The ability of calcium aluminate cement (CAC) to encapsulate toxic metals (Pb, Zn and Cu) was assessed under two curing conditions. Changes in the consistency and in the setting time were found upon the addition of the nitrates of the target metals. Both Pb and Cu caused a delay in CAC hydration, while Zn accelerated the stiffening of the mortar. Compressive strengths of the metal-doped mortars...

All toxic metals have been known to inhibit different activities of sulphate-reducing bacteria (SRB) at different concentrations. The present study delineates functional responses of two thermophilic SRB species (Desulfotomaculum reducens-HA1 and Desulfotomaculum hydrothermale-HA2) to toxic metals. Bacterial activity was assessed in terms of sulphate reduction and metal precipitation employing ...

the toxicity of four potentially toxic trace elements (cu, ni, pb and zn) to annual atriplex (a.hortensis and a. rosea) was examined to determine if this plant showed sufficient tolerance to be used tophytoremediate soils polluted with these heavy metals. the soils, which contained up to (per kilogram) 501mg cu, 1674 mg ni, 1334 mg pb and 3588 mg of zn were sampled around metal-contaminated sit...

Metals make up the bulk of the periodic table and range from the very light (e.g., beryllium) to the very heavy (e.g., the actinides). Metals are important constituents of life, drive economic activity and industry, but can also be a hazard to human health. The metals can be roughly divided into three groups. The first being those metals, such as iron and zinc, that are essential to human life ...

Environmental toxicants such as toxic metals can alter epigenetic regulatory features such as DNA methylation, histone modification, and non-coding RNA expression. Heavy metals influence gene expression by epigenetic mechanisms and by directly binding to various metal response elements in the target gene promoters. Given the role of epigenetic alterations in regulating genes, there is potential...

The soil and water contaminations are frequently occurred by toxic heavy metals and organic pollutants as a consequence of human activities become a key concern in environmental and health problem. Several toxic metals (Cd, Cu, Hg, Pb, Mn, As, Ni, Zn, etc.) from industrial wastewater and other human activities are directly or indirectly released into the environment. Unlike organic contaminants...

The toxic effects of heavy metals, zinc and copper, in unary and binary solutions were studied using the Microtox acute toxicity test which relies upon the attenuation of light intensity emitted by Vibrio fischeri. The toxic effect Gamma (ratio of the light intensity lost at time t to the light intensity remaining at time t) of zinc could be related to its concentration [X] by a two-parameter e...

Environmental contaminants include the potentially toxic metals lead, cadmium and mercury; the chlorinated pesticides mirex, toxaphene and hexachlorobenzene; chlorinated dioxins and furans; polyaromatic hydrocarbons; and polychlorinated biphenyls. While many of these chemicals are resistant to degradation in the natural environment, they dissolve readily in oils and thus accumulate in the fatty...

Metals occur naturally in the earth's crust, and their contents in the environment can vary between different regions resulting in spatial variations of background concentrations. The distribution of metals in the environment is governed by the properties of the metal and influences of environmental factors (Khlifi & Hamza-Chaffai, 2010). Of the 92 naturally occurring elements, approximately 30...