Wednesday, June 25, 2008
Tuesday, June 24, 2008
Dr. Nitish Priyadarshi
Owing to the record 338.1 mm rainfall on June 17 in Jharkhand State of India, maximum in the past six decades, radioactive wastes from the tailing pond of Turamdih uranium mines on the outskirts of the Jamshedpur city has reportedly spilled over into the village ponds, wells and fields.
According to the sources, the spill over was obvious due to torrential rain as there is no way to divert the water flowing into the village.
After the uranium ore is mined and processed here, the "yellow cake'" is sent to the Nuclear Fuel Complex in Hyderabad for enrichment. The waste is then brought back to the UCIL (Uranium Corporation of India Limited) complex for further extraction, after which the waste is dumped, into the ponds.
Apprehending threat to lives, the villagers have reportedly stopped fetching water from the wells and ponds.
The UCIL admitted the spill over but said there is no threat to life due to radiation.
A team of scientists from Bhabha Atomic Research Centre visited the affected village and collected water samples for analysis.
On December 24, 2006, one of the pipes carrying radioactive wastes from the uranium mill to a storage dam had burst, discharging highly toxic wastes into a nearby creek. The accident occurred in Dungridih a small village near Jadugoda inhabited largely by displaced families whose lands were acquired to construct two of the three storage dams, also known as tailings ponds. The tailings ponds store all the radioactive wastes generated by the milling of uranium ore in Jadugoda.
It is troubling that UCIL did not have its own alarm mechanism to alert the company in cases of such a disaster. Rather, the villagers that had arrived at the scene of the accident soon after the pipe burst informed the company of the toxic spill. Even more reprehensible is the fact that the toxic sludge spewed into creek for nine hours before the flow of the radioactive waste was shut off. Consequently, a thick layer of radioactive sludge along the surface of the creek killed scores of fish, frogs, and other riparian life.
The people in the Jadugoda area are affected not only by radiation from tailing dams but also by lack of safety at the mines. Fatigue, lack of appetite, respiratory ailments are wide spread. Increases in miscarriages, impotency, infant mortality, Down’s syndrome, skeletal deformities and different skin diseases, children with big heads, thalassemia have been reported. The incidence of tuberculosis among the miners is very high.One women of nearby Tilaitand village says that her husband deserted her because she could not get pregnant. Her villain: uranium mining. Other tribal women says her two children were born deformed at birth and were killed soon after. "The earth here is poisoned,'' she said.
Exposure to nuclear radiation is affecting the health of miners and villagers at Jadugoda in Singhbhum district in Jharkhand State located in Eastern India, which is India’s first uranium mining. Jadugoda, literally meaning "magic land", intrigues an outsider. The promise of magic enthralls; the mystery of the unknown attracts. But closeness reveals not innocence but an intention, dangerous and deliberate. According to different N.G.Os working among the tribal peoples of Singhbhum said the radiation may not bring sudden dramatic illness but slowly undermines the health of the people living in the surrounding villages.
The earliest reference to uranium mineral in India appeared in a German publication in 1860, in which Emil Stoehr recorded the occurrence of "Copper Uranite" at Lopso hill in Singhbhum. A huge tonnage of low-grade uranium ore rock is available which can yield 3000 to 4000 tonnes of uranium. At Jaduguda, the lodes are mainly confined to the conglomerates and granulated chlorite-quartz-tourmaline-magnetite rock. Workable deposits of uranium ore in this region have been proved up to 600 meters depth and the ore is being produced from this area.
Monday, June 23, 2008
Is Earth part of our solar system ?
Dr. Nitish Priyadarshi
From early age my mind always boggled at the mysteries of our solar system and the Sun. How they originated, how they are formed and how do they look . All these questions always puzzled me. Ideas about the formation of the Earth and our place in the universe often begin with star gazing. We ask more, and we learn more.
When I started studying geology I came to know that our mother earth is member of the solar system. All the principal theories which have been advanced to explain the origin of the earth, have in common the idea that the planets evolved from the sun. Regarding the origin of earth a number of theories have been put forward but none of them can be said to be perfectly correct.
