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

Contaminant group

Pesticides & Herbicides

Organophosphates, chlorophenoxy herbicides and legacy organochlorines behave very differently in soil. Biology handles some of them well, and the breakdown products deserve as much attention as the parent chemical.

What biology does
Breaks down
Microbes in our products
P. putida, C. necator, B. diminuta and 1 more
Shows up at
Agricultural Land, Flood Sediment
Diagram: Pesticides & Herbicides, microbial action, outcomeResidues of specific agricultural compounds, each with its own chemistry. Hydrolase and oxygenase enzymes split particular bonds, compound by compound. Breakdown: in the research. Microbes in our products are studied against specific pesticides and herbicides, and each compound is checked on its own. Binding: in the research. Residues bind to clay and organic matter, which keeps them near the surface where soil biology is most active.01 CONTAMINANT02 MICROBIAL ACTION03 OUTCOME Pesticides & HerbicidesResidues of specific agriculturalcompounds, each with its ownchemistry.Microbial actionHydrolase and oxygenase enzymessplit particular bonds, compoundby compound.CO2H2OIN THE RESEARCHBreakdownMicrobes in our productsare studied againstspecific pesticides andherbicides, and eachcompound is checked onits own.IN THE RESEARCHBindingResidues bind to clay andorganic matter, whichkeeps them near thesurface where soilbiology is most active.Diagram: Pesticides & Herbicides, microbial action, outcomeResidues of specific agricultural compounds, each with its own chemistry. Hydrolase and oxygenase enzymes split particular bonds, compound by compound. Breakdown: in the research. Microbes in our products are studied against specific pesticides and herbicides, and each compound is checked on its own. Binding: in the research. Residues bind to clay and organic matter, which keeps them near the surface where soil biology is most active.01 CONTAMINANTPesticides & HerbicidesResidues of specific agriculturalcompounds, each with its ownchemistry.02 MICROBIAL ACTION Microbial actionHydrolase and oxygenase enzymes splitparticular bonds, compound bycompound.03 OUTCOMECO2H2OIN THE RESEARCHBreakdownMicrobes in our products arestudied against specificpesticides and herbicides,and each compound is checkedon its own.IN THE RESEARCHBindingResidues bind to clay andorganic matter, which keepsthem near the surface wheresoil biology is most active.
Fig. 1How biology acts on pesticides & herbicides, 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 pesticide residue
  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 pesticide residue

Pesticides are built to be biologically active, and soil organisms have been adapting to them since the 1940s [1], and our work starts from there.

We apply living biologicals and Class A compost so the ground carries more organisms, more organic matter and more root activity. A residue then has more chances to meet an enzyme that can break it. Our products also carry species with published research on the two best-understood pathways on this page: organophosphate hydrolase, and the tfd route for chlorophenoxy herbicides.

Sampling covers breakdown products along with the parent compound. With chlorpyrifos, the metabolite TCP is toxic, persistent and antimicrobial enough to slow the organisms working on the parent. Some soil bacteria go on to mineralize TCP, but that second step doesn’t happen on its own schedule [1]. A report showing the parent gone, with no metabolite data, leaves the question open. We work through local applicators, and an independent lab samples on a schedule.

What it is

“Pesticide” covers several chemical families that behave very differently in soil.

  • Organophosphates such as parathion, chlorpyrifos and diazinon are moderately persistent, and the best-characterized pesticide-destroying enzyme known breaks them down.
  • Chlorophenoxy herbicides such as 2,4-D are widely applied and well studied for microbial breakdown.
  • Organochlorines such as DDT and aldrin are mostly banned and extremely persistent, and a published review reports DDT field half-lives of up to 30 years in soil, and 365 days for aldrin [1].
  • Carbamates, pyrethroids, neonicotinoids and urea herbicides, each with its own persistence.

Where it comes from

  • Agricultural application, current and historic
  • Former orchards, where lead arsenate residue often sits alongside the organics
  • Mixing, loading and rinse areas, with concentrations far above treated fields
  • Storage buildings, co-ops and abandoned chemical dealerships
  • Runoff and drift collecting in low ground and drainage ways

About 3 billion kilograms of pesticide go on worldwide each year, across more than 500 compounds [1].

