Rates of biodegradation of sorbed chemicals are usually lower in soil than in aqueous systems, in part because sorption reduces the availability of the chemical to microorganisms. Biodegradation, sorption, and diffusion occur simultaneously and are tightly coupled. In soil, the rate of biodegradation is a function of a chemical's diffusion coefficient, sorption partition coefficient, the distan...

Aerobic biodegradation behavior of nonylphenol monopropoxyethoxylates was investigated in two tests with different inocula-sewage sludge and river water. Both primary biodegradation and formation of different biodegradation intermediates were studied. Primary biodegradation of nonylphenol monopropoxyethoxylates was relatively fast and complete with the sewage sludge as the inoculum. On the othe...

Compound-specific isotope analysis has the potential to distinguish physical from biological attenuation processes in the subsurface. In this study, carbon and hydrogen isotopic fractionation effects during biodegradation of benzene under anaerobic conditions with different terminal-electron-accepting processes are reported for the first time. Different enrichment factors (epsilon ) for carbon ...

Hotspots and coldspots of concentration and biodegradation of polycyclic aromatic hydrocarbons (PAHs) marginally overlapped at the 0.5-100 m scale in a creosote contaminated soil in southern Sweden, suggesting that concentration and biodegradation had little spatial co-variation. Biodegradation was substantial and its spatial variability considerable and highly irregular, but it had no spatial ...

Well-established biodegradation tests use biogenously evolved carbon dioxide (CO(2)) as an analytical parameter to determine the ultimate biodegradability of substances. A newly developed analytical technique based on the continuous online measurement of conductivity showed its suitability over other techniques. It could be demonstrated that the method met all criteria of established biodegrada...

Perchlorate (ClO4) has been detected in some states in the U.S and become an environmental concern since the late 1990’s. Perchlorate properties, contamination, and health effects were introduced in this paper. Perchlorate biodegradation degradation were introduced and summarized. According to recent studies, perchlorate respiring bacteria are present in natural environments, providing possibil...

Density of catalytic organisms can determine the biodegradation capacity and specific biodegradation rate (SBR). A new index, biodegradation capacity utilization (BCU, %), was developed for estimating the extent of actual biodegradation of a gas compound over the full capacity. Three methanotrophic cultures were serially diluted (1-1/25), and methane SBR and BCU were measured. Consistently, bio...

Regulatory evaluations of commercial chemicals in Canada, the United States, the European Union, and other countries aim to identify biodegradation rates of chemicals in natural soils and sediments. However, commonly used biodegradation testing methods are limited in their capacity to determine biodegradation rates under natural environmental conditions. As a result, widely varying biodegradati...

The ultimate biodegradation of the commercial products nonylphenol ethoxylates (NPE9), octylphenol ethoxylates (OPE9), and their biodegradation intermediates, NPE1.5, OPE1.5, NP, and OP, was measured using conventional methods. The extent of biodegradation was also determined by gas chromatography/mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC) analysis of metabolite...

Interest in the biodegradation mechanisms and environmental fate of polycyclic aromatic hydrocarbons (PAHs) is prompted by their ubiquitous distribution and their potentially deleterious effects on human health. PAHs constitute a large and diverse class of organic compounds and are generally described as molecules which consist of three or more fused aromatic rings in various structural configu...