Flavobacterium. On the contrary, Klecka and Maier (1985)

reported that PCP degradation was inhibited at much lower

concentrations (800-1600 ug/1). Watanabe (1973a, 1973b)

examined PCP degradation in soil perfused with 40 ppm of PCP

and observed, after an eight day lag period during which

essentially no degradation occurred, chloride ion liberation

was initiated, and was complete within three weeks.

Subsequent additions of PCP were degraded more rapidly with

no lag period. Most of these degradation studies were

conducted under aerobic conditions. Boyd and Shelton

(1984), Smith and Novak (1987), and Ehrlich et al. (1982)

demonstrated that chlorophenols can also be degraded

anaerobically. However, rates of anaerobic degradation for

most organic contaminants are significantly slower than

those under aerobic conditions (Delfino and Miles, 1985),

and the anaerobic reductive dechlorination of PCP seemed to

stop at 3,5-dichlorophenol (Mikesell and Boyd, 1985).

 Increased chlorination of the phenolic compounds

increased stability to oxidation and enzymatic degradation

(Cserjesi, 1967), therefore, highly chlorinated phenols tend

to be more resistant to degradation.

 Many factors can influence the rate of biodegradation,

such as temperature, genus of the microorganisms, nutrients,

electron acceptor, pH, soil matrix, chemical concentration

of the compounds, and enzymes.


 Temperature. Although biodegradation can occur over a

wide range of temperatures, temperature greatly influences