Ocean Pollution: Impacting Air Quality And Our Health

Ocean pollution and air pollution are two of the most pressing environmental issues facing the planet today. While the impact of air pollution on the oceans is complex, it is clear that the two are connected. Air pollution can cause ocean pollution, which in turn can have a detrimental effect on air quality. Atmospheric deposition is the process by which pollutants are deposited into the ocean, with nitrogen, mercury, combustion emissions, pesticides, and other heavy metals being among the most harmful air pollutants to ocean health. These pollutants can cause short-term and long-term damage to ocean ecosystems and biodiversity, which can have a knock-on effect on air quality.

Atmospheric deposition of nitrogen

Nitrogen is a naturally occurring element that is essential for the growth of all living organisms. Atmospheric deposition of nitrogen is one of the many ways in which humans influence the ocean. Fossil fuel combustion and agriculture result in the atmospheric deposition of nitrogen to the coastal and open ocean near major source regions in North America, Europe, and South and East Asia. This deposition can have significant effects on the ocean's productivity and carbon storage.

The atmospheric deposition of nitrogen can stimulate the explosive growth of plants and algae in aquatic systems. This can lead to a depletion of oxygen levels when the excess plants and algae die and decompose. In addition, atmospheric inputs of nitrogen in the form of dissociation products of strong acids (HNO3 and H2SO4) and bases (NH3) alter surface seawater alkalinity, pH, and inorganic carbon storage. The decrease in surface alkalinity drives a net air-sea efflux of CO2, reducing surface dissolved inorganic carbon (DIC).

The impacts of atmospheric nitrogen deposition are particularly significant in coastal waters, where the ecosystem is more vulnerable to human impacts such as nutrient fertilization, pollution, overfishing, and climate change. In these regions, alterations in surface water chemistry from anthropogenic nitrogen deposition can have severe implications for mankind. For example, the decrease in pH caused by nitrogen deposition can negatively impact a range of benthic and pelagic organisms that form calcareous (CaCO3) shells, such as corals, coralline algae, and foraminifera.

Furthermore, atmospheric nitrogen deposition can influence the productivity of the ocean by providing a limiting nutrient. The northern Indian Ocean, for instance, has long been presumed to be nitrogen-limited, suggesting that atmospheric nitrogen deposition could have large integrated impacts on its productivity. However, it is important to note that the nutrient dynamics in this region are complex and relatively poorly studied.

Overall, the atmospheric deposition of nitrogen is a significant factor in how ocean pollution can impact air quality. By altering the ocean's productivity, carbon storage, and seawater chemistry, atmospheric nitrogen deposition can have far-reaching effects on the Earth's climate and biosphere.

Ocean acidification

The increased acidity of the ocean has significant impacts on marine life, particularly shellfish and calcifying organisms. The formation and maintenance of shells and skeletons in creatures like clams, mussels, oysters, and corals rely on the availability of carbonate ions. As ocean acidification progresses, the decrease in carbonate ions affects their ability to build and maintain these structures, with some shells even beginning to dissolve. This has implications for the entire marine food web, as pteropods, a type of tiny sea snail, are an important food source for various organisms, from tiny krill to whales.

The impacts of ocean acidification extend beyond marine ecosystems, affecting human health and well-being. It can lead to malnutrition and poisoning through altered food quantity and quality, respiratory issues due to impaired air quality, mental health impacts from the modification of natural spaces, and decreased access to medical resources due to biodiversity loss. Furthermore, ocean acidification hinders the ocean's ability to absorb CO2, exacerbating global warming and climate change.

To address ocean acidification, implementing solutions to reduce the use of fossil fuels and mitigate climate change is crucial. By acting now, we can significantly reduce the harm to marine ecosystems and maintain the vital services provided by the ocean that contribute to human health and well-being.

Eutrophication

Ocean acidification has significant ecological implications. It slows the growth of fish and shellfish and can even prevent shell formation in bivalve mollusks. This, in turn, leads to reduced catches for commercial and recreational fisheries, resulting in smaller harvests and increased seafood prices. Eutrophication also contributes to the creation of "dead zones" and fish kills, further disrupting marine ecosystems.