The planets in our solar system comprises two sets. The inner terrestrial or rocky planets include, from sun out, moonlike Mercury, torrid Venus with its carbon dioxide green house and sulphuric acid clouds, Earth with cool blue seas and multicolored lands, ice capped Mars with long dry rivers and giant extinct volcanoes, and the frigid and commonly carbonaceous asteroids. The outer Jovian or ice-gassy planets are hydrogen-rich Jupiter with sulfurous plus a dozen icy satellites, gassy Saturn with its equally icy satellites and prominent rings, and the three less well known outermost planets.
How then, and when, did so diverse a collection of planets come to be as they are? Over the centuries that humankind has pondered such questions, different hypotheses have been advanced or modified.
It is commonly believed that the earth evolved with other members of the solar system . It means that earth and the other planets revolving round the Sun should have similarities in physical and chemical properties.
But to my great surprise the fact is opposite. When I went through the information about the other planets, I found out that there is a great difference between the earth and the other planets and Sun. There are some similarities between the other planets e.g. Saturn and Jupiter but our earth is totally different either in geology and geochemistry or in composition of gases from other planets.
Recently Pluto has been voted off the island. The distant, ice-covered world is no longer a true planet. According to the new definition, a full-fledged planet is an object that orbits the sun and is large enough to have become round due to the force of its own gravity. In addition, a planet has to dominate the neighborhood around its orbit.
Pluto has been demoted because it does not dominate its neighborhood. Charon, its large "moon," is only about half the size of Pluto, while all the true planets are far larger than their moons.
If you closely view our solar system you will find that our earth looks totally different from other planets. As if it is a foreign member intruded in solar system or been trapped in between the solar system. Our Earth is full of life and water. Prominent gases are Nitrogen and oxygen. It is active planet. If you put these definitions on other planets the answer is totally opposite. If we consider about the new definition of the planet, other than it orbits the sun and is large enough to have become round due the force of its own gravity and dominate its neighborhood, earth has no other similarity with other planets.
Earth’s ocean and atmosphere have evolved throughout the history of the planet, and continue to change today. Their original source and composition are not yet clearly identified. Compositional characteristics, such as less than solar proportions of the inert gases neon, krypton, and xenon, indicate that our atmosphere did not develop directly from nebular gas.
- Major gases on the Sun, Jupiter, Saturn and Uranus are hydrogen and helium, Mercury has helium and carbon dioxide, Mars atmosphere is composed of carbon dioxide. Whereas Earth has 77% nitrogen and 21% oxygen with traces of carbon dioxide. If earth has been borne from the same source and at same time there must be similarities in composition of the gases, which is not here.
- Early speculation proposed that the Moon broke off from the Earth's crust because of centrifugal forces, leaving a basin – presumed to be the Pacific Ocean – behind as a scar. The prevailing hypothesis today is that the Earth–Moon system formed as a result of a giant impact. A Mars-sized body (labelled "Theia") is believed to have hit the proto-Earth, blasting sufficient material into orbit around the proto-Earth to form the Moon through accretion. But Moon is very much different as it has no atmosphere and no magnetic field as compared to earth. Also the density of the Moon is much less than that of the Earth indicating that the Moon has comparatively less Iron and Nickel than the Earth. Although the lunar rocks bear many similarities to rocks common on Earth, they differ on one basic point – they contain no water, no hydrated minerals, and no minerals with the OH group in their crystal structure . In contrast, minerals that are hydrated or contain the OH group are plentiful on Earth. So where did the Moon come from? There is no clear answer to this question, in spite of all explorations and analyses.
- There is no geological movements on the other planets as compared to earth were geological movements in the form of plate tectonics is prominent.
- Heavy noble gases (xenon, neon, Krypton) are rare on earth as compared to space and the sun.
- Even the intensity of the magnetic field from planet to planet varies dramatically. Again I will say if the all the planets have the same origin there must have some similarities in the strength of the magnetic field which is not here.
