Environmental and Occupational Health
During the year under report, studies in the area of environmental and occupational health were carried out by the Council’s National Institute of Occupational Health (NIOH), Ahmedabad and its Regional Centres at Bangalore and Calcutta in workers engaged in various industries such as chemicals, automobile, mining etc. and grain and tobacco handlers as well as on air and water pollution.
Assessment of the Health Status of Subjects exposed to Chemicals/Gases evolved due to Accidental Fire in a Godown
An accidental fire broke out in April 1998 in a godown located in one of the industrial estates of Calcutta, used by custom clearing agents for keeping the items pending clearance of custom duties. A huge quantity of chemicals (mainly organic) was stored in the godown. One hundred and thirteen subjects were admitted to hospital, out of which seven died. A study was undertaken to assess the health status of exposed subjects and follow them up to ascertain the effect of the exposure, if any.
A total of 453 exposed subjects (Community 220; Fire Brigade 203; Police 30) were clinically examined. The predominant symptoms were headache (33.48%), vertigo (30.17%), nausea (22.68%), irritation of mucus membrane (28.63%), eye irritation (18.32%), skin irritation, itching and burning (6.60% to 16.74%), tingling (11.26%), joint pain (13.21%), panic attack (5.96%) and anaemia (17.89%). Higher values of SGOT (>40 IU/l) were also found in 50.88% and SGPT (>40 IU/l) in 46.25% of the workers. The pulmonary function test indicated presence of mainly restrictive impairment (Fire Brigade - 11.8%, Police - 13.8%, Community - 10.2%) with obstructive impairment being comparatively less (3.2%). Thus, it seems that nervous system, liver and respiratory systems are mostly affected.
Considering the nature of exposure (chemicals) it was decided to include reproductive outcome as well as genotoxicity in the study. Suitable control subjects for each category will also be examined.
Biological Markers of Manganese Exposure and Effect in Manganese Exposure and Effect in Manganese Miners
Recent revelations of lead toxicity even at very low levels has led to the search for suitable alternate additive to increase the octane number of petrol. One such compound, methylcyclo-pentadienyl manganese tricarbonyl (MMT), has been in use in Canada and some other parts of the world. The toxic effects of manganese at high exposure levels are well known but there are conflicting reports on manganese toxicity at low levels of exposure. To study the effects of manganese at low levels of exposure an environmental and medical study has been initiated by NIOH in Collaboration with US Environmental Protection Agency.
It is planned to measure the environmental exposure in underground manganese mines and study the health effects of manganese at different levels of exposure using magnetic resonance imaging (MRI) and neurobehavioral tests.
During the first phase of the programme, ambient air sampling for manganese was carried out at different work places and in the vicinity of manganese mines at Balaghat, M.P. The samples were collected with stationary samplers and personal samplers for 3-8 h during underground mining and surface mining, and at one ferro manganese plant and its vicinity.
The results show that during surface mining, the respirable dust concentrations ranged from 175.05-295.81 µg/m3 at vertical holm shaft and from 99-456 µg/m3 at the crusher and manual breaking and dressing units. At drilling points during underground mining the values ranged from 172.8-614.8 µg/m3 and at the furnace units in the ferro manganese plant it ranged from 763.1-1282.0 µg/m3. The manganese content in the respirable dust ranged from 1.56-39.16 µg/m3 during surface mining, from 2.2-83.33 µg/m3 during underground mining, and from 33.22-75.73 µg/m3 at the ferro manganese plant. In the vicinity (administration building, guest house, and hospital), the respirable dust concentrations were in the range of 4.92-15.7 µg/m3 with manganese content ranging from 1.3-2.0 µg/m3.
A total of 476 underground manganese miners with duration of exposure from 5 to 35 yr were evaluated by standard medical questionnaire, computerized spirometry, chest radiography, estimation of manganese in blood and urine and assessment of liver function and thyroid functions. In the second phase of the study, MRI and behavioral tests will be done on subjects selected on the basis of blood manganese levels and clinical parameters.
