P. B. Doctor

Toxicity of zinc in three microbial test systems

A feasibility study on the potential use of three bacterial test systems on the toxicity screening of zinc is presented. In this investigation, the toxicity screening procedures included, were the Microtox test using a luminescent halophyte bacterial strain, Photobacterium phosphoreum, a motility test employing Spirillum volutans, and a growth zone inhibition test using Bacillus cereus as the test organism. The EC50 value of zinc has been found to be 1.35 mg/L with the Microtox test under optimum test conditions (T15oct15min). However, the toxic response of zinc was significantly dependent upon the test temperature and incubation time. It decreased at higher temperatures and increased with longer incubation periods. In the case of the motility test, the minimum effective concentration (90%) value of zinc was 3.00 mg/L at optimum assay conditions (T28oct60min) while the toxicity of zinc in the growth zone inhibition procedure was found to be 2.25 mg/L at 30°C after 18 h incubation. Overall, the study showed that the Microtox test was the most sensitive screening procedure followed by the growth zone inhibition test, and the motility test was least sensitive among the three test systems. The growth zone inhibition procedure was the simplest of all the systems.

Intervention studies against green symptoms among indian tobacco harvesters

The use of rubber gloves reduced nicotine and cotinine absorption among 29 tobacco harvesters, as evidenced by the urinary excretion rate of nicotine and cotinine. Approximately 20% (n = 6) of the subjects reported that symptoms disappeared when they used gloves, but the remaining 23 workers complained of an occasional headache even when using gloves. Wearing of boots and socks as well as gloves prevented the symptoms and significantly decreased nicotine and cotinine excretion. This suggests that nicotine is absorbed through the feet.

Occupational Health Problems among Tobacco Processing Workers: A Preliminary Study

Occupational health problems among 100 tobacco processing workers were investigated. Symptoms, including vomiting, giddiness, headache, etc. were found among 69 exposed subjects. It was also observed that the excretion rate of nicotine and cotinine increased among exposed subjects. Biochemical parameters were found to be within the normal range. Electrocardiographic findings were non-specific and clinically there was no evidence of hypertension or ischemic heart disease. Therefore, the symptoms in tobacco processing workers might possibly result from mild nicotine toxicity.

Isolation and Identification of Gram Negative Bacteria from Raw Baled Cotton and Synthetic Textile Fibers with Special Reference to Environmental GNB and Endotoxin Concentrations of Textile Mill

The objective of this study was to examine the gram-negative bacterial (GNB) content of Indian raw baled cotton fibers and to compare with the U.S. cottons. Airborne endotoxin also was estimated in the different work places of the mill. On comparison with data on U.S. cottons, GNB content was found to be as high as in U.S. cottons. Moreover, endotoxin concentration of cardroom dust from an Indian cotton mill was found to be significantly (P less than 0.01) higher than in the research laboratory of the same cotton mill as well as in the cardroom of a synthetic mill.

A study of respiratory function among the workers engaged in ginning processes.

Background: Known respiratory health effects of exposure to cotton dust are mainly altered pulmonary function findings and symptom of chest tightness. A number of studies have been carried out all over the world to enumerate and evaluate the health effects of cotton dust exposed workers in different processes. However, such studies carried out in ginning industry especially in Indian context are scanty. Objectives: This study was initiated to explore occupational and morbidity details and respiratory functional status of the exposed workers as well as to investigate across the working shift pulmonary function changes. Materials and Methods: A cross-sectional study was conducted including workers from ginning units where principal exposure is from cotton dust. All the workers of the selected ginning units were subjected to an interview with a predesigned questionnaire to collect occupational and medical history, clinical examination and pulmonary function test. Results: In this present study, no cross-shift significant change in relation to PEFR and FEV1 values is observed. However, chronic effect on lung function is observed in a few subjects and declining trend of values was observed with increasing job duration as well as age of workers and among smokers. Other health problems among these subjects were backache and joint pain. Conclusions: Studies on cotton textile workers have shown both cross-shift and chronic decline of values. In this study on ginning workers, chronic effect only is observed. This difference of observation may be explained by different nature of exposure in case of ginning. This study recommends regular periodic clinical examination, lung function test and monitoring of dust, gram-negative bacteria and endotoxins in such workplaces.

A Preliminary Study on Gram-Negative Bacteria (GNB) and Their Endotoxins in a Gin House in India

The presence of byssinosis, an occupational disease found among cotton mill workers, has been well documented in different parts of the world. The disease develops due to exposure to environmental cotton dust. Evidence suggests that the causative agent for the disease is gram-negative bacteria (GNB) and their endotoxins present on the cotton fibers. An investigation was carried out in a gin house in western India. Environmental dust samples were collected by vertical elutriator (VE). Airborne dust concentrations were very high in the working environment: 2.11 mg/m3 in ginning and 0.95 mg/m3 in the press department (p < 0.05), which was higher than the threshold limit value collected by VE (0.2 mg/m3), and higher than the permissible exposure limit for respirable dust (0.5 mg/m3 for nontextile industries using cotton). In the office control site, the dust concentration was 0.31 mg/m3. The Occupational Safety and Health Administrations cotton dust standard permissible exposure limit for respirable dust is 0.2 mg/m3 in yarn manufacturing, 0.75 mg/m3 in slashing and weaving, and 0.5 mg/m3 in nontextile industries using cotton. These samples also showed high concentrations of airborne endotoxin (p < 0.001) in ginning and pressing (2.77 and 1.52 μg/m3) compared with the office control site (0.009 μ g/m3 measured by Limulus amoebocyte lysate technique). Total enumeration of airborne GNB was carried out qualitatively by the petri plate exposure method and quantitatively by an Andersen 6-stage viable sampler and VE. GNB were recovered in quite high numbers. Among all the GNB, Enterobacter agglomerans were the dominant bacterial flora. Results indicate that gin workers are occupationally exposed to airborne GNB and endotoxins, and require masks.

Toxicity screening of dye-contaminated river water using the Microtox system and its impact on microbial population

Abstract Textile dye-contaminated water samples were collected from five sites of river Bhadar: four from Jetpur (upstream) and one from downstream (Dhoraji). Toxicity endpoint was determined by Microtox™ using Photobacterium phosphoreum as the sensor organism. Site-specific dominant microflora (GNB) indicated that most of the isolates belonged to E. coli, and others were Enterobacter, Klebsiella and Pseudomonas etc. The study shows that bacteriological analysis of water samples can determine only its degree of microbial contamination but not its toxicity, as evident from the toxicity screening test carried out using Microtox™. The high toxicity corresponded to low bacterial numbers and vice versa.