Effect of Environmental Factors on the Degradation of 2,6-Dichlorophenol in Soil

Abstract

Chlorinated phenols (CP) are frequently found as harmful soil contaminants. Depending on the environment, CP may persist for extended periods of time. The influence of environmental factors on the degradation of 2,6-dichlorophenol (2,6-DCP) in unsaturated soil was examined using Ralstonia basilensis RK1 as inoculum for bioaugmentation. The disappearance of 2,6-DCP in soil microcosms was caused by bacterial mineralization. This was proved using U-14C-labeled 2,6-DCP. After 5 days of incubation, 61% of the initial activity was detected as 14CO2, while only 20% of the radioactivity remained in the soil, and 2,6-DCP was not detected. The relative importance of individual factors and possible two-factor interactions was assessed using a fractional-factorial experimental design. The following individual factors were identified as important: 2,6-DCP concentration, temperature, inoculum size, and the presence of an additional substrate. The strongest factorial interaction was observed between bacterial inoculation and 2,6-DCP concentration. For practical reasons, the influence of oxygen, organic matter, and the age of the contamination were not included in the factorial design; however, these factors were analyzed separately and found to significantly affect the biodegradation of 2,6-DCP. The findings of this study are important for the design of bioremediation techniques as well as the prediction of natural attenuation.

Effects of inorganic electrolyte anions on enrichment of Cu(II) ions with aminated Fe3O4/graphene oxide: Cu(II) speciation prediction and surface charge measurement

“…It has advantages over more standard methods in those instances where the important variables are not known or are many, and it also allows codependencies among experimental variables to be tested statistically (Aziz et al, 2011). In order to find the relative importance of individual background anions on Cu(II) adsorption and identify important interactions between pairs of anions (Steinle et al, 2000), FFD experiments were conducted in aqueous solution in the presence of six selected species with concentrations of different levels, and the results are demonstrated in Table 1. As shown in Table 1, the adsorption capacity of AMGO for Cu(II) ions in the system without background anions (Run 17) was 30.94 mg g À1 .…”

New Approaches for Bioaugmentation as a Remediation Technology

“…3 The abiotic stresses may include fluctuations or extremes in temperature, water content, pH, and nutrient availability, along with potentially toxic pollutant levels in contaminated soil. 221,243 In addition, the added microorganisms almost always face competition from indigenous organisms for limited nutrients, along with antagonistic interactions including antibiotic production by competing organisms, and predation by protozoa and bacteriophages.…”

Microbial degradation of disodium terephthalate by Rhodococcus sp. 9-003

“…9-003 was faster than that those of previous reports [8,9]. The degradation rate slowed down after 96 h, this fact is probably related to the formation of intermediate degraded products and the temporary accumulation in culture medium under high concentration of DT [21,22]. Furthermore, the increasing in pH during the biodegradation can cause an inhibitory effect [2], and after maintaining the pH at 7.5 using phosphate potassium Table 1 Characteristics of strain 9-003. buffer with low concentration of DT, complete degradation can be observed.…”