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6.2.9 Is the Mechanism of Minamata Disease (Methylmercury
Poisoning) Fully Understood and are the Victims
Properly for Damages? (Medical Framing and Its Social
Implications)
Another way of framing is whether the entire mechanism of the disease was sufficiently understood from a medical point of view. Even though the substance causing
the disease is has been clearly identified, the extent and condition of health damage
of the methylmercury varies significantly according to the amount of exposure to
methylmercury. However, as explained in the previous section, even today the relationship between the degree of exposure and the effect is not fully understood,
except the cases of high dosages with acute and lethal effects. This is partly caused
by insufficient data. Although mercury concentrations in hair and umbilical cords
were used for estimating the level of methylmercury, collecting data from those
whose symptoms were relatively milder was difficult. This is not only because such
mild-symptom sufferers hesitated to at taking health examinations, but also because
they had no inkling that they might have been affected by methylmercury in the first
place. It has been pointed out that the certification criteria of Minamata disease
victims tend to be limited to serious patients because this judgment resulted from
political and administrative issues related compensation certification criteria. For
this reason, scientific elucidation of how much damage has been caused by methylmercury poisoning became more problematic, and the total number of victims who
suffered health damage by methylmercury, including those with relatively mild
damage, remains elusive. Thus, a large-scale health investigation regarding the
effects of methylmercury is has been carried out recently, accumulating more
knowledge about the overall picture of mercury-derived health damage, and trying
to “discover” people who suffered health damage by methylmercury, but who have
neither come forward nor have become aware of personal damage.
However, compared to severe methylmercury poisoning symptoms found in the
1950s and 60s, the health damage found in today’s health examinations is milder in
comparison, and situation surrounding such health examinations differs greatly
from those when the serious Minamata disease patients were discriminated against
and persecuted in the early years in the 1960s and 1970s. In addition, when considering milder health damage (for example, numbness of hands), it becomes more
difficult to distinguish such milder health damage from other health problems such
as diabetes caused by non-methylmercury factors, which can also cause numbness
in the hands, and becomes even more difficult to distinguish the impact from methylmercury derived from Chisso-polluted waters and other sources. Accumulating
scientific knowledge is indispensable. It is also necessary to draw a line of administrative guidance on how far to compensate. It is important to “settle” at a certain
M. Onuki
6.2.9 Is the Mechanism of Minamata Disease (Methylmercury
Poisoning) Fully Understood and are the Victims
Properly for Damages? (Medical Framing and Its Social
Implications)
Another way of framing is whether the entire mechanism of the disease was sufficiently understood from a medical point of view. Even though the substance causing
the disease is has been clearly identified, the extent and condition of health damage
of the methylmercury varies significantly according to the amount of exposure to
methylmercury. However, as explained in the previous section, even today the relationship between the degree of exposure and the effect is not fully understood,
except the cases of high dosages with acute and lethal effects. This is partly caused
by insufficient data. Although mercury concentrations in hair and umbilical cords
were used for estimating the level of methylmercury, collecting data from those
whose symptoms were relatively milder was difficult. This is not only because such
mild-symptom sufferers hesitated to at taking health examinations, but also because
they had no inkling that they might have been affected by methylmercury in the first
place. It has been pointed out that the certification criteria of Minamata disease
victims tend to be limited to serious patients because this judgment resulted from
political and administrative issues related compensation certification criteria. For
this reason, scientific elucidation of how much damage has been caused by methylmercury poisoning became more problematic, and the total number of victims who
suffered health damage by methylmercury, including those with relatively mild
damage, remains elusive. Thus, a large-scale health investigation regarding the
effects of methylmercury is has been carried out recently, accumulating more
knowledge about the overall picture of mercury-derived health damage, and trying
to “discover” people who suffered health damage by methylmercury, but who have
neither come forward nor have become aware of personal damage.
However, compared to severe methylmercury poisoning symptoms found in the
1950s and 60s, the health damage found in today’s health examinations is milder in
comparison, and situation surrounding such health examinations differs greatly
from those when the serious Minamata disease patients were discriminated against
and persecuted in the early years in the 1960s and 1970s. In addition, when considering milder health damage (for example, numbness of hands), it becomes more
difficult to distinguish such milder health damage from other health problems such
as diabetes caused by non-methylmercury factors, which can also cause numbness
in the hands, and becomes even more difficult to distinguish the impact from methylmercury derived from Chisso-polluted waters and other sources. Accumulating
scientific knowledge is indispensable. It is also necessary to draw a line of administrative guidance on how far to compensate. It is important to “settle” at a certain
M. Onuki