4lim-chemical characterization.pmd R.B. Lamorena-Lim and C.M.F. Rosales 17 SCIENCE DILIMAN (JANUARY-JUNE 2016) 28:1, 17-33 Chemical Characterization and Behavior of Respirable Fractions of Indoor Dusts Collected Near a Landf ill Facil ity Rheo B. Lamorena-Lim* University of the Philippines Diliman Colleen Marciel F. Rosales University of the Philippines Diliman _______________ *Corresponding Author ISSN 0115-7809 Print / ISSN 2012-0818 Online ABSTRACT T h e s t u d y a i m s t o d e t e r m i n e t h e i n o r g a n i c a n d o r g a n i c p h a s e s i n airborne par ticulate matter (PM) collected near a landf ill facility. The establishments within the vicinity of the landf ill considered in the study w e r e a j u n k s h o p , a s c h o o l , a n d a m o n e y c h a n g e r s h o p . F r o m t h e elemental analysis using inductively-coupled plasma mass spectrometry ( I C P - M S ) , l e a d a n d c a d m i u m w e r e d i s c o v e r e d t o b e m o r e a b u n d a n t i n the total suspended particulate (TSP) fraction, whereas copper was more abundant in the smaller PM 2.5 . Manganese, arsenic, strontium, cadmium, a n d l e a d w e r e m o r e a b u n d a n t i n t h e P M 10 f r a c t i o n t h a n i n P M 2.5 . T h e results of the chemical characterization were compiled and evaluated in a geochemical modelling code (PHREEQC) to determine the potential speciation of these chemical constituents. Solution complexes of As, Pb, Cd and phthalates, and metal species, such as H 2 AsO3- , Cd 2 OH3+, Pb(OH)3-, were predicted to form by the PHREEQC simulation runs once the end- member components interact with water. The results contribute to the b a c k g r o u n d i n f o r m a t i o n o n t h e p o t e n t i a l i m p a c t s f r o m e x p o s u r e t o airborne PM at workplaces around landf ill facilities. Moreover, the data g a t h e r e d p r o v i d e a b a s e l i n e f o r t h e c h e m i c a l c h a r a c t e r i z a t i o n a n d behavior of chemical constituents of PM possibly present in this specif ic type of environment. Keyword s: Airborne par ticulate matter, landf ill facility, indoor air quality, solution complexes, PHREEQC speciation, respirable fractions Chemical Characterization and Behavior of Respirable Fractions 18 INTRODUCTION Air pollution is almost always considered ambient. However, humans are estimated to spend 70-90% of their time indoors, thus they tend to be more exposed to pollutants present indoors (Raunemaa et al. 1989). The World Health Organization reports that 2 million premature deaths per year are attributed to exposure to indoor air pollution. Indoor air pollution also accounts for up to 4.0% of the burden of disease for low-income countries (World Health Organization [date unknown]). Pollutants may come from combustion sources indoors (e.g. cook stoves), building materials and furnishings, household consumer products, appliances, or outdoor sources (Lamuth 2008). In the Philippines, a number of studies regarding ambient air quality have been performed in the past (Bautista et al. 2014; Pabroa et al. 2011). However, local studies on the characterization of indoor air aerosols and their airborne behavior are still very limited. Published data regarding the exposure of Filipino workers to indoor particulate matter (PM), particularly in the inhalable and respirable mass fractions, are sparse. One of the most abundant pollutants indoors is PM. PM is a mixture of small particles and liquid droplets. The small particles in PM may be made up of several components, such as acids, organic chemicals, dust particles, soil, or metals (US EPA [date unknown]). PM is generally classif ied based on its size, sampling methodology, and cut-off point of the sampler used for its collection. For example, PM with a diameter of 10 μm is called PM 10 , whereas PM with a diameter of 2.5 μm is called PM 2.5 . PM, especially the smaller size fractions, is a health concern because of its capability to enter the respiratory system and cause health issues, such as chronic obstructive pulmonary diseases and reduced lung function for children and adults (W.H.O. Regional Off ice for Europe 2003). Furthermore, toxic metals in PM have been proven to cause acute inflammatory responses. Water-soluble metals, on the other hand, have been observed to affect the cardiopulmonary system (Costa and Dreher 1997). Hence, it is of importance to be able to characterize and identify