There is less oxygen in your blood in mountain- says research

There is less oxygen in your blood in mountain- says research

by

Dr. Nitish Priyadarshi

Climbers summiting Mount Everest have as little oxygen in their bloodstream as residents of coastal areas who are in cardiac arrest- or who have even dead. Four physicians from University College London trekked up Everest and drew their own blood for analysis. They found that because of the altitude, they had about a quarter less oxygen in their blood than is normal for people at sea level. The analysis also confirmed other effects of being at high altitudes, such as the increase in hemoglobin to ferry as much oxygen as possible.

The number of people travelling to the high altitude regions, especially South America, Nepal, and India, has risen enormously in the past 10 years. Without special climbing ability these trekkers can be exposed to altitudes they will not have encountered in their home countries.

In India tourists traveling towards remote areas of Leh and Laddakh region of Jammu and Kashmir state complain of breathlessness and fatigue.

The concentration of oxygen at sea level is about 21% and the barometric pressure averages 760 mmHg. As altitude increases, the concentration remains the same but the number of oxygen molecules per breath is reduced. At 12,000 feet (3,658 meters) the barometric pressure is only 483 mmHg, so there are roughly 40% fewer oxygen molecules per breath. In order to properly oxygenate the body, your breathing rate (even while at rest) has to increase. This extra ventilation increases the oxygen content in the blood, but not to sea level concentrations. Since the amount of oxygen required for activity is the same, the body must adjust to having less oxygen. In addition, for reasons not entirely understood, high altitude and lower air pressure causes fluid to leak from the capillaries which can cause fluid build-up in both the lungs and the brain. Continuing to higher altitudes without proper acclimatization can lead to potentially serious, even life-threatening illnesses.

The major cause of altitude illnesses is going too high too fast. Given time, your body can adapt to the decrease in oxygen molecules at a specific altitude. This process is known as acclimatization and generally takes 1-3 days at that altitude.

Lack of oxygen causes high-altitude sickness. As altitude increases, the air becomes "thinner," which means less oxygen is in the atmosphere. You get less oxygen in your lungs with each breath, so the amount of oxygen in your blood declines. (This is called hypoxia). All people can experience mountain sickness, but it may be more severe in people who have heart or lung problems.

What are the symptoms?
Symptoms usually begin within 48 hours of arriving at high altitude. The higher the altitude, the greater the effects. People can notice effects when they go to an altitude of 7,000 to 8,000 feet. If you have heart disease (such as heart failure) or lung disease (such as emphysema), you may have symptoms at lower altitudes. Symptoms include headaches, breathlessness, fatigue, nausea or vomiting, inability to sleep swelling of the face, hands and feet.
Both heart rate and breathing rate increase as the body tries to send more oxygen to its tissues. At very high altitudes, body fluid can leak into the brain (called brain or cerebral edema) or into the lungs (pulmonary edema). Both these conditions can be serious or even life-threatening.

How can we prevent high-altitude illness?
You can do two important things to prevent high-altitude illness:

1. Take your time traveling to higher altitudes. When you travel to a high altitude, your body will begin adjusting right away to the lower amount of oxygen in the air, but it takes several days for your body to adjust completely. If you're healthy, you can probably safely go from sea level to an altitude of 8,000 feet in a few days. But when you reach an altitude above 8,000 feet, don't go up faster than 1,000 feet per day. The closer you live to sea level, the more time your body will need to get used to a high altitude. Plan your trip so your body has time to get used to the high altitude before you start your physical activity.

2. Sleep at an altitude that is lower than the altitude you are at during the day. For example, if you ski at an elevation of 10,000 feet during the day, sleep the night before and the night after at an elevation of 8,500 feet.

Reference:
L. Jordan, March 2009. Scientific American, India. pp.19
http://www.americanheart.org/presenter.jhtml?identifier=4618
http://www.princeton.edu/~oa/safety/altitude.html
http://familydoctor.org/online/famdocen/home/healthy/physical/injuries/247.html
http://findarticles.com/p/articles/mi_m0999/is_n7165_v317/ai_21250857

Threat of Nitrate to our environment and health.

