View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by eScholarship - University of California UC Irvine UC Irvine Previously Published Works Title Peat Fires and Air Quality: Volatile Organic Compound and Particulates Permalink https://escholarship.org/uc/item/2wn9j3vn Journal Chemosphere, 76(3) Authors Blake, DR Hinwood, AL Horowitz, P Publication Date 2009 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Chemosphere 76 (2009) 419–423 Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere Short Communication Peat fires and air quality: Volatile organic compounds and particulates D. Blake, A.L. Hinwood *, P. Horwitz Centre for Ecosystem Management, Edith Cowan University, 270 Joondalup Drive, Joondalup 6027, Western Australia, Australia article info abstract Article history: There are numerous localized peat deposits on the Swan Coastal Plain, an urban and rural bioregion Received 7 October 2008 otherwise dominated by wetland ecosystems in southwestern Australia. Hydrological change is signifi- Received in revised form 13 March 2009 cant in the bioregion: urban development encroaches on wetlands, groundwater extraction provides Accepted 16 March 2009 the city population with most of its water, and rainfall declines will not recharge aquifers in the future. Available online 25 April 2009 The wetland processes which contribute to the formation of these peat deposits have therefore changed and are becoming vulnerable to fire events with residents increasingly exposed to peat smoke. There is an Keywords: imperative to characterise this peat smoke to determine if exposures are harmful or toxic, and opportu- Peat nities to do so in this setting arise due to the absence of bushfire smoke which has confounded other Smoke Volatile organic compounds international studies. We have measured volatile organic compounds (VOCs) and particulate concentra- Wetland ecosystem change tions from an opportunistic assessment of two peat fires. SUMMA canister grab samples and a portable Human exposure GCMS were used to determine the VOCs with high 1 h benzene concentrations of 16 and 30 ppm v/v. Air pollution PM10 and PM2.5 particulate data were collected using an Osiris continuous analyser with 24 h concen- trations recorded at varying time periods (within a 5 months timeframe) ranging from 1 h maximums of between 23–37 lgmÀ3 for PM10 and 50.5–106 lgmÀ3 for PM2.5. While the 24 h averages were gener- ally below national air quality standards, elevated 1 h concentrations were observed on numerous occa- sions and on most days. Given the proximity of residential development to many peat deposits, a drying climate and the increased risk of arson in peri-urban environments, the health impacts of exposure to peat smoke need to be determined and if necessary measures developed to prevent exposure (which would include maintaining wetland sediment integrity so as to reduce its vulnerability to fire). Crown Copyright Ó 2009 Published by Elsevier Ltd. All rights reserved. 1. Introduction for drinking and irrigation supplies, groundwater levels continue to decline (Appleyard et al., 1999, 2004), resulting in a vulnerabil- Peat deposits associated with inland freshwater ecosystems of ity of organic rich sediments to fire events as the amount of sedi- the Swan Coastal Plain (SCP), a bioregion dominated by wetland ments exposed to drying, and the duration for which they ecosystems in southwestern Australia, are becoming increasingly remain dry, both increase. Incendiary events associated with vulnerable to fire events. Changes in climate, hydroperiod and peri-urban fronts have increased the number of fire events occur- urbanisation and the incendiary habits of humans are all factors ring in the region, with a consequent increase in the frequency of which have led to an increased vulnerability and incidence of fire wetland fires. in these wetland systems (Horwitz et al., 1998; Horwitz and Som- By their very nature peat fires are difficult to extinguish and mer, 2005; Semeniuk and Semeniuk, 2005; Smith and Horwitz, tend to burn for extended periods, generally from the summer fire 2005). Apart from the obvious threat to wetland function, wetland period until extinguished by winter rains. Persistent fires burning biodiversity and water quality, there are also considerations for in peat sediments bring complaints from nearby residents, high- human health associated with the resultant smoke from peat fires: lighting the imperative to investigate the characteristics of smoke people are living adjacent to wetlands in urban and peri-urban emanating from these fires particularly in the Australian context settings. where urban development is expanding, increasing the risk of fire Over the last two decades changes in rainfall patterns for the and also the opportunity for exposure to resultant smoke. bioregion have shown a significant decline, reducing the recharge Smoke from peat fires can be intense