current eco-friendly and sustainable methods for heavy metals remediation of contaminated soil and water: special emphasis on use of genetic engineering and nanotechnology

Anthropogenic activities have polluted soil and aquatic ecosystems by introducing harmful heavy metals (hms) such as cadmium, copper, mercury, lead, manganese, nickel, zinc, and others. these hms lead to serious health conditions in humans like cancer, skin lesions, birth defects, liver and kidney damage, and mental retardation leading to other disabilities. conventional methods of hm remediation of contaminated soil and water include physical, chemical, biological, and integrated methods. the use of physical and chemical methods, in isolation, has been reduced in practice, owing to their negative impacts, however, work on suitable integrated approaches, and the use of organisms for hm remediation has been in steady progress since past few decades. these approaches have proved to be eco-friendly, cost-effective, and show reduced negative impacts on the environment and biota. however, there is consistent increase in anthropogenic contribution to this problem, so, to keep pace with it, more recently work is in advancement on exploiting the biological system to increase the efficiency of bioremediation, using the latest technologies such as genetic engineering and nanotechnology. this paper provides an overview of the current methods deployed to address this problem, developments made in this field in past few decades, and evokes a research thrust that might lead to novel remediation approaches in the future.