Question

Surface water contains (a) only salt (b) organic matter (c) salt and organic matter (d) suspended impurity

Short answer

Surface water contains (c) salt and organic matter.

Step-by-step solution

Understand the Context

Surface water refers to all water naturally open to the atmosphere, such as rivers, lakes, and oceans. This type of water is distinct from groundwater because it is directly exposed to precipitation and contaminants.

Analyze Each Option

Consider each option provided: - (a) Only salt: Salt is typically found in saline water bodies like oceans, but surface water can also contain other substances. - (b) Organic matter: This refers to natural debris, like leaves and plants, that can be found in rivers and lakes. - (c) Salt and organic matter: Combines both elements, typical for saltwater rivers or estuaries. - (d) Suspended impurity: This can include particles like silt, sand, and clay which are common in moving waters like rivers and streams.

Apply Real-World Observation

Surface water is constantly interacting with the environment, making it subject to various inputs such as organic matters from plants and animals, salts from erosion, and suspended impurities from sediments.

Conclusion Based on Observations

From the analysis, option (c) 'salt and organic matter' aligns well with the description of surface water, as it often contains a mix of various substances including both salt and organic matter.

Key concepts

Organic Matter in Water

Organic matter in water is a crucial component of the ecosystem. It consists of natural debris, such as leaves, stems, and parts of plants and animals that find their way into rivers, lakes, and oceans. This matter is not just passive debris. It actively participates in the ecological chain of aquatic life.

As organic matter breaks down, it becomes a food source for microorganisms like bacteria and fungi. These microorganisms, in turn, serve as food for larger aquatic organisms, creating a stable food web. Moreover, the decay process releases important nutrients into the water. These nutrients, such as nitrogen and phosphorus, are beneficial for plant growth.

However, too much organic matter can be problematic. Excessive decomposition can deplete oxygen levels in water, leading to conditions like eutrophication. This can result in algae blooms, which disrupt aquatic ecosystems. Therefore, the presence of organic matter, while natural and necessary, must be balanced to maintain water quality and ecological health.

Salt in Water

Salt is a common component of surface water and plays a significant role in determining the water’s characteristics. While we often think of salt as the crystals we use on food, in water, salt refers to dissolved ions that come from minerals. The most common salt in water is sodium chloride, but there are many other salts present.

Salts in water can arise from natural processes like the weathering of rocks, where rainwater slowly dissolves salts present in the earth. Rivers can carry these salts into larger bodies of water such as seas and oceans. This process is why ocean water is salty.

However, not all surface water is equally salty. Freshwater bodies like lakes and rivers have much lower concentrations of salts compared to oceans. The difference in salt concentration affects the organisms that can live in these environments. Salt concentrations are carefully monitored, as high salinity can impact water treatment processes and the health of aquatic ecosystems.

Water Impurities

Water impurities encompass various substances that are not part of the water's natural composition. These impurities include suspended particles like silt, clay, and organic debris. Such substances are carried by moving water from place to place.

Suspended impurities can originate from a wide range of sources, such as soil erosion, runoff from urban areas, and industrial discharges. As a result, they can significantly affect the clarity and quality of water. For instance, high levels of suspended impurities can reduce light penetration in water, hindering photosynthesis in aquatic plants.

Managing water impurities is vital for maintaining healthy water systems. Processes like filtration are used to remove these particles in water treatment facilities. By doing so, we ensure clean water supplies and preserve the aquatic life that is sensitive to changes in their environment.