Japan's tragic contamination reveals the destructive power of cadmium and sounds a critical warning about the disposal of old batteries and corporate electronic waste.
By the Environmental Investigation Team | Published in Technical Dossiers on Environmental Disasters
Some environmental catastrophes are instantaneous, marked by explosions and immediate waves of destruction. Others, however, operate with a sadistic slowness, seeping into the foundations of everyday life and exacting their price in the form of prolonged human agony. In the first decades of the twentieth century, in Toyama Prefecture, Japan, a mysterious and terrifying illness began to devastate the rural communities settled along the basin of the Jinzu River. Local inhabitants called the condition simply "Itai-Itai byō", which in its literal and anguished translation means the "ouch-ouch disease" or "it hurts, it hurts".
The disease was not a viral infection or an agricultural blight, but the terminal manifestation of a mass chemical poisoning caused by the operations of the giant Mitsui Mining and Smelting Company. Over the course of decades, the company discharged industrial wastewater laden with heavy metals into the crystalline waters of the river, which were used to irrigate the rice fields and for human consumption. The lethal agent at the heart of this nightmare was not mercury or lead, but cadmium (Cd).
This investigative dossier delves into the perverse chemistry of cadmium contamination, explaining how it corrodes the human body from the inside out. More than a historical account of one of the "Four Big Pollution Diseases of Japan", this article sets out an urgent contemporary warning: cadmium did not disappear with the end of irresponsible mining in Toyama. It is widely present in the technological fabric of our organisations, hidden in the batteries and printed circuit boards of legacy equipment. The negligent disposal of electronic waste threatens to rewrite the pain of Itai-Itai in the groundwater and soils of our own cities.
Ore extraction in the mountainous region of Kamioka began long before the disaster, but it reached a massive industrial scale during the Sino-Japanese wars and the First World War, when demand for lead, copper and zinc surged. Cadmium, a silvery-white heavy metal, is frequently found in nature associated with zinc ores. It is, in essence, an unwanted by-product of zinc refining.
Mitsui Mining did not possess (or neglected) the containment and treatment systems needed to handle this highly toxic by-product. For decades, tonnes of cadmium-rich slag were washed and discharged directly into the fast-flowing waters of the Jinzu River. The hydrogeology of the region did the rest of the tragic work. The river descended from the mountains and irrigated the vast flooded plains where rice — the staple of the Japanese diet — was grown.
Cadmium has a terrifying capacity for bioaccumulation and bioconcentration. As it settled into the mud of the rice paddies, the heavy metal was actively absorbed by the roots of the rice plants, concentrating in the grains. When the local population consumed the rice and the river water, cadmium entered their bodies in small but constant doses. Because the human body has no efficient mechanism for excreting cadmium (its half-life in the human organism ranges from 10 to 30 years), the poison simply accumulated decade after decade.
The biological impact of cadmium is among the cruellest ever documented by toxicology. The World Health Organisation (WHO) and the United Nations Environment Programme classify it as a systemic toxin of extreme danger.
When cadmium accumulates in the body, the first organs to collapse are the kidneys. The metal causes irreversible renal tubular dysfunction, preventing the kidneys from reabsorbing essential proteins and minerals. This leads to a massive loss of calcium and phosphorus through the urine. But cadmium's chemical cunning goes further: because of its atomic similarity to calcium, the body frequently confuses the two elements. Attempting to compensate for the loss of calcium in the blood, the organism begins to absorb cadmium directly into the bone matrix.
The result is a condition known as osteomalacia (extreme softening of the bones) combined with severe osteoporosis. The bones of Itai-Itai victims became so fragile and porous that they broke under the very weight of the body. Medical reports from the period describe patients — the vast majority of them middle-aged and elderly women — who suffered multiple bone fractures simply from coughing, breathing deeply or trying to turn over in bed. The pain was excruciating and unrelenting, justifying the anguished name of the disease. The victims ended up bedridden, with severe skeletal deformities, dying slowly of renal failure and malnutrition as their bones literally crumbled from within.
