An Elm Dirt company·Kansas City, MissouriCDFA Certified Organic
Elm Dirt, Together We GrowRemediation

Contaminant group

Chlorinated Solvents & VOCs

Degreasers, dry-cleaning fluid, vinyl chloride and the chlorinated ethanes. Biology has a full-scale field record here, and several organisms in our products have published research on these compounds.

What biology does
Breaks down
Microbes in our products
P. putida, D. dichloroeliminans, P. stutzeri and 2 more
Shows up at
Train Derailments, Brownfields
Diagram: Chlorinated Solvents & VOCs, microbial action, outcomeSmall chlorinated molecules that move readily through soil gas and groundwater. Aerobic bacteria oxidize some compounds, while others need anaerobic specialists to strip chlorine. Breakdown: in the research. Bacteria remove chlorine step by step, and complete routes end in chloride, carbon dioxide and water. Binding: treated in place. These compounds move easily, so biology treats them where they are instead of binding them.01 CONTAMINANT02 MICROBIAL ACTION03 OUTCOMEClClCl Chlorinated Solvents & VOCsSmall chlorinated molecules thatmove readily through soil gas andgroundwater.Microbial actionAerobic bacteria oxidize somecompounds, while others needanaerobic specialists to stripchlorine.CO2H2OIN THE RESEARCHBreakdownBacteria remove chlorinestep by step, andcomplete routes end inchloride, carbon dioxideand water.TREATED IN PLACEBindingThese compounds moveeasily, so biology treatsthem where they areinstead of binding them.Diagram: Chlorinated Solvents & VOCs, microbial action, outcomeSmall chlorinated molecules that move readily through soil gas and groundwater. Aerobic bacteria oxidize some compounds, while others need anaerobic specialists to strip chlorine. Breakdown: in the research. Bacteria remove chlorine step by step, and complete routes end in chloride, carbon dioxide and water. Binding: treated in place. These compounds move easily, so biology treats them where they are instead of binding them.01 CONTAMINANTClClClChlorinated Solvents & VOCsSmall chlorinated molecules that movereadily through soil gas andgroundwater.02 MICROBIAL ACTION Microbial actionAerobic bacteria oxidize somecompounds, while others need anaerobicspecialists to strip chlorine.03 OUTCOMECO2H2OIN THE RESEARCHBreakdownBacteria remove chlorine stepby step, and complete routesend in chloride, carbondioxide and water.TREATED IN PLACEBindingThese compounds move easily,so biology treats them wherethey are instead of bindingthem.
Fig. 1How biology acts on chlorinated solvents & VOCs, as described in the peer-reviewed literature. Rates depend on soil, moisture, oxygen and temperature, and are confirmed by lab testing over months.
On this page (7 sections)
  1. What Elm Dirt does about solvents and VOCs
  2. What it is
  3. Where it comes from
  4. Why it matters
  5. What the research shows about microbes in our products
  6. What to expect
  7. Studies

What Elm Dirt does about solvents and VOCs

A solvent plume is engineered remediation work. It needs site characterization, an agency-approved work plan and a design, and our part fits inside that.

We rebuild the biology in the soil above and around the plume with living biologicals and compost, so the ground carries a large population of organisms with published research on these compounds. Soil and sediment biology does real work in breaking solvents down, and natural-attenuation studies hinge on whether that capability is there and active.

The two biological routes on this page need opposite conditions. Aerobic cometabolism needs air and something to feed on. Reductive dechlorination needs the oxygen gone and an electron donor. A plan states which zone is doing which. We work with local applicators, and an independent lab samples on a schedule for the breakdown products as well as the parent compound, since on this class the breakdown products are what decide success.

What it is

Chlorinated solvents are small organic molecules carrying chlorine atoms: trichloroethylene (TCE), perchloroethylene (PCE), carbon tetrachloride, 1,2-dichloroethane and vinyl chloride.

They are dense, so they sink below the water table. They are volatile, so they move as vapor into basements and crawlspaces. And they break down into one another. PCE degrades to TCE, TCE to dichloroethene, and dichloroethene to vinyl chloride, a known human carcinogen more dangerous than the compound it came from. A cleanup that stops halfway can leave a site worse off than before.

Where it comes from

  • Metal degreasing at machine shops, plating works and manufacturing plants
  • Dry cleaners, historically the most common urban source
  • Chemical manufacturing and storage
  • Derailments, where vinyl chloride is among the regulated cargoes
  • Landfills and disposal pits from before modern controls

Why it matters

Solvents reach groundwater faster than most contaminants and travel farther once they get there. Vapor can seep into occupied buildings a long way from the original release.

What the research shows about microbes in our products

Independent lab analysis (Biome Makers) identified these organisms in Elm Dirt products, and peer-reviewed research shows each can act on the compounds named.

