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Water Quality and Sustainability, Possible Questions - Coggle Diagram
Water Quality and Sustainability
Salinity
Cause
There are numerous causes for the level of salinity in natural water: The weathering of rocks and minerals, the evaporation of water which leaves salt behind, increasing the concentration, wind-blown salt from other oceans and seawater intrusion, along with human activities such as irrigation and industrial mining activities.
Effect
High salinity can lower biodiversity, as numerous freshwater species cannot survive in high salt content. Furthermore, salty water used for irrigation can cause soil to become hard and infertile, ineffective for plant growth.
Solution
Salinity in water can be improved one of two ways; Either precautionary measures can be taken, such as switching to drip irrigation to lower salt produced through human irrigation or bettering drainage systems, or through proceeding artificial measures such as electrodialysis, using electricity to draw out dissolved salts from the water.
Turbidity
Cause
Turbidity is caused by suspended or dissolved particles in water. These particles can be composed of material such as silt, clay, algae or other organic matter. These particles produce the cloudiness of the water which is referred to as turbidity.
Effect
Turbidity reduces the penetration of light, as the particles in the water block light from reaching through. This decreases the ability for submerged plants and algae to photosynthesise. Furthermore, the cloudiness of the water reduces visibility in the water, making it difficult for organisms to find food, shelter, or each other.
Solution
The process of flocculation, where a chemical is used to aggregate small particles into larger clumps in order to be filtered is how scientists lower the turbidity of water.
Hardness
Cause
Hardness of water is determined by the concentration of dissolved minerals such as calcium and magnesium ions. Naturally, water that flows through mineral rich rock formations (commonly groundwater) are often much harder.
Effect
Overly hard water can lead to the clogging of waterways or altered plant communities. On the other hand, overly soft water can weaken the shells and bones of organisms which inhabit said water. The ideal hardness for natural water is moderately hard, promoting biodiversity while keeping the water mineral rich. Slightly hard water also has other benefits, such as promoting plant growth and balancing water acidity.
Solution
The most effective solution to overly hard water is a reverse osmosis, filtering out minerals through a membrane. On a small-scale, this is highly effective, however this becomes more difficult in large-scale ecosystems.
pH
Effect
The ideal range for the pH of water is 6.5 - 8.5. Water outside this range can cause stress, reduced reproduction, and death for sensitive species. Furthermore, more acidic water allows for toxic metals such as aluminium, lead and mercy to dissolve, posing potential risk of poisoning to aquatic life.
Solution
There are no current large-scale solutions to fixing the pH of natural water. For artificial bodies calcite neutralisers or reverse osmosis systems can be implemented depending on the pH of the water.
Cause
Dissolved carbon dioxide forms carbonic acid in water, which lowers the pH, making it more acidic. Photosynthesis, respiration, and decomposition all contribute to fluctuating carbon dioxide levels.
Possible Questions
Does salinity change the electrical conductivity of water?
IV: Salt concentration
DV: Electrical conductivity of the sample
Hypothesis: Increasing NaCl concentration increases electrical conductivity of water linearly
CV: Type of salt, volume of solution, source of water, conductivity tester used, mixing method
Why: To determine the credibility of electrodialysis as a solution to salinity
How does the level of turbidity in the water affect the growth of water lilies?
Hypothesis: Increasing turbidity reduces the growth rate of water lilies
IV: Turbidity of water
DV: Relative growth rate (height/time)
CV: Plant species and source, initial plant age, soil type, source and amount, nutrient availability, water volume and source, turbidity production source
Why: To determine the significance of turbidity on aquatic organisms
Does boiling reduce temporary hardness in water?
Hypothesis: Boiling water for 10 minutes will reduce temporary hardness by at least 30%
IV: Time spent boiling
DV: Water hardness (CaCO_3/L)
CV: Amount of water, source of water boiling temperature, apparatus used to boil, measurement method
Why: To determine the potential of boiling as a solution to hardness