Nano Particles and Their Mode of Action in Environment

Nano particles are particles that exist on a nanometer scale. Nanoparticles exist in our surrounding either naturally or created by human activities. As per Commission of European Union (2011), a nano-object needs only one of its characteristic dimensions to be in the range of 1-100nm to be classed as a nanoparticle even if its other dimensions are outside that range. Nanoparticles have revolutionized the world through the introduction of a unique class of material and consumer products in many fields due to production of innovative materials and devices. Despite their unique benefits and utility in daily activities, this could result in undesirable changes in the environment and affect the workplace. Carbon-based nanoparticles, oxides of metals, and natural inorganic compounds can have biological effects on the environment and human health. This chapter deals with the nanoparticles and their mode of action in the environment.

Metal Hyperaccumulator Plants and Environmental Pollution

During evolutionary history of life on Earth, different life forms have undergone harsh environmental conditions. Plants have evolved multiple life forms and some of the specialist pioneer plants have the ability to colonize in hostile environmental conditions. Some plant taxa have the ability to accumulate high concentrations of potentially toxic trace elements (Ni, Zn, Cd, Se, As, Mn, Co, Cu, Pb, Sb, Tl) in their biomass. In some of these, taxa concentration of trace elements exceeds the concentration of macronutrients (e.g., Ca, K). Furthermore, metal hyperaccumulation is strongly associated with enhanced ability of these plants to detoxify the accumulated metal in the tissues. Such hyperaccumulation property has been reported in a total of approximately 500 Angiosperm species. This ability of the plants can be used for pollutant stabilization, extraction, degradation, or volatilization. The present chapter discusses heavy metals uptake mechanisms by plants and the potential of phytoremediation technique on treating heavy metal contaminated sides.

Bioremediation and Phytoremediation

This chapter explains the overview of bioremediation; soil remediation and Polycyclic Aromatic Hydrocarbon (PAH); bioremediation and ecosystem services; oil-contaminated soil, motor oil-contaminated soil, and petroleum-contaminated soil during bioremediation process; the overview of phytoremediation; the strategies and issues of phytoremediation; and phytoremediation and Plant Growth Promoting Bacteria (PGPB). Bioremediation is one of the safest methods to effectively manage contaminated waste. Without chemicals, bioremediation allows the contaminated waste to be recycled in environmental settings. Phytoremediation applies many types of plants to remove, stabilize, and destroy the contaminants in the soil and groundwater. The chapter argues that bioremediation and phytoremediation are the green technologies that can help remove contaminants from natural resources and are effective on the remediation of contaminated sites.

Mechanisms of Action of Nanoparticles in Living Systems

Nanoparticles are being formed continuously in processes like mineralization, natural calamities, and geological recycling of matter and present naturally in the environment. In the recent past, nanoparticles and their applications have become an extensive topic of research. Application of nanomaterials in different industries will surely enhance the chances of discharge of nanoparticles into the environment. So, a number of studies have been performed to explore the mode of action of nanoparticles on living organisms and their surroundings. The most reported modes of action of nanoparticles are antimicrobial activity, ROS-induced cytotoxicity, genotoxicity, plant growth promotion, etc. It has been successfully demonstrated that actions of nanoparticles are governed by their size, shape, dose, and concentration. However, a complete mechanism of action of nanoparticles has not been known. The present chapter focuses on the highlights of the mechanisms behind the mode of action of nanoparticles in plants and microorganisms.

Microbial Mineral Dissolution and Environmental Disasters

Microorganisms play very important role in elemental and mineral chemistry on earth surface. Along with the major biogeochemical cycles such as Carbon, Nitrogen, Sulphur and Phosphorus, which are crucially involved in thermodynamic balances in earth system, microbes are also involved in trace metal cycling. The organic carbon sustaining the indigenous microbial communities critically controls these microbial processes. A large number of the microbial communities are able to form a wide variety minerals, of which many have only biogenic origin and cannot be formed inorganically. Microbes also play a critical role in dissolution of minerals; a process which not only helps in soil formation and the transport of nutrients to higher trophic levels, but can also have many important industrial roles. Thus, in these metabolic activities, microorganisms contribute to the geological phenomenon of the transformation of metals and minerals. This chapter focuses on the role of various microbial metabolic processes that are involved in mineralization and mineral dissolution and the consequences involved with it.

