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Description
At the end of this activity, students should be able to: – explain the composition and properties of natural water: oxygen content, pH, hardness, content of ionic compounds – explain the toxic properties of heavy metals, give examples of poisoning by heavy–metal ions contained in water – discuss the positive and negative effects of using pesticides – explain the eutrophication of water by excess phosphate – describe the purification of tap water and the treatment of sewage.