the toxic metals present in PM. Some sites of concern with respect to indoor air pollution are plastic/electronic recycling/dismantling centers near landf ill facilities. These facilities collect and sort recyclable wastes as prof itable businesses that flourish as an unorganized sector. Due to unsupervised and uncontrolled practices, improper handling techniques may be prevalent in such facilities. These improper handling techniques can bring about serious health risks not only to workers in such facilities but also to local residents. Most of these facilities situated in Metro Manila lack proper R.B. Lamorena-Lim and C.M.F. Rosales 19 equipment to control or diminish pollutant emissions. Hence, the characterization of pollutants in such complex microenvironments is a crucial f irst step in preparing a comprehensive methodology for def ining acceptable indoor air quality in occupational settings in Metro Manila. The flourishing community near Payatas Dumpsite, which is the main controlled and organized waste disposal site of Quezon City, is an appropriate place to initiate the study. The study aims to determine the inorganic and organic phases in airborne PM collected near a landf ill facility. The results of the chemical characterization were compiled and evaluated in a geochemical modelling code to determine the potential speciation of these chemical constituents. Several establishments within the vicinity of the landf ill site were considered in the study. The indoor areas of a junk shop, a school, and money changer shop were selected as the sampling sites. The study will provide data on the prof iles of total suspended particulates, elemental species, and organic phases in airborne PM. MATERIALS AND METHODS Prel iminary Stud ies To assess the presence of toxic metals in indoor air, preliminary analyses of ordinary house dust using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Scanning Electron Microscopy/Energy Dispersive X-ray Fluorescence (SEM/EDX) w e r e p e r f o r m e d . S a m p l e s w e r e c o l l e c t e d f r o m t a b l e t o p s u r f a c e s a n d a i r conditioning systems in different residential and commercial establishments, digested using hot acid (HNO 3 /H 2 O 2 system), and then subjected to ICP-MS (CalEPA 2007). The remaining undigested samples were subjected to SEM/EDX. Indoor Airborne PM Sampl ing For the landf ill samples, PM was collected on Teflon f ilters using the Airmetrics Minivol sampler with a flow rate of 5 L/min. Three fractions were separately collected (PM 2.5 , PM 10 , and TSP) due to the limitation of the sampler (i.e. only one fraction can be collected at a time). At least three trials per fraction and location were performed. No TSP fraction was collected from the money changer shop. The Chemical Characterization and Behavior of Respirable Fractions 20 sampling was conducted for only three hours due to personnel security, from 10 am to 1 pm, and 1 pm to 4 pm. Sampling was performed in three sites, namely a junk shop, a school, and a money changer shop. The sites were chosen based on their 1) distances from the landf ill and 2) sampler and personnel security. Field and instrument f ilter blanks were also obtained prior to each sampling. The f ilters were weighed using a Sartorius ME5-F microbalance with a minimum resolution of 0.001 mg. Mass concentrations are reported in μg/m3, which was calculated using equation (1). After weighing, the f ilters were halved for inorganic and organic phase characterization. conc in μg/m3 = (1) Where volume of air sampled, m3 = flow rate of Minivol length of sampling conversion factor = 0.9m 3 Sample Analysis Half of the Teflon f ilter was set aside for ICP-MS analysis, whereas the other half was further halved for other characterization techniques. One-fourth of the Teflon f ilter was subjected to 1H-NMR characterization. The other one-fourth was stored for a morphological analysis using SEM-EDX (data will not be shown). Microwave- assisted acid digestion using Ethos closed-vessel microwave digester and 18.5% HNO 3 (4% f inal acid concentration after diluting to 50 mL and upon introduction to ICP-MS), following the method of Kulkarni et al. (2007), was employed as the sample preparation technique prior to elemental analysis using ICP-MS. Recovery studies by means of spiking 0.1, 0.2, 0.25, 0.5, 0.75, and 1 mL of 10 ppm multi- elemental standard into different Teflon f ilters and subjecting them to the same digestion method were performed as a check for the extraction method. Seven solutions containing 1 ppb of the multi-elemental standard were prepared and then subjected to ICP-MS analysis for the determination of the method detection limit. A 500-MHz Agilent NMR spectrometer was used for the 1H-NMR analysis. PM samples were dissolved in deuterated chloroform (CDCl 3 ) to obtain the spectra for the nonpolar compounds, while deuterated water (D 2 O) was used to obtain the spectra for the polar compounds. However, due to the limitation of the NMR spectrometer, no quantif ication was performed for the organic components. 