GUEST OPINION BY
Richard Llewellyn, PhD Biochemistry
Boise City plans to dump water they claim is “treated” into the Farmers Union Canal and the practice could be costly for water users and property owners alike.
Turns out the water is laced with trace chemicals from dozens of sources and it just may lead to a massive government mandated clean up requirement. They like to use the term “water renewal,” but true renewal is costly and not in the plan.
That’s why an increasing number of water users are saying that the City of Boise’s plan to dispose of ‘forever chemicals’ into our region’s iconic irrigation canals needs a lot more serious review … before we give “America’s Most Livable City” a “forever headache”.
PFAS — per-and-polyfluoroalkyl substances — are a fancy way of saying the trace chemicals that end up in our wastewater that aren’t captured by our water treatment plants. Along with thousands of other chemicals from shampoos to birth control pills, antidepressants, and antibiotics, as well as the contaminants sent to the plants by industrial and medical facilities, these aren’t removed by wastewater treatment. They aren’t the pee, but they’re in the pee … and in many of the other stuff we send down the drain.
They don’t belong in our irrigation water … or in the crops and gardens that we grow with the vital water on which they depend. Nor do they belong in our groundwater, where our irrigation water ends up.
In a nutshell, the problem is that the chemical reality of wastewater has diverged so far from the standard treatment technology that it is plausible that just by irrigating with recycled water we could end up with property that exceeds future standards for hazardous designation. Hazardous–as in, you may need to excavate and truck your soil to a hazardous waste site before anyone will buy your land.
If that statement sounds incredibly far fetched then read on. Sewage treatment plants were designed to deal with sewage. A city like Boise does a good job with that and strives to do better. That alone isn’t easy, and requires significant long term investment especially as a city grows or infrastructure budgets fall. Search online and every week you will see a sewage spill somewhere across the country.
Today, however, municipal wastewater is not just sewage but a complex mixture of tens of thousands of chemicals. Many of these are ‘endocrine disruptors’–chemicals that mimic hormones and interfere with the body’s internal communication at trace levels. Collectively these substances are known as Contaminants of Emerging Concern (CECs). PFAS is one that has emerged like an 800-lb gorilla busting into a board room.
PFAS make up a family of thousands of related chemicals — fluorinated carbon chains that are used widely in industry to make oil- and water-resistant coatings. They are best known for their use in Teflon, but are also in fire-fighting foams, industrial coatings, stain resistant carpeting, and many consumer products. Eventually they end up concentrated in municipal wastewater.
Some top researchers conclude that essentially no amount of PFAS is safe in drinking water, and yet it is not regulated at the federal level, though many individual states have recently passed standards in the parts per trillion levels, and for soils in the parts per million to billion. Contamination from wastewater treatment plants are already triggering lawsuits — Orange County, California, for example, has started closing wells while considering a billion dollar lawsuit against chemical manufactures due to PFAS contamination they blame on treated municipal wastewater discharges upstream.
Because these ‘forever’ chemicals may take almost forever to degrade, a back of the envelope calculation gives us an idea of how much PFAS will be carried to your land, and how much can be expected to remain. For that, we have to deal with a few numbers, and a whole bunch of decimal points:
For every part per trillion (ppt) of PFAS in the effluent, you could get 2 milligrams of PFAS in the water used to irrigate one acre for one season, after accounting for dilution in the canal.
Once on your property, the chemicals will either leave in runoff, go down into the groundwater, up into plants, or remain in your soil. Each of the thousands of types of PFAS will move differently. Certain crops take them up more efficiently — for example corn has been found to store more than 12% of one kind of PFAS.
We’ll also assume you are a good steward and keep the water on your land in a small (24×24 foot) waterfowl marsh rather than letting it run off. For a rough calculation, let’s assume half of the added PFAS accumulates in the top yard of soil in that marsh.
This adds about PFAS 0.017 micrograms per kg soil per year for each 1 ppt PFAS in the effluent. And as it is likely that the effluent from Boise will have at least five ppt PFAS, multiply that by five. After the 25 year contract with Farmers Union Ditch Co, you could have about two micrograms in each kg of soil.
What does this mean for you? A microgram may be a tiny amount, but individual state soil standards enacted within the last few years have a vast range of thresholds — with one milligram per kg fairly common, but for areas that are easily accessible and drain to important groundwater, some levels are far lower — as low as half a microgram per kg. Crucially, there are currently no federal standards at all, but many experts assume that PFAS will soon be listed as a hazardous substance, either as individual chemicals or in groups.
If coming federal standards reflect the more stringent regulations, the seemingly preposterous is true–you could be faced with having hazardous soils within a decade simply by irrigating. And as good science supports the most strict standards, especially to protect the health of pregnant women and children–the real issue will be whether it is feasible to enforce them.
The WateReuse Association, a member of which Boise has contracted to advise on using recycled water, is energetically lobbying all levels of government that the wastewater industry be exempt from any PFAS liability. The question remains as to whether those of us who continue using our shares of water as we have for more than a century will also be exempt — and whether we can convince any future buyer that they will be too.
This is just a back of the envelope calculation, but it shows that a serious investigation is needed. One might assume that an agency will do it for us — but, as an Idahoan, it should come as no shock that you need to look out for yourself and for your neighbors: Idaho DEQ recently granted the City of Nampa a similar water recycling permit for the Phyllis Canal, and PFAS was not mentioned once.
Be sure to comment to Boise City Council this Sept 15 to voice your concerns on any future plan for water reuse.
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