Life Fights Back: Detection of Oxygenation of Petroleum Contamination by Microbes.

[NNadir]

As my life winds down, I worry all the time about the destruction to the planet my generation has wrought and whether or not the planet will ever be healed.

There isn't much good news on stopping the destruction; indeed, the preferred "solution" for the energy and environmental disaster is to destroy more wilderness with huge industrial facilities we misname "renewable energy." (It's dependent on vast land use changes as well as vast mining - there's nothing "renewable" about it.)

The petroleum industry was driven by the rise of the automobile, the automobile being proposed early in its history as a means to address an environmental problem of the 19th and early 20th century: The accumulation of horse manure in cites.

That worked out well, didn't it?

I wonder what the legacy pollution of the automobile, which I expect will not go away for tens of millions of years, if ever.

I'm used to pessimism I guess, but here, for what it's worth is a little bit of good news, involving the damage done by the operations of a petroleum refinery that seems to be somewhere in Colorado, as reported in the following paper:

Discovery of Oxygenated Hydrocarbon Biodegradation Products at a Late-Stage Petroleum Release Site Olivia K. Bojan, Maria Irianni-Renno, Andrea J. Hanson, Huan Chen, Robert B. Young, Susan K. De Long, Thomas Borch, Thomas C. Sale, Amy M. McKenna, and Jens Blotevogel, Energy & Fuels 2021 35 (20), 16713-16723.

Some text from the introduction of the paper:

Subsurface releases of petroleum liquids are among the most common causes of soil and groundwater contamination in the world. Spills can range in size from 10s to 100 000s of cubic meters at various sites from retail to refining facilities. Typically, a substantial share of subsurface light nonaqueous phase liquids (LNAPLs) are biodegraded anaerobically to CO2 and CH4 through natural source zone depletion (NSZD) processes. (1−5) Biogenic gases migrate upward through off-gassing and ebullition to the vadose zone where the methane is mineralized by methanotrophs using downward-diffusing atmospheric oxygen. (5−7) The fate of subsurface petroleum liquids follows the short-term carbon cycle wherein C–H bonds are iteratively replaced with C–O bonds and ultimately oxidized to CO2, which cycles back into organic compounds via photosynthesis.

Subsurface petroleum releases evolve with time. (8) Early stage releases are largely about expanding pools of unaltered LNAPLs in transmissive zones of the aquifer. At early stage sites, active recovery efforts are commonly employed to deplete LNAPL to the extent practicable. (9) With time, NSZD and active recovery efforts transform early stage LNAPL sites into middle-stage sites, where continuous LNAPL is largely depleted, while dissolved-phase total petroleum hydrocarbons (TPH) as well as benzene, toluene, ethylbenzene, and xylenes (BTEX) persist in groundwater. Soluble species move into low-permeability (low-k) zones within the aquifer via slow advection and diffusion. Given the limited efficacy of active remedies at middle-stage sites, NSZD often emerges as the primary factor driving the maturation of LNAPL sites with reported rates of cleanup due to NSZD ranging from 1000s to 10 000s of liters per hectare per year. (10)...

Benzene. Recently at DU there was a hullaballoo about the detection of benzene in cosmetic products. The attention paid is something of a cruel joke to anyone who is familiar with chemistry of petroleum. If someone is really concerned about benzene, they should be working on banning petroleum, and not with wind turbines and solar cells, but with something that works on scale.

Won't happen.

The oxidation of petroleum to CO2 is not without some intermediate risks according to the authors, further on:

...Of emerging scientific, engineering, and regulatory concerns are oxygenated hydrocarbon transformation products, sometimes referred to as “polar hydrocarbons”, “oxyhydrocarbons”, or “petroleum biodegradation metabolites”. Oxygen-containing metabolites such as organic acids, esters, alcohols, phenols, aldehydes, and ketones are generated through biologically mediated “weathering” processes. (12) Partially oxidized petroleum metabolites can comprise up to 100% of the extractable organic carbon in the downgradient groundwater plume (2,13,14) with a principal concern being increased water solubility and mobility of metabolites in aqueous environments. (15−17)...

The authors found a place to study this, an abandoned petroleum refinery which is not named, probably to prevent the owners from facing lawsuits and bad publicity, and use some novel techniques, cryogenic coring, via the injection of liquid nitrogen, followed by the use of the ultra-high resolution mass spectrometry available at the National High Magnetic Field facilities in the State that recently seceded from human decency and democracy with Baby Putin Desantis, Floridistan.

...Herein, we uniquely explore a late-stage petroleum hydrocarbon-contaminated site in both transmissive and low-k zones at the upgradient edge of a 40-year-old depleted petroleum LNAPL body at a former refinery. Our work was motivated by the vision that an enhanced understanding of the nature of late-stage sites will support better-informed decisions regarding best management practices for middle- and late-stage petroleum LNAPL sites...

By the way, the effects on ground water from an abandoned petroleum refinery will pale when compared to the effects on ground water obtained from fracking while we all wait, breathlessly - our breath becoming more dangerous by the hour - for the grand electric car/wind/solar nirvana that has not come, is not here, and will not come.

Anyway, the petroleum is being metabolized, which over tens of thousands of years may prove to be a good thing, immediate effects on ground water notwithstanding.

Organisms in the petroleum contaminated soil:



The caption:

Figure 2. Active microbial community composition and relative abundances in the oxic transmissive zone and in the anoxic low-k zone. Assignments were made at the genus level; in cases where genera were unclassified, higher level taxonomic identifications are reported, but grouped taxa shared >95% sequence similarity. Not detected indicates that no amlicon could be generated for sequencing.

Counts of the hetero atoms in molecules associated with the metabolism of petroleum:

Figure 3. Heteroatom class distribution derived from (− ESI FT-ICR MS for toluene-soluble extracts in the anoxic low-k (blue) and oxic transmissive (red) zones.

It's problematic that in the absence of oxygen, methanogenic organisms release the potent greenhouse gas methane, but letting water flow into the petroleum avoids this problem.

An excerpt of the conclusion:

Our molecular-level investigations of the transmissive and low-k zones in a heterogeneous aquifer offer a unique and astounding first glimpse at a late-stage petroleum hydrocarbon release site. At this particular study site, petroleum hydrocarbons in the anoxic low-k zone must be primarily biodegraded under methanogenic conditions. However, a small diffusive influx of molecular oxygen from river water recharge in the oxic transmissive zone likely leads to limited aerobic metabolism and the accumulation of highly oxygenated metabolites. In contrast, more abundant O2 in the transmissive zone enables the rapid aerobic mineralization of petroleum hydrocarbons without the accumulation of highly oxygenated species. Biodegradation processes are active for a broad range of petroleum hydrocarbons, from aliphatic to aromatic compounds as well as from low- to high-molecular weight components...

I'm not quite sure how well humanity will survive, but it's comforting to note that probably life itself will.

I trust you're having as pleasant a Sunday as one can have in a time of tragedy.

[harumph]

1. Planet of the grease monkeys