Why it matters

Organochlorines build up in fat and last for decades. Organophosphates are acutely toxic to the nervous system. Landowners worry about groundwater, residue in produce, and soil that stays toxic in high-concentration spots.

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 listed.

Organism Target What the research documents
Brevundimonas diminuta Organophosphates Produces organophosphate hydrolase, which cuts the central triester bond in one step with water and removes the toxic action. The plasmid was identified in 1982, the gene cloned in 1988, and the species can grow using an organophosphate insecticide as its phosphate source [2][3][4]
Cupriavidus necator 2,4-D, chlorophenoxy herbicides The tfd pathway strips the side chain, removes the chlorines and opens the ring. Carbon-tracing work followed labelled herbicide carbon into the bacterium’s own fatty acids, confirming it was eaten rather than merely transformed [5][6]
Pseudomonas putida Chlorpyrifos Degradation in repeated-batch and continuous systems [7]
Variovorax paradoxus Linuron Hydrolysis via the aniline route [8]

A published review names Bacillus, Micrococcus, Arthrobacter, Corynebacterium, Flavobacterium, Pseudomonas and Rhodococcus, plus the fungi Penicillium and Trichoderma, among the groups with high pesticide-degrading activity [1]. Several of those genera are in our products.

What to expect

DDT and the other organochlorines resist microbial attack, which is why they last for decades, and we make no claim on them.

A broken-down parent compound doesn’t mean the soil is safe, so our sampling plans include the breakdown products.

Responsive compounds can come down in weeks to months under good conditions, while legacy organochlorines take years or show no real change, and independent lab testing confirms the outcome either way.

Studies

  1. Armenova N, Tsigoriyna L, Arsov A, Petrov K, Petrova P (2023). Microbial detoxification of residual pesticides in fermented foods: current status and prospects. Foods 12(6):1163. doi:10.3390/foods12061163 (Peer-reviewed review, open access. Its laboratory data are from food fermentation, not soil; cited here for pesticide classes, persistence and the organophosphate hydrolysis mechanism.)
  2. McDaniel CS, Harper LL, Wild JR (1988). Cloning and sequencing of a plasmid-borne gene (opd) encoding a phosphotriesterase. Journal of Bacteriology 170(5):2306–2311. doi:10.1128/jb.170.5.2306-2311.1988
  3. Serdar CM, Gibson DT, Munnecke DM, Lancaster JH (1982). Plasmid involvement in parathion hydrolysis by Pseudomonas diminuta. Applied and Environmental Microbiology 44(1):246–249. doi:10.1128/aem.44.1.246-249.1982
  4. Parthasarathy S, et al. (2016). Organophosphate hydrolase is a lipoprotein and interacts with Pi-specific transport system to facilitate growth of Brevundimonas diminuta using OP insecticide as source of phosphate. Journal of Biological Chemistry 291(14):7774–7785. doi:10.1074/jbc.M116.715110
  5. Lerch TZ, et al. (2007). Tracing 2,4-D metabolism in Cupriavidus necator JMP134 with ¹³C-labelling technique and fatty acid profiling. Journal of Microbiological Methods 71(2):162–174. doi:10.1016/j.mimet.2007.08.003
  6. Kumar A, Trefault N, Olaniran AO (2016). Microbial degradation of 2,4-dichlorophenoxyacetic acid: insight into the enzymes and catabolic genes involved, their regulation and biotechnological implications. Critical Reviews in Microbiology 42(2):194–208. doi:10.3109/1040841X.2014.917068
  7. Pradeep V, Subbaiah UM (2015). Repeated batch and continuous degradation of chlorpyrifos by Pseudomonas putida. Journal of Environmental Science and Health, Part B 50(4):346–360. doi:10.1080/03601234.2015.1000180
  8. Dejonghe W, et al. (2003). Synergistic degradation of linuron by a bacterial consortium and isolation of a single linuron-degrading Variovorax strain. Applied and Environmental Microbiology 69(3):1532–1541. doi:10.1128/AEM.69.3.1532-1541.2003

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