LEAD POISONING:
   • It is one of the most common diseases of toxic environmental origin and accounts for about 0.6% of the 
    global burden of disease. Lead is a naturally occurring heavy metal found in the earth's crust. It is soft, 
    malleable, and melts at a relatively low temperature. It is easily moulded and can be combined with other 
    metals to form alloys.
   • It is widely used in many products such as lead-acid batteries for motor vehicles, pigments, paints, solder, 
    stained glass, lead crystal glassware, ammunition, ceramic glazes, jewellery, and toys and in some cosmetics 
    and traditional medicines.
   • Mining, smelting, manufacturing and recycling activities, and the continued use of leaded paint, leaded 
    gasoline, and leaded aviation fuel (in some countries) are important sources responsible for environmental 
    contamination. Drinking water supplied through lead pipes or pipes joined with lead solder may contain lead. 
    Widespread use of lead has resulted in to extensive environmental contamination and health problems in 
    many parts of the world. Humans also suffer from lead intoxication through the food chain.
   • Lead is a cumulative toxicant (increasing in quantity in the body over many years) that affects multiple body 
    systems (neurologic, hematologic, gastrointestinal, cardiovascular, and renal systems).
    • Lead poisoning symptoms: The Signs and symptoms of lead poisoning in children include. 
     Developmental delay, Learning difficulties, Irritability, Loss of appetite, Weight loss, Sluggishness 
     and fatigue. Abdominal pain, Vomiting, Constipation, Hearing loss, Seizures, Eating things, such 
     as paint chips, that aren't food (pica). Newborns: Be born prematurely, Have lower birth weight, 
     have slowed growth.
    MERCURY POISONING 
    • Mercury is an element that is found all over the earth, in soil, rocks, and water. Even trace 
     amounts can be found in the air. The largest deposits on earth are as cinnabar (mercuric 
     sulfide). Mercury exists in several forms such as a liquid metal (quicksilver), as a vapor, and 
     in compounds (organic and inorganic). Scientifically, the symbol for mercury is Hg and its 
     element number is 80. Mercury has been used for centuries as a medicine, to make amalgams, 
     and in many industrial applications. Eventually, scientists, physicians and others realized the 
     various  forms  of  mercury  caused  health  problems.  The  problem  with  mercury  is  that  if 
     humans are exposed to it, depending on the amount (dose), route (ingestion, skin contact, 
     inhalation), and duration (time) of exposure, mercury can be toxic to humans. Some elemental 
     and chemical forms of mercury (vapor, methylmercury, inorganic mercury) are more toxic 
     than other forms. The human fetus and medically compromised people (for example, patients 
     with lung or kidney problems) are the most susceptible to the toxic effects of mercury.
    • Sign & Symptoms of Hg poisoning: The elemental mercury toxicity (which usually 
     occurs in the vaporized form) can cause: mood swings, nervousness, irritability, and other 
     emotional changes, insomnia, headache, abnormal sensations, muscle twitching, tremors, 
     weakness,  muscle  atrophy,  and  decreased  cognitive  functions.  High  exposures  of 
     elemental  mercury  can  cause  kidney  malfunction,  respiratory  failure,  and  death.  The 
     peripheral vision impairment, stinging or needle-like sensations in the extremities and 
     mouth,  loss  of  coordination,  muscle  weakness,  and  other  impairments  of  speech  and 
     hearing.  The  peripheral  vision  impairment,  stinging  or  needle-like  sensations  in  the 
     extremities and mouth, loss of coordination, muscle weakness, and other impairments of 
     speech and hearing.
     ARSENIC POISONING: It is a grey-appearing chemical element (atomic number 33, symbol As in the 
     periodic table) also termed a metalloid. It can exist in a metallic state in three forms (yellow, black, and gray; 
     with gray predominating) and in ionic forms. Arsenic is considered to be a heavy metal, and arsenic toxicity 
     shares some features with poisonings by other heavy metals. It has been used as a medicinal agent, a pigment, a 
     pesticide,  and  an  agent  with  intent  to  harm.  It  can  be  found  as  a  contaminant  in  food  and  water  sources. 
     Shellfish and other seafood, as well as fruits, vegetables, and rice; are the foods most commonly contaminated. 
     Arsenic  poisoning  typically  occurs  as  a  result  of  industrial  exposure,  from  contaminated  wine  or  illegally 
     distilled spirits, or in cases of malicious intent.
     • Sign & Symptom: Acute or immediate symptoms of a toxic level of exposure to arsenic may include the 
      following, Vomiting, Abdominal pain, Diarrhea, Dark urine (termed black water urine), Dehydration, Cardiac 
      problems,  Hemolysis  (destruction  of  red  blood  cells),  Vertigo,  Delirium,  Shock  and  Death.  Long-term 
      exposures to arsenic lower than toxic levels can lead to skin changes (darkening or discoloration, redness, 
      swelling and hyperkeratosis (skin bumps that resemble corns or warts). Whitish lines lines) may appear in the 
      fingernails. Both sensory and motor nerve defects can develop. Additionally, liver and kidney function may 
      be affected. Arsenic exposure over the long-term has also been associated with the development of certain 
      cancers, and arsenic has been classified as a carcinogen.
    • Chelation therapy (the use of drugs that selectively bind and effectively inactivate 
    substances) is usually begun quickly through an intravenous line. The drug and 
    the bound metal is then excreted through the urine.
    • Chelating agents useful as drugs are: Dimercaprol (BAL) Calcium disodium DTPA 
    Dimercaptosuccinic  Penicillamine  acid  (Succimer)  Desferrioxamine  Disodium 
    edetate Deferiprone Calcium disodium edetate
    • Antidote: The chelation drug of choice is Dimercaprol (also termed BAL in oil); 
    Succimer (DMSA) has also been used successfully, and Dimerval (DMPS) may 
    also work as a chelator.