- It is commonly said that Venus is very similar to earth. But it is composed mostly of carbon dioxide compared to Earth which is mostly composed of nitrogen and oxygen with trace of carbon dioxide. Scientists say that there was probably a very much larger amount of carbon dioxide in the earth’s atmosphere when the earth was first formed, but it has since been almost all incorporated into carbonate rocks. Why this phenomenon happened only on Earth and not on Venus. Also Venus has no magnetic field. Venus’ sky is red because carbon dioxide scatters red light. The sun appears bluish because of loss of the red component. There is no liquid water on Venus and therefore no life. The rotation of Venus is slower than its revolution making the rotation of Venus retrograde. As a result, the atmospheric circulation is totally different from that on Earth.
- Earth is the only planet which has developed complicated life structure. If Earth is part of the same source from which other planets have originated there should have been life on other planets too which unfortunately is not there. Why is it so? Why only earth was selected for the complicated evolution of life?
Some of my friends suggested me that Earth's uniqueness and especially its complex life and atmosphere comes from its location in the solar system which is neither too hot (as in Venus) or too cold (as in Mars and beyond). Again I will say if life would have been there on Mars or Venus they would have adapted accordingly to the earlier atmosphere on these planets as it adapted earlier on the Earth. In our Earth too there are extremes of climates from too hot to cold and the life is surviving here.
- The earth and other planets and sun each have a somewhat different density suggesting different time and/or temperatures of origin.
- Research comparing silicon samples from Earth, meteorites and planetary materials, published in Nature (28th June 2007), provides new evidence that the Earth`s core formed under very different conditions from those that existed on Mars.
- The giant planets Jupiter and Saturn, essentially of solar composition, are the gasiest. Their satellites and the comets are the iciest.
- How it happens that some planets and satellites have retrograde rotations ( rotate clockwise instead of counterclockwise like the others).
It seems that either Earth originated elsewhere and later became the part of the Solar System. If it has been originated from the same source it must be either younger or older to the other planets. If it is younger then we will have to believe the mythical or religious concept on the origin of the earth. The first recorded biblically estimate of the age of the earth (and universe) was made by Saint Augustine in the fourth century A.D. He counted about 6,000 years from biblical genealogies. Johannes Kepler, then professor of mathematics at Graz, calculated the date of creation to have been 3877 B.C., Sunday, 27 April, at 11 A.M. local time.
All the other planets are devoid of any types of life. Can it be possible that earlier life was there in some of these planets like Mars or Venus and due to effect of climate changes or some other factors life ended on these planets and our planet which I assume is younger to them may face the same fate in coming future. If we assume that Earth is older to the other planets then these planets may in future become like earth.
All ideas concerning the origin of the Earth and the solar system have their problems, and new discoveries often add to the demerits to the theories. All the theories regarding origin of Earth and Solar System are belief systems. Neither one can be proven because no one was there to witness the event, and it can not be repeated. Thus, the origin of the solar system continues to be a problem and even the most modern theories contain many points that need verification.
Friday, June 6, 2008
Dr. Nitish Priyadarshi
The weather gods, it seems, have crushed Jharkhand. If heat stroke was not enough, then lightning has emerged as a big killer as in the state. More than 200 people were killed because of lightning strikes in 2007. One incident occurred in the school premises near Ranchi city where six children were killed due to lightning. This year the toll is already more than 20.
In last two days seven people died due to lightning in Dumka and Jamshedpur district.
While the state government is perturbed, people get mortally scared when discharged electricity. Unlike heat waves which is more severe during summer, lightning strikes have taken place at alarming regularity in almost all parts of the state.
Mainly high elevated places are prone to lightning in Jharkhand. The plateau region of Jharkhand contains high amount of Iron stone in the rocks and soils. According to the recent studies lightning has been used as a naturally occurring instrument for studying the electrical nature of the ground. There have been numerous ancient observations based on these studies, however “few modern studies exist to indicate that soils of high conductivity (e.g. marshes) are lightning-prone; that ironstone outcrops attract lightning.
In Jharkhand forest areas are more prone to lightning. Trees are frequent conductors of lightning to the ground. Since sap is a poor conductor, its electrical resistance causes it to be heated explosively into steam, which blows off the bark outside the lightning's path.
