The Shadow of Pollution Spreading Underground in Hamamatsu City

The Shadow of Pollution Spreading Underground in Hamamatsu City

In Hamamatsu City, Shizuoka Prefecture, illegally dumped waste has caused groundwater contamination that has seriously affected the local community. According to an investigation, the waste contained toxic chemicals that seeped into the groundwater. This caused damage to the water used for domestic and agricultural purposes by nearby residents.

In response to this problem, Hamamatsu City initiated emergency measures to identify the source of the contamination and clean up the site. To prevent recurrence, the city also strengthened its monitoring system for waste disposal companies and imposed fines on those involved in illegal dumping. The city has also introduced an underground water monitoring system and is working to minimize damage to residents.

This incident attracted widespread attention as a symbol of the nationwide groundwater contamination problem and served as an opportunity to reaffirm the importance of strengthening laws and regulations and monitoring systems.

However, Hamamatsu City has had cases of groundwater contamination confirmed in the past. For example, as of FY2006, 10 cases of groundwater contamination were confirmed in the city, which were thought to be caused by improper handling of volatile organic compounds and heavy metals, as well as by underground seepage of wastewater containing these substances.
Hamamatsu City Official Website

Because groundwater contamination can have serious effects on human health and the environment, Hamamatsu City thoroughly monitors and provides guidance to factories and business establishments that handle hazardous substances, and when contamination is found, Hamamatsu City provides guidance on appropriate cleanup measures.

Current Status of Groundwater Contamination
Hamamatsu City conducts groundwater environmental monitoring to determine the status of groundwater within the city. In the 2023 survey, 26 items for which environmental standards were established were measured at 12 sites, and all sites achieved the standards. On the other hand, trichloroethylene and tetrachloroethylene were detected in excess of the environmental standard at some points during the fixed-point monitoring in 9 areas.
Source: Hamamatsu City Groundwater Environmental Monitoring

Detection of nitrate nitrogen and nitrite nitrogen
In a survey conducted in July 2024, nitrate nitrogen and nitrite nitrogen were detected at 6 of 31 points exceeding the environmental standard (10 mg/L). These substances may be derived from fertilizers and have been identified as a cause of groundwater contamination.
Source: Hamamatsu City Survey of Nitrate-Nitrogen and Nitrite-Nitrogen

Current status of PFAS contamination
PFAS (organic fluorine compounds) have been detected in waterways and well water around the Air Self-Defense Force Hamamatsu Air Base in excess of provisional guideline values. The city is investigating and responding to the contamination.
Source: Shizuoka Shimbun News PFAS problem

Sources: [Source.
- [Recent arrests and other cases in Hamamatsu City](https://www.city.hamamatsu.shizuoka.jp/sanpai/haiki/fuhotoki/ihanjirei.html)
- [Results of a groundwater salinization study](https://www.city.hamamatsu.shizuoka.jp/kankyoho/env/tikasui/2ensui.html)