Non-essential Trace Elements (Lead, Mercury and Arsenic) Flashcards
What items were lead commonly found in? Why has lead been taken out of many of these items?
petrol
paint
pipes
car batteries
lead is an industrial pollutant
How many mg’s of lead is found in the body and where is most of this located
2 mg
90% in skeleton
How much lead in micrograms/L is the maximum limit which can be contained in blood
250
50 in children
In 1918 which occupation showed 40% of employes had lead toxicity
painters and lead acid battery reconditioners
Lead toxicity leads to neurological disorders, erythrocyte damage and anaemia. What are the molecular changes in lead toxicity which causes these symptoms?
neurological disorders:
- Pb disrupts synapse formation and neurochemical development
erythrocyte defects/anaemia:
- Pb inhibits delta-aminolevulinic acid dehydratase which interferes with heme synthesis
Pb toxicity inhibits enzymes like ATPase by….
binding to functional groups of enzymes
Pb can block functions of which other elements?
Calcium
Iron
Zinc
Where does lead accumulate in the human body when at toxic levels
mammary gland (can be dangerous when breast feeding)
bones
Pb toxicity creates….. by…..
reactive free radicals by the Fenton reaction (can bind instead of iron) and by inhibiting antioxidant enzymes
What is the treatment of Lead toxicity
chelating agents (e.g. EDTA)
- excretion in urine
Where is mercury found in high concentrations
industrial pollutants
- coal burning
- fumigants and fungicides
amalgams (alloys)
- mixture of mercury and other metals (e.g. dental fillings)
Fish
- whale meat in Japan
present in sewage
- due to industrial waste
Why is mercury found in all human tissue even with no known exposure to mercury?
Bioaccumulation: the absorption rate of mercury in the human body is faster than excretion rates as the body doesn’t not have good methods to remove mercury
Mercury comes in a few forms. What is the toxicity of each of these forms?
element/ metallic (quicksilver) = low toxicity
organic (mercury and carbon) = highly toxic
inorganic = low toxicity
Liquid mercury is poorly absorbed by the gut. What are the ways it is absorbed?
skin
inhalation
What is the most dangerous mercury compound? What did the compound used to be commonly used in?
dimethylmercury
thermometers