The use of 2,2′-bipyridine in the production of the herbicide diquat may result in its direct release into the environment or through various waste streams. If released into air, the estimated vapor pressure at 25 °C is 1.3X10-5 mm Hg, indicating that 2,2′-bipyridine will be present in both the vapor and particulate phases in the ambient atmosphere. Gas-phase 2,2′-bipyridine will degrade in the atmosphere by reaction with photochemically generated hydroxyl radicals; the half-life of this reaction in air is estimated to be 12.5 days. The particulate phase 2,2′-bipyridine will be removed from the atmosphere by wet and dry deposition. If released into soil, 2,2′-bipyridine is expected to have moderate mobility based on an estimated Koc of 160. Based on estimated Henry’s, volatilization from moist soil surfaces is not expected to be a significant fate process. The s-law constant is 5.4X10-10 atm-cu m/mole. If released to the estimated Koc, 2,2′-bipyridine is expected to adsorb into suspended solids and sediments, but cations are expected to adsorb strongly. Based on estimated Henry’s Law constants for this compound, volatilization from the water surface is not expected to be a significant fate process. An estimated BCF of 3 indicates a low potential for bioconcentration in aquatic organisms. 2,2′-bipyridine is slowly oxidized by photochemically generated hydroxyl radicals in aqueous solution with a half-life of approximately 129 days. Skin contact with the compound in workplaces where 2,2′-bipyridine is produced or used may result in occupational exposure to 2,2′-bipyridine.
Use the structure estimation method (1). This corresponds to an atmospheric half-life of approximately 12 days and an atmospheric concentration of 5X10+5 hydroxyl radicals/cm3 (1). The rate constant for the reaction of 2,2′-bipyridine with photochemically generated hydroxyl radicals in water was measured to be 6.2X10+9 M-1 sec-1 at 21 °C and a pH of 9.3(2), which corresponds to 1X10 Water half-life of about 129 days at a hydroxyl radical concentration of -17 M (3). Due to the lack of hydrolyzable functional groups, 2,2′-bipyridine is not expected to undergo hydrolysis in the environment (4). No data are available to assess the potential for direct photolysis of this compound.