Soil Biodegradability

In March 2012, no international standards existed which defined specifications for soil biodegradahility. Over several years, CEN made a big effort to develop a standard but a consensus could not be reached. The main reason was a disagreement on the possibility for a weathering pretreatment step in which polymers would first be exposed to light, temperature and moisture. 

In general, for soil, it can be noted that disintegration is largely determined by the intended use. For some applications, the plastic product should preferably disintegrate after a few months, while for other applications the product should remain intact for much longer. Consequently, many experts share the opinion that disintegration requirements should not be included in a soil standard. 

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Sediment desorption t,/2 = 42.4 d from sediment under conditions mimicking marine disposal (Zhang et al. 2000). Soil biodegradation rate constant k = 0.0024 d with t,/2 = 294 d for Kidman sandy loam soil, and k = 0.0033 d with t,/2 = 211 d for McLaurin sandy loam soil (Park et al. 1990) ... 

Environmental Fate. Di-/ -oct Iphthalate partitions primarily to soils and sediment upon release to the environment. The compound is expected to be strongly sorbed to soil and sediment particulates therefore, it should have limited mobility (EPA 1979, 1992c). Biodegradation half-lives of 1-4 weeks have been estimated for aerobic surface waters and soils. Biodegradation also takes place in sediments half-lives under anaerobic conditions have been estimated to range from of 6 months to 1 year (Howard et al. 1991). The compound may also undergo photolysis in surface waters (estimated half-life of 144 days) and photooxidation in the atmosphere (estimated half-life of about 5-45 hours) (Howard et al. 1991). Di-n-octylphthalate may persist in sediments as a result of its limited rate of biotransformation and preferential partitioning to this medium. 

Soil. Biodegradation is not expected to be significant in removing l,2-dibromo-3-chloro-propane. In aerobic soil columns, no degradation was observed after 25 d (Wilson et ah, 1981). The reported half-life in soil is 6 months (Jury et ah, 1987). 

Biological. 1-Naphthylamine added to three different soils was incubated in the dark at 23 °C under a carbon dioxide-free atmosphere. After 308 d, 16.6 to 30.7% of the 1-naphthylamine added to soil biodegraded to carbon dioxide (Graved et al., 1986). Li and Lee (1999) investigated the reaction of 10 mL of 7 mM 1-naphthylamine with 4 g of a Chalmers soil (pH 6.5, 11.1% sand, 72.8% silt, 16.0% clay). After 120 h, the soil was washed with acetonitrile and the extractant analyzed using GC/MS. The primary transformation product was a dimer tentatively identified as TV-(4-aminonaphthyl)-1-naphthylamine. The investigators hypothesized that the formation of this compound and two other unidentified dimers was catalyzed by minerals present in the soil. 

Table IV> Descriptions of Three Soil Biodegradation Studies Involving Use of Herbicide Orange...

The contaminant 2,3,7,8-TCDD has a long persistence time In soils (years) and may be a major consideration In the use of soil biodegradation as a disposal option for "unwanted" phenoxy herbicides or TCDD-contamlnated chemical wastes. 

Soil biodegradation tests were done by taking a sandy loam as the source of the soil micro-organisms. All polymer samples were sieved through ASTM sieves and all the samples except poly-e-caprolactone, had a particle diameter between 90 and 53 pm, Poly-e-caprolactone sample was prepared dissolving a commercially... 

Briglia, M., Nurmiaho-Lassila, E.L., Vallini, G. Salkinoja-Salonen, M. (1990). The survival of pentachlorophenol-degrading Rhodococcus chlorophenolicus and Flavobacterium sp. in natural soil. Biodegradation, 1, 273-81. 

Webb, O.F., T.J. Phelps, P.R. Bienkowski, P.M. Digrazia, G.D. Reed, B. Applegate, D.C. White, and G.S. Sayler. 1991. Development of a differential volume reactor system for soil biodegradation studies. Appl. Biochem. Biotechnol. 28-9(SPR) 5-19. 

Rouchaud, J., F. Gustin, O. Cappelen, and N.D. Mouraux (1994). Pig slurry and cow manure affect on atrazine and metolachlor soil biodegradation in maize. Bull. Environ. Contam. Toxicol., 52 568-573. 

Soil t,/2 = 72-7584 h, based on soil persistence and soil biodegradation studies (Bollag et al. 1978 Medvedev Davidov 1981 selected, Howard et al. 1991). 

Soil biodegradation t,/2 = 100 d from screening model calculations (Jury et al. 1984, 1987a,b 1990 Jury Ghodrati 1989 quoted, Montgomery 1993) selected field t,/2 = 82 d (Wauchope et al. 1992 Hornsby et al. 1996). 

Atagana, H. I., Haynes, R. J. Wallis, F. M. (2003). Optimization of soil physical and chemical conditions for the bioremediation of creosote-contaminated soil. Biodegradation, 14, 297-307. 

Capotorti, G., Digianvincenzo, P., Cesti, P., Bernard , A. GugUelmetti, G. (2004). Pyrene and benzo[a]pyrene metabolism by an Aspergillus terreiit strain isolated from a polycyclic aromatic hydrocarbons polluted soil. Biodegradation, 15, 79-85. 

TCP s low water solubility and high adsorption to particulates causes adsorption onto river or lake sediment and soil. Biodegradation in river water is rapid, almost complete within 5 days. Abiotic degradation is slower with a half-life of 96 days. BCFs of 165-2768 were measured for several fish species in the laboratory using radiolabelled TCP. Radioactivity was lost rapidly on cessation of exposure, depuration half-lives ranged between 25.8 and 90 hours. 

Allen, B. Wu, J. Doan, H. Inactivation of fungi associated with barley grain by gaseous ozone. J. Environ. Sci. Health 2003, B5.S (5), 617-630. Nam, K. Kukor, J.J. Combined ozonation and biodegradation for remediation of mixtures of polycyclic aromatic hydrocarbons in soil. Biodegradation 2000, 11, 1-9. 

Tiedje, J Michigan State Microbial ecology of soil and University, Crop and Soil biodegradation Sciences East Lansina. Michiaan U.S. Department of Agriculture, Cooperative State Research Service... 

BIOLOGICAL PROPERTIES Koc 22-118 expected to leach if released to soil biodegradation in soil possible can be detected in water by EPA Method 601 inert gas purge followed by gas chromatography with halide specific detection, or EPA Method 624 gas chromatography plus mass spectrometry... 

BIOLOGICAL PROPERTIES slightly mobile if released to soil slight tendeficy to sorb to sediments, suspended solids, and biota if released to soil biodegradation data are inconsistent aerobic half-life 4 weeks-6 months anaerobic half-life 2-13 days ground water half-life 2 days-12 months... 

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