Impact of waste water compounds in lake examined

The study of endocrine disruptors in the Okanagan is particularly important because we discharge treated waste water into our drinking water.

The comment by Jeff Curtis, associate professor at UBCO who is leading the research project, was made at the three-day One Watershed—One Water conference that got underway in Kelowna Tuesday.

Endocrine disruptors such as estrogens and other bioactive products are not targeted for removal from waste water during treatment before it is released into Okanagan Lake, so Curtis and his team are investigating the level of such compounds in Okanagan Basin waste waters and waste receiving waters.

The study got underway this September and will involve collection of samples of wastewater from plants in Vernon, Kelowna and Penticton over the next two years.

In the past couple of decades, he said research has found feminization of fish and other aquatic organisms in water with high levels of estrogen. However, he said even small amounts of estrogen can have significant impacts. For instance, very small amounts can cause the collapse of a fish species.

Because the Okanagan has the lowest per capital water supply in Canada, there could be high loading here, and there is also a long residence time for water in Okanagan Lake.

Most waste water in the world is discharged into rivers, not lakes, he noted.

Penticton’s discharge is to the Okanagan River, while in Vernon it’s used to irrigate fields.

There will be differences in the amount of “polishing” of the effluent by the lake, the river or soil, depending on which ecosystem services the discharge, he noted.

Sorption and biodegradation are the primary scavenging mechanisms, and it can take from days to weeks in rivers and soils, he said.

For Vernon’s discharge the time waste water spends in a lagoon and the use of it for spray irrigation provides lots of sorption opportunities, he noted.

In Okanagan Lake, with 60 to 70 years of residence time, you wouldn’t expect to find high concentrations except in deep water where there’s less water movement.

There may be pockets of accumulation, he said. Kelowna, Westbank and Summerland discharge into the big lake.

With Penticton’s discharge into the Okanagan River, he said he wonders about the impacts on kokanee in Skaha Lake.

So far, he said they have developed methods and techniques for their research, and he expects to have the first answers to the simple questions by early next year.

Then, research will turn to the best practices to deal with it and what would happen under different scenarios such as drought or flood.

The research is being funded by the Okanagan Basin Water Board, Health Canada, in conjunction with the Okanagan Indian Band, Interior Health and UBCO.

Curtis was one of 28 speakers on technical topics related to water in the Okanagan Basin Tuesday.

The conference is being put on by the OBWB and the Canadian Water Resources Association at the Capri Hotel. More than 200 delegates have registered.