Stream Pollution: High Ph And Its Causes

The pH of a stream is a measure of how acidic or basic it is. A pH of 7 is considered neutral, and most organisms can only tolerate a pH close to 7. If the pH is too high or too low, it can be extremely harmful to the stream's ecosystem. While natural factors can affect the pH of a stream, human activity can also have a significant impact. This paragraph will discuss the pollutants that cause high pH levels in streams, also known as alkalinity.

Industrial and agricultural runoff

Agricultural Runoff

Agricultural runoff occurs when excess chemicals from fertilizers and pesticides are washed off fields and into nearby water bodies during rainfall or irrigation. Nitrogen-based fertilizers, which are commonly used to maintain crop yields, can run off into nearby streams and rivers. This increases the nitrogen content in aquatic ecosystems, leading to reduced water quality and excessive algal growth, which, in turn, decreases oxygen levels in the water.

Agricultural runoff can also introduce phosphorus into water systems. Phosphorus is a primary nutrient for algae, and its presence in high concentrations can lead to eutrophication, where excessive algae growth chokes a water body, further depleting oxygen levels and harming aquatic life.

Additionally, animal waste from livestock farming is a significant contributor to agricultural runoff. Manure contains high levels of nutrients, pathogens, and organic matter, which can contaminate water bodies during rainfall or irrigation. These contaminants can pose serious health risks to humans and other organisms in the water, including bioaccumulation and biomagnification of chemicals in aquatic organisms, which then impacts predators and humans higher up in the food chain.

Industrial Runoff

Industrial runoff can also cause high pH levels in streams. Certain industries, such as cement, asphalt, and soap manufacturing, often use lime, lye, or sodium hydroxide in their processes. The runoff from these industries can increase the pH of nearby water sources, making them more alkaline.

Mining operations, particularly coal mining, can produce acidic runoff and groundwater seepage if the surrounding soil is poorly buffered. This acidic runoff can lower the pH of nearby streams, making them more acidic.

Furthermore, wastewater discharge from industrial processes can also affect pH levels. For example, wastewater containing detergents and soap-based products can cause a water source to become too basic, increasing the pH.

In summary, both industrial and agricultural runoff can introduce various pollutants that alter pH levels in streams. These changes in pH can have significant impacts on aquatic ecosystems and human health, highlighting the importance of properly managing these activities to minimize their environmental impact.

Wastewater discharge

The discharge of industrial effluents is a primary example of how wastewater can cause high pH in streams. When industries release untreated effluents from processes that require acids, such as metal plating, they can introduce acidic substances into water bodies. If these effluents are not properly neutralised or treated, they can significantly lower the pH of the receiving water, making it more acidic. This, in turn, can have detrimental effects on aquatic life and ecosystems.

However, it is important to note that wastewater discharge can also contribute to high pH levels in streams. This typically occurs when industries or households release wastewater containing alkaline substances. For example, detergents and soap-based products can increase the pH of water, making it more basic. This can disrupt the natural balance of aquatic ecosystems, affecting the health of plants, animals, and other organisms that depend on stable pH conditions.

Additionally, wastewater discharge can introduce pollutants that interact with pH to modify their toxicity. For instance, metals such as aluminium, copper, and zinc are commonly associated with low pH levels. As the pH decreases, these metals become more bioavailable, increasing their toxic effects on aquatic life. This complex relationship between pH and pollutant toxicity highlights the importance of effectively treating and managing wastewater discharge to maintain the ecological balance of streams.

Furthermore, wastewater discharge can also impact pH levels in streams through the introduction of nutrients such as nitrogen and phosphorus. While these nutrients are essential for plant growth, excessive amounts can lead to excessive algal growth, which, in turn, can deplete oxygen levels in the water. This can create a hypoxic or anoxic environment, posing a threat to the survival of aquatic organisms that depend on oxygen, further exacerbating the ecological imbalances caused by altered pH levels.

Nitrogen and phosphorous

Nitrogen and phosphorus are essential nutrients for plant and animal growth and nourishment. However, an overabundance of these nutrients in water bodies can have adverse health and ecological effects.

