Human body arsenic toxicity

Many organ systems in the human body can be affected by chronic exposure to arsenic (Agency for Toxic Substances and Disease Registry (ATSDR), 2007 World Health Organization (WHO), 2001 National Research Council (NRC), 1999, 2001). These include the skin, developing fetus, liver and the cardiovascular, pulmonary, nervous, and endocrine systems. These effects are dose-related and primarily arise from oral exposure to arsenic, although inhalation of arsenic may also result in adverse health effects. The chronic effects from dermal exposure to arsenic are not known. 

Although trivalent inorganic arsenic, with its propensity for binding to the SH group of enzymes, is acknowledged to be more toxic to humans than pentavalent inorganic arsenic, it must be recognized that As can be converted to As in the human body as part of the reduction/biomethylation pathway of excretion... 

The modern period of chemotherapy, the treatment of disease by use of chemical substances, began with the work of Paul Fhrlich (1854-1916). It was known at the beginning of the present century that certain organic compounds of arsenic would kill protozoa, parasitic micro-organisms responsible for certain diseases, and Ehrlich set himself the task of synthesizing a large number of arsenic compounds, ill an effort to find one which would be at the same time toxic (poisonous) to protozoa irj the human body and non-toxic to the human host... 

Bones are actually living protein networks to which minerals attach themselves. Not aU of the minerals deposited on bones are essential to bone building. There are at least two dozen elements in bones that have no known function in the human body, as well as a handful of nonessential elements, such as boron, strontium, silicon, barium, bismuth, and arsenic (yes, arsenic), that are believed to do some good. Five toxic elements—lead, cadmium, mercury, polonium, and radium—are often found in human bones. As long as they are stabilized in the bones, they do no apparent harm. 

Arsenic is not an essential element for the human body, (a) Based on its position in the periodic table, suggest a reason for its toxicity, (b) In addition to hair, where else might one look for the accumulation of the element if arsenic poisoning is suspected ... 

Arsenic is not an essential element for the human body. Based on its position in the periodic table, suggest a reason for its toxicity. 

The other essential elements, called microminerals or trace elements, are mostly transition elements in Period 4, along with Mo and 1 in Period 5. They are present in the human body in very small amounts, some less than 100 mg. In recent years, the detection of such small amounts has unproved so that researchers can more easily identify the roles of trace elements. Some trace elements, such as arsenic, chromium, and selenium, are toxic at high levels in the body but are stiU required by the body. Other elements, such as tin and nickel, are thought to be essential, but their metabolic role has not yet been determined. Some examples and the amounts present in a 60-kg person are listed in Table 4.4. 

Despite its availability and current use, coal is not as widely used today as the other fossil fuels. Coal s major weakness is that it does not burn cleanly. It often contains trace amounts of other elements, including mercury, arsenic, and sulfur, and when it burns, it releases these toxic substances into the air. Over time, coal pollution builds up in the environment. Mercury released during coal combustion, for example, settles in water and builds up in the bodies of fish and shellfish. When these fish and shellfish are eaten by humans and other animals, harmful amounts of mercury can be ingested. In 2008, bluefm tuna served in expensive New York restaurants was found to contain unacceptably high levels of mercury. These fish eat smaller organisms in the ocean, and when these small organisms contain mercury, the toxic element becomes concentrated in the body of the tuna. 

The species that are the most hazardous to humans and other animals as poisons are those that have a toxic effect on the body and that are soluble in water or mild acid. Some species, like realgar, contain a potentially toxic element (arsenic), but have such a low solubility potential that their toxicity as a poison is considered to be low under normal circumstances. 

It is well known that a large number of chemical substances, including toxic metals and metalloids such as arsenic, cadmium, lead, and mercury, cause cell injury in the kidney. With metal-induced neurotoxicity, factors such as metal-binding proteins, inclusion bodies, and cell-specific receptor-like proteins seem to influence renal injury in animals and humans. It is of interest to note that certain renal cell populations become the targets for metal toxicity, while others do not. In fact, the target cell populations handle the organic and common inorganic nephrotoxicants differently. ... 

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