From past several years the climate of Jharkhand has changed a lot from bad to worse. Ranchi which was earlier the summer capital of the Bihar and Jharkhand state united, is now under the impact of global warming or say regional warming. One of the major cause of global warming is carbon dioxide (CO2) emissions. Models have been developed that predict atmospheric increases in CO2. One such model predicts that a doubling of CO2could increase the amount of lightning occurrences by 30–77% .
The number of lightning deaths in the state has almost doubled in the past several years. Add to this the hundreds who sustain injuries and the loss of cattle and property annually. And, you would know why panic sets in when people in Jharkhand see the magnificent flashes with thundering sounds on the sky.
As floods ,earthquakes, cyclone, drought, hailstorms, tsunami figure in the list of natural calamities in India, lightning should also be included in the list.
Thursday, June 5, 2008
शनि ग्रह - धार्मिक एवं वेज्ञानिक दृष्टिकोण से
- डा नीतिश प्रियदर्शी
शनि ग्रह का नाम आते ही लोगों में भय व्याप्त हो जाता है। इसके प्रभाव को आज भारत के सभी न्यूज़ चैनल प्रमुखता से दिखा रहें हैं। प्राचीन काल से ही शनि ग्रह के बारे मैं विभिन्न विचार रखे गएँ हैं। हिंदू धर्मं मैं शनि ग्रह के बारे मैं बहुत कुछ लिखा गया है ।
शनि सूरज से ६ वें स्थान पर हैं और पूरे ब्रह्माण्ड में बृहस्पति के बाद सबसे विशाल ग्रह है । कहने को तो बृहस्पति सबसे विशाल ग्रह है लेकिन शनि ग्रह के पास सबसे ज्यादा उपग्रह है । इसके उपग्रहों की संख्या ५० से भी अधिक है यानि इस मामले मैं शक्तिशाली है।
धर्मं मैं अपने मंद गति से चलने के कारन इसका नाम "शनेचर" रखा गया। आधुनिक विज्ञान मैं भी यह मान्यता है की सूर्य से दूर होने के कारन यह सूर्य की परिक्रमा करने मैं काफी वक्त लगता है। इसका परिक्रमा पथ लगभग १४ करोड़ २९ लाख किलोमीटर लंबा है तथा सूर्य की एक परिक्रमा करने में इसे २९ १/२ वर्ष लगते हैं।
बृहस्पति की तरह शनि भी ७५ प्रतिशत हाइड्रोजन और २५ प्रतिशत हीलीयम से बना है।
धर्मं मैं शनि को सूर्यपुत्र माना गया है। इसका अर्थ है सूर्य से उत्पत्ति। यदि विज्ञान के नजर से देखा जाए तो शनि ही क्यों सभी ग्रहों की उत्पत्ति सूर्य से हुई है। ज्योतिष में शनि को सूर्य का शत्रु माना गया है शायद इसलिये, की अन्तरिक्ष मैं यह सूर्य से से काफी दूर है । शनि को प्रसन्न करने के लिये लोग नीले रंग का पत्थर (नीलम ) धारण करतें हैं। शनि ग्रह के रंग को अगर देखा जाए तो यह कभी हल्का हरा , पीला या नीला रंग देता है। इसका उत्तरी ध्रुव का रंग काफी नीला है।
ज्योतिष विद्या के अनुसार जो लोग शनि के कुप्रभाव में हैं उन्हें शनि के मन्दिर में तेल दान करने की सलाह दी जाती है। तेल की किल्लत से जहाँ पृथ्वी वासी परेशां हैं वहीं शनि के उपग्रह Titan पर तेल की बारिश हो रही है। नासा द्वारा शनि अभियान पर भेजे गए अंतरिक्ष यान "केसिनी " से मिले ताजा जानकारी के अनुसार Titan पर तरल हाइड्रोकार्बन के इतने अकूत भंडार मौजूद हैं की जितने पृथ्वी पर भी नहीं मिलते। तेल की बारिश के चलते यहाँ हाइड्रोकार्बन एवं मिथेन प्रचुर मात्र में जमा हो चुके हैं।
तो क्या प्राचीन लोगों को इसके बारे में जानकारी थी?
