written by James Ko
On April 26th 1986, reactor #4 at the Chernobyl nuclear power plant in
Ukraine exploded, due to the "human factor". The result was a
total release of approx. 2 *1018 Bq, the most being shortlived
nuclides like Iodine-131, and 4* 016 Bq was Cs-137. The local
effect was, of course, disastrous. An area of 870 square kilometres received
a surface contamination of >300 MBq/m2 and much land eventually had
to be banned for agricultural production. In the vicinity of hernobyl and
Pripyat, the worst affected town, large amounts of heavier radionuclides
were deposited, e.g. Pu-239 and Sr-90. As a direct result of the accident
30 persons died, most of these were firefighters who managed to put out
the fire in the r actor. Already, an over-frequency of thyroid cancer among
children have been reported from Belorussia, and it seems inevitable that
there will be an increased cancer frequency in the areas relatively close
to the reactor.
More comprehensive information on the accident and the consequences in the vicinity of Chernobyl can be found at this Ukrainian site, the Polyn-project.
On the 27th the radioactive cloud reached Sweden, and at the same time it started to rain. This meant that even in Sweden the effects of the Chernobyl accident was very serious, though of course on quite another scale than in the vicinity of Chernob l. It will most likely not be possible to deduce any cancer-cases directly from the accident.
The most affected areas in Sweden, where it rained during the critical days, received from 25 to 200 kBq/m2 of Caesium-137. Other areas, i.e. most of Sweden, received comparatively low activities, in the range of 0,2 to 5 kBq/m2 This is a clickable map. The sensitive areas are the black and red parts, Sweden as a whole, and the rest, respectively. Reproduced with the kind permission of Tone D. Selnaes, Norwegian Institute f Energy Technology.
The next phase in Sweden was to try and determine the risk situation for the population in the areas worst affected (black on the map). It was determined that personal protection was not necessary, and the emphasis was instead shifted towards foo production. The accident happened short before the grazing season in the affected areas would begin, and it was decided to keep all livestock stabled until further notice. Soon it was possible to let animals in most of Sweden begin their grazing, b t in some areas around The Gaevle farmers had to wait until the end of June to let their animals out. These authority measures, though sometimes maybe too strict, meant that very little milk had to be wasted due to excessive activity. The limits for food were set to 300 Bq/kg, but the dairies set their levels to a tenth of this. However, some milk had to be discarded, and this was done by spreading it on farmland. No negative effects were seen from this.
For the farmers these countermeasures were of course troublesome. Their winterfodder was on the verge of running out, as it usually is at this time of year, and now they had to keep their animals indoors. The government gave subsidies for buying odder from other parts of the country, but the situation was much the same everywhere. By using more grainfeed than usual it was possible to make it work anyway. It now became apparent that it was necessary to make sure that this years harvest could be used for winterfodder the next season. Intensive activity, both at the University of Agricultural Sciences and at the local agricultural extension authorities, lead to improvement of current technology, and very little fodder eventually had to be discarded.
Our department now has research on the effects of the Chernobyl accident in the agricultural system mainly in the areas around Gaevle, in the county of Vsternorrland and in the county of Jmtland. Much of the research in the forest ecosystem is conducted in an area called Harbo, in the county of Vstmanland.
If you feel need for more information on the Chernobyl-accident, feel free to contact me at Sverker.Forsberg@radek.slu.se .
Just after midnight on March 24, 1989, the Exxon Valdez, an oil tanker, hit Bligh Reef in the Prince William Sound dumping 11 million gallons of crude oil into the pristine blue waters, the worst oil spill in the United State's history. The Prince William Sound, an island body of water off of Alaska's southern coast, is home to one of the country's richest concentrations of wildlife, as well as booming fishing industries and native villagers. The Sound also serves as a thoroughfare for the Alyeska Pipeline's oil tankers shipping oil to the consumers of the lower 48 states. Alaska's natives, fishermen and environmentalists have always been weary of the oil industry's foothold in the region for the potential risks of an oil spill. On that spring night their worst fears were realized. This accident would touch off a battle between the native Alaskans and the oil industry, both in the court room and in the press, over not only the culpability for the accident but the future of the region and the future of oil transportation and oil spill readiness. Scientists and environmentalists would come together to clean the beaches, protect the wildlife, and assess the damage. Exxon led the clean up effort with 11,000 workers in the summer months expending some $1.9 billion dollars. Sea otter rehabilitation centers were established while salmon and herring fisheries were closely isolated and monitored. Even after all the initial efforts at clean up, the damage from this massive spill was unavoidable and extensive. Even today, over five years later, scientists are still attempting to determine the ecological damage caused by the spill.
