The results from our septic soil testing have been received and are provided in the table and Excel file here:
We should not jump to conclusions or assumptions based on only one set of soil tests. Please don’t point fingers at neighbours or assume that you system is fine yet. We should have multiple tests over several time intervals to be reliable and able to come to more accurate conclusions.
However, these results do point to issues and the need for additional testing. While I wouldn’t put too much significance on any one data point there are several trends that are apparent:
– year-round cottages tend to have higher phosphorous readings in their lawn soils which is logical because they are likely getting more use and having to process more nutrients,
– places with dogs tend to have higher nutrient levels in their lawns,
– newer active septic tanks have just as high or even higher phosphorous levels than other septic systems which simply confirms the fact that septic systems do almost nothing to break down or remove phosphorus – only specific phosphorous filters that have just come on the market in the past year can do this,
– some of the highest levels are at cottages that have been used the longest which is logical since phosphorus and other nutrients build up in the soil over time until the soil can absorb no more then any excess is washed away into the surrounding water ways,
– some of the data raises more questions than it answers which means we simply need more data and testing – unfortunately the Olsen P tests used for soil phosphorous testing are very time consuming and expensive.
Once again, we need to do everything that we can to limit phosphorous and nutrients (limit soaps, shampoos, fertilizers), remove existing nutrients from the ecosystem (septic tank pumping, removal of compost and other nutrient rich debris), and filter any future sources of nutrients to remove/breakdown phosphorous (septic filters, bioswales, wetlands).