Environment International 68 (2014) 16–24

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Influence of a municipal solid waste landfill in the surrounding environment: Toxicological risk and odor nuisance effects Marinella Palmiotto ⁎, Elena Fattore, Viviana Paiano, Giorgio Celeste, Andrea Colombo, Enrico Davoli Department of Environmental Health Sciences, IRCCS – Istituto di Ricerche Farmacologiche “Mario Negri”, Milano, Italy

a r t i c l e

i n f o

Article history: Received 25 October 2013 Accepted 4 March 2014 Available online xxxx Keywords: Municipal solid waste landfill Landfill gas Human health Toxicological risk Odor nuisance

a b s t r a c t The large amounts of treated waste materials and the complex biological and physicochemical processes make the areas in the proximity of landfills vulnerable not only to emissions of potential toxic compounds but also to nuisance such as odor pollution. All these factors have a dramatic impact in the local environment producing environmental quality degradation. Most of the human health problems come from the landfill gas, from its non-methanic volatile organic compounds and from hazardous air pollutants. In addition several odorants are released during landfill operations and uncontrolled emissions. In this work we present an integrated risk assessment for emissions of hazard compounds and odor nuisance, to describe environmental quality in the landfill proximity. The study was based on sampling campaigns to acquire emission data for polychlorinated dibenzo-p-dioxins and dibenzofurans, dioxin-like polychlorobiphenyls, polycyclic aromatic hydrocarbons, benzene and vinyl chloride monomer and odor. All concentration values in the emissions from the landfill were measured and used in an air dispersion model to estimate maximum concentrations and depositions in correspondence to five sensitive receptors located in proximity of the landfill. Results for the different scenarios and cancer and non-cancer effects always showed risk estimates which were orders of magnitude below those accepted from the main international agencies (WHO, US EPA). Odor pollution was significant for a limited downwind area near the landfill appearing to be a significant risk factor of the damage to the local environment. © 2014 Elsevier Ltd. All rights reserved.

1. Introduction Waste treatment plants are now large complex realities where large amounts of waste materials are treated and where complex biological and physicochemical processes occur in a controlled environment. The impact produced by municipal solid waste (MSW) landfills has received special social and environmental attention in recent decades. Environmental degradation, landscape appearance, heavy traffic load, noise, dusts, fumes and odor emissions, render these facilities environmental stressor with negative impact on life quality of the surrounding communities (Downey and Van Willigen, 2005). Environmental inequality studies show that waste facilities are disproportionally located in the areas where more deprived, or minority groups reside (Faber and Krieg, 2002; Forastiere et al., 2011; Martuzzi et al., 2010), with consequent unequal pollutant exposure. The scientific literature provides some indications of an association between adverse health effects and the residence distance from the landfill site but the level of epidemiological evidence is “inadequate” or “limited” (Porta et al., 2009; WHO,

⁎ Corresponding author. Tel.: +39 02 39014534; fax: +39 02 39014735. E-mail address: [email protected] (M. Palmiotto).

http://dx.doi.org/10.1016/j.envint.2014.03.004 0160-4120/© 2014 Elsevier Ltd. All rights reserved.

2007) with a general lack of consistency in the results for cancer incidence and mortality studies (Jarup et al., 2002; Rushton, 2003). Despite the lack of univocal evidence on the health implications, people are concerned with potential toxic compounds and unpleasant odors produced by landfill gas (LFG) emissions, which include gases generated by the biodegradation of waste and those arising from chemical reactions or volatilization from waste (Environment Agency, 2004a). The LFG emissions mainly consist of methane, carbon dioxide, water vapor and trace amount on non-methane organic compounds (NMOCs) (SoltaniAhmadi, 2000) which include volatile organic compounds (VOCs), hazardous air pollutants (HAPs) and odorous compounds, which in recent years, have been chemically characterized (Davoli et al., 2003; Fang et al., 2012). Communities living nearby landfills are directly exposed to chemicals through inhalation of LFG released during the waste degradation, but also to the combustion products (e.g. dioxins and dioxinlike compounds) that can be generated when LFG is burned in flares or for energy recovery (Environment Agency, 2004a). Ingestion of drinking water obtained from private wells contaminated by leachates, skin absorption and ingestion of contaminated soil particles, or ingestion of home-grown products, are other possible exposure pathways to chemicals.