Effect of Lead in Children and Adolescent Development and Puberty
A long term follow up study was undertaken in school children at Ahmedabad and Calcutta to examine the effects of lead on adolescent development and puberty. The results of the first phase of the study at Ahmedabad showed higher mean age, though statistically non-significant, for various indicators of sexual maturity rating (SMR) in children having blood lead levels higher than 10 mg/dl.
During the current year, the study was extended in 705 children (384 boys and 321 girls) of a school situated near a lead smelter at Calcutta. Analysis of blood lead levels showed that 69.4% of the students had levels <10µg/dl, 25.2% between 10.0 and 14.9 µg/dl, 4.7% between 15.0 and 19.9 µg/dl and 0.7% > 20.0 µg/dl respectively.
SMR for pubic hair in stages-1-3 did not show any significant difference in the mean age of onset in boys with low lead levels (<10µg/dl) and high levels (>10µg/dl). The SMR of external genitalia for boys also showed no difference in the mean age for stages 1-4 in both the high and low lead level groups.
The mean age of onset of menstruation was 13.91 yr and 13.58 yr for low and high blood lead level groups respectively. The SMR of pubic hair for girls with high blood lead levels in stages 2 and 3 was delayed as compared to that in girls with low blood lead levels. The study is continuing.
Air Pollution due to Vehicular Traffic in Major Cities/Towns of Gujarat State
Air pollution caused by motorized vehicles was assessed to examine the air quality in eight cities of Gujarat viz., Ahmedabad, Vadodara, Surat, Rajkot, Bhavnagar, Jamnagar, Vapi and Mithapur. High volume samplers were used to monitor ambient air at four typical traffic junctions in each city during peak hours. Analysis of the samples was made for respirable particulate matter (RPM), NO2 and CO. The results show that the air quality was found to be very poor in Ahmedabad, Vadodara, Surat and Bhavnagar. The values for RPM, NO2 and CO were: 163-866 µg/m3, 11-105 µg/m3 and 8-33 ppm respectively in Ahmedabad; 99-3193 µg/m3, 20-113 µg/m3 and 5-35 ppm in Vadodara; 224-1045 µg/m3, 20-156 µg/m3 and 1-9 ppm in Surat; 126-1495 µg/m3, 6-258 µg/m3 and 0-9 ppm in Bhavnagar as compared to the air quality standards of 100 µg/m3, 80 µg/m3 and 1.75 ppm respectively (National Air Quality Standards). The values for RPM, CO, and NO2 in the four cities were within the recommended air quality standards.
Air Pollution with respect to Levels of Polynuclear Aromatic Hydrocarbons in High Traffic Density Areas of Bangalore City
The objective of the study was to assess the quality of air in high traffic density areas of Bangalore city with reference to adverse health consequences among the general population. Eight hours continuous air monitoring for total suspended particulate matter (SPM) using high volume sampler was carried out in two high traffic density areas covering eight locations and one residential area (control area) covering three locations. Levels of total SPM were very high ranging 258.93-956.44µg/m3 in high traffic density area compared to 62.24-205.93µg/m3 in the residential area. The samples will be analyzed for polynuclear aromatic hydrocarbons with HPLC. The study conducted during summer season will be followed up in the winter season as well.
Development of Toxicity Testing Methods for Industrial Effluents
This multi-institutional project is an ongoing project sponsored by Central Pollution Control Board (CPCB), New Delhi. The aim of the project is to develop an aquatic toxicity parameter for the industrial effluents for regulatory purposes. During the year under report, untreated and treated industrial effluents were collected from six dye and dye-intermediate industries situated at Roha and Mumbai (Maharashtra).
The physico-chemical parameters for the diluent water used in the study were - pH:7.8–8.0, water temperature: 25 ± 1°C, total hardness: 220–240mg/l, alkalinity: 44–60mg/l and conductivity: 0.5–0.7 mS.
