Abstract
Environmental pollution is one of the most acute global problems. Pollution is present at the every corners of the globe. Several methods are used for monitoring the pollutants in the environment. The present chapter includes the wide variety of testing such as physical, chemical, biological and as well molecular to determine the level of biodegradable contaminated substances in the environment and also check the feasibility of different bioremediation techniques. The monitoring and testing are essential and have an enormous impact on the cost of full-scale remediation. Successful remediation techniques completely degrade the contaminants. A successful bioremediation approach requires sufficient evidences for the non-toxicity of the contaminant. Current monitoring techniques require the disappearance of the contaminants. Different recombinant techniques also play great role to assess the pollution level. In the field and focus on interdisciplinary research, bioremediation technology will go a long way in cleaning our polluted environment in near future. Research on improved microbial strains and bioanalytical methods for measuring the level of contaminants should be strengthen.
TopIntroduction
Intensification of agriculture and manufacturing industries has resulted in increased release of a wide range of xenobiotic compounds to the environment. Excess loading of hazardous waste has led to scarcity of clean water and disturbances of soil thus limiting crop production.
Microorganisms have an extensive but finite capacity to recycle synthetic organic molecules. One difficulty with microbial bioremediation is that not all components of chemical mixtures are degraded with equal efficiency. By genetic engineering, the substrate range can be widened to include xenobiotics that are normally recalcitrant to degradation. Regulation of the deliberate release of genetically modified microorganisms requires, however, knowledge on the survival and effects of the inoculum in the environment (Gustafsson & Jansson, 1993). Government and the public become aware of the importance of the environment. To understand the changes in the environment, caused either by natural or mankind, large numbers of environmental parameters are considered. The range of environmental changes may from slow increase in global temperature to rapid accumulation of heavy metals and xenobiotics. Some changes are so slow that their determination requires careful monitoring for long time periods (Atlas, & Bartha, 1993). Pollution is defined by Holdgate in 1979 as “the introduction into the environment of substances or energy which causes hazards to human health, harm to living resources and ecological damage”. The first major human influence on the environment was perhaps agriculture but the industrial revolution was also very significant. The main environment pollutant are inorganic compounds such as metals and nitrates, organic compounds, microorganisms including pathogens, gaseous compounds such as volatile, gases and particulates which can contaminate land, air and water (Table 1).
Table 1. Industry and their contaminants
| Industry | Contaminants |
| Chemicals | Acid, alkali, metals, solvents, phenols, organic compounds, chlorophenols |
| Petrochemicals | Hydrocarbon, Phenols, Acids, alkali |
| Metals | Metals especially Fe, Cu, Ni, Cr, Zn, Cd |
| Energy | Phenols, Cyanide, Sulphur, Compounds, coal and coke dusts |
| Mineral Extraction | Metals Cu, Zn and Pb, gas leachate |
| Water supply and sewage | Microorganisms and methane |
Reeve, 1994.
The environmental conditions and the properties of the pollutant affect the fate of pollutant in the environment. The properties of the compounds such as solubility, volatility and reactivity affect the environment. The contaminants are not restricted to their site of introduction but depending on conditions which can migrate and contaminate other parts of the environment such as lakes, rivers and sea. Always the pollutants are not single but can be complex mixtures of toxic compounds. National laws are normally associated with a number of acts covering many types of pollutants, industries and conditions (Figure 1).
Key Terms in this Chapter
Metallothioneins (MTs): It is a low molecular weight (6-7 kDa), cystine-rich proteins encoded by the Smt locus and essentially play key roles in metal detoxification process in many microorganisms first discovered in Synechococcus PCC 7942.
Enzyme-linked immunosorbent assay (ELISA): It is a test that uses antibodies and colour change to identify a substance. After the antigen is immobilized, the detection antibody is added, forming a complex with the antigen.
Ames Test: A microbiological assay that is used to assess the mutagenic potential of chemical compounds.
Xenobiotic: Xenobiotics are manmade foreign organic compounds that are found as pollutants in the natural environment.
Microbial Metal-Sequestration: Microbe sequesters metals by various mechanisms such as, binding, crystallization, precipitation, metal and mineral nanoparticle deposition, complexion, chemical transformation, volatilization, etc., to tackle metal toxicity.
Bio-Monitoring: Monitoring activities in human beings, using biomarkers, that focus on environmental exposures, diseases and/or disorders and genetic susceptibility, and their potential relationships.
Denaturing Gradient Gel Electrophoresis (DGGE): It is a kind of electrophoresis method for molecular fingerprinting that separates polymerase chain reaction (PCR)-generated DNA products on the basis of sequence differences that results in differential denaturing characteristics of the DNA.
Fluorescence in Situ Hybridisation (FISH): is a cytogenetic technique that uses fluorescent probes that bind to only those parts of the chromosome with a high degree of sequence complementarity.
Bio-Marker: Substances (molecules) used as indicators of a biologic state – i.e. as an indicator of normal or pathogenic processes or of biological response to an external agent.
Matrix-Assisted Laser Desorption Ionization (MALDI): It is a soft ionizing technique used in mass spectrometry, allowing the analysis of biomolecules (DNA, proteins, peptide) and large organic molecules (polymers and dendrimers) which tend to be fragile and fragment when ionized by more conventional ionizing methods.