M. Palmiotto et al. / Environment International 68 (2014) 16–24

Concern is also due to uncontrolled LFG emissions related to the presence of complex mixtures of odorants and irritant air pollutants (Sadowska-Rociek et al., 2009). Although odorous compounds generally represent a nuisance more than a health risk (Fransess et al., 2002), nearby residents are concerned about the potential adverse health impacts for long-term exposure (De Feo et al., 2013). Recently studies have shown that a prolonged exposure to odors can generate unpleasant reactions ranging from emotional stresses such as states of anxiety and unease to physical symptoms (Aatamila et al., 2011), including headaches, eye irritation, respiratory problems, nausea or vomiting (National Research Council Committee on Odours, 1979). All these reactions interfere with daily activities with a great impact of life quality (Heaney et al., 2011). In addition unpleasant odor is more and more often regarded as an environmental concern, that can cause impairment of the quality of the natural environment for any use, altering the ecosystem structure and function. The growing concern for human and environmental well-being, has promoted the necessity for odor impact assessment and consequent odor emission regulation (Nicell, 2009). Many of the studies on health impact of waste treatment plant lack direct exposure information, relying only on residential distance from the site (WHO, 2007). More recently impact assessment study use air dispersion modeling and local weather information to evaluate the exposure to pollutants (Davoli et al., 2010; Forastiere et al., 2011) and to odor (Capelli et al., 2011; Chemel et al., 2012; Sironi et al., 2010) around a landfill site. The main objective of this study was understanding the local environmental impact of a large facility like a landfill. In this work we present an integrated risk assessment study on health impact and the consequences on environmental quality of a municipal solid waste landfill. Air dispersion modeling and local weather information have been considered to estimate the exposure to hazardous pollutants and odor impact, for residents, living near the landfill, in order to evaluate both the potential health risks (carcinogenic and non-carcinogenic) and odor nuisance.

2. Experimental The approach adopted for this impact assessment study involved the site characterization including an identification of the principal emission sources of pollutants and odor, the analytical measurements of the pollutants emitted, the distribution within the environmental media by an appropriate air dispersion model, the identification of sensitive receptors that might be involved, the exposure assessment for the different exposure pathways and, finally, the toxicological evaluation and risk characterization (Environment Agency, 2004b).

2.1. Site characterization This study has been conducted on a hilly isolated area of central Italy that includes small municipalities located few kilometers from the municipal solid waste landfill. The landfill is located in a deep valley completely isolated from the soil by a natural layer of clay. It consists of an exhausted site built in 1986 and closed in 2001 with a capacity of 4,329,254 m3 and an operating site, built in 2001. The surface of the exhausted site is completely covered with natural vegetation while the operating site is covered daily with layers of clay. The landfill receives only non-hazardous waste and the actual volume is 8,877,447 m3 with a final potentiality of 9,465,447 m3. The plant has a leachate collection and removal system with uncovered leachate lagoon, a composting plant with scrubber and fabric filter and a landfill gas extraction system that conveys the LFG to four engines for electricity generation or, alternatively, to flares for burning.

