Geological features and health problems
Naresh Kochhar
Environmental geology is an integrated application of geology for the benefit of man and his living and inanimate world. Geological features greatly influence man and his activities and the environmental geology embraces the whole gamut of human use of the earth — the prediction, assessment and combating of natural hazards, and the application of technology and engineering for the development of society without destroying environment.

UNDERSTANDING THE UNIVERSE
WITH PROF YASH PAL

Geological features and health problems
Naresh Kochhar

Environmental geology is an integrated application of geology for the benefit of man and his living and inanimate world. Geological features greatly influence man and his activities and the environmental geology embraces the whole gamut of human use of the earth — the prediction, assessment and combating of natural hazards, and the application of technology and engineering for the development of society without destroying environment.

The chemical quality of surface and groundwater is influenced by the local geology. Reactions between rain water and the bed rocks over a period of days and months as infiltrations and percolation occurs and are responsible for mineral content of groundwater.

The extent to which reaction with host rock proceeds will be governed by the residence time of the water, which in turn may be influenced by the type of flow movement i.e. intergranular of fissure flow movement and the mineralogy of the aquifer. The concentration of carbondioxide in the soil influences the degree of reaction of carbonates or silicates mineral in a rock. Deeper groundwater can undergo notable change in mineral composition increase of residence time.

In SW Punjab and the adjoining areas of Haryana, the basement rocks go down rapidly from Tusham to Bhatinda (Fig 2). East of Sirsa, rocks of Malani suite, granites and rhyolites and Delhi quartzites are encountered below the Quaternary sediments. At Zira, near Firozepur, granitic rocks are met at a depth of 700m below Siwalik sediments. At Adampur, the basement is encountered at a depth of 2500 m. The maximum depth to basement in Punjab plains is about 4 to 5 km and the depth increases to some extent under Siwaliks.

It is interesting to mention here that under a thick blanket of Quaternary sediments (305-350 m) in SW Punjab (Faridkot and Firozepur dists.) Haryana (Sirsa district) a thick sequence of halite (NaCl) and associate evaporites (polyhalite, anhydrite, limestone and dolomite) occur. Four cycles of evaporites with a cumulative thickness of 130.77 m occur under Punjab plains, and three cycles of evaporites (cumulative thickness of 50 m) occur under Haryana plains. The dolomites/limestone are of foetid character-they give sulphrous smell when stuck with hammer.

The subsurface geology under Punjab and Haryana plains has controlled the chemical quality and radon contest in groundwater.

Radon: Radon is a decay product of uranium and thorium. These elements are present in crust and granitic rocks.

Uranium decays to radium which in turn decays to radon. The radon gas is colorless, odourless and tasteless. It migrates through caves, ground fissures and buildings. The radon gas and its daughter products are known to cause cancer.

Survey of radon activity in groundwater done in collaboration with scientists of GND University, Amritsar, reveal that the values increase from Amritsar towards Bathinda and village in Haryana This is mainly due to the interaction of groundwater with the soils formed from the weathering of Malani granites exposed at Tusham and also at the basement. These granites have high concentration of U and Th. The concentration of radon in water varies from 2.28 to 7.96 Bq/l which are below the safe limits (400 Bq/L, Internationally recommended value). At Zira the value is 6.53, at Maur it is 7.90 and at Jajjal (Talwandi Saboo the concentration is 3.27 to 4.33). It is interesting to mention here that maximum number of cancer patients are reported from here.

Higher than desirable values of F, So₄, NO₃, Na and Mg have been reported for Jajjal, Kotshamir, Maur and Bhucho Khurd villages in Bathinda dist.

As per newspapers report (most recent HT, Dec 1, 2003)Jajjal and Giana villages to Talwandi Saboo block of Bhatinda dist. record the maximum number of cancer patients in the region.

About 70-80 persons have died due to cancer of different body parts since the seventies.

People attribute cancer cases to the groundwater quality which is brackish and fluoride rich. There does not seem be any correlation with quality of groundwater with the cancer, as many adjoining villages record higher concentration of these elements such as Maur Mandi, Nahinwala etc.

The high concentration of these elements can be attributed to the subsurface geology ie. granitic rocks and the presence of evaporires including limestone and dolomite which could contribute F, Ca, Mg, So4 etc.

It is interesting to mention here that the area falls within the cotton belt of Punjab and there is a widespread use of pesticides. Since there is no industry in Bhatinda dist. the carcinogenic elements such as cadmium, nickel, chromium, asbestos could not have contributed to the problem. PGIMER, Chandigarh is carrying out survey in the area.

Medical Geology: Medical geology is the science dealing with relationship between natural geological features and health problems in humans and animals.

It is broad and complex subject which requires interdisciplinary contributions from different scientific fields.

The writer is Professor, Centre of Advanced Study in Geology, Panjab University.

