Why was tap water contaminated in Kibichuo Town, Okayama Prefecture, where there is no PFOA factory?

Since the town announced the contamination of its tap water on October 16, 2023, the residents have been living in fear. Neither the town nor the prefecture have provided any explanation for the cause of the contamination. They have not taken any adequate measures. They only repeat words in an attempt to appease the residents.

Unable to bear the situation any longer, the residents formed a group and started a signature campaign. On November 10, they presented 1,038 signatures to Mayor Yamamoto Masanori, demanding an inspection and a refund of water bills.

On the other hand, the prefecture was closing in on the cause of the contamination.

The report of the investigation by Okayama Prefecture. From documents disclosed by Okayama Prefecture in response to Tansa’s request for disclosure of information. 

Prefectural officials visiting the rancher

The story begins on the night of October 17, the day after the town publicly announced the contamination.

Zensaku Yoshida, who owns a farm in town, was curious about the source of the contamination. The cows on his farm were fed water from the polluted Enjo Water Purification Plant. It was eventually discovered that products made from cows on his farm did not contain PFOA, but he was on the edge of closing his farm.

Zensaku’s son showed him an actual image using Google Maps’ Street View function and said, “There are a lot of strange things placed upstream of Kawahira Dam.”

The image showed a pile of “black lump.” They immediately went to the scene and found several huge black bags stacked up.

The following day, on October 18, Zensaku and his son went to see the black lumps again during the day and confirmed the black bags.

There appeared to be dozens, maybe hundreds, of bags. The bag was filled with what looked like black sand, but it had been torn open, exposing the contents. Something black was poking out.

Zensaku and his son had a hunch that this might be the cause of the contamination.

On the following day, the 19th, prefectural officials visited Zensaku. They were Fumika Shiba, general manager of the Environmental Management Division’s Chemical Substances Countermeasures Team, and Yasunori Koyama, its chief.

They seemed to be investigating the history of PFOA use among businesses in the vicinity of the Enjo Water Purification Plant in order to determine the cause of the contamination.

Zensaku reported the black bags to the prefectural officials. Shiba and Koyama left after about 15 minutes.

Further upstream

Later, Zensaku called Shiba and asked if she had checked the black bags. Shiba replied, “We’re looking into it now,” and gave no further information.

After that, Zensaku received no further contact from prefectural officials.

The prefecture continued the investigation.

Water quality tests were conducted multiple times in various locations throughout the town, and a high concentration of PFOA, 1,100 ng/L, was detected in Kawahira Dam, the water source for the Enjo Water Purification Plant.

They then evaluated the water quality of the river as it flows into the Kawahira Dam, heading upwards. The concentration increased further upstream, reaching a maximum of 62,000 ng/L.

Nonetheless, the water quality survey hit a dead end. They were unable to investigate any areas upstream from where they discovered 62,000 ng/L, since no rivers reached the surface.

That’s when they turned their attention to the black bags that Zensaku and his son had found, which was close to where they had detected the 62,000 ng/L level.

The prefecture investigated the black bags and discovered that the black substance was actually activated carbon.

Activated carbon is often used to remove PFOA from water. It absorbs PFOA from the water, making it popular in water purification plants and companies that handle PFOA.

It is highly likely that this activated carbon is the source of the PFOA contamination. The prefecture randomly sampled activated carbon from 30 locations on-site and examined its concentration. They conducted an elution test, placing activated carbon in water and measuring the concentration of PFOA dissolved in the water.

As a result, the highest concentration detected was 4.5 million ng/L, 90,000 times the national target value of 50 ng/L.

Reference: Diagram of the relative positions

Prefecture withheld the name of those responsible for pollution

On November 22, 2023, more than a month after the tap water contamination was made public, Okayama Prefecture held an emergency press conference.

The person who attended the press conference was not Governor Ryuta Ibaragi, but four other staff members from the department in charge of responding to the PFOA contamination, including Tatsuya Domoto, head of the Recycling Society Promotion Division.

The prefecture reported that it had detected 4.5 million ng/L of PFOA in used activated carbon. The activated carbon was left near the upstream of the river that flows into the Kawahira Dam. Domoto, head of the Recycling Society Promotion Division, said:

“We believe that PFOA leached from the activated carbon, soaking into the soil directly below. The possibility that used activated carbon is the source has increased even more.”

The residents saw the news on television and in the newspapers.

Identifying the source of contamination can help determine the extent of the contamination and prevent further contamination.

Furthermore, a group of residents has gathered 1,038 signatures, urging the town to conduct health research and refund water bills. It is possible to demand polluters to cover the cost.

However, Domoto did not reveal the name of the polluter who had placed the activated carbon.

“It is unclear whether it is appropriate to treat the results of elution tests and water quality surveys as equivalent, thus, we can’t determine a causal relationship.”

An elution test revealed that the activated carbon contained a high concentration of PFOA. A water quality test also found a high concentration of PFOA in a nearby river. Nonetheless, because the causal relationship between the two could not be established, the polluter’s name was kept hidden, which was bizarre logic.

The contract states “Man-ei Industry Co., Ltd.”

However, the members of the residents’ group had identified the source of the pollution themselves.

This is because the place where the black bags were placed was the “property ward.”

“Property ward” is a system adopted by Kibichuo Town and based on the Local Autonomy Act. Property ward councilors, elected by residents, manage the land and facilities owned by the government (=property ward) and lease them out at low rate to individuals, businesses, and organizations. The council meets once a year to discuss accounting. The property ward is owned by the town, and the mayor is ultimately responsible, but it is managed by the district councilors.

Kibichuo Town previously harvested a lot of matsutake mushrooms on town-owned land. The mountain was divided into plots and rented out to residents as property wards. Residents sold or ate the matsutake mushrooms they picked on the mountain.

Matsutake mushrooms are rarely harvested lately, but the property ward system remains in place. For example, the local forestry cooperative uses the property ward on the flat terrain to store timber.

Among the members of the residents’ group was a councilor of the property ward, Hiroshi Ogura.

Hiroshi checked the contract for the property ward where the activated carbon was placed.

On it was the name of a local company.

“Man-ei Industry Co., Ltd.”

A local company with 100 years of history

Man-ei Industry is a long-established company in Kibichuo Town.

Founded in 1921, the company originally produced pine oil, which was anticipated to be used as fuel for fighter planes during the war.

After the war, in 1948, Man-ei Industry succeeded in producing Japan’s first coconut shell activated carbon. Coconut shell activated carbon has the ability to adsorb chemical substances. It is used as a water purifier and deodorizer.

Man-ei Industry continued to promote its activated carbon business. In addition to coconut shells, the company developed and sold various types of activated carbon, expanding its business. After many successive generations, the company celebrated its 100th anniversary in 2021.

One of Man-ei Industry’s main businesses is “activated carbon recycling.”

The company collects the activated carbon that has absorbed the chemicals from the contractors, heat-treats it at its own factories in Kibichuo Town and Hino Town in Tottori Prefecture, and then returns the carbon back over to the contractors, ready to absorb chemicals again.

Man-ei Industry accepted activated carbon that had adsorbed PFOA from contractors outside the town.

It is this PFOA that caused the current contamination.

To be continued.

(Originally published in Japanese on July 16, 2024. Translation by Mana Shibata.)

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