Pollution's Impact: Environment And Animal Health

Pollution is having a devastating impact on the environment and animals. The byproducts of human life, from sewage to industrial emissions, are polluting the air and water, becoming toxic to wildlife and ecosystems. Air pollution, for example, is causing significant behavioural changes in animals, from migration patterns to birds singing less. It is also causing higher mortality rates, with respiratory issues, heart problems, and cancer being common consequences. The environment is also suffering, with acid rain, for instance, reducing the number of accessible soil nutrients and damaging root and shoot systems.

Air pollution impacts animal behaviour and health

Air pollution has a detrimental impact on animal behaviour and health, causing significant behavioural changes and affecting their mortality risk.

Behavioural Changes

Air pollution can cause changes in animal behaviour, such as alterations in migration patterns, birds singing less, and bees abandoning their hives. Studies have shown that pollutants, including heavy metals and endocrine disruptors, directly impact animal social and mating behaviour. For example, chemical pollution has been found to impact polar bears' behaviours and hormonal balance, including their ability to search for food and mate.

Health Issues and Mortality Risk

Air pollution can lead to respiratory issues, heart problems, and cancer in animals, similar to humans. It can also weaken their immune systems, making them more susceptible to diseases. Pollutants impair organ function, endocrine function, and reduce reproductive success. Long-term exposure to air contaminants can increase the risk of neurodegenerative disorders. Additionally, air pollution contributes to the loss of biodiversity, with certain plant species essential for food and habitats being wiped out, further impacting animal health and survival.

Food and Water Contamination

Animals consuming contaminated food and water is another consequence of air pollution. Particulate-coated plants can cause arsenic poisoning, while lead poisoning in pets can lead to pneumonia and loss of appetite. Pesticides can cause breathing difficulties, drowsiness, muscle spasms, vomiting, and loss of coordination in animals. Air pollution also affects the supply and quality of food, with pollutants entering the food chain through bioaccumulation, where they increase in volume and concentration as they move up the food chain.

Impact on Ecosystems

The changes in animal behaviour and health due to air pollution can have dramatic effects on entire ecosystems. For example, the loss of certain fish species can lead to an increase in insect populations, benefiting some species that feed on insects, while disadvantaging fish-eating birds like ospreys.

Addressing air pollution and reducing the release of harmful chemicals into the environment are crucial steps to mitigate these impacts and preserve the health and biodiversity of our planet.

Climate change pollution and rising temperatures

Climate change, pollution, and rising temperatures are closely interconnected and have significant impacts on the environment and animals. Greenhouse gases, such as carbon dioxide, are the primary drivers of climate change and result from human activities like burning fossil fuels for transportation, heat, and power generation. These gases trap heat in the Earth's atmosphere, leading to a warming planet. The increase in global temperatures has already had observable effects, with the Arctic experiencing more rapid warming than any other region. This warming is due in part to positive feedback loops, where melting snow and ice expose more of the Earth's surface, leading to further warming.

The consequences of rising temperatures are far-reaching and influence both air quality and weather patterns. Warmer temperatures contribute to the formation of ground-level ozone, a major air pollutant and greenhouse gas. Ground-level ozone exacerbates lung diseases like asthma and can cause breathing difficulties, even in otherwise healthy individuals. It also has economic implications, resulting in lost workdays and high emergency room costs. Additionally, higher temperatures lead to more frequent and severe heat waves, droughts, and wildfires, which further degrade air quality. Wildfire smoke, in particular, poses a significant health risk, impairing visibility and causing respiratory issues.

The changing climate also affects the pollen season, with rising temperatures and carbon dioxide levels leading to longer pollen seasons and increased pollen production by plants. This, in turn, impacts both outdoor and indoor air quality, as higher pollen concentrations can trigger allergies and respiratory problems.

To address the issues of climate change, pollution, and rising temperatures, it is essential to reduce greenhouse gas emissions and mitigate the factors contributing to these issues. This can be achieved through regulatory initiatives, partnership programs, and individual actions, such as reducing the use of fossil fuels, transitioning to renewable energy sources, and improving air quality monitoring and management.

Persistent organic pollutants and bioaccumulation

Persistent organic pollutants (POPs) are toxic chemicals that have adverse effects on human health and the environment worldwide. They are easily transported by wind and water and can persist in the environment for long periods. POPs include synthetic chemicals such as PCBs, DDT, and dioxins, which can accumulate in the tissues of plants, animals, and people. As these chemicals move up the food chain, they become more concentrated through biomagnification.

POPs can be intentionally or unintentionally produced. Intentionally produced POPs are used in agriculture, disease control, manufacturing, or industrial processes. For example, PCBs have been useful in electrical transformers and as hydraulic fluids, while DDT is still used in some parts of the world to control mosquitoes that carry malaria. Unintentionally produced POPs, such as dioxins, result from industrial processes and combustion, including waste incineration and the burning of trash.

