Cadmium regulations

Liao VH, Freedman JH. 1998. Cadmium-regulated genes from the nematode Caenorhabditis elegans. J Biol Chem... 

In Febmary 1990 the Occupational Safety and Health Administration lU.S.) published a report llrat summarizes the history of cadmium regulation, studies of health problems, and risk calculations for cancer, kidney damage, and other disorders. This report represents a formal step toward implementation of stricter limits on cadmium exposure in the workplace. Some authorities admit that considerably more research is required. 

Rai UN, Gupta M, Tripathi RD, Chandra P. 1998. Cadmium regulated nitrate reductase activity inHydrilla verticillata (1. f.) Royle. Water Soil Air Pollut. 106 171-77... 

Coalition ofJSlortheast Governors. The CONEG model heavy-metal guideline is implemented through state regulations and limits total metal content of lead, chromium, mercury, and cadmium. The limitation of 100 parts per million total is aimed at protecting the environment from the disposal of post-consumer waste. 

Cadmium-based pigments have been hit particularly hard by environmental regulations. As the result, consumption in 1993 was estimated to be between 1.5—5 thousand metric tons. The future of this pigment category is particularly questionable in North America. 

The Occupational Safety and Health Administration (OSHA) regulates the exposure to chemicals ia the workplace. From the poiat of view of the inorganic pigments iadustry, the limits estabUshed for lead and cadmium exposure are particularly important. A comprehensive lead standard adopted by OSHA ia 1978 has been successful ia reduciag the potential for lead contamination ia the workplace. 

Metal compounds, particularly compounds of the heavy metals, have a history of importance as antimicrobial agents. Because of regulations regarding economic poisons in the environment they are no longer widely used in this appHcation. Mercury, lead, cadmium, uranium, and other metals have been imphcated in cases of poisoning that resulted in government response. The metals whose compounds have been of primary interest as antimicrobials are mercury, silver, and copper. 

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. 

Health and Safety Cadmium metal and its compounds are toxic and are injurious to health, and for this reason, cadmium is being replaced by other forms of coating wherever possible. For a number of important applications, however, no suitable alternatives have yet been identified. Where cadmium plating continues to be used, it is essential to comply with the regulations covering the use of cadmium. 

As is the case with assessments of the toxicity of dissolved trace metals, the development of sediment quality criteria (SQC) must be based on the fraction of sediment-associated metal that is bioavailable. Bulk sediments consist of a variety of phases including sediment solids in the silt and clay size fractions, and sediment pore water. Swartz et al. (1985) demonstrated that the bioavailable fraction of cadmium in sediments is correlated with interstitial water cadmium concentrations. More recent work (e.g., Di Toro et al, 1990 Allen et al., 1993 Hansen et al, 1996 Ankley et ai, 1996, and references therein) has demonstrated that the interstitial water concentrations of a suite of trace metals is regulated by an extractable fraction of iron sulfides. 

The detailed mechanism dictating the regulation of the process depends on the specific nature of the system, i.e., on the particular compound to be deposited, complexing agent, solution pH, film thickness, potential, etc. For example, in the case of the Cd-Se system, electroreduction of selenosulfate occurs at more positive potentials for either EDTA-ammonia- or NTA-complexed cadmium [13], whereas for ZnSe, the potential required for the reduction of selenosulfate is already reducing for zinc, implying thus a different mechanism. The metal complex has to be adequately stable and should not interfere with selenosulfate reduction. In these terms. 

The chemical supplier can also identify any regulated pollutants in the facility s treatment chemicals and offer available substitutes. The federally regulated pollutants are cyanide, chrome, copper, nickel, zinc, lead, cadmium, and silver. Local and/or state authorities may regulate other substances, such as tin, ammonia, and phosphate. The current status of cyanide and noncyanide substitute plating processes is shown in Table 9.11... 

