Pollution's Impact On Endangered Species: A Critical Analysis

Pollution is a significant threat to endangered species, and human activity is a key driver. Climate change, deforestation, and pollution are causing an ongoing environmental-animal crisis, with a predicted loss of 4-10% of animal species by 2060-2080. Pollution affects both terrestrial and marine animals, with 430 species significantly impacted in the US alone.

Endangered species are particularly vulnerable to catastrophic events such as chemical spills or pesticide application. Pollution also increases the vulnerability of species to other threats, such as disease and competition.

One of the most harmful pollutants is mercury, a toxic heavy metal that accumulates in the tissues of wildlife and people. It is released into the atmosphere primarily by coal-fired power plants and waste incinerators. Mercury has severe reproductive and neurological effects on wildlife, impairing motor skills and hunting abilities.

Other pollutants, such as PCBs, DDT, and dioxins, are toxic chemicals that persist in the environment and bioaccumulate in the food chain. These chemicals can cause mutations and fertility problems in various species, including fish, alligators, and polar bears.

Agricultural practices, such as the use of fertilizers, also contribute to water pollution, leading to harmful algae blooms that create dead zones and threaten aquatic life.

To protect endangered species, it is crucial to address the underlying societal values and behaviors that contribute to pollution and implement measures to reduce the flow of pollutants.

Chemical pollution in water

Water pollution is a pressing issue that poses a significant threat to endangered species and the environment. Chemical pollution in water, in particular, has far-reaching consequences, with harmful substances contaminating rivers, lakes, and oceans, and endangering aquatic life.

Agricultural practices are a major contributor to chemical water pollution. The use of pesticides, herbicides, and fertilisers in farming can have detrimental effects when they enter water bodies. Excessive nutrients, such as nitrogen and phosphorus, from fertilisers, can cause algae blooms. These blooms deplete oxygen levels in the water, creating "dead zones" where fish and other aquatic organisms cannot survive. Additionally, the chemicals in pesticides and herbicides can accumulate in the tissues of plants and animals, leading to bioaccumulation and biomagnification in the food chain. This was evident in the case of the bald eagle, whose populations declined due to thin-shelled eggs caused by the accumulation of chemicals like DDT in their systems.

Industrial activities also play a significant role in chemical water pollution. Toxic chemicals, heavy metals, and pollutants released from factories and power plants can contaminate water sources, posing risks to both wildlife and humans. Mercury, for instance, is a highly toxic heavy metal that has been linked to reproductive and neurological problems in a wide range of wildlife species. Lead is another dangerous contaminant, affecting wildlife and threatening human health, especially through the use of lead-based ammunition and fishing tackle.

The use of chemicals in everyday household products, such as cleaning agents, cosmetics, and pharmaceuticals, also contributes to water pollution. These products can contain endocrine disruptors, which interfere with hormone functions in both wildlife and humans, affecting reproduction, development, and growth.

Furthermore, plastic pollution is a significant concern, with plastic waste being ingested by marine animals and causing blockages in their digestive tracts, often leading to death. Plastic debris can also be mistaken for food by seabirds, leading to fatal consequences.

The impact of chemical water pollution on endangered species is evident in the case of the Southern Resident orca population in the Pacific Northwest. These iconic killer whales are vulnerable to toxic industrial chemicals, which accumulate in their blubber. High levels of toxic heavy metals, such as mercury and cadmium, have been detected in their tissues, posing a threat to their health and reproductive success.

To address chemical water pollution and protect endangered species, it is essential to implement stricter regulations, improve waste management practices, promote sustainable agricultural and industrial processes, and raise awareness about the responsible use and disposal of chemicals.

Climate change

Many species will not be able to adapt or migrate fast enough to survive. Climate change is already causing species declines and threatening nature's services to humans, such as carbon sequestration and resilience to climate change. According to the IUCN, climate change currently affects at least 10,967 species on the IUCN Red List of Threatened Species, increasing the likelihood of their extinction.

