Independent Volatile Gas Analysis Rules Out Dead Fish in Salton Sea Area--As usual the Official Story Stinks -- Couldn't resist-SQ
PRESS RELEASE: FOR IMMEDIATE RELEASE SEPTEMBER 13, 2012
Los Angeles odor problem, the Salton Sea, and dead fish
From the perspective of a company that specializes in odor analysis using analytical chemistry and instrumentation, we at Volatile Analysis Corp. (based in metropolitan Huntsville, AL) were fascinated by recent news of an obnoxious stinky odor reported in the Los Angeles area. Based on reported rotten egg odor descriptors listed by the LA times on Sept. 12, 2012, it is likely the odor problem reported in the LA area was due, in part, to hydrogen sulfide. However recent reports of a large scale fish kill probably had nothing to do with their odor problem. Dead fish don’t smell like rotten eggs. When fish die and decompose while floating on top of water (lakes, oceans, ponds), or washed ashore, they release very stinky odors that are chemicals called biogenic amines. Trimethylamine is one of the most notorious (others biogenic amines are named according to their odor and include putrescene and cadaverine). Biogenic amines tend to be reactive (like ammonia), and it is unlikely they would be perceived 100-150 miles away as was reported. Hydrogen sulfide would likely be produced from fish if they sank into the lake bottom and were decomposed anaerobically, although given the quantity of organic material present in the lake already (the lake covers an area approximately 376 square miles), the fish kill was probably insignificant.
Hydrogen sulfide is commonly produced in environments where there is little to no oxygen, high levels of organic material, and bacteria that thrive under these conditions (known as anaerobic fermentation). The Salton Sea, with its high salinity and low oxygen, certainly meets these criteria. Hydrogen sulfide has an odor threshold, meaning it can be detected by human olfaction, at 8 parts per billion (oehha.ca.gov/air/chronic_rels/pdf/7783064.pdf). This is very stinky stuff and the human nose has a very strong sensitivity for it. By comparison, the odor threshold for ethyl mercaptan, the highly odorous chemical most commonly used to give propane and natural gas the distinctive odor and aid in leak detection, is very nearly equivalent, at 1 part per billion (www.cdc.gov/niosh/docs/81-123/pdfs/0280.pdf).
Still it is extraordinary that hydrogen sulfide generated in a lake would be swept away by a thunderstorm and cause an odor problem 150 miles away.
Gas from anaerobic fermentation (conditions reportedly responsible for hydrogen sulfide) may also contain other highly odorous chemicals including butyric and valeric acids, skatole, and p-cresol. Interestingly other sources of hydrogen sulfide include natural gas and volcanic gases. If the hydrogen sulfide came from volcanic activity, there would also have been an abundance of other sulfur chemicals such as sulfur
￼dioxide, and strong acids including hydrochloric, and sulfuric acids. For example volcanic gas from Mt Kilauea contained 0.04% hydrogen sulfide (40,000 parts per million!), 11.8% sulfur dioxide, and 0.08% hydrochloric acid (http://volcanoes.usgs.gov/hazards/gas/index.php). These chemicals would contribute to the overall stench sensation (as anyone who visited the Big Island would undoubtedly verify!). Increasing the types of chemicals sampled in LA air beyond hydrogen sulfide would have provided clues to more completely solve this mystery.
Note: The conditions for volcanic activity are very different when comparing hotspot activity in the Hawaiian Islands vs. along the San Andreas Fault (the fault runs below the Salton Sea). Gases generated by plate tectonic action are not as readily available for analysis as they are from Mt. Kilauea.
Specializing in identification and measurement of odorous chemicals and providing expert witness services, Volatile Analysis Corporation is an industry leader in odor analysis. The company’s website is http://www.volatileanalysis.com.
Sep 14, 2012