शनि से प्रभावित लोगों को अंगुली में लोहे का छल्ला धारण करने को कहा जाता हैं। इसमे भी कुछ समानता दिखती है। शनि ग्रह के चारों और कई छल्ले हैं। यह छल्ले बहुत पतले हैं एवं इसकी मोटाई एक किलोमीटर से भी कम हैं। इन छल्लो के कण मुख्यता बर्फ एवं बर्फ से ढंके पथरीले पदार्थों से बने हैं। शायद इसी संरचना को देखते हुए लोगों को लोहे का छल्ला अंगुली में धारण करने के लिये राय दी गई ।
शनि ग्रह के बारे में एक रोचक जानकारी यह हैं की इतना विशाल होने के बावजूद यह ग्रह घनत्व के मामले में पानी से भी कम हैं यानि काफी हल्का।
इन सारे तथ्यों पर यदीं हम ध्यान दें तो लगता हैं की प्राचीन काल में लोग भी अंतरिक्ष एवं शनि ग्रह के बारे में अच्छी जानकारी रखते थे ।
Tuesday, June 3, 2008
Dr. Nitish Priyadarshi
A mother elephant, and one-and-a-half-years-old calf died early morning on 2nd June after being electrocuted at Gerua village near Jamshedpur city in India. The pachyderms died after coming in contact with live electric wires that were passing about 7ft above the ground. Villagers had drawn a long wire from from an electric pole by erecting a bamboo pole to get electricity in their houses. As these wires were hanging at a height of 7 feet with the support of the bamboo, the calf elephant came in the contact with the wire when one of the bamboo trunks fell.
Elephants cross this area on a regular basis and the low lying wire caused the trouble. This is a regular phenomenon.
Incidents of elephants falling prey to electrocution have been reported from Koderma and Seraikela district of Jharkhand state.
The animals died on the spot. The shock resulted in the immediate cardiac and brain failure, said an expert.
The elephants were moving in herd in the sanctuary when a high tension carrying 1100 VA power fell on the two elephants. Both elephants died on the spot. In Jharkhand More than 11 elephants have been electrocuted to death in last seven years. The forest officials blame the low height of the electric wires passing through forest areas. The wires get in touch with tree and get broken and fell on the wild animals causing their death.
Recently a wild elephant named Osama Bin Laden has been shot dead in Jharkhand state, after killing more than eleven people.
According to forest officials the killed tusker has trampled to death to 11 people injured 22 in last two months. The same tusker had killed six people in Purulia district of West Bengal on May 21.
It had been terrorising villagers in two states, and had destroyed crops and homes.
Forest officials and a police team tracked the creature down in the state and said it took 20 bullets to silence him.
With paddy crop being ready for harvest in Jharkhand, the farmers of Ramgarh District of Jharkhand are a worried lot. They fear arrival of elephants from the nearby forests trespassing into the fields for food.
At times, the elephants cause havoc. Farmers lament the loss of crops worth lakhs of rupees as rampaging elephants destroy the fruit of their hard work.
Many people have been trampled to death and dozens of houses destroyed by elephants in the villages lining the forest land in recent months. Villagers shirk from moving around freely.
“These elephants have become a real menace now. They kill our folk, they hurt us, damage our crops. In one incident where this elephant dragged a man out of his house and killed him. The government hardly do anything. They do compensate the families immediately after the event but that’s it,” said a local villager.
During the season when paddy fields have standing crops, elephants attack villages and the surroundings to feast on the paddy. Incidences of man-animal encounter have increased over the past few years with forests areas fast depleting and animals looking for food stray into the human territory. Due to this conflict many people have lost their lives.
As larger patches of forest have disappeared from the state. Elephants need massive tracts of land because, much like the slash-and-burn farmers, they are used to crashing through the forest, tearing down trees and shrubs for food and then cycling back later on, when the area has re-grown. As forests are reduced to small pockets, elephants become part of the problem, quickly destroying all the vegetation in an area, eliminating all their resources.
Conflict over resources and access to land increases between elephants and humans as settlements develop around permanent water sources. In Jharkhand the elephants visit human settlement in search of alcohol which is locally made of Mahua tree (Madhuca longfolia ).
