Heavy Metal Pollution in Japan Soil: Itai-Itai Disease

My previous blog posts discussed about Fukushima nuclear disaster that happened recently. In this post, we shall travel back in time, to the 1950s. Back then Japan was experiencing one of the Big 4 pollution diseases (Itai-Itai disease, Minamata disease, Niigata Minamata disease and Yokkaichi Asthma). Itai-itai disease is chosen as it resulted from heavy metal pollution in soils, which is land pollution too.

Background

Rapid industrialization in the 1950s resulted in heavy metal pollution in soils. At Toyama prefecture, a Kamioka mine was producing zinc and lead at the upper stream of Jinzu River basin (refer to Image 1). It was one of the largest zinc and lead mines before World War II (Mansori, 2012). During the war, increased demand for these metals resulted in a relaxation of normal procedures used to prevent river contamination (The Lancet, 1971). Consequently, large amounts of cadmium were loaded into the upper stream of Jinzu River where the mine was located. Since Cadmium was a byproduct of the mining and it had little industrial value at that time, no efforts to recover cadmium were done (Mansori, 2012). Jinzu River thus became heavily polluted with cadmium. People along the riverbank consumed the polluted water for drinking and used it for irrigation. Water pollution became soil pollution. Heavy metal, cadmium, retained in the soil and subsequently got uptake by plants. Crop that was most severely damaged was rice, as metals, especially cadmium, tend to accumulate in rice roots (The Lancet, 1971). Residents near Jinzu River suffered most from itai-itai disease, and it took experts years later to confirm the correlation between the disease and its source.

Image 1: Map of Toyama Prefecture and the Varying Severity of Cadmium Pollution (Source: Kanazawa Medical University, n.d.)

Impact

Since the year 1967 till 2011, 196 people have been diagnosed with itai-itai disease and only 4 victims survive today (Toyama Prefectural Itai-Itai Disease Museum, n.d.). Another 336 people in Toyama prefecture are under clinical observation. Pregnant and elderly woman are most susceptible to chronic cadmium poisoning. Pregnant ladies tend to increase their food intake to increase zinc uptake. A normal lady requires 7mg of zinc per day but ladies during pregnancy and lactation requires up to 13mg of zinc per day (Rasnake, 2009). In Toyama, pregnant woman inevitably consume more rice, as it is a staple food in their diet. Since the rice crops were irrigated with cadmium polluted river water, rice that was eaten is saturated with cadmium and depleted of zinc (ibid.). Instead of getting more zinc, pregnant women are loading more cadmium. When the body is zinc deficient, the retention rate of cadmium increases 15 fold (ibid.). This is similar for elderly people as nutrient deficiency makes them more prone to itai-itai disease. Prevalence of itai-itai disease is still prevalent in women over 50 years of age today (WHO, 2010). Prevalence rate is highest around the banks of Jinzu river where the mine was located (refer to Image 2).

Image 2: Prevalence Rate of Itai-Itai Disease in Toyama Perfecture (Source: Kanazawa Medical University, n.d.)

Symptoms

Victims of itai-itai disease are highly handicapped and suffer from chronic bone pains. When significant amount of cadmium accumulates in the body, irreversible damage to the kidneys and liver results. Kidneys loses its ability to remove acid from the blood and this is known as Proximal Renal Tubular Dysfunction (Rasnake, 2009). In addition, softening of the bones (Osteomalacia) and weakening of bone mass (Oseteoporosis) happens with cadmium poisoning (refer to Diagram 1). 

Diagram 1: Symptom of Chronic Cadmium Poisoning (Itai-itai disease) in patients (Source: Toyama Prefectural Itai-itai Disease Museum, n.d.)

Eventually, patients can suffer bone fractures and are confined to the bed with full body aches. Sufferers tend to shout ‘Ouch-ouch’ and this is how the name ‘Itai-itai’ was originated. To give you a better understanding of the disease, I would like to share with you this video (from 4:20 onwards).

It can be seen that itai-itai disease is highly debilitating and often results in slow death. Cadmium poisoning is thus a serious public health concern. Even at low doses, cadmium is highly toxic and can cause flu-like symptoms that are known as Cadmium Blues. According to the World Health Organization (WHO), the provisional tolerable monthly intake of cadmium is 25 microgram per kg of body weight (WHO, 2010). The threshold in drinking water was set at 3 microgram per litre. When cadmium is ingested in excess, it is accumulated in the body and has a half-life of 20 to 35 years (ibid.). Therefore, medical observations of suspected cases in Toyama are still ongoing today and the number of itai-itai patients might increase further.

Remediation Efforts

Victims of itai-itai disease filed against Mistui Mining & Smelting Co., Ltd (owner of Kamioka mine) in 1968 to seek compensation (Mansori, 2012). Two important victories came into force. Firstly, the company will compensate all sufferers and those under medical observation. Secondly, a Pollution Control Agreement was drafted to allow itai-itai victims group, known as the Itai-itai Disease Residents Association, to enter and inspect the mine anytime, with the companion of experts (ibid.). According to contract terms, Mitsui Co. is obliged to negotiate with the Residents Association and do its best to prevent further pollution. Since then, there was a 30-year continuous inspection and random water samplings for cadmium concentration. Cadmium pollution reduced greatly and the mean concentration of cadmium (background level) reached 0.1ppb (parts per billion) in 1966. Pressure from citizens and experts also got the government and company restore the polluted soil. This case has thus demonstrated the collaborative efforts of various stakeholders in addressing an environmental pollution effectively, and which was a great success.

Conclusion

Outbreak of Itai-itai disease was first observed in Toyama Prefecture, Japan, and victims are still suffering the health impacts today. From mining to water pollution and subsequently soil pollution, heavy metals such as cadmium can be highly mobile in the environment. Thus, environmental pollution should not be taken lightly as it can become a public health problem anytime. This has been reflected in the case of Itai-itai disease and it is indeed possible to stop pollution if only all stakeholders are actively involved in the solution-making process.

References

Kanazawa Medical University. (n.d.). Kanazawa-med.ac.jp,. 'Itai-Itai Disease'. Web.

Masanori, K. A. J. I. (2012). Expert and Citizen Participation in the Pollution Control: The Case of Itai-itai Disease in Japan.

The Lancet. 'Cadmium Pollution And Itai-Itai Disease'. The Lancet 297.7695 (1971): 382-383. Web. Retrieved from http://ac.els-cdn.com/S0140673671922161/1-s2.0-S0140673671922161-main.pdf?_tid=f15f1c14-db67-11e4-9548-00000aab0f6b&acdnat=1428220200_4721dfd531394bd1712c0a676a7cbdc1

Makino, T. (2007). Heavy metal pollution of soil and a new approach to its remediation: research experiences in Japan. Food and Fertilizer Technology Center.

World Health Organization, (2010). Exposure to Cadmium: A Major Public Health Concern. N.p.,Web. Retrieved from http://www.who.int/ipcs/features/cadmium.pdf

Rasnake, Jarrod. (2009). 'Metals In Medicine And The Environment'. Faculty.virginia.edu. Web. Retrieved from http://faculty.virginia.edu/metals/cases/rasnake1.html

Toyama Prefectural Itai-itai Disease Museum, (n.d.). About the Itai-itai Disease. Web. Retrieved from http://itaiitai-dis.jp/lang/english/disease/02.html