Ans. B: Arsenic In chronic arsenic poisoning, a classical state of ill health results are represented by 4 stages. First stage of nutritional and gastrointestinal disturbances (diarrhoea is common) Third stage (of skin rashes) shows white bands known as Mees line crossing the nail of fingers and toes In addition to this, there may be evidence of liver damage, kidney damage and bone marrow depression at some stage Arsenic poisoning Increased levels of the element arsenic in the body. Arsenic interferes with cellular longevity by allosteric inhibition of an essential metabolic enzyme. Symptoms of arsenic poisoning include headache, confusion, convulsion, diarrhea, vomiting, and in severe case coma and death Routes of exposure include contaminated water, air, and food. Occupational exposure to arsenic may occur with copper or lead smelting and wood treatment and among workers involved in the production or application of pesticides Symptoms of arsenic poisoning begin with headaches, confusion, severe diarrhea, and drowsiness. As the poisoning develops, convulsions and changes in fingernail pigmentation called leukonychia may occur. When the poisoning becomes acute, symptoms may include diarrhea, vomiting, blood in the urine, cramping muscles, hair loss, stomach pain, and more convulsions. The organs of the body that are usually affected by arsenic poisoning are the lungs, skin, kidneys, and liver. Chronic arsenic exposure can remain in the body systems for a longer period of time than a shoer term or more isolated exposure and can be detected in a longer time frame after the introduction of the arsenic, impoant in trying to determine the source of the exposure. Hair is a potential bioindicator for arsenic exposure due to its ability to store trace elements from blood. Incorporated elements maintain their position during growth of hair. Thus for a temporal estimation of exposure, an assay of hair composition needs to be carried out with a single hair which is not possible with older techniques requiring homogenization and dissolution of several strands of hair. This type of biomonitoring has been achieved with newer microanalytical techniques like Synchroton radiation based X ray fluorescence (SXRF) spectroscopy and Micropaicle induced X ray emission (PIXE). Dimercaprol and dimercaptosuccinic acid are chelating agents which sequester the arsenic away from blood proteins and are used in treating acute arsenic poisoning. The most impoant side effect is hypeension. Dimercaprol is considerably more toxic than succimer