The University of Calgary Environmental Science Program
ENSC 502 Project 
2003-2004
Impacts of Airborne Pollution from the 
Sour Gas Industry on Southern Alberta
 

J.W. Horne

This project involved 34 students from the fourth year Environmental Science Special Projects in Environmental Management course to study the impacts of the sour gas industry on southern Alberta in an 8 month program.  The students identified six areas for consideration 

INTRODUCTION

Sour gas, that is natural gas that contains more than 1% hydrogen sulphide (H2S), is associated with oil and gas activities and its processing. It has a powerful rotten egg odor that can be detected at very low concentrations in air (1 ppb = part per billion)  and can be fatal to healthy young adults when concentrations are 500 thousand times greater (250 to 500 ppm = parts per million).  Children, the elderly, and people who are ill may be susceptible at much lower concentrations than 250 ppm. Community standards set by the World Health Organisation (WHO) are set as low as 3 ppb (WHO: Environmental Health Criteria 19, hydrogen sulphide. Geneva: WHO International Programme on Chemical Safety, 48. 1982).  The difference in the level at which it can be detected and that which kills is huge and fuels public concerns regarding impacts due to sour gas emission on human and animal health and the impact on the environment. 

As natural gas is processed H2S is stripped from the natural gas stream and residual amounts are incinerated to form sulphur dioxide (SO2) which is released to the atmosphere.  Sulphur dioxide is less toxic than hydrogen sulphide but as it oxidizes it can form very fine suspended particles (aerosol sulphate) that penetrate deep into the lungs potentially causing respiratory distress. Therefore, except under rare circumstances (such as during flare events with wet gas (containing water) when H2S may not fully combust) sulphur dioxide and sulphate from sour gas processing are more likely to impact the enviornment and the health of people and animals in regions downwind than is hydrogen sulphide.

Sulphur dioxide and sulphate are compounds present naturally in the atmosphere and environment (from wood burning and from volcanoes for example) but based on measurements in ice cores global background concentrations are approximately 4 to 9 times higher due to fossil fuel combustion and industrial activities. In southern Alberta approximately 55 tons of S is released each day as residual sulphur dioxide from sour gas processing. The additional sulphur is dispersed over a wide region depending on the wind speed and terrain but if pulses of sulphur compounds are produced within a short time frame (days) or they impact the same area over longer periods of time (decades) acid rain and soil acidification can result. 

In this study subgroups of fourth year students from the Environmental Science Program at the University of Calgary were guided in studying the impacts of sulphur emissions from the sour gas industry on vegetation, soil, air and water in southern Alberta. Another group modeled sulphur deposition based on meteorological and  emissions data from sour gas plants in the area, and a final group examined the social and historical context of issues related to sour gas processing and flaring in the region.

The summary presentation can be accessed by clicking here.
Participants

Coordinator
Dr. A.L. Norman
Assistant Professor
Environmental Science
& Physics & Astronomy 

Social & Historical Context
Students:E. Baczuk, S. Burch, A. McCormick, L. Snowden, L. Willot, B. Smekal, M. Forrieter
Group Mentor: Dr. E. Dixon, Program Director (to 2004)
Envioronmental Science & Chemistry

Our group compiled an overview of the history and development of the region, an extensive review of literature pertaining to epidemiology and toxicology, an analysis of press handling of the subject in the Pincher Creek/Waterton area, a review of industry standards and regulatory compliance in the area, and collection and analysis of survey data regarding public risk perception and human health.

Air Quality Modeling
Students: T. Allen, M-E. Caron, S. Fargey, K. Lane, J. Romero
Group Mentors: Dr. P.Staniasek (AMEC Environmental) and M. Rawlings (Golder Associates) 
Our group described emission plumes from the gas plants so that potential exposure patterns could be better understood by modeling present day  emissions on both local and regional scales. Emissions of SO2 were modeled using the Industrial Source Complex Model Version 3 (ISC3) air dispersion model (EPA, 1995).

Air Quality Measurements
Students: A. Bowen, D. Couroux, C. Kwok, E. Sorensen
Group Mentor: Dr. A.L. Norman, Environmental Science Physics & Astronomy
Our portion of the study seeks to determine the spatial distribution and concentrations of sulphur dioxide and sulphate emissions. We will additionally be anaylzing the sulphur isotope concentrations in order to attempt to establish their original source.

Surface Water
Students: A. Barker, T. Chersa, A. Fraser, T. Harbidge, C. McKenzie, S. Morris
Group Mentor: Dr. C. Ryan, Environmental Science & Geology and Geophysics
Our group investigated potential contamination of surface and groundwater near the Shell Waterton sour gas plant, located near Pincher Creek, Alberta. It is postulated that sulphur compounds released here end up in local environmental receptors, such as ground and surface waters. This study researched the effects of sour gas processing on nearby surface and groundwater, by sampling the North Drywood Creek, other surface water bodies, and privately owned groundwater wells in the vicinity.

Soils
Our group examined the spatial variation in soil characteristics and SO42- concentrations downwind of one of the sour gas plants in the Pincher Creek area, including d34S which could be traced back to the source of emissions.  Parameters that were studied included pH, moisture, electrical conductivity (EC), buffering capacity (BC), cation exchange capacity (CEC), anion analysis (Cl- and NO3-), elemental sulphur, and isotope analysis (total sulphur, soluble sulphate, d34S).
Students: B. Albrecht, L. Hammer, M. Li, A. Nierlein, E. Rooney, S. Robertson, R. Yiu, N. Walters
Group Mentor: Dr. C. Ryan, Environmental Science & Geology and Geophysics

Vegetation
This group examined the chemical make-up of annual tree rings and needles of coniferous trees in south-western Alberta.  The purpose of this study was to document: (1) changes in the chemical composition of the environment before and after gas plant commencement and (2) the spatial relationship of  SO2 from sour gas emissions and coniferous trees. 
Students: H. Maguire, G. Pelchat, J. Rempel, J. Talerico
Group Mentor: Dr. M. Reid, Environmental Science & Biolgical Sciences
 

J. Talerico

 
BSc Environmental Science Program
University of Calgary



 
 
 

  • draws students and faculty from Biology, Chemistry, Physics, Geography, Geology, and Statistics 
  • integrated, scientific approach to environmental problems  
  • relies extensively on experiential  and field work 

This project was conducted within a 4th year Environmental Science course: Special Problems in Environmental Management (ENSC502)

Acknowledgements:

We would like to thank the following individuals for their input and participation in the study:
P. Staniasek (AMEC), Martin Rawlings (Golder), J. Baxter (U. of Western Ontario), Residents of Pincher Creek, M. Judd (resident), S. McRae (resident), A. Hepner (resident), J. Russel (resident), A. Nixon (Shell).