Human Activities: Freshwater And Ocean Pollution Sources

Human activities have a detrimental impact on water resources, causing freshwater and ocean pollution through a variety of means. These include industrial and residential waste, agricultural runoff, chemicals, plastic, and other pollutants. The overuse of pesticides and fertilizers in agriculture, as well as sewage from residential and industrial areas, ultimately finds its way into aquatic environments, degrading water quality and leading to the spread of infectious diseases. Additionally, plastic pollution, which has been an issue since the 1970s, poses a significant threat to marine life, with an estimated 70 to 80% of marine litter originating from inland sources and transported by rivers into the oceans. Climate change, deforestation, landscape changes, and urban growth also contribute to the degradation of freshwater and marine ecosystems.

Industrial, agricultural and residential waste

Industrial, agricultural, and residential waste are major contributors to water pollution. These human activities produce biotic and abiotic byproducts that contaminate and degrade the environment and surrounding ecosystems.

Industrial Waste

The production of industrial goods generates wastewater contaminated with toxic substances, including petroleum products, heavy metals, hazardous wastes, and sediments. Inadequate treatment and disposal of this wastewater result in the discharge of polluted water into nearby public waters, leading to the accumulation of toxins in aquatic sediments and groundwater.

Industries, such as factories, are often located near rivers, lakes, and seas, facilitating the discharge of untreated water. Emerging countries like China, India, and those in Africa and South America, are particularly vulnerable due to a lack of stringent environmental policies and consistent implementation.

Agricultural Waste

Agricultural management practices, including the use of pesticides, fertilizers, and animal waste, have a significant impact on water pollution. When it rains, these pollutants are washed into waterways, leading to nutrient pollution and eutrophication, which is more prevalent in winter.

Animal agriculture, in particular, contributes to bacteria and pathogens in manure, which can contaminate streams and groundwater if not properly managed. The use of genetically modified (GM) products, such as the Enviropig, has been suggested as a potential solution to improve digestive efficiency and minimize environmental damage caused by animal agriculture.

Residential Waste

Residential areas also contribute to water pollution through sewage and runoff. Low-income communities, often located near polluting industries, are at higher risk of exposure to waterborne pathogens, including bacteria and viruses from human and animal waste.

Overall Impact

Water pollution caused by these activities has severe consequences for aquatic life and biodiversity. It also affects drinking water sources, leading to health risks for humans, such as diseases like cholera, giardia, and typhoid.

Oil spills

Accidents involving tankers, barges, pipelines, refineries, drilling rigs, and storage facilities are the most common cause of oil spills. In addition, recreational boats can also release oil into the water or in marinas. Oil spills can also occur during the drilling and transportation of oil to refineries. While major oil spills from wrecked or damaged supertankers are now rare due to stringent shipping and environmental regulations, thousands of minor and several major oil spills related to well discharges and tanker operations are still reported each year.

The cost of oil spills is significant in both economic and ecological terms. The Oil Pollution Act of 1990 established that those responsible for oil spills can be held accountable for the cleanup and restoration of the affected area. This process, called Natural Resource Damage Assessment (NRDA), involves federal, state, and tribal agencies working together with the responsible party to select restoration projects with input from the public.

Plastic pollution

The majority of plastic pollution in the ocean is a result of littering and improper disposal of single-use plastic items such as food wrappings, plastic bags, bottles, and straws. These items end up in waterways and eventually make their way into the ocean. Rivers are the primary pathway for plastic to reach the ocean, and the Great Pacific Garbage Patch, located in the central North Pacific Ocean, is a stark example of the accumulation of plastic pollution. This garbage patch is larger than the state of Texas and contains a high concentration of plastic waste, including discarded fishing gear.

In addition to littering, industrial activities contribute significantly to plastic pollution. Improper manufacturing processes and industrial waste disposal release microplastics and plastic pollutants into water bodies. About 20% of ocean plastic pollution originates from industrial fishing and manufacturing. The production and use of plastic are widespread, with plastic being utilized in almost all consumer and industrial sectors, from packaging to construction and electronics.