The final experiments were conducted using fresh water fish Brachydanio rerio in duplicate with the control sets. The fish were exposed to a minimum of five dilutions of the effluents for 48 h. and mortality of the fish was recorded at intervals of two hours for 24 h. The experiments were performed along with the reference toxicant potassium dichromate.
The results show that the value of 48 h. toxicity factor (TF) for the reference toxicant was 100 mg/l and that of the untreated effluents was in the range of 4-250mg/l, intermediate effluents 2-64mg/l and treated effluents 1-8mg/l.
Reclamation of Vrishabavathi River Water - A Sociological Study
In continuation of our earlier study, the present investigation was aimed to assess the knowledge gained by community regarding water pollution and recycling of contaminated river water. A total of 1800 subjects were covered in the questionnaire survey. Analysis of 200 questionnaires indicates that nearly 82.5% of the population did have the knowledge regarding the existing river water pollution. It was reported that 66.6% of the population knew about recycling of contaminated river water. Acceptance of the recycled river water was reported by 48.5% of the population. Nearly 91% of the population did not use this water for any purpose, while 7.5 % of the population used it for agriculture. The study is being continued.
Occupational Health Hazards among Automobile Transport Workers
In seven public automobile transport garages in Calcutta city, a large workforce of 300-2000 workers is employed. However, very little is known about the health status of this group of workers. Therefore, a study was undertaken to assess the work environment, personal exposure to NO2, CO, RPM, VOC (volatile organic compound) etc. as well as health surveillance covering work stress and postural discomfort from ergonomic point of view.
Environmental monitoring following standard methods was done using high volume sampler, cascade impactor and personal sampler. The dust concentrations in different areas of the garage varied between 0.131 and 0.307 mg/m3 for total dust; and 0.039 and 0.133 mg/m3 for respirable dust. Benzene soluble matter (BSM) in different areas ranged between 0.020 and 0.036mg/m3. Concentration of trace metals like Fe, Cr, Pb, Cu, Cd was within the prescribed limits. Pulmonary function tests (PFTs) of 181 subjects revealed restrictive (34.3%), obstructive (11.6%) and combined (7.2%) types of impairments. On medical examination of 185 males common symptoms were pain in abdomen (33.5%), cough (30.2%), sputum (34.05%), breathlessness (42.8%), ringing in ears (20.0%), partial hearing loss (10.2%) and itchiness of skin. Chronic bronchitis (23.2%), anaemia (29.2%), and rhonchii (7.0%) were detected on examination. High blood pressure (>140/90 mm of Hg) was noted in 3.2% of the workers (drivers 3.17%; conductors 6.5%). Systolic blood pressure >140 mm of Hg was seen in 10.8% of subjects examined (drivers 7.9%; conductors 19.6%; mechanics 11.3%). Diastolic blood pressure >90 mm of Hg was found in 4.3% of the subjects (drivers 4.6%; conductors 6.96%). The workloads of drivers, conductors and mechanics were ‘moderate’ to ‘difficult’ and that of administrative staff ‘easy’ to ‘moderate’. Pain and discomfort felt in different parts of the body were also reported (drivers 67%; conductors 60%). The study is being continued in different garages.
Prevention, Control and Treatment of Silicosis and Silico-tuberculosis in Agate Industry
A new design of agate grinding machine has been developed. An impeller of 12 blades has been incorporated instead of 8 blades made in the earlier design, with the electric consumption remaining more or less the same. The installation of this machine at Khambhat in Gujarat showed that the suction capacity of the exhaust increased to 325 cubic feet/min (cfm) from 200 cfm, with reduction of the respirable dust by 90% and total dust by 95% in the ambient air.