5 L min 3 hr 60 min hr 0.001 m3 1 L weight of sample in μg volume of air sampled in filter, m3 R.B. Lamorena-Lim and C.M.F. Rosales 21 Geochemical Modell ing To model the possible speciation and reactions between water and toxic metals in PM, as well as the influence of organic phases on metal speciation, PHREEQC (pH- Redox-Equilibrium, written in C language), a program developed by the United States Geological Survey (USGS), was used. PHREEQC is designed to perform a wide variety of aqueous geochemical equations and is based on equilibrium chemistry of aqueous solutions interacting with minerals, gases, solid solutions, exchangers and sorption surfaces, and one-dimensional transport (Parkhurst and Appelo 2013). Model simulations performed in the study considered the formation of solution complexes and precipitation of solid phases. Measured parameters, such as pH, temperature, % humidity, and relative stoichiometry, were set as variables in different sets of reaction runs. All speciation calculations used the dissolved elemental concentrations (i.e. chemical analyses previously performed). Metals were indicated in their mineral phases and solution species form. Iso-phthalate containing aromatic and short aliphatic constituents was used as the representative for organic phases. The llnl.dat PHREEQC thermodynamic database supplied with the software was used for the analyses. The f irst data block for the input statement describes a solution of water containing the elements Mn, As, Sr, Cd, and Pb. The temperature was also specif ied. Mole fractions of the elements, which were based on the total metal concentration measured with ICP-MS, were also included. The second data block describes the removal of water from the solution, in order to achieve the humidity conditions as measured. The last data block in the run simulates the reaction of an organic component, isophthalate, to the solution under the specif ied humidity condition. The concentration of isophthalate added was based on literature values since no quantif ication of the organic species was performed. RESULTS AND DISCUSSION Prel iminary Stud ies Preliminary results are shown in Figure 1. Among the elements found in the samples, the crustal/naturally found elements are Na, Mg, Al, Ca (Figure 1A), and Ba (Figure 1B). Meanwhile, the non-crustal elements, which are likely associated with anthropogenic activities, are Cr, Mn, Ni, Cu, Zn, Sr, and Pb (Figure 1B). Ca was Chemical Characterization and Behavior of Respirable Fractions 22 the most abundant among the crustal elements. For the non-crustal elements, Zn concentration was the highest for all locations, followed by Mn, Cu, Ba, and Pb. Ni and Cr were present at low concentrations. Figure 1. Total concentration of metals present in airborne PM. (A) Metals associated with crustal fraction and (B) trace metals. T01, T02, T04 – Residential-single- detached houses; T08, T09 – Laboratory; T10 – Restaurant; T11, T21– Residential- Condominium; T17 – Dental Clinic; T19 – Residential. R.B. Lamorena-Lim and C.M.F. Rosales 23 No source apportionment was performed, thus the exact sources of the elements could be determined. However, high concentrations of Zn, in addition to the natural amounts present in the crust, are associated with the wear and tear of vulcanized vehicle tires and the corrosion of galvanic automobile parts (Wahab et al. 2012). Such could also the source of the Zn for the sampling sites since they were located within close range of some roads (Commonwealth Road and Katipunan Road). Similarly, Cu and Mn may originate from both natural and anthropogenic sources. Soil contains natural amounts of Mn and Cu, but anthropogenic sources, such as industrial processes (battery and electronics manufacturing, steel productions, welding and