Farhana Masood

Biosorption of metal ions from aqueous solution and tannery effluent by Bacillus sp. FM1

The metal binding capacity of Bacillus sp. FM1 isolated from soil irrigated with tannery effluent was assessed using synthetic metal solutions and tannery wastewater. Biosorption of Cr(VI) and Cu(II) ions from aqueous solutions using Bacillus was investigated as a function of pH, initial metal ion concentration and contact time. The optimum adsorption pH value observed for Cr(VI) and Cu(II) ions was 2 and 5, respectively. Metal ion uptake increased with increasing initial metal concentration but no significant difference was observed by increasing the time after 60 min. Maximum uptake capacity of chromium was estimated as 64.102 mg g−1, and of copper to 78.125 mg g−1. Equilibrium data were well described by the Langmuir and Freundlich adsorption relations. The presence of functional groups on the cell wall surface of the biomass that may interact with the metal ion was confirmed by Fourier Transform Infrared (FTIR) spectroscopy. The application of Bacillus to remove Cr(VI) and Cu(II) in tannery effluent revealed that the biomass was capable of removing both the metal ions. However, the biosorption performance was slightly lower compared to that of synthetic metal solutions. Several factors may be responsible for this difference. However, the most important factor appears to be the presence of other contaminants such as anions, organics, and other trace metals in the effluent.

Cytotoxic and genotoxic potential of tannery waste contaminated soils.

Soil samples from agricultural fields in the vicinity of industrial area of Jajmau, Kanpur (India) were collected and found to be heavily contaminated with various toxic heavy metals. GC-MS analysis revealed the presence of organic compounds mainly phthalates in contaminated soils. Samples were extracted using dichloromethane (DCM) and hexane solvents, and the extracts were assayed for genotoxic potential using three different bioassays namely Ames Salmonella/mammalian microsome test, DNA repair defective Escherichia coli K-12 mutants and Allium cepa chromosomal aberration assay. TA98 was found to be the most sensitive strain to all the soil extracts tested. The highest mutagenic potential was observed in DCM extracts of soil as compared with hexane extracts for each strain of Salmonella typhimurium. DCM extracts of the soil exhibited maximum damage to the cells at a dose of 40 μl of soil extracts/ml of culture after a 6-h treatment. The survival was 23% in polA, 40% in lexA and 53% in recA mutants when treated with DCM extract of site I. In A. cepa assay, all the test concentrations of soil extracts (5-100%) affected mitotic index in a dose-dependent manner and several types of abnormalities were observed at different mitotic stages with the treatments: C-mitosis, anaphase bridges, laggards, binucleated cells, stickiness, broken and unequal distributions of chromosomes at anaphase stage of cell division. The soil is accumulating a large number of pollutants as a result of wastewater irrigation and this practice of accumulation has an adverse impact on soil health.

Single and Multi-Component Adsorption of Metal Ions by Acinetobacter sp. FM4

This paper reports biosorption of Cr(VI), Cu(II), and Ni(II) onto Acinetobacter sp. FM4 biomass isolated from soil irrigated with tannery effluent from single, binary, and ternary metal solutions. Optimum pH for biosorption was found to be 2.0 for Cr(VI), 5.0 for Cu(II), and 6.0 for Ni(II) ions. Sorption capacities for Cr(VI), Cu(II), and Ni(II) ions were estimated as 90 mg g-1, 93.3 mg g-1, and 66.7 mg g-1, respectively. The combined effect of adsorbing one metal ion in the presence of another metal ion reduced the adsorption capacity of either metal ion. The presence of functional groups on the cell wall surface of the biomass that may interact with the metal ion was confirmed by Fourier Transform Infrared (FTIR) spectroscopy.

Bioremediation of Pesticides from Soil and Wastewater

The rapid increase in demand and development of industrial chemicals, fertilizers, pesticides and pharmaceuticals to sustain and improve quality of life worldwide have resulted in the contamination and high prevalence of these chemicals in air, water and soils, posing a potential threat to the environment. Pesticides are a common hazard around the world, as these chemicals are leaching into soils, groundwater and surface water and creating health concerns in many communities. The persistence of pesticides makes their removal and detoxification a more urgent undertaking. The toxicity or the contamination of pesticides can be reduced by the bioremediation process which involves the use of microbes or plants. Bioremediation technologies have been successfully employed in the field and are gaining more and more importance with increased acceptance of eco-friendly remediation solutions. Owing to complex nature of pesticides, more versatile and robust techniques need to be developed which can produce the desired result in a very cost-effective manner.

