The Health Hazards of Mercury


Feature Story

If you’re fond of deep-sea fish and sea foods, you may have to think twice as increasing levels of mercury contaminate the seas, and endanger people’s lives

By Henrylito D. Tacio


“If there’s Walking Dead Part 8, it might be here in Sta. Lourdes,” Gerry Valena, a longtime resident of the area, admitted to Redempto D. Anda, a correspondent of Philippine Daily Inquirer. He likened his barangay to the setting of the popular zombie television series as homes and farms are deserted.

Sta. Lourdes along with Tagburos, both located near the Honda wharf in Puerto Princesa, Palawan, are “slowly being poisoned with mercury even after mining operations there stopped more than 30 years ago,” according a recent study conducted by the Department of Health (DOH).

“A random testing conducted by the DOH on 104 residents yielded positive results for mercury in their blood and hair samples, and noted symptoms of contamination in neurological and physical assessments,” the news report said.

The city government and national government have been asked “for help to undertake a comprehensive medical treatment for residents,” according to Valena who heads the barangay council’s environment committee. Medical treatment costs from as low as PhP 30,000 to as high as PhP 200,000 per patient.

Although the roughly 10,000 residents are advised to leave the homes, not most of them are willing to do so. “Many remain unperturbed by the magnitude of the problem, already described by authorities as ‘reaching crisis proportions,’” the news report said.

The mercury contamination reportedly came a mine pit that was abandoned by the now-defunct Palawan Quicksilver Mine, Inc. “This contaminated pit ran down to the Tagburos River, which flows into ecotourism destination Honda Bay in Barangay Tagburos,” another news report said.

“Consumption of fish harvested from contaminated water bodies was blamed for mercury poisoning cases. Traces of mercury were also found in fish and shellfish around the wharf area in Santa Lourdes,” it added.

The recent event is not the first occurrence in the Philippines. There were several other mercury contamination that happened in the past since mining is one of the biggest industries in the country. It must be recalled that in 1987 the Philippines was the toast of the news around the world when mercury poisoning was reported in Tagum, then a booming town of Davao del Norte.

Mark Fineman, then a staff writer of the Los Angeles Times, made a thorough special report starting with the death of Aquim, the son of Antonio Torino from acute mercury poisoning. “The first in what health authorities say could be a toll of hundreds, or even thousands, in the next few years unless the government takes drastic action now,” he penned.

In his report, dated May 31, 1987, Fineman wrote: “The seeds of Tagum’s environmental disaster were sown more than three years ago, when this remote town near the southern coast of the southernmost large island of Mindanao became the hub of Asia’s biggest gold rush.

“Prospectors had discovered a gold vein in Tagum’s province of Davao del Norte rivaling that of the richest regions of South Africa, a mother lode so rich that tens of thousands of peasants-turned-prospectors flocked here from throughout the nation. In the last 16 months alone, those once impoverished farmers have cashed in more than $281 million worth of gold. Tagum was transformed from a rural basket case into a Mecca of opportunity.

But Tagum had a price to pay for the boom. “The gold rush spawned hundreds of unlicensed, small-time refineries, most of them in the heart of the town. All of them use liquid mercury as part of a crude method for drawing the gold from the ore,” Fineman wrote.

“The ore is first mixed with water in a giant tumbling machine, called a ball mill. The tumbling action pulverizes the ore. The refiner then places some of the ore-and-water mixture in a shallow wooden pan and adds the liquid mercury. As the refiner kneads and massages the mixture, the mercury and gold form into a malleable lump.

“To separate the gold from the mercury, the amalgam is burned with crude blowtorches, vaporizing most of the mercury into the air. The liquid waste in the pan, which includes leftover mercury, is dumped into the canals leading to the rivers that provide the island’s drinking water and food for the fish that the island’s residents eat.”

Mercury poisoning is almost always associated with Minamata disease. It is named after a port city in southeastern Kyushu in Japan. It was first reported in 1953 when 13 persons were suffering from what was then a strange malady.

A historical narrative for Michiko Ishimure, who won the 1973 Ramon Magsaysay Award for publicizing writings about the Minamata disease, shared this information: “(The strange malady) usually manifested itself first in numbness and a ‘drunken’ loss of coordination, which progressively led to a total loss of the ability to walk, speak, write, see, hear, smell and feel. In its later stages, it resulted in severe deformation of the body, convulsions, fantastic behavior and death.”

Minamata disease
Minamata disease

By 1956, some 52 persons were known sufferers and by 1958, the Minamata City Hospital had to add a wing to accommodate the patients. It was not until in July 1959 that Japanese medical experts identified mercury as the cause of what became officially known as Minamata Disease.

In 1965, Minamata disease was again reported in Niigata, on the East Coast of Honshu. Again, scientists made public their definite conclusion: the disease was from mercury emptied into the river.

Meanwhile, a new study published in the journal, Science Advances, showed that rising temperatures – caused by global warming – could boost mercury levels in fish by up to seven times the current rates.

“(The researchers) have discovered a new in which warming increases levels of the toxin in sea creatures,” wrote Matt McGrath, environment correspondent for BBC News. “In experiments, they found that extra rainfall up the amount of organic material flowing into the seas. This alters the food chain, adding another layer of complex organisms which boost the concentration of mercury up the line.”