It took Japan decades of legal battles to force Mitsui Mining to compensate the victims and to fund the removal and replacement of millions of tonnes of contaminated soil from the rice fields. Today, the direct industrial discharge of cadmium is strictly prohibited. Yet the danger posed by this heavy metal has not been eradicated; it has merely changed its form and its address.
During the second half of the twentieth century and the beginning of the twenty-first, the electronics industry became the largest global consumer of cadmium. It found its way into the heart of our infrastructure primarily through rechargeable batteries. Nickel-cadmium (NiCd) was the dominant technology in power tools, radios, emergency lighting systems and, crucially, in server backup batteries, industrial uninterruptible power supplies (UPS) and legacy medical equipment.
Beyond batteries, cadmium was widely used as a stabiliser in PVC plastics (to prevent degradation from heat and UV light in IT cabling), in the yellow and red pigments of electronic casings, and in photosensitive components and relay contacts on older circuit boards.
What happens when an organisation today decides to clear out its store of obsolete IT equipment, full of these NiCd batteries and legacy boards, dumping them into ordinary commercial waste or with urban scrap dealers?
- The time bomb in landfills: NiCd batteries thrown into ordinary waste end up in landfills. Over time, the metal casing of the battery oxidises and ruptures. The cadmium leaks out and mixes with the acidic leachate of the landfill. This corrosive cocktail seeps into the soil and reaches the water table. From there, the dynamic of Itai-Itai repeats itself: contaminated groundwater reaches springs and peri-urban agricultural areas, introducing cadmium into the modern food chain.
- Fire and poisonous dust: When informal scrap collectors burn electronic waste and cables to extract base metals, the cadmium contained in the stabilised plastics and small components evaporates. Inhaling the smoke and cadmium-oxide dust is lethal, causing severe chemical pneumonitis and exponentially increasing the risk of lung cancer in the communities surrounding these clandestine operations.
The tragedy of the Jinzu River proved to us that, when it comes to cadmium, nature does not dilute the poison; it concentrates it and returns it to us through the food we eat and the water we drink. The environmental persistence of cadmium demands that organisations adopt a zero-tolerance stance towards the informal disposal of their technological legacy.
Protecting our urban aquifers against a new generation of cadmium victims depends on the immediate implementation of rigorous ESG governance practices across the technology life cycle:
- Rigorous identification of legacy batteries: The transition to lithium-ion batteries is recent. Company warehouses still hold thousands of nickel-cadmium and lead-acid batteries in out-of-use equipment, old two-way radios and alarm systems. These assets cannot be auctioned off as generic ferrous scrap; they are chemical liabilities of the very highest hazard (Class I waste).
- An absolute ban on landfilling and the informal market: Sending boxes containing old peripherals, ageing PVC cables and depreciated solar panels to informal waste pickers or rubble skips is to fund directly the contamination of your own city's soil. The leaching of heavy metals does not respect the barriers of a landfill once time and acidity act on untreated waste.
- Specialised dismantling at reverse-manufacturing plants: Corporate responsibility is only realised when electronic waste — and batteries in particular — is handed over to specialist, environmentally licensed recyclers. At these centres of excellence, NiCd batteries are separated by hand, packed into sealed containers and sent for hydrometallurgical or pyrometallurgical processing in negative-pressure environments. The cadmium is recovered chemically in enclosed furnaces, neutralising its potential for biological harm and allowing nickel and other valuable metals to be recycled safely.
The sound of weeping in the villages of Toyama was the price humanity paid to understand the brutality of heavy metals within our bodies. Today, we cannot claim ignorance. By treating the end of life of our electronic equipment and batteries with the scientific and ethical rigour that professional recycling demands, we work to keep the soil clean, the waters safe, and to ensure that technological progress is never again built upon the pain and fragility of the human body.
This technical analysis dossier is part of the "Environmental Disasters" series from Ecobraz Informa. We study the history of chemical catastrophes to promote responsible, preventive corporate action in the present. Documented disposal and partnership with specialised recycling centres are a fundamental safeguard for protecting biodiversity and public health against the hidden dangers in electronic waste.