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2.2. Pollutant emissions For this study we considered the following pollutants: benzene, vinyl chloride monomer (VCM), polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs) and polycyclic aromatic hydrocarbons (PAHs). They have been selected because their presence in landfill emissions has been well documented and for their toxicological properties and/or environmental persistence and bioaccumulation (WHO, 2000). The emission sources identified were both the diffusive emissions from landfill surface and the point emissions from flares and engines. The aquifer is absent and leachate migration into underlying ground zones has been supposed to be negligible due to the adoption of high density polyethylene (HDPE) geomembranes as bottom barriers and mainly for a 200 m deep clay layer. We considered three different diffusive emission zones (DEZ), which have been characterized by different types of capping: the first (DEZ-1) has a final capping covered by vegetation. The second and the third areas are the temporary capped surfaces of freshly tipped municipal solid waste (DEZ-2) and the landfill side slopes (DEZ-3), for an overall extension of 214,208 m2 (Fig. 1). Vinyl chloride can be formed from waste as a degradation product of chloroethylene solvents (US EPA, 2002a) whereas benzene can be released directly from the waste (IPCS, 1993). Because of their origin, they have been measured in surface emissions with a depression sampler from the LFG collection tube, which conveys all LFG formed by wastes to engines, using Nalophan™ bags (Max Ramp AG, Switzerland), in accordance with the European norm EN 13725:2003. The sample has been analyzed by solid phase micro extraction (SPME) technique and the extraction has been performed at 22 °C for 25 min with a 50/30 μm DVB/CAR/PDMS triphasic fiber (Supelco). The analysis has been carried out by gas chromatography–mass spectrometry (GC/MS) by using an Agilent 5975C Mass Spectrometer interfaced to an Agilent 7890A GC. Quantitative determinations were performed by the isotope dilution method by comparison with a calibration curve built with 2H-internal standard. Benzene and VCM concentrations and LFG emission data over the landfill surface have been used to estimate benzene and VCM emissions from the landfill, assuming that the flow of pollutants emitted was directly proportional to the loss of LFG, without taking into account the possible effects of abatement from the covering layer of the landfill. LFG diffusive emission data were obtained during a 1-week sampling campaign, performed in June 2008, during calm, sunny days. Temperature was 16.8 ± 5.3 °C and pressure 1009 ± 4.1 hPa (mean ± SD) during the sampling period. Sampling has been performed in 93 different points on the landfill, using a systematic square grid sampling scheme. A number of 75 sampling point was defined following USEPA recommendations (Winegar and Keith, 1993) for the isolation flux chamber operations and it has been adapted to the most convenient number (93 total final samples) due to landfill shape irregularities. PCDD/Fs, DL-PCBs and PAHs have been measured in the flare and engine emissions. For each emission source, a 16-h composite sample has been collected during standard working procedures, in two consecutive days. Flare sampling temperature was 850 °C, while engine emission has been sampled at 140 °C. According to the UNI EN1948-1:2006 procedure, a mixture containing 0.4 ng of 1,2,3,7,8 PCDF and 1,2,3,7,8,9 HxCDF and 0.8 ng of 1,2,3,4,7,8,9 HpCDF has been added during the sampling procedure. PCDD/F analysis in emissions has been performed by using standard official methods (UNI-EN 1948-2:2006 for PCDD/Fs in torch emissions) adding a surrogate containing 0.4 ng of 13C12 tetra-, penta- and hexaCDD/Fs and 0.8 ng of 13C12 hepta- and octa-CDD/Fs. PCB analysis has been performed by adding a surrogate containing 1 ng of each congener.

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Fig. 1. Municipal solid waste landfill: 1: Exhausted site, 2: Operating site, 3: Flares and engines, 4: Composting plant, 5: Leachate lagoon and Diffusive Emission Zone (DEZ).

PAH analysis has been performed by using standard official methods (M.U. 825:89 Man. 122 Part. III for PAHs) adding a surrogate containing 50 ng of each congener. A MAT 95 XP Mass Spectrometer Thermo Finnigan (Thermo Fisher Scientific) coupled with a TRACE GC 2000, was used for PCDD/Fs and DL-PCBs determination and by an Agilent 5973 Mass Spectrometer interfaced to an Agilent 6890 GC was for PAHs determination. Quantification of each analyte has been carried out by using the isotopic dilution method. Limits of detection (LOD) have been determined by applying a signal to-noise of 3. PCDD/F, DL-PCB and PAH emission rates have been estimated by using the measured concentrations and the emission air flow from flare and engine. Engine and flare emission data were obtained during sampling campaigns performed respectively in March and in April 2009. 2.3. Odor emissions The odor sources considered were the diffusive emissions from the landfill surface (DEZ 1-3), and the leachate lagoon, the point emissions were the scrubber and fabric filter stacks. Sampling of landfill surface and composting plant has been carried out by collecting LFG and odorous air sample with Nalophan™ bags. For the passive surface of the leachate lagoon, sampling has been performed by using a wind tunnel system (Frechen et al., 2004; Jiang et al., 1995). Briefly, the wind tunnel has been positioned over leachate and a neutral air stream has been introduced at known velocity inside the hood, simulating the wind action on liquid surface. The odorous air sample, at the wind tunnel exit, has been collected with Nalophan™ bags for olfactometric analysis. Odor concentration, expressed in European odor units per cubic meter (ouE/m3) has been determined by dynamic olfactometry using an olfactometer TO8 (ECOMA GmbH, Germany) in conformity with the European norm EN 13725:2003.

