by Murray Thompson


Bifenthrin: Mobile through vapor phase

Dr. Lee Chow Yang

Tunneling Responses of the Asian Subterranean Termite, Coptotermes gestroi in Termiticide-Treated Sand

(Isoptera: Rhinotermitidae)


Boon-Hoi, Yeoh & Chow-Yang, Lee)

Sociobiology Vol. 50, No. 2, 2007

At: I found the below-quoted info by Dr. Lee Chow Yang (  Many people typically repeat (regurgitate) orthodox and institutionalized information on bifenthrin which seems to mean that this info must not be questioned or significantly updated.  Ad nauseum it is stated that, magically I guess according to whatever original data became institutionalized: bifenthrin doesn't move in soil after application.  I beg to differ with the following research.

Termites were killed in bifenthrin treatments, and this suggested the movement of the chemical from treated into untreated sections.  Su & Scheffrahn (1990) reported the movement of a  pyrethroid (tralomethrin) from treated sand to the agar layer in their experiment against R. flavipes, causing high mortalities even though the termites did not reach the treated area.  Many other researchers also reported the role of vapor phase in their experiments.  Ebeling & Pence (1958) noticed that the vapour phase of chlorinated hydrocarbons had penetrated into areas beyond the treated soil and was killing the termites.  Isoborneol has also shown a high rate of evaporation in sand (Blaske et al. 2003).  Although bifenthrin has low volatility when applied on dry soil, it possesses a higher migration potential in wetter conditions (Fecko 1999).  The movement of the termiticide (and emulsifier) was probably facilitated by water solubility (Smith & Rust 1990; 1991) and vapor pressure (Su et al. 1982; Smith & Rust 1990; 1991).  When the vapor pressure is high enough, some of the termites might have satisfactory amounts of toxicant deposited on the cuticle.  Penetration of the toxicant through the cuticle will slowly affect the termites without direct termiticide contact (Su et al. 1982; Smith & Rust 1991).  This may explain the death of the termites in the untreated section. (page 464); accessed: August 2009)


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If vapor pressure affects termites in untreated areas, then surely that means bifenthrin will migrate through soil and then into a concrete slab?  Could this info mean then that all parts of the biflex/talstar mixture are available for transport via vapor pressure gradients?

Many continuously declare the impossibility of an external chemical barrier Biflex termiticide treatment ever intersecting people inside a residence.  The repetition of fixed statements like these seems to have become a 'religion'.

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Bifenthrin is NOT immobile, as well as being quite persistent

Note:; Published in J Environ Qual 34:836-841 (2005).  This journal article seems to also support (in a different way I think) that Bifenthrin is NOT immobile, as well as being quite persistent.

J. Gana,*, S. J. Leea, W. P. Liub, D. L. Haverc and J. N. Kabashimac

a Department of Environmental Sciences, University of California, Riverside, CA 92521

b Department of Environmental Sciences, Zhejiang University, Hangzhou, China, 310029

c University of California Corporative Extension-Orange County, Irvine, CA 92626

* Corresponding author (

Received for publication June 23, 2004. Pyrethroids are commonly used insecticides in both agricultural and urban environments. Recent studies showed that surface runoff facilitated transport of pyrethroids to surface streams, probably by sediment movement.  Sediment contamination by pyrethroids is of concern due to their wide-spectrum aquatic toxicity.  In this study, we characterized the spatial distribution and persistence of bifenthrin [BF; (2-methyl(1,1'-biphenyl)-3-yl)methyl 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate] and permethrin [PM; 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid (3-phenoxyphenyl) methyl ester] in the sediment along a260-m runoff path.  Residues of BF and PM were significantly enriched in the eroded sediment, and the magnitude of enrichment was proportional to the downstream distance.  At 145 m from the sedimentation pond, BF was enriched by >25 times, while PM isomers were enriched by >3.5 times.  Pesticide enrichment along the runoff path coincided with enrichment of organic carbon and clay fractions in the sediment, as well as increases in adsorption coefficient Kd, suggesting that the runoff flow caused selective transport of organic matter and chemical-rich fine particles.  Long persistence was observed for BF under both aerobic and anaerobic conditions, and the half-life ranged from 8 to 17 mo at 20°C.  The long persistence was probably caused by the strong pesticide adsorption to the solid phase.  The significant enrichment, along with the prolonged persistence, suggests that movement of pyrethroids to the surface water may be caused predominantly by the chemically rich fine particles.  It is therefore important to understand the fate of sediment-borne pyrethroids and devise mitigation strategies to reduce offsite movement of fine sediment. (Accessed: August 2009)

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General Health Problems Associated With A Chemical Barrier Termite Treatment

The Department of Pesticide Regulation (DPR) in the US has completed a human health risk assessment (attached) on the use of the active ingredient bifenthrin as a subterranean termiticide (BiflexB TC) (emphasis mine).

Using current toxicity and exposure data, DPR finds that significant adverse effects could occur as a result of the use of BiflexB TC during postconstruction termiticide treatments.

 Source:; accessed: 22 April 2010

Biflex is:

1.  moderately acutely toxic
2.  a possible CARCINOGEN
3.  a suspected endocrine disruptor
4.  a highly toxic developmental or reproductive toxin
5.  acutely toxic to aquatic life

accessed: 22 April 2010

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As well, (Journal of UOEH, 2004 Dec 1;26(4):423-30.) seems to imply that Bifenthrin can cause cancer:

Goto S, Asada S, Fushiwaki Y, Mori Y, Tanaka N, Umeda M, Nakajima D, Takeda K.

Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki 305-8506, Japan.

