Water biodegradability

Decane is readily degradable in fresh and saline waters. Biodegradation half-lives of decane in... 

Surface water biodegradation t,/2 < 20 d in water and sediment with flooded soils and terrestrial-aquatic model ecosystems (Muir 1991). 

Surface water biodegradation t,/2 = 0.46 d at 20°C by aerobic activated sludge or anaerobic microorganisms (Kawamoto Urano 1990)... 

Surface water biodegradation t,/, = 8 d in river water and ty, = 4.5 d in lake water (Vaishnav Babeu 1986, 1987 quoted, Howard 1993) and ty, = 4 d in Superior harbor waters (Vaishnav Babeu 1987). 

Ground water biodegradation t,/, = 32 d (Vaishnav Babeu 1986, 1987 quoted, Howard 1993) ... 

Surface water biodegradation ty, = 2.21 d in an acclimated shake flask COj evolution test (Sugatt et al. 1984) G 2 d to > 2 wk for aerobic biodegradation in water ty, = 3 d when incubated in dirty river water (Howard 1989) ... 

Surface water biodegradation ty, = 0.87 d in river water (Peterson Staples 2003)... 

Surface water biodegradation 4 to 5 wk in river water by namrally occurring, mixed microbial populations (Saeger Tucker 1976) ... 

Persistence in the soil is generally low (half-life under aerobic and anaerobic conditions is 21 and 68 days, respectively). In sterile soil, the half-life is almost 1 year. Azinphos-methyl adsorbs strongly to soil particles and has low solubility in water. Biodegradation and evaporation are the primary routes of elimination from soil but azinphos-methyl is also degraded by ultraviolet light. Degradation is more rapid at higher temperatures. Azinphos-methyl has a short half-life in surface waters (2 days). Hydrolysis is more prominent under alkaline conditions but the compound is relatively stable in water below pH 10. The half-life on crops is 3-5 days under normal conditions. 

If released to acclimated water, biodegradation would be the dominant fate process (half-life 2.5-4 days). BPA may adsorb extensively to suspended solids and sediments (Kqc values range from 314 to 1524), and it may photolyze in the presence of sunlight. BPA is not expected to bioaccumulate significantly in aquatic organisms (BCF 5-68), volatilize, or undergo chemical hydrolysis. 

Pentachloronitrobenzene has an estimated half-life of 1.8 days in water. It is more stable in acidic and neutral conditions. Volatilization, adsorption, and sedimentation as detritus are the major processes responsible for the rapid decrease in quintozene in water. Biodegradation and photolysis are not relevant pathways. In soils, volatilization and biodegradation are important pathways, with anaerobic conditions being more favorable for the degradation. 

FIGURE 27.13 Extracted ion chromatograms for C2-naphthalenes (ion 156, at 14 days, a), C3-naphthalenes (ion 170, at 28 days, b), Ci-fluorenes (ion 180, at 14 and 28 days, c), Ci-phenanthrenes (ion 192, at 14 and 28 days, d), and Ci-dibenzothiophenes (ion 198, at 14 and 28 days, e) in the source sterile control PB oil and the corresponding positive controls under standard fresh water biodegradation conditions. The circled peaks indicate the characteristic changes in distribution within isomers that were preferentially altered by biodegradation and/or co-metabolic oxidation. 

Type Form Anionic/70% Liquid in propylene glycol water Biodegradability Complete Flash Point, F >200... 

Sodium dicyclohexyl sulfosucoinate Anionic/85% Pellets in water Biodegradability Complete... 

---