Impact of activated carbon on the catabolism of (14)C-phenanthrene in soil

Activated carbon amendment to contaminated soil has been proposed as an alternative remediation strategy to the management of persistent organic pollutant in soils and sediments. The impact of varying concentrations (0%, 0.01%, 0.1% and 1.0%) of different types of AC on the development of phenanthrene catabolism in soil was investigated. Mineralisation of (14)C-phenanthrene was measured using respirometric assays. The increase in concentration of CB4, AQ5000 or CP1 in soil led to an increase in the length of the lag phases. Statistical analyses showed that the addition of increasing concentrations of AC to the soil significantly reduced (P < 0.05) the extent of (14)C-phenanthrene mineralisation. For example, for CB4-, AQ5000- and CP1-amended soils, the overall extent of (14)C-phenanthrene mineralisation reduced from 43.1% to 3.28%, 36.9% to 0.81% and 39.6% to 0.96%, respectively, after 120 days incubation. This study shows that the properties of AC, such as surface area, pore volume and particle size, are important factors in controlling the kinetics of (14)C-phenanthrene mineralisation in soil

Optimisation of XAD extraction methodology for the assessment of biodegradation potential of 14C-phenanthene in soil

This study investigated the use of a hydrophobic resin, amberlite XAD, as a tool for assessing the biodegradation potential of 14C-phenanthene in soil. The method was optimised in terms of soil/XAD ratio, shaking, extraction time and eluting solvent. The most effective method was then tested on selected XADs, and the performance compared with cyclodextrin (HP- β -CD) and dichloromethane (DCM) extractions suitability to predict phenanthrene biodegradation in soil over 100 d. Results showed that the optimum conditions for the XAD extraction technique are a 2:1 soil/XAD ratio, 100 rpm mixing for 22 h and elution using a DCM:methanol solution (1:1). Mineralisation of 14C-phenanthrene was accurately predicted by HP- β -CD ( r 2 = 0 . 990 , slope  =  0.953, intercept  =  1.374) and XAD-4 extractions ( r 2 = 0 . 989 , slope  =  0.820, intercept  =  6.567), while DCM overestimated the bioaccessibility of  14C-phenanthrene ( r 2 = 0 . 999 , slope  =  1.328, intercept  = − 49 . 507 ). This investigation showed that XAD extraction can be considered a suitable non-exhaustive technique for estimating biodegradability of phenanthrene in soil

Indigenous 14C-phenanthrene biodegradation in “pristine” woodland and grassland soils from Norway and the United Kingdom.

In this study, the indigenous microbial mineralisation of 14C-phenanthrene in seven background soils (four from Norwegian woodland and three from the UK (two grasslands and one woodland)) was investigated. ∑PAHs ranged from 16.39 to 285.54 ng g−1 dw soil. Lag phases (time before 14C-phenanthrene mineralisation reached 5%) were longer in all of the Norwegian soils and correlated positively with TOC, but negatively with ∑PAHs and phenanthrene degraders for all soils. 14C-phenanthrene mineralisation in the soils varied due to physicochemical properties. The results show that indigenous microorganisms can adapt to 14C-phenanthrene mineralisation following diffuse PAH contamination. Considering the potential of soil as a secondary PAH source, these findings highlight the important role of indigenous microflora in the processing of PAHs in the environment.N/

Assessment of PAH contaminated land:implementing a risk-based approach

Abstract Polycyclic aromatic hydrocarbons (PAHs) are amongst the most common ubiquitous anthropogenic pollutants of terrestrial ecosystems. There are currently multiple sources of PAHs in Nigeria and land use activities have been shown to alter the composition of PAHs and in some cases increase the fractions of carcinogenic and recalcitrant components. This report considers the implementation of a more specific risk based corrective action to abate threats caused by carcinogenic PAHs in eroded and degraded soils for prospective risk assessment and realistic decision-making. Bioremediation is promoted for degradation of PAHs in soils, but faces several limitations that question the effectiveness of the approach. This review provides insights into bioaccessibility and chemical activity assessment of PAHs as a procedure of risk assessment and the potential use of specially produced biochar designed for specific risk mitigation remedial action was also considered

Can Afro-Communitarianism Be Useful in Combating the Challenge of Human Interaction Posed by the COVID-19 Pandemic?

Can Afro-communitarianism serve as a viable ideology for addressing the human interaction challenge posed by the COVID-19 pandemic? The ongoing pandemic poses many challenges to the normal functioning of societies around the world. For example, it has caused problems ranging from social, economic, and political disruption to various forms of hardship, including pain, suffering, and millions of deaths. One problem that is not attracting sufficient attention is a disruption to human interaction that leads to isolation, depression, mental health, and emotional crises. This paper will investigate whether Afro-communitarianism can function as an ideological option for addressing this challenge. This ideology, in our opinion, can foster social integration and the type of informal solidarity that engenders emotionally helpful interactions among humans. We will also argue that Afro-communitarian orientation can overturn the individualistic tendencies that hamper efforts aimed at curtailing the spread of the coronavirus

Effects of pre-exposure on the indigenous biodegradation of 14 C-phenanthrene in Antarctic soils.

The aim of this study was to investigate the biodegradation of phenanthrene in five Antarctic soils over 150 days at various temperatures and under slurry conditions. The development of catabolic activity was measured over time (1, 30, 60, 150 days) by the addition of 14C-phenanthrene and measuring changes in the lag phases, rates and extents of 14C-phenanthrene degradation. As the temperature increased (4 °C, 12 °C, 22 °C, 22 °C slurry), the highest extents of 14C-phenanthrene mineralisation increased significantly (0.46%, 12.21%, 24.82%, 60.81%), respectively. This was due to changes in the water availability and 14C-phenanthrene dissolution in aqueous phase, thus enhancing bioaccessibility of the contaminant to indigenous microorganisms within the soil. High catabolic activities can develop in Antarctic soils where appropriate conditions are ensured. However, further studies are however needed to explore the changes in microbial community structure that occur at different incubation temperatures.N/