The process of eutrophication is accelerated by air pollution, particularly the presence of certain pollutants such as nitrogen, ammonia, and mercury. These pollutants can enter water bodies through atmospheric deposition, where they fall from the air as dust or are washed into waterways by rain. Once in the water, these pollutants act as nutrients that fuel the growth of algae and plants, initiating the eutrophication process.

Ammonia (NH3) emissions, for example, are four times higher than pre-industrial levels due to agricultural activities and livestock manure. This reactive pollutant contributes to eutrophication and acidification. Similarly, nitrogen fertilizers used in agriculture can end up in water bodies, acting as a nutrient source for algae and contributing to eutrophication.

Addressing air pollution is crucial to mitigating eutrophication and its associated ecological consequences. While the complex interactions between air and ocean pollution are still being unravelled, it is evident that the two are intricately linked. Thus, efforts to reduce atmospheric deposition of pollutants and improve air quality can play a significant role in preserving marine ecosystems and maintaining the health of our oceans.

Mercury and methylmercury pollution

Mercury is a naturally occurring element in the Earth's crust. However, human activities such as mining, fossil fuel combustion, electricity production, and waste incineration have led to widespread global mercury pollution. Mercury emitted into the air eventually settles into water or onto land, where it can be washed into water bodies. Once deposited, certain microorganisms can convert it into methylmercury, a highly toxic form that builds up in fish, shellfish, and animals that eat fish.

Methylmercury is a neurotoxin that can cause severe health issues, especially in children exposed in utero and women of childbearing age. The US Environmental Protection Agency (EPA) has issued warnings against consuming certain types of fish, such as shark, swordfish, king mackerel, and tilefish, due to their high methylmercury levels. In 2003, the EPA also reported that advisories against consuming fish due to mercury contamination were issued for 44 states and American Samoa, with warnings for nearly one in four rivers and one in three lakes in the US.

The impact of mercury and methylmercury pollution in the marine environment has been a significant concern since the Minamata Bay poisoning incident in the 1960s. The high levels of atmospheric mercury influence ocean surface water, and the contamination level is affected by surrounding emission sources such as industrial and petroleum activities. This, in turn, increases mercury levels in fish species, posing adverse risks to human health through biomagnification.

The NYS Department of Health (DOH) recommends that people limit their consumption of fish from certain waters, including the Hudson River and its marine waters, to just one meal (half a pound) per week. Children and women of childbearing age are advised to refrain from eating any fish from contaminated fresh or coastal waters in New York State.

Reducing mercury emissions is crucial for mitigating its impact on both the environment and human health. Mercury's ability to circulate in the atmosphere and undergo chemical transformations makes it a persistent global pollutant. Human activities play a significant role in its release into the environment, and regulatory measures are necessary to minimize its harmful effects.

Persistent organic pollutants

POPs are mostly man-made and include pesticides, insecticides, solvents, pharmaceuticals, and industrial chemicals. Chlordane, for instance, is an insecticide lethal to several bird species and is believed to impact the human immune system. Dieldrin, another pesticide, is highly toxic to fish and other aquatic life, causing spinal deformities in frog embryos even at low exposure levels.

The Clean Air Act regulates hazardous air pollutants, including dioxins and furans, which are also classified as POPs. The United States, along with 90 other countries and the European Community, signed the Stockholm Convention in 2001 to address POPs. This treaty aims to reduce or eliminate the production and release of 12 key POPs, recognizing their potential for long-range transport, bioaccumulation, and adverse health effects such as cancer and diminished intelligence.

The Global Environment Facility (GEF) has committed significant funds to POPs projects, supporting the disposal of PCBs, obsolete pesticides like DDT, and the reduction of unintentionally generated POPs. The Basel Convention, another legally binding instrument supported by GEF programming, addresses the transboundary movement and disposal of hazardous wastes, including POPs. These efforts reflect a global recognition of the toxic effects of POPs on human health, wildlife, and the environment.

In conclusion, persistent organic pollutants (POPs) are toxic chemicals that pose a significant threat to human health and the environment. Their resistance to degradation, long-range transport, and bioaccumulation properties have led to worldwide concerns. International efforts, such as the Stockholm Convention and GEF initiatives, aim to reduce and eliminate POPs to safeguard human well-being, wildlife, and the environment from their devastating impacts.

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