S.K. Kashyap

Characterization and problems of indoor pollution due to cooking stove smoke

Findings from the five groups of matched houses, each using either cattle dung, wood, coal, kerosene or liquid petroleum gas (LPG) as cooking fuels are presented with emphasis on cross comparison of indoor pollution levels during the cooking period. The houses using LPG were considered as controls. The characterization of pollution was made by measurements of total suspended particulates (TSP), carbon monoxide, nitrogen dioxide, formaldehyde, sulfur dioxide and particle sizing of TSP, which were further analysed for the evaluation of levels of polycyclic aromatic hydrocarbons (PAHs). A correlation between the pollutants as a function of fuel type has also been looked for. The study revealed that 50–80% of the TSP emissions from biomass and coal-burning cooking stoves were in a respirable fraction of ≤2 μm size and that a large amount of the PAHs (> 75%) belonged to this fraction only. Air quality biomass-using houses was the worst among the users of the five aforementioned fuels and levels were relatively high. The findings stress that a conserted effort towards a solution should be made as a large fraction of the worlds population regularly uses biomass as a prime domestic fuel. The problems associated with cooking stoves in India and immediate research needs are outlined.

Levels of organochlorine insecticides in human blood from Ahmedabad (rural), India

Assessments of human exposure to persistent organochlorine insecticides (OCI) through biological monitoring offers a profound criteria to evaluate the magnitude of potential health risk, if any, due to use of these chemicals. Residues of these chemicals especially DDT and HCH have been identified and reviewed in man and his environment from different parts of the world however, by comparison very high levels of DDT and its metabolites have been reported in human body fat, blood and milk samples in India. Since there is a definite relationship between the amount of DDT and its residues in blood and those present in human fat depot, blood can be easily be used for assessing the total body burden of persistent OCI in various populations. In view of fragmentary reports on the levels of DDT and HCH in human blood samples from India which categorically pertain to the general population of urban areas like Delhi and Lucknow. The authors attempted to provide a database on residues of DDT and HCH including other cyclodiene compounds, e.g. heptachlor, heptachlor epoxide, aldrin, oxygchlordane, HCB and dieldrin in blood samples collected from general population of Ahmedabad (rural) area.

Carcinogenicity of hexachlorocyclohexane (BHC) in pure inbred swiss mice.

Inbred Swiss mice were treated with technical BHC (1) orally with the diet or by intubation and (2) by skin painting. The total duration of the experiment was 80 weeks. There was no difference in body growth and mortality between the experimental and control groups. Symptoms of intoxication in the form of convulsions and tendency of circling in one direction with drooping ears were observed alongwith corneal opacity 40 weeks after the experiment. Oral BHC treatment resulted in a significant increase in the incidence of liver tumours and tumours of lymphoreticular tissue. Males and females were equally susceptible. Skin painting of mice did not significantly increase the incidence of tumour.

Residues of organochlorine pesticides and polycyclic aromatic hydrocarbons in drinking water of Ahmedabad City, India

The ubiquitous environmental pollutants organochlorine pesticides (OCP) and polycyclic aromatic hydrocarbons (PAH) have been extensively studied for their toxicity. Monitoring of OCP and PAH residues has always been considered important for controlling human exposure. As compared to several other countries, the higher body burden of OCP in Indian general population is indicative of higher exposure to these chemicals. Recent studies have shown higher residues of OCP in food commodities including human mothers milk. The levels of OCP in drinking water is still a matter of concern and practically nothing is known about the residues of PAH in drinking water in India. This is the first report of its kind regarding the residues of OCP and PAH in drinking water of Ahmedabad City, the sixth largest city of India with a population of more than 2.5 million.

Cardiac Toxicity Following Short-Term Exposure to Methomyl in Spraymen and Rabbits

A health surveillance study in 22 healthy spraymen showed significent T-wave changes (including inversion) in most of the limb leads and chest leads following 5 d exposure to methomyl, a carbamate pesticide. Significant changes in plasma cholinesterase and lactic dehydrogenase activities were also noticed. The ECG changes could be reproduced in rabbits and were dose dependent. This type of ECG change following exposure to a carbamate compound is reported for the first time in occupationally-exposed subjects. The study results indicate that these changes are probably directly related to methomyl rather than its toxicity through cholinesterase inhibition. The significance of these changes remain to be investigated.

