Dishwasher soap a phosphate contributor


During the recent Clean Streams presentation the fact was mentioned that our lake, Oswego Lake, was high in phosphates. This was the reason for the Lake Corporation applying the large amounts of copper sulfate to the lake, a highly toxic plant, fish and (surface) animal poison. The connection is that typically, and the lake is typical in this regard, algae have all the nutrients required, primarily carbon, but lack the tiny amount of phosphate to grow in abundance. And when the algae grow in abundance the result can be a 'bloom,' which can kill other plants and fish, oxygen depletion and hydrogen sulfide odors. The water is discolored and can be harmful to swimmers. The amount of phosphate in the lake exceeds the limits of the federal guidelines. The copper sulfate kills the algae, as well as everything else, but does not reduce the amount of phosphate in the water.

Other communities, cities and states have wrestled with this problem. Typically, while phosphate in fertilizers is definitely an issue and restricting use in our city is warranted and necessary, the main source is from detergents. Some years ago phosphates in laundry detergent were eliminated but, unlike the restrictions in Canada, phosphates in dishwasher detergents have not been eliminated. Mentioned in the Clean Streams presentation is the fact that the pipes leading to the interceptor sewer line allow incursion so that during rainstorms the increase in volume to the sewer treatment facility is three-fold. It is not hard to figure that phosphates, noted for their surfactant (wetting) properties, will exude from the same pipe openings and get into the runoff to the lake.

Also mentioned in the presentation was the fact that a highly effective, economical and low-risk approach to preventing incursion and excursion from pipes such as these is to line them with a plastic sheath by accessing them every thousand feet or so and forcing the sheath into the pipe. In some cases the sheath is essentially glued to the wall of the pipe to strengthen it. This may or may not be done, it was only mentioned in passing as an effective means to prevent incursion but it would address several problems, including escape of phosphates, and could eliminate the need for the interceptor project if effective enough. In the interim, the need is to eliminate the widespread use of phosphate dishwasher detergents in Lake Oswego drainage basins.

The citizen input at the presentation was consistent in all present suggesting that people should be informed of the need and the methods for controlling the phosphate issue. Dishwasher detergent is widely available, at all grocery stores that I checked in Lake Oswego, that contains no phosphates. Because of enzyme action, it is just as effective at cleaning. Seventh Generation is one brand available almost everywhere and by my tests is every bit as good as Cascade or any other phosphate-containing brand. Consumer Reports and other studies indicate effective cleaning with no-phosphate brands from Costco, Fred Meyer and Trader Joe's.

One factoid to remember is that because so little phosphate is required to allow algae growth, one pound of man-made phosphate can stimulate the growth of 500 pounds of algae.

Quoting from an article by Michael Hawthorne in the Chicago Tribune, April 04, 2007:

'Detergent makers have spent most of the last three decades fighting to keep phosphates in their products, first in the courts and later through marketing. The industry eventually agreed to limit concentrations in most products … and stopped making phosphate laundry detergent in 1994.

'Yet most dishwasher soaps still contain phosphates, and enforcement of the law against them is spotty nationwide.

'There are a lot of people, even scientists, who mistakenly believe phosphates have been completely banned in detergents,' said Mark David, a University of Illinois environmental sciences professor. 'There hasn't been any pressure on manufacturers to change.'

Please let people in Lake Oswego know.

Craig Stephens is a resident of Lake Oswego.