Water pollution is an issue of great concern worldwide, and it can be broadly divided into three main categories, that is, contamination by organic compounds, inorganic compounds (e.g., heavy metals), and microorganisms. In recent years, the number of research studies concerning the use of efficient processes to clean up and minimize the pollution of water bodies has been increasing. In this context, the use of bioremediation processes for the removal of toxic metals from aqueous solutions is gaining considerable attention. Bioremediation can be defined as the ability of certain biomolecules or types of biomass to bind and concentrate selected ions or other molecules present in aqueous solutions. Bioremediation using microorganisms shows great potential for future development due to its environmental compatibility and possible cost-effectiveness. A wide range of microorganisms, including bacteria, fungi, yeasts, and algae, can act as biologically active methylators, which are able to at least modify toxic species. Many microbial detoxification processes involve the efflux or exclusion of metal ions from the cell, which in some cases can result in high local concentrations of metals at the cell surface, where they can react with biogenic ligands and precipitate. Although microorganisms cannot destroy metals, they can alter their chemical properties via a surprising array of mechanisms. The main purpose of this chapter is to provide an update on the recent literature concerning the strategies available for the remediation of metal-contaminated water bodies using microorganisms and to critically discuss their main advantages and weaknesses. The focus is on the heavy metals associated with environmental contamination, for instance, lead (Pb), cadmium (Cd), and chromium (Cr), which are potentially hazardous to ecosystems. The types of microorganisms that are used in bioremediation processes due to their natural capacity to biosorb toxic heavy metal ions are discussed in detail. This chapter summarizes existing knowledge on various aspects of the fundamentals and applications of bioremediation and critically reviews the obstacles to its commercial success and future perspectives.
Part of the book: Advances in Bioremediation of Wastewater and Polluted Soil
Humans require several trace elements as components of the diet. Some of these elements are required in extremely small quantities (only micrograms per day). On the other hand, in higher concentrations, some elements may also have deleterious, even lethal, effects. Metals such as arsenic, chromium (Cr), lead (Pb), and mercury (Hg) are naturally occurring chemical compounds. The contamination of food with these metals occurs mainly through human activities, such as farming and industry, or from contamination during food processing and storage. People can be exposed to these metals by ingesting contaminated food or water, and their accumulation in the body can lead to harmful effects over time. The main objective of this chapter is to provide a literature review on the various types of foodborne poisoning caused by the contamination of food with arsenic, Cr, Pb, and Hg and on food safety issues associated with the presence of these metals in food. Research findings from various studies carried out to examine the relationship between metal exposure and the adverse health effects of metals are addressed.
Part of the book: Significance, Prevention and Control of Food Related Diseases
The discovery of new drugs, especially when many samples have to be analyzed in the minimum of time, demand the improvement or development of new analytical methods. Various techniques may be employed for this purpose. In this context, this chapter gathers the collection of paper and represents the review of past work on spectrophotometric technique coupled to a continuous flow system to determine low concentrations of several chemical species in different kinds of pharmaceutical and biological samples. A short historical background of the flow-injection analysis technique and a brief discussion of the basic principles and potential are presented. Part of this chapter is devoted to describing the sample preparation techniques, principles, and figures of merit of analytical methods. Representative applications of flow-injection spectrophotometry to pharmaceutical and biomedical analysis are also described.
Part of the book: Spectroscopic Analyses