pollution by heavy metal ions Flashcards
what are heavy metals exactly?
metals with high atomic masses
How do heavy metals enter water supplies?
they enter water supplies if industrial sewage enters a water supply or old batteries are dumped illegally.
Give 3 examples of heavy metals
cadmium,lead, mercury
what happens if heavy metals build up in our bodies?
they cause harm, i.e. birth defects and even death
How are heavy metals excreted from our bodies?
they are excreted by our bodies in our urine and so do not get the chance to build up to toxic levels
the impacts of heavy metal pollution on living organisms are very serious.
Describe heavy metals (their impacts/effects/traits) (6)
heavy metals are bio-accumulative, toxic at high concentrations, have neurological impacts, and some are carcinogenic.
they can also interfere with chemical processes by poisoning chemical catalysts and can impact on biochemical processes by interfering with enzyme reaction
How do heavy metals interfere with chemical processes?
they can also interfere with chemical processes by poisoning chemical catalysts and can impact on biochemical processes by interfering with enzyme reaction
Why are heavy metals serious environmental, economic and social impacts associated with heavy metal pollution?
heavy metals are bio-accumulative, toxic at high concentrations, have neurological impacts, and some are carcinogenic.
they can also interfere with chemical processes by poisoning chemical catalysts and can impact on biochemical processes by interfering with enzyme reaction
How are heavy metal ions usually removed from water/
by precipitation
e.g. lead ions are reacted with chloride ions to form insoluble lead chloride
Pb^2+ + 2Cl^- —> PbCl2↓
What are the EU limits for the following:
nitrates
phosphates
mercury
lead
cadmium
nitrates = 50ppm
phosphates = 2.2ppm
mercury = 1ppm
lead = 50ppm
cadmium = 5ppm
How is mercury precipitated out of the water?
by adding sulfide salts
