Lecture 4 Flashcards
Mercury is:
-A natural occurring element in crust. found in air, water, and soil
-Liquid at Room temperature (heavy odorless silver liquid)
-Vapor is hazardous
Inorganic Mercury: Hg 2+
Organic Mercury: MeHg
Elemental Mercury
Inorganic Mercury
-illegal in US
-Combination of mercury with other elements (sulfur, oxygen)
-can occur naturally
-used in some industrial processes (skin care or cosmetics in some countries)
Organic mercury
-formed when mercury combines with carbon
-Found in soil and water organisms (MeHg = methylmercury)
-There is also ethylmercury and dimethylmercury)
-Found in fish, some antiseptics, but not in vaccines anymore
Mercury can do what in the environment?
Biomagnify and bioaccumulate:build up through organisms lifetime
Mercury is present in blood and urine of most of the population
What are some factors that impact the health effects and severity of mercury exposure?
-All humans are exposed to some level of mercury (low levels through food and high levels through acute exposure)
Health effects and severity are based on:
* Dose
* Duration
* Age /developmental stage
* Exposure route
* Type of mercury
Exposure routes of Mercury:
1) Air (inhalation)
2) Water (ingestion and dermal absorption)
3)Soil (Ingestion and Dermal absorption)
4) Food (ingestion)
Chronic exposure of Elemental mercury mainly impacts the:
Nervous system
-Tremors
-Erethism (memory loss, insomnia, depression…)
inhaled vapor for weeks or years
Acute exposure of Elemental Mercury mainly impacts:
Lungs
-cough
-chest tightness and shortness of breath
-bronchitis and pneumonia
inhaled vapor once
Common symptoms of Inorganic Mercury poisoning:
Chronic Exposure: (skin application) Renal system: kidney failure
Acute exposure: (Ingestion of corrosive salts) Renal system: Decreased urination and kidney failure
Organic Mercury Toxicokinetics:
-Efficiently taken up by the GI tract (95%)
-Can cross BBB
-Accumulates in hair
Organic Mercury chronic exposure:
-Via food (high fish diet)
-Nervous system: paresthesia, ataxia, weakness, vision and hearing loss, tremors
Major difference between ethyl-Hg and methyl-Hg
-ethyl-Hg has a faster conversion to inorganic
-ethyl-Hg is less severe than methyl-Hg (methyl-Hg has a higher 1/2 life)
-ethyl is more renal injury and lower brain concentration
Diagnosis of Mercury poisoning
Blood test
Urine test
Hair levels
50 ug/L urine
10-20 ug/L blood
Treatment of mercury poisoning
-Start asap
-Monitor vital organs
-IV fluid replacement therapy for ingestion of inorganic mercury (endoscopic examination, GI decontamination)
-Lowering Hg concentration through hemodialysis and chelating agents
Chelating agents
DMSA and DMPS
Minamata Bay Disaster
-Japan
-fish were dying and plant life floating in water
-young girl admitted to hospital for neurological symptoms
-Serious brain disorder (inability to speak or eat, ataxia, numbness of limbs…)
Factory, Chisso, was producing high levels of Hg.
“dancing cats”: experimented on stray cats acting weird so fed fish to cats and they were getting the minamata symptoms
symptoms persisted long after exposure
Dimethylmercury
-more toxic than methylmercury
-Highly volatile, flammable, colourless liquid
-One of the strongest neurotoxins known
What is dangerous about mercury poisoning?
-There is a long latency period so people do not know they are exposed which delays treatment
-fetus is affected greatly
-Organic mercury is a lot more toxic
