TITLE:
Heavy Metals, Metalloids, Their Toxic Effect and Living Systems
AUTHORS:
Ferdous Seraj, Tania Rahman
KEYWORDS:
Heavy Metal, Arsenic, Zinc, Nickel, Contaminated Land, Metal Bioavailability, Metal Toxicity, Rhizobia, Rhizosphere
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.9 No.13,
December
17,
2018
ABSTRACT: Pollution of the biosphere by heavy metals is a
global hazard that has accelerated since the beginning of the industrial
revolution. Toxic heavy metals are harmful to living organisms even at low
concentrations whereas heavy metals that are essential trace elements are
required by plants at low concentrations but can become toxic at high
concentrations. Heavy metals released from different sources accumulate in soil
and, where bioavailability is high enough; can adversely affect soil biological
functioning and other properties, leading to the loss of soil and ecosystem
fertility and health. It is important that heavy metal contaminated sites are
remediated as heavy metals do not decompose into less harmful substances like organic
contaminants, and thus are retained in the soil. In this review, we survey and
analysis our current knowledge and understanding of the abundance of heavy
metals in soil, their phytoavailability, their toxicity, their uptake and
transport, role of rhizobia and other microbes and overall rhizosphere
processes.