Ocean Pollution Notes

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.