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Biphenyl

Biphenyl. By Ashley Register. Overview. Structure, Chemical & Physical Properties Uses and Applications Production History Mode of Entry Chemical Reactivity and Speciation Toxicity to Aquatic Life Biochemical Metabolism Bibliography. Properties. 1,1’-biphenyl, diphenyl, phenyl benzene

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Biphenyl

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  1. Biphenyl By Ashley Register

  2. Overview • Structure, Chemical & Physical Properties • Uses and Applications • Production History • Mode of Entry • Chemical Reactivity and Speciation • Toxicity to Aquatic Life • Biochemical Metabolism • Bibliography

  3. Properties • 1,1’-biphenyl, diphenyl, phenyl benzene • Chemical and Physical Properties: • Kow: 4.09 • Water Solubility: 7.1 mg/L at 25oC • Henry’s Law Constant: 3E-4 atm m3/mol

  4. Hazard Classification • Classifed as: • EPA: • Class D carcinogen (not involved in human carcinogenesis) • Non-teratogenic • EU: • Irritant (Xi) • Dangerous for the environment (N)

  5. Uses and Applications • Dye Carrier for Textile dying • Intermediate for PCB’s and PBB’s • Fungicide for citrus fruits • Major component of Heat Transfer Fluids

  6. Production History • Designated for testing in 1982 because 700 million lbs/yr were being produced (Rand) • US Producers as of 1994: • Chevron Corporation (Baytown, TX) • Koch Chemical Company (Corpus Christi, TX) • Monsanto Chemical Company (Anniston, AL) • Sybron Chemicals Company (Wellford, SC)

  7. Mode of Entry into Aquatic Environment • Wastewater effluents • From textile mills that use it as a dye carrier • From industrial processes • Leaking heat exchangers • Volatilization and sorption are important

  8. Chemical Reactivity and Speciation • Biphenyl tends to partition into the sediment • Soil sorption coefficients: • mean value of 4230 • Indicates that biphenyl will be practically immobile in sediment • But even this effect is minimal, since the majority of biphenyl is volatilized.

  9. Toxicity to Aquatic Life • Acute toxicity: • Values as low as 0.36 mg/L (daphnids) and 1.3 mg/L (rainbow trout). • LC50 (96h): • Bluegill (L. macrochirus) - 4.7 mg/L • Sheepshead minnow - 4.6 mg/L • Fathead minnow - 6 mg/L

  10. Toxicity to Aquatic Life • Chronic Toxicity: • Done in daphnids and rainbow trout • Daphnids: 275 mg/L • NOEC: 0.17mg/L • Trout: 230 mg/L • Indicative of Low Chronic Toxicity • Studies with bacteria indicate no mutagenic potential

  11. Toxic Effects Noted • In the aquatic environment: • Inhibition of growth • Noted only in algae (Chlorella) • Slight inhibition at 1 mg/L • Complete inhibition at 10 mg/L • Inhibition of food intake • Observed in Mytilus edulis • EC50 observed after 40 min of 0.3 mg/L • Molecular mode of Toxicity: • unknown

  12. Mode of Entry • Biphenyl enters an organism through: • Diet (accumulates in plants) • Since it is lipid soluble, tends to partition into adipocytes

  13. Biochemical Metabolism • Soil: • Biodegredation • S. cerevisiae, Streptomyces, Achromobacter, Pseudomonas putida, Oscillatoria, gram negative bacteria. • Oxidize via CytP450 to 2,3 dihydroxybiphenyl • Fungi metabolize biphenyl to 4-hydroxy- or 2-hydroxy- biphenyl and 4,4’-dihydroxybiphenyl • Biochemical Metabolism

  14. Biochemical Metabolism • Water: • Microbial degradation • Aromatic hydroxylation to 2-, 3-, and 4- dihydroxybiphenyl • Activated sludge (74% in 14d) • Anaerobic digester (100% in 7d) • Aerated Lagoon (100% in 8h) • Retention Pond (100% in 96h) • Domestic Wastewater (79% in 5d) • Industrial Wastewater (87% in 24h) • Photolysis • Irradiation with 250 nm light underwent 50% degradation in 40 hours.

  15. Biochemical Metabolism • Biota: • Bioconcentration Factors: • Rainbow Trout - 436 L/kg • Algae - 540 L/kg • Orfe - 282 L/kg • Suggests a moderate potential for accumulation in aquatic organisms • Kow indicates an affinity for lipids

  16. Defense Mechanisms • Phase I and II metabolism • Defense mechanisms are not well developed for Biphenyl due to: • Low concentrations being present in water and sediment

  17. Conclusion • Biphenyl has a high acute toxicity but low chronic toxicity • Tends to volatilize • Low affinity for water • Virtually immobile in sediment • Quickly metabolized

  18. References • Rand, G.M. Fundamentals of Aquatic Toxicology: Effects, Environmental Fate, and Risk Assessment. 2nd Edition. CRC Press, New York, NY, 1995. • Concise International Chemical Assessment Document (CICAD) • www.inchem.org/documents/cicads/cicads/cicad06.htm • International Program on Chemical Safety (IPCS) • www.inchem.org • National Pollution Inventory, Australian Government. • www. Npi.gov.au/database/substance-info/profiles/14.html

  19. References • OSHA • www.osha.gov • Hazardous Substances Data Bank (HSDB) • http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB • US Environmental Protection Agency (EPA) • www.epa.gov • TSCA Compliance Guide • www.tsca.info

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