motor vehicle exhaust), that may be present nearby are also possible sources of these elements (Datta et al. 2012; Midander, 2006). In addition, Cu may also result from brake wear. Pb may be part of the road dust as an element adsorbed and continuously resuspended in the upper layers of the soil. Anthropogenic sources of Pb, such as leaded gasoline, lead-based paint, and lead-arsenate pesticides, have long been eliminated from the industry; however, the presence of Pb in the environment may still be attributed to these sources due to the persistence of Pb. Other anthropogenic sources of Pb may also include the manufacture of lead-containing products, combustion of coal and oil, and waste incineration (ATSDR 2014). Ni, on the other hand, may also come from both natural and anthropogenic sources. The natural sources of Ni, which include the weathering of rocks and soils from volcanic eruptions, are unlikely reservoirs in the urban setting. Anthropogenic sources of Ni, such as industrial processes (combustion, incineration, metallurgical operations, Ni production, chemicals and catalyst manufacturing) may be more probable in the urban setting. In addition, mobile sources, such as engine wear and tear and impurities, and engine oil and fuel additives, may also be possible sources of Ni in an urban setting (Galbreath et al. 2003). Possible sources of Cr may include stainless steel, paint pigments, and wood preservatives (Galarpe and Parilla 2014). Moreover, Cr is involved in many industrial processes, such as chromium plating and cement manufacture. It is also used as an additive to anti-corrosion coatings on vehicles (McSheehy 2008). This preliminary study serves to measure the concentrations of metals in areas far from a landf ill facility. Preliminary measurements show that metal concentration is signif icant even in locations distal from the landf ill area. Based on these f indings, analysis of the airborne PM at the landf ill area is deemed important and necessary. Chemical Characterization and Behavior of Respirable Fractions 24 Description of the Main Sampl ing Sites Payatas dumpsite, a 22-hectare open pit, is located in Quezon City, Philippines. It is the largest and oldest solid waste dumpsite in Metro Manila. Many material recovery facilities (junk shops) are also operational along the Payatas Road. A large community of families thrives near the dumpsite, thus facilities, such as schools, small stores, and small commercial establishments, are present within the vicinity of the site. The three chosen sampling sites are as follows: a junk shop, a school (around 1.6 km from the landf ill), and a money changer shop (near Commonwealth road, a main highway in Quezon City). These sampling sites are situated along a busy road (i.e. which garbage trucks use to enter the landf ill facility). Furnishing and f itting conditions, such as air-condition settings, room and ceiling-height sizes, and room content, were variable. Variation in the Organic and Inorganic Components of PM Table 1 summarizes the results obtained from the sampling, while Figure 2 shows a comparison of the weight distribution per PM fraction per location. From the data, it can be observed that the TSP fraction in the junk shop has the highest mass concentration, while the lowest mean for the PM 2.5 fraction was obtained from the elementary school. Moreover, the values obtained from the junk shop display a generally higher trend than the elementary school and money changer, possibly because it is not a fully enclosed (indoor) location. Thus, PM from outside sources (e.g. road dust, fugitive dusts) may have also contributed to the higher mass concentration. The mass concentration is directly proportional to size, because larger particles are heavier and have higher masses. Numerical values obtained from the study, as shown in Table 1, are larger compared to literature values for indoor air in a classroom in Munich during winter time (19.8 μg/m3 PM 2.5 and 91.5 μg/m 3 PM 10 ) (Fromme et al. 2007). Moreover, the measured parameters are higher than those measured in a typical residential environment in Athens, where the mean 24-hour indoor PM 10 concentration is 35 μg/m3 during the warm period and 31.8 μg/m 3 during the cold period (Diapouli et al. 2011). Furthermore, since no guideline values have been set for indoor air PM, 2005 ambient air guidelines set by the World Health Organization were used to compare the