Dharmendra Kumar Gupta – författare

This book focuses on the mechanistic (microscopic) understanding of radionuclide uptake by plants in contaminated soils and potential use of phytoremediation. The key features concern radionuclide toxicity in plants, how the radioactive materials are absorbed by plants, and how the plants cope with the toxic responses. The respective chapters examine soil classification, natural plant selection, speciation of actinides, kinetic modeling, and case studies on cesium uptake after radiation accidents.

Radionuclide contaminants pose serious problems for biological systems, due to their chemical toxicity and radiological effects. The processes by which radionuclides can be incorporated into vegetation can either originate from activity interception by external plant surfaces (either directly from the atmosphere or from resuspended material), or through uptake of radionuclides via the root system. Subsequent transfer of toxic elements to the human food chain is a concrete danger. Therefore, the molecular mechanisms and genetic basis of transport into and within plants needs to be understood for two reasons: The effectiveness of radionuclide uptake into crop plants – so-called transfer coefficient – is a prerequisite for the calculation of dose due to the food path. On the other hand, efficient radionuclide transfer into plants can be made use of for decontamination of land – so-called phytoremediation, the direct use of living, green plants for in situ removal of pollutants from the environment or to reduce their concentrations to harmless levels.

This book provides an overview to researchers, graduate, and undergraduate students, as well as academicians who are interested in arsenic. It covers human health risks and established cases of human ailments and sheds light on prospective control measures, both biological and physico-chemical.

Arsenic (As) is a widely distributed element in the environment having no known useful physiological function in plants or animals. Historically, this metalloid has been known to be used widely as a poison. Effects of arsenic have come to light in the past few decades due to its increasing contamination in several parts of world, with the worst situation being in Bangladesh and West Bengal, India. The worrying issue is the ingestion of arsenic through water and food and associated health risks due to its carcinogenic and neurotoxic nature. The impact of the problem is widespread, and it has led to extensive research on finding both the causes and solutions. These attempts have allowed us to understand the various probable causes of arsenic contamination in the environment, and at the same time, have provided a number of possible solutions. It is reported that more than 200 mineral species contain As. Generally, As binds with iron and sulfur to form arsenopyrite. According to one estimate from the World Health Organization (WHO), contextual levels of As in soil ranges from 1 to 40 mg kg-1. Arsenic toxicity is related to its oxidation state which is present in the medium. Asis a protoplastic toxin, due to its consequence on sulphydryl group it interferes in cell enzymes, cell respiration and in mitosis. Exposure of As may occur to humans via several industries, such as refining or smelting of metal ores, microelectronics, wood preservation, battery manufacturing, and also to those who work in power plants that burn arsenic-rich coal.

Phytoremediation is an emerging technology that employs higher plants for the clean-up of contaminated environments. Basic and applied research have unequivocally demonstrated that selected plant species possess the genetic potential to accumulate, degrade, metabolize and immobilize a wide range of contaminants.

The main focus of this volume is on the recent advances of technologies using green plants for remediation of various metals and metalloids. Topics include biomonitoring of heavy metal pollution, amendments of higher uptake of toxic metals, transport of heavy metals in plants, and toxicity mechanisms. Further chapters discuss agro-technological methods for minimizing pollution while improving soil quality, transgenic approaches to heavy metal remediation and present protocols for metal remediation via in vitro root cultures.