Ocean Pollution: Global Problems Require Global Solutions
Introduction
Approximately 18 billion tons of plastic enter the world's oceans annually, equating to just over 49 million pounds every single day.
Plastic is the most plentiful source of marine debris and pollution, receiving the most attention from media and advocacy groups.
However, plastic isn't the only source; oil spills, mercury, manufactured chemicals (e.g., pesticides), and nutrients (e.g., fertilizers) also pose significant problems.
The Ocean Pollution Iceberg (Fig. 1)
Ocean pollution is widespread, worsening, and poorly controlled in most countries.
Human activities result in a complex mixture of substances entering the aquatic environment.
More than 80% of ocean pollution arises from land-based sources, reaching the oceans through rivers, runoff, atmospheric deposition, and direct discharges.
Ocean pollution has multiple negative impacts on ecosystems and human health, particularly in vulnerable populations.
Plastic Waste
Plastic is a rapidly increasing and highly visible component of ocean pollution. An estimated 10 million metric tons enter the seas each year.
Plastic pollution threatens marine mammals, fish, and seabirds.
It breaks down into microplastic and nanoplastic particles containing multiple manufactured chemicals that can enter marine organisms, including species consumed by humans.
Oil Spills
Oil spills have occurred with increasing frequency due to growing global demand for petroleum.
These spills result in the direct release of millions of tons of crude oil and other petroleum products into the oceans.
Petroleum-based pollutants reduce photosynthesis in marine microorganisms that generate oxygen.
They also disrupt food sources, destroy fragile habitats such as estuaries and coral reefs, and foul beaches.
Manufactured Chemicals
Manufactured chemicals like phthalates, bisphenol A, flame retardants, perfluorinated chemicals, and pharmaceutical waste can disrupt endocrine signaling.
These chemicals can reduce male fertility, damage the nervous system, and increase the risk of cancer.
They can also damage coral reefs.
Mercury
Mercury is released from two main sources: coal combustion and small-scale gold mining.
Exposure of infants in utero (when pregnant mothers eat contaminated seafood) can cause IQ loss and serious developmental disorders.
In adults, mercury increases risks for dementia and cardiovascular disease.
Pesticides
Pesticides are specifically designed to have biological effects, and thus even low-dose exposures can affect living organisms, including humans.
Pesticides contribute to global declines in fish stocks and can also reduce human fertility.
Nutrients
Industrial releases, runoff from animal feedlots, and human sewage increase the frequency and severity of harmful algal blooms (HABS), bacterial pollution, and anti-microbial resistance.
The Way Forward
World leaders must take bold, evidence-based action to stop pollution at the source to prevent ocean pollution and safeguard human health.
Measures to consider:
Better management of plastic waste
Bans on single-use plastics
Chemical control policies
Mandatory premarket toxicity testing
Wide-scale transition to renewable fuels
Banning mercury use
Eliminating coal combustion
Transition to a circular economy
Embracing green chemistry
Bans on persistent organic pollutants (POPS)
Control of industrial discharges
Better treatment of sewage
Reduced applications of fertilizers
Building scientific capacity
Designation of Marine Protected Areas (MPAs)
Societal Awareness and Effects on Us
Whether there is an actual increase in the disposal of pollutants into oceans, or we are simply becoming more aware of the issue through media coverage, the world has a pressing environmental problem to deal with.
The overarching problem of ocean pollution can be simplified by analyzing the various issues that contribute to the whole.
Some of the smaller problems that add up to this larger, global problem are:
Damage to marine ecosystems
Contamination of food sources
Creation of large garbage patches of trash
Much of the recent research in marine sciences has focused on these problems, making society well aware and fairly informed about them.
However, society is largely unaware of the effects ocean pollution has on us.