Cadmium (Cd) is a well-known global environmental pollutant. In Japan, however,
the problem of environmental pollution by Cd has appeared as severe cases of
human poisoning, known as itai-itai disease, which occurred in a confined local
area. The cause of itai-itai disease has been linked to the Cd-contaminated mine
wastewater leaked from the Kamioka zinc mine, which is located upstream of the
Jinzu River in Toyama Prefecture. On a worldwide scale, the severity of the symptoms
of itai-itai disease has created a sense of urgency, leading to a global recognition
of Cd as a serious environmental pollutant. Until now, however, the details of
the clinical, epidemiological, and pathological aspects of itai-itai disease have not
been sufficiently recognized even among the scientists involved in metal
toxicology.
As a volcanic country, Japan is blessed with many mining resources. Because
many mines and smelting factories had been operating in the mountainous areas in
the past, the water of the river, in addition to the Jinzu River, used for the irrigation
of paddy fields had been polluted by Cd. Although strict restriction and management
by the government during the last decades have improved the situation, the
paddy fields still contain low-level Cd in some areas. Since the rice is a staple food
among Japanese, the consumption of rice contributes significantly to total Cd intake
among Japanese compared with other countries. The National Institute of Health
Sciences has reported (2015) that rice is the major source of Cd consumption among
Japanese, accounting for about 30% (previously more than 40%) of the total Cd
consumption from diet (Chap. 1). Thus, the reduction of Cd in rice is still an important
issue in agricultural policy in Japan. In recent years, advances in soil sciences
and plant physiology have led to a number of successful countermeasures against
Cd accumulation in rice in Japan.
The contributors to this volume were chosen for their expertise on various aspects
of Cd toxicity in Japan. Thus the contents include not only medical and biochemical
considerations of Cd toxicity but also agricultural science investigations into the
mitigation of Cd accumulation in rice.
Part I (Overview; Chap. 1) provides a historical overview of itai-itai disease,
including the social aspects, and discusses the roles of regulatory science in