Cadmium human

Silver-brazed joints are used when temperature or the combination of temperature and pressure is beyond the range of soldered joints. They are also more reliable in the event of plant fires and are more resistant to vibration. If they are used for fluids that are flammable, toxic, or damaging to human tissue, appropriate safeguarding is required by the code. There are OSHA regulations governing the use of silver brazing alloys containing cadmium and other toxic materials. 

Air-poUutant effects on neural and sensory functions in humans vary widely. Odorous pollutants cause only minor annoyance yet, if persistent, they can lead to irritation, emotional upset, anorexia, and mental depression. Carbon monoxide can cause death secondary to the depression of the respiratory centers of the central nervous system. Short of death, repeated and prolonged exposure to carbon monoxide can alter sensory protection, temporal perception, and higher mental functions. Lipid-soluble aerosols can enter the body and be absorbed in the lipids of the central nervous system. Once there, their effects may persist long after the initial contact has been removed. Examples of agents of long-term chronic effects are organic phosphate pesticides and aerosols carrying the metals lead, mercury, and cadmium. 

Cadmium is extremely toxic and accumulates in humans mainly in the kidneys and liver prolonged intake, even of very small amounts, leads to dysfunction of the kidneys. It acts by binding to the —SH group of cysteine residues in proteins and so inhibits SH enzymes. It can also inhibit the action of zinc enzymes by displacing the zinc. 

Zinc and cadmium have an oxidation number of +2 in all their compounds. Zinc is an essential element for human health. It is present in many enzymes and plays a role in the expression of DNA and in growth. Zinc is toxic only in very-high amounts. However, cadmium is a deadly poison that disrupts metabolism by-substituting for other essential metals in the body such as zinc and calcium, leading to soft bones and to kidney and lung disorders. 

A number of environmental issues have received widespread publicity (Table 7.1), from major accidents at plants (e.g., Seveso and Bhopal) to the global and regional impacts associated with energy utilization (e.g., carbon dioxide, acid rain, and photochemical oxidants), the improper disposal of chemical waste (e.g., Love Canal and Times Beach), and chemicals that have dispersed and bioaccumulated affecting wildlife (e.g., PCBs and DDT) and human health (e.g., cadmium, mercury, and asbestos). 

Cadmium is an extremely toxic metal that finds its way into the aqueous environment as a result of some human activities. A major cause of cadmium pollution is zinc mining and processing, because natural deposits of ZnS ores usually also contain CdS. During the processing of these ores, highly insoluble cadmium sulfide ( sp = 7.9 X 10 ) maybe converted into considerably less insoluble cadmium hydroxide (.E p — 7.2 X 10" ). What mass of Cd (OH)2 will dissolve in l.OOx lO L of an aqueous solution ... 

Evenson, M. A. and Anderson, C. T., Jr. Ultramlcro Analysis for Copper, Cadmium and Zinc In Human Liver Tissue by Use of Atomic Absorption Spectrophotometry and the Heated Graphite Tube Atomizer". Clin. Chem. (1975), 2, 537-543. 

Standards imposed to the industrial waste streams charged in heavy metals are more and more drastic in accordance with the updated knowledges of the toxicity of mercury, cadmium, lead, chromium... when they enter the human food chain after accumulating in plants and animals (Forster Wittmann, 1983). Nowadays, the use of biosorbents (Volesky, 1990) is more and more considered to complete conventional (physical and chemical) methods of removal that have shown their limits and/or are prohibitively expensive for metal concentrations typically below 100 mg.l-i. 

The determination of lead in blood is the most widespread clinical use of ASV The technique is attractive because it is rapid, simple and reproducible A recent advance is to couple ASV to flow injection analysis in order to automate the process so that smaller samples and shorter analysis time can be achieved Lead is also routinely determined in bonemeal meant for human consumption by ASV Both lead and cadmium are determined in agricultural crops by ASV... 

Vahter M (1982) Assessment of human exposure to lead and cadmium through biological monitoring. Natl Swed Inst Environ Med, Stockholm. 

Because many batteries contain toxic constituents such as mercury and cadmium, they pose a potential threat to human health and the environment when improperly disposed. Although batteries generally make up only a tiny portion of MSW, <1%, they account for a disproportionate amount of the toxic heavy metals in MSW. For example, the U.S. EPA has reported that, as of 1995, nickel-cadmium batteries accounted for 75% of the cadmium found in MSW. When MSW is incinerated or disposed of in landfills, under certain improper management scenarios, these toxics can be released into the environment. 