In order to characterize the environmental emission, the odor emission rate (OER) associated with each odor source, and measured in ouE/s, has been estimated. In particular the OER from landfill surface has been calculated by multiplying the LFG emission rate for odor concentration in LFG samples, considering the specific emitting surface. Emission air data from scrubber and fabric filter and odor concentration have been used to calculate odor emission rate from the composting plant. The evaluation of odor emission from leachate lagoon has been carried out by estimating the specific odour emission rate (SOER), expressed in ouE /m2/s. This has been obtained with the wind tunnel by multiplying the odor concentration measured for the flow rate of the inlet air and dividing it by the base area of the central body of the hood. The OER was calculated by multiplying the SOER for the emitting surface (m2) (Sironi et al., 2006). All the odor concentration measurements have been conducted within 30 h after sampling.

2.4. Atmospheric dispersion modeling and identification of the receptors Pollutants and odor concentrations at the receptors have been estimated by using AERMOD, a steady-state plume atmospheric dispersion model developed by the US Environmental Protection Agency (US EPA, 2002b). It consists of two input data processors: AERMET, a meteorological data preprocessor that incorporates air dispersion based on planetary boundary layer turbulence structure and scaling concepts, and AERMAP, a terrain data preprocessor. This model is used to predict the concentration under all weather conditions from different types of sources (diffusive and point sources) and across different terrain conditions including receptor location. The model has been used with a graphical interface, ISC-AERMOD View (Version 5.8.1) (Lakes Environmental Software, Waterloo, Ontario,

M. Palmiotto et al. / Environment International 68 (2014) 16–24

Canada), and the modeling has been evaluated on a grid domain of 9 × 9 km2 with spatial resolution of 1000 m. Site-specific inputs for the model (Tables 1 and 2) have been elaborated by using meteorological (wind speed and direction, ambient temperature, cloudiness) and terrain data, to estimate pollutant and odor air concentrations and pollutant soil depositions in correspondence to five sensitive receptors identified near the landfill. These receptors, A, B, C, D and E (Fig. 2) are small towns of no more than 3200 inhabitants, with the exception of E, the closest to the landfill, which is a rest area with no permanent residents. Their distances from the landfill are 6 km for A, 5.5 km for B, 2 km for C, 8.5 km for D and 0.8 km for E. The transport and relapse of pollutants to these receptors have been modeled by considering the different nature of their processes of formation and emission. In particular, benzene and VCM, which occur into the vapor-phase, have been modeled as a gas, whereas PCDD/Fs, DL-PCBs and PAHs, which occur both into vapor and airborne particle-bound phase, have been modeled considering both transport mechanisms for dispersion and ground deposition. The transport and total deposition of the particle-bounded dioxins has been evaluated with AERMOD Standard Method 1 (US EPA, 2011a). Soil concentrations have been calculated as the sum of dry and wet deposition throughout the year, assuming a top layer of 25 cm, and an average soil density of 1040 kg/m3. All the hourly meteorological data were provided by the nearby city airport, located at a distance of about 30 km from the landfill, and were related to the year 2007. This is the nearest station with available a complete meteorological data set, including cloud cover percentage data, required for the model. The landfill runs a small meteorological station with wind direction and velocity, pressure, temperature and relative humidity sensors, but lacking all other necessary parameters to run the AERMOD model. After a comparison of wind data between the two data sets, as the data coming from the local station was not validated, we decided to use public, validated data, coming from the airport databank. Discrepancies were less than 20% for wind data. As the model does not allow the use of wind calm (wind velocity = 0 m/s) these values have been replaced with the value of 0.3 m/s (Alberta Environment, 2002). 2.5. Exposure pathways In order to estimate human exposure to pollutants, we have been considering the following exposure pathways: inhalation, dermal absorption and ingestion of contaminated soil particles, as well consumption of home-grown vegetables. Inhalation has been considered for all pollutants under investigation, whereas soil dermal contact and soil ingestion (hand-to-mouth transfer) have been considered only for PCDD/ Fs, DL-PCBs and PAHs because of the gas- and solid-phase partitioning; finally, ingestion of home-grown vegetables has been considered for PCDD/Fs and DL-PCBs only, because of their high potential to bioaccumulate and biomagnificate along the food chain. Exposure has been considered separately for children (1–6 years) and adults. Children are at a higher risk than adults for exposure to hazardous substances emitted from waste sites. They spend more time in the outdoor environment and they might breathe higher concentrations