and episodic and is of the superficial aquifer which supports numerous wetland eco- strongly linked to the rate of combustion. Combustion and the sub- systems (Appleyard et al., 2004). Coupled with a history of rela- sequent products are therefore influenced by sediment type, mois- tively unregulated and unconstrained abstraction of groundwater ture content of the soil and climatic conditions such as temperature and humidity and incomplete combustion processes * Corresponding author. Tel.: +61 8 6304 5372; fax: +61 8 6304 5509. (DeBano et al., 1998; Grishin et al., 2006). In addition the smoke E-mail address: [email protected] (A.L. Hinwood). from burning peat can be intermixed with smoke from burning 0045-6535/$ - see front matter Crown Copyright Ó 2009 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2009.03.047 420 D. Blake et al. / Chemosphere 76 (2009) 419–423 fallen vegetation. The resultant smoke can have an impact on near- rubbish was set alight on top of dry sediments, and continued in by residents over a long period of time as well as presenting a risk a southerly direction. A limestone trench was installed approxi- to those charged with managing the fire scene. mately 2.5 km from the northern end of the lake in an attempt to Peat smoke is made up of a complex mixture of gases and fine prevent the fire spreading further south. In February 2006, with particles (Itkonen and Jantunen, 1983; NCDENR, 1998). Studies of the northern part of the lake still burning, fire from neighbouring the composition of peat smoke report that in addition to carbon bushland entered the lake, south of the trench. This resulted in (the element that dominates the atmospheric release), sulphur, two smouldering fronts moving towards each other, and the loss potassium, oxides of nitrogen, particulates, polycyclic aromatic of extensive amounts of organic matter. hydrocarbons and volatile organic compounds (VOCs) are also pro- duced (Ramadan et al., 2000; Gebhar et al., 2001). Both PM2.5 and 2.2. Sampling for VOCs PM10 have been associated with peat smoke with PM2.5 being considered the predominant fraction (Joseph et al., 2003). Two 1 h SUMMA canister samples were taken at Lake Wilgarup, Silica may also be involved where diatomaceous sediments are one sample close to the peat smoke (within sediment smoke plume burnt (Semeniuk and Semeniuk, 2005). These chemicals in isola- at groundlevel) and another 1–2 m downwind of the smoke, tion have been shown to have a range of health effects in a range approximately 1.5 m above ground level. A Hapsite portable GC– of occupational settings (IPCS, 1993; WHO, 1999; Merget et al., MS (gas chromatograph–mass spectrometer) (INFICON) was also 2002; Newhook et al., 2003). deployed and sampled smoke at the site of release to air in order Although plausible that there might be health effects associated to characterise the composition. Due to health and safety concerns with exposure to smoke from burning peat, few epidemiological and safety concerns relating to unstable nature of burnt/burning studies have focused specifically on the health impacts of peat sediments, access and instrument deployment times were re- smoke. A few studies of the impacts of smoke arising from fires stricted thus preventing the acquisition of accurate instrument which originated from peat have been conducted (Emmanuel, location and extended sampling times. 2000; Hamilton et al., 2000; Ikegami et al., 2001; Page et al., 2002). These studies in terms of measured population level effects 2.3. Analysis are confounded by the burning of vegetation and there is little information on peat fire smoke, individual components within SUMMA canister samples were analysed using USEPA TO-14 smoke and measured human exposure. method. The samples were quantified against a four point calibra- The aim of this work was to characterise the constituents of tion curve with USEPA TO-14 calibration mixture at 0, 0.84, 8.4 and peat smoke as the first step in determining the potential health 16.8 ppb v/v. Several samples exceeded the calibration range and risks associated with exposure to the burning of organic soils in a re-sampling of diluted samples was undertaken. drying environment and where residential development was being impacted. Opportunistic downwind sampling for VOCs and partic- 2.4. Particulate sampling ulate matter (PM10, particles with a size diameter of <10 lm; PM2.5, fine particles with a size diameter of <2.5 lm and PM1, ul- An Osiris Airborne particle sampler (Turnkey Instruments Ltd.) tra fine particles with a diameter of <1 lm) was undertaken during was deployed 400 m west of Lake Neerabup and 200 m north of two peat fires in 2004 and 2005/2006 in the northern metropolitan Menchetti Road. The Osiris is an optical particulate analyser capa- area of Perth, Western Australia. ble of indicating PM10, PM2.5 and PM1 concentrations at a resolu- tion of 0.1 micrograms per cubic metre.