values. The guideline values are 10 μg/m3 (annual mean) and 25 μg/m3 (24-hour mean) for PM 2.5 , and 20 μg/m3 (annual mean) and 50 μg/m 3 (24-hour mean) for PM 10 . It should be of immediate concern that the values obtained from the landf ill R.B. Lamorena-Lim and C.M.F. Rosales 25 site are well above the guideline values. However, it is recommended that a longer sampling time be carried out, in order to be able to fully quantify the PM mass concentration for the selected sampling locations. Table 1. Three-hour averages for PM 2.5 and PM 10 in the three locations, namely the junk shop, elementary school, and the money changer shop. N Mean Min Max PM2.5 (μg/m 3, 3-hour average, Junk shop) 3 70.19 57.78 76.67 PM2.5 (μg/m 3 , 3-hour average, Elem. School) 4 45.00 33.89 56.11 PM2.5 (μg/m 3, 3-hour average, Money Changer) 4 77.08 60.00 102.22 PM10 (μg/m 3, 3-hour average, Junk shop) 3 129.44 114.44 143.33 PM10 (μg/m 3, 3-hour average, Elem. School) 4 126.25 98.89 176.11 PM10 (μg/m 3, 3-hour average, Money Changer) 4 105.69 78.33 142.22 TSP (μg/m3, 3-hour average, Junk shop) 4 209.72 187.78 247.22 TSP (μg/m3, 3-hour average, Elem. School) 4 110.00 33.89 176.11 PM 2.5 (Ju nk sh op ) PM 2.5 (E lem . S ch oo l) PM 2.5 (M on ey Ch an ge r) PM 10 (J un ks ho p) PM 10 (E lem . S ch oo l) TS P ( Ju nk sh op ) TS P ( El em . S ch oo l) Figure 2. Mass concentration of PM fraction per location. PM 10 (M on ey Ch an ge r) Chemical Characterization and Behavior of Respirable Fractions 26 (3)MDL = t x S Where t = student’s t-value at 99% conf idence level (t 7 =3.14) S = standard deviation of the seven replicates % recovery = (C s -C)/S x 100 where C s = measured concentration of spiked sample C = measured concentration of unspiked sample (background concentration) S = theoretical concentration of the spiked sample (2) Method Val idation (Closed-vessel microwave-assisted acid d igestion) To assess the accuracy of the method, recovery studies were performed. Percent recovery was calculated according to the following formula (US EPA 1994): Upon the analysis of the spiked samples using ICP-MS, eight out of the 13 elements (manganese, cobalt, nickel, copper, arsenic, strontium, cadmium, and lead) analyzed have acceptable % recovery values (i.e. between 70-130%) for all the concentrations of the spike. To determine the method detection limit (MDL), equation (3) was used, and MDL values calculated for the elements were observed to have acceptable recoveries (US EPA 1994). Inorganic and Organic Characterization of Airborne PM Elemental analysis of the PM fractions allowed the determination of the dominant toxic metals on each fraction. Lead and cadmium were more abundant on the TSP fraction, whereas copper was more abundant on the smaller PM 2.5 . On the other hand, manganese, arsenic, strontium, cadmium, and lead were also present on PM 10 and were more abundant on this fraction than on PM 2.5 . Figures 3-5 show the distribution of toxic metals for different size fractions of PM. 1H-NMR analysis indicates the presence of organic constituents, such as hydrocarbons, from airborne PM. Spectra with similar peaks at 0.8-1.6 ppm and 7.0-7.5 ppm were obtained for all fractions and locations, signifying similar organic compositions for R.B. Lamorena-Lim and C.M.F. Rosales 27 Figure 3. Metal concentrations in TSP fractions collected from sampling sites. (A) Junk shop and (B) elementary school. No TSP fractions were collected from the money changer shop. A B airborne PM present near landf ill areas. Peaks found at 0.8-1.6 ppm indicate the presence of aliphatic groups for all the samples. An additional peak at around 4.7 ppm for the TSP fraction of the junk shop, which was also present in the PM 10 fraction from the elementary school, may indicate the presence of some alcohols. Aromatic groups were also detected, as represented by peaks at 7.2-7.3 ppm (overlapping with the solvent peak, therefore not conclusive) (Figures 6A and 6B). Chemical Characterization and Behavior of Respirable Fractions 28 A B C Figure 4. Metal concentrations in PM 10 fractions collected from sampling sites. (A) Junk shop, (B) elementary school, and (C) money changer shop. R.B. Lamorena-Lim and C.M.F. Rosales 29 Figure 5. Metal concentrations in PM 2.5 fractions collected from sampling sites. (A) Junk shop, (B) elementary school, and (C) money changer shop. A B C Chemical Characterization and Behavior of Respirable Fractions 30 