Water Pollution: Ph Imbalance And Its Ecological Impact

The pH of a body of water is a crucial indicator of water quality and is affected by various factors, including natural and human processes. Pollution, particularly from industrial and mining activities, can significantly impact the pH levels of water, making it more acidic or basic. This, in turn, has far-reaching consequences for aquatic life and ecosystems, as well as potential effects on human health. Understanding the relationship between pollution and pH is essential for assessing water quality and implementing effective management practices to mitigate the negative impacts of pollution on the environment and human well-being.

Acid rain

The effects of acid rain are wide-ranging and detrimental. In the environment, acid rain can harm water bodies, vegetation, and buildings. When acid rain is washed into lakes and streams, it can cause them to turn acidic, affecting the aquatic food chain and harming plants and wildlife, such as insects and fish. Acid rain can also detriment soil composition by stripping it of essential nutrients like calcium and magnesium, which are crucial for plant growth and maintaining healthy soil.

The corrosive nature of acid rain also poses challenges to human infrastructure. It can cause paint to peel, corrosion of steel structures such as bridges, and weathering of stone buildings and statues. Additionally, acid rain has been linked to potential impacts on human health, although the specific effects have not been elaborated on.

The issue of acid rain gained widespread recognition in the 1960s, particularly in Europe, and public awareness increased in the 1970s due to media coverage and research efforts. Since then, governments in Europe and North America have implemented regulations to reduce the release of sulfur dioxide and nitrogen oxide into the atmosphere, resulting in positive outcomes.

Industrial waste

Sources of Industrial Waste

• Mining and Industrial Operations: Acid mine drainage, coal mining, and coal-fired power plants are major sources of acidic wastewater. Sulfur-bearing rocks, acid-generating soils, and coal piles contribute to low pH levels.
• Agricultural and Industrial Runoff: Runoff from agricultural fields, golf courses, and industrial sites can contain lime-rich fertilizers or industrial wastes, impacting water pH.
• Emissions and Effluents: Atmospheric emissions from industrial sources, such as sulfur and nitrogen oxides, can lead to acidic deposition in water bodies. Effluents from industrial facilities, including metal plating plants, also contribute to increased hydrogen ion concentrations.

Effects on Water pH

• Acidic Conditions: Industrial waste can introduce high levels of hydrogen ions into aquatic systems, leading to decreased pH values. This can be detrimental to aquatic life, as acidic conditions can reduce dissolved oxygen levels and harm aquatic organisms.
• Heavy Metal Contamination: Wastewater from mining and industrial activities often contains high loads of heavy metals. Adjusting the pH of this wastewater is crucial for the chemical precipitation and removal of these toxic metals.
• Nutrient Content Alteration: Industrial wastewater can affect the nutrient content of natural water basins. This includes changes in phosphorus concentrations, which are regulated by both European and Romanian law.

Treatment and Mitigation

• PH Adjustment: Treating industrial wastewater often involves adjusting its pH to clarify and dispose of it properly. Chemicals like ALAR F201 and lime are used to treat a wide range of pH levels and remove contaminants.
• Chemical Separation: Flocculent chemicals are used in wastewater treatment to separate solids from the water. These chemicals have no direct effect on pH but help in the physical treatment process.
• Regulations and Monitoring: Laws, such as those in Romania and Europe, stipulate acceptable levels of total phosphorus in water bodies. Monitoring programs help assess water quality and ensure compliance with regulations.

Mining operations

One of the primary ways mining affects water pH is through acid rock drainage (ARD) or acid mine drainage (AMD). In open-pit mines, sulfides in rocks react with water and air to produce sulphuric acid. This process is enhanced by the bacteria Thiobacillus ferrooxidans, which accelerates acidification and oxidation. The resulting acidic runoff dissolves heavy metals like copper, lead, and mercury, contaminating streams, rivers, and other water bodies. Abandoned mines can also contribute to this issue, as water seeping out of them often becomes very acidic and contaminated with heavy metals.

