Heavy metals are metallic elements which have a high atomic weight and a density much greater (at least 5 times) than water. There are more than 20 heavy metals, but four are of particular concern to human health: lead (Pb), cadmium (Cd), mercury (Hg) and inorganic arsenic (As). According to the US Agency for Toxic Substances and Disease Registry, these four heavy metals are four of the top six...

Heavy metals are introduced into aquatic ecosystems from industrial wastes, agricultural runoff and mining activities. The toxicity of heavy metal ions in solution to microalgae is well known. The essentiality and toxicity of heavy metals has been a subject of extensive research (Stokes 1983). From a biological point of view, heavy metals can be divided into two categories: essential and non-es...

In the following discussion of the toxicology of the ' newer' metals, it is perhaps more accurate to refer to them as metals which have only recently become of industrial importance. Most of the metals mentioned have long been known, and in some instances have actually been used in quantity. However, many new types of use have developed, or unusual compounds have become important industrially a...

background and purpose: determination of heavy metals in oils is necessary to establish quality standards on a country level. this study aimed to determine of heavy metal contents (cr, ni, as, cd, hg, pb, sb, sn, sr, al) in 12 seed oil samples in iran by inductively coupled plasma-optical emission spectrometry (icp-oes). materials and methods: the concentrations of heavy metal were determined b...

Bioremediation strategies that depend on bacterial sulfate reduction for heavy metals remediation harness the reactivity of these metals with biogenic aqueous sulfide. Quantitative knowledge of the degree to which specific toxic metals are partitioned into various sulfide, oxide, or other phases is important for predicting the long-term mobility of these metals under environmental conditions. H...

The discharge of potentially toxic trace metals into the environment has become a global problem. As a result of industrial activities and technological development, the amount of heavy metal ions discharged into streams and rivers by industrial and municipal waste-water have been increasing. In addition to natural sources of heavy metals (i.e. geologic weathering, volcanic activity, and animal...

Heavy metal pollution represents an important environmental problem due to the toxic effects of metals. Their accumulation throughout the food chain leads to serious ecological and health problems. The remediation of environments metal contaminated through physico-chemical methods present major disadvantages such as high energy consumption, high costs and incomplete removal of metal ions. Bioso...

in this study, concentrations of heavy metals in soils around a zn-smelter in qeshm island, iran, are investigated. calculated geoaccumulation index (igeo), contamination factor (cf), and contamination degree (cdeg) values indicate surface soil contamination by toxic metals (as, cd, pb, and zn). the results also indicate that most contaminated areas are located in the vicinity of the smelter an...

This paper focuses on the general ways in which microbes interact with metals. Some bacteria have evolved mechanisms to detoxify heavy metals, and some even use them for respiration. Microbial interactions with metals may have several implications for the environment. Microbes may play a large role in the biogeochemical cycling of toxic heavy metals also in cleaning up or remediating metal-cont...