In Jharkhand the population of elephants have declined. The elephants population declined to 622 from 772 in the current census. The current census was conducted in May this year.
Sunday, June 1, 2008
Dr. Nitish Priyadarshi
Fig: 16 years old girl suffering from arsenic toxicity. This girl belongs to Sahebgunj district of Jharkhand. She is not able to walk properly due to pain in her feet. Her parents are worried about her marriage.
Fig: Man showing arsenic affected areas of his body.
- INTRODUCTION AND DISCUSSION:
Arsenic contamination of groundwater has led to a massive epidemic of arsenic poisoning in Bangladesh and West Bengal in India and neighbouring countries. It is estimated that approximately 57 million people are drinking groundwater with arsenic concentrations elevated above the World Health Organization's standard of 10 parts per billion. The arsenic in the groundwater is of natural origin, and is released from the sediment into the groundwater due to the anoxic conditions of the subsurface. This groundwater began to be used after western NGOs instigated a massive tube well drinking-water program in the late twentieth century. This program was designed to prevent drinking of bacterially contaminated surface waters, but failed to test for arsenic in the groundwater. Many other countries and districts in South East Asia, such as Vietnam, Cambodia, and Tibet, China, are thought to have geological environments similarly conducive to generation of high-arsenic groundwaters. Arsenicosis was reported in Nakhon Si Thammarat, Thailand in 1987, and the dissolved arsenic in the Chao Phraya River is suspected of containing high levels of naturally occurring arsenic, but has not been a public health problem due to the use of bottled water.
An environmental health disaster is unfolding in West Bengal and Bangladesh. Tens of millions of persons in many districts are drinking ground water with arsenic concentrations far above acceptable levels. Thousands of people have already been diagnosed with poisoning symptoms, even though much of the at-risk population has not yet been assessed for arsenic-related health problems. Alarming level of arsenic in the groundwater of eight districts of West Bengal and 2 districts of Jharkhand in East India has become a serious health hazard. The number of people suffering from skin lesions, muscular disorder and even cancer, is constantly going up. This is an acute 'environmental health' problem since the rural population in these districts is solely dependent on groundwater for drinking, bathing and cooking.
The source of the problem is geological in origin, which has aggravated due to excessive withdrawal of groundwater for paddy cultivation in the wake of the green revolution of the 1970s.
ARSENIC IN JHARKHAND
A detailed study has been presented on groundwater metal contents of Sahebgunj district in the state of Jharkhand, India with special reference to arsenic. Both tubewell and well waters have been studied separately with greater emphasis on tubewell waters. Groundwaters of all the nine blocks of Sahebgunj district have been surveyed for iron, manganese, calcium, magnesium, copper and zinc in addition to arsenic. Groundwaters of three blocks of Sahebgunj, namely, Sahebgunj, Rajmahal and Udhawa have been found to be alarmingly contaminated with arsenic present at or above 10 ppb.
Rivers flowing through the coal fields of Jharkhand have been reported to carry arsenic responsible for arsenic poisoning in downstream areas of West Bengal. The coal fields of Bachara and Piprawar areas of Jharkhand have contaminated the waters of the Damodar and its tributary, the Safi, causing problems in West Bengal. According to Nitish Priyadarshi, arsenic contamination arises mainly due to the dumping of waste from the coal mines along the river bed. Coals of the area mentioned contains sufficient amount of arsenic as described below.
Distribution of Arsenic in the water and in the Permian coals of North Karanpura Coalfield of Jharkhand State of India:
The North Karanpura coalfield, a western most member in the east-west chain of the Damodar Valley Basin, forms a large expanse of coal bearing sediments spread over Hazaribag, Ranchi and Palamau districts of Jharkhand State. It covers a total area of around 1230sq. Km. For the arsenic study, samples from coal from Badam, Kerendari, KDH, Rohini, Dakra and Karkatta were analysed by the author. Molybdenum-blue Colorimetry was used as the chemical technique for arsenic determination as recommended by the International Standard Organisation. Concentration of arsenic in coal samples range from 0.01 to 0.49ppm with an arithmetic mean of 0.15ppm. (Priyadarshi, 2004). Concentration of arsenic is low compared to most world coals. Average ash% is very high (up to 32.51%).