The consequences of plastic pollution are far-reaching and detrimental. Firstly, it poses a significant threat to marine life. Marine animals, such as fish, turtles, seals, and crustaceans, suffer from entanglement and ingestion of plastic debris. The durability of plastic means that it persists in the ocean for long periods, breaking down into microplastics over time. These microplastics are then ingested by marine organisms, leading to intoxication and the transfer of toxins up the food chain, eventually reaching humans.

Moreover, plastic pollution affects human health directly. Microplastics have been found in human blood, placentas, and food and drink sources, including tap water, beer, and salt. The chemicals present in plastic are known to be carcinogenic and can cause developmental, reproductive, neurological, and immune disorders. Additionally, plastic pollution impacts socio-economic aspects, including tourism, fisheries, and trade systems.

Addressing plastic pollution requires a multifaceted approach. Reducing plastic production and consumption, improving waste management practices, and promoting recycling and reuse are essential. Global treaties, regulations, and initiatives are necessary to combat this transboundary issue effectively. Individual responsibility and lifestyle changes also play a crucial role in mitigating plastic pollution.

Chemical runoff

Agricultural practices also contribute to chemical runoff. Farmland runoff carries nutrients from fertilizers and animal manure into nearby water bodies, leading to nutrient pollution, which includes nitrates and phosphates. This type of pollution has become a significant issue due to the excessive use of fertilizers and the lack of proper waste management in the agricultural industry.

The consequences of chemical runoff are far-reaching and long-lasting. It not only affects water quality by making it unsafe for human consumption and recreational activities but also endangers aquatic life. The pollutants carried by runoff can harm fish and other creatures, block sunlight from reaching underwater vegetation, and contribute to the growth of algae, leading to low oxygen levels and the death of aquatic species.

Additionally, chemical runoff can lead to increased flooding in urban and suburban areas. As natural filters like forests and wetlands are replaced by impervious surfaces, the runoff has nowhere to go, often resulting in flooded streets and basements, causing repeated damage to homes and businesses.

To mitigate the impacts of chemical runoff, it is essential to implement measures that reduce and treat runoff before it enters water bodies. This can include creating "green infrastructure" and using permeable surfaces that allow water to penetrate and absorb into the soil, reducing the volume of runoff.

Noise pollution

One of the main sources of ocean noise pollution is shipping. Cargo ships can emit up to 190 decibels of noise, which is much louder than a plane taking off and comparable to the noise level of a rock concert. As ocean traffic is not evenly distributed, certain spots, such as travel routes and ports, experience significantly higher sound levels when vessels pass by. The bigger and faster a ship is, the louder it tends to be. Additionally, the propeller and cavitation generated by the propeller contribute significantly to the overall noise emitted by ships.

Oil and gas exploration and extraction activities also contribute to noise pollution in the ocean. These activities include drilling, placement of offshore structures, and production. The machinery and equipment used in these processes, such as airguns and seismic blasts, generate loud noises that can reach up to 135 decibels. These sounds can cause hearing damage to marine animals, particularly those that rely on sound for navigation and communication, such as whales and dolphins.

Military activities are another significant source of ocean noise pollution. The use of active sonar systems, with intensities reaching up to 240 decibels, has been linked to atypical whale strandings. Additionally, military detonations, weapon tests, and explosions create impulsive and explosive noises that can startle and harm marine life.

The impact of noise pollution on marine life is profound. It can interfere with the key life functions of marine species, such as communication, navigation, feeding, and mating. Marine mammals may change their vocal behaviour in response to noise, simplifying their vocal calls, increasing their volume, or shifting their sound frequency. In some cases, loud noises can cause hearing loss, distress, and even death. For example, sudden loud noises can cause whales to strand on beaches, leading to their death and disrupting the food chain for seafloor-dwelling animals.

Efforts to mitigate ocean noise pollution are underway. Organizations like IFAW and OceanCare are actively campaigning for noise reduction in the ocean. The European Union has set mandatory thresholds for underwater noise to protect species and habitats, and the International Maritime Organization (IMO) is working on revising guidelines for reducing noise emissions from shipping. Additionally, initiatives such as Blue Speeds aim to reduce ship speeds to decrease noise emissions and protect marine life.

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