E. Coli, Mushrooms, & You

The Battle for North Creek

E. Coli in North CreekWe have certainly been over this before.

Fecal Coliform levels in North Creek are way, way above federal and safe limits., it was placed on 303(d) list in 1996. State water quality standards require mean bacteria counts of 50cfu/100mL not exceeding 100cfu/100ml. Non point sources of pollution include: contaminated soil from the former pasture, stormwater runoff during rain events, and the large crow population.

Battling the Feces

-The North Creek Wetlands was created to act as a filter for stormwater runoff from downtown Bothell and its urban watershed and drains approximately 30 square miles and discharges to the Sammamish River, which is tributary to Lake Washington.

-Data shows E.Coli levels are way above public health standards

-Has multiple waterways contaminated with Fecal Coliform, but a big source is from SW2

-Local government programs include: water quality monitoring, education and outreach to raise awareness

SW 3 after a heavy rain event. (photo credit David Jackson, 2016)

Enter the Shroom- Mycelium is the root structure of fungi. Mycoremediation utilizes fungi to reduce contaminants in water.

- The mycelium secrete digestive enzymes that have been shown to break down a wide variety of toxic molecules into simpler components.

-“Waddles” are being constructed from different materials that biodegrade and inoculated with mycelium, then wrapped in burlap.

-The waddles are then planned to be placed across contaminated streams and is slowly filtered as it enters one end. So in theory, “clean” water is discharged through the other end.

-By using a box filter filled with mycelium, samples of controlled and contaminated water were filtered through the mycelium and the filtered water would hopefully show a reduction in E.Coli

The Mighty Box FilterThe top section was perforated, to allow our raw samples to drain through. It has to be sterilized after each use.

The second section is filled with mycelium (Oyster Pearl) and a substrate. This is also perforated to allow water to pass.

The third is empty to catch the water that has passed through the filtering mycelium. It has tic marks showing water levels so we can measure residency time.

Raw Water

Mycelium

Filtered Water

Round One!We used water gathered from North Creek near SW4. We took about 8 gallons out to ensure we would have enough.

We sampled from the raw stream water, weighed the mycelium, and then poured 4,000 mL (just over 1 gallon) into the box filter.

It took a little over a minute for most of the water to drain. (1:18 second for ~3750mL).

We took samples from the filtered water, and from the water that dripped out more slowly, and set all of them to culture.

If at First You Fail...

As you can see, we the results were not what we hypothesized.

E. Coli increased in both samples after it had been run through the mycelium. In the drip, the other coliform counts were higher than ever.

What Went Wrong

Immediately we came up with several ideas:

- Maybe the mycelium or substrate was loaded, we should have run distilled water through first and tested it.

- Maybe the residency time was too low.

- Maybe the sample we used wasn’t sufficiently contaminated with E. Coli.

Round Two!We decided to address two problems at once. - We would run another test, but start with distilled water to ensure that we

had no contamination in the mycelium itself. If the distilled water (di water in our notes) came back contaminated, then we would know why our numbers were off.

- Secondly, we decided to take a smaller sample, only about 3 gallons, from directly in SW4 to ensure we had the same, high contamination rate we were missing with the previous sample. It would still leave us with enough to run the box filter experiment and get plenty of samples for culturing.

- We took our raw samples, weighed the mycelium, put the distilled water through (2000mL this time), and took the filtered samples.

- We then weighed the mycelium again, put our pond water through (2000mL), weighed the mycelium one last time, and took samples from the filtered water.

The Un-Amazing DiscoveryThe distilled water showed us nothing. Neither the mycelium nor substrate were not loaded with fecal coliform.

However, it also did not show us a any remediation of the fecal coliform counts.

The issues we tried to control for weren’t the problem after all.

Pearl vs. King: The Hypothesizing

The graph to the right shows the percentage of E. coli that was remediated by a “runthrough” similar to ours. This runthrough, however, used King Stropharia.

Note that the reduction was significant, where our runthrough with Pearl Oyster was not.

This leads us to believe that Oyster Pearl requires greater residency time than King Stropharia to clean Fecal Coliform.

Citations

1. Turner, R (2016). Personal communication. BES 318 course lecture.

2. Revised Total Coliform Rule And Total Coliform Rule. Federal Register (FR) on February 13, 2013 (78 FR 10269). Available from: https://www.epa.gov/dwreginfo/revised-total-coliform-rule-and-total-coliform-rule#rule-summary

3. Malloney K. 2016. Mycoremediation project outline, spring. UWB.

4. Malloney K. 2016. E. Coli Analysis. UWB.

5. Ralph Svrjcek. 2003. North Creek Fecal Coliform Bacteria Total Maximum Daily Load: Washginton State Department of Ecology; 03-10-047.

6. Department of Ecology State of Washington: [Internet]. [cited 2016 May 30]. Available from:https://fortress.wa.gov/ecy/publications/documents/0210019.pdf