McGrath further wrote: “In a large laboratory, Swedish researchers recreated the conditions found in the Bothnian sea sanctuary. They discovered that as temperatures increase, there is an increased run-off of organic matter into the world’s oceans and lakes. This encourages the growth of bacteria at the expense of phytoplankton.”

Dr. Erik Bjorn from the Umea University in Sweden was quoted as saying: “When bacteria become abundant in the water, there is also a growth of a new type of predators that feed on bacteria. You basically get one extra step in the food chain and methylmercury is enriched by about a factor of ten in each such step in the food web.”

Mercury, a naturally occurring element in the Earth’s crust, is one of the world’s most toxic metals. It is released into the atmosphere with natural events such as volcanic activity. The Geneva-based World Health Organization (WHO) considered mercury as “one of the top ten threats to public health.”

Actually, there are two types of mercury: inorganic and organic. Metallic mercury, which is a type of inorganic mercury, is used in familiar items such as fluorescent lights, batteries, and thermometers. The methyl mercury is a type of organic mercury. It is a white powdery substance and smells like the sulfur in a hot spring. It is easily absorbed from the stomach into the blood and carried to the liver and kidney, and then the brain and even the fetus, where it is absorbed and concentrated and causes great damage to the human body.

“Human activities like coal burning, gold mining and chloralkali manufacturing plants currently contribute the vast majority of the mercury released into our environment,” explained Dr. Anne M. Davis, an assistant professor of nutrition and dietetics director at the Didactic Program in Dietetics of the University of New Haven.

In an article which Live Science published, author Alina Bradford wrote: “When mercury is released into the atmosphere, it dissolves in fresh water and seawater. A type of mercury called methylmercury is most easily accumulated in the body and is particularly dangerous.”

A paper published by the Journal of Preventive Medicine and Public Health said that about 80 percent-90 percent of organic mercury in a human body comes from eating fish and shellfish, and 75 percent-90 percent of organic mercury existing in fish and shellfish is methylmercury.

The US National Institutes of Health said that mercury poisoning is a slow process that can take months of years. Since the process is so slow, most people don’t realize they are being poisoned right away.

“The populations most vulnerable to mercury are pregnant women (because it affects fetuses) and small children,” wrote Linda Greer, Michael Bender, Peter Maxson, and David Lennett, authors of Curtailing Mercury’s Global Reach, one of the reports included in the “State of The World” published by Worldwatch Institute.

“A child’s brain develops throughout the first several years of life, and mercury interferes with development of the neuron connections in the brain crucial to a healthy nervous system. High levels of prenatal and infant mercury exposure can cause mental retardation, cerebral palsy, deafness, or blindness,” the four authors noted.

The Health  Hazards of Mercury
Methylmercury can be acquired from eating contaminated marine products

Even in much lower doses, mercury exposure is still dangerous. “(It) may affect a child’s development, leading to such results as poor performance on neurobehavioral tests, particularly those relying on attention, fine motor function, language, visual spatial abilities (such as drawing), and verbal memory,” the four authors pointed out.

In adults, chronic mercury poisoning can cause memory loss, tremors, vision loss, and numbness of the fingers and toes and can adversely affect fertility and blood pressure regulation. There’s also a growing body of evidence that suggests that exposure to mercury may also contribute to heart disease in adults.

Humans have had a long history with mercury, and it is well known, for instance, that mercury was used in the gold plating of the Great Buddha in Nara, and in the Edo period in medicine and facial powder. Furthermore, Japanese place names such as Niu indicate areas where mercury was produced and used long ago.

Mercury has long been known to be toxic; the phrase “mad as a hatter” refers to the 19th-century occupational disease that resulted from prolonged contact with the mercury used in the manufacture of felt hats. Some workers today, especially laboratory technicians, nurses, and machine operators, continue to be exposed to mercury on the job.

In the United States, most mercury pesticides have been withdrawn from the market, and many countries banned ocean dumping of mercury and other pollutants in 1972. In 1991, production of mercury containing interior and exterior paints in the US was phased out.

But despite the banning of dumping of mercury in the oceans, levels of mercury in the global environment have risen sharply over the past two centuries due to man-made releases from industrial processes, products, mining, waste disposal, and coal combustion.

Although it travels through the atmosphere, it settles in oceans and waterways, where naturally occurring bacteria absorb it and convert it to methylmercury. Here’s what happened, according to Bradford:

“Once in the water, mercury makes its way into the food chain. Inorganic mercury and methylmercury are first consumed by phytoplankton, single-celled algae at the base of most aquatic food chains. Next, the phytoplankton are consumed by small animals such as zooplankton. The methylmercury is assimilated and retained by the animals as waste products. Small fish that eat the zooplankton are exposed to food-borne mercury that is predominantly in the methylated form. These fish are consumed by larger fish, and so on until it gets to humans.”

Predatory fish such as large tuna, swordfish, king mackerel, pike, walleye, barracuda, and marlin contain the highest methylmercury concentrations.

“As a result, this contaminant now endangers people on every continent, exceeding established safe levels in various fish and marine mammals and threatening the viability of wildlife populations as well, the Worldwatch authors wrote.

“Predatory fish such as large tuna, swordfish, king mackerel, pike, walleye, barracuda, and marlin contain the highest methylmercury concentrations”

July 2017 Health and Lifestyle

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