Earth Materials Lecture 11: Hazardous Minerals Flashcards
How many minerals contain Lead(Pb)?
559
What are the main Lead containing minerals?
Galena – sulphide
anglesite – sulphate
cerussite – carbonate
Mimetite – chloro arsenate
pyromorphite – chloro phosphate
vanadinite – chloro vanadate
Why is lead hazardous?
Heavy metals interfere with cellular activities.
* E.g. Pb substitutes for Zn in porphobilinogen synthase disrupting
heme and so blood production leading to anaemia (Jaffe et al., 2000;
Tanak and Tanaka, 2007; Korolnek and Hamza, 2014).
* Pb affects every organ in the body, especially the nervous system.
Interferes with Vitamin D synthesis and DNA transcription (Wani et al.,
2015).
* Can be stored in teeth and bones but released from bones.
* “No known safe blood lead concentration
How many minerals contain Mercury (Hg)?
103
What are the main Mercury bearing minerals?
Native Hg droplets
cinnabar – sulphide
balkanite – sulphide with Cu, Ag
Calomel – chloride
montroydite – oxide
grumiplucite – sulphide with Bi
Why is Mercury hazardous?
Hg salts are poorly absorbed due to their relative stability and insolubility.
- Corrosive to skin, eyes, gastrointestinal tract; possibly kidney failure if ingested (WHO, 2017).
- Gets into food chain as methylmercury via bacterial activity.
- This form is very readily absorbed and deposited in various tissues.
- Elemental Hg crosses the blood-brain barrier where it causes all manner of ills including mental health problems.
- It attacks the nervous and immune systems
- It alters protein functions; interferes with DNA transcription
How many minerals contain Arsenic (As)?
245
What are the main Arsenic bearing minerals?
Arsenopyrite – sulphide
realgar and orpiment – sulphides
enargite – Cu-As sulphide
Löllingite – Fe arsenide
scorodite – hydrous Fe arsenate
arsenolite - oxide
Why is Arsenic hazardous
Arsenic occurs as AsV (arsenate) and AsIII (arsenite) and is most toxic as the latter because more chemically bioactive and so enters cells more readily (IARC, 2011).
- Stored in the liver, kidneys, heart and lungs with lesser amounts in muscles and neuronal tissues.
- It inhibits 200 enzymes in cellular energy pathways, DNA synthesis and repair (Singh et al., 2011 and refs therein; Pelley, 2012).
- Because arsenate is a structural analogue of phosphate (Pelley, 2012).
- Can be mutagenic when in synergy with other molecules and UV, e.g. skin cancer.
- DNA strand breaks via oxidation; disrupts DNA by converting one amino acid to another; interferes with gene expression etc.
How many minerals contain Antimony (Sb)?
281
What are the main Antimony bearing minerals?
Native Sb
Stibnite – sulphide
jamesonite – sulphide with Fe
Stibiconite – hydrous oxide
kermesite – Sb-S oxide
tetrahedrite – sulphide with Cu
What are the variables and qualities that determine whether a mineral is safe to handle?
- Minerals containing toxic elements.
- Bioaccessibility of those elements.
- Depends on stability and hardness of mineral.
- Native Pb, Hg, As and Sb no-nos, highly toxic. Hg vapour, arsine
gas. - Low hardness minerals can be problematic because of powdered
form and inhaling or ingesting dust. - Do not grind the others!
- Fluorite can be problematic – unbound fluorine.
- Arsenolite high solubility.
- Otherwise, H>2 generally safe but always wash hands after use. Avoid dusts.
How many minerals/radioactive minerals contain Uranium(U)
291
What are the main Uranium bearing minerals?
Uraninite – oxide
pitchblende – oxide
brannerite – U titanite
Fergusonite – YREEsNb oxide
samarskite – YFeNb oxide
betafite – complex oxide Ca, Na, Ti, Nb
List secondary alteration products of radioactive minerals
Autunite - Ca phosphate
torbernite - Cu phosphate
cuprosklodowskite - hydrous Cu-silicate
Uranophane - hydrous Ca-silicate
boltwoodite – hydrous KNa silicate
curite – hydrous Pb oxide