Jharkhand and Bihar is coming under threat

by

Dr. Nitish Priyadarshi

Nitrate (NO3-) is a water-soluble molecule made up of nitrogen and oxygen. It is formed
when nitrogen from ammonia or other sources combines with oxygenated water.

Nitrogenous materials are rare in the geological record; therefore, occurrence of nitrate in groundwater is an anthropogenic pollutant contributed by nitrogenous fertilizers, industrial effluents, human and animal wastes through biochemical activity of nitrifying bacteria, such as nitrosomanas and nitrobacter. The groundwater resources contaminated with high level of nitrate (greater than 45 mg/l) are an environmental hazard. Nitrate has been linked to agricultural activities due to excessive use of nitrate fertilizers.

The nitrate is taken up by plants during their growth and used in the synthesis of organic nitrogenous compounds. Surplus nitrate readily moves with groundwater. Under aerobic conditions, it percolates in large quantities into the aquifer because of the small extent to which degradation or denitrification occurs. Under anaerobic conditions, nitrate may be denitrified or degraded almost completely to nitrogen.

In surface water, nitrification and denitrification may also occur, depending on the temperature and pH. The uptake of nitrate by plants, however, is responsible for most of the nitrate reduction in surface water.

Concentrations of nitrate in rainwater of up to 5 mg/litre have been observed in industrial areas. In rural areas, concentrations are somewhat lower.

Nitrogen compounds are formed in the air by lightning or discharged into it from industrial processes, motor vehicles, and intensive agriculture. These are removed by wet and dry deposition.

Air pollution appears to be a minor source. In general, vegetables will be the main source of nitrate intake when levels in drinking water are below 10 mg/litre. When levels in drinking water exceed 50 mg/litre, drinking water will be the major source of total nitrate intake, especially for bottle-fed infants. In the Netherlands, the average population exposure is approximately 140 mg of nitrate per day(including the nitrate in drinking water).

Vegetables and cured meat are in general the main sources of nitrate and nitrite in the diet, but small amounts may be present in fish and dairy products. Most vegetables and fruits contain 200-2500 mg of nitrate per kg. The nitrate content of vegetables can be affected by the processing of the food, the use of fertilizers, and growing conditions. Vegetables such as beetroot, lettuce, radish, and spinach often contain concentrations above 2500 mg/kg, especially when they are cultivated in greenhouse.

The nitrate concentration in surface water is normally low (0-18 mg/litre), but can reach high levels as a result of agricultural run-off, refuse dump runoff, or contamination with human or animal wastes. The concentration often fluctuates with season and may increase when the river is fed by nitrate-rich aquifers. Nitrate concentrations have gradually increased in many European countries in the last few decades and have sometimes doubled over the past 20 years. In the United Kingdom, for example, an average annual increase of 0.7 mg/litre has been observed in some rivers.
The natural nitrate concentration in groundwater under aerobic conditions is few milligrams per litre and depends strongly on soil type and on the geological situation. In the USA, naturally occurring levels do not exceed 4-9 mg/litre for nitrate.

Several researches in India have reported nitrate incidence of groundwater related to different sources, such as leaching of organic and inorganic fertilizers from agricultural land by infiltration and percolation of rainwater, irrigation water, animal waste, leakage from sewers and by subsurface flow from up gradient areas.

Somasundram et al. (1993) reported nitrate concentrations ranging from 12 to 999 mg/litre in Madras (now Chennai) urban area, and found that source of nitrate concentrations are due to sewage effluents. In Varanasi area of Uttar Pradesh in India, high nitrate concentrations are due to the direct leaching of domestic sewage effluents.

Nitrate is high in groundwater in some pockets of Jharkhand State. Concentration varies from less than one ppm to 100 ppm. In some parts of Godda the concentration level has reached up to 168ppm. In few parts of Sisai area, near the capital of Jharkhand State the concentration is above 100ppm.

