By Jayson Jacoby
Each of the past 17 samples of Baker City water tested has been free of cryptosporidium.
These results, which date to mid-August, don't mean the city can relax its testing regimen in the wake of the crypto outbreak that sickened hundreds of residents in July and August.
The city will continue to collect two water samples every week, probably until an ultraviolet light treatment plant is operating, City Manager Mike Kee said this morning.
City officials hope that plant will be finished by late summer of 2014.
Still and all, the continuing series of crypto-free water samples brings a certain measure of relief to City Hall, Kee said.
"Of course we're pleased about that," he said.
Kee pointed out that the recent water tests don't paint a complete picture, though, because the city is not tapping all of the dozen streams and springs in its watershed in the Elkhorn Mountains.
With autumn chill replacing summer heat, water use has dropped considerably, so the city doesn't need to use all its sources, Kee said.
Although neither state nor federal health officials who visited Baker City this summer have pinpointed the source of the crypto outbreak, the most compelling piece of evidence is a water sample taken from Elk Creek on Aug. 4.
That sample contained 913 crypto oocysts (the shell that surrounds the parasite and makes it resistant to the chlorine the city adds to its water as a disinfectant).
No other water sample, from any source in the watershed, has contained more than three oocysts.
The city has not used water from Elk Creek since Aug. 7, the day it received the lab report for the sample collected Aug. 4.
The city has, however, had two samples of Elk Creek water tested in the past several weeks, and neither contained crypto.
Cattle, which are known to carry the species of crypto that was confirmed in seven local residents who became ill this summer, were seen during August near the site where the city diverts Elk Creek water into its pipeline.
As a safeguard the city hired a contractor to build a fence around a 40-acre parcel in that area.
In addition, on Thursday inmates from the Powder River Correctional Facility removed animal feces from the same area, Kee said.
About 80 percent of the feces was from cattle, and the rest from elk, he said.
Although cattle feces samples tested in August did not contain crypto, Kee said he believes having the inmates remove droppings from near Elk Creek is a worthwhile precaution.
"We're doing anything we can think of to minimize the risk of having a detection (of crypto in the water)," he said.
State officials have said that if two consecutive water samples contain any number of crypto oocysts, then the city would have to reinstate the boil water order that was in effect from July 31 through Aug. 20.
However, Kee said that if even a single water sample tests positive for crypto, he intends to stop using water from the watershed and switch to using only water from the city's well.
Based on the low demand during winter, the well should provide plenty of water until March or April, Kee said.
The city also is continuing to try to determine whether an old well at the city-owned Quail Ridge Golf Course could be used, and officials are investigating a couple of other wells on private property in Baker Valley.
"We need to get some wells on line," Kee said.
One encouraging thing, he said, is that water samples were crypto-free even after heavy rain fell during September.
Health officials say it's possible that crypto contaminated water after downpours in late June caused runoff to carry crypto-containing animal feces into a stream the city uses.
Kee noted, though, that small numbers of crypto oocysts can enter the water even during the winter, when snow and frozen ground limits runoff.
One of the three (out of 24 total) water samples tested during 2010 and 2011 that contained crypto was collected in December. Two of those three samples contained one oocyst, and the other sample had two oocysts.
The Oregon Health Division didn't require the city to take any action as a result of those three positive tests because the number of oocysts was low and because no cases of crypto infection were reported during that period.