Marine Pollution: Killing Our Whales

By December 2, 2011 December 5th, 2011 Ocean Solutions
Marine Pollutant DDT

Water pollution…are you familiar with it? Did you know that out of all the major Ocean issues, water pollution is not talked about much.

As a researcher in the marine mammal field, I’ve noticed several public perceptions that seem to persist throughout each city I visit and each demographic I talk to. Generally, people are really concerned about the dolphins in Taiji. People are also really upset about whaling. Sometimes people even share worries about unsustainable ecotourism. However, I’m almost never get asked questions about water pollution in the Oceans. This is especially alarming, because water pollution in the Oceans represents one of the biggest threats to marine mammals (whales, dolphins, and seals) around the world.

It is a complicated issue with multiple sources and many detrimental effects–most of which are not actually fully understood. This post is the first of a 3 part series where the issue will be broken down into the following sections: (1) Sources and Contaminants, (2) Ecology of apex predators like dolphins, and (3) What we can do to help. This post covers the 1st of the 3 parts: Sources and Contaminants.

There are many kinds of pollutants found in the marine environment globally, which include chemical compounds, oil-pollution derived substances, marine debris (including plastic), sewage-related pathogens, excessive amounts of nutrients that change the environment, and radionuclides. Most of the research published, however, represents work performed on chemical compounds such as organochlorines and heavy metals.

Marine Pollutant DDT

A farmworker in Malaysia spraying DDT on crops, which is a very toxic substance that often ends up in the Ocean and can harm whales, dolphins, and seals.

Organochlorines are used for a variety of industrial and agricultural purposes. The two most well-known are DDT and PCBs. DDT is an agricultural pesticide, while PCBs are used for a huge array of purposes, including inks, plastics, electrical transformers, and many others. These compounds are so toxic that they were both banned from use by the 1980s due to their apparent toxic effects. The ban, however, was only enforced in developed countries and even to this day these chemicals are still being used in third world countries.

Organochlorines severely damage vital organs including the brain and liver and also have a sterilizing effect on males. The effect of organochlorines on females and young is a bit more complicated and will be discussed more in the next post.

The three most common heavy metals in the scientific literature are lead, mercury, and cadmium. All of these elements do occur naturally in the environment at trace levels (i.e. small levels), but due to a variety of man-made industrial processes, levels in the environment are now much higher than they have ever been. The toxic effects of metals are varied but they, too, damage the vital organs like the brain, liver, kidney, blood, and bones.

In the next post I will discuss the effects of these pollutants in the marine environment, specifically on cetaceans and their survival in the wild. I will also discuss some interesting adaptations that some species have demonstrated to help them cope with surprisingly high levels of pollutants in their environment.

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  • […] I've noticed several public perceptions that seem to persist … … See more here: Marine Pollution: Killing Our Whales | Speak Up For The Blue ← EPA Finds Compound Used in Fracking in Wyoming Aquifer […]

  • Hi,

    I just wanted to let you know that plastic debris disposed at sea by commercial and recreational fisheries is tolerated by the National Marine Fisheries Service. Fisheries Observers in the Southeast region of the US report everything being thrown overboard, including all light sticks used to fish for swordfish, tangled up monofilament line and daily trash – cups, plates, etc. Observers are told by their trainers “..if you have a problem with plastics going overboard, you better get out of the program now.” They’re told these violations aren’t of concern to the NMFS. Reporting fisheries violations is a component of most observer programs but those in the Southeast ignore them. Please see our letter to the NOAA Inspector General:

  • Association for Professional Observers and Public Employees for Environmental Responsibility (PEER) wrote a letter to NOAA’s Inspector General requesting an investigation into the practices of the Observer Programs managed by the Southeast Region of NMFS. The request for investigation is based on a statement by a Southeast Fisheries Observer in the Pelagic Observer Program, as well as comments made by other Observers anonymously. The allegations accuse NMFS of ignoring witnessed fisheries violations and failure to enforce laws that support the safety and welfare of Fisheries Observers. See our letter at:

  • […] Marine Pollution: the Problem of Bioaccumulation I continue my 3-part series on water pollution in the Ocean environment. Last week I introduced the types of toxins found in the marine environment from marine pollution and mentioned a few of the phy…. […]

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