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of dust, soil, and heavy vapors close to the ground, because of their height. They are also smaller, resulting in higher doses of chemical exposure per body weight (US EPA, 1992). The magnitude of exposure (dose) has been calculated by maximum daily intake (MDI), for risk characterization of non-cancer effects, and by chronic daily intake (CDI) for cancer risk characterization. The following general equations have been used: MDI ¼ C x CR x EF x ED=ðBW x ATÞ

ð1Þ

CDI ¼ C x CR x EF x ED=ðBW x LTÞ

ð2Þ

where C: concentration of chemical in the environmental media, e. g., in air (mg/m3), in soil (pg/kgsoil), calculated by AERMOD; CR: inhalation (m3/day), ingestion (mg/day) or dermal contact rate (mg/cm2-event); EF: exposure frequency (365 days/year); ED: exposure duration (24 years for adults and 6 years for children); BW: body weight (70 kg for adults, 15 kg for children); AT: averaging time (24 years for adults and 6 years for children); LT: lifetime (70 years). For cancer effects, where the biological response is described in terms of lifetime probability, AT has been replaced by LT with the value of 70 years (US EPA, 2011b). 2.5.1. Inhalation Inhalation exposure to PCDD/Fs, DL-PCBs, PAHs, VCM and benzene has been estimated by using an inhalation rate (CR) of 20 m3/day for adults and 9 m3/day for children, derived from those proposed in EPA methodology (US EPA, 2011b). 2.5.2. Ingestion of soil Adults may ingest soil inadvertently that adhere to food or their hands during gardening activity whereas children may ingest significant quantities of soil due to their tendency to play on the outdoor grounds and to mouth objects or their hands. The ingestion of soil has been calculated by using an ingestion rate (CR) of 100 and 200 mg/day for adults and children respectively, derived from EPA (US EPA, 2011b). 2.5.3. Dermal absorption from soil Dermal exposure for adults and children has been calculated by multiplying the chemical soil concentration (C) by the extent of skin surface area exposed (adults 3190.5 cm2; children 3587.6 cm2) and the rate of absorption of the chemical CR (1 mg/cm2-event) (US EPA, 2007). 2.5.4. Ingestion of homegrown products PCDD/Fs and DL-PCBs may be absorbed from soil by below ground vegetation or deposited from air to surface of the above ground vegetation. Exposure to vegetation has been estimated by considering, for below ground vegetation, an intake rate (CR) of 0.01367 kg/day for adults and 0.0748 kg/day for children while, for above ground vegetation, 0.1578 kg/day and 0.0761 kg/day for adults and children

Table 1 Pollutants input data for AERMOD model.

DEZ-1 DEZ-2 DEZ-3

Flares Engines *WHO TEQ, **B[a]P eq.

