Tag Archives: radioactive soil

How Soil Can Fight Pollution

Soil biodiversity is essential for most of the ecosystem services and functions that soils
provide and perform. Soil microbes (i.e., bacteria, fungi) and microfauna (i.e., protozoa
and nematodes) transform organic and inorganic compounds into available forms. These transformations are critical for nutrient cycling and availability, for plants, and other species growth, for cycling of soil organic matter and carbon sequestration, and for the filtration, degradation, and immobilization of contaminants in water and soil.

An important part of the food web is represented by mesofauna, such as springtails and mites, which accelerate litter decomposition and enhance nutrient cycling and availability (especially nitrogen), and predators of smaller soil organisms.

Soil macro, and megafauna such as earthworms, ants, termites, and some mammals act as ecosystem engineers that modify soil porosity, water and gas transport, and bind soil particles together into stable aggregates that hold the soil in place and thus reduce erosion.

Soil biodiversity can mitigate threats to ecosystem services, for instance by acting as a powerful tool in bioremediation of contaminated soils. Biostimulation and bioaugmentation are environmentally sound strategies that contribute to the filtration, degradation, and immobilization of target contaminants. Furthermore, the integral use of organisms such as microbes (bioaugmentation), plants (phytoremediation) and earthworms (vermiremediation) as a bioremediation strategy in hydrocarbon-contaminated soils has proven to be a viable alternative for increasing hydrocarbon removal. On the other hand, soil macrofauna, such as earthworms, termites, and ants, play an important role in improving soil structure and aggregation, which can improve resistance to soil erosion caused by wind and water.

Excerpt from FAO, State of Knowledge of Soil Biodiversity, Report 2020

A Huge Headache: the Radioactive Water at Fukushima

What to do with the enormous amount of radioactive  water, which grows by around 150 tons a day at Fukushima, is a thorny question, with controversy surrounding a long-standing proposal to discharge it into the sea, after extensive decontamination.  The water comes from several different sources: Some is used for cooling at the plant, which suffered a meltdown after it was hit by a tsunami triggered by a massive earthquake in March 2011.  Groundwater that seeps into the plant daily, along with rainwater, add to the problem.

A thousand, towering tanks have now replaced many of the cherry trees that once dotted the plant’s ground. Each can hold 1,200 tons, and most of them are already full.  “We will build more on the site until the end of 2020, and we think all the tanks will be full by around the summer of 2022,” said Junichi Matsumoto, an official with the unit of plant operator TEPCO in charge of dismantling the site.

TEPCO has been struggling with the problem for years, taking various measures to limit the amount of groundwater entering the site.  There is also an extensive pumping and filtration system, that each day brings up tons of newly contaminated water and filters out as many of the radioactive elements as possible.

The hangar where the decontamination system runs is designated “Zone Y” — a danger zone requiring special protections.  All those entering must wear elaborate protection: a full body suit, three layers of socks, three layers of gloves, a double cap topped by a helmet, a vest with a pocket carrying a dosimeter, a full-face respirator mask and special shoes.  Most of the outfit has to burned after use.

“The machinery filters contain radionuclides, so you have to be very protected here, just like with the buildings where the reactors are,” explained TEPCO risk communicator Katsutoshi Oyama.  TEPCO has been filtering newly contaminated water for years, but much of it needs to go through the process again because early versions of the filtration process did not fully remove some dangerous radioactive elements, including strontium 90.

The current process is more effective, removing or reducing around 60 radionuclides to levels accepted by the International Atomic Energy Agency (IAEA) for water being discharged.  But there is one that remains, which cannot be removed with the current technology: tritium.

Tritium is naturally present in the environment, and has also been discharged in its artificial form into the environment by the nuclear industry around the world.  There is little evidence that it causes harm to humans except in very high concentrations and the IAEA argues that properly filtered Fukushima water could be diluted with seawater and then safely released into the ocean without causing environmental problems.

But those assurances are of little comfort to many in the region, particularly Fukushima’s fishing industry which, like local farmers, has suffered from the outside perception that food from the region is unsafe.

Karyn Nishimura, At Fukushima plant, a million-ton headache: radioactive water, Japan Times, Oct. 7, 2019

Nuclear Waste in Australia: rusting and leaking

The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is the federal government agency for scientific research in Australia.
CSIRO faces a $30 million clean up bill after barrels of radioactive waste at a major facility were found to be “deteriorating rapidly” and possibly leaking.

An inspection found “significant rusting” on many of the 9,725 drums, which are understood to contain radioactive waste and other toxic chemicals.  Much of the radioactive waste was trucked to Woomera from Sydney in the mid 1990s.  CSIRO flagged a $29.7 million budget provision for “remediation works” at a remote location in its latest annual report.

Almost 10,000 drums of radioactive waste are stored at a CSIRO facility in Woomera, South Australia.  The Woomera facility is currently one of Australia’s largest storage sites for low and intermediate-level radioactive waste.   A damning report of the Woomera facility was issued by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) after an inspection in April 2016.   “Evidence was sighted that indicates the drums are now beginning to deteriorate rapidly,” read the report, seen by Fairfax Media.  “Significant rust on a number of the drums, deterioration of the plastic drum-liners and crushing of some stacked drums was observed.

Tests confirmed the presence of radioactive isotopes at one location and inspectors said there was a possibility the drums were leaking.”Although unlikely, there is the possibility that the presence of deceased animals such as rodents and birds may indicate that some of the drums, which contain industrial chemicals, may be leaking into the environment.”  The mixture of water and concentrated radioactive material inside some of the drums also had the potential to produce explosive hydrogen gas, inspectors found.

They also noted CSIRO had little knowledge of what was inside many of the barrels, some of which are believed to date back more than 50 years.  “Without full knowledge [of] the contents of the drums, risks cannot be fully identified and risk controls cannot be appropriately implements to protect people and the environment,” inspectors noted in the report.

Many of the drums are understood to contain contaminated soil generated by government research into radioactive ores at Melbourne’s Fishermans Bend throughout the 1940s and 1950s.  The toxic soil was discovered by the Department of Defence in 1989, who sent it to Sydney’s Lucas Heights facility before it was palmed off to Woomera in 1994.

The country’s other major radioactive waste storage facility at Lucas Heights, Sydney, is rapidly approaching full capacity. 

Coupled with issues at the CSIRO site, the revelations highlighted the urgent need for a national radioactive waste storage solution, experts said.

Excerpts from Rusted barrels of radioactive waste cost CSIRO $30 million, Sydney Morning Herald, Mar. 13, 2017

A Schoolyard at Fukushima

Highly radioactive soil that should by law be removed by the central government has been left dumped in the corner of a schoolyard here because the construction of a local storage site for waste has been stalled.  Students at the school were not given an official warning that the radioactive soil was potentially hazardous to their health.

When a teacher scooped up soil samples at the site and had their radiation levels measured by two nonprofit monitoring entities–one in Fukushima and another in Tokyo–the results showed 27,000-33,000 becquerels of radioactive cesium per kilogram. The law stipulates that the central government is responsible for disposing of waste measuring more than 8,000 becquerels per kilogram. But as a central government project to build an interim storage site for highly radioactive waste near the nuclear power plant has been stalled, the school appears to have no alternative to indefinitely keeping it in the schoolyard…

Radioactive soil turns up at Fukushima high school,The Asahi Shimbun, June 15, 2016