Nitrogen, in the forms of nitrate, nitrite, or ammonium, is a nutrient needed for plant growth. It is also required for achieving optimum yields of grain, forage, and other crops. Human activities such as crop harvesting and cutting down forests have disrupted the natural nitrogen cycle, leading to a decline in nitrogen levels in the soil. To compensate, farmers apply nitrogenous fertilizers, but this can result in an excess of nitrogen in aquatic ecosystems. This, in turn, leads to increased algal growth, reducing water quality and oxygen levels. Additionally, excess nitrogen in groundwater can be harmful to humans and livestock if consumed.

Phosphorus is another vital nutrient for all living things. However, similar to nitrogen, too much phosphorus can negatively impact aquatic ecosystems. Excess phosphorus stimulates the growth of algae and other aquatic plants, a condition known as eutrophication. This leads to reduced oxygen levels, the potential for harmful algal toxins, blockage of sunlight for other organisms, and degraded habitat conditions for aquatic life. Sources of excess phosphorus in water bodies include fertilizers, runoff from urban areas, leaking septic systems, and discharges from wastewater treatment plants.

Both nitrogen and phosphorus pollution in streams can lead to eutrophication, causing a decline in water quality and negatively impacting the plants, animals, and recreation values associated with the affected water bodies. It is important to manage the application of fertilizers and wastewater containing these nutrients to prevent their excessive accumulation in the environment.

Additionally, it is worth noting that while nitrogen and phosphorus can impact the pH of water bodies, the provided sources do not explicitly state that they directly cause high pH (increased alkalinity). Instead, they are primarily discussed in the context of nutrient pollution leading to eutrophication and other ecological consequences. However, it is still crucial to manage these pollutants to maintain the health and balance of aquatic ecosystems.

Metals and chemicals

Metals such as aluminium, copper, and zinc are common pollutants that can cause high pH levels in streams. Acid rain, which is caused by the reaction of water with nitrogen and sulphur oxides, mobilises and leaches these metals into groundwater and streams. This results in higher dissolved metal concentrations combined with low pH. As the pH decreases, the metals become more bioavailable, leading to greater toxic effects.

Agricultural and industrial runoff, as well as wastewater discharge, can introduce various chemicals into water sources, increasing or decreasing pH levels depending on the specific chemicals involved. For example, detergents and soap-based products can cause a water source to become too basic, leading to increased pH.

In addition, environmental factors such as soil composition can impact pH levels. If the soil around groundwater sources contains carbonate, bicarbonate, or hydroxide compounds, these minerals can dissolve and travel with the water, increasing its alkalinity.

High pH levels in water can have negative consequences for aquatic life. Even small changes in pH can shift the community composition of streams by altering the chemical state of pollutants, making them more toxic to aquatic plants and animals.

It is important to monitor and address high pH levels in streams to protect the health of aquatic ecosystems and ensure the safety of drinking water sources.

Soil and bedrock composition

The pH of streams is influenced by the chemical composition of the soil and bedrock through which the stream flows. The pH of freshwater lakes, ponds, and streams usually falls between 6 and 8, depending on the surrounding soil and bedrock.

Bedrock, a basic component of the environment, influences the availability of resources that can be exploited by microorganisms. A correlative study was performed to determine if variation in streambed microbial community structure in low-order forested streams could be linked to the chemical nature of the parental bedrock. The study found that while there were no significant differences in total microbial and photosynthetic biomass in the sediments, the sedimentary microbial community structure differed between the two bedrock types and was significantly correlated with stream water ion concentrations.

Furthermore, the quality of dissolved organic matter (DOM) is influenced by the microbial community, which in turn influences the quality of the DOM. The DOM quality and bedrock composition, through their influence on stream water chemistry, impact the microbial community structure in streambed sediments.

Soil composition can also influence the pH of streams. Acidic soils in the Amazon, for instance, cause many of the lakes and rivers to naturally have low pH values. The pH of water sources can also be affected by decomposing pine needles, which decrease the pH of the soil and any water that runs over it.

In addition, human activities can introduce pollutants that alter the pH of streams. Point source pollution, for example, can increase or decrease pH depending on the chemicals involved. These chemicals can come from agricultural runoff, wastewater discharge, or industrial runoff. Wastewater discharge containing detergents and soap-based products can cause a water source to become too basic.

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