The impact of climate change on species is complex and far-reaching. It affects their abundance, genetic composition, behaviour, and survival. For example, rising temperatures have led to ecological changes, such as the migration of Chinook salmon to Arctic rivers, and behavioural changes, such as earlier breeding times for North American tree swallows.

Additionally, climate change can alter competitive relationships between species, favouring invasive species and those with higher mobility. Global warming is likely to result in a loss of biodiversity, with ecosystems becoming dominated by pioneer species and invasive species that are more adaptable to changing conditions.

To enhance species survival, it is crucial to prioritise nature conservation and promote strategies for climate change adaptation. Reducing CO2 emissions is essential to mitigate the impact of climate change on species and ensure ecosystems continue to provide habitats and vital services to humans.

Agriculture and aquaculture

Agriculture

The use of pesticides in agriculture has been linked to the endangerment and extinction of many species. Since World War II, synthetic chemicals have been used to control pests, weeds, and fungi, and their use has become integral to agriculture and disease control. While these chemicals are credited with increasing crop production and saving human lives, they have also had disastrous side effects on wildlife species.

DDT, for example, is an organochlorine pesticide that was widely used in the post-war era and credited with saving millions of human lives from deadly diseases like malaria and typhus. However, by the late 1960s, it was discovered that DDT was causing reproductive failure in several bird species, including bald eagles, peregrine falcons, and brown pelicans. This led to most industrialized countries banning the use of DDT in the 1970s.

Other synthetic pesticides have been developed that pose lesser environmental threats, such as organophosphates, but they still have adverse effects on wildlife populations. The annual rates of overall pesticide application have not shown any signs of decreasing, so wildlife populations will continue to be affected by exposure to these chemicals.

Agricultural practices that have led to environmental contamination by toxic metals include the use of pesticides and fertilizers containing these substances and irrigation, particularly in dry regions. Lead, for example, was used as an anti-knock agent in gasoline, and its combustion resulted in widespread contamination of terrestrial and aquatic ecosystems. While the use of leaded gasoline has been curtailed in recent years, it still poses a threat to wildlife and human health.

Aquaculture

Aquaculture, the farming of aquatic organisms, has been criticized for its environmental impacts and is considered one of the most criticized activities worldwide. While aquaculture provides good quality and accessible food for the population and generates millions of jobs, it has also been accused of causing environmental, social, and economic problems.

One of the main negative impacts of aquaculture is the destruction of natural ecosystems, particularly mangrove forests, to construct aquaculture farms. Mangrove forests are important ecosystems that serve as a source of organic matter, nursery areas for many aquatic species, and refuge for birds, reptiles, and crustaceans. However, aquaculture has been responsible for the deforestation of millions of hectares of mangrove forests in several countries.

Aquaculture has also been linked to the salinization and acidification of soils, pollution of water for human consumption, eutrophication and nitrification of effluent-receiving ecosystems, and the introduction of exotic species that can displace native species and spread pathogens. In addition, the use of hormones, steroids, antibiotics, and parasiticides in medication practices in aquaculture has caused imbalances in different ecosystems.

Furthermore, aquaculture's dependence on fishmeal and fish oil contributes to the collapse of fisheries stocks worldwide. Fishmeal supplies used for fish production have increased from 10% in 1988 to more than 30% in recent years. This dependence on fishmeal and fish oil is another practice in aquaculture that is not considered sustainable.

Strategies for Sustainable Aquaculture

To achieve sustainable aquaculture, several strategies have been proposed and proven effective. These include:

• Correct selection of farming sites and species: considering the vocation of the site, the carrying capacity of water bodies, and selecting native species over exotic ones.
• Implementation of the most adequate culture system: using floating or submerged cages instead of earthen ponds, and small ponds or farming structures for easier management.
• Improving feed and feeding practices: formulating feeds with precise nutrient concentrations and higher hydrostability, and promoting the use of natural feed.
• Adequate management of effluents: using settling lagoons, treatment with septic tanks, and bioremediation systems.
• Achieving certification of compliance with sustainability: following certification processes by organizations like the International Standards Organization (ISO) and the Food and Agriculture Organization (FAO).
• Improving research and legislation: evaluating the potential impacts of farms before installation and developing complete and concrete legislation to avoid environmental impacts.

