Researchers have determined that the presence of artificial sweeteners in rural groundwater is evidence of local septic system wastewater contamination.

Publishing their findings in the Journal of Environmental Quality, the research team from the University of Waterloo detail how they tested for the presence of four different artificial sweeteners in private, rural Nottawasaga River watershed groundwater wells in an effort to identify groundwater contamination by human wastewater from nearby septic systems.

An ideal tracer for human wastewater because they pass through the body virtually unchanged, artificial sweeteners cannot be completely removed by most wastewater treatment systems.

"Although the four artificial sweeteners we measured are all approved for human consumption by Health Canada, it is the other septic contaminants that might also be present in the water that could pose a health risk," said John Spoelstra, first author on the study and an adjunct professor in earth and environmental sciences at Waterloo. "As for groundwater entering rivers and lakes, the effect of artificial sweeteners on most aquatic organisms is unknown."

Researchers found that over 30 percent of the samples from almost 60 private wells had traces of at least one of the four artificial sweeteners.

Likewise, the team also tested groundwater from the banks of the Nottawasaga River where 32 percent of the team's samples tested positive for artificial sweeteners, an indicator that some of the groundwater seeping into the river is septic system run-off.

"We were not really surprised by the most recent results given what we've found in past studies," said Spoelstra, also a Research Scientist with Environment and Climate Change Canada. "Septic systems are designed to discharge effluent to groundwater as part of the wastewater treatment process. Therefore, contamination of the shallow groundwater is a common problem when it comes to septic systems."