Occupational Health Problems of Tobacco Harvesters and their Prevention
Occupational health problems associated with tobacco cultivation are known as Green Tobacco Sickness (GTS). It is a mild and acute form of nicotine toxicity that affects tobacco workers who have direct dermal contact with tobacco plants during cultivation and harvesting. To detect the chronic health effects of tobacco cultivation, a specially designed questionnaire was used which included tobacco habits, occupational and reproductive history, detailed medical examination, examination of cardiovascular system and the eyes. Another important objective of the study was to find out which types of gloves are acceptable and effective in preventing the dermal absorption of nicotine with reference to the work related symptoms and urinary excretion rate of nicotine and cotinine amongst tobacco harvesters. Further trials are being made with different types of hand gloves such as cotton, rubber, disposable polyethylene, cotton with polyester, nylon (polyamine), polyester, cotton coated on palmer side with PVC polka dots and cotton coated with natural rubber on palmer side.
A total of 685 exposed subjects (457 men and 228 women) were examined. Hypertension was observed in 17.7% of the men and 18.0% of the women. Abnormalities of visual acuity were noted in 26.5% of the men and 26.0% of the women. The work related symptoms such as nausea, vomiting, giddiness, loss of appetite, fatigue, etc. were reported by 42.7% of the men and 55.7% of the women. Initial feedback from the workers suggested that cotton gloves were more acceptable and comfortable in wear. Further work is in progress.
Occupational Health Problems among Workers dealing with Newspaper Refuse
During the reporting period, air-borne fungal flora obtained from three newspaper refuse sites using Andersen-6-stage viable sampler were processed for identification. The total number of isolates from sites I, II and III were 1.30 x 103, 1.25 x 103 and 1.41 x 103 respectively.. The number of isolates belonging to genus Aspergillus were 19.80, 16.30 and 27.30% respectively. Different species of Aspergillus identified morphologically from among these isolates were 4.4, 27 and 25% for Aspergillus flavus, 0.5, 10.6% and nil from A. parasiticus; and 2.6, 3.6 and 1.2% for A. glaucus. Other species included A. niger, A. nidulans, A. fumigtus, A. versicolor etc. Special attention was given on the identification of A. flavus and A. parasiticus since these species are responsible for production of aflatoxin. Identification of toxigenic strains of A. flavus and A. parasiticus is under progress using qualitative media like Czapex with anisaldehyde, aflatoxin producing ability (APA) agar medium, coconut agar media (CAM) etc. Airborne spores of other fungal species like Cladosporium, Alterneria, Fusarium etc. were also recovered from these sites. Inhalation of these spores is known to produce bronchial asthma. The study is ongoing.
Assessment of Occupational Health Hazards among Storage Grain Handlers
Foodgrains are stored by different agencies like Food Corporation of India, Central Warehousing Corporation etc. The workers are engaged in transporting foodgrains from one place to another inside these godowns for storage and delivery, resulting in exposure to various types of environmental contaminants. These foodgrain handlers are exposed to respiratory hazards from bacteria and fungal spores growing on foodgrains and the proteins of rodents, pesticides, etc. Physical labour results in rapid and deep breathing which makes the workers more susceptible to respiratory hazards. No comprehensive data is available on the health status of these workers.
A study was undertaken to evaluate the health status of the grain handlers along with measurement of fungal spores in the work environment. Measurement of grain dust levels and evaluation of efficiency of the workers was also done.
A total of 140 workers (handling labour 46; quality control 39; ancillary 32; administrative 23) were covered for the present phase of the study. Medical history was recorded using standard proforma with special emphasis on occupational history and history related to allergic symptoms relating to conjunctiva, nose, skin etc. The symptoms recorded were redness of eyes (5.79%), eye itching (28.69%) and watering from eyes (10.87%). Running nose, urticaria and pruritis were noted in a relatively small number of subjects. Cough (22.46%), sputum (19.56%), shortness of breath (35.58%), joint pain (30.43%) and low back pain (33.33%) and itching of the skin (5.07%) were the other important complaints. High blood pressure (>140/90 mm of Hg) was seen in 24.63% of the workers. Rhonchii (10.14%) and crepitations (2.89%) were observed in the lungs and the PFTs showed restrictive type of disorder in 7.8%, obstructive disorder in 7.1% and mixed in 1.42% of the workers. The ancillary workers were found to be most affected. Post-shift PFTs showed decrement in 53.8% subjects. Positive broncho dilation test was noted in 4 of 5 subjects tested. Concentration of fungal spores (Aspergillus, Cladosporium, Alternaria etc.) was very high inside the godown. Some subjects (23.5%) reported pain and discomfort in different parts of the body. The project is ongoing.
