ABSTRACT
BACKGROUND: Rapid industrialization and anthropogenic activities such as the unmanaged use of agro-chemicals, fossil fuel burning and dumping of sewage sludge have caused soils and waterways to be severely contaminated with heavy metals. Heavy metals are non-biodegradable and persist in the environment. Hence, remediation is required to avoid heavy metal leaching or mobilization into environmental segments and to facilitate their extraction. OBJECTIVES: The present work briefly outlines the environmental occurrence of heavy metals and strategies for using microorganisms for bioremediation processes as reported in the scientific literature. METHODS: Databases were searched from different libraries, including Google Scholar, Medline and Scopus. Observations across studies were then compared with the standards for discharge of environmental pollutants. DISCUSSION: Bioremediation employs microorganisms for removing heavy metals. Microorganisms have adopted different mechanisms for bioremediation. These mechanisms are unique in their specific requirements, advantages, and disadvantages, the success of which depends chiefly upon the kind of organisms and the contaminants involved in the process. CONCLUSIONS: Heavy metal pollution creates environmental stress for human beings, plants, animals and other organisms. A complete understanding of the process and various alternatives for remediation at different steps is needed to ensure effective and economic processes. COMPETING INTERESTS: The authors declare no competing financial interests.
ABSTRACT
Mycoremediation is one of the biotechniques that recruits fungi to remove toxic pollutants from environment in an efficient and economical manner. Mushrooms, macro-fungi, are among the nature's most important mycoremediators. Pleurotus species (also called oyster mushrooms) are considered to be the most popular and widely cultivated varieties worldwide and this might be attributed to their low production cost and higher yields. Apart from their nutritive and therapeutic properties, Pleurotus species have high biosorption potential due to their extensive biomass, i.e. mycelial production. The genus has been reported to accumulate high levels of heavy metals. The current state-of-the art review mainly summarises previous investigations carried out by researchers on different roles and mechanisms played by Pleurotus species on heavy metals mycoremediation.
ABSTRACT
BACKGROUND: Monumental progress has been made in the area of information and communication technology, leading to a tremendous increase in use of electronic equipment, especially computers and mobile phones. The expansion of production and consumption of electronic equipment along with its shorter life span has led to the generation of tremendous amounts of electronic waste (e-waste). In addition, there is a high level of trans-boundary movement of these devices as second-hand electronic equipment from developed countries, in the name of bridging the digital gap. OBJECTIVES: This paper reviews e-waste produced in India, its sources, composition, current management practices and their environmental and health implications. Fixing responsibility for waste disposal on producers, establishment of formal recycling facilities, and strict enforcement of legislation on e-waste are some of the options to address this rapidly growing problem. DISCUSSION: The exponential growth in production and consumption of electronic equipment has resulted in a surge of e-waste generation. Many electronic items contain hazardous substances including lead, mercury and cadmium. Informal recycling or disposing of such items pose serious threat to human health and the environment. CONCLUSIONS: Strict enforcement of waste disposal laws are needed along with the implementation of health assessment studies to mitigate inappropriate management of end-of-life electronic wastes in developing countries.
