Will we be Fishless?: Part V

A recent study has illustrated that even Mother Nature with her volcanoes (there are approximately 1,500 known, active volcanoes worldwide) is adding higher levels of mercury than she has to date. There are an unknown number of volcanoes on the ocean floor.

Mercury is a toxic, trace metal that bioaccumulates with a long atmospheric life cycle. Volcanic mercury exists as gas, as well as particulate matter. Volcanoes are the only natural sources of direct mercury emission into the troposphere and stratosphere, and are the principal natural sources of reactive and particulate mercury in the soil and water.

The researcher suggests that if you are living near volcanic ash you try and get a reading off a hair sample to be sure you have not absorbed the mercury internally.

We have been aware, through the news, of recent Mount Etna eruptions, producing amazing visuals. Scientist have measured 2 tons of mercury in the resultant gas production.

When this element makes its way into the ocean, it becomes highly reactive with organic matter and is readily taken up by phytoplankton, which mollusks then eat.

The WHO, in their fact sheet, say:

Key facts

  • Mercury is a naturally occurring element that is found in air, water and soil.
  • Exposure to mercury – even small amounts – may cause serious health problems, and is a threat to the development of the child in utero and early in life.
  • Mercury may have toxic effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes.
  • Mercury is considered by WHO as one of the top ten chemicals or groups of chemicals of major public health concern.
  • People are mainly exposed to methylmercury, an organic compound, when they eat fish and shellfish that contain the compound.
  • Methylmercury is very different to ethylmercury. Ethylmercury is used as a preservative in some vaccines and does not pose a health risk.

The WHO goes on to say:

Generally, two groups are more sensitive to the effects of mercury. Foetuses are most susceptible to developmental effects due to mercury. Methylmercury exposure in the womb can result from a mother’s consumption of fish and shellfish. It can adversely affect a baby’s growing brain and nervous system. The primary health effect of methylmercury is impaired neurological development. Therefore, cognitive thinking, memory, attention, language, and fine motor and visual spatial skills may be affected in children who were exposed to methylmercury as foetuses.

The second group is people who are regularly exposed (chronic exposure) to high levels of mercury (such as populations that rely on subsistence fishing or people who are occupationally exposed). Among selected subsistence fishing populations, between 1.5/1000 and 17/1000 children showed cognitive impairment (mild mental retardation) caused by the consumption of fish containing mercury. These included populations in Brazil, Canada, China, Columbia and Greenland.

A significant example of mercury exposure affecting public health occurred in Minamata, Japan, between 1932 and 1968, where a factory producing acetic acid discharged waste liquid into Minamata Bay. The discharge included high concentrations of methylmercury. The bay was rich in fish and shellfish, providing the main livelihood for local residents and fishermen from other areas.

For many years, no one realised that the fish were contaminated with mercury, and that it was causing a strange disease in the local community and in other districts. At least 50 000 people were affected to some extent and more than 2000 cases of Minamata disease were certified. Minamata disease peaked in the 1950s, with severe cases suffering brain damage, paralysis, incoherent speech and delirium.

Note: Acetic acid, systematically named ethanoic acid, is a colourless liquid organic compound with the chemical formula CH₃COOH. When undiluted, it is sometimes called glacial acetic acid. Vinegar is no less than 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water

Since coal naturally contains mercury, it is released when we burn it. But, according to an article in Forbes, 2015, we do not need to worry about how much mercury we release when burning it to generate electricity as it releases only small amounts of mercury–far less than natural sources of mercury such as volcanoeswildfires, dust and the oceans.

This article states:

Mercury, like any substance, is toxic in certain forms and doses and harmless in others. The form of mercury that is of particular concern to human health is called methylmercury (or monomethylmercury), a combination of mercury, carbon and hydrogen. Discussions of “mercury poisoning” are misleading, because mercury only becomes methylmercury under certain conditions, and methylmercury can only be absorbed by human beings in relevant quantities under certain conditions (for example, the element Selenium seems to prevent the absorption of methylmercury).

The main reason we are closing coal burning power stations and trying to reduce burning coal generally is, as most of us know, due to CO2 emissions;

 ………...prior to the Industrial Revolution, emissions were very low. Growth in emissions was still relatively slow until the mid-20th century. In 1950 the world emitted just over 5 billion tonnes of (CO2) – about the same as the US, or half of China’s annual emissions today.

By 1990 this had quadrupled to 22 billion tonnes. Emissions have continued to grow rapidly; we now emit over 36 billion tonnes each year.

Emissions growth has slowed over the last few years, but they have yet to reach their peak.

The risk of mercury poisoning (exampled in the Minamata instance) are described in this article:

They explain humans can consume too much mercury in foods. That is why we must limit our intake of fish now we know some fish contain more than others. Pregnant humans must be particularly careful. The food chain may also have higher mercury levels where toxic fish have become fishmeal for use in animal feeds. See

The analytical approach employed with Hydra-C is supported by EPA Method 7473 which is approved for both laboratory and field analysis for mercury in solids and liquids using Thermal Decomposition Amalgamation and Atomic Absorption Spectroscopy.
Typical applications of the Hydra-C Mercury Analyzer are:  Animal Tissues, Tobacco, Food byproducts, Marine Tissues and Vegetation.

……..Fish get mercury from the water they live in. All types of fish contain some amount of mercury. Larger types of fish can have higher amounts of mercury because they prey on other fish that have mercury too.

Sharks and swordfish are among the most common of these. Bigeye tuna, marlin, and king mackerel also contain high levels of mercury.

It’s also possible to develop mercury poisoning from eating too much seafood. In small amounts, the following types of fish are okay to eat once or twice per week:

  • albacore tuna
  • anchovies
  • catfish
  • grouper
  • pollock
  • salmon
  • shrimp
  • snapper

Though these options contain less mercury overall, you’ll want to take care in how much you eat.

What we eat, and how we eat, can be a major factor in determining everyday interactions such as with vinegar:

The “recycling” of anthropogenic mercury also raises levels of mercury in the environment. Recycling takes place when mercury in water volatizes and contributes to the increase of atmospheric mercury concentrations.

In 1995, it was estimated that forty percent (32 metric tons (t)) of mercury deposited form the air onto U.S. water and soil came from the global mercury reservoir. The other sixty percent came from anthropogenic sources in the U.S. There is uncertainty at this time as to how long some forms of mercury persist in the atmosphere.

In the past, mining was a substantial source of mercury in some areas. For example, the hydraulic placer-gold mines of the Sierra Nevadas released several thousand tons of mercury to the environment from the 1860s to the early 1900s. The U.S Geological Survey (USGS) believes that high levels of mercury in fish, amphibians, and invertebrates downstream of hydraulic mines are a result of historic mercury use.eu

Hydraulic placer-gold mining

This technique has poisoned fish in rivers ever since the Romans learned to apply it after seeing their conquered European tribes carrying it out. So humans have been causing mercury poisoning into rivers and seas ever since.

About borderslynn

Retired, living in the Scottish Borders after living most of my life in cities in England. I can now indulge my interest in all aspects of living close to nature in a wild landscape. I live on what was once the Iapetus Ocean which took millions of years to travel from the Southern Hemisphere to here in the Northern Hemisphere. That set me thinking and questioning and seeking answers. In 1998 I co-wrote Millennium Countdown (US)/ A Business Guide to the Year 2000 (UK) see https://www.abebooks.co.uk/products/isbn/9780749427917
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