Abstracts

Artificial sweeteners (AS) are commonly used in food, beverage and medicinal products,
largely to reduce sugar consumption. Several of these artificial sweeteners are not completely
broken down during wastewater treatment and are increasingly being found in
lakes, rivers, and groundwater around the world. In urban areas, municipal wastewater
treatment plants and leaky sewer systems can be a source of artificial sweeteners to local
groundwater and surface water. In rural areas, private septic systems treat domestic wastewater
and discharge effluent to the sub-surface, making them a primary source of AS in
rural groundwater. Landfill leachate may also be a source of AS in both settings.
To investigate the prevalence of artificial sweeteners in rural groundwater, we sampled
private domestic wells and groundwater springs in the Nottawasaga River Watershed
(NRW), located about 50 km north of Toronto, Ontario, Canada. Domestic groundwater
in the southern NRW is typically supplied by the Lake Algonquin Sand Aquifer (LASA),
a sandy surficial aquifer known to have nitrate concentrations of up to ten times the drinking
water limit. The LASA is exposed along the incised banks of the southern Nottawasaga
River and groundwater discharge was sampled from these seeps.
Four AS, acesulfame (ACE), cyclamate (CYC), saccharin (SAC), and sucralose (SUC)
were analyzed using ion chromatography coupled with tandem mass spectrometry operated
in negative electrospray ionization mode, with minimum detection limits ranging from
2 to 20 ng/L for the individual AS. ACE was the most frequently detected AS in groundwater
and had the highest measured concentration (>26,400 ng/L). Artificial sweeteners
were detected in 31% and 37% of the domestic wells and groundwater seeps, respectively,
indicating a contribution of water derived from septic system effluents. No clear relationships
were found between the presence of artificial sweeteners and the concentrations of
other groundwater contaminants potentially derived from septic systems, including nitrate,
ammonium, and soluble reactive phosphorus.
The persistence, mobility, and relatively high concentrations of AS in the environment,
particularly ACE, means that these compounds may still be detectable in groundwater
long after other wastewater constituents (e.g. nutrients, pharmaceuticals, pathogens) have
been removed or diluted to levels below detection limits. Artificial sweeteners have the
potential to be a powerful groundwater screening tool for identifying wells or aquifers that
have a septic effluent component to recharge and where testing for additional contaminants
may be warranted, especially where the groundwater is used for potable water supply
or discharges to environmentally sensitive surface waters.
217 - Hydrogeological characterization of a waste site at Chalk
River, Ontario
Colleen Steele, Grant Ferguson & Andrew Ireson
Department of Civil and Geological Engineering – University of Saskatchewan, Saskatoon,
Saskatchewan, Canada
Geological storage of low level radioactive waste presents a substantial challenge. Waste at
these sites can remain radioactive for hundreds of years. These sites frequently contain other
104 IAH-CNC 2015 WATERLOO CONFERENCE