Biological resource use

One example of biological resource use negatively impacting an endangered species is the case of the Southern Resident orca population in the Pacific Northwest. As top predators and keystone species, orcas are vulnerable to toxic industrial chemicals that can accumulate in their blubber. The highest levels of these chemicals are found in the tissues of apex predators such as orcas. These chemicals, known as Persistent Organic Pollutants (POPs), include Polychlorinated Biphenyls (PCBs), Polybrominated Diphenyl Ethers (PBDEs), Dichlorodiphenyltrichloroethane (DDT), and dioxins and furans.

The Southern Resident orca population is also affected by noise pollution, which stifles their calls and adds stress to the already imperiled population. However, laws implemented by Washington State have helped to reduce this type of pollution by requiring vessels to maintain a certain distance from the whales and reduce their speed when within a certain range.

Another example of biological resource use impacting endangered species is the decline of diadromous fish populations in the Garonne catchment in France. Water pollution, caused by population growth and industrialization, has been identified as a major factor contributing to the decline of freshwater biodiversity. Metals, agrochemicals, pharmaceuticals, and other industrial substances have been detected in the water column and sediments, posing a toxic risk to early life stages of fish species.

Plastic pollution

Marine animals are especially vulnerable to plastic pollution. About 11 million tonnes of land-based plastic waste enter the ocean each year, and this number is expected to triple in less than 20 years. Marine animals face two significant risks from plastic pollution: entanglement and ingestion.

Endangered marine species often get entangled in plastic litter, such as abandoned fishing gear or discarded six-pack rings, which can lead to injury or death. For example, the endangered Steller sea lion has suffered injuries and mortality due to entanglement in packing bands.

Additionally, marine animals mistake plastic for food, leading to plastic ingestion. A study found that 1,557 species worldwide, including many endangered ones, have ingested plastic. In 2019, a turtle hatchling was found dead with 104 pieces of plastic in its stomach. Plastic ingestion can block digestive tracts, pierce internal organs, and cause choking or starvation. It can also reduce the storage volume of the stomach, making it difficult for animals to eat.

Microplastics, tiny plastic particles less than five millimetres long, are another concern. They can pass through the digestive systems of marine animals without being expelled, leading to health issues. Microplastics have been found in hundreds of species, including 86% of all sea turtle species, 44% of seabird species, and 43% of marine mammal species. Tests have confirmed that microplastics can cause liver and cell damage and disrupt reproductive systems. For species like oysters, this can lead to a decrease in egg production, threatening population growth.

Land animals can also become entangled in plastic waste, hindering their mobility and making them more vulnerable to predators. They may suffer from overheating, suffocation, dehydration, starvation, and eventual death. Plastic can also cause deep wounds and even lead to limb loss, as seen in raccoons that get stuck in plastic ring beverage holders. Birds entangled in plastic may lose their ability to fly and hunt.

Microplastics are a concern for terrestrial animals as well. They leech into the soil and water sources from plastic waste in landfills, affecting terrestrial wildlife and the fertility of the soil. Chlorinated plastic can release harmful chemicals into the soil and groundwater, further contaminating the environment.

Addressing Plastic Pollution

To address the plastic pollution crisis, it is essential to reduce the production and consumption of single-use plastics and improve waste management and recycling systems. Banning plastic bags and adopting economic incentives, such as a Deposit Refund Scheme, can also help reduce plastic waste. Additionally, individuals can make simple switches, such as using reusable bottles and avoiding clothing made with synthetic fibres that shed microplastics during washes.

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