We couldn’t do the work we do without help, and the work that Dillon Wilke has done for us is beyond exceptional.
Dillon came to us about 5 years ago after reading a story about the Spokane Riverkeeper in The Inlander. Jule Schultz, Technical Lead for Riverkeeper, put him to work almost immediately, teaching him how to take water quality samples in Hangman Creek in the Spokane River, and taking him out on sampling runs each month.
Dillon Wilke collects a fecal coliform sample in the Spokane River
Dillon was a quick study, as he had completed courses offered in a local hydrologic technician program. He was also eager to learn and had a flexible schedule. After working with Dillon for several years, we gave him a special project to work on – a pilot project sampling for harmful bacteria (E. coli) in Hangman Creek and the Spokane River. The purpose of this program was to determine if the Spokane River and Hangman Creek are safe to swim in using a low cost “Petrifilm” method of E. coli detection.
Fecal coliform is a bacteria that inhabits the gut of warm blooded animals and its presence indicates waste from either mammals or birds in the water. Swimming, drinking, or coming into contact with fecal coliform can make people sick. Samples with over 100 bacteria colonies per 100mL are considered unsafe for recreation.
Spokane Riverkeeper keeps a close eye on water temperatures and on fecal coliform levels. The purpose of monitoring river water for fecal coliform is to determine if the river is safe for swimming. If our sampling yields high numbers, we will report this information out to the public as well as notify the City of Spokane – so they can further investigate the cause of the pollution.
Past sampling by the Washington State Department of Ecology reveal Hangman Creek has fecal coliform levels due to livestock access and other reasons. If you know of places where livestock have access to the water in any part of the watershed, please report this to us and we can issue a complaint. Fecal coliform can also enter our watershed via pet waste, poorly maintained septic systems, malfunctioning sewer pipes, the stormwater collection system, and wildlife.
Bacteria colonies can be counted after 24 hours
For Dillon’s current volunteer project, he collects river water at five sites, both in Hangman Creek and the Spokane River. He collects the water in sterilized plastic bags, then brings the samples back to our office (sterile containers are necessary because we don’t want to take any chances that bacteria be introduced during the sampling process). In the office, a measured amount of the sample is placed on special growing media (Petrifilm), and placed in an incubator for 24 hours. If bacteria are present, they appear as colonies that can be counted (as in the photo at left). The number of colonies is multiplied by the amount of water applied to the filter to get a final bacteria count.
There are several types of bacteria, and various reasons and methods to test for them. Total coliforms are common in surface water, but are not pathogenic under normal conditions. Since E.coli is a species of coliform bacteria that is directly linked to fecal contamination from the wastes of warm-blooded animals, it is frequently the test used at swimming beaches.
Dillon measures out a prescribed amount of river water onto each counting plate
In Dillon’s last round of samples, the E. coli count for the Spokane River at the T.J. Meenach bridge was HOT, or really high. Over 100 colonies per 100 mls. How does the river water become contaminated with E.coli? Because it is present in the guts and/or fecal matter of warm blooded animals (including humans) it means that waste is getting into the water; from animals. Waste could also be entering the water from storm drains or cracked sewer pipes.
We were concerned about this very high amount of E. coli, so the next day we took another sample at that location and took it to the city’s certified lab to be re-tested. Several days later, the lab gave us results of 17 fecal colonies per 100 ml. Considerably lower. If this test was above 100 colonies/100mL, we would have notified the public.
The rationale for immediate re-sampling is based on lack of statistical sampling power with a single sample, and the possibility of collecting a false high count from a small localized source not representative of the overall bacterial water quality or human health concern. If the source of the bacteria is not small and isolated but rather a sewage spill or other large persistent source, the re-sampled count will also be high.
I spoke with Dillon, and asked him a few questions about why he volunteers and what he loves about the Spokane River. I was heartened by his answers:
“I volunteer because I want to give back to my community – and clean water is something we all really value,” he said. He also credits Spokane Riverkeeper for giving him a valuable education about Hangman Creek, saying “I had no idea how much negative impact Hangman Creek has on the water quality in the Spokane River.”
Every time Dillon walks into our office, we are heartened. Dillon’s work means a lot to us. If you see him out and about, please give him a thumb’s up!