Clinical and biochemical investigations to evolve early diagnosis in workers involved in the manufacture of hexachlorocyclohexane

Summary365 individuals exposed to hexachlorocyclohexane (HCH) during its manufacture were studied and compared with 146 controls. These 502 cases were divided into five groups on the basis of serum total HCH levels. Exposure was mainly through skin. Results indicate that neurological symptoms reported were due to recent exposure to HCH and were related to the intensity of exposure. ECG abnormalities were seen in exposed cases. A significant positive correlation to liver related enzymes γ GT, LAP and Alp. P was observed. β -globulins significantly increased along with an increase in total HCH. Changes in IgM levels were similar as observed in IgA. Remarkably high concentration of HCH residues were found in the serum samples of all exposed workers. β-HCH contributed more than 80% of the total HCH built up. Presence of circulating immune complexes was also detected in representative samples. Further, repeated biological monitoring was advised to be carried out among such workers exposed to HCH, to evaluate signs of severe health impairment in them.

Clinical effects and cholinesterase activity changes in workers exposed to phorate (Thimet)

Phorate (Thimet), an aliphatic derivative of phosphorus is a highly toxic insecticide. In order to implement the safety measures, the clinical manifestations and cholinesterase (ChE) activity were evaluated before and after 2 weeks of exposure to this insecticide in 40 male formulators. The 2 weeks exposure reveal signs and symptoms of toxicity in 60% of the formulators. Gastrointestinal symptoms and lowering of heart rate (bradycardia) were more prominent as compared to the neurological symptoms. A significant depression in plasma ChE activity was observed at the end of 1st week (55%) and 2nd week (71%) as compared to the respective pre-exposure values. A recovery up to 79% of the pre-exposure activity of this enzyme was noticed 10 days after cessation of the above exposure.

Urinary excretion of benzidine in relation to the acetylator status of occupationally exposed subjects

1 Twenty-four male workers engaged in the manufacture of benzidine dihydrochloride for 1-4 years were included in this study. 2 Urinary levels of free benzidine were estimated by high-pressure liquid chromatography in all the workers. 3 Acetylator status of the workers was determined with sulphamethazine. 4 There was substantial absorption of benzidine over an 8-h work shift. 5 A significant correlation was observed between the rate of sulphamethazine acetylation and urinarv excretion of free benzidine.

Sequential changes in lactate, isocitrate, and malate dehydrogenases in mice exposed to technical grade hexachlorocyclohexane (BHC) and their possible relationship to liver tumors

Abstract Hexachlorocyclohexane (BHC) was fed at a 500-ppm-dose level in diet to pure inbred Swiss mice for 2, 4, 6, and 8 months. Later BHC was discontinued for 4 months and subsequently the animals were refed BHC for 1 month. The protein, lactate dehydrogenase (E.C.1.1.1.27), isocitrate dehydrogenase (E.C.1.1.1.42), and malate dehydrogenase (E.C.1.1.1.37) were studied from liver. The liver weight as percentage of body weight was also determined. The results showed an increase in the liver weight/body weight ratio and a decrease in protein and all three enzymes after BHC feeding for the different time intervals. The discontinuation of BHC in the diet resulted in the reversion of values of the above parameters toward the normal and after refeeding BHC for 1 month, the decreased values, as seen after initial BHC feeding, were again observed. This indicates that the changes in the values of lactate dehydrogenase, isocitrate dehydrogenase, and malate dehydrogenase are associated with hexachlorocyclohexane feeding in the diet. The significance of these changes is discussed.

Health risks in ultra-low-volume (ULV) aerial spray of malathion for mosquito control.

A field study was undertaken to evaluate health risks in persons engaged in ultra-low-volume (ULV) aerial application of technical malathion for mosquito control. No specific toxicity signs and symptoms were observed except nausea and irritation of eyes in a few cases. Observations on the ChE activity has revealed a significant depression in plasma at the end of spray operation in labourers employed in loading and unloading of insecticide and in field workers. Red blood cells ChE activity was not affected in any group of subjects. At the end of spray operation the insecticide residue on the grass used as cattle feed were about 315 ppm, which are much above the permissible level. However, 4 days after the application normal levels of the insecticide residues were detected.