Area (m2)

Diameter (m)

LFG emission rate (m3*m2/s)

VCM emission rate (g/s)

Benzene emission rate (g/s)

160,287 28,191 25,730

226 95 90

6.42 × 10−8 2.18 × 10−6 8.67 × 10−7

1.82 × 10−5 1.09 × 10−4 3.94 × 10−5

2.95 × 10−5 1.77 × 10−4 6.39 × 10−5

Height (m)

Diameter (m)

Emission rate (m3/s)

PCDD/F, DL-PCB⁎ rate (g/s)

PAHs⁎⁎rate (g/s)

6 4

2 4

0.43 1.37

1.88 × 10−12 4.61 × 10−11

3.57 × 10−7 2.24 × 10−8

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M. Palmiotto et al. / Environment International 68 (2014) 16–24

Table 2 Odor input data for AERMOD model.

DEZ-1 DEZ-2 DEZ-3 Leachate lagoon

Scrubber Fabric filter

Area (m2)

Diameter (m)

LFG emission rate (m3*m2/s)

Odor concentration (ouE/m3)

Odor emission rate (ouE/s)

160,287 28,191 25,730 1000

226 95 90 18

6.4 × 10−8 2.2 × 10−6 8.7 × 10−7 –

245,000 245,000 245,000 24,500

3206 15,223 5403 685,000

Flow (m3/h)

Diameter (m)

Emission rate (m3/s)

Odor concentration (ouE /m3)

Odor emission rate (ouE/s)

30,000 30,000

2 2

2.65 2.65

720 810

6000 6750

respectively (US EPA, 2007). The equations to calculate the chemical concentration in below ground vegetation and in above ground vegetation have been reported in the Supplementary Data. 2.6. Toxicological evaluation and risk characterization Risk for cancer and non-cancer effects has been estimated by combining the exposure results with toxicological parameters derived from the main international agencies for human health and environment protection reported in Table 3. For non-carcinogenic effects, the health risk assessment has been based on the hazard index (HI) concept, as the following: HI ¼ ðMDI=RfDÞ

ð3Þ

where RfD is the reference dose (mg/kg BW-day), which represents an estimate of daily dose of a substance to which human population

(including sensitive subgroups) can be exposed for all the lifetime period without any appreciable risk to develop deleterious health effects (US EPA, 1988). If HI ≤ 1, the risk is considered acceptable. For carcinogenic effects, the risk (R) is defined as the probability to develop cancer during a lifetime, and has been calculated by using the equation: R ¼ CDI x SF

ð4Þ

where SF (slope factor, kg BW-day/mg) represents the chemical's carcinogenic potency for unit dose. It is defined as an upper bound, approximating a 95% confidence limit, on the increased cancer risk from a lifetime exposure to an agent. This estimate, expressed in units of proportion (of a population) affected per mg/kg-day, is generally reserved for use in the low-dose region of the dose–response relationship, that is, for exposures corresponding to risks less than 1 in 100 (US EPA, 2011b).

Fig. 2. Localization of the five sensitive receptors (A, B, C, D, E) near the municipal solid waste landfill (MSWL) and the wind rose for the site.

M. Palmiotto et al. / Environment International 68 (2014) 16–24

For B, C, and D receptors, all values are less than 1 ouE/m3 and the annoyance potential in the exposed population is considered nonsignificant. Considering the results of OERs calculations for each odor source reported in Table 2, the major contribution to odor emission is given by the uncovered leachate lagoon with an OER of 685,000 ouE/s. It is worth to note that this odor emission source is from one to two orders of magnitude higher than the other single sources, accounting for over 96% of the total OER (709,000 ouE/s). Also this emission rate was consistent with other data available (Drew et al., 2007; Sironi et al., 2005).

Table 3 Toxicological values used to calculate the risk assessment for all pollutants. Pollutants

RfD (mg/kg BW-day)

RfC (mg/m3)

SF (mg/kg BW-day)−1

PCDDs (2,3,7,8-TCDD) PAHs (Benzo[a] pyrene) VCM Benzene

RfDing: 7 × 10−10 ⁎⁎

Not derived

RfDinh: 3.14⁎⁎⁎⁎

Not derived

Sfing: 1.0 × 106⁎⁎ Sfinh: 1.30 × 105⁎ Sfinh: 7.32⁎ Sfing: 7.30⁎⁎⁎ Sfinh: 3.08 × 10−2⁎ Sfinh: 2.73 × 10−2⁎

−7⁎⁎⁎

RfDinh: 2.86 × 10 RfDinh: 8.55 × 10−3⁎

0.1⁎⁎⁎ 0.3 ⁎⁎⁎

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⁎ISS-INAIL, 2012; ⁎⁎US EPA, 2010; ⁎⁎⁎US EPA, 2011c; ⁎⁎⁎⁎ISS-ISPESL, 2009.

