely recognized differences between groundwater and surface water environments with regard to pathways to receptors. The findings highlight a lack of adequate evaluation of methodologies for predicting the likelihood of an EC entering groundwater and knowledge gaps regarding the occurrence and fate of ECs in this environment. The review concludes with a proposal for a prioritization framework for ECs in groundwater monitoring that enables priority lists to be updated as new information becomes available for substances with regard to their usage, physicochemical properties, and hazards

Tracking changes in the occurrence and source of pharmaceuticals within the River Thames, UK: from source to sea

There is a growing interest in the occurrence and sources of pharmaceutical substances in the environment. This paper reports the first detailed transect of pharmaceutical occurrence along the River Thames, UK, from source to sea, undertaken during a period of high flow in 2016. In 37 samples a total of 41 pharmaceuticals and 2 lifestyle compounds (cocaine and sucralose) were detected. Total concentration of pharmaceuticals ranged from 0.0012 µg/l to 10.24 µg/l with a median of 2.6 µg/l. Sucralose concentrations varied from <0.01 to 5.9 µg/l with a median concentration of 1.93 µg/l and was detected in every sample except the groundwater-dominated sources of the Thames. Antimicrobials, including those on the surface water watch list (erythromycin, clarithromycin and azithromycin) were detected in every site downstream of the Thames source. Diclofenac, recently on the surface water watch list, was detected in 97% of Thames samples and above the proposed EQS of 0.1 g/L in 12 samples. Distinct increases in concentration and number of pharmaceuticals were found downstream of the Oxford, Mogdon and Hogsmill wastewater treatment works (WWTW) but were more subdued downstream of the Crossness and Beckton WWTW due to the tidal nature of the Thames and combined sewer outflows. Sucralose was found to be an excellent tracer of wastewaters (treated and untreated) and can be used as a proxy for many pharmaceuticals. Paracetamol and ibuprofen were tracers of untreated wastewater inputs to the Thames due to their high biodegradation within WWTWs

Fingerprinting groundwater pollution in catchments with contrasting contaminant sources using microorganic compounds

Evaluating the occurrence of microorganics helps to understand sources and processes which may be controlling the transport and fate of emerging contaminants (ECs). A study was carried out at the contrasting instrumented environmental observatory sites at Oxford, on the peri-urban floodplain gravel aquifer of the River Thames and Boxford, in the rural valley of the River Lambourn on the chalk aquifer, in Southern England to explore the use of ECs to fingerprint contaminant sources and flow pathways in groundwater. At Oxford compounds were typical of a local waste tip plume (not only plasticisers and solvents but also barbiturates and N,N-diethyl-m-toluamide (DEET)) and of the urban area (plasticisers and mood-enhancing drugs such as carbamazepine). At Boxford the results were different with widespread occurrence of agricultural pesticides, their metabolites and the solvent trichloroethene, as well as plasticisers, caffeine, butylated food additives, DEET, parabens and trace polyaromatic hydrocarbons (PAHs). Groups of compounds used in pharmaceuticals and personal care products of different provenance in the environment could be distinguished, i) historical household and medical waste, ii) long-term household usage persistent in groundwater and iii) current usage and contamination from surface water. Co-contaminant and degradation products can also indicate the likely source of contaminants. A cocktail of contaminants can be used as tracers to provide information on catchment pathways and groundwater/surface water interactions. A prominent feature in this study is the attenuation of many EC compounds in the hyporheic zone

Real-time inference of thermotolerant coliforms in groundwater

Enteric pathogens are typically inferred from the presence of cultured surrogate indicator organisms such as thermotolerant coliforms (TTCs). Their analysis requires suitable laboratories, specialist trained personnel, and is time-consuming, which can limit sampling resolution, particularly during critical pollution events. Tryptophan-like fluorescence has been demonstrated as a useful indicator of human influence on freshwater resources due to its association with sewage and farm waste. Following recent developments in field-deployable optical sensor technology, portable tryptophan-like fluorimeters are now commercially available. We demonstrate their real-time applicability at potable urban groundwater supplies in the developing world. We sampled over 100 supplies for TTCs, and traditional surrogates, such as turbidity and nutrients, as well as tryptophan-like fluorescence. The intensity of tryptophan-like fluorescence was the most effective predictor of the presence/absence and number of TTCs. These sensors have the potential to be included in real-time pollution alert systems for drinking water supplies throughout the world, as well as mapping enteric pathogen risks in developing regions

Geographic distribution of registered packaged water production in Ghana: implications for piped supplies, groundwater management and product transportation

Packaged water consumption has grown rapidly in urban areas of many low‐income and middle‐income countries, but particularly in Ghana. However, the sources of water used by this growing packaged water industry and the implications for water resource management and transport ‐related environmental impacts have not been described. This study aimed to assess the spatial distribution of regulated packaged water production in Ghana, both in relation to demand for natural mineral water and hydrogeological characteristics. A total of 764 addresses for premises licensed to produce packaged water from 2009 to 2015 were mapped and compared to regional sachet water consumption and examined beverage import/export data. We found evidence to suggest that packaged water is transported shorter distances in Ghana than in developed countries. Groundwater abstraction for packaged water is low relative to piped water production and domestic borehole abstraction nationally, but may be locally significant. For natural mineral water, producers should be able to address the most widespread water quality hazards (including high salinity, iron and nitrates) in aquifers used for production through reverse osmosis treatment. In future, packaged water producer surveys could be used to quantify unregulated production, volumes of piped versus groundwater abstracted and treatment processes used