Sources, Mobility, Reactivity, and Remediation of Heavy Metal(loid) Pollution: A Review

Abstract

Heavy metal(loid)s are a group of elements present commonly in the environment, including Cr, Ni, Cu, Zn, Cd, Hg, Pb, and As elements, among others. While these elements could have their origins in natural sources, anthropogenic activities, such as mining, agriculture, industry, etc., are also responsible for enhancing the concentration of these elements in the ecosystems up to undesirable levels. A few of these metal(loid)s serve as necessary micronutrients for life, while the others are extremely harmful and might affect the entire trophic chain upon entering the natural ecosystems due to their mobility and toxicity characteristics. Most of these heavy metal(loid) pollutants are already recognized for their harmful effects; nevertheless, their environmental control encounters obstruction due to various factors. In this context, the present report details the key points regarding the anthropogenic sources of heavy metal(loid) pollution, which are increasing rapidly with time due to the emerging industry practices and processes, the elements causing this kind of pollution, and the physicochemical processes of these elements occurring in the environment–air interface, soil, and water-air interface. These elements exert a severe impact on the environment, which could be mitigated through the development and application of various remediation techniques. Therefore, the present report concludes with a final discussion on the various remediation treatments currently available for reducing the heavy metal(loid) contamination level in both water and soil.

Impact of Heavy Metal Pollution on the Environment

“…"Most heavy metals occur naturally, but a few are derived from anthropogenic sources. They are characterized with high atomic mass and toxicity to living organisms" [2]. "Toxicity of heavy metals increases by mixing with different environmental elements, such as water, soil, and air.…”