Water Pollution: Understanding The Primary Contamination Categories

Water pollution is the contamination of water bodies, which has a negative impact on their uses. Water pollution can be categorised in several ways, depending on the source of the pollutant or the nature of the pollution. The main types of water pollution include surface water pollution, groundwater pollution, suspended matter, oil spillages, microbiological pollution, chemical water pollution, thermal pollution, and oxygen-depletion pollution. These pollutants can originate from various sources and significantly harm ecosystems, wildlife, and human health.

Groundwater pollution

Groundwater is a vital resource, providing drinking water for around 140 million people in the US alone. It is also an important source of water for irrigation. Groundwater starts as precipitation and, once it penetrates the ground, it continues to move, sometimes quickly, sometimes slowly, through the soil and rock.

Fertilizers and pesticides applied to farmland are easily absorbed into the ground or transported as runoff during rainfall. Waste from landfills and septic systems can also leach into the ground, and when these harmful chemicals are extracted from wells or boreholes, the quality of the water is compromised. Septic systems are supposed to slowly drain away human waste underground at a harmless rate, but an improperly designed, located, constructed, or maintained system can leak bacteria, viruses, household chemicals, and other contaminants into the groundwater.

Volatile organic compounds (VOCs) are a dangerous contaminant of groundwater, often introduced through careless industrial practices. Primary VOC pollutants found in groundwater include aromatic hydrocarbons such as BTEX compounds (benzene, toluene, ethylbenzene, and xylenes), and chlorinated solvents including tetrachloroethylene (PCE), trichloroethylene (TCE), and vinyl chloride (VC).

Prevention methods for groundwater pollution include applying the precautionary principle, groundwater quality monitoring, land zoning for groundwater protection, locating on-site sanitation systems correctly, and applying legislation. When pollution has occurred, management approaches include point-of-use water treatment, groundwater remediation, or abandonment as a last resort.

Surface water pollution

There are four main sources of surface water pollution: agricultural runoff, sewage/wastewater, oil pollution, and radioactive substances. Firstly, agricultural activities are a leading cause of surface water pollution, especially in regions with high agricultural demands, such as the Niger Delta in Nigeria. Fertilizers, pesticides, and animal waste can easily wash into waterways during rainfall, degrading water quality. Additionally, the use of fertilizers can block out sunlight, hindering the growth of underwater organisms and disrupting the ecosystem.

Sewage leaks and waste products from farms also contribute significantly to surface water pollution. These wastes often carry pathogens and waterborne diseases, posing serious health risks to humans and aquatic life. Furthermore, domestic wastewater, including pharmaceutical products, natural hormones, and plastic pollutants, is another primary source of surface water pollution, particularly in urban areas.

Oil pollution is another critical concern for surface water bodies. Oil spills and discharges from industrial operations or stormwater runoff can contaminate waterways, endangering aquatic life and rendering water toxic for human consumption. Additionally, surface water pollution can be attributed to radioactive waste generated by uranium mining, nuclear power plants, military weapons testing, and research activities involving radioactive materials.

The consequences of surface water pollution are severe, impacting drinking water supplies, aquatic ecosystems, and human health. It is important to address and mitigate surface water pollution through proper waste disposal, reducing plastic consumption, and implementing measures to prevent agricultural and industrial runoff from reaching water sources.

Microbiological pollution

Water pollution is the contamination of water by pollutants such as bacteria, parasites, chemicals, and trash, including plastic. One of the main categories of water pollution is microbiological pollution.

Sewage is the primary source of microbial pollution in water. The effluent of fecal matter, hospitals, industry, and cattle farms increases the bacterial load in a water body. Coliform groups of bacteria, such as Escherichia coli, are considered indicators of fecal contamination. Fecal streptococci and Clostridium perfringens are also used as indicators of fecal pollution.

The presence of microbial contamination in water can be assessed through various methods, including turbidity measurements, molecular (PCR-based) techniques, and biochemical oxygen demand (BOD) techniques. However, there is a growing need for faster and more reliable monitoring methods to address the increasing risk of water contamination due to climate change.

The lack of adequate water treatment systems in some developing and low-income countries further exacerbates the issue of microbiological pollution. This vulnerability, combined with proximity to pollution sources, puts these communities at a higher risk of water-related illnesses.

Chemical water pollution

Chemicals are the most common type of water pollutant. Many industries use chemicals that can end up in water systems, including metals and solvents from industrial operations, fertilizers and pesticides from agricultural activities, and chemicals from pest control companies. These chemicals can contaminate both soil and water systems, negatively impacting humans, livestock, and fish that depend on these environments.

In aquatic ecosystems, chemical water pollution is highly toxic to aquatic life, impeding growth, disrupting reproduction, and even causing death. Chemical pollution includes pesticides and fertilizers, as well as heavy metals and solvents used in industrial sites. These substances can be absorbed into the ground and transported through rainwater, eventually contaminating underground water sources.

Fertilizers, for instance, can block sunlight from reaching underwater organisms, hindering their growth. Additionally, fertilizers, pesticides, and heavy metals can increase the risk of cancer and cause reproductive problems, as well as impairing the functions of vital organs like the eyes, liver, and kidneys.

The Clean Water Act in the United States mandates that industries disclose the pollutants they release into drinking water sources. However, enforcement of pollution controls and disclosure requirements often fall short, allowing industries to discharge undisclosed chemicals illegally. This has led to dangerous experiments being conducted on communities, with a disproportionate impact on low-income and color communities.

To address chemical water pollution, it is essential to identify the sources of pollution, implement stricter regulations, and enforce accountability among industries. By doing so, we can protect both human health and the health of our rivers and waterways.

Thermal pollution

Water pollution is the contamination of water by pollutants such as bacteria, parasites, chemicals, and trash, including plastic. There are several categories of water pollution, including chemical water pollution, thermal pollution, and oxygen-depletion pollution.

For example, thermal pollution can increase the rate of metabolism in fish and damage larvae and eggs in rivers. It can also make metals more bioavailable, increasing the harm from nutrients and toxins. The increased temperature may not be tolerable for aquatic life, and it can also increase microbial growth, which further decreases dissolved oxygen.

To mitigate thermal pollution, careful storage of wastewater in ponds and reinjection into deep wells are effective methods. Additionally, addressing the issue at its source is crucial, such as improving the management of wastewater used for industrial cooling and power generation.

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