Toxic/Mercury Flashcards
What is Mercury ?
Elemental mercury is a shiny, silver-white metal that is a liquid at room temperature and is traditionally used in thermometers and some electrical switches.
What are the three types of mercury ?
Elemental Mercury(Hg0)
Inorganic (mercurous, Hg1+ or mercuric, Hg2+)
Organic (methyl-, ethyl-, or phenylmercury
What are the elemental mercury ?
Elemental mercury is liquid at room temperature. It is used in some thermometers, dental
amalgams, fluorescent light bulbs, some electrical switches, mining, and some industrial
processes. It is released into the air when coal and other fossil fuels are burned.
What are the sources of elemental one ?
a) Liquid form • medical and environmental measuring devises • disc batteries • fluorescent light bulbs • dental amalgam b) Vapour form • burning fossil fuels • manufacturing, processing, and mining
Exposure of Mercury ?
Exposure Pathways Respiratory (harmful vapours inhaled) • easily absorbed into bloodstream • easily crosses blood-brain barrier • oxidizes and deposits in nervous system
Placenta
• easily passes through placenta, accumulating in fetus
Skin
• minimally absorbed through intact skin
Gastrointestinal
• minimally absorbed through gut
What are clinical manifestions of mercyry ?
Clinical Manifestations Lungs (acute inhalation) • pneumonitis • respiratory failure Kidney is final target organ • mercury accumulates as body tries to clear toxin Significant prolonged or acute exposure • salivation • sweating • mouth ulcers • Erethism (red palms/soles) • emotional lability • memory impairment
People may be exposed when they breathe air containing elemental
mercury vapors. Vapors may be present in such workplaces as dental offices, smelting
operations, and locations where mercury has been spilled or released. In the body, elemental
mercury can be converted to inorganic mercury.
Inorganic mercury
are formed when mercury combines with other elements, such
as sulfur or oxygen, to form compounds or salts. Inorganic mercury compounds can occur
naturally in the environment. Inorganic mercury compounds are used in some industrial
processes and in the making of other chemicals. Outside the United States, inorganic mercury
salts have been used in cosmetic skin creams.
How are inorganic exposure ?
People may be exposed if they work where inorganic mercury compounds
are used.
disinfectant • antibacterial • antiparasitic • cathartic • diuretic
Exposure of inorganic ?
Sources
• Mercurous chloride (calomel)
• teething powder, cholera
Exposure of inorganic
Exposure Pathways Gastrointestinal • local irritant • can be very caustic • little systemic absorption unless the protective barrier compromised
Exposure Pathways
Skin
• poor systemic absorption unless
exposed to large amounts
Clinical Manifestations Caustic nature can break down skin or mucosa, leading to • kidney damage • neurological damage
Clinical manisfestions of inorganic
Clinical Manifestations Prolonged exposure may cause • peripheral neuropathy • hypersensitivity reactions • on skin or in kidney • - salivation • - sweating • - erethism
Pink disease
Manifestations: • - develops in young children • - an “anguished” expression, • and progressive loss of • speech, hallucinations, and • delirium. • - profuse sweating • - red, peeling skin • - swollen, clammy, and cold • hands and feet • - intense itching • - hair los
Acrodynia
painful extremities
What are the signs and symptoms of pink disease
Signs and Symptoms • Painful hands and feet • Pink (dusky progression) color to hands and feet • that fade at ankles/wrists • Nose and cheeks have scarlet hue • Profuse
Oraganic
(methyl,
ethyl,phenyl)
Methylmercury • used as a crop fungicide • ubiquitous in environment since microorganisms • methylate elemental mercury
Sources Ethylmercury • thimerosal used as an antiseptic and vaccine preservative Phenylmercury • -fungicide in latex paints
Sources of inoragnic
Sources Ethylmercury • thimerosal used as an antiseptic and vaccine preservative Phenylmercury • -fungicide in latex paints
Thimerosal (merthiolate)
Sources:
• Vaccine preservative, nasal spray, contact eye
solutions.
Health Effects:
• Exposure to Hg in utero and children may
cause mild to severe mental retardation and
mild to severe motor coordination impairment;
Exposure pathways
Gastrointestinal • almost completely absorbed in gut because of lipid solubility Nervous System • easily crosses blood-brain barrier has affinity for certain nervous system cells (methyl) Exposure Pathways Placenta • easily crosses placenta, entering fetal circulation Breast Milk • - easily accumulates and transferred in milk Respiratory • unstable phenyl-mercury bond can result in the inhalation of elemental mercury
Clinical manifistetion
Clinical Manifestations Neurological signs and symptoms most prominent • Weakness • Paresthesia • visual and auditory deficits • Tremor • coma Clinical Manifestations Children and fetuses exceptionally vulnerable • Seizures • psychomotor retardation • visual and auditory impairment
Inorganic
Congenital • Developmental delay • mental • Physical Blindness Deafness Muscle atrophy Seizures
Acquired
occure after bNumbness of extremities Lack of coordination • hands • gait • speech Weakness Sensory loss • touch • vision • hearing Seizuresirth
Solution - Organic mercury
Solutions (Treatment Summary) • Chelation therapy is the standard intervention for elemental and inorganic poisoning (eg. BAL, DMPS, EDTA, vitamin C) • However, chelating agents may increase the CNS organic mercury concentration.
Treatment
Treatment Summary) • Chelating agents increase the mercury excretion. • However, there is little evidence to show that chelation arrests or decreases the toxic effects of chronic mercury poisoning. Solutions (Treatment Summary) • Indications for chelation are not well established. • However, chelation is often used empirically in severe acute cases.