Puskarova, A., Ferianc, P, Kormanec, J., Homerova, D., Farewell, A., and Nystrom, T., Regulation of yodA encoding a novel cadmium-induced protein in Escherichia coli, Microbiology, 148 (12), 3801-3811, 2002. 

Hazardous waste burning incinerators, cement kilns, and LWAKs do not follow a tiered approach to regulate the release of toxic metals into the atmosphere. The MACT rule finalized numerical emission standards for three categories of metals mercury, low-volatile metals (arsenic, beryllium, and chromium), and semivolatile metals (lead and cadmium). Units must meet emission standards for the amount of metals emitted. For example, a new cement kiln must meet an emission limit of 120pg/m3 of mercury, 54pg/m3 of low-volatile metals, and 180 pg/m3 of semivolatile metals. 

Shredded circuit boards. Circuit boards are metal boards that hold computer chips, thermostats, batteries, and other electronic components. Circuit boards can be found in computers, televisions, radios, and other electronic equipment. When this equipment is thrown away, these boards can be removed and recycled. Whole circuit boards meet the definition of scrap metal, and are therefore exempt from hazardous waste regulation when recycled. On the other hand, some recycling processes involve shredding the board. Such shredded boards do not meet the exclusion for recycled scrap metal. In order to facilitate the recycling of such materials, U.S. EPA excluded recycled shredded circuit boards from the definition of solid waste, provided that they are stored in containers sufficient to prevent release to the environment, and are free of potentially dangerous components, such as mercury switches, mercury relays, nickel-cadmium batteries, and lithium batteries. 

The rule proposes emission standards for dioxins, furans, mercury, cadmium, lead, PM, hydrochloric acid, chlorine, carbon monoxide, hydrocarbons, and several low-volatile metals. It also proposes a new comparable fuels exclusion and makes significant changes to the existing combustion regulations. 

As was indicated in the previous section, the concentration of iron in the mixed wastewaters ranged from 5980 to 6100 mg/L its pH was 0.7 and zinc concentration was 15 pg/L. Since these wastewaters come only from acid baths and not from other processes of the plant, parameters such as cadmium and fluoride are not encountered. The discharge standards for the metal industry effluents set by the Turkish Water Pollution Control Regulation (Official Gazette, Table 15.7, September 4, 1988) are shown in Table 28.10.1... 

The term regulated battery means a rechargeable battery that (a) contains a cadmium or a lead electrode or any combination of cadmium and lead electrodes or (b) contains other electrode... 

Nickel-cadmium rechargeable batteries are being researched. Alternatives such as cadmium-free nickel and nickel hydride systems are also being researched, but nickel-cadmium batteries are unlikely to be totally replaced. Nickel-cadmium batteries can be reprocessed to reclaim the nickel. However, currently, approximately 80% of all nickel-cadmium batteries are permanently sealed in appliances. Changing regulations may result in easier access to these nickel-cadmium batteries for recycling. 

Cadmium-113 captures neutrons effectively and is suitable in the regulation of nuclear reactors. The isotope is a beta-emitter with a half-life of 10u years (record). 

In mammals, as in yeast, several different metallothionein isoforms are known, each with a particular tissue distribution (Vasak and Hasler, 2000). Their synthesis is regulated at the level of transcription not only by copper (as well as the other divalent metal ions cadmium, mercury and zinc) but also by hormones, notably steroid hormones, that affect cellular differentiation. Intracellular copper accumulates in metallothionein in copper overload diseases, such as Wilson s disease, forming two distinct molecular forms one with 12 Cu(I) equivalents bound, in which all 20 thiolate ligands of the protein participate in metal binding the other with eight Cu(I)/ metallothionein a molecules, with between 12-14 cysteines involved in Cu(I) coordination (Pountney et ah, 1994). Although the role of specific metallothionein isoforms in zinc homeostasis and apoptosis is established, its primary function in copper metabolism remains enigmatic (Vasak and Hasler, 2000). 

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