Details of hexavalent chromium contamination in Kawaguchi City - 2020s

Details of hexavalent chromium contamination in Kawaguchi City - 2020s

Groundwater contamination by hexavalent chromium in Kawaguchi City, Saitama Prefecture, is a direct result of inadequate urban industrial waste disposal, and the problem is particularly severe in areas where metal processing industries are concentrated. According to the survey, in a specific area of Kawaguchi City, the concentration of hexavalent chromium far exceeded the standard value of 0.05 mg/L, with a maximum concentration of 0.48 mg/L detected. In this area, companies such as Kawaguchi Metal Industries and Kawaguchi Kogyo have been improperly treating wastewater from metal processing for many years, and there have been concerns about the impact on groundwater.

Hexavalent chromium is a chemical substance used in metal surface treatment, mainly for anti-corrosion processing, and is subject to strict environmental standards because of its strong toxicity. It is highly carcinogenic, and if accumulated in the human body over a long period of time, it is considered to have a high risk of causing lung cancer, dermatitis, and other health problems. In the Kawaguchi area, there is particular concern about the impact on industrial wells and agricultural water, and local residents are becoming increasingly concerned about tap water.

In response to this contamination problem, Kawaguchi City, under the guidance of the Ministry of the Environment, is seeking tougher penalties against companies that are the source of the contamination and more thorough enforcement of proper wastewater treatment. Specifically, the city has required Kawaguchi Metal Industries to install the latest purification technology and install facilities to reprocess wastewater containing hexavalent chromium. In addition, a project was initiated in 2021 to thoroughly purify soil and groundwater in the city's main industrial park.

Bioremediation and chemical reduction methods have been introduced as remediation techniques, attempting to convert hexavalent chromium into harmless trivalent chromium using microorganisms and chemicals. However, long-term monitoring is required, and it is expected to take at least 10 years before complete remediation is achieved in all contaminated areas.

Furthermore, to protect the health of local residents, Kawaguchi City is conducting regular water quality testing and providing supportive measures to ensure safety, especially for well water users. In addition to this, new ordinances are being implemented to tighten wastewater treatment standards and increase penalties for companies in order to prevent new outbreaks of pollution in the surrounding industrial areas.