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Biomedical subjects

K S Nambi

Publications and source records attributed to K S Nambi.

17 recordsLinked to original sources
PubMed1999

History of accumulation of mercury and nickel in Thane Creek, Mumbai, using 210Pb dating technique.

The study area Thane Creek, lies on the southern part of the Deccan belt of India between latitude 18 degrees 53'-19 degrees 04' N and longitude 72 degrees 48'-72 degrees 53' E and includes the Ulhas river estuaries. Lead-210 (half-life of 22.3 years) is used for an estimation of recent sedimentation rate in Thane Creek using radiochemical separation and alpha counting of its grand-daughter 210Po. The concentration of Hg and Ni in vertical depth profiles of sediment is estimated to assess the anthropogenic input of these nuclides due to large-scale industrialization which has taken place at this site during last two decades. Depth-wise concentration profiles of Hg and Ni indicate positive evidence of continued fresh inputs into the Airoli section of Thane Creek.

Fresh Water↗
PubMed1999

Assessment of Pb, Cd, Cu, and Zn exposures of 6- to 10-year-old children in Mumbai.

Population exposures to toxic trace metals are of great concern due to their nonbiodegradable nature and long biological half-lives for elimination from the body. Response to a toxic metal varies with age group; children are more sensitive and hence more at risk than others. The present study was therefore undertaken on 6- to 10-year-old children residing in various localities of Greater Mumbai and Thane. Blood samples from 566 children residing in 13 locations in Mumbai along with 410 air particulate samples and 64 "duplicate diet" samples were collected for this study. Levels of Pb, Cd, Cu, and Zn in these samples were estimated by differential pulse anodic stripping voltammetric technique. Intake of Pb, Cd, Cu, and Zn for 6- to 10-year-old children through ingestion and inhalation pathways have also been assessed. A correlation coefficient of 0.88 is observed between air lead and blood lead. It is also seen that every microgram increase in the Pb concentration in air (m-3) results in 3.56 microg increase in the blood Pb concentration (dl-1) in children. Similar correlation, however, was not observed in cases of Cd, Cu, and Zn.

Air↗
PubMed1999

Population study in the high natural background radiation area in Kerala, India.

A comprehensive survey of the population exposed to high-level natural radiation is presented. The population living in Karunagappally taluk in Kerala, India, presents a unique opportunity for studies on the health effects of chronic exposure to low-level radiation. The environmental radiation emanates largely from the thorium deposited mostly along coastal areas. In certain locations on the coast, it is as high as 70 mGy/year and on average is 7.5 times the level seen in interior areas. Using portable scintillometers, radiation levels in more than 66,306 houses were measured; outside levels were also measured in the same house compound. Of the total population of 400,000, 100,000 lived in areas with high natural radiation. Information on lifestyle, socio-demographic features, occupation, housing, residence history, and tobacco and alcohol use was obtained by house-to-house visits and enumeration of every resident individual. A population cancer registry system has been established to obtain cancer incidence rates. In this preliminary analysis, there is no evidence that cancer occurrence is consistently higher because of the levels of external gamma-radiation exposure in the area. Further dosimetry-level studies are needed along with biological studies. Studies of soil, thoron-in-breath, and the radon-thoron levels in houses are ongoing, and further case-control analyses are continuing.

Adolescent↗
PubMed1998

Lead leaching from pressure cookers.

Leachability of lead by tap water and tamarind solution from Indian pressure cookers while cooking with and without a safety valve is studied. Lead contamination of food by cookers is not very high when compared to the daily intake of lead from various food items consumed by the Indian community. However, looking at the very wide range of lead levels leached from various brands of pressure cookers, it certainly seems possible to keep the lead contamination to the minimum by proper choice of the materials used in the manufacture of these pressure cookers. The rubber gasket, which is a very important component of any pressure cooker, contains the maximum lead concentration; the safety valve is another important source leading to lead contamination of cooked food.

Cooking and Eating Utensils↗
PubMed1997

Retention times of Pb, Cd, Cu and Zn in children's blood.

Retention times of Pb, Cd, Cu and Zn in blood of 6- to 10-year-old children are estimated by measurements of levels of these metals in air particulate, duplicate diet and blood of 19 children residing in different locations in Mumbai (previously, Bombay) city. Retention times of 20.3, 9.1, 2.3 and 2.3 days for Pb, Cd, Cu and Zn, respectively are observed.

Air Pollutants↗
PubMed1997

Pooled analysis of cancer mortality cases among the employees in five units of the Department of Atomic Energy in India.

Available data on cancer mortality in the combined employee populations of five units of the Department of Atomic Energy, namely those in Mumbai, Tarapur, Kalpakkam, Hyderabad and Alwaye, with study periods ranging between 13 and 21 years, have been analysed. Data are available only on those still serving, i.e., subjects in the age group 20-59 yrs., and not on the retired employees and this is the major constraint in the study. A total of 81 cancer deaths have been recorded in the combined database of 316,619 Person-Years of which 28 (34.6% of the total) deaths belonged to the monitored Radiation Worker category having a database of 112,363 PY (35.5% of the total). Background age-specific cancer death rates of the urban Indian population have been constructed by averaging the only available age-specific cancer mortality data published by the Bombay Cancer Registry for Mumbai, Nagpur and Pune cities. Using this as a tentative "national urban baseline", the estimated Standardised Mortality Ratio for combined DAE employees works out to be 111 with 95% CI:80-138. The SMR for the Radiation Workers alone is 108 (95% CI:72-156) as compared to the SMR of 113 (95% CI:84-149) for the Non-Radiation Workers. The relative risk of radiation workers as opposed to non radiation workers is 0.96 (95% CI:0.64-1.39); analysis on individual types of cancer also leads to similar results. It is seen clearly that the radiation workers are not at any extra risk of cancer as compared to non-radiation workers. Nor does a comparison with the restricted national base-line data available for cities like Mumbai, Pune and Nagpur indicate any statistically significant risk of cancer in DAE populations.

