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
Kow indicates highly lipid soluble (confirmed by low water solubility) and has potential for sorption into particulate matter
Henry’s law constant indicates chemical could undergo volitalization. Estimated volatilization t1/2 of 4.3 hours

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)
Tested under section 4 of TSCA

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
T 1/2 in water is 20 days
As mentioned earlier, the Henry constant indicates potential volatilazation

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) mg/L
Sheepshead minnow mg/L
Fathead minnow - 6 mg/L
HIGHLY toxic to aquatic life

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
Values greater than 100 mg/L indicate low chronic toxicity
Daphnids are most sensitive species

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
My sources have lots of info on the interaction with rats and rabbits if you need more information.
As mentioned before, adsorption into the soil and degredation are expected to drastically reduce the bioavailability of biphenyl. Therefore, it is of minor importance to aquatic organisms.

12. Mode of Entry Biphenyl enters an organism through:
Diet (accumulates in plants)
Since it is lipid soluble, tends to partition into adipocytes
Since biphenyl has a higher probability of entering the atmosphere and being air born than it does of becoming part of the water, bioaccumulation and biomagnification is of minor importance (CICAD)
Also, biphenyl is rapidly metabolized by bacterium and most species, so the effect is minimal

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 L/kg
Algae L/kg
Orfe L/kg
Suggests a moderate potential for accumulation in aquatic organisms
Kow indicates an affinity for lipids
Bioconcentration factor is the concentration of a particular chemical in a tissue per concentration of chemical in water (reported as L/kg). This physical property characterizes the accumulation of pollutants through chemical partitioning from the aqueous phase into an organic phase, such as the gill of a fish.
Moderate Potential 1000>BCF>250

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
Since biphenyl tends to volatilize, it rarely interacts with the aquatic environment. When it does, bacterium tend to metabolize biphenyl before it impacts higher organisms. Therefore, comprehensive defense is unnecessary.
Also, when biphenyl is encountered, it is rapidly metabolized and excreted.

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
Acute toxicity because it is usually not something they are exposed to and when they are, it is typically in small amounts.

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)
International Program on Chemical Safety (IPCS)
National Pollution Inventory, Australian Government.
www. Npi.gov.au/database/substance-info/profiles/14.html

19. References OSHA Hazardous Substances Data Bank (HSDB)
Hazardous Substances Data Bank (HSDB)
US Environmental Protection Agency (EPA)
TSCA Compliance Guide