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(c) Eutrophication in water may result from the addition of large quantities of nitrate fertilizers to it - Leaving Cert Chemistry - Question c and d - 2007
Question c and d
(c) Eutrophication in water may result from the addition of large quantities of nitrate fertilizers to it. Describe the processes occurring in the water leading to e... show full transcript
Worked Solution & Example Answer:(c) Eutrophication in water may result from the addition of large quantities of nitrate fertilizers to it - Leaving Cert Chemistry - Question c and d - 2007
Step 1
Describe the processes occurring in the water leading to eutrophication.
Answer
Eutrophication is primarily caused by the enrichment of water with nutrients such as nitrates and phosphates, often from agricultural runoff that includes fertilizers.
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Nutrient Enrichment: When nitrates from fertilizers run off from land into water bodies, it creates an environment rich in nutrients.
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Algal Blooms: This excess nutrient loading can lead to rapid growth of algae, known as algal blooms. Algae thrive as a result of the high nutrient concentrations.
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Reduced Light Penetration: As algal blooms proliferate, they block sunlight from penetrating the water, which affects other aquatic plants by obstructing photosynthesis.
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Decomposition: When the algae die, they are decomposed by microorganisms, which increases their populations exponentially.
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Oxygen Depletion: The decomposition process consumes dissolved oxygen in the water, leading to hypoxic conditions. When oxygen levels drop significantly, aquatic organisms struggle to survive.
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Ecological Impact: The overall effect of these processes results in a reduced biodiversity as many aquatic creatures cannot thrive in low-oxygen environments, disrupting the ecosystem.
Step 2
Explain how heavy metal ions are removed from large quantities of water.
Answer
Heavy metal ions can be effectively removed from water through several methods:
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Precipitation: This method involves adding chemical agents that react with heavy metal ions to form insoluble compounds which then settle out of the water.
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Adsorption: Various materials, such as activated carbon or specific clays, can adsorb heavy metal ions onto their surfaces, effectively reducing metal concentration in the water.
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Ion Exchange (Deionizing): This technique utilizes ion exchange resins that replace heavy metal ions with less harmful ions, rendering the water safer for discharge or use.
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Complexation: This method involves forming stable complexes with heavy metal ions, which helps in reducing their toxicity and aids their removal from water during subsequent treatment processes.
These techniques can be used individually or in combination, depending on the concentrations and types of heavy metals present in the water.