Canada river 'sweetened' by contaminants

Jan 31, 2014

Spoelstra J, SL Schiff, SJ Brown. 2013. Artificial sweeteners in a large Canadian river reflect human consumption in the watershed. PloS One. DOI: 10.1371/journal.pone.0082706.

Synopsis by Brian Bienkowski

Three artificial sweeteners have been found in a Great Lakes river at the highest concentrations found in surface waters worldwide, according to a new study. The study is one of the first to measure them in a river used for drinking water, and it adds to growing evidence that such compounds are making it past wastewater treatment.

PunchingJudy/flickr

Three artificial sweeteners have been found in a Great Lakes river at the highest concentrations found in surface waters worldwide, according to a new study.

The impact of these sugar substitutes on fish and other aquatic creatures is unknown. The study is one of the first to measure artificial sweeteners in a river used for drinking water, and it adds to growing evidence that such compounds are making it past wastewater treatment.

Twenty-three sites along Canada’s Grand River, which runs through southern Ontario and flows into Lake Erie, were tested for four popular sweeteners: cyclamate, saccharin, sucralose and acesulfame.

“Although concentrations… in the Grand River are small compared to the products they are derived from (e.g. diet drinks), mass fluxes of these compounds to Lake Erie via the Grand River are substantial,” wrote the authors, led by Environment Canada researchers.

The maximum concentrations found for three of the sweeteners – sucralose, cyclamate and saccharin – were 21, 0.88 and 7.2 parts per billion, respectively. They were the highest levels ever reported for those compounds. The fourth, acesulfame, was most consistently detected; it was found in 21 of the 23 sites.

Artificial sweeteners, excreted by people and winding up in sewage, are increasingly showing up in rivers and groundwater around the world. Over the past decade, researchers have found one or more of the four in Sweden, Germany, the United States and Switzerland.

Little is known about how long artificial sweeteners remain in the water and what effects, if any, they have on wildlife. Sucralose does not appear to accumulate in aquatic species.

“We demonstrate here that aquatic organisms likely experience long-term exposure to significant concentrations of [artificial sweeteners] downstream of urban centres that discharge [sewage] effluents,” the authors wrote.

The researchers note that artificial sweetener use is on the rise.

Given its ubiquity, the researchers say acesulfame will “become the most reliable detector of wastewater presence, dilution, and transformation in surface and ground waters.”

Previous research suggests that wastewater treatment plants are more efficient at removing cyclamate and saccharin than acesulfame and sucralose.