The Exxon Valdez oil spill in Prince William Sound, Alaska, in March 1989, was the largest crude spill to date in US waters. It prompted many studies on the fate, transport, and effects of the oil on biota in Alaskan waters, as well as on archaeological sites.
This site consists of 25 research paper abstracts presented at an ASTM Symposium in April 1993. The intorductory chapter summarizes topics and highlights of those papers, covering chemistry and fate, shoreline impacts, effects on fish, fisheries and wildlife, and impacts on archaeological sites, and it discusses some of the issues arising from the study of this spill.
In addition to these abstracts, the following sites provide useful information on the effects of oil spills on the environment:
The Oil Spill. Shortly after midnight on March 24, 1989, the T/V
Exxon Valdez ran aground on Bligh Reef in Prince William Sound, Alaska,
spilling almost eleven million gallons of North Slope Crude oil. It was
the largest tanker spill in Unit d States history. That spring the oil
moved along the coastline of Alaska, contaminating portions of the shoreline
of Prince William Sound, the Kenai Peninsula, lower Cook Inlet, the Kodiak
Archipelago, and the Alaska Peninsula. Oiled areas includ a National Forest,
four National Wildlife Refuges, three National Parks, five State Parks,
four State Critical Habitat Areas, and a State Game Sanctuary. Oil eventually
reached shorelines nearly 600 miles southwest from Bligh Reef where the
spill ccured. The spill area includes all of the shoreline oiled by the
spill, severly affected communities, and adjacent uplands to the watershed
divide.
Response. During 1989, efforts focused on containing and cleaning up the spill, and rescuing oiled wildlife. Skimmers worked to remove oil from the water. Booms were positioned to keep oil from reaching salmon hatcheries in Prince William ound and Kodiak. A fleet of private fishing vessels known as the "Mosquito Fleet" played an important role in protecting these hatcheries, assisting the skimmers, and capturing oiled wildlife and transporting them to rehabilitation centers. Exxon began to clean up beaches under the direction of the U.S. Coast Guard with advice from federal and state agencies and local communities. Several thousand workers cleaned shorelines, using techniques ranging from cleaning rocks by hand to high-press re hot-water washing. Fertilizers were applied to some oiled shorelines to increase the activity of oil-metabolizing microbes, an activity known as bioremediation.
The 1989 shoreline assessment, completed after the summer cleanup ended, showed that a large amount of oil remained on the shorelines. In the spring of 1990, the shoreline was again surveyed in a joint effort by Exxon and the state and federal govenments. The survey showed that much work remained to be done. The principal clean-up method used in 1990 was manually removing the remaining oil, but bioremediation and relocation of oiled beach material to the active surf zone were also used in s me areas.
Shoreline surveys and limited clean-up work occured in 1991, 1992, 1993, and 1994. In 1992, crews from Exxon and the state and federal governments visited eighty-one sites in Prince William Sound and the Kenai Peninsula. They reported that an esti ated seven miles of the 21.4 miles of shoreline surveyed still showed some surface oiling. This number does not include oiling that may have remained on shorelines set aside for monitoring natural recovery. The surveys also indicated that subsurfa e oil remained at many sites that were heavily oiled in 1989. No sites were surveyed on Kodiak Island or the Alaska Peninsula in 1992. Earlier surveys suggested that most of the light oil (scattered tar balls and mousse) which remained on Kodiak I land and the Alaska Peninsula would degrade by 1992. While there may be a few exceptions, the surveys determined that the cost and potential environmental impact of further cleanup was greater than the problems caused by leaving the oil in place. The 1992 cleanup and the 1993 shoreline assessment were concentrated in those areas where oil remained to a greater degree - Prince William Sound and the Kenai Peninsula.