To understand the environmental impact of arsenic in coals of research area, water and sediments were analysed for arsenic concentration. Concentration were moderately high (2 ppm) in the sediments of local streams flowing through the coal mining area. Average concentration of arsenic in the sediments of mine water was 1.4 ppm. Though the concentration of arsenic is low in the surface water ( 0.001-0.002 ppm) it may still affect the local habitants especially during summer season when the consumption of water increases many folds. People of this area is consuming water from several years. Effects of arsenic will be there if the people of the area consume water containing arsenic for longer periods.
Real truth is that people of the area are ignorant about this toxicity. Few people know about this but due to lack of pure source of water they are helpless and are forced to depend on the contaminated water.
Local communities of the Sahebgunj district in the state of Jharkhand, are already showing sign of arsenic toxicity. Sufferers are complaining about body ache, skin problems, nausea etc.
General Source of arsenic
Arsenic is widely distributed throughout the earth's crust.
Arsenic is introduced into water through the dissolution of minerals and ores, and concentrations in groundwater in some areas are elevated as a result of erosion from local rocks.
Industrial effluents also contribute arsenic to water in some areas.
Arsenic is also used commercially e.g. in alloying agents and wood preservatives.
Combustion of fossil fuels is a source of arsenic in the environment through disperse atmospheric deposition.
Inorganic arsenic can occur in the environment in several forms but in natural waters, and thus in drinking-water, it is mostly found as trivalent arsenite (As(III)) or pentavalent arsenate (As (V)). Organic arsenic species, abundant in seafood, are very much less harmful to health, and are readily eliminated by the body.
Drinking-water poses the greatest threat to public health from arsenic. Exposure at work and mining and industrial emissions may also be significant locally.
Chronic arsenic poisoning, as occurs after long-term exposure through drinking- water is very different to acute poisoning. Immediate symptoms on an acute poisoning typically include vomiting, oesophageal and abdominal pain, and bloody "rice water" diarrhoea. Chelation therapy may be effective in acute poisoning but should not be used against long-term poisoning.
The symptoms and signs that arsenic causes, appear to differ between individuals, population groups and geographic areas. Thus, there is no universal definition of the disease caused by arsenic. This complicates the assessment of the burden on health of arsenic. Similarly, there is no method to identify those cases of internal cancer that were caused by arsenic from cancers induced by other factors.
Long-term exposure to arsenic via drinking-water causes cancer of the skin, lungs, urinary bladder, and kidney, as well as other skin changes such as pigmentation changes and thickening (hyperkeratosis).
Increased risks of lung and bladder cancer and of arsenic-associated skin lesions have been observed at drinking-water arsenic concentrations of less than 0.05 mg/L.
Absorption of arsenic through the skin is minimal and thus hand-washing, bathing, laundry, etc. with water containing arsenic do not pose human health risk.
Following long-term exposure, the first changes are usually observed in the skin: pigmentation changes, and then hyperkeratosis. Cancer is a late phenomenon, and usually takes more than 10 years to develop.
The relationship between arsenic exposure and other health effects is not clear-cut. For example, some studies have reported hypertensive and cardiovascular disease, diabetes and reproductive effects.
Exposure to arsenic via drinking-water has been shown to cause a severe disease of blood vessels leading to gangrene in China (Province of Taiwan), known as 'black foot disease'. This disease has not been observed in other parts of the world, and it is possible that malnutrition contributes to its development. However, studies in several countries have demonstrated that arsenic causes other, less severe forms of peripheral vascular disease.
According to some estimates, arsenic in drinking-water will cause 200,000 -- 270,000 deaths from cancer in Bangladesh alone.
Priyadarshi, N.: Arsenic in Damodar poisoning West Bengal. Indian Express, July 12, 1998.
Priyadarshi, N. 2004. Distribution of arsenic in Permian Coals of North Karanpura coalfield, Jharkhand. Jour. Geol. Soc. India, 63, 533-536.
Dr. Nitish Priyadarshi
Geologist and Lecturer
Department of Environment and Water Management,