Profile 5 Levels out of CFC-11, CFC-several and you may CFC-113 from inside the shut ampoules away from Withlacoochee River-water of southern-eastern Georgia indicating destruction out-of CFC-11 and you may CFC-113 and you will obvious balances regarding CFC-twelve (regarding Plummer et al., 1998b).
CFCs were not degraded inside ampoules of your river water stored below white in the room-temperature. Growth of algae try present in these ampoules which most likely suffered cardio standards (Plummer mais aussi al., 1998b).
Cook mais aussi al. (1995) showed nearly over destruction out of CFC-eleven and you may stability off CFC-a dozen within the a great sulphate-cutting sand aquifer near Sturgeon Falls, Ontario, Canada. Around the fresh new groundwater many years according to CFC-several arranged better into the seen breadth of your mid-1960s step 3 H bomb height. Under marine, sulphate-reducing requirements when you look at the an excellent Norwegian fjord, Shapiro ainsi que al. (1997) discover rapid destruction away from CFC-11, and you can, inside uncertainties of your specifications, CFC-12 destruction could not had been over 1/600 that CFC-11. The latest half-lives getting CFC-eleven degradation during the sulphate-cutting, natural rich seawater is 0.step one ± 0.02 age and much more smaller than you to discover by Make mais aussi al. (1995) of 0.9 to at least one.seven many years.
Oster (1996) claimed degradation regarding CFC-eleven and CFC-a dozen in different (almost certainly methanogenic, however, generally unspecified) anoxic environments, with price out of CFC-11 degradation whenever ten-flex that CFC-a dozen
The presence of sulphate (and nitrate) in anaerobic environments slows the rates of dehalogenation reactions (Mohn and Tiedje, 1992; Sylvestre et al., 1997) by competing with highly halogenated aliphatic compounds as terminal electron acceptors. Inhibition of dehalogenation by sulphate may explain the persistence of CFC-12 in sulphate-reducing environments (as in Cook et al., 1995, Shapiro et al., 1997, and Plummer et al., 1998a,b) where dissolved sulphate is still present, and more rapid degradation of CFC-12 in methanogenic environments (Deipser and Stegmann, 1997; Oster et al., 1996) where sulphate concentrations are usually very low. Parks et al. (1995) reported complete removal of CFC-11 and CFC-12 under methanogenic conditions in the Memphis (sand) aquifer, south-west Tennessee (1.3 mg L -1 CH4, 7.3 mg L -1 SO4 2- , 5.3 mg L -1 Fe 2+ ). The measured tritium activity of 13.8 TU indicated post-bomb water that would otherwise contain easily measurable concentrations of CFCs. Shapiro et al. (1998) also found significant degradation of CFC-11 and CFC-12 under methanogenic conditions in a buried-valley aquifer near Dayton, Ohio. Fluvial and glacial drift deposits often contain particulate organic carbon and are low in sulphate. Such environments are usually methanogenic, and degradation of CFCs appears to be rapid.
During the natural environment brand new electron donor might be some form of smaller carbon dioxide such as mixed normal carbon dioxide, lignite, or another variety of particulate all-natural carbon dioxide included about sediment or water column. These days it is not possible examine sheer rates of degradation from a single environment otherwise laboratory reactor to another due to variability in many points as well as abundance and diversity regarding micro-bacteria, availability of substrate, all-natural constitution, and you may exposure regarding you can easily inhibitors.
Sorption
Like microbial degradation, sorption is another process that can remove CFCs from groundwater, leaving the impression of apparently older age and lower groundwater velocities. Cook et al. (1995) observed uptake 
of CFC-113 relative to CFC-12 and 3 H at the Sturgeon Falls site, Ontario, Canada. The vertical profiles of CFC-12 and tritium could be modelled with a recharge rate of approximately 130 mm yr -1 and were apparently not affected by sorption or degradation. The agreement in transport of CFC-12 and 3 H was so strong that, if sorption of CFC-12 were occurring, the solid-liquid partition coefficient, Kd, must be less than 0.03 (retardation factor 3 H at Sturgeon Falls. Most of the uptake of CFC-113 occurred in the aerobic upper 4 m of the water column, suggesting sorption of CFC-113, rather than microbial degradation (Cook et al., 1995). The CFC-113 profile indicates a Kd value of 0.09-0.14 (retardation factor 1.4-1.7) for CFC-113 in the sand aquifer, which contained, on average, 0.03% organic carbon.