Water Pollution In Japan: Understanding The Primary Causes

Water pollution in Japan has been a significant issue since the Meiji period (1868-1912), with the country's rapid economic and industrial growth contributing to contaminated water sources. The pollution has resulted in outbreaks of diseases, including mercury and cadmium poisoning, and the occurrence of large fish kills, with the fishing sector being a critical part of Japan's economy. While Japan has implemented stricter environmental protection measures and regulations, such as the Water Pollution Control Act, challenges remain in addressing industrial discharge, agricultural runoff, untreated waste, and plastic pollution. The country's high-tech industries and nuclear power plants have also contributed to water contamination, with ongoing concerns about the release of treated radioactive water from the Fukushima Daiichi nuclear power plant.

Industrial discharge

Japan's rate of pollution has improved since the 1950s and 1960s, but water pollution remains a significant issue. The primary cause of water pollution in Japan is industrial discharge, with over 40,000 people affected by water pollution-related diseases caused by factory runoff during the country's rapid economic growth in the 1950s and 1960s.

During this period, Japan's heavy industrialization led to the emission of toxic chemicals and pollutants into water sources. One notable example was the contamination of Minamata Bay, caused by the Chisso Corporation's dumping of methylmercury, a by-product of their chemical manufacturing process. This resulted in a disease called Minamata, with symptoms including signs of methylmercury poisoning such as chronic bronchitis and pulmonary emphysema. Another incident, known as "itai-itai" disease, occurred due to cadmium poisoning in the drinking water from the Jinzū River basin, traced back to the Mitsui Mining and Smelting Company.

The Japanese government has implemented stricter regulations and laws to address industrial water pollution. The Water Pollution Control Law, first enacted in 1970 and revised in 1989 and 1996, mandates that factories regulate the disposal of dangerous chemicals and grants governors the power to order polluters to take responsibility for cleanup efforts. As a result of these measures, water pollutant loads dropped by 90% within 20 years, demonstrating the effectiveness of stricter standards.

However, industrial discharge remains a concern, with Japan's high-tech industries, such as integrated circuit production, contributing to groundwater pollution. Solvents like trichloroethylene and tetrachloroethylene, used in circuit production and dry cleaning, respectively, are carcinogenic and pose risks to both aquatic life and human health. Additionally, the release of radioactive water from the Fukushima Daiichi nuclear power plant, damaged in the 2011 earthquake and tsunami, has raised concerns about potential long-term environmental consequences.

While Japan has made significant progress in reducing industrial water pollution, the country continues to face challenges in managing the complex and persistent issue of industrial discharge.

Agricultural runoff

Chemical fertilisers and pesticides used in agriculture can contaminate water bodies, leading to eutrophication and ecosystem damage. These chemicals can cause toxic effects on aquatic life, including fish neoplasms and skeletal anomalies. Additionally, agricultural runoff can introduce pathogens and bacteria into water sources, leading to water-borne diseases such as cholera, typhoid, and various types of infections.

The impact of agricultural runoff on water pollution is particularly prominent during storm flow conditions, when increased rainfall and runoff can carry pollutants from agricultural lands into nearby water bodies. This non-point source pollution is challenging to regulate and control due to its dynamic and unpredictable nature.

Furthermore, agricultural practices can also indirectly contribute to water pollution through the contamination of food crops. Irrigation with polluted water or washing vegetables in contaminated water can introduce pathogens and toxic chemicals, such as mercury compounds, into the food supply, posing risks to human health.

To address these issues, Japan has implemented robust pollution control programs and tightened regulations on agricultural practices. By improving wastewater treatment and promoting sustainable farming methods, Japan aims to reduce the impact of agricultural runoff on its water resources and protect the health and well-being of its citizens and aquatic ecosystems.

Untreated sewage

Japan's rate of pollution has improved significantly since the 1950s and 1960s, but water pollution remains a pressing issue. One of the primary causes of water pollution in Japan is untreated sewage.

Untreated domestic waste is a significant contributor to water pollution in Japan, with human waste being released into water bodies without proper treatment. This can occur due to outdated or inadequate sewage systems and infrastructure, as well as a lack of access to centralized wastewater treatment facilities in certain areas. This issue is particularly prevalent in rural or less developed regions, where the necessary infrastructure for sewage treatment may not be available or properly maintained.

