False Positives in Spill Cleanups: The BIC Picture

Spill cleanups can be tedious, resource-consuming, and COSTLY. Some of the costs I've seen is where companies are cleaning up spills onto soils where contaminant doesn't really exist! Why is this?

I've seen it before in hydrocarbon spills where soil samples SHOULD be clean. Yet the lab results come back with "Hits" - a positive number (usually in the F3 range). It turns out that they were FALSE POSITIVES. A false positive is where a value is observed yet it is "not really there". For example, an interference gives a value for a chemical, or something similar gives a value. Background values were not subtracted. There are many reasons.

A quick Lesson on Hydrocarbons: in general, they range from lightweight products (Benzene, toluene, Methane) - those with low Carbon Numbers. These have low boiling points and are often gases at room temperature, and standard atmospheric pressure (think butane in a butane lighter). As we get more Carbon's in the product, the boiling point goes UP. This is exactly how they are analyzed in the laboratory; heat is added, and they turn to gas, and they elute through a column before being detected; so lighter products come out first, heaviest (think oils, greases, bitumen) come out last.

In spill cleanups, there's some background material that may give a false positive. These are organic products that exist in nature. Fats, Lipids, pine tree oils, turpentines. In an attempt to generalize this to one clients, I once said "Essentially, it's bug guts being read by the machine". Feel free to use the analogy!

The AEP has recognized this! And they now have a guideline. The Biogenic Interference Calculation Scale [BIC Scale - see intended-Pun in article headline :) ]and regulatory requirements for use in Alberta has been published. Find it HERE. (Figure Credit; exerpt from AEP Document). Use it to apply PHC F2, & subfraction F3b's to the Alberta Tier 1 Soil Guidelines if you are working on a Spill.

Chinook Environmental Services also has professionals, teams and consultants ready to help you out if you have a spill. Please feel free to call us at 1-866-866-4593 or visit our website at https://www.chinook.com