Quick question. How many of you guys use aaD?

From the many courses on wetland soils I've taken I get the feeling that the majority of consultants don't use it. No consultant at a class has ever pulled out their own little amber bottles to test the soils. Its alway the instructors who are usually professional soil scientists from academia or NRCS.

Just this year I had a lab make a batch for me and I use it as much as possible for my data stations and in mitigation monitoring.

Just curious.

I don't currently use it mainly because of the short shelf life and storage requirements.

quote:

Originally posted by Tommy Dye:
I don't currently use it mainly because of the short shelf life and storage requirements.

Ditto, Tommy.

I also understand this test is better performed under laboratory conditions.

I was a little concerned about self life. When I got it made the least amount the lab would do was 1 litter; which will last awhile, but we have a fridge where I keep it in an amber bottle wrapped in foil. That should keep it from degrading for awhile. If I remember correctly heat and light are the main factors to be concerned about.

I'm sure there are more accurate lab tests for indicating reducing conditions, but to be able to check off reducing conditions in the field under hydric soil indicators that is the only test that actually indicates presence of Fe++. I know ORP meters test for redox potential, which I guess could be used to say there are reducing conditions present, but my aaD cost alot less than one of those. Plus that is just another piece of equipment to worry about.

It's not like it will make a huge difference on my call. I just see it as another tool and was curious if others were using it as well.

Thanks for the responses.

I feel that there should be better, readily visible field evidence of wetland conditions (flow patterns, rack lines, vegetation, easily determinable hydric soil conditions, etc.). It may be good supporting evidence but I would not hang my hat on it as "hard evidence".

I can't even keep my personal water supply cool in the field, so I'm not sure how to control the temp.

I have tried using it in the past without a whole lot of success in providing conclusive evidence of wetland conditions.

Of course, our new regional manual brings to bear such VAGUE things as "water present on aerial photograph", that maybe this will become an important tool (I hope not).

I see your point though, and had not thought about it - it may be helpful in mitigation areas where soils have not had a chance to change, and if your USACE rep likes it, then use it. In mitigation areas, I would prefer to put more weight on shallow hydrology data from electronic wells and onsite electronic rain gauges coupled with a rainfall analysis.

I used it all the time during one season in Alaska and liked it. You have to be careful the soil wasn't directly in contact with the metal shovel. I have started making my own, and just to make sure it is working, I go to an obvious site like a cattail wetland to test it.

I only started making it myself this year, and where I was doing the most work was South Dakota where almost all the soils where I was working were hydric anyway. It never gave a strong response in the dark soils I was working with.

I have no Idea about shelf life. I keep it in an amber bottle wrapped in foil, but not refrigerated. I will test it on cattails again next spring. Remember that it is somewhat toxic, so be careful.