Cadmium toxic effects

Solders. Modem dental solders are made from mostly corrosion-resistant, nontoxic metals. Minimal quantities of tin and other elements are often added, some of which could produce toxic effects in the unalloyed state. Each solder is used for specific appHcations (180—188) typical compositions and properties of solders used in dentistry are presented in Table 11. Most of the ingredients of solders are resistant to corrosion, and alloying them with other ingredients renders the alloy safe for use in appHances placed in the oral environment. Silver solders corrode, but are used only for temporary appHances. Available products do not contain cadmium, although cadmium was an ingredient of some silver solders up to ca 1980. 

Sandrin, T. and Maier, R., Effect of pH on cadmium toxicity, speciation, and accumulation during naphthalene biodegradation, Environ Toxicol Chem, 21 (10), 2075-2079, 2002. 

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. 

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). 

Nanoparticles such as those of the heavy metals, like cadmium selenide, cadmium sulfide, lead sulfide, and cadmium telluride are potentially toxic [14,15]. The possible mechanisms by which nanoparticles cause toxicity inside cells are schematically shown in Fig. 2. They need to be coated or capped with low toxicity or nontoxic organic molecules or polymers (e.g., PEG) or with inorganic layers (e.g., ZnS and silica) for most of the biomedical applications. In fact, many biomedical imaging and detection applications of QDs encapsulated by complex molecules do not exhibit noticeable toxic effects [16]. One report shows that the tumor cells labeled with QDs survived in circulation and extravasated into tissues... 

Giesy, J.P., Jr., G.J. Leversee, and D.R. Williams. 1977. Effects of naturally occurring aquatic organic fractions on cadmium toxicity to Simocephalus serrulatus (Daphnidae) and Gambusia affinis (Poeciliidae). Water Res. 11 1013-1020. 

Gomot, A. 1998. Toxic effects of cadmium on reproduction, development, and hatching in the freshwater snail Lymnaea stagnalis for water quality monitoring. Ecotoxicol. Environ. Safety 41 288-297. 

Howell, R. 1985. Effect of zinc on cadmium toxicity to the amphipod Gammarus pulex. Hydrobiologia 123 245-249. 

Arsenic uptake in rabbit intestine is inhibited by phosphate, casein, and various metal-chelating agents (USEPA 1980). Mice and rabbits are significantly protected against sodium arsenite intoxication by (V-(2,3-dimercaptopropyl)phthalamidic acid (Stine et al. 1984). Conversely, the toxic effects of arsenite are potentiated by excess dithiols, cadmium, and lead, as evidenced by reduced food efficiency and disrupted blood chemistry in rodents (Pershagen and Vahter 1979). 

Trace metals (arsenic, cadmium, chromium, copper, nickel, lead, mercury, zinc) Industrial and municipal wastewaters runoff from urban areas and landfill erosion of contaminated soils and sediments atmospheric deposition Toxic effects including birth defects, reproductive failure, cancer, and systemic poisoning. 

Selenium is readily available in a variety of foods including shrimp, meat, dairy products, and grains, with a recommended daily intake of 55 to 70 jug. It occurs in several forms with Se+6 being biologically most important. Selenium is readily absorbed by the intestine and is widely distributed throughout the tissues of the body, with the highest levels in the liver and kidney. It is active in a variety of cellular functions and interacts with vitamin E. Selenium appears to reduce the toxic effects of metals such as cadmium and mercury and to have anticarcinogenic activity. Selenium produces notable adverse effects both in deficiency and excess thus recommended daily intake for adults is approximately 70 Jg/day but should not exceed 200 pg/day. 

Thus, cadmium causes multi-organ toxicity, and at least some of the toxic effects are due to it being a divalent metal similar to zinc and able to bind to sulfydryl groups. 

Production. Since soluble cadmium compounds have a toxic effect on human beings and the environment, all wastewater originating from the production of cadmium pigments must be treated to remove cadmium. In the EU, the following... 

Cadmium pigments have no acute toxic effect (oral LD50, rat, > 10 g/kg). The pigments do not have any adverse effects on the skin and mucous membranes. 

Acute poisoning may result from inhalation of cadmium dusts and fumes (usually cadmium oxide) and from the ingestion of cadmium salts. The major toxic effects are due to local irritation. In the case of oral intake, these include nausea, vomiting, salivation, diarrhoea and abdominal cramp. Cadmium is more toxic when inhaled. Signs and symptoms, which appear after a few hours, include irritation of the upper respiratory tract, chest pains, nausea, dizziness and diarrhoea. Permanent lung damage may occur in the form of emphysema and peribronchial and perivascular fibrosis. Death is usually due to massive pulmonary oedema. 

The toxic effects of chronic exposure to cadmium differ somewhat with the route of exposure. The kidney is affected following either pulmonary or gastrointestinal exposure marked effects are observed in the lungs only after exposure by inhalation. 

Due to the possible toxic effects of Hg, alternative electrodes have been sought, such as bismuth, which has recently been used by Kadara and Tothill [155,156] for the determination of Pb2+ and Cd2+ at an SPCE. In this investigation, stripping chronopotentiometric measurements were carried out by depositing a metallic film of bismuth in situ with the target metal ions (lead and cadmium). A deposition potential was applied to preconcentrate the analytes, after which, a constant current was applied to strip the preconcentrated analytes until a limit of —0.2 V. The concentrations for Pb2+ and Cd2+ in the wastewater samples and acetic acid extracts of soils were quantified by the use of a multiple standard addition method. 

Koukal, B., Gueguen, C., Pardos, M. and Dominik, J. (2003) Influence of humic substances on the toxic effects of cadmium and zinc to the green alga Pseudokirchneriella subcapitata, Chemosphere 53 (8), 953-961. 

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