In 1994, Restoration workers performed manual treatment to accelerate degradation of surface oil on approximately a dozen important subsistence and recreating beaches in western Prince William Sound. They also performed manual treatment to accelera e degradation of subsurface oil beneath approximately a dozen oiled mussel beds in protected areas of western Prince William Sound.
Natural Resource Damage Assessment. During the first summer after the spill, one state and three federal government agencies directed the Natural Resource Damage Assessment field studies to determine the nature and extent of the injuries as needed for litigation purposes. The federal agencies were the U.S. Department of the Interior, U.S. Department of Agriculture and the National Oceanic and Atmospheric Administration. The state agency was the Alaska Department of Fish and Game. Ex ert peer reviewers provided independent scientific review of ongoing and planned studies and assisted with synthesis of results. Most damage assessment field studies were completed during 1991.
In the late 1940's, about 80 kilometers north of the city of Chelyabinsk,
an atomic weapons complex called "Mayak" was built. Its existence
has only recently been acknowledged by Russian officials, though, in fact,
the complex, bordered to the west by the Ural Mountains, and to the north
by Siberia, was the goal of Gary Powers's surveillance flight in May of
1960.
For forty-five years, the Chelyabinsk province of Russia was closed to
all foreigners. Only in January of 1992 did President Boris Yeltsin sign
a decree changing that. As a result, western scientists who studied the
region, declared Chelyabinsk to be the most polluted spot on earth.
Plutonium and Tritium for Soviet nuclear weapons are produced at three
closely guarded locations, each of which includes a "closed"
city for workers. These cities do not appear on maps, and until recently,
travel to and from them was all but prohib ted. Even now, foreign visitors
have been allowed to see only two of the sites. Each of the sites has an
official name, often including a number that indicates a post office address,
but each was known by another name or names abroad as well as in the Soviet
Union.
The complex officially known as Chelyabinsk-40 is located in Chelyabinsk
province, about 15 kilometers east of the city of Kyshtym on the east side
of the southern Urals. It is situated in the area around Lake Kyzyltash,
in the upper Techa Rive drainage basin among numerous other interconnected
lakes. Between Lake Kyzyltash and Lake Irtyash is Chelyabinsk-65, the military-industrial
city was once called Beria, but today inhabitants call it Sorokovka("forties
town").
Another Mayak laboratory, the All-Union Institute of Technical Physics,
is located just east of the Urals, 20 kilometers north of Kasli. It is
better known by its post office box, Chelyabinsk-70. It was opened in 1955,
shortly after Lawrence Liver ore National Laboratory in the United States.
Chelyabinsk-65, was variously reported to have 83,000 inhabitants and "almost
100,000 people." Chelyabinsk-40, the reactor complex, covers some
90 square kilometers, according to a recent ministry report, and is run
by the production associatio Mayak("beacon" or "lighthouse").
All the reactors are located near the southeast shore of Lake Kyzyltash
and relied on open-cycle cooling: water from the lake was pumped directly
through the core.
Probably fashioned after the U.S. Hanford Reservation in the state of Washington,
Chelyabinsk-40 was the first Soviet plutonium production complex. Construction
was started on the first buildings of the new city in November 1945. Some
70,000 i mates from 12 labor camps were reportedly used to build the complex.
It is here that the physicist Igor Kurchatov, working under Stalin's deputy
Lavrenti Beria, built the first plutonium production reactor, called "Anotchka"
or A Reactor, in just 1 months.
The people of the Chelyabinsk Region have suffered no less than three nuclear
disasters:
For over six years, the Mayak complex systematically dumped
radioactive waste into the Techa River, the only source of water for the
24 villages which lined its banks. The four largest of those villages
were never evacuated, and only recent y have the authorities revealed to
the population why they strung barbed wire along the banks of the river
some 35 years ago. Today, as a result of Kyshtym-57's (a local environmental
group lead by Louisa Korzhova) fight for radiation victims, a ne law was
introduced which allows residents of Muslyumovo to resettle themselves
elsewhere. Unfortunately, the new law is limited only to one village.
In 1957, the area suffered its next calamity when the cooling
system of a radioactive waste containment unit malfunctioned and exploded.
About two million curies spread throughout the region, exposing to radiation
over a quarter million peop e. Less than half of one percent of these people
were evacuated, and some of those only after years had passed.