Environmental Protection Strategies: An Overview

Environment protection and sustainability are harmonious and sustainability can be achieved by protecting our natural resources. This chapter presents an overview of the different types of problems affecting the environment and recent advances in environmental protection strategies. The role and potential of rhizospheric microorganisms in plant growth in disturbed soils is presented. Agro-industrial wastes and municipal solid wastes management options are discussed; the various sustainable solutions are also highlighted. The health effects of dyes and their different remedial treatment process and also the potential of peroxidases for treatment of dyes are discussed. The resistance and transfer genes in microorganisms and their molecular detection methods are explained along with the ability of environmental bacteria to form biofilms. The biochemical attributes for the assessment of soil ecosystem sustainability and the various methods involved in genotoxicity testing of environmental pollutants are summarized. Pesticides bioremediation strategies from soil and wastewater and the biodegradation of cyanobacteria and their toxins are outlined. The cause of Alfalfa damping off and the characterization of the causal agent are discussed. The significance of biochemical compounds derived from legumes and rhizobacteria (rhizodeposits) with potential in biotechnology are explained. The pulp and paper industry is a big sector and generates large amounts of wastewater; the treatment processes are briefly presented. The contamination of shooting range soils with heavy metals is a matter of concern and the remediation processes are discussed. The chapter ends with the role of biopesticides in sustainable agriculture. Thus, whole work concluded the ill effects of different types of pollution and the waste generated by human activities in the environment. Current trends involved in the remediation and the technologies used for this purpose are presented in detail.

Food Processing: Strategies for Quality Assessment, A Broad Perspective

Food processing is very important in many economies around the world. Food processing may be carried out in the home or by community groups or as cottage industries or more formal commercial formulations with respective sites having increasing levels of sophistication and capital requirements. The aim of the food processing is to ensure microbiological and chemical safety of foods, adequate nutrient content and bioavailability, and acceptability to the consumer and caregiver with regard to sensory properties and ease of preparation. Processing may have either beneficial or harmful effects on these different properties of food, so each of these factors must be taken into account in the design and preparation of complementary foods.

Current Aspects of Metal Resistant Bacteria in Bioremediation: From Genes to Ecosystem

Global industrialization has resulted in a widespread contamination of the environment with persistent addition of organic and inorganic wastes. The contaminants enter the environment either by natural processes or through human activity. The natural contamination originates from excessive withering of minerals from rocks or displacement from the groundwater or subsurface layers of the soil. Disposal of industrial effluents, sewage sludge, deposition of air-borne industrial wastes, military operations, mining, land-fill operations, industrial solid-waste disposal and the growing use of agricultural chemicals such as pesticides, herbicides and fertilizers are sources of human-assisted contamination of the environment. Heavy metals exert some important roles in some biochemical reactions, being essential to the growth and development of microorganisms, plant and animals. However, in high concentrations they can form unspecific compounds, creating cytotoxic effects. They exhibit a range of toxicities towards microorganisms, depending on physico-chemical factors, speciation etc., while toxic effects can arise from natural processes in the soil, and on microbial communities are more commonly associated with anthropogenic contamination or redistribution of toxic metals in terrestrial ecosystems. A variety of mechanisms have been implicated in the adaptation, tolerance, and resistance of microorganisms to a metal pollutant: precipitation of metals as phosphates, carbonates, and/or sulfides, volatilization via methylation or ethylation, physical exclusion of electronegative components in membranes and extracellular polymeric substances (EPS), energy-dependent metal efflux systems, and intracellular sequestration with low molecular weight, cysteine-rich proteins. The efficiency of these mechanisms depends on many parameters, among which the metal itself, the species studied, time, temperature, pH, presence of plant communities near the microfauna, interactions of the metal with other compounds. Most microorganisms are known to have specific genes for resistance to toxic ions of heavy metals. This chapter summarizes the recent progress in the field of molecular microbial ecology of metal resistant bacteria with emphasis that how the genetic capacity of the organisms can be exploited for the remediation of heavy metal pollution. Genetic improvement may help to develop the field of existing methodologies to decontamination processes are also discussed in the chapter.

