Animals' Impact On Water Pollution: Understanding Their Role

Animals, both on land and in water, are severely impacted by water pollution. Water pollution is caused by a variety of factors, including plastic waste, oil spills, agricultural runoff, and sewage, all of which have detrimental effects on aquatic ecosystems and the animals that inhabit them. Marine debris, such as derelict fishing lines and nets, can entangle and harm marine animals, while plastic waste ingested by animals can lead to health issues and even death. Additionally, water pollution disrupts the delicate ecological balance, causing issues like eutrophication and harmful algal blooms, which further impact aquatic life and reduce biodiversity. The accumulation of toxins in the water, such as heavy metals and pesticides, can lead to health issues and reproductive problems in animals, with consequences that reach far beyond the affected animal.

Plastic ingestion

A study of mussels from UK waters found that 100% of the samples contained microplastic pieces. This is concerning because, as biofiltering organisms, molluscs, ascidia, and zooplankton can accumulate a high number of microplastic particles in their bodies. These particles can then be passed along the food chain to other animals. For instance, a study found that an average fish carries 35 microplastic particles in its gastrointestinal tract.

The ingestion of plastic can lead to intestinal blockages and damage, causing the unnecessary deaths of many land animals. For example, in Periyar, India, a wild elephant died from ingesting plastic waste discarded by pilgrims. Marine animals also face the risk of starvation, injury, and suffocation from consuming plastic. Seabirds, in particular, may struggle to regurgitate plastic pieces, and some species have been observed feeding plastic to their young. It is estimated that plastic debris kills more than a million seabirds annually.

Furthermore, microplastics can absorb toxins, which then transfer to the fatty tissues of animals that ingest them. This bioaccumulation of toxic chemicals in plastics poses a significant threat to marine apex predators like great white sharks and orcas. As primary consumers and humans consume contaminated fish, microplastics enter our food chain and bloodstream.

The impact of plastic pollution extends beyond marine life, as plastic waste can contaminate the soil and groundwater that land animals rely on. Chlorinated plastic, such as plastic food packaging and medical devices, can release harmful chemicals into the surrounding soil and groundwater. This leads to a decrease in species that live below the surface, such as mites, larvae, and other tiny creatures, resulting in less fertile soil and land.

Oil spills

The toxicity of oil poses another significant threat to animals. Oil contains various toxic compounds, and animals can ingest it when they attempt to clean themselves, leading to poisoning. Marine mammals, sea turtles, and birds are also at risk of inhaling oil fumes at the surface, which can cause severe health issues and even death. The impact of oil spills on wildlife can be widespread, with some spills affecting hundreds or even thousands of animals.

The effects of oil spills can persist for extended periods, depending on the type of oil. Lighter oils are more acutely toxic and can cause immediate harm to animals and plants. On the other hand, heavier oils, such as bunker oils used to fuel ships, may remain in the environment for months or years if not properly removed. While heavy oils are generally less toxic, they can still smother organisms and lead to long-term health issues, such as the development of tumors.

The Exxon Valdez oil spill in 1989 is a stark example of the devastating impact on wildlife. This single event killed billions of salmon and herring eggs, 250,000 seabirds, 22,800 sea otters, hundreds of seals and bald eagles, and potentially dozens of killer whales. Some species affected by this spill have yet to recover fully, even decades later.

Heavy metals

The presence of heavy metals in water can cause metal uptake and accumulation in aquatic species, such as fish. Studies have shown that heavy metals can impact the embryonic development of fish and cause chronic stress, weight loss, and reduced size. This, in turn, affects their ability to compete for food and habitat. Additionally, heavy metals can contaminate the food chain, reaching humans through the consumption of fish and other seafood.

The toxicity of heavy metals can lead to various health issues in animals and humans. Exposure to heavy metals has been linked to acute poisoning, reproductive failure, and immune suppression, as well as chronic and acute toxicity. Heavy metal poisoning can also cause liver and renal dysfunction, dermatological issues, and potentially malignancies. Some of the most toxic heavy metal ions include As (III), Cd (II), Cr (VI), Pb (II), Ni (II), Hg (II), and Cu (II).

To address the issue of heavy metal pollution in water, several methods have been developed to remove them from wastewater. Conventional approaches such as ion exchange, reverse osmosis, membrane filtration, and chemical precipitation have been effective in removing heavy metals. However, these methods often come with high operational costs and generate secondary pollutants during water treatment. As a result, there is a growing focus on developing cost-effective and eco-friendly bioremediation techniques, such as biosorption, bio-reduction, and phytoremediation.

Pesticides

Agricultural runoff, laden with pesticides, enters waterways and causes nutrient pollution. This leads to excessive algae blooms, creating "dead zones" that lack sufficient oxygen to support aquatic life. The build-up of toxic elements in waterways can impact animals that depend on marine organisms for food, and the collapse of aquatic ecosystems can have unpredictable effects on land-dwelling animals as well.

The impact of pesticide pollution on animals can be direct or indirect. Some animals may be sprayed directly, while others consume plants or prey that have been exposed to pesticides. Pesticide exposure can alter an organism's behaviour, impacting its ability to survive and reproduce. For example, exposure to certain pesticides can impede birds' ability to sing, making it difficult to attract mates.

The degradation of water quality by pesticides has significant human health implications. Ingestion of contaminated water or consumption of food exposed to pesticides can lead to health risks, including DNA damage and immune system deficiencies. Implementing sustainable farming practices, such as reduced pesticide use and proper waste management, is crucial to mitigating the impact of pesticide pollution on water sources and the animals that depend on them.

Marine debris entanglement

Marine animals, such as whales, dolphins, seals, sea lions, and sea turtles, frequently become entangled in fishing gear and other marine debris. This entanglement can lead to drowning, starvation, physical trauma, and infections. The gear can cut into their flesh, causing deep wounds and providing an entry point for pathogens. Smaller animals may drown immediately if the gear is large or heavy, while larger whales may pull the gear off the ocean floor but still face risks from exhaustion and infection.

Entanglement in marine debris can also impair the animals' ability to escape from vessels, increasing the risk of vessel strikes. This problem is not limited to large animals, as even smaller creatures like sea turtles, seals, porpoises, and smaller whales can become entangled and face immediate danger. The impact of entanglement extends beyond the individual animals, as it can lead to a decline in specific species and disrupt the delicate ecological balance that has evolved over millions of years.

Responders have developed specialized tools and techniques to disentangle whales and other marine animals, often using small inflatable rescue boats for safety. They employ satellite technology to track entangled animals and relocate them if initial disentanglement efforts are unsuccessful. Authorized responders with the necessary training, experience, and equipment are crucial to safely freeing these marine animals from life-threatening situations.

The issue of marine debris entanglement has attracted considerable media and public attention, especially with the publication of images depicting seabirds, marine mammals, and fish entangled in abandoned or lost netting. This has sparked sympathy and anger worldwide, highlighting the urgent need to address the problem of marine debris and reduce the harm it causes to marine life.

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