Organism What the research documents
Desulfitobacterium dichloroeliminans Strips both chlorines off 1,2-dichloroethane in a single step, releasing ethene with no vinyl chloride formed, and it does this without needing to be pre-grown on the compound [1][2]. Tracked by qPCR through an in-ground bioaugmentation test at an industrial site in Belgium [3]
Pseudomonas stutzeri Carbon tetrachloride removal of 98 to 99.9 percent, sustained four years at full scale in a groundwater biocurtain [4]
Pseudomonas putida A strain of this species grows on vinyl chloride as its only source of carbon and energy [5][6]. Another breaks down TCE cometabolically through toluene dioxygenase [7]
Comamonas testosteroni Transforms TCE and all three dichloroethene isomers while feeding on phenol. Paired with a vinyl chloride degrader, a five-compound chloroethene mixture came down to near zero, vinyl chloride included [8]
Pseudomonas mendocina Toluene-4-monooxygenase cometabolism of TCE and chloroform [9]

At Schoolcraft, Michigan, a Pseudomonas stutzeri strain was injected into a contaminated aquifer to form a living barrier across the plume. It removed 98 to 99.9 percent of the carbon tetrachloride, held that for four years and treated roughly 18,600 cubic meters of groundwater [4]. It is the strongest field result in our library. It also took a characterized site, a selected strain, engineered delivery and years of monitoring.

Biology can attack chlorinated solvents by two routes, one that needs oxygen and one that runs without it. In aerobic cometabolism, broad enzymes attack solvents as a side reaction while the organism feeds on something else, such as toluene or phenol. In anaerobic reductive dechlorination, chlorine atoms are stripped off without oxygen, and this route can carry a site all the way to harmless ethene without stalling at vinyl chloride. Organisms in our products have published research on both.

What to expect

A biological route can create unwanted daughter products as easily as it removes the parent compound, since the enzyme that turns 1,2-dichloroethane into ethene also turns 1,1,2-trichloroethane into vinyl chloride [2]. The compounds present decide what a biological route produces, so sampling comes before treatment.

Anaerobic organisms need the oxygen gone while aerobic ones need air and a co-substrate, and a single patch of soil can’t offer both at once.

Solvent treatment runs for months to years, and an independent lab monitors the breakdown products the whole way through.

The plume itself needs an engineered design under an approved work plan, and our part is to support the soil system around it and bring disciplined monitoring.

Our soil-restoration pilot in East Palestine, Ohio sits in this kind of setting.

Studies

  1. De Wildeman S, Linthout G, Van Langenhove H, Verstraete W (2004). Complete lab-scale detoxification of groundwater containing 1,2-dichloroethane. Applied Microbiology and Biotechnology 63(5):609–612. doi:10.1007/s00253-003-1363-y
  2. Kunze C, Diekert G, Schubert T (2017). Subtle changes in the active site architecture untangled overlapping substrate ranges and mechanistic differences of two reductive dehalogenases. The FEBS Journal 284(20):3520–3535. doi:10.1111/febs.14258
  3. Maes A, Van Raemdonck H, Smith K, Ossieur W, et al. (2006). Transport and activity of Desulfitobacterium dichloroeliminans strain DCA1 during bioaugmentation of 1,2-DCA-contaminated groundwater. Environmental Science & Technology 40(17):5544–5552. doi:10.1021/es060953i
  4. Dybas MJ, et al. (2002). Development, operation, and long-term performance of a full-scale biocurtain utilizing bioaugmentation. Environmental Science & Technology 36(16):3635–3644. doi:10.1021/es0114557
  5. Danko AS, Luo M, Bagwell CE, Brigmon RL, Freedman DL (2004). Involvement of linear plasmids in aerobic biodegradation of vinyl chloride. Applied and Environmental Microbiology 70(10):6092–6097. doi:10.1128/AEM.70.10.6092-6097.2004
  6. Danko AS, Saski CA, Tomkins JP, Freedman DL (2006). Involvement of coenzyme M during aerobic biodegradation of vinyl chloride and ethene by Pseudomonas putida strain AJ and Ochrobactrum sp. strain TD. Applied and Environmental Microbiology 72(5):3756–3758. doi:10.1128/AEM.72.5.3756-3758.2006
  7. Wackett LP, Gibson DT (1988). Degradation of trichloroethylene by toluene dioxygenase in whole-cell studies with Pseudomonas putida F1. Applied and Environmental Microbiology 54(7):1703–1708. doi:10.1128/aem.54.7.1703-1708.1988
  8. Zalesak M, Ruzicka J, Vicha R, Dvorackova M (2021). Examining aerobic degradation of chloroethenes mixture in consortium composed of Comamonas testosteroni RF2 and Mycobacterium aurum L1. Chemosphere 269:128770. doi:10.1016/j.chemosphere.2020.128770
  9. McClay K, Fox BG, Steffan RJ (1996). Chloroform mineralization by toluene-oxidizing bacteria. Applied and Environmental Microbiology 62(8):2716–2722. doi:10.1128/aem.62.8.2716-2722.1996

Working on a site with chlorinated solvents & VOCs?

Send the location and any sampling results, and we'll tell you whether biology has a role there.

Start with your site details