Adult↗
PubMed1994

Database requirements for epidemiological estimates of radiation risks in continuously exposed populations.

Using the revised risk coefficients recommended by the 1990 report of the International Commission of Radiological Protection (ICRP), computations have been made on the minimum databases required for detecting radiogenic cancer excesses from epidemiological surveys of populations exposed to low level radiations. The computations have been made separately for Indian and Western populations using their representative demographic data. The western database requirements are generally found to be about half the Indian requirement. For the exposures in high background radiation areas at the rate of say 5 mSv/y, the minimum required database is 121,500 person years, in the Indian case. Similarly, for Indian occupational workers exposed at the rate of say, 10 mSv/y, it is required to observe 30,000 persons for the first 40 years or 3600 persons over their entire lifetime for obtaining statistically significant results.

Environmental Exposure↗
PubMed1991

A cancer mortality study in Bombay-based atomic energy community: 1975-1987.

Cancer deaths recorded by the centralised health services of the Department of Atomic Energy (DAE) among its employees and their families stationed in Bombay during 1975-1987 have been analysed. Expected number of deaths due to cancer in the study group has been estimated by using the age-sex-specific cancer death rates reported for Bombay resident population for the year 1983. The size of the database for the entire DAE community is about 702,000 person years and the number of cancer deaths observed in 154. Analysis has been done separately for employees and their families, individually for important groups of cancer sites such as respiratory organs, digestive organs, breast, genito-urinary organs and lymphatic and haematopoietic systems. The standardised mortality ratios are generally lower than 100, which may partly be due to the 'healthy worker effect' in the DAE community and partly because of its differences in the social class distribution and the concomitant differences in lifestyle with respect to the comparison group of Bombay city.

Adolescent↗
PubMed1987

Environmental radiation and cancer in India.

The hormesis hypothesis, which suggests that ecologically realistic low levels of ionising radiations may be beneficial to humans, seems to be substantiated significantly by the data available on cancer incidence/mortality rates and environmental radiation levels in various cities and states of India. Where the radiation level is greater, cancer risk is invariably less. The annual cancer incidence rate (per 100,000 population) seems to decrease by 0.03/microSv increase in the external background radiation dose from a hypothetical incidence level of 79 per 100,000 corresponding to "zero environmental radiation".

Background Radiation↗
PubMed1986

Gamma radiation dosimetry using a NaCl:Ba(T) thermoluminescent phosphor.

A detailed examination is presented of the thermoluminescence (TL) characteristics of untreated and heat-treated pure and Ba-doped NaCl exposed to gamma radiation at room temperature. The NaCl:Ba (10(-2) molar fraction) phosphor quenched from 750 degrees C, designated as NaCl:Ba(T), is found to give a pronounced TL output with a well-defined glow peak around 220 degrees C (peak III) along with other peaks at lower temperatures. It is suggested that the TL centre associated with glow peak III is comprised of an impurity-vacancy dipole with a negative ion vacancy in its vicinity. The TL centres are presumed to be located in the dislocation region. The dosimetric properties of peak III after gamma irradiation have also been examined. It is observed that most of the basic requirements of an efficient TLD material are fulfilled by the phosphor.

Barium↗
PubMed1982

Passive measurement of radon and thoron using TLD or SSNTD on electrets.

An electret is an electrical analogue of a permanent magnet and it carries a permanent electric charge. Our previous work has shown that such electrets are suitable for collecting decay products of radon and thoron in passive chambers. In the present work, the decay products are directly collected on the surface of a TLD or SSNTD providing in situ registration of the radiation from the decay products of radon and thoron. A 101. chamber, the sides of which were covered with a layer of Whatman No. 1 (W-1) filter paper, showed the following responses: (i) SSNTD (CR-39) recorded 92 +/- 13 tracks per cm2 per pCi/l, hr for radon and 9 +/- 1.5 tracks per cm2 per pCi/l. hr for thoron; (ii) for similar levels TLD (CaF2(Dy)) chips recorded an equivalent of 1.35 +/- 0.16 mR for radon and 0.30 +/- jk0.09 mR for thoron. Taking advantage of the differential response of the two chambers (one covered with a layer of W-1 filter paper and the other with a 75 mm polyurethene foam), simultaneous measurement of radon and thoron could be achieved.

Radiation Monitoring↗
PubMedDate not supplied

A study on cancer mortality in Tarapur-based atomic energy community.

Cancer mortality risks for individuals who were employed at nuclear facilities in Tarapur and for their respective family members with whom they lived were examined. Cancer deaths that occurred in this population between 1971 and 1988 were compared with death rates published by the Bombay City Cancer Registry. Risks were expressed as standardized mortality ratios (SMRs), which were computed by dividing the observed number of deaths by the expected number of deaths and multiplying this value times 100. There were 11 deaths from cancer among the employees, and this figure was too small to permit any trend analysis with respect to radiation exposures. The SMRs for all cancers and leukemia for male employees and for middle-aged male family members who were not exposed to any radiation were not statistically significant. A much larger database of person years at risk would be required to reach definite conclusions. The combined cancer risks for employees and families combined were similar to risks experienced by individuals in Bombay.

Adult↗