3.2. Health risk assessment 3. Results and discussion 3.1. Dispersion modeling results PCDD/Fs, DL-PCBs, PAHs, VCM and benzene concentrations have been reported in Table 1 in the Supplementary Data. Table 4 reports the annual average air concentration and soil deposition of pollutants, for each receptor, as from AERMOD output. PCDD/F and DL-PCB air concentrations and soil depositions have been here reported as toxic equivalents (TEQ) (Van den Berg et al., 2006) and PAHs concentration as benzo[a]pyrene equivalents (B[a] P eq.) (Nisbet and LaGoy, 1992). The highest air concentrations estimated for VCM and benzene at receptors reflect their higher emissions from the landfill, as reported in Table 1. Pollutant emissions are higher than those estimated by Davoli et al. (2010) for a municipal solid waste landfill in Sicily (VCM = 5.07 × 10− 4 g/s; PAHs = 1.50 × 10− 9 g/s; PCDD/Fs = 7.60 × 10− 13 g/s). The wind-rose for the site (Fig. 2) shows that predominant wind direction was from the East, with a frequency of 20% (annual average), while the secondary wind direction was from the South East, with a frequency of 15%. The percentage of calm hours was 2.22%. Wind direction supports that the high pollutant air concentration and soil deposition occurred at the North-West side of the landfill. As a result the highest values have been always detected at the small town A (1300 inhabitants; 6 km from the landfill) and at the rest area E (0.8 km from the landfill) whereas the lowest concentrations were measured at the town B (2500 inhabitants; 5.5 km from the landfill) (Table 4). Odor diffusion has been modeled by AERMOD and is reported in Fig. 3. The odor concentrations have been plotted as 98th percentile of hourly averages of odor concentration during the year, as described in IPPC H4 (Integrated Pollution Prevention and Control) guidance (Environment Agency, 2002, 2011 Additional Guidance) and in guidelines of the Italian Region of Lombardia (Lombardy Region, Official Gazzette, 2003 and 2012). The figure reports the isopleths of the peak odor concentration values, on a yearly basis in a scale from 1 ouE/m3 to 12 ouE/m3. The highest odor concentration values have been detected at the receptors A and E, with values respectively of 4.5 ouE/m3 and greater than 12 ouE/m3. At these receptors the odor concentrations exceed the 1.5 ouE/m3. This value is reported as an “indicative criterion” by IPPC H4, for more offensive odors as a “reasonable cause of annoyance”.