Ranchi city is coming under the threat of nitrate poisoning as city is becoming the dumping ground of the municipal wastes and household wastes. At present the concentration of nitrate has reached threshold level in groundwater of Ranchi city but it may increase in summer season because low level of groundwater increases the concentration of metals.

The accumulation of high nitrate in cracks, fissures in the hard rocks of the Jharkhand State, is obvious due to the relatively thin soil cover and occurrence of groundwater at shallower depth, pollutants find their way to the groundwater body. Other than anthropogenic sources metamorphic rocks present in Jharkhand Plateau can be the other source of nitrate to ground water because nitrogen is found in the metamorphic rocks.

In Bihar State other than Rafiganj and Bhagalpur area concentration of nitrate in groundwater is below toxic level. In Rafiganj the concentration of nitrate varies from 100 ppm (parts per million) to 300ppm. Whereas in Bhagalpur it varies from 90 to 160 ppm. In some parts of Motihari district the concentration of nitrate has reached up to the level of 155 ppm. In Valmiki Nagar few places have been identified where the concentration of nitrate has crossed the toxic level.

Health Effects:

The primary health effect from high nitrate levels is methemoglobinemia which affects infants up to 6 months of age and can ultimately result in death. The condition is also called "blue baby syndrome" because the skin appears blue-gray or lavender in color. This color change is caused by a lack of oxygen in the blood. . Bacteria that live in the digestive tracts of newborn babies convert nitrate to nitrite (NO2). Nitrite then reacts with hemoglobin, which carries oxygen in blood, to form methemoglobin. Infants suffering from "blue baby syndrome" need immediate medical care because the condition can lead to coma and death if it is not treated promptly.
Within several months after birth, the increasing level of hydrochloric acid in a baby's stomach kills most of the bacteria which convert nitrate to nitrite. By the age of six months, the digestive system is fully developed, and the risk of nitrate-induced methemoglobinemia is greatly reduced.

Increased mortality rates are recorded from gastric and prostate cancer with increasing exposures to nitrates in the drinking water as found in Spain. A cluster of spontaneous abortions was identified in Indiana among women consuming nitrate contaminated well waters. Some scientific studies have found evidence suggesting that women who drink nitrate-contaminated water during pregnancy are more likely to have babies with birth defects. Nitrate ingested by the mother may also lower the amount of oxygen available to the fetus.

The toxicity of nitrate to humans is thought to be solely the consequence of its reduction to nitrite. The major biological effect of nitrite in humans is its involvement in the oxidation of normal haemoglobin to methaemoglobin, which is unable to transport oxygen to the tissues. The reduced oxygen transport becomes clinically manifest when methaemoglobin concentrations reach 10% of that of haemoglobin and above. The haemoglobin of young infants is more susceptible to methaemoglobin formation than that of older children and adults. Other groups especially susceptible to methaemoglobin formation include pregnant women and people deficient in glucose-6-phosphate dehydrogenase or methaemoglobin reductase.

People who have heart or lung disease, certain inherited enzyme defects, or cancer may be more sensitive to the toxic effects of nitrate than others. In addition, some experts believe that long-term ingestion of water high in nitrate may increase the risk of certain types of cancer.

References:
Grant, W., Steele, G., Isiorho, S.A. 1996. Spontaneous abortions possibly related to ingestion of nitrate-contaminated well water-LaGrange County, Indiana,1991-1994. Morb. Mortal Wkly Rep., v.45, pp 569-572.

Guidelines for drinking-water quality 1999. Health criteria and other supporting information. World Health Organization, Geneva, 2nd edition, v.2.


Raju, N.J., Prahlad, R.Dey,S. 2009. Groundwater quality in the Lower Varuna River Basin, Varanasi District, Uttar Pradesh. Jr. of Geological society of India, v.73 (2) pp. 178-192.

Somasundaram, M.V., Ravindran, G., Tellam, J.H. 1993. Groundwater pollution of the Madras urban aquifer, India. Groundwater,v.31 (1) pp 4-12.


http://dnr.wi.gov/org/water/dwg/nitrate.htm
http://www.bae.ncsu.edu/programs/extension/publicat/wqwm/ag473_4.html