Canada has 171 billion barrels within its borders. However, nearly all of these reserves are located in Alberta's "sandpits," a terrain that makes the oil and gas harder to extract from the earth than it is in
Zn and Cu are essential elements, but excessive concentrations in crops might result in toxicity to humans [38,39]. Pb was previously associated with the usage of leaded fuels (gasoline with PbO4 addition). As this kind of fuel was phased out in most developed countries, the main sources ...