Emerging contaminants in groundwater: occurrence and risk assessment
Stuart, Marianne; Lapworth, Dan. 2011 Emerging contaminants in groundwater: occurrence and risk assessment. [Lecture] In: Priority Substances Monitoring & Occurrence in the Environment. Future Challenges for PBTs in surface & groundwaters, Dublin, Ireland, 20 Sept 2011. (Unpublished)Before downloading, please read NORA policies.
Emerging groundwater contaminants (EGCs) are compounds previously not considered or known to be significant (in terms of distribution and/or concentration) but now being more widely detected. As analytical techniques improve, previously undetected micropollutants are observed. There is a paucity of information regarding EGC occurrence in groundwaters compared to surface waters. The types of organic micropollutants which can be found include, pesticides, pharmaceuticals, caffeine and nicotine and their metabolites, personal care products and fragrances, industrial additives and by-products, food additives , water treatment by-products, flame/fire retardants and surfactants, hormones and nanomaterials. Some have already been defined as Priority Substances, as Hazardous Substances under the Groundwater Regulations or are covered by the Drinking Water Directive. Many others are currently unregulated. Many EGCs are relatively small polar molecules which are not effectively removed by drinking water treatment using GAC. There is a wide variety of sources and pathways for EGCs to enter the environment including both agriculture and urban areas. Key sources include wastewater discharges. Many EGCs can have human or ecological health effects and a better understanding of their fate in environmental systems is needed. To assess the hazards presented by such compounds, information on usage, persistence and leachability, and a robust sensitive analytical method is required. For many pesticides these requirements are fulfilled and an assessment of risk leaching to groundwater can be made. However, for pesticide metabolites such information can be sparse and metabolites assessed as presenting a risk can be derived from less-risky parents. Other compounds, such as pharmaceuticals, cannot as yet be assessed in the same way due to a lack of persistence data; the majority of studies have been directed at water treatment. A literature review for pharmaceuticals, personal care products, lifestyle products and some non-regulated industrial compounds identified the most widely reported compounds detected in groundwater as carbamazepine, sulfamethoxazole, ibuprofen, caffeine and diclofenac. Data interpreted by BGS from the Environment Agency’s monitoring programme for organic pollutants indicates that the 30 most frequently detected or highest concentration compounds comprise both established Priority Substances and emerging compounds, including PAH, petroleum compounds, triazine herbicides, chlorinated solvents, degradation products and THMs, caffeine, DEET and industrial compounds such as nonyl phenol, bisphenol A, BBSA and tributyl phosphate. Hotspots occur for less frequently detected compounds, such as carbamazepine, triclosan and the parabens. The number of regulated contaminants will continue to grow over the next several decades presenting a real challenge for industry, utilities and regulators. There is an ongoing need to prioritise EGCs, it is not possible look for everything everywhere.
|Item Type:||Conference or Workshop Item (Lecture)|
|Programmes:||BGS Programmes 2010 > Groundwater Science|
|Additional Keywords:||GroundwaterBGS, Groundwater, Groundwater quality|
|NORA Subject Terms:||Hydrology
|Date made live:||21 Sep 2011 13:14|
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