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Biomedical subjects

N Madhavan

Publications and source records attributed to N Madhavan.

5 recordsLinked to original sources
PubMed2005

Asbestos problem in India.

Primary exposure to asbestos in India can be encountered in the form of asbestos mining, asbestos cement industries, asbestos processing unit and during renovation and demolition of old asbestos cemented roof or other structures as well as modern electrical as well as mechanical appliances in which asbestos is still found. Ultimately construction workers, electricians, vehicle mechanics and other workers in the building trades who are exposed to asbestos inhale hundreds and thousands of amphiboles, which causes lung damage. It is being mined in India at places such as Andhra Pradesh (Pulivendla), Jharkand (Roro), Rajasthan (Ajmer, Bhilwara, Udaipur, Rajsamand) and the common problem faced by the locals are asbestosis through air and fluorosis through drinking water. The problem continues to be in India as well as other developing countries. Also, India import and re-export asbestos to other countries and workers at shipyard, transport of the hazardous material on road and roadside residents all are vulnerable to this uncommon disease. The signs and symptoms generally found with the workers are shortness of breath, persistent and productive cough due to pulmonary fibrosis can show up many years after the asbestos exposure.

Asbestos↗
PubMed2005

Oxidative and thermo-oxidative co-treatment with anaerobic digestion of excess municipal sludge.

The effect of oxidative and thermo-oxidative co-treatment of excess municipal sludge was investigated. A mixture of primary and waste activated sludge was anaerobically treated using two different configurations: i) two stages and ii) a single stage with recycling. Oxidative or thermo-oxidative co-treatment placed in between the reactor or in the recycle line was studied. A two-stage configuration with no co-treatment served as a control and resulted in 50.1% overall solids removal. Compared to the control, an increase in solids removal of 10.8 and 2.7% was observed when oxidative co-treatment was placed between reactors and in the recycle line respectively. When thermo-oxidative co-treatment was placed between the two stages or in the recycle line an increase in solids removal of 25.1 and 26.9% respectively was observed. The performances of the different configurations were also evaluated with parameters such as COD, TKN, ammonia, and fecal coliform concentration.

Bacteria, Anaerobic↗
PubMed2003

Nature of distribution of mercury in the sediments of the river Yamuna (tributary of the Ganges), India.

Suspended Particulate Matter (SPM), surface (bed sediments) and short length cores of sediments collected from the largest tributary of the river Ganges, namely the river Yamuna, were analysed for total mercury as well as its fractionation in various size and chemical sites in the sediments following standard procedures. Also, attempts were made to determine the vertical distribution in sediments in relation to the recent timescale of a few decades. Our observations indicate that the SPM in general showed higher levels of total mercury compared to the surface sediments while at places the enhancement could be by a factor of 10, say around 25 microg g(-1) in the downstream region that integrates the industrial midstream and agricultural downstream terrain near its confluence with the Ganges. Surface sediments in the upstream direction near the Himalayan foothills and SPM in the lower reaches showed significant high Index of Geoaccumulation (Igeo) as defined by Müller. Size fractionation studies indicate that the finer fraction preferentially showed higher levels of mercury while in the lower reaches of the river, the total mercury is equitably distributed among all size fractions. The proportion of the residual fraction of mercury in relation to mobile fractions, in general decreases downstream towards its confluence with the Ganges river. In sediment cores, the vertical distribution show systematic peaks of mercury indicating that addition of this toxic metal to the aquatic system is in direct proportion to the increase in various types of human activities such as thermal power plants, land use changes (urbanisation) in the midstream region and intensive fertiliser application in lower reaches of this vast river basin.

Agriculture↗
PubMed2002

Fluoride in fractionated soil samples of Ajmer district, Rajasthan.

The natural abundance of fluoride in soils of the Ajmer distict, Rajasthan was examined. From undisturbed soil, the top 15 cm of the profile was examined and the soil split into fractions based on sand, silt and clay particle size. Clay contained a high amount of fluoride, whereas sand and silts are enriched with much less fluoride. The relation between the soil fractions in observed clay fraction fluoride content matched groundwater fluoride variation. However, the enrichment of fluoride material extracted from the largest soil fraction had considerably lower amounts of clay relative to that from the smaller fractions.

Aluminum Silicates↗