Matsumoto City's Heavy Metal Contaminated Soil Remediation Project (2007-2024)

Matsumoto City's Heavy Metal Contaminated Soil Remediation Project (2007-2024)

Since 2007, Matsumoto City has been actively working on a remediation project to address heavy metal contaminated soil. The primary contaminants, lead (Pb) and hexavalent chromium (Cr6+), have been a major concern, with focused investigations and remediation efforts covering approximately 12000 square meters near Matsumoto Station and 8500 square meters in the Asama Onsen area. Shimizu Corporation introduced electrolytic purification technology, reducing the remediation cost of lead-contaminated soil to 30000 yen per ton, achieving an annual processing capacity of approximately 4000 tons. Additionally, DOWA Eco-System introduced iron powder reduction technology, which shortened the remediation period for hexavalent chromium from the conventional 12 weeks to 6 weeks. These initiatives have enabled the treatment of over 80% of the 5000 tons of contaminated soil annually, with remediated land being utilized for constructing hotels and commercial facilities. During the 2010s, fur
ther contaminated areas, such as the Kiri district, were identified and remediated. For instance, in 2015, high concentrations of lead were detected on 1200 square meters of land in the Kiri district, and remediation costs amounted to approximately 300 million yen. During this period, the Matsumoto City Environmental Energy Division conducted over 300 investigations, allocating a budget of approximately 2 billion yen to the remediation projects.

In the 2020s, Matsumoto City has seen an increase in the designation of "areas requiring measures" and "areas requiring notification prior to land alteration" under the Soil Contamination Countermeasures Act. As of 2024, specific sites such as Kaname 478 (259.83 square meters, fluorine concentration of 5.5 mg/L) and Yoshino 105-1 (158.09 square meters, hexavalent chromium concentration of 8.2 mg/L) have been designated, and remediation efforts are ongoing. Shimizu Corporation's on-site plant can now process up to 100 tons of contaminated soil per day, and DOWA Eco-System has successfully reduced the cost of hexavalent chromium remediation to 20000 yen per ton using iron powder reduction technology. Citywide, approximately 6000 tons of contaminated soil are generated annually, with an estimated annual remediation cost of 1.8 billion yen. Matsumoto City plans to utilize 50% of the remediated land for new facility construction by 2025, contributing significantly to reducing heal
th risks for residents and utilizing tourism resources. The Matsumoto City Environmental Energy Division, in collaboration with the local company Environmental Science Co., Ltd., aims to further improve efficiency and reduce costs through the adoption of advanced technologies.