Hot Spots: Earth’s 5 Most Naturally Radioactive Places
By Steve, Web Ecoist, 22 January 2013.
By Steve, Web Ecoist, 22 January 2013.
While the news too-often tells of dangerous radiation from human sources, it bears reminding that the Earth itself is naturally radioactive…some places much more than others. Five natural radioactive “hot spots” stand out from all others, not just for their frighteningly high levels of radiation but also for the relatively good health of people who have lived there obliviously from time immemorial.
1. Guarapari, Brazil
Brazilian beaches may be famous for solar radiation (among other things) but strollers on Guarapari‘s pristine white sand shores may want to apply sunscreen to their soles as well. According to The National Centre for Biotechnology Information (NCBI), the sands of Atlantic coast beaches running from north of Rio de Janeiro down to south of Bahia (roughly 500 miles) are naturally radioactive. The source is sand eroded from Monazite, an ore of the naturally radioactive element thorium commonly found in mountains backing the shore.
Radiation levels are highest at Guarapari’s beaches, a popular seasonal tourist attraction, where readings of up to 175 mSv (millisieverts)) per year have been measured. Compare this figure with the current annual safe limit for nuclear workers: 20 mSv a year. Not coincidentally, Japanese government’s enforced 20 km exclusion zone around the stricken Fukushima Daiichi nuclear power plant is also rated at 20 mSv per year.
2. Ramsar, Iran
Think 175 mSv’s a walk in the park? We see your Guarapari and raise you a Ramsar - Ramsar, Iran to be exact. This city and county on the southern coast of the Caspian Sea is famous (or should we say, infamous) for having the highest levels of natural background radiation on Earth: 250 mSv per year! Background radiation levels up to 80 times the world average peak in the city’s Talesh Mahalleh district, where natural hot springs are abundant and limestone sourced from the area is used to make bricks and masonry used in area homes.
Image via: Taishitsu
Studies on the approximately 2,000 people living in the highest NBR areas show slightly lower rates of lung cancer - an unexpected result considering the elevated levels of radioactive radon gas in their homes. In addition, the population exhibits a significantly higher expression of the CD69 gene responsible for the production of lymphocytes (white blood cells in vertebrate immune systems) and natural killer (NK) cells. Ramsar, by the way, has been known from ancient times as a popular seaside vacation resort featuring medicinal hot springs - folk chemotherapy at its finest!
3. Paralana Hot Springs, Arkaroola, Australia
You’ll find the Paralana hot springs inside the Arkaroola Wilderness Sanctuary located in the arid northern Flinders ranges of South Australia but if you’re planning a hike in the area, bring your lead boots…and we don’t mean Led Boots on your MP3 player though a little Jeff Beck goes down easy just about anywhere. Subterranean springs flowing through uranium-rich rocks over 1 billion years old bring radioactive radon and uranium to the surface; hikers are well advised to refill their canteens somewhere else.
Image via: Liam.jon_d
Flickr user and photographer Liam.jon_d (Bill Doyle) has posted an exquisite set of images taken during a visit to the Paralana hot springs in April of 2011. That greenish glow you see isn’t what you might expect: it’s life, thriving between a rock and a hard (radiation) place! So-called “extremophile” blue-green algae flourish in the area’s hot springs, shrugging off water temperatures of up to 62 degrees centigrade heated not by geothermal energy but from radioactive decay.
4. Yangjiang, China
People living in the town of Yangjiang, located in China’s southern Guangdong province, have traditionally built their homes from bricks made of sand and clay. Trouble is, the sand in the region has eroded from hills containing monazite and once incorporated in bricks and mortar, thorium in the monazite sand continues to decay into radioactive radium, radon and actinium. It’s estimated that residents in the most highly affected areas of Yangjiang live with annual NBR exposures three times the world’s average.
Images via: Yangjiang China
A series of studies on people living in Yangjiang’s highest areas of natural background radiation dating back to 1970 indicated the mortality of residents from cancer was at or lower than that of residents in control groups living in areas with average exposure. Researchers believe that chronic exposure to higher than average radiation levels may have triggered an adaptive response mechanism that offers some protection from noted debilitating effects of radioactivity. The aforementioned info may or may not influence your decision to visit Yangjiang’s highly regarded hot springs resort.
5. Karunagappally, India
Karunagappally, a municipality in the Kollam district of Kerala, southwestern India, has been occupied since ancient times and as of the year 2001 had a population of approximately 610,000. Though today the region’s minerals are being exploited by rare earth metal mining operations, some of those minerals (monazite to be exact) have been eroding into beach sand and alluvial deposits for millions of years.
Images via: Bharatkalyan97
A 2009 study of background radiation and cancer incidence in Kerala conducted by the Regional Cancer Centre in Trivandrum, Kerala, India concluded that “In site-specific analysis, no cancer site was significantly related to cumulative radiation dose. Leukemia was not significantly related to HBR, either.”
Image via: Desdemona Despair
Are we right to panic over increases in radiation and radioactivity caused by nuclear accidents, wars, mining operations and more? Well, yes and no - though there’s no doubt that above “normal” levels of radioactivity can and do cause genetic damage and a wide range of cancers, it’s also safe to say that natural background radiation has been around since before the dawn of life on earth and, wonder of wonders, life goes on.
[Source: Web Ecoist. Edited.]