Heavy metals are normally occurring elements that have a density at least 5 times higher than of water. Their plentiful domestic, industrial, agricultural and technological usages have led to their widespread distribution in the environment; raising worries over their possible impacts on human health and the environment. The toxicity of heavy metals relies on numerous factors including the dose...

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 this research the operation of fixed activated sludge system for treatment of wastewater containing heavy metal compounds, by use of fas pilot ,a plaxy glass tank with three section; these section are downward-flow aerated reactor, upward-flow aerated reactor and gravity sediment unit, length and width and height of each part was respectively 15.7cm, 31.5cm , 51.5 cm and feeding with the syn...

With the development of industrialization and urbanization, heavy metals contamination has become a major environmental problem. Numerous investigations have revealed an association between heavy metal exposure and the incidence and mortality of gastric cancer. The mechanisms of heavy metals (lead, cadmium, mercury, chromium, and arsenic) contamination leading to gastric cancer are concluded in...

background: this study was conducted to estimate the level of heavy metals accumulate in vegetables irrigated with contaminated water compared with those irrigated with fresh water in hamadan, west of iran in 2012. methods: sixty samples of different vegetables i.e., parsley, tarragon, sweat basil and leek irrigated with contaminated water and thirty six samples from three different adjacent ar...

The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD/SO4(2-) ratio. T...

heavy metals are highly poisonous in the environment, even in small quantities, and endanger certain species and all live beings. current methods of removing heavy metals from aqueous media include chemical sequestration, ion exchange, surface absorption, membrane processes, oxidation and revival procedures which have high investment and exploitation costs. hence, it is significantly necessary ...

Lead, cadmium, mercury and arsenic are the most important heavy metals which may cause health risks following consumption of contaminated foods. Table salt is one the mostly used food additive with unique place in food consumption. Although purified table salt is expected to have lower level of contamination, some Iranians still prefer to use rock salt. Use of rock salt for food purposes has be...