Minamata Bay

Front 1

When methylmercury is present in the aquatic system, organisms absorb the toxin, which then accumulates in their fatty tissues.
Bioaccumulation then occurs as an animal eats another and stores in inside of its fat.
Once accumulated in mammals, the dose tends to be so high that the methylmercury begins to attack and deteriorate the brain, liver, and kidney which
In water, mercury has a half life of approximately 200 days, but once ingested this time is augmented to over nine months

Back 1

The cats in the local area, who tended to eat scraps from the family table, had died with symptoms similar to those now discovered in humans. This led the researchers to believe that the outbreak was caused by some kind of food poisoning, with contaminated fish and shellfish being the prime suspects.

Front 2

Once inside the body, its only means of leaving the body are by excretion through feces, breast milk, and urination.
****BIOACCUM: Mercury dumped into the bay, mercury attach to the bacteria, plankton eat bacteria, small fish eat plankton, big fish eat small fish, fishermen catch big fish, families eat big fish
They found that the victims, often members of the same family, were clustered in fishing hamlets along the shore of Minamata Bay. The staple food of victims was invariably fish and shellfish from Minamata Bay.

Back 2

Accumulates in the fatty tissues.
animal eats another organism
High dose attacks the body
Half life increases in the body
Mercury-plankton-fish- humans
Affects members of fisherman families

Front 3

The mercury levels in fish and shell fish varied from the levels of mercury in the cats as well as the humans due to the bioaccumilation and the amount of fish eaten.

Back 3

The concentration of mercury increases the further through the food chain it goes

Front 4

AFTERMATH:
Chisso stopped poisoning the water because method became outdated.
2 kg of mercury per ton of sediment
High enough to mine
Chisso collected the mercury from the sludge to sell

Back 4

When chisso stopped poisoning the water it was only because that method became outdated.
At the mouth of the wastewater canal a figure of 2 kg of mercury per ton of sediment was measured, a level high enough to be economically viable to mine.
Ironically, Chisso did later set up a subsidiary to reclaim and sell the mercury recovered from the sludge.
Hair samples were taken from the victims of the disease and also from the Minamata population in general. In patients, the maximum mercury level recorded was 705 parts per million (ppm), indicating very heavy exposure. In non-symptomatic Minamata residents, the level was 191 ppm compared to an average level of 4 ppm for people living outside the Minamata area.

Front 5

Non-symptomatic Minamata Residents were 191 ppm
Average in people outside of Minamata was 4 ppm
Maximum mercury level recorded was 705 ppm

Back 5

Compensation:
In 1996 the government gave the people who had claimed the disease $2,238 from Chisso and $179 a month for medical expenses. Problem is that thousands of people still trying to get diagnosed and helped.

2,265 victims have been officially certified (1,784 of whom have died) and over 10,000 people have received financial compensation from Chisso, although they are not recognized as official victims.

Front 6

Payments for deaths ranged from JPY1.7 million to JPY4 million (USD4,700 to USD11,100)
One-time payments from JPY1 million to JPY4.2 million (USD2,760 to USD11,660)
Annual payments of between JPY170,000 and JPY380,000 (USD470 to USD1,100) for surviving patients.

Back 6

Restoration:
1974- placed 3 mile long net to contain contaminated fish
1997- start of 359 million dollar project of vacuuming up 1.5 million cubic meters of mercury-contaminated sludge
1998- bay declared safe after 58 years

Front 7

· In order to help restore the bay, in 1974 a three-mile long net was placed around the bay to contain the contaminated fish.

Back 7

· In 1977 the Japanese government began the 359 million dollar project of vacuuming up 1.5 million cubic meters of the mercury-contaminated sludge. This was completed in 1997
· After 58 years of being considered deadly water, the bay was finally declared safe again in 1998