Heavy Metal Pollution Flashcards
Are trace metals a source of pollution?
Yes, they are the main source of metal toxicity in the environment
What are trace metals defined as?
Occurring at 1000 parts per million or less in the earth’s crust
Are all metals toxic and persistant?
All metals are persistent but not all are bio-accumulative or toxic
What are the three groups of metals that are of biological concern?
-Light metals (< 5 gcm-3)
-Transitional metals
-Metalloids (Heavy metals >gcm-3)
What are some examples of light metals?
Sodium, potassium, calcium
-Normally transported as mobile cat ions in aqueous solutions
What are some examples of transitional metals?
Iron, copper, cobalt
-Essential at low concentrations but may be toxic at high concentrations
What are some examples of heavy metals?
Mercury, lead, arsenic,
-Not required for metabolic activity and toxic at low concentrations
What does PBT stand for?
Persistent, Bio-accumulative and toxic
What nutrient metals are not PBT?
Iron (Fe), Manganese (Mn), Vanadium (V)
What are five nutrient metals that are persistent, bio-accumulative and toxic?
Copper (Cu), Nickel (Ni), Zinc (Zn), Selenium (Se), Chromium (Cr)
What are five non-nutrient metals that are PBT?
Antimony (Sb), Arsenic (Ar), Cadmium (Cd), Mercury (Hg) Lead (Pb)
What is the most toxic heavy metal?
Mercury (Hg)
List natural sources of heavy metal pollution
-Normal geological formations (ore formations)
-Weathering of rock and leaching
-Degassing (Hg and Volcanoes)
-Forest Fires
-Food and drinking water
What is degassing?
Is the removal of dissolved gases from liquids, especially water or aqueous solutions
What are some anthropogenic sources of heavy metals?
-Burning fossil fuels
-Mining, smelting and processing metal ores
-Discharging industrial, agri. domestic waste and effluent
-Application of pesticides fungicides and fertilisers
-Paints, dyes, leather, rubber, textiles etc.
-Oil spills
What heavy metal is present in haemocyanin (molluscs and crustaceans respiratory pigment)
Copper (Cu)
What heavy metal is present in haemoglobin? (vertebrates and invertebrates )
Iron (Fe)
What heavy metal is in respiratory pigments of tunicates?
Contains V (Vanadium)
How do organisms obtain essential heavy metals?
-Uptake is by passive diffusion
-Active transport systems
-Food and water
-At higher doses than those needed for nutrition, metals can be toxic