Aerobic conditions, in soils

Biodegradation t,/2 > 365 d under aerobic conditions in soil, and microbial degradation is accelerated by light (Tomlin 1994). 

Cyanuric acid has been classified as essentially nontoxic (acute and dermal), and nonirritating to skin and to the eyes 108,109 however, inhalation of dust, contact with eyes and ingestion should be avoided. Above 200 °C, cyanuric acid decomposes to the toxic isocyanuric acid. Cyanuric acid is biodegradable under aerobic conditions in soil and in aerated systems.110-112... 

Kurek E (2002) Microbial mobilization of metals from soil minerals under aerobic conditions. In Huang PM, Bollag J-M, Senesi N (eds) Interactions between soil particles and microorganisms. Impact on the terrestrial ecosystem, vol 8, IUPAC series on analytical and physical chemistry of environmental systems. Wiley, Chichester, UK, pp 189-225... 

Soil. Loehr and Matthews (1992) studied the degradation of phenol in different soils under aerobic conditions. In a slightly basic sandy loam (3.25% organic matter) and in acidic clay soil (<1.0% organic matter), the resultant degradation half-lives were 4.1 and 23 d, respectively. 

Haider, K.,Jagnow, G., Kohnen, R.. and Lim, S.U. Degradation of chlorinated benzenes, phenols, and cyclohexane derivatives by benzene- and phenol-utilizing bacteria under aerobic conditions, in Decomposition of Toxic and Nontoxic Organic Compounds in Soil Overcash. V.R., Ed. (Ann Arbor. MI Ann Arbor Science Publishers, 1981), pp. 207-223. 

Data on exposure and environmental fate are needed, not to determine toxicity, but to provide information that may be useful in the prediction of possible exposure in the event that the chemical is toxic. These tests are primarily useful for chemicals released into the environment such as pesticides, and they include the rate of breakdown under aerobic and anaerobic conditions in soils of various types, the rates of leaching into surface water from soils of various types, and the rate of movement toward groundwater. The effects of physical factors on degradation through photolysis and hydrolysis studies and the identification of the product formed can indicate the rate of loss of the hazardous chemical or the possible formation of hazardous degradation products. Tests for accumulation in plants and animals and movement within the ecosystem are considered in Section 21.7. 

Avermectins and the breakdown products are nearly insoluble in water and bind strongly to soil. Thus they have little mobility and are unlikely to leach into groundwater. Avermectins are rapidly degraded in soil, sensitive to rapid photodegradation. When applied to the soil surface, its soil half-life was about 1 week. Under dark, aerobic conditions, the soil half-life is somewhat extended (2 weeks to 2 months). Microbial degradation also contributes to rapid loss from soils. Avermectins are also rapidly degraded in water (half-life 12-24 h), principally due to photodegradation. 

Indole will mainly exist in the vapor phase and is degraded in the atmosphere by reaction with photo-chemically produced hydroxyl radicals, nitrate radicals, and ozone with estimated half-lives of 2-3 h, < 1 min, and 6 h, respectively. Indole is expected to readily biodegrade under both aerobic and anaerobic conditions in soil and water. Bioconcentration in aquatic organisms should be low, given an estimated bioconcentration factor value of 25. 

Propanil is rapidly metabolized under anaerobic and aerobic conditions in a water and soil matrix. It is... 

The degradation of [1JC]PBO, at a concentration of 10 mg L l, was investigated in a waler/sediment system (using a sandy loam soil, 2.5 cm deep) incubated under aerobic conditions in darkness for 30 days (Elsom, 1995a). Following application to the surface water. PBO partitioned into both sediment (60%) and water (40 ). where it was further degraded. The calculated DTW (loss of 5055 of the initial residue) in the system was 213 days. Both MDB... 

Kurek, E. (2002). Microbial mobilization of metals from soil minerals under aerobic conditions. In Interactions Between Soil Particles and Microorganisms Impact on the Terrestrial Ecosystem, ed. Huang, P. M., Bollag, J.-M., and Senesi, N., lUPAC Series on Analytical and Physical Chemistry of Environmental Systems, Vol. 8, Wiley, Chichester, West Sussex, England, 189-225. 

Abiotic degradation in other media has not been reported and most available publications are on biodegradation in aerobic conditions. In all of the biodegradation studies, however, the concentrations of SCCPs exceeded the maximum water solubility of SCCPs (0.975 mg L ). Therefore, it is assumed as a worst case scenario that SCCPs are not degraded in water, soil, sediments, or sewage sludge. 

Redox conditions in soils vary widely over short distances because O2 must diffuse through pores of various sizes and water-filled pores. In aerobic soils the interior of soil aggregates may be partially anaerobic. The change from oxygen sufficiency to deficiency can occur within a few millimeters. In wet soils, only the largest pores are open to gas diffusion from the atmosphere. 

Determination of the ultimate aerobic biodegradability in soil by measuring the oxygen demand in a respirometer or the amount of carbon dioxide evolved Determination of the degree of disintegration of plastic materials under simulated composting conditions in a laboratory-scale test... 

Simulation Tests Test results indicate rate of aerobic degradation under environmentally relevant conditions in soil, aquatic sediments, surface water, or a sewage treatment plant. Degradation rates determined by monitoring radiolabeled carbon or chemical analyses. 

Grima, S., Bellon Maurel, V., Sdvestre, F., Feuilloley, R., 2001. A new test method for determining biodegradation of plastic material under controlled aerobic conditions in a soil-simulation solid environment. J. Polym. Environ. 9, 39—48. 

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