The impacts of POPs are far-reaching and long-lasting. They can disrupt endocrine, reproductive, immune, and nervous systems, cause behavioural problems, diabetes, thyroid issues, and even cancer. POPs also interrupt the food chain and can lead to birth defects and behavioural changes in plants and animals.

Bioaccumulation of POPs has been observed in the deepest ocean trenches, with contaminant levels higher than in nearby regions of heavy industrialization. This indicates that these pollutants are pervasive across the world's oceans and at full ocean depth. Bioaccumulation can also occur in terrestrial and aquatic species, ultimately entering the human body through consumption of fish, frogs, insects, meat, vegetables, and fruits.

To address the global concern of POPs, the United States and 90 other countries signed the Stockholm Convention in 2001. This legally binding international agreement aims to reduce or eliminate the production, use, and release of certain POPs. While many POPs included in the convention are no longer produced in the United States, the risk remains due to their persistence in the environment and transportation from other regions.

Excess nutrients and harmful algal blooms

Excess nutrients, specifically nitrogen and phosphorus, are the key elements of fertilizers. After fertilizers are used on farms, many of the excess nutrients not absorbed by plants run off into nearby streams, lakes, and rivers. These chemicals combine with excess nutrient runoff from lawns, septic systems, and livestock farms. All these excess nutrients can cause serious problems for our waterways.

Algae, which usually do not have enough nitrogen and phosphorus to grow in excess, now have more than enough nutrients to proliferate. This excess of nutrients removes the natural limitations on algae growth, allowing it to grow into giant blooms that block the sunlight underwater plants need to survive. These algal blooms can create underwater "dead zones" when they take oxygen from the water that fish and invertebrates need to survive. Every summer, a big dead zone caused by algal blooms forms in the Gulf of Mexico near where the Mississippi River enters the Gulf.

Harmful algal blooms (HABs) are becoming an increasingly common occurrence across the United States and the world. Blooms (large numbers or colonies) of algae or related organisms produce one or more toxins that can be dangerous to fish, wildlife, pets, and livestock. People can also be exposed to toxins through outdoor recreation activities and consuming contaminated drinking water. HABs can occur in both freshwater and coastal marine waters.

In fish, toxins (such as microcystins) are taken up by the liver, and at sufficient exposures, can affect liver function and cause liver damage. In some cases, fish kills have been associated with HABs. Wildlife can also be at risk from the toxins, both through direct ingestion or through consuming food containing the toxins. Though there have been few lab studies on impacts to birds, field studies have attributed deaths in songbirds, ducks, gulls, pheasants, and hawks to HAB exposures. Research in the Chesapeake region associated great blue heron deaths with toxic algae.

There are ongoing federal programs that protect water quality and limit the sources of nutrient runoff that contribute to HABs. These include the Waters of the U.S. Rule, which will ensure adequate protection of additional wetlands to help reduce nutrient runoff into our rivers and lakes, and the U.S. Farm Bill, which includes conservation programs targeted at priority watersheds to reduce nutrient runoff from fields.

Mercury and other heavy metals

Once emitted into the air, mercury falls back down to Earth, accumulating in our waters and soils. Bacteria then transform it into methylmercury, a highly toxic form that builds up in the tissues of wildlife and people. Methylmercury is a central nervous system toxin, and exposure to it can cause severe neurological effects, as seen in the infamous case of Minamata, Japan, where birds experienced extreme difficulty in flying and exhibited other abnormal behaviours. It can also damage the kidneys, which are the organs most vulnerable to harm from inorganic mercury.

Methylmercury poses a particular risk to the developing foetus, as it can easily cross the placental barrier and harm the developing nervous system. In birds, adverse effects on reproduction can occur at egg concentrations as low as 0.05 to 2.0 mg/kg (wet weight). Additionally, mercury can cause reduced fertility, slower growth and development, and abnormal behaviour in wildlife. Some studies have also suggested a link between methylmercury and cancer in humans, although the results are inconclusive.

Mercury is not the only heavy metal that poses a threat to the environment and wildlife. Other common heavy metal pollutants include arsenic, cadmium, chromium, copper, nickel, and lead. These metals enter our waters, soils, and atmosphere due to the rapid growth of the agriculture and metal industries, improper waste disposal, fertilisers, and pesticides. They can affect biological functions and growth and accumulate in various organs, causing serious diseases such as cancer.

Lead, for example, can cause neurodevelopmental effects in children and is toxic to plants, animals, and microorganisms. Young fish are particularly susceptible to lead poisoning, exhibiting symptoms such as spinal deformity and blackening of the caudal region. Cadmium is another toxic heavy metal that can cause pulmonary irritation, kidney disease, bone weakness, and possibly various types of cancer. It is toxic to plants, animals, and microorganisms, accumulating mainly in the kidneys and livers of vertebrates and invertebrates.

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