Through industrial and consumer waste, heavy metals can enter a water supply or even from acidic rain breaking down soils and discharging heavy metals into streams, lakes, waterways, and groundwater. Some overwhelming metals incorporate: • Lead (Pb) • Mercury (Hg) • Chromium (Cr) (in spite of the fact that just the structure Cr(vi) is dangerous) • Zinc (Zn) • Copper (Cu) • Arsenic (As) • Nickel (Ni) • Cadmium (Cd) A few of these components are necessary for human health, and are useful when taken into the form in nourishments or as supplements at suitable, low levels. Alternately, cadmium, lead and mercury have no known living capacity and are lethal to people. Dis... ... middle of paper ... ...(mercurous chloride, Hg2cl2) is utilized as a standard as a part of electrochemical estimations and in medication as a laxative. Mercuric chloride (destructive sublimate, Hgcl2) is utilized as an insect spray, in rodent poison, and as a disinfectant.
It can pose a threat to human health and environment due to its hazardous effect.Heavy metals existence in water can damage many of human part even in low concentration. Therefore removing heavy metals in water are very important.The United States Environmental Protection Agency (USEPA) has set up the maximum contamination levels (MCLs) of heavy metals for surface or groundw... ... middle of paper ... ...ructural polysaccharides,amido, amino, sulphydryl carboxyl groups, alcohols and ester.These functional groups substitute hydrogen ions for metal ionsin solution or donation of an electron pair to form complexes with the metal ions in solutions. Due to abundant binding groups, AWBs could be an enormous potential source of adsorbent materials for decontaminating heavy metals from wastewater (T.A.H. Nguyen a, et al,2013). The hydroxyl and carboxyl groups present in these biopolymers are the responsible of Cr(VI) reduction and subsequent Cr(III) adsorption (Marta López-García a, 2013) (Lin andWang, 2012; Wang and Lee, 2011).
Heavy metals are non-biodegradable and will accumulate in the environment. High concentrations of heavy metals beyond threshold limits pose high risks to the environmental and human health. Apart from mining, other anthropogenic sources of heavy metals include smelting, electroplating, the use of pesticide and fertilizer in agriculture, industrial discharge etc. Should heavy metals enter the food chain through soil contamination they can cause adverse health problems such as lead poisoning, kidney and brain damage. Over the past few decades there have been increasing interests in development of technologies for the remediation of contaminated soils.
Some of the chemicals in the fracking fluid and wastewater have been identified as carcinogens. Many of the other chemicals have been found to be harmful to humans (Environmental). According to Griswold, author of the article “The Fracturing of Pennsylvania,” wastewater is a combination of different chemicals that come from the process of fracking. Not only does this wastewater contain chemicals that were originally used in the drilling, but it also contains harmful substances that come from the earth like salts and other compounds (Griswold). Hundreds of chemicals are used during Marcellus Shale drilling; therefore, the process can cause contamination and pollution.
Metals are inorganic form of contaminants whose extensive use has caused significant environmental pollution that mainly affects soil, watercourses, atmosphere and living systems (Kasassi et al., 2008). Mercury, lead, cadmium and chromium (VI) are considered as toxic metals; whereas, copper, nickel, cobalt and zinc are not as toxic, but their e... ... middle of paper ... ...displaying synthetic phytochelatins. Biotechnol Bioeng.70:518–24. Majare, M. and Bulow, L. (2001): Metal-binding proteins and peptides in bioremediation andphytoremediation of heavy metals. TIBTECH.
Introduction Long-lived radionuclides in radioactive waste are intended to be serious pollutants, they migrate by groundwater and the geologic materials can affect their adsorption. Presence of radionuclides and toxic metals in wastes is a major environmental worries. ( paper khandeh -thorium (IV) The water pollutants by chemical substances, such as arsenic, barium, cadmium, cobalt, cuprum, chromium and rare earth element(REEs) has been a problem during the past few years. Because of rare earth elements (REEs) wide applications in many critical technological areas as well as nuclear fuel cycles (NFC), analytical and separation technologies for these elements are attracting more and more attentions worldwide. [1–3}( 1- 16 dey91].
Introduction Cadmium (Cd) toxicity is one of the most harmful heavy metal contaminations which could severely affect the environment in a number of ways and in turn affect the living population within that environment. This however can be due to a variety of issues such as environmental disruption or human activity. Cadmium is classed as a Class D heavy metal, meaning, “It does not have a known biological function and can be toxic even when in low amounts”. This very toxic water-soluble heavy metal is a by-product during mining, extraction or removing impurities from ores with Copper, Lead and Zinc. One of the well-known disasters in history is Thailand’s cadmium contamination due to zinc mining by humans.
Lead is considered to be a toxic heavy metal. It occurs naturally in the Earth’s crust. However, it tends to combine with other elements to form lead compounds. (Registry, 2011). Moreover, it has no known function in the body and with excess accumulation, either acute or chronic, will cause a wide array of metabolic dysfunctions by interfering with normal metabolic functions (Analytical Research Laboratories, 2012).
Air Emissions Management Plan Activities at construction sites that contribute to daily air pollution include: land clearing, operation of diesel engines, demolition, burning, and working with toxic materials. All construction sites generate high levels of dust (sites that involve demolition of older buildings may also release asbestos), usually from concrete, cement, wood, stone, silica. Dust generated at construction sites is classified as PM10 - particulate matter less than 10 microns in diameter. Due to its lower particle, construction dust can easily spread and be dangerous. Research shows that PM10 can penetrate deeply into the lungs and cause many health problems like respiratory illness, asthma, bronchitis or even cancer.
Most of the heavy metals are toxic or carcinogenic in nature and pose a threat to human health and the environment (Shakibaie et al., 2008; Vinodhini and Narayanan, 2009). Several conventional methods are used for the removal Heavy metals from wastewater includes chemical precipitation, ion exchange and reverse osmosis etc. but major drawbacks with such treatments are produces large amount of sludge and may be ineffective or expensive processes. So, the search for a new, simple, effective and ecofriendly technology involving the removal of toxic heavy metal from wastewater has directed attention towards phytoremediaton( Divya Singh et al., 2012).According to UNEPPhytoremediation can be defined as “the efficient use of plants to remove, detoxify or immobilise environmental contaminants in a growth matrix (soil, water or sediments) through the natural biological, chemical or physical activities and processes of the plants”. The ideal plants for phytoremediation should possess the ability to tolerate and accumulate high levels of heavy metals in their harvestable parts, while producing high biomass.