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<br />these herbicides in agricultural and non-
<br />agricultural uses.' Preliminary agricul-
<br />tural ttseresults indicate that the est®ated
<br />do~ar value of yield lass in affected crops
<br />and cost of alternative weed conhol ma-
<br />terials and metfiods combined may ,each
<br />mote than $1.5 billion per yeaz (32). The
<br />crops most severely affected include
<br />whea4 sugarcane, soybean, and peanuts,
<br />while the costs of weed control in pas[[[te
<br />and land in fallow would inaease mazk-
<br />edly. Addttiottal data are being evahtated
<br />on the impact of a baB of phenoxies in
<br />noncrop applications, where 2,4D is used
<br />extensively as a mixing partner for weed
<br />conarol in turf, forestry, and rightsoF way.
<br />CONCLUSION
<br />This review presents the framework for a
<br />weight-of-evidence analysis of the heahh
<br />significance of 2,4D in comparison with
<br />the compound's benefits. Available stud-
<br />iesshow that 2,4D is rapidly excreted and
<br />not metabolized m reactive intermediates.
<br />It does not possess chemical characte~is-
<br />tics linked with biological reactivity and
<br />does not produce genotoxic or neurologi-
<br />cal effects in animal systems. Results of
<br />animal s[[[ties do not suggest that 2,4D
<br />is carcinogenic, and epidemiology stud-
<br />ies have yielded inconsistent findings
<br />which have not demanstmrrd accuse-and-
<br />effec[ relationship. Last year aB expert
<br />EPA panel concluded the[ there was at
<br />most only `weak evidence" for an also-
<br />elation betwcen cancer and 2,4D.
<br />Of equal importance is that neural ex-
<br />posures m 2,4D today and in the future
<br />would be expected to be very limited
<br />based on more rigorous protective cloth-
<br />ing standards and reduced Ltbel applica-
<br />tion rates. Perhaps the World Health
<br />Organization provides the best perspec-
<br />tive on the health significance of 2,4D in
<br />its environmental health criteria review,
<br />which states that, "as faz as the general
<br />population is concerned, 2,4-D intake
<br />from any sourcz is negligible" (34).
<br />'iLe Nadooel Agriculwr+l Pesticide Impact
<br />Assessmtat Progtam (NAP[AP) 7'eehoiml
<br />Bulletia'Ibe Biologic and Ecwomic Assastoent
<br />of Ne Benefits of Phenoxy Hetbicidrs ie dfe
<br />United States mill be public6ed late in 1995.
<br />1. Agricultural Canada. 1989. 2,4-D
<br />Update. Food Ptoductitn and Tnspce-
<br />tion Branch, Pesticides Diroctorate,
<br />Information Secretariat. CAPCO
<br />(Canadian Association of Pesticide
<br />ConrrolOffitiaLs)Note: 89-01,1-12.
<br />2. Blair, A., and S.H. Zahm. 1992. Ag-
<br />ricultural health: pesticides and can-
<br />cer. Health & Environment Digest.
<br />6(5):1.
<br />3. Bramble, W.C., and W.R. Bums.
<br />1974. Along-term ecological study
<br />of game food and cover on a sprayed
<br />utility tightof-way. Purdue Univer-
<br />sity Bulletin No. 918:16.
<br />4. Burmeister, L.F. 1986. Review of
<br />Hoar, S., et al., Agricultural herbicide
<br />use and risk of lymphoma and soft
<br />tissue sazcoma. Commissioned by
<br />EPA. Urriversity of Iowa, Iowa City,
<br />I.4.
<br />5. Cantor, A.P., et al. 1992. Pesticides
<br />and other agriculttrral risk factors for
<br />non-Hodgkin's lymphoma among
<br />men in Iowa and Mrrmesota. Cancer
<br />Research. 52:2447-55.
<br />6. CAST. 1987. Perspectives on the
<br />safety of 2,4D. Comments from
<br />CAST, ISSN 0194-0096. Council for
<br />Agricultural Science and Technol-
<br />ogy, Ames, IA, 1-16.
<br />7. CCT. 1987. Expert penal report on
<br />carcinogenicity of 2,4D. Canadian
<br />Centre for Toxicology, Guelph,
<br />Ontario, Canada.
<br />8. Engler, R. 1992. Memormdum: List
<br />of chemicals evaluated for carcino-
<br />genic potential. Health Effects Divi-
<br />siodOPP, USEPA, Washington DC.
<br />9. EPA. 1988. Guidance for the
<br />reregistration of pesticide products
<br />containing 2,4~ichloropheooxyace-
<br />tic acid (2,4D) as the active ingredi-
<br />ent. Envvonmental Protection
<br />Agency, Office of Pesticides and
<br />Toxic Substances, O1Tice of Pesticide
<br />Programs, Washington DC. pp. 51-
<br />106.
<br />10. EPA. 1988. Notice: Proposed dcei-
<br />sion not to initiate a special review.
<br />Fed Reg. 53(56):9590-4.
<br />
<br />11. EPA. 1992. Lawrence E. Culleen let-
<br />ter to 2,4D registrants regarding ex-
<br />ptume redtrctian. Oct 30, 1992. pp.
<br />I-7.
<br />12. EPA. 1994. Ptn SAB report Asstss-
<br />ment of potential 2,4D carttinogenic-
<br />ity: Review of the epidemiological
<br />and other data oo potential careino-
<br />genicity oC 2,4D by the SAB/SAP
<br />Join[ COmmitrrP, Sciatica Advisory
<br />March 1994. FPA-SAB-EHC-94-005
<br />Environmental Protection Ageucy,
<br />Washington DC.
<br />13. Gorzinski, S.J., et al. 1987. Acute,
<br />pharmacokinetic, and subchronic
<br />toxicological studies of 2,4-dichloro-
<br />phenoxyacetic acid. Fund. Appl.
<br />Todcol. 9:42335.
<br />14. Hoar, S.K., et al. 1986. Agricultural
<br />herbicide use and risk of lymphoma
<br />and soft-tissue sarcoma. JAMA.
<br />?56(9):1141-7.
<br />I5. Ibrahim, M.A., et al. 1991. Weight
<br />of the evidence on the human carci-
<br />nogenicity of 2,4D. Environ Health
<br />Perspec. 96:213-22.
<br />16. Industry Task Force II on 2,4D Ro-
<br />search Data. Bo date. Unpublished re-
<br />sults of over 60 toxicology and 54
<br />envrronmental toxicology studies
<br />with 2,4D submitted to the U.S. EPA
<br />m support the reregistration of 2,4D.
<br />17. Jeffries, T.K., et al. 1995. 2,4-Di-
<br />chloropheuoxyacedc acid: Chronic
<br />roxicityloncogenicity study in
<br />Fischer 344 tats. Internal report of
<br />The Dow Chemical Company, Mid-
<br />land, MI.
<br />18. Johnson, R.A., e[ al. 1993. Dam on
<br />prior pesticide use collected from
<br />self- and proxy respondents. Epide-
<br />miology. 4:157-164.
<br />l9. Knepp, D., anti F. Schiller. 1992.
<br />Oral and dermal application of
<br />2,4dichlorophenoxyacedc acid so-
<br />dium and dime[hylamine salts to
<br />male tats: Investigations on absorp-
<br />tion and excretion as well as induc-
<br />tion of hepatic mixed-function
<br />oxidase activities. Arclt Toiicol.
<br />66(3)x70-174.
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