Mushroom Crop in Agricultural Waste Cleanup

The environment is a life support system and it significantly influences the living organisms and their genes. Decomposers and microorganisms play a major role in maintaining the sustainability of the environment by converting toxic products into a mineralized form and maintaining the nutrient cycle. It is estimated that 62% of the 22 million tons of surplus rice straw is burnt in the field every year and contributes significantly to the black carbon emission from biomass burning. This alarming situation calls for a sustainable approach in crop residue management. Mushroom cultivation offers one such approach. Mushroom farms can act as disposal sites of agriculture residue and at the same time produce quality protein to meet the increasing protein demand. The macro fungi can play a major role in synthesis of non-toxic metal nano-particles from their salts and degradation of diverse crop residues through various enzymes present in them such as ligninases, cellulases, and laccases. Their role also extends to degrading the pesticides and persisting chemicals. This chapter explains the recent advances in mushrooms for effective crop residue utilization.

Impact of Hazardous Waste Material on Environment and Their Management Strategies

Hazardous waste has emerged as an issue of major concern that has negative impact both on human health as well as on the environment. Hazardous and infectious agents are handled in daily routine in biomedical laboratories. Their effects are increasing continuously in the environment. Hazardous waste includes solid, liquid, sharp and pathological waste. Workers in hospitals and health care, agricultural and fishing occupations are at particular risk of exposure to hazardous biological agents. Recently, more systematic and strict steps have taken by the Indian government regarding the public concern to prevent the proliferation of hazardous waste and its improper disposal. However, management of waste are still not well promoted. So, to intercept the build-up of biohazards into the environment, waste from biohazardous operations must be disposed or treated appropriately in a special way and it also intends to create awareness amongst the personnel involved in these sectors to develop and implement hazardous waste management and mitigation strategies.

Green Chemistry

Our environment needs to be protected from ever-increasing chemical pollution. Advances in science and technology can address the challenges of global environmental sustainability, which includes the release of persistent organic pollutants, climate change, and bioaccumulation of contaminants, endocrine disruption and ozone depletion. Achieving sustainability requires an intricate balance among resource use, economic growth and environmental impact. Green chemistry is a growing field of research where pollution is reduced by designing and developing chemical products/process addresses. Many of these are concerned by combining the critical elements of environmental improvement, economic competitiveness and social responsibility. In this chapter the scope for the development of green chemistry and the beneficial aspects have been discussed stressing future research.

Biodegradation of Natural and Synthetic Polymer

Polymer contamination with the advent of fast industrialization has become one of the serious threat to the natural environment. Due to lack of proper knowledge, poor waste management practice and unavailability of potential microbial strains, preference toward the biodegradable manmade and natural polymers. The prevalent occurrence of synthetic polymers is related to industrialization and domestic practices which affect the marine and terrestrial ecosystems. Scientific approaches exploited for polymer degradation include physical, chemical and biological treatments. Among them, biodegradation serves as eco-friendly approach to remediate polluted environment using living organisms. In this chapter biodegradation of natural (cellulose, hemicelluloses and lignin), synthetic (polyurethane, polyethylene succinate, polycaprolactone, polyvinyl alcohol and polyethylene) polymers and associated factors that influence the polymer biodegradation process have been discussed.

Role of Organic Soil Amendments in Controlling Ground Water Pollution Due to Pesticides

In soil, pesticide residues are subjected to various transformations and transportation processes. Leaching is one of the major transportation processes responsible for ground water contamination. Organic amendments used in agriculture are known to improve the physico-chemical properties of soil at low cost and are regarded as one of the most suitable technologies for sustainable agriculture. These amendments play an important role in the retention of pesticides because of increased adsorption of these chemicals on soil. Sorption of pesticides which are weak acids or bases, is influenced by soil pH because they assume a positive or negative charge, or no charge depending on the pH. Leaching of such pesticides to ground water can be prevented to a great extent by mixing of organic amendments to soil because they enhance the ability of pesticide retention on soil and or promote their microbial degradation as well during in situ decomposition of organic amendments in soil.