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EM Application Report from Fukushima, Japan (III)

EM Application Report from Fukushima, Japan (III)


Experiments on the reduction of radioactive contamination on farmland

THis report is about one of the experiments conducted in lidate, Fukushima by our R&D department in cooperation with the local fruit farmers from May 2011 to Decmber 2013. This experiment was ended when the decontamination declined by the Japanese Government started.

This experiment was conducted to determine the effect of EM on reducation of radioactive contamination on fruit farmland that has been  utilizing EM.
Three treatment areas were prepared on 2,000m2 bluebery farm: EM Treatment area, which was sprayed with Activated EM・1 (AEM) and phototrophic bacteria, EM+Organic Material(OM) area, which was sprayed with AEM and organic matters, and COntrol area/ Control area adjoined both EM Treatment area and EM+OM area/


Radioactive cesium level of the soil in EM Treatment area was approx.20,000Bq/kg at the beginning of the experiment and was dropped to approx. 5,000Bq/kg in Julym which means that there was approx. 15,000Bq/kg '75%) reduction in 2 months ater spraying AEM. Also, EM+OM area had a decrease of radioactive cesium level (Figure1).

We suspected this large reduction of radioactive cesium level might be the result of rainfall, which helps radioactiv cesium to migrate down into the soil so we analyzed a sample soil at a depth of 15-30cm from the survace soil. According to the analysis, the radioactive cesium level for the sample soil was approx. 250Bq/kg: threfore, it was considered that

Table 1: Level of radioactive cesium (Bq/kg) in the soil
(sampled on Jly 17, 2011)


there was no influence of rainfall (Table 1)
This analysis result was consistent with a report from the MAFF that when the radioactive cesium is strongly bounded with clay particles of the non-plowed soil, 95% of radioactive cesium will stay at the 2.5cm depth from the soil surface. However, the decrease (approx. 75%) of radioactive cesium level was also seen in Control are, which was next to the EM Treatment area. We believed this reduction was due to the expansion of AEM in the soil we sprayed in the EM Treatment area. THus, we measured the soil of blueberry farm across the street where is aways from EM Treatment area and this soil still had the high value of radioactive cesium level with 15,000Bq/kg.

The reason of this large reduction is still under invenstigation. However, we are assuming that microorganisms' activity in the soil might somehow affected the reduction of radioactive cesium level based on the following facts. There has been no reports we could find of such phenomenon: 75% decrease of raidioactive cesium level in short period under natural conditions. The result of the study regarding the change of radioactive cesium level on local farms (orchard, farmland and rice paddy) that have been using EM or EM compst for more than 15 years showed that the radioactiv cesium level (137Cs) on their soils was decreased more rapidly compared to the theoretical decay value of 137Cs that has a half-life about 30 years (Figure 2).


Furthermore, according to the experiment about cow manure compost and its effluent fermented by EM on the Takizawa Dairy Farm (refer to EMRO Newsletter WInter 2014), EM area with EM fermented compost and effluent, declines more every year compared with the Chemical area.
This is also another reaswon why we consider that microorganisms' activity in the soil might influenfe the reduction of radioactive cesium (Figure 3)
EM Support Project by R&D Department, EMRO. Case Studies on EM Reconstruciton Support Project 2012, 2013, 2015.
Takizawa Dairy Farm, EM Application Report from Fukushima, Japan. EMRO Newsletter WInter 2014.

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