Additionally, untreated sewage can introduce excessive nutrients, such as nitrogen and phosphorus, into aquatic ecosystems, leading to a process known as eutrophication. Eutrophication can cause excessive algae growth, depleting oxygen levels in the water and creating "dead zones" where aquatic life cannot survive. This disruption in the natural balance of aquatic ecosystems can lead to the decline or disappearance of fish and other aquatic organisms, impacting both the environment and industries that depend on them, such as Japan's significant fishing sector.

Furthermore, untreated sewage often contains harmful chemicals and pollutants that can accumulate in water bodies. These chemicals may include pesticides, pharmaceuticals, heavy metals, and toxic industrial compounds. When released into water, these chemicals can contaminate aquatic environments, leading to bioaccumulation in aquatic organisms and potentially entering the food chain. This can result in the contamination of fish and shellfish, which are an important part of the Japanese diet, posing risks to human health and causing concerns about the chronic effects of consuming contaminated seafood.

Mercury and cadmium poisoning

Water pollution in Japan has improved since the rapid economic growth of the 1950s and 1960s. However, it still poses a significant risk to the country's health and environment. One of the major pollution problems in Japan has been outbreaks of mercury and cadmium poisoning in humans, as well as in fish and other aquatic life.

Mercury poisoning, also known as Minamata disease, was first discovered in 1956 in the city of Minamata, Kumamoto Prefecture, Japan. It was caused by the release of methylmercury in industrial wastewater from a chemical factory owned by the Chisso Corporation. The highly toxic chemical bioaccumulated and biomagnified in shellfish and fish in Minamata Bay and the Shiranui Sea. When these were consumed by the local population, it resulted in mercury poisoning, causing severe health issues and even death. Symptoms of Minamata disease include ataxia, numbness in the hands and feet, general muscle weakness, loss of peripheral vision, and damage to hearing and speech. In extreme cases, it can lead to insanity, paralysis, coma, and death within weeks of the onset of symptoms.

The Japanese government has acknowledged the issue and taken steps to address it. By December 1959, wastewater treatment facilities were installed, but they failed to effectively reduce the levels of organic mercury being released into the Shiranui Sea. It was not until 1968 that the Chisso Corporation stopped production using mercury catalysts, and in 2004, they were ordered to clean up their contamination.

In addition to mercury poisoning, cadmium poisoning has also been a concern in Japan. Cadmium is a toxic metal that can accumulate in the body over time, leading to adverse health effects. While the specific sources and impacts of cadmium poisoning in Japan require further investigation, it is known that industrial discharge, agricultural runoff, and untreated domestic waste are significant contributors to water pollution in the country.

To combat water pollution, Japan has implemented stricter water pollution standards, leading to a significant reduction in water pollutant loads. Additionally, the government has tightened regulations around industrial emissions and made significant investments in recycling and waste management technologies. These efforts are crucial in mitigating the health and environmental risks posed by water pollution, especially considering Japan's strong dietary preference for fish and shellfish, which are vulnerable to contamination.

Radioactive water

Water pollution in Japan is mainly caused by industrial discharge, agricultural runoff, and untreated domestic waste. Japan is one of the world's top consumers of plastic, with the second-highest per capita plastic waste emissions. As a result, plastic pollution has become a significant issue for the country, with microplastic rates in coastal waters being 27 times higher than the global average.

Another major cause of water pollution in Japan is the release of radioactive water from the Fukushima Daiichi nuclear power plant into the Pacific Ocean. In 2023, the Japanese government announced its plan to release treated radioactive water from the plant, which was destroyed in the 2011 Tohoku earthquake and tsunami, into the ocean. This decision has sparked controversy and raised concerns among the public and scientists both domestically and internationally.

The Japanese government and Tepco, the plant operator, have implemented measures to address the issue. Tepco filters the Fukushima water through the Advanced Liquid Processing System (ALPS), which removes most radioactive substances except for tritium and carbon-14. The water then undergoes further treatment and is diluted with seawater before being released into the ocean through an underground tunnel. The Japanese government maintains that the final level of tritium in the processed water is much safer than the regulatory standards for nuclear waste discharge.

However, critics argue that the potential risks to the ocean bed and marine life have not been adequately assessed. Some scientists express concern about the inability to remove radioactive substances once they enter the ocean, and the potential impact on fisheries in the area. International opposition to Japan's plan has been mounting, with countries like South Korea seeing public protests and China suspending aquatic imports from Japan.

While Japan's overall rate of pollution has improved since the 1950s and 1960s, the presence of radioactive water and plastic pollution in its waters continues to pose significant challenges and risks to the country's environment and economy.

Frequently asked questions