Cadmium human health

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). 

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. 

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. 

Proposed cadmium criteria for the protection of living resources and human health... 

Table 1.8 Proposed Cadmium Criteria for the Protection of Living Resources and Human Health Resource, Criterion, and Other Variables Effective Concentration Ref.a... 

Recommendations for cadmium in air and human health protection under the worst scenario (Table 1.8) assume that total daily air intake is 27.14 m3 for an adult human who spends about 6.3 h in occupational exposure to air containing 100 pg Cd/m3 (USEPA 1980). Under these conditions, a 70-kg adult would retain about 361 pg Cd/day, based on an absorption factor of 0.5 (USEPA 1980), and most of this cadmium would probably be translocated to the kidney a critical threshold level of 200 mg Cd/kg in the kidney would be reached in about 1.52 years. It is not now known... 

Heavy metals in the environment, especially their accumulation in soils, is a serious environmental problem which the whole world faces (Du et al. 2005). The farmland soils are an important media of the ecological cycle of Cadmium, and its harm to human health can t be neglected (Wu et al. 2004). Heavy metal migration, transformation and toxicity to plants in soil are directly influenced by the quantity proportions of various forms (Zhu et al. 2002). The toxicity of water-extractable and adsorbed and exchangeable metals are the greatest, and residual metals is the lowest (Liu etal. 2002). Different forms have different bioavailability thus their influences on the environment and human health are different. It is critical to have a good understanding of Cadmium forms in soil. This paper describes the Cadmium forms in the acid soils of eastern China. 

An EC study has found that cadmium pigments present no significant threat to human health or the environment, says the International Cadmium Association. In view of the positive life cycle assessment, EC Member States voted earlier this year that there should be no further restrictions on the marketing and use of cadmium pigments in plastics. INTERNATIONAL CADMIUM ASSOCIATION... 

The most severe form of chronic cadmium (Cd) poisoning caused by prolonged oral Cd ingestion is Itai-itai disease, which developed in numerous inhabitants of the Jinzu River basin in Toyama Prefecture, Japan in the 1950s (Figure 20.7). For the first time, cadmium pollution was shown to have severe consequences on human health, particularly in women. The most important effects were softening of the bones and kidney failure. The name of the disease is derived from the painful screams (Japanese /to/) caused by the severe pain in the... 

At Kirtland Air Force Base in New Mexico, an in situ application of MAECTITE was used to treat 2000 yd of soil contaminated with lead and cadmium. Following MAECTITE treatment, leachable lead and cadmium levels in soils were less than residential human health standards. In addition, contaminant levels were low enough that the treated waste could be categorized as nonhazardous by Resource Conservation and Recovery Act (RCRA) standards. Total costs for the project were 125,000, which was almost 40% less than alternative stabilization techniques considered at the site (D21483F, p. 3). 

Sweden s restrictions on cadmium provide another example of justifiable precaution. Elevated cadmium levels in crops become a human health risk because ingested cadmium causes a progressive accumulation of the metal in the kidney cortex, eventually causing tissue damage. The success of the Swedish restrictions was measured as reversals in the progressive build-up of the metal in the environment.16... 

MORGAN H (ed), The Shipham Report An investigation into cadmium contamination and its implications for human health , The Science of the Total Environment 1988 75 (1). 

Technetium and other transition metals can be lifesavers, but other metals in this part of the periodic table can threaten human health. Mercury, cadmium, and nickel are some of the transition metals that can cause problems ranging from skin allergies to toxic poisoning. Some people have also been concerned about the health risks of a mercury-containing compound in vaccines, the injections given to prevent diseases such as the flu. However, there is no evidence that this compound is unsafe, according to most medical experts. 

Okrent and Xing (1993) analyzed the cancer risk resulting from inadvertent intrusion into a RCRA facility for hazardous chemical waste. The facility was assumed to contain waste from production of veterinary pharmaceuticals and other wastes that resulted in concentrations of 1,000 mg kg-1 of arsenic and 100 mg kg 1 of beryllium, cadmium, chromium, and nickel. A scenario for inadvertent intrusion involving permanent site occupancy similar to the scenario used by NRC to develop the Class-A, -B, and -C limits for near-surface disposal of radioactive waste (NRC, 1982b) was used to estimate the human health consequences of the postulated intrusion. 

Field and laboratory studies were conducted to determine the levels of Cd, Pb, and HCBD in various samples collected from a swamp environment in Louisiana and to assess the toxicities of As, Cd, and Hg to two species of aquatic organisms (bluegills and crawfish) indigenous to this swamp [18]. Cadmium and Pb were present in almost all collected samples. Their concentrations in fish were below the action levels set by EPA for the protection of human health. However, hazardous levels of these two elements were found in samples of crawfish, vegetation, soil, sediment, and water to some extent. Low levels of HCBD were recorded in water and sediment samples. In bioassay studies, Hg was found to be the most toxic metal, while As was the least toxic. Between the two test organisms, blue-gills appeared to be more sensitive than crawfish. Mixtures of Cd with As or Hg resulted in a combined toxic effect which was simply additive. However, a synergistic effect was recorded with the mixtures of As and Hg. 

Bernard A, Roels H, Buchet JP, Cardenas A, Lauwerys R. Cadmium and health the Belgian experience. In Cadmium in the human environment toxicity and carcinogenicity. Nordberg G, Herber R, Alessio L (editors). International Agency for Research on Cancer (lARC) Scientific Publications, Vol 118, Lyon 1992 p. 15-33. 

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