I’m working as an environmental consultant these days and one of the things that I’m constantly looking into is whether or not my sites that are impacted with various soil and groundwater contaminants are under regulatory control of the state and/or federal government.
“Wait, you mean you can have soil and groundwater contamination that isn’t regulated?”
Well, sort of.
When you spill oil all over the ground at your property and don’t tell anyone, and you live there for a long time, you don’t think of it. Then you sell the property down the road and whomever bought it decides to knock your old house down and build a new McMansion. In the process, they come across your oil in the soil, but…it’s not just oil. Water has infiltrated the soil and carried some or all of it deeper into the earth. There are microbes that live in the soil who LOVE to eat petroleum hydrocarbons. They’re seriously so incredibly happy that you poured the oil on the ground that they’ll gobble it up…very slowly. That takes some time.
So, decades later when someone’s redeveloping your old property, they come across some sludgey stuff. Not sure what it is, but knowing that it’s not quite pristine soil, the earthwork contractor decides to call a professional.
Someone like me comes out, looks at the hole in the ground, and pokes around with a shovel, and decides to grab a soil sample. There’s no groundwater in the hole, and the area of sludge and soil hasn’t gone too deep. There’s no evidence for anything on the site that would have caused the sludge. So yeah, I grab a soil sample and drive to the analytical laboratory.
Well, the nice thing is that the Washington State Department of Ecology has been there before. A lot. And well, most of the time, when you have stuff spilled on the surface and it’s sludgy, there’s a pretty good chance it’s petroleum-based. Sometimes there’s a dry-cleaners involved (but those solvents smell very distinct and they tend to move into soil and groundwater…fast), sometimes there are other, more exotic chemicals involved (metals, radiation, fancy organic compounds), but it’s usually an old gas station or some old guy who didn’t get the memo about not pouring used oil down the storm drain.
They have toxicologists who have studied the effects of chemicals on humans, animals, worms, voles, plants, you name it! (Actually, in writing this post, I finally discovered what a vole is, and they sure are cute!)
Yup, the Department of Ecology has studied all of the chemicals are that are there to study. Actually, it’s a really daunting task, because there are so many man-made chemicals that haven’t gone through any kind of testing, and so many more that we’re discovering aren’t good for us, or the voles, and…it’s a constant process. Thankfully, Washington State is on it!
They and I are probably hoping that site you’re working on is simple and that’s it’s just common petroleum hydrocarbons, a.k.a. anything that consists of a whole bunch of hydrogen and carbon molecules strung together. The nice thing about basic hydrocarbons is that they float on water and are really easy to discover, unlike dry-cleaning solvents, which are heavier than water and sink, and as a result, are notoriously difficult to deal with.
If you’re dealing with basic, simple, petroleum hydrocarbons, then Ecology has a publication for you! Guidance for Remediation of Petroleum Sites (PDF) is pretty heavy on the technical side, but it tells you how to identify and clean up these sites. Here’s the breakdown:
Step 1: You discover the stuff. You have to contact your regulator within a certain amount of time and tell them what you plan to do with the spill. They’ll give you guidance, but…you might want to hire someone like me.
Step 2: Poke holes in the ground to determine what the spatial limits of your contamination is. This may involve poking holes all of the way down to groundwater. The groundwater contamination, if it exists, will likely cover a much larger area than the soil.
Step 3: Figure out how extensive the soil contamination is and whether or not it will affect “sentitive” creatures: kids, pregnant women, fish, voles.
Step 4: Determine the site land use. Obviously something in a heavily industrial area will be a lot different than a rural school.
Step 5: Do some other fancy-schmancy stuff, based on the land use, but basically, determine what your cleanup levels will be. Most of the time, they’ll be based on a general, unrestricted land us (a.k.a. that anyone can walk onto), but you might have an industrial site that won’t see kids or animals. This is the step where you can have a much less conservative cleanup level (or more conservative), based on specifics.
So you have your cleanup levels. You test your soil. You determine it’s some kind of petroleum and based on whatever land use type cleanup levels you have, your concentration of oil in the soil (and all of the other potential contaminants, like lead, PCBs, etc.) is lower the regulatory concern. Therefore, you document document document, but there’s nothing else to do! If it’s above cleanup limits, then you have to remediate the site (dig it up and truck it to a landfill, use bacteria that like to eat the oil, burn it up in an incinerator, etc.). But of course, before you do that, you have to contact the authorities and tell them what you’re doing…and they’ll probably want to give you a little help along the way. They’ll help you approve a cleanup plan which should make it a bit easier for them to say, at the end, when everything’s cleaned up, “No Further Action!” (PDF).
That’s all I feel like writing tonight. I have a lot of other stuff to write about on this basic topic and by explaining it, it helps me do my day job. Expect more soon!