Potential Speciation of Inorganic and Organic Constituents in PM Simulation results show that solution complexes of H 2 AsO3-, HAsO 3 2-, AsO 3 3-, H 3 AsO 3 , Cd(OH) 2 , CdOH +, Cd(OH)3-, Cd2+, Cd 2 OH3+, Cd(OH) 4 2-, Pb(OH) 4 2-, Pb(OH) 3-, Pb 3 (OH) 4 2+, Pb(OH) 2 , Sr2+, and SrOH+ could potentially form when elemental components interact with the surrounding water vapor. Moreover, phases, such as Cd(OH) 2 , Cd (s) , litharge, massicot, monteponite, Pb(OH) 2 , Pb 2 O(OH) 2 , Pb (s) , and PbO:0.3H 2 O, could possibly be precipitated after equilibration. Signif icant formation of isophthalate and protonated Pb-Isophthalate were also identif ied by the simulation runs. On the other hand, Cd-Isophthalate species were found at lower concentrations. A B Figure 6. Small peaks detected for aliphatic and aromatic groups in all PM fractions collected. (A) TSP and (B) PM 2.5 fractions. Both fractions were collected from the junk shop. R.B. Lamorena-Lim and C.M.F. Rosales 31 CONCLUSIONS AND RECOMMENDATIONS The results contribute to the discussion on local issues with indoor air quality in the workplace by providing background information on the potential impacts from exposure to airborne PM around landf ill facilities. The gathered background information provides a baseline data on the chemical characterization and behavior of chemical constituents of PM possibly present in this specif ic type of environment. This places importance on occupational health in workplaces where Filipino workers (especially women and children) are exposed to environmental agents on respiratory health. Signif icant levels of metals were observed from all TSP and respirable fractions. Presence of such metals may be attributed to activities involving the production of such metals. However, since no topographical or meteorological parameters were taken in to account, attribution to anthropogenic sources cannot be made with certainty. Organic phases with aromatic and aliphatic characters were also detected in all airborne fractions. An additional peak for the TSP fraction may also be correlated to the presence of some alcohols. The data gathered from this study will be used for further modeling studies on the speciation of the chemical constituents of PM. The results will also be utilized in developing methods to quantitatively determine the species formed during the simulations. Likewise, the information collected from the characterization of the respirable PM regarding indoor or workplace air quality is important in the assessment of the exposure of the workers in such occupational settings and the determination of its influence on nearby regions. ACKNOWLEDGMENTS The author acknowledges the Off ice of the Chancellor of the University of the Philippines Diliman, through the Off ice of the Vice Chancellor for Research and Development, for funding support through the Outright Research Grants. REFERENCES [ ATSDR] Agency for Toxic Substances and Diseases Registry [Internet]. 2014. Lead: p o t e n t i a l f o r h u m a n x p o s u r e . [ c i t e d 2 0 1 6 M a r c h 0 7 ] . A v a i l a b l e f r o m : h t t p : / / www.atsdr. cdc.gov/substances/toxsubstance.asp?toxid=22. Bautista AT, Pabroa PC, Santos FL, Racho JD, Quiri LL. 2014. Carbonaceous particulate matter characterization in an urban and rural site in the Philippines. Atmospheric Pollution Research. 5(2):245-252. Chemical Characterization and Behavior of Respirable Fractions 32 [CalEPA] California Environmental Protection Agency (US). 2007. 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Available from: http://www.who.int/entity/phe/air_quality_q&a.pdf? u a = 1 . _____________ Rheo B. Lamorena-Lim is an Associate Professor of Institute of Chemistry, University of the Philippines-Diliman. She earned her Ph.D. degree in Environmental Engineering in Korea Advanced Institute of Science and Technology (KAIST) in Daejeon, South Korea in 2011. Her scope of research interest includes carbon dioxide sequestration in geological formations, atmospheric and indoor air chemistry, soil chemistry, soil and waste remediation. Colleen Marciel F. Rosales is an MS Chemistry student at the Institute of Chemistry, University of the Philippines Diliman. She f inished her undergraduate degree in Chemistry, and was an instructor in the same institute for four years. Her research interests include indoor air quality, air quality management, and environmental analytical chemistry.