I just found out that the soil I've been using for making my garden beds has been contaminated by our septic system "leaking," and I'd like to know how dangerous it is to grow in, as well as how long it will stay contaminated.
A bit of background: The previous owner of my property decided to tinker with the septic system. He removed about 4 feet of pipe that ran between our septic tank and our sand filter. He replaced the pipe with sand and covered it all with dirt. I guess he figured the septic waste would follow the sand's path of least resistance uphill and flow happily and magically into the sand filter. The guy's nuts. A few weeks ago, we were outside when the septic system pumped up, and noticed the smell and the liquid of our sewage leaking out of the soil. We dug, found the "leak," and fixed it. But, where the sewage was leaking out is also were we have extra soil that we've been using to make hugelmounds for our blueberries. I don't know how long the sewage has been leaking there, or how much has accumulated in the soil. How dangerous is it? When will it be safe to garden with?
To add to the mess, part of our property is protected wetlands, which this sewage has also been flowing happily into. For being a lawyer, the previous owner really messed things up!
This is a perfect example of soil fungi taking care of the problem while you worry about what to "do". You really don't need to "do" anything if the soil fungi are healthy and working.
Does this area smell bad? I don't mean just odors wafting up from the septic. I mean dig down two inches, get a handful of dirt and smell it. If it smells like sulfurous swampy marsh dirt, then you still have a problem. If it smells earthy and has an odor reminiscent of mushrooms, then all is well.
Do mushrooms pop up in this area after a heavy rain? If so, that is another indication all is well.
I wouldn't be worried about the hugelbed with the blueberries, the wood you buried should be teeming with fungi that are eating up septic tank escapee microbes. If you feel you need to do something, spread around a couple inches of moldy wood chips. All that extra fungi will quickly clean up any problem that remains.
Thank you! This is very reassuring. The soil is already forest soil (under a hemlock tree we recently cut down, since it was two feet from our house and growing out of a stump and had metal stakes up it from the previous owner who installed a satellite on top of it). Though I haven't seen any mushrooms popping up there (probably because we've been digging, as there are some nearby), the soil does not stink. My husband added some really rotting pieces of wood to the hugel, too. So, I think we're safe. Thank you again!