Work-exposure to PM₁₀ and aromatic volatile organic compounds, excretion of urinary biomarkers and effect on the pulmonary function and heme-metabolism: A study of petrol pump workers and traffic police personnel in Kolkata City, India

ABSTRACT

This study focused work-exposure to particulate matter ≤ 10 µm (PM₁₀), volatile organic compounds (VOCs) and biological monitoring of major VOCs (BTEX) to observe the significant effects of traffic related pollutants on respiratory and hematological systems of workers engaged in two occupational settings, petrol pumps and traffic areas of Kolkata metropolitan city, India. PM₁₀ was assessed by personal sampling and particle size distribution by 8-stage Cascade Impactor. VOCs were analysed by gas chromatography-flame ionization detector (GC-FID) and five urinary metabolites, trans trans- mercapturic acid (tt-MA), S-phenyl mercapturic acid (SPMA), hippuric acid (HA), mandelic acid (MA) and methyl hippuric acid (MHA) of VOCs, benzene, toluene, ethyl benzene and xylenes (BTEX) by reverse phase high performance liquid chromatography (HPLC). Pulmonary functions test (PFT) was measured Spirometrically. ∂-aminoleavulinic acid (ALA) and porphobilinogen (PBG) in lymphocytes were measured spectrophometrically following column chromatographic separation. High exposure to PM₁₀, having 50% of particles, ≤ 5.0 µm in both the occupational settings. Exposure to toluene was highest in petrol pumps whereas benzene was highest (104.6 ± 99.0 μg m⁻³) for traffic police personnel. Workplace Benzene is found many fold higher than the National ambient standard. Air-benzene is correlated significantly with pre- and post-shift tt-MA (p < 0.001) and SPMA (p < 0.001) of exposed workers. Blood cell counts indicated benzene induced hematotoxicity. ALA and PBG accumulation in lymphocytes indicated alteration in heme-metabolism, especially among traffic police. Significant reduction of force exploratory volume in one second (FEV₁) and forced vital capacity (FVC) of fuel fillers are observed with increased tt-MA and SPMA. Study revealed PFT impairments 11.11% (6.66% restrictive and 2.22% obstructive and combined restrictive and obstructive type, each) among petrol pumps and 8.3% obstructive type among traffic police.

KEYWORDS:

• ∂-Aminolaevulinic acid
• benzene
• FEV₁
• personal exposure
• PM₁₀
• urinary metabolites
• tt-MA
• SPMA
• solid phase extraction
• porphobilinogen
• pulmonary function test
• VOCs

Acknowledgment

The authors are thankful to the Director, National Institute of Occupational Health, Ahmedabad and Officer-in-Charge, Regional Occupational Health Centre (Eastern), Kolkata, for providing all necessary infra-structural support for conducting the project work.

The authors wish to express their sincere thanks to the authorities of different fuel distribution agencies, the petrol pump authorities and also to the employees of petrol pumps who have volunteered themselves as study subjects. The authors also extend sincere thanks to the Commissioner of Police, Kolkata and the Traffic Commissioner, Kolkata for extending their whole hearted support in the study. The authors are thankful to Sri Sukanto Pal, Field Assistant (Project), Jane Alam, Technician C of this Centre, for assisting in carrying out field study of the project.

Funding

The authors wish to express their sincere thanks to the Department of Health Research, Indian Council of Medical Research, New Delhi, for funding the project.