UNDERSTANDING THE UNIVERSE
WITH PROF YASH PAL

Water that comes to us after flowing through soil and crevices of land for a long time has dissolved in it salts of calcium and magnesium, besides other chemicals. If these salts are in reasonable quantity we treasure that water for drinking and call it mineral water. Such water is not injurious to health - perhaps just the reverse. But this water may not be very good for washing clothes, for being used in boilers, even for household plumbing. On drying it leaves hard deposits. When it interacts with soap it reduces its efficacy by reacting with the organic acid of the soap to form insoluble salts of calcium and magnesium. These salts form a grayish scum that covers the clothes and the cleaning action of soap is subverted. Such water is called hard water.

Passing hard water over resins that contain complex sodium salts can soften hard water. Calcium and magnesium are left on the resin surface while sodium goes into the water.

With the naked eye most stars look about the same colour, namely white. But you are right in guessing that they are not exactly the same colour if you analyse the light with spectrometers. There are several categories of stellar objects; how they shine primarily depends on their surface temperature. This temperature depends on their mass and their history. Massive stars produce energy at a much faster rate than does an average star like our sun. Therefore such stars are brighter.

(In all this discussion you must factor out the effect of distance. Stars that are further away would be fainter). As the stars develop their mode of energy production changes. This clearly affects their surface brightness. Some categories of stars are called red giants and others as white dwarfs. The last category belongs to those stars that have exhausted all their fuel, do not have a mass large enough to produce supernovae or neutron stars. They slowly cool down and their spectrum, or colour, shows the effect.

On the other end are stars in the process of formation, or those that are barely stars. They are cool and shine predominantly in infrared.

Echo is perceived when our sound comes back to us a little later. We feel that the environment repeats our shout. Concrete is a good reflector of sound. A sound made in an empty concrete room gets reflected several times and produces a reverberation. This can be reduced or eliminated if the walls are covered with sound absorbing material. This could be soft boards of various kind or just curtains on walls and carpets on the floor. You can of course fill up the room with people. Their bodies would also absorb the sound. For auditoriums and cinema halls a lot of attention is paid to ensure that while reverberations are minimised the hall does not become completely dead. Our ears like a small amount of sound reflection. That way music sounds fuller. But this has to be done carefully

If the sound is produced in the vehicle then he would be able to hear it without being aware that the vehicle itself is travelling fast. There might be vibrations in the inner structure of the vehicle. These also he would be able to hear. But he will not hear the sound of the exhaust or the sonic boom tailing the vehicle. Inside of a well-designed vehicle would be very quiet. Noise it makes it will tail it in a boom spreading along its path.

The detector in a microphone or the telephone mouthpiece senses sound vibrations the same way as any other object. It sets the diaphragm or the crystal face into vibration. The microphone or the mouthpiece converts this into electrical vibrations that are then sent to the receiving end where they might be recorded or converted into a sound wave by vibrating another diaphragm. Sound is not transmitted a long distance as vibration in air but through the mediation of a conducting cable or radio waves.

Put the inventor of the light-emitting diode and the maker of the world’s fastest transistor together in a research laboratory and what kinds of bright ideas might surface? One answer is a light-emitting transistor that could revolutionise the electronics industry.

Professors Nick Holonyak Jr and Milton Feng at the University of Illinois at Urbana-Champaign have uncovered a light-emitting transistor that could make the transistor the fundamental element in optoelectronics as well as in electronics. The scientists report their discovery in the Jan. 5 issue of the journal Applied Physics Letters.

"We have demonstrated light emission from the base layer of a heterojunction bipolar transistor, and showed that the light intensity can be controlled by varying the base current," said Holonyak, a John Bardeen Professor of Electrical and Computer Engineering and Physics at Illinois. Holonyak invented the first practical light-emitting diode and the first semiconductor laser to operate in the visible spectrum.

"This work is still in the early stage, so it is not yet possible to say what all the applications will be," Holonyak said.

"But a light-emitting transistor opens up a rich domain of integrated circuitry and high-speed signal processing that involves both electrical signals and optical signals".

A University of Florida-led team of astronomers may have discovered the brightest star yet observed in the universe, a fiery behemoth that could be as much as much as seven times brighter than the current record holder. But don’t expect to find the star — which is at least 5 million times brighter than the sun — in the night sky. Dust particles between earth and the star block out all of its visible light.

Whereas the sun is located only 8.3 light minutes from Earth, the bright star is 45,000 light years away, on the other side of the galaxy.

It is detectable only with instruments that measure infrared light, which has longer wavelengths that can better penetrate the dust.

In a National Science Foundation-funded study presented at the American Astronomical Society national conference in Atlanta, the team says the star is at least as bright as the Pistol Star, the current record holder, so named for the pistol-shaped nebula surrounding it.

Whereas the Pistol Star is between 5 million and 6 million times as bright as the sun, however, the new contender, LBV 1806-20, could be as much as 40 million times the sun’s brightness.

"We think we’ve found what may be the most massive and most luminous star ever discovered," said Steve Eikenberry, a UF professor of astronomy and the lead author of a paper on the discovery that was recently submitted to the Astrophysical Journal.