Metals from mining and metallurgical industries and their toxicological impacts on plants

Abstract

The growth of population, increasing urbanization and rising standards of human have contributed to increase in both quantity and variety of solid wastes generated by agricultural, domestic and industrial activities. Industrial wastes contributed more than 85 % of solid waste generation globally. Metals are the major component of almost all the industrial activities but their mining, extraction, purification and various manufacturing processes generate mining and metallurgical wastes having enormous environmental and health impacts. This chapter aims to describe the metals in solid wastes from mining and metallurgical industries and their toxicological impacts on plant community. Industrial wastes are composed of a wide range of essential macro- and micronutrients such as Na, K, Ca, Mg, Mn, Fe, Cu, Zn, Ni, Co, and Mo which are required by plants for their growth and development. But the concentrations of micronutrients in plants when they exceed certain thresholds may interfere with plant metabolic activities leading to the reduction in their productivity. Similarly, non-essential metals and metalloids such as Cd, Pb, As, Al, Bi, Cr, Hg, Ti and Si at elevated concentrations in plants cause phytotoxic effects and lead to food chain contamination. These wastes are generated in huge quantities and discarded without any proper pretreatment; therefore, chances of contamination of environmental components are obvious. This chapter also suggests the possible and better management opportunities including site restoration by rehabilitation and phytoremediation of metal-contaminated sites using native and medicinal plant species to reduce food chain contamination and an ultimate risk to human health.