The third disaster came ten years later. The Mayak
complex had been using Lake Karachay as a dumping basin for its radioactive
waste since 1951. In 1967, a drought reduced the water level of the lake,
and gale-force winds spre d the radioactive dust throughout twenty-five
thousand square kilometers, further irradiating half a million people with
five million curies.
Chelyabinsk-40, or the Kyshtym complex is best known to the outside world
as the site of a disastrous explosion in 1957, only recently acknowledged
by Soviet officialdom. The tanks were entirely immersed in, and cooled
by, water. But the monit ring system was defective. The system failed in
one of the tanks, however, and the waste began to dry out. On September
29, 1957, exploded with a force equivalent to 70-100 tons of TNT. Seventy
or 80 metric tons of waste containing some 20 millio curies of radioactivity
was ejected -- about one-fourth the amount released in the 1986 Chernobyl
accident.
About 90 percent of the radioactivity fell out immediately around the vessel.
The rest formed a kilometer-high radioactive cloud that was carried through
Chelyabinsk, Sverdlovsk, and Tumen provinces.
There were 217 towns and villages with a combined population 270,000 people
in the area that was contaminated to greater than 0.1 curies of strontium
90 per square kilometer. By comparison, the total strontium 90 fallout
at this latitude from p st atmospheric tests is 0.08 curies per square
kilometer. Virtually all water supply sources in the area were contaminated.
Evacuation of the most highly contaminated areas, where 1,100 people lived,
was not completed until 10 days after the accid nt. Other areas were evacuated
a year later, after the population had consumed radioactive food. In the
years following the accident, 515 square miles of land was plowed under
or removed from agricultural use; all except 80 square kilometers was r
turned to use by 1978.
About 10,000 people lived in the 1,000-square-kilometer area contaminated
with more than two curies of strontium 90 per square kilometer. One-fifth
of these people eventually showed a reduction of leukocytes in their blood.
There are no record of deaths caused by the accident.
This accident is only part of Chelyabinsk-40's deadly legacy, because there
was no management of radioactive waste at all before September 1951: for
years the high-level nuclear waste was simply discharged directly into
the Techa River. And ove the years, workers at the complex have been exposed
to astonishing levels of radiation.
During 1949, the first full year of operation, workers at A Reactor received
an average dose of 93.6 rem -- three times the standards then set by the
ministry, where were too high to begin with: about 30 rem per year. (Standards
for nuclear work rs in Russia, as in the United States, are now about 5
rem per year, although they are about the be lowered in the United States
to 2 rem.) Workers were exposed to an average of 113.3 rem in 1951, and
a small percentage received more than 400 rem a nually during this early
period.
In 1951, radioactivity carried by the Techa River from Chelyabinsk-40 was
found in the Arctic Ocean -- although 99 percent of the radioactive material
was deposited within the first 35 kilometers downstream. This discovery
prompted a change in umping policy: The Techa and its floodlands were excluded
from human use, some inhabitants were evacuated, and others were supplied
with water from other sources.
Reservoirs were created to keep water from flowing out of the most contaminated
areas, and plant wastes were discharged into Karachay Lake, which has no
outlet, instead of into the river. The lake, actually a bog, eventually
accumulated 120 mil ion curies of the long-lived radionuclides cesium 137
and strontium 90. By comparison, the Chernobyl accident released one million
curies of cesium 137 and 220,000 curies of strontium 90. In 1967, wind
dispersed radioactivity from the lake, contam nating about 1,8000 square
kilometers. Today, radioactivity in the ground water has migrated two to
three kilometers from the lake. A person standing on the lake shore near
the area where wastes are discharged from the plant would receive about
60 roentgens of radiation, a lethal dose, in an hour. The lake is now being
filled with hollow concrete blocks, rock, and soil to reduce the dispersion
of radioactivity.
The Techa River was originally cordoned off with a wire fence and people
were forbidden to fish in it, or to pick mushrooms and berries or cut hay
nearby. Today, the shattered remains of the fence rust by the riverside
and regulations are widely ignored by the population. There are 400 million
cubic meters of radioactive water in open reservoirs along the river. Fish
in one reservoir are reported to be "100 times more radioactive than
normal."
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