Emerging contaminants in groundwater - NERC Open Research ...

OR/11/013
1 Introduction
Increasingly sensitive analytical techniques have detected the presence of previously
unregulated organic micropollutants in actual or potential sources of drinking water
worldwide. The term ‘emerging contaminants’ is generally used to refer to such compounds
often previously not considered or known to be significant to groundwater (in terms of
distribution and/or concentration) but which are now being more widely detected.
This report provides a review of organic micropollutants which can be found in the aqueous
environment, which are or could have the potential to become emerging contaminants. A
source-pathway-receptor approach has been used to evaluate the possible important
compounds, their persistence and the routes by which they enter groundwater. Sources could
include newly identified compounds from well-studied issues, such as pesticide metabolites.
Other compounds such as agricultural feed additives have been little studied in groundwater
but travel by well-studied pathways. A significant pathway factor related to emerging
contaminants is the degree to which they are removed by current drinking water treatments.
The main receptor factors considered here are the hazards to humans if these contaminants
enter drinking water supplies.
As well as pesticides, types of organic micropollutants can include pharmaceuticals, personal
care products, hormones and a wide range of industrial chemicals and intermediates. These
types are discussed in Chapter 3. Some of these contaminants can have human or ecological
health effects and there is a need for better understanding of their fate in environmental
systems.
Pesticides and their metabolites are probably the most studied group of emerging
contaminants. The mechanisms of pesticide transport to groundwater are discussed in
Chapter 4. The properties of most pesticides and their metabolites currently licensed in the
UK have been assessed to identify other potential problems. Our approach highlights those
compounds most likely to persist in the aqueous environment, and those which may evade
current water treatment practices.
Persistence of other pollutants, particularly pharmaceuticals, is less-well characterised and
these are assessed using literature case studies to indicate the compounds which have been
identified in groundwater and possible concentrations. These are grouped into those
compounds which are derived primarily from urban and industrial sources (Chapter 5) and
veterinary medicines (Chapter 6).
Published data for emerging contaminants in groundwater of the UK are sparse. We have
processed and summarised a large set of analyses collected by the EA on organic
micropollutants in groundwater from England and Wales. The results of this work are
reported in Chapter 7.
The UK regulatory setting for organic micropollutants in aquifers and drinking water is
summarised. It is likely that regulation will be extended over the coming decades to cover
more of the emerging contaminants.
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