Public Lab Research note


370nm UV detection of Corexit-dispersed oil on Gulf Coast Beaches

by eustatic | April 20, 2012 23:51 | 169 views | 3 comments | #1724 | 169 views | 3 comments | #1724 20 Apr 23:51

Read more: i.publiclab.org/n/1724


James "Rip" Kirby, USF, of The Emerald Coast Chapter of Surfrider, a beach advocacy organization, has published a report wherein UV light was used to screen for BP oil, which was largely dispersed with Corexit 9500A/9527.

The UV light-at-night shows dramatic results, but is not sufficient; the report details some false negatives were found for deeper sands when samples were analysed in the lab Mass Spec and chemically (photo pg 14).

http://surfrider.org/images/uploads/publications/Corexit_Connections.pdf

from the abstract.

"The use of ultraviolet light equipment in the field showed distinct fluorescent responses to illumination by a 370nm UV light source. UV light equipment was found to be very efficient in identifying tar product on the beach for evaluating the visual level of contamination on the beach. Fluorescent responses from tar product found in the field and laboratory created tar product were measured by fluorometry equipment."

from the conclusion

"The presence of Corexit® brand dispersant treated crude oil as provenance for weathered tar product can be determined by examining its fluorescent response to 370nm wavelength UV light. The fluorescent response, or signature, of the tar product shifts toward red as the amount of dispersant increases. Thus, higher ratios of dispersant to crude oil used during clean up operations can be subjectively determined.

Published research confirms that microbial degradation of tar product is inhibited by the presence of Corexit® dispersant still bound to its molecular structure. Finding tar product using UV light is a proven solution to improving physical removal methods. "

~20 pages of text and diagrams, 220 pages total. most of it is report data. contact info for Kirby and Erica Canales of Surfrider is in the chain of custody paperwork.

Files Size Uploaded
Corexit_Connections.pdf 2.39 MB 2012-04-20 23:50:20 +0000

3 Comments

I've been on a few calls with Erika and Mike of Surfrider Emerald Coast / Walton Beach, as part of the Gulf Future organizing effort.

Gulf Restoration Network has a stash of Barataria bay oiled sediment from marshes and sands of Louisiana. Jonathan just got back from vacation in Florida, i'm sure he got some more tar there.

*leaves to look at UV lights at auto parts stores

Reply to this comment...


Scott - i bought a nice UV lamp that's bright, durable and cheap on Amazon:

http://www.amazon.com/LEDwholesalers-Ultraviolet-LED-flashlight-7202UV395/dp/B001Q70A0G/ref=sr_1_1?ie=UTF8&qid=1334967480&sr=8-1

it says 395 nm - but we can test that on the spectrometer to double check - check out this test with the PLOTS spectrometer:

Is this a question? Click here to post it to the Questions page.

Reply to this comment...


sorry it's not displaying both spectra - but here's the raw UV LEDs:

the other spectrum (the first one) is actually of UV light reflecting off of makeup -- foundation.

Reply to this comment...


Login to comment.

Public Lab is open for anyone and will always be free. By signing up you'll join a diverse group of community researchers and tap into a lot of grassroots expertise.

Sign up