The exposure doses (MDI and CDI) and health risk (HI and R) estimated for children and adults, at the receptors, are reported in Table 5. The results of exposure assessment showed that for all pollutants considered, the MDI is always higher in children than in adults, because of their lower body weight. When comparing the individual pollutants considered, the higher exposures are due to VCM and benzene inhalation (Table 5). For PCDDs, PCDFs and DL-PCBs, non-carcinogenic and carcinogenic risk has been evaluated for inhalation, soil ingestion, soil dermal contact and ingestion of homegrown products. Health effects of these compounds, range from immunotoxicity, reproductive disorders (Mocarelli et al., 2008) developmental effects (Miettinen et al., 2005) and cancer induction in different organs (Fingerhut et al., 1991). Table 6 shows the doses of exposure, as MDI and CDI, and risk assessment results, as HI and R, due to cumulative simultaneous exposure for all pathways considered. The HI is always higher at E and A receptors and in children compared to adults, but its value is always lower than the maximum acceptable level for a non-carcinogenic effect (HI ≤ 1). Cancer risk varies between 2.2 × 10−9 (2.2 expected cases out of 1 billion exposed) at receptor B, to 1.4 × 10− 8 (1.4 expected cases out of 1 hundred million) at receptor E. These risks are, respectively, 103 and 102 times lower than 1 expected case out of 1 million (R b 1 × 10−6) that are established acceptable values in Italy (D.Lgs. 152/2006; D.Lgs. 4/2008). For PAHs, cancer and non-cancer risk has been evaluated for inhalation, soil ingestion and soil dermal contact. Non-cancer effects due to PAH exposure involve primarily pulmonary, gastrointestinal, renal and dermatologic system, whereas lung, skin and bladder cancer is associated with occupational exposure (ATSDR, 2009). As shown in Table 5, HI values are again lower than 1, indicating a low risk due to these compounds, as well as a low cancer risk (1 out of 10−10–10−11 range). For VCM and benzene, being volatile airborne compounds, inhalation has been considered the unique exposure route used for risk assessment, and the results are reported in Table 5. The liver is the primary target for the non-cancer and cancer effects of VCM inhalation in animals (Til et al., 1983, 1991) and humans (Tamburro et al., 1984). HI and R values for VCM inhalation are significantly lower than those accepted from the main international agencies indicating low risk to incur to liver alterations and liver cancer.

Table 4 Annual average air concentration and soil deposition of PCDD/Fs and DL-PCBs (as WHO-TEQ), PAHs (as B[a] P eq.), VCM and benzene at receptors. Receptor

Air concentration PCDD/Fs, DL-PCBs (pg WHO-TEQ/m3

A B C D E

1.8 3.0 4.3 5.1 2.0

× × × × ×

10−5 10−6 10−6 10−6 10−5

Soil deposition PAHs (pg B[a]P eq./m3)

VCM (pg/m3)

Benzene (pg/m3)

PCDD/Fs, DL-PCBs (pg WHO-TEQ/kg)

0.4 0.1 0.1 0.1 0.3

660 30 40 20 1920

1050 50 70 100 3030

1.7 2.7 7.3 7.3 2.3

× × × × ×

10−3 10−4 10−4 10−4 10−3

PAHs (pg B[a]P eq./kg) 15.6 2.5 6.2 5.9 25.0

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Fig. 3. 98-percentile of hourly averages of odor concentration for a year modeled by AERMOD.

always below 1 and carcinogenic risk is 10− 3 and 10− 2 times lower than 1 expected case out of 1 million, indicating a low risk due to exposure to these compounds considering all possible exposure pathways. Estimated cancer risk is higher than that previously published for a municipal solid waste landfill in Sicily (Davoli et al., 2010), but still 105 and 102 times lower than the acceptable values.

Also for benzene, whose exposure has been associated to bone marrow alteration, immunological effect and leukemia (ATSDR, 2007), HI and R values are low and the risk to incur to adverse health effects is limited. In Table 6 cumulative HI and cancer risk R are reported for every receptor, accounting for all exposure pathways and the simultaneous exposure to all pollutants considered in this study. HI values are

Table 5 Children and adults exposure (MDI and CDI) and health risk assessment (HI and R) for PCDD/Fs, DL-PCBs, PAHs inhalation, soil dermal contact, soil ingestion and ingestion of home-grown products (only for PéCDD/Fs) and for VCM and benzene inhalation. Pollutant

Receptor

MDI (pg WHO-TEQ/kg BW-day)

PCDD/Fs DL-PCBs

A B C D E

6.5 1.1 1.6 1.9 7.1

PAHs

A B C D E

VCM

A B C D E

Children × × × × ×

10−5 10−5 10−5 10−5 10−5

Adults 2.9 4.9 7.0 8.3 3.2

× × × × ×

10−5 10−6 10−6 10−6 10−5

(pg B[a]P eq./kg BW-day) 2.5 3.6 3.7 4.0 1.9

× × × × ×

10−1 10−2 10−5 10−2 10−1

1.2 1.7 1.7 1.9 9.0

× × × × ×

(pg/kg BW-day) 396 18 24 12 1152

A B C D E

630 30 42 60 1818

HