Coastal Marine Environment Sustainability - Sustainable Practices in Geoenvironmental Engineering - page 285

100

Estimated B G

80

60

40

20

Cu = 20 mg/kg

0

0 20 40 60 80 100

Fines content (%)

FIGURE 8.12
Deviation of copper (Cu) concentration in various sediments.

As stated in the previous section and shown in Table 8.3, there is a risk that the intake of
hazardous substances beyond the PEL values may be harmful to human health.

8.4.5.2 Minamata Disease

In the 1950s, a signiicant number of people succumbed to a disease, later identiied as
Minamata disease, that was traced to ingestion of poisoned ish and shellish in Minamata
Bay in Kyushu Island (Japan). Measurements of methylmercury chloride showed very
high concentrations, up to approximately 50 ppm in ish and 85 ppm in shellish from
the contaminated areas in Minamata Bay. The more than 100 people that ingested the
contaminated ish and shellish showed initial symptoms of numbness of the limbs and
areas around the mouth, sensory disturbance, lack of coordination, weakness and tremor,
speech, and audiovisual dificulties. Progressive worsening of all of these with time led
to general paralysis, convulsions, brain damage, and death. Traces of mercury poisoning
were also found in animals living around the bay. Many of these animals also died. More
details of this terrible demonstration of the impact of polluted sediments can be found
in http://www.env.go.jp/chemi/minamata.html (Ministry of Environment, Japan, 2014)
and http://unu.edu/publications/books/ilter/publisher=42&ref=/unupbooks/uu35je
/uu35ie0c.htm/ (United Nation University, 2014).
It is useful to note that although Minamata disease is well documented and serves as a
dramatic demonstration of the chain of effects originating from polluted sediments, dis-
covery and diagnosis of the health problems and source of the health problem took some
considerable time, effort, and tracking. There are undoubtedly countless cases of poisoned