Biological remediation of polychlorinated biphenyls (PCB) in the environment by microorganisms and plants

Abstract

The environment is suffering severe contamination as a result of various uncontrolled activities of man and chemicals in the biosphere. This widespread contamination of air, soil and water by metals, chemicals and metalloids causes environmental concerns, which if left unchecked will be detrimental to man and other organisms. Biological methods for the cleaning of the environment especially our soil have been receiving increasing attention especially in the past two decades. Bacteria and fungi have been the natural detoxification agents for contaminants in the environment. Recently, research has shown that with the combination of plants and microorganism in the right proportions and technique, detoxification of environmental contaminants will produce a desirable and better result and most importantly our natural environment may not be affected as some of the processes are environmentally friendly. However, hydrophobic organic molecules such as polychlorinated biphenyls (PCBs) tend to be much less responsive to bioremediation strategies. The wide spread presence of this compounds and other persistent organic pollutants (POPs), that share common chemical, toxicological and environment properties continues to increase in the environment, even with the various measures taken to control its presence. This review focuses on the possible trends in the remediation of PCBs in the environment and the methodologies applied. It also compares plants remediation as well as microorganisms' degradation as biological detoxification agents of the compound. This will highlight the possible improvement measures on the combination of plants and microorganisms in bioremediation, thereby filling the gap left by the conventional methods of remediation with its limitations and disadvantages.

Evaluation of contamination levels of different types of composts and their suitability for usage in agriculture

“…The more chlorine atoms a molecule has, the more complex is its degradation process. Another important characteristic determining PCBs degradation is the placement of a chlorine atom in the molecule (Anyasi, Atagana, 2011). The obtained results correlate with the data of other authors, who investigated green waste compost, household biowaste compost and digestate compost obtained under anaerobic conditions (Brändli et al, 2008;Riedel, Marb, 2008).…”

Changes in bacterial diversity associated with bioremediation of used lubricating oil in tropical soils

“…Bioremediation is one such method and uses microorganisms and/or plants to transform or reduce environmental contaminant concentrations (Anyasi and Atagana 2011). Successful bioremediation treatments are dependent on multiple factors including the type and concentration of the contaminant, indigenous microbial population, temperature, oxygen, nutrients, and soil characteristics (Khan et al 2004).…”

Characterization of polychlorinated biphenyls in surface sediments of the North End Lake, Port Elizabeth, South Africa

“…Further, the highly chlorinated PCB congeners are more likely to be adsorbed to particulate material resulting in accumulation and deposition in the sediment. They have relatively low mobility and hence tend to remain closer to the contamination source, whereas lighter PCB congeners may be subject to microbial degradation and volatilisation (Piñeiro et al, 1996;Anyasi and Atagana (2011). The hydrophobicity which increases with molecular weight seems to be responsible for the stronger sorption on the organic matter of the sediment size fractions.…”