Work environment of automated and non-automated rice mills in Amapara district, Sri Lanka

K. R. M. Chandrathilaka, S. R. De Alwis Seneviratne, K. N. Lankatilake, D. B. D. L. Samaranayake, A. K. Karunarathna


Background: Paddy cultivation is a major occupation in informal sector in Sri Lanka. In 2014, contribution of the agricultural activities to the country’s annual GDP was 9.9% of which, contribution by paddy was 11.3%. The objective of the current study was to describe the work environment in rice mills with respect to dust, humidity and thermal condition, ventilation and illumination.

Methods: A cross sectional study in 107 randomly selected rice mills was carried out in Ampara district in Sri Lanka. Standardized measurements were carried out to assess internal work environment of the mills.

Results: Milling activities showed a seasonal variation. The majority of the mills (95.3%) manufactured raw rice only. Other than the basic characteristics, both automated (AMs) and non-automated mills (NAMs) showed common features. All rice mills exceeded the threshold limit values for total (520.04 mg/m3, SD=191.86 mg/m3) and respirable dust (48.14 mg/m3, SD=9.4 mg/m3). Mean daytime indoor relative humidity in the majority of the mills (n=102, 95.3%) was within the accepted upper limit. In most of the mills, ventilation (n=84, 78.5%) and illumination in polishing/packing area (n=60, 56.1%) was satisfactory while in dehusking/paddy inlet area (n=96, 89.7%), illumination was below the limits.

Conclusions: Work environment in both the AMs and NAMs in Ampara district presented with poor work standards compared to the required guidelines.



Dust exposure, Occupational health, Rice milling, Thermal comfort, Work environment

Full Text:



Department of Census and Statistics, Sri Lanka. Paddy Statistics: Extent, Sown, Harvested, Average Yield and Production by District: 2014 Yala Season. 2014; Available at: agriculture/Paddy%20Statistics/PaddyStatsPages/2014yala(MT).pdf. Accessed 20 May 2015.

Department of Census and Statistics, Sri Lanka. Paddy Statistics: Extent, Sown, Harvested, Average Yield and Production by District: 2013/14 Maha Season. 2014; Available at: http://www.statistics. Accessed on 20 May 2015.

Abeysekara NTQM. A study of the respiratory and other disorders in rice millers following exposure to dusts of occupational origin. University of Colombo; 1994.

Batsungneon K, Kulworawanichpong T. Effect of Dust Particles in Local Rice Mills on Human Respiratory System. World Acad Sci Eng Technol. 2011;56:260-5.

International Rice Research Institute. Milling, Rice Knowledge Bank. No date; Available at: Accessed 21 June 2015.

Palipane KB. Milling and Quality Improvement in Rice. Institute of Post-Harvest Technology, Anuradhapura. No date; Available at: Accessed 11 November 2016.

International Rice Research Institute. Milling Systems, Rice Knowledge Bank. No date; Available at: Accessed 21 June 2015.

Lim HH, Domala Z, Joginder S, Lee SH, Lim CS, Abu Bakar CM, et al. Rice millers' syndrome: a preliminary report. Br J Ind Med. 2012;41(4):445–9.

International Labour Office. Recording and notification of occupational accidents and diseases; An ILO code of practice. 1996; Available at:

Simpson JCG, Niven RM, Pickering CAC et al. Prevalence and predictors of work related respiratory symptoms in workers exposed to organic dusts. Occup Environ Med. 1998;55(10):668–672.

Desai MR, Ghosh SK. Occupational exposure to airborne fungi among rice mill workers with special reference to aflatoxin producing A. flavus strains. Ann Agric Environ Med. 2003;10(2):159-62.

Fishwick D, Barber CM, Bradshaw LM, et al. Standards of care for occupational asthma. Thorax. 2008;63(3):240–50.

Department of Labour. Factories (general standards of lighting) Regulations, Sri Lanka. 1965.

World Health Organizaton. Hazard Prevention and Control in the Work Environment: Airborne Dust. 1999; Available at: occupational_health/publications/en/oehairbornedust3.pdf.

NIOSH. Particulates not Otherwise Regulated, Respiarble: Method 0600. NIOSH Manual of Analytical Methods (NMAM). 4th ed. 1998. 3.

NIOSH. Particulates not Otherwise Regulated, Total: Method 0500. NIOSH Manual of Analytical Methods (NMAM). 4th ed. 1994. 2.

Health and Safety Executive. Management of risk when planning work: The right priorities. 2015. Available at: lwit/assets/downloads/hierarchy-risk-controls.pdf. Accessed 20 March 2015.

Department of Meteorology, Sri Lanka. Summary Data-Relative Daytime Humidity and Daytime Temperature. 2014.

Arundel V, Sterling EM, Biggin JH. Indirect Health Effects of Relative Humidity in Indoor Environments. Environ Health Perspect. 1986;65:351-61.

Baughman A, Arens EA. Indoor Humidity and Human Health Part I: Literature Review of Health Effects of Humidity-Influenced Indoor Pollutants. ASHRAE Transactions. 1996;102(1):193-211.

Ismail AR, Rani MRA, Makhbul ZKM. A Study of Relationship between WBGT and Relative Humidity to Worker Performance. World Acad Sci Eng Technol. 2009;3(3):257-62.

US Department of Labour. Heat Stress. Occupational Health and Safety Administration. 1999. Available at: osta/otm/otm_iii/otm_iii_4.html Accessed on 12 December 2012.

Urban Development Authority. City of Colombo Development Plan - Volume II. 2001. Available at: Accessed 18 January 2015.

Department of Labour. Occupational Safety & Health and Payment of Workmen’s Compensation. In: Factories Ordinance. 1950; Available at: Accessed on 12 December 2012.

Vimalanathan K, Babu TR. The effect of indoor office environment on the work performance, health and well-being of office workers. J Environ Health Sci Eng. 2014;12:113.

World Health Organization. Occupational health; A manual for primary health care workers. 2001. Available at: health/regions/en/oehemhealthcareworkers.pdf. Accessed 10 September 2015.