Cadmium (Cd) anode cells are at present manufactured based on nickel-cadmium, silver-cadmium, and mercury-cadmium couples. Thus wastewater streams from cadmium-based battery industries carry toxic metals cadmium, nickel, silver, and mercury, of which Cd is regarded the most hazardous. It is estimated that globally, manufacturing activities add about 3-10 times more Cd to the atmosphere than from natural resources such as forest fire and volcanic emissions. As a matter of fact, some studies have shown that NiCd batteries contribute almost 80% of cadmium to the environment,4,23 while the atmosphere is contaminated when cadmium is smelted and released as vapor into the atmosphere4 Consequently, terrestrial, aquatic, and atmospheric environments become contaminated with cadmium and remain reservoirs for human cadmium poisoning. 

Accumulation of cadmium in agricultural soils leads to increased cadmium uptake by crops and vegetables, grown for human consumption.17... 

The information available regarding the association of occupational exposure to lead with increased cancer risk is generally limited in its usefulness because the actual compound(s) of lead, the route(s) of exposure, and level(s) of lead to which the workers were exposed were often not reported. Furthermore, potential for exposure to other chemicals including arsenic, cadmium, and antimony occurred, particularly in lead smelters, and smoking was a possible confounder (Cooper 1976 IARC 1987). These studies, therefore, are not sufficient to determine the carcinogenicity of lead in humans, and the following discussion is restricted to the most comprehensive of these studies. 

An in vitro study demonstrated that cadmium and zinc have an antagonistic effect on the inhibitory effects of lead on human ALAD activity (Davis and Avram 1978). Cadmium was 40-100 times more potent than zinc in activating ALAD. Furthermore, the combined effects of cadmium and lead in tissue resulted in an additively increased risk of mortality related to cardiac failure in humans with significant relation to age in 80% of the cases (Voors et al. 1982). 

ATSDR. 1995. Multisite lead and cadmium exposure study with biological markers incorporated. Atlanta, GA U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry. 

Dabeka RW, Karpinski KF, McKenzie AD, et al. 1988. Survey of lead and cadmium in human milk and correlation of levels with environmental and food factors. Sci Total Environ 71 65-66. 

Davis JR, Avram MJ. 1978. A comparison of the stimulatory effects of cadmium and zinc on normal and lead-inhibited human erythrocytic delta-aminolevulinic acid dehydratase activity in vitro. Toxicol Appl Pharmacol 44 181 -190. 

Gasiorek K, Bauchinger M. 1981. Chromosome changes in human lymphocytes after separate and combined treatment with divalent salts of lead, cadmium, and zinc. Environ Mut 3 513-518. 

Oberdorster G. 1992. Pulmonary deposition, clearance and effects of inhaled soluble and insoluble cadmium compounds. In Nordberg GF, Herber RFM, Alessio L, eds. Cadmium in the human environment Toxicity and carcinogenicity. Lyon International Agency for Research on Cancer,... 

The evaluation of risk has underlined the possible adverse effects both on human health after the exposure to drinking water contaminated by landfill leachate and on small rodents and aquatic species at the hypothesized condition for humans, the estimated toxic effects of the raw leachate are mainly due to the levels of ammonia and cadmium and carcinogenic effects are induced by arsenic first and then by PCBs and PCDD/Fs while ecological potential risk is mainly attributable to the concentration of inorganic compounds, in particular ammonia for small rodents, cadmium, ammonia, and heavy metals for fishes. 

Eight trace elements of greatest environmental concern are chosen, which are arsenic (As), mercury (Hg), lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu) and zinc (Zn). These eight trace elements will be discussed in this chapter in the order of their production and level of environmental concern, as presented above. Of these, copper and lead are known to be the earliest metals utilized by humans. Lead was used by humankind at least 5000 years ago (Settle and Patterson, 1980 Adriano, 1986). The production of these eight elements has increased considerably since the dawn of the industrial age in the 1850s (Table 9.1). 

PDT candidate. Indeed, it is effective against human leukemia cells,128 284 and as a photobactericide.128 285 286 However, concerns about solubility and cadmium toxicity led to a discontinuation of biological work,128 and in any case the cadmium(II) complex was soon overtaken as a PDT sensitizer by the lutetium(III) derivative (32) (Section 9.22.7.1). 

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