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Muslim Savin
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HEAVY METAL (Lo Mejor De) 014 Industria Por Tin... [WORK]


Uncontrolled disposal generates serious heavy metals pollution occurring in the water, soil, and plants [7], open burning is cause of CO, CO2, SO, NO, PM10 and other pollutant emissions that affect the atmosphere [8], waste picking within open dump sites pose to serious health risk people working on these areas [9], release of SW in water bodies improve the marine litter globally, enhancing environmental contamination [10]. Therefore, SW mismanagement is cause of sever and various environmental and social impacts, which do not allow improvements in sustainable development.




HEAVY METAL (Lo mejor de) 014 Industria por Tin...


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Together with WEEE mismanagement, used batteries should be also mentioned. For instance, in Iran, almost 10,000 tons of household batteries were imported, most of them have been discarded in MSW without any separation and sent to sanitary landfills [99]. In addition to environmental and human health risks associated with unsafe disposal of used batteries in MSW stream, their landfilling implies the depletion of valuable resources. It is expected that more than 9000 tons of used batteries have been dumped in municipal landfills of Iran in recent decades. The most concern regarding battery disposal in MSW is directed to the high percentage of mercury, cadmium, lithium, nickel, arsenic and other toxic and heavy metals [99].


Most silicon is used industrially without being purified, and indeed, often with comparatively little processing from its natural form. More than 90% of the Earth's crust is composed of silicate minerals, which are compounds of silicon and oxygen, often with metallic ions when negatively charged silicate anions require cations to balance the charge. Many of these have direct commercial uses, such as clays, silica sand, and most kinds of building stone. Thus, the vast majority of uses for silicon are as structural compounds, either as the silicate minerals or silica (crude silicon dioxide). Silicates are used in making Portland cement (made mostly of calcium silicates) which is used in building mortar and modern stucco, but more importantly, combined with silica sand, and gravel (usually containing silicate minerals such as granite), to make the concrete that is the basis of most of the very largest industrial building projects of the modern world.[93]


Inorganic arsenic neurotoxicity may occur from well water contamination, accidental exposure to industrial or agricultural agents, or in the setting of homicidal/suicidal intent. This is to be distinguished from the non-neurotoxic organic arsenic found in some fish and crustaceans, which is often found on urine heavy metal screening. Arsenic neurotoxicity from acute poisoning often occurs 1 to 2 weeks after a severe acute systemic syndrome characterized by nausea, vomiting, and diarrhea. The neuropathy often starts as a length-dependent sensory-predominant painful neuropathy, but in severe forms it may progress to a diffuse sensorimotor polyradiculoneuropathy mimicking Guillain-Barré syndrome (Case 7-2).16 Chronic arsenic exposure can cause an indolent sensory-predominant peripheral neuropathy. Nerve conduction studies in both settings are characterized by slowed conduction velocities. While 24-hour urine sampling will reveal chronic arsenic poisoning, it may not disclose late effects of single or repeated exposures, in which case, it is important to sample hair and nails for arsenic levels.


Examination was notable for moderate-to-severe length-dependent weakness, multimodal sensory loss, and areflexia. Extensive blood work and CSF analysis was normal (at 3 weeks out from her original illness). Nerve conduction studies and EMG showed a severe length-dependent axonal peripheral neuropathy. Twenty-four-hour urine heavy metals showed detectable levels of arsenic, but were within normal limits. Due to clinical suspicion, hair samples were sent for testing for inorganic arsenic levels, which were found to be very elevated.


Heavy metals are well-known environmental pollutants due to their toxicity, persistence in the environment, and bioaccumulative nature. Their natural sources include weathering of metal-bearing rocks and volcanic eruptions, while anthropogenic sources include mining and various industrial and agricultural activities. Mining and industrial processing for extraction of mineral resources and their subsequent applications for industrial, agricultural, and economic development has led to an increase in the mobilization of these elements in the environment and disturbance of their biogeochemical cycles. Contamination of aquatic and terrestrial ecosystems with toxic heavy metals is an environmental problem of public health concern. Being persistent pollutants, heavy metals accumulate in the environment and consequently contaminate the food chains. Accumulation of potentially toxic heavy metals in biota causes a potential health threat to their consumers including humans. This article comprehensively reviews the different aspects of heavy metals as hazardous materials with special focus on their environmental persistence, toxicity for living organisms, and bioaccumulative potential. The bioaccumulation of these elements and its implications for human health are discussed with a special coverage on fish, rice, and tobacco. The article will serve as a valuable educational resource for both undergraduate and graduate students and for researchers in environmental sciences. Environmentally relevant most hazardous heavy metals and metalloids include Cr, Ni, Cu, Zn, Cd, Pb, Hg, and As. The trophic transfer of these elements in aquatic and terrestrial food chains/webs has important implications for wildlife and human health. It is very important to assess and monitor the concentrations of potentially toxic heavy metals and metalloids in different environmental segments and in the resident biota. A comprehensive study of the environmental chemistry and ecotoxicology of hazardous heavy metals and metalloids shows that steps should be taken to minimize the impact of these elements on human health and the environment.