Methods for Genotoxicity Testing of Environmental Pollutants

Genetic hazard assessment deals with changes in genetic material of organisms, either human or other natural origin. Although considered an important element of the basic mechanisms of evolution, mutations often have a more detrimental effect on individuals and their offspring, and may adversely affect populations. There is consensus about a close association of DNA damage, mutations and the induction of various types of cancer. In eco-genotoxicity, possible effects of mutagenic/genotoxic substances on populations and ecosystems are investigated. Mutagenicity testing has been performed with all types of organisms. For monitoring purposes higher organisms (eukaryotes) are exposed to the environmental compartment “in situ” or in laboratory tests “in vivo”. Mutagenicity represents permanent changes to single genes or chromosomes, while genotoxicity focuses on primary damage of DNA. The bacterial Ames, umuC and SOS chromo assays have been predominantly used. Tests with eukaryotic cells or organisms might be more relevant for human and ecological risk assessment, but generally they are much more time-consuming. Several tests have been developed using the integrity of DNA as a non-specific endpoint of genotoxicity e.g. comet assay, alkaline DNA-elution assay, DNA alkaline unwinding assay, UDS-assay; the comet assay probably the most cost-efficient test among them. Most eukaryotic genotoxicity tests detect macro damage of chromosomes in the visible light microscope following appropriate staining (chromosomal aberration, micronucleus assay, SCE assay). Plants, amphibians, fish and water mussels as well as permanent mammalian cell lines such as V79, CHO or CHL have been used as the test organisms. Newer technologies such as transcriptomics, proteomics and metabolomics provide the opportunity to gain insight into genotoxic mechanisms and also to provide new markers in vitro and in vivo. There is also an increasing number of animal models with relevance to genotoxicity testing. These types of models will undoubtedly have an impact on genotoxicity testing in the future.

Recent Approaches in Risk Assessment of Foods

Food safety is important not only for the people’s general health and daily life, economic development, and social stability but also for the government’s and country’s image. Microbiological and chemical contamination in food is a major cause of illnesses. Food-borne disease remains a real and formidable problem in both developed and developing countries, causing great human suffering and significant economic losses. New science-based approaches to food safety provide an effective way for governments to protect consumers against food-borne disease and plan appropriate response measures when necessary. Risk assessment is a structured science-based process to estimate the likelihood and severity of risk with attendant uncertainty. For risk assessment many organizations recognize four major elements: hazard identification; exposure assessment; dose–response assessment or hazard characterization; and risk characterization. Risk assessment can be descriptive or narrative, qualitative, semi-quantitative, or quantitative. Both qualitative and quantitative risk assessments are important in different circumstances. Food safety risk assessments are undertaken in response to identified chemical or microbial risks to human health. Chemical risk assessments focus on the presence of chemicals such as food additives, food contaminants, or residues of veterinary drugs. A microbial risk assessment evaluates the likelihood of adverse human health effects occurring after exposure to a pathogenic microorganism or to the medium in which the organism occurs. Activities within risk assessment focus on estimating the risk that a hazardous event or factor will negatively affect a population or subpopulation. This chapter deals with the food safety risk assessment process. It introduces a range of techniques that can be used to support risk assessment in practice and outlines the essential characteristics of a good risk assessment.

Environmental Deterioration and Human Health: An Overview

Ever since people have utilised natural resources, environmental quality has started to deteriorate. The increasing incidences of air pollution, water pollution, land and soil pollution, solid and hazardous waste pollution, deforestation, soil erosion, silting and flooding are illustrations of environmental quality deterioration. The deteriorating quality of the environment slowly, but steadily, poses a threat to human security. These threats include increasing exposure to infectious diseases, water scarcity, food scarcity, natural disasters and population displacement. Taken together, they may represent the greatest public health challenge humanity has ever faced. There always seem to be intermediaries connecting the change in the ecosystem and human health. For example, such environmental changes as climate change, land degradation and aquifer depletion seriously affect agricultural production. Agricultural production is a major determinant of nutritional status and population health. Hence, human health is affected by producing or consuming agricultural products and not directly by land degradation or aquifer depletion. However, there are some environmental changes that directly affect the quality of human health, such as a rise in temperature, which causes thermal stresses, respiratory problems and deterioration of aquatic ecosystems leading to waterborne diseases. Other health impacts of the ecosystem degradation may be exacerbated by changes in other systems and processes, such as proliferation of bacteria, distribution of vector organisms or quality and availability of water supplies. The significant changes in health conditions and emergence of new diseases require understanding and are calling for new solutions in implementation of environmental health policies.