Food Safety Network

IS OUR EXPENSIVE WATER TREATMENT GOING DOWN THE DRAIN?

02.may.05

Sources

• Vancouver Sun Nicola Jones

The charge for scrubbing the grit and bugs out of drinking water may, according to this story, be about to go up. And for many, the increase in water quality hardly seems worth the price. The story says that a month ago, the Coquitlam watershed turned on a new water treatment plant, a $45-million piece of machinery designed to pump ozone through water and kill off various bugs. A total of $300 million is being spent to upgrade equipment in three watersheds -- Coquitlam, Capilano and Seymour -- to include filtration systems, the ozone plant and a change in pH to make the water less acidic and therefore less corrosive to pipes. Dr. Bill Bowie, a professor of medicine at the University of British Columbia who has an interest in infectious diseases, was cited as saying he thinks the cost is probably too high for the benefits, adding, ``I’m one of the folks who has problems with the idea of spending massive amounts of money to make a good water supply marginally better,’’ estimating the Vancouver system was about 99.99 per cent safe -- even before the changes. Until now, the Lower Mainland watersheds have relied on chlorination to kill off the various bugs that might end up in reservoirs, including bacteria, viruses and protozoa. Assuming that the water isn’t too choked up with organic material, a chlorine concentration of about 0.2 to 1 milligram per litre (the concentration used now) will kill most critters if left to soak for a while. What it won’t do, however, is kill the protozoa such as Giardia and Cryptosporidium -- organisms commonly known by hikers for causing ``beaver fever’’ with its associated nausea, cramps and diarrhea. Before the change, there were about 10 Giardia cysts per 1,000 litres of our water supply. Doug Neden, administrator of water treatment and research for the GVRD, was quoted as saying, ``That’s considered relatively low.’’ There haven’t been any outbreaks of Giardia in the Lower Mainland, but there certainly have been elsewhere. And individual cases could be going unreported. Neden was further quoted as saying, ``There could be people getting sick. But if you’ve got low levels, you can’t tell where it’s coming from.’’ For those with compromised immune systems, such as the elderly, pregnant women or the sick, just one cyst could technically cause illness. But as Bowie points out, ``there is no system designed by man to make municipal water 100-per-cent safe to 100 per cent of people 100 per cent of the time.’’ Bowie argues that they could boil their water or get it from an alternative source.