Analysis of Industrial Accidents and Structurization of Database
A total of 593 fatal injury cases occurring in Gujarat during 1995-97 were recorded and analysed. About 64% of the deaths occurred in the chemical, textile, shi p breaking and engineering industries and 60% of the victims were under the age of 30 years. Slips and fall injuries (e.g., fall on ground, fall from height) resulting in death of about 25% of the total cases were recorded during the study period. Machine related accidents (e.g., struck by machine, caught in machine) represent about 19% of the cases. Data suggest that many of the industrial injuries are preventable provided the industrial units follow appropriate method of accident investigation and analysis. For example, about 45% of the victims could have been saved if they were equipped with head gear and harness belt. Detailed analysis of the data is being carried out.
Toxicity and Exposure Assessment through Microbial Screening
The usual practice of evaluation of toxicity screening in case of ‘Growth Zone Inhibition test’ using sensor organism Bacillus cereus is to express either qualitatively or semi-quantitatively results depending upon the production of ‘halo’. Considering this, a study has been carried out to establish a quantitative technique as an alternative to ‘Growth Zone Inhibition test’ using the same sensor organism (B. cereus). The study was initiated with mercury (Hg2+). The toxicity of Hg2+ as worked out in ‘Growth Zone Inhibition test’ was 0.1 ppm. Determination of MIC (minimum inhibitory concentration) and MAC of Hg2+ using B. cereus as the test organism is under progress.
Identification of Carcinogen-Haemoglobin Adduct in Benzidine exposed Workers
Benzidine is a potent carcinogen. The earlier findings on workers exposed to benzidine and benzidine-based dyes revealed that exposure status and excretion pattern of benzidine metabolites strongly correlated with the level of DNA-benzidine adducts in exfoliated urothelial cells. To examine the haemoglobin-adduct level, the blood samples were collected from 33 exposed (15 exposed to benzidine and 18 to benzidine-based dye e.g. Direct Black 38) and 15 control subjects matched for age, sex and socio-economic status. The analysis of samples for acetylated benzidine-Hb adduct level is being done in collaboration with the National Cancer Institute (NCI), USA.
The findings revealed that the Hb adducts of acetylated benzidine were non-detectable in the control subjects. However, it was present at relatively low level in benzidine dye exposed workers and at a very high level among benzidine exposed workers. Comparatively, the Hb adduct content was 18 times higher in benzidine exposed workers than the benzidine dye exposed workers.
NIOH Poison Information Centre - Organophosphate (OP) Pesticide Poisoning
Of the 377 cases of poisoning registered at the Centre, 113 (30%) were found to be of OP- poisoning. The cases of OP- poisoning were highest in the age group of 21-30 yr (46.9%) with 85% males and 15% females. Most frequent cause of poisoning was found to be suicidal (73.5%), the other causes being occupational (15%), accidental (8%), and unknown (3.5%). The exposure through oral route was found to be the most frequent (78.8%) followed by inhalation (15.9%) and combined i.e. inhalation and dermal (5.3 %). The OP-poisoning cases (44.2%) were found to be the most severe (severity score-3) requiring 8-38 days of hospitalisation. During the year, the frequency of OP poisoning was found to be higher in August and February. The farmers/farm labourers represented the highest number (42.5%). Sixty nine per cent of cases were either uneducated or had a primary level education. The above data indicate that OP insecticides continue to cause high morbidity. The commonest agents encountered were chlorpyriphos, dimethoate, phrate and monocrotophos.