Heavy metal pollution is another consequence of mining operations. Excavated rocks or exposed underground mines containing metals such as arsenic, cobalt, copper, cadmium, lead, silver, and zinc can leach these metals into nearby water bodies. While metals can move in neutral pH conditions, low pH conditions, such as those created by AMD, accelerate leaching. These heavy metals impact water chemistry, affecting pH, buffering capacity, and dissolved oxygen levels. Additionally, the presence of heavy metals in water can have adverse effects on aquatic life, including fish and macroinvertebrates, altering their behaviour and community dynamics.

Processing chemicals used in mining, such as cyanide or sulphuric acid, can also spill, leak, or leach into nearby water sources, causing further pollution. These chemicals are highly toxic to both humans and wildlife. Moreover, mining operations can lead to increased erosion and sedimentation, disturbing soil and rock during road construction and the creation of open pits. When heavy rain occurs, loosened topsoil is washed away, carrying sediments that pollute water bodies and harm aquatic organisms and vegetation downstream.

While mining is essential for industrial development and provides various advantages to societies, it is crucial to address its environmental impacts. Implementing stricter environmental regulations, adopting sustainable practices, and utilizing artificial intelligence for predictive modeling can help reduce pollution and ecological damage associated with mining operations.

Soil composition

Agricultural practices, such as the use of fertilisers, can significantly alter soil pH. Fertilisers like crushed sulfur and ammonium-based nitrogen fertilisers can decrease pH, making the soil more acidic. This increased acidity affects the availability of nutrients and chemicals in the soil water, influencing plant growth. When soils become too acidic, their ability to retain essential nutrients, minerals, and elements decreases, leading to leaching by water flowing through the soil. This reduces the availability of nutrients for plants and can have broader ecological implications.

The effects of acid rain on soil composition can have cascading consequences. Acid rain can leach aluminum from soil clay particles, which can be harmful to both plants and animals. It also removes essential minerals and nutrients, such as calcium, magnesium, and potassium, that are crucial for plant growth. This depletion of nutrients in the soil can have long-term impacts on the health and productivity of ecosystems, including forests, streams, and lakes.

Additionally, soil composition influences the movement of persistent organic pollutants (POPs) through a process called the grasshopper effect. While the specifics of this process are beyond the scope of my current sources, it highlights that soil composition is not just influenced by external factors but also plays a role in the propagation and dispersal of pollutants, potentially exacerbating their impact on water pH and the broader environment.

Water purification

Storage and Natural Biological Purification

Water from rivers can be stored in reservoirs for periods ranging from days to months. This allows natural biological purification to occur and is particularly important for slow sand filtration. Storage reservoirs also help maintain water supply during short droughts or transitory pollution incidents.

Filtration

Filtration is a physical process used to remove large particles and suspended solids from water. The first documented use of sand filters dates back to 1804, and this method has since been refined and widely adopted. Other types of filters, such as biologically active carbon filters, are also used.

Sedimentation

Sedimentation is another physical process that allows solid particles to settle and separate from the water, leaving clearer water above the settled particles.

Distillation

Distillation is a process that involves boiling water to separate it from its contaminants. The steam produced during boiling is then condensed back into pure water, leaving behind impurities.

Chemical Processes

Chemical processes, such as flocculation and chlorination, are used to disinfect water and remove microorganisms. Chlorination, for example, is used to minimise the growth of fouling organisms in pipes and tanks, although it has been discontinued in some places due to potential adverse effects. Other chemical treatments include the use of activated alumina and bone char filter media to reduce excessive levels of natural fluoride in source water.

Ultraviolet (UV) Light

UV light is an effective disinfectant that can be used to reduce bacteria, viruses, and protozoa in water. However, UV light is most effective in clear water and requires sufficient contact time with the water to achieve maximum disinfection.

PH Control

Maintaining the optimal pH level in water is crucial as it affects chemical reactions, microbial growth, and the effectiveness of treatment chemicals. High or low pH levels can indicate contamination and can have adverse effects on aquatic life and water quality. pH control methods include carbon dioxide injection to lower pH and aeration to increase pH by removing carbon dioxide. Regular monitoring and measurement of pH levels are essential for effective water treatment.

Frequently asked questions