Class: Dioxins
Chemical Name: Molecular Makeup:

Chlorodibenzofurans (CDF)


Polychlorinated Dibenzo-p-dioxins (CDFs) are a type of chlorinated hydrocarbon centered around C4H4O2 with 135 isomers. They are often referred to as “dioxins” along with CDDs. They are undesired by=products of industrial chemical production, incineration, paper mill bleaching, and photolysis of PCBs, PCDE, and polychlorinated benzenes. [1]

Transport Vectors:
CDFs deposit rapidly, persisting in soil and sediment as well as the fat of exposed organisms. They also transport through air readily with the particulate phase and larger isomers all possessing a lifetime of > 10 days. Levels in unpolluted rural air and soil are generally too low to measure with concentrations at dump sites thousands to millions of times higher. [1]

Sample Concentration Levels

Abiotic Media:

Water (ppt)


Air  (pg/m3)


Drinking Water: n/d
TetraCDFs, kraft pulp mill effluent: <0.01 – 4,100
Chloralkali bleaching mill: <52,000 2,3,7,8-tetraCDF
81,000 ppt (octaCDF)
Rainwater, Indiana: <0.6 – 5.7
Dorset, CN:
.2 – 6.0 [2][3]

Uncontaminated Elk River soil high: 753.2
Ontario incineration facility high: 1821.2 [5]
PCP Landfill: 251,000 [6]

Bridgeport, CT:
2.563 [10]
Toronto, CN: 1.108 [11]
US & Canada Average: 4.2 [12]
Dayton, OH Waste Incinerator: 35.37
Dayton, OH rural: <0.31 [13]

Six American Rivers, Sediment: 5 – 97 ppt [1]
Uncontaminated Lake (Pepin) sediment: <1 ppt
Lake Michigan sediment: 24 ppt [4]

  Biotic Media:

Fish/Sea Life (wet wt., ppt)

Mussels & Crustacean Life (ppt)

Food (ppt wet)

NY Striped Bass Meat: 157.2 [8]
Lake Ontario composite (tetra & pentaCDFs only): 2,357 [9]

Blue Crab Meat: 257.1
Blue Crab Pancreas: 12,122.7 [8]

NY Supermarket Meat: .14 - 7.0
.07 - 1.14
Dairy: .3 – 5 [7]

Whole Blood ppt Lipid

At Risk Groups (blood serum, ppt)

Adipose Tissue, average ppt

Breastmilk, ppt lipid, 8 congeners

USA: 91.7
Germany: 101
Dong Nai, Vietnam:
132.5 [1]

Incinerator Workers: 102.8
Control Group: 47.0 [18]

Sweden: 85.9
Germany: 84.9
Canada: 127.9
146.6 [1]

USA: 29.35 [14]
Japan: 41.3 [15]
Sweden: 46.6 [16]
Germany: 53.5 [17]

Health effects:


  1. Agency for Toxic Substances and Disease Registry. 1994. Toxicological profile for chlorinated chlorodibenzofurans. Atlanta: US Department of Health and Human Services.
  2. Eitzer BD, Hites RA. 1989b. Polychlorinated dibenzo-p-dioxins and dibenzofurans in the ambient atmosphere of Bloomington, Indiana. Environmental Science and Technology 23:1389-1395.
  3. Reid NW, Orr DB, Shackleton MN, et al. 1990. Monitoring dioxins and dibenzofurans in precipitation in Ontario. Chemosphere 20:1467-1472.
  4. Smith LM, Schwartz TR, Feltz K, et al. 1990. Determination and occurrence of AHH-active polychlorinated-biphenyls, 2,3,7,8-tetrachloro-para-dioxin and 2,3,7,8-tetrachlorodibenzofuran in Lake Michigan sediment and biota. The question of their relative toxicological significance. Chemosphere 21:1063-1085.
  5. McLaughlin DL, Pearson RG, Clement RE. 1989. Concentrations of chlorinated dibenzo-p-dioxins (CDD) and dibenzofurans (CDF) in soil from the vicinity of a large refuse incinerator in Hamilton Ontario Canada. Chemosphere 18:851-854.
  6. Hagenmaier H, Berchtold A. 1986. Analysis of waste from production of sodium pentachlorophenolate for polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF)Chemosphere 15: 1991-1994.
  7. Schecter A, Startin J, Wright C, et al. 1993. Dioxin levels in food from the United States with estimated daily intake. In: Fiedler H, Frank H, Otto H, et al., eds. Organohalogen compounds, Vol. 13. Vienna: Federal Environmental Agency, 93-96.
  8. Rappe C, Kjeller LO, Kulp SE, et al. 1991. Levels, profile and pattern of PCDDs and PCDFs in samples related to the production and use of chlorine. Chemosphere 23:1629-1636.
  9. Stalling DL, Norstrom RJ, Smith LM, et al. 1985. Patterns of PCDD, and PCB contamination in Great Lakes fish and birds and their characterization by principal components analysis. Chemosphere14:627-643.
  10. Hunt GT, Maisel BE. 1990. Atmospheric PCDDs/PCDFs in wintertime in a northeastern U.S. urban coastal environment. Chemosphere 20:1455-1462.
  11. Steer P, Tashiro C, Clement R, et al. 1990. Ambient air sampling of polychlorinated dibenzo-p-dioxins and dibenzofurans in Ontario: Preliminary results. Chemosphere 20: 143 1- 1437.
  12. Waddell D, Chittim B, Clement R, et al. 1990. Database of PCDD/PCDF levels in ambient air and in samples related to the pulp and paper industry. Chemosphere 20:1463-1466.
  13. Tiernan TO, Wage1 DJ, Garrett JH, et al. 1989. Laboratory and field tests to demonstrate the efficacy of KPEG reagent for detoxification of hazardous wastes containing polychlorinated dibenzop-dioxins (PCDD) and dibenzofurans (PCDF) and soils contaminated with such chemical wastes. Chemosphere 18:835-841.
  14. Schecter A. 1991. Dioxins and related chemicals in humans and in the environment. In: Banbury report 35: Biological basis for risk assessment of dioxins and related compounds. Cold Spring Harbor Laboratory, 169-214.
  15. Rappe C. 1992. Dietary exposure and human levels of PCDDs and PCDFs. Chemosphere 25:231-234.
  16. Rappe C. 1987. Global distribution of polychlorinated dioxins and dibenzofurans. ACS Symposium Series no. 338, 20-33.
  17. Fürst P, Fiirst C, Wilmers K. 1992. PCDDs and PCDFs in human milk-statistical evaluation of a 6-year survey. Chemosphere 25:1029-1038.
  18. Schecter AJ, Malkin R, Papke 0, et al. 1991~. Dioxin levels in blood of municipal incinerator workers. Med Sci Res 19:331-332.