The tumor-promoting activities of 5 commercial compounds used in termiticides were measured by a cell-transformation assay employing Bhas 42 cells. Their initiating activities were also measured by the microsuspension assay employing S. typhimurium TA98 and TA100 strains. The results of the transformation assay confirmed the tumor-promoting activities of fenitrothion, silafluofen and bifenthrin. Furthermore, the mutagenicity of S-421 and fenitrothion were also confirmed. Consideration of 2-stage carcinogenesis suggests that concurrent use of and long-term exposure to these compounds that have tumor-promoting and initiator activity, and compounds exhibiting either type of activity individually should be avoided as much as possible.

PMID: 15624354 [PubMed - indexed for MEDLINE] (Accessed: August 2009)

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Can Pesticide Move From the Soil into the Concrete Slab Under Your Unit?

Though fairly impervious to water movement, concrete is easily penetrated by vapors and solvents.  It is also prone to cracking.  For these reasons, the Environmental Protection Agency (EPA) believes that concrete alone may not provide an effective barrier to pesticide movement and has proposed that concrete in pesticide secondary containment structures be sealed or coated to reduce its permeability.  

Broder, M.F. [Agricultural Engineer] & Nguyen, D.T. [Corrosion Specialist] 1995 [online]. ‘INTRODUCTION’ in Coating Concrete Secondary Containment Structures Exposed to Agrichemicals. Land and Water Sciences Environmental Research Center, Muscle Shoals, Alabama 35662, June 1995, Tennessee Valley Authority. Accessed: August 2009.  Downloaded from:;jsessionid=9B60667EE878CBC7004A31B58ED998B6?purl=/236249-iW80zX/webviewable/.

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Chemical Diffusion Can Do Almost Anything!

…it is only recently that it has been generally recognized that there is a second contaminant transport process which will occur even through a very low hydraulic conductivity clay liner: that process is chemical diffusion…  diffusion may be the dominant contaminant transport mechanism in a well-constructed clay liner.  Furthermore, contaminants can escape from a waste disposal site, by diffusion through a liner, even if water flow in the liner is into the landfill.

Rowe, R.K. 1994, ‘Diffusive transport of pollutants through clay liners’, in Landfilling of Waste: Barriers, eds, T.H. Christensen, R. Cossu & R. Stagmann.  E. & F.N. Spon, London, UK, page 219.

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Other Research

Note that: provides info on Bifenthrin not usually found elsewhere.

The magic doctrine that everyone seems to have embraced is that the Bifenthrin binds to the soil and doesn't move.  Probably this is a convenience in terms of painting a rosy picture supporting the theory of no human intersection (and poisoning) and no environmental impact through immobility.

Further note:

"Characterizing Exposures to Nonpersistent Pesticides during Pregnancy and Early Childhood in the National Children’s Study..." (

"Pesticide loadings of select organophosphate and pyrethroid pesticides in urban public housing" (

"Reconstructing population exposures to environmental chemicals from biomarkers: Challenges and opportunities" (

"Pesticides and their Metabolites in the Homes and Urine of Farmworker Children Living in the Salinas Valley, CA" (

Note: "Environmental Exposure to Chemicals Through Dermal Contact" ( seems to support that voc/pyrethroid enters via the mucosa.

"PESTICIDES AND AUSTRALIAN INDOOR AIR QUALITY" ($File/env_indoorair.pdf#page=76).  Notes on page 77:

Environmental persistence of pesticides usually increases within indoor environments compared with natural or outdoor environments because of less exposure to direct sunlight, lower moisture and reduced microbiological activity.  Among chemical types or classes, the natural pyrethrins have a low persistence while persistence tends to increase from synthetic pyrethroids, carbamates, organophosphorus insecticides to organochlorines and inorganics such as arsenic trioxide or boron compounds.  However, persistence may vary between and within chemical classes and is also influenced by the nature of the indoor environment (e.g. increased bifenthrin and chlorpyriphos persistence under slabs).

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Comparison of risks from outdoor and indoor exposure to toxic chemicals

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DURSBAN TC: Air sampling results revealed elevated levels of volatile organic compounds (VOCs)

New York State Pesticide Poisoning Registry Report 1998

A PCC reported a family who relocated to a hotel, due to concern about remaining in their Dursban TC-treated home.  A termite application to the foundation had been performed earlier in the month.  The family initially received information on environmental testing labs from the NYSDOH Environmental Helpline.  They requested NYSDOH assistance for additional investigation of the application and resulting home contamination.  NYSPPR staff contacted the county health department on their behalf.  NYSDOH staff obtained the cooperation of the regional NYSDEC office for a joint investigation.  Staff advised the family on the handling of toys exposed to the pesticide and referred them to a NYSDOH affiliated clinic for medical follow-up.  

NYSDOH Bureau of Toxic Substance Assessment (BTSA) toxicology staff provided health effects information to the family.  BTSA staff made arrangements for analysis of air sampling results from the home to be conducted by the NYSDOH Wadsworth Laboratory.  Sampling results revealed elevated levels of volatile organic compounds (VOCs) in the home and several aromatic hydrocarbons.  The hydrocarbon pattern was a close match to that of other homes known to have Dursban TC contamination.  

The elevated VOCs may have been from the petroleum carrier of the pesticide.  The recommendation was made that remediation of the contamination in the home be conducted.  (Note - In June 2000, the EPA announced a ban on most home and garden uses of Dursban due to concerns about health risks.)
(Accessed: August 2009)

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VOCs & Termiticides Easily Enter Buildings

I note: that negative pressures allow VOCs and termiticides to enter buildings.  And page 189 of this document describes the persistence of even banned pesticide from previously termite-treated soil!



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