Environmental pollution is one of the major challenges in the modern human society [1]. Environmental contamination and pollution by heavy metals is a threat to the environment and is of serious concern [2, 3]. Rapid industrialization and urbanization have caused contamination of the environment by heavy metals, and their rates of mobilization and transport in the environment have greatly accelerated since 1940s [4, 5]. Their natural sources in the environment include weathering of metal-containing rocks and volcanic eruptions, while principal anthropogenic sources include industrial emissions, mining, smelting, and agricultural activities like application of pesticides and phosphate fertilizers. Combustion of fossil fuels also contributes to the release of heavy metals such as cadmium (Cd) to the environment [6]. Heavy metals are persistent in the environment, contaminate the food chains, and cause different health problems due to their toxicity. Chronic exposure to heavy metals in the environment is a real threat to living organisms [7].


This article comprehensively reviews the different aspects of heavy metals as hazardous materials with a special focus on their environmental persistence, toxicity for living organisms, and bioaccumulative potential. The bioaccumulation of these elements and its implications for human health are discussed with a special coverage on fish, rice, and tobacco. The article will serve as a valuable educational resource for both undergraduate and graduate students and for researchers in environmental sciences.


Sources of heavy metals in the environment can be both natural/geogenic/lithogenic and anthropogenic. The natural or geological sources of heavy metals in the environment include weathering of metal-bearing rocks and volcanic eruptions. The global trends of industrialization and urbanization on Earth have led to an increase in the anthropogenic share of heavy metals in the environment [28]. The anthropogenic sources of heavy metals in the environment include mining and industrial and agricultural activities. These metals (heavy metals) are released during mining and extraction of different elements from their respective ores. Heavy metals released to the atmosphere during mining, smelting, and other industrial processes return to the land through dry and wet deposition. Discharge of wastewaters such as industrial effluents and domestic sewage add heavy metals to the environment. Application of chemical fertilizers and combustion of fossil fuels also contribute to the anthropogenic input of heavy metals in the environment. Regarding contents of heavy metals in commercial chemical fertilizers, phosphate fertilizers are particularly important.


Combustion of fossil fuels in industries, homes, and transportation is an anthropogenic source of heavy metals. Vehicle traffic is among the major anthropogenic sources of heavy metals such as Cr, Zn, Cd, and Pb [32]. Higher concentrations of environmentally important heavy metals have been reported in soils and plants along roads in urban and metropolitan areas. Regarding anthropogenic sources of heavy metals, emissions from coal combustion and other combustion processes are very important [5]. During coal combustion, Cd, Pb, and As are partially volatile, while Hg is fully volatile. In China, combustion of coal is one of the major sources of atmospheric emissions of hazardous trace elements [33]. Table 1 lists some environmentally important data for eight key hazardous trace elements (HTEs), of prime environmental concern, in Chinese coals.


Toxic trace metals pose an important threat to both aquatic and terrestrial ecosystems [39]. After release from both natural and anthropogenic sources, heavy metals contaminate natural water bodies, sediments, and soils. Heavy metals released into the atmosphere in volcanic eruptions and in different industrial emissions also ultimately return to the land and cause contamination of waters and soils. Since heavy metals are persistent in the environment, they either accumulate in biota or leach down into ground waters. Contamination of biota and groundwater with potentially toxic heavy metals has important implications for human health. It is important to assess the degree of heavy metal pollution in riverine ecosystems by investigating the concentrations of these elements and their distribution [40]. Figure 1 shows a conceptual schematic of contamination of an aquatic (riverine) ecosystem with heavy metals. Different physicochemical and climatic factors affect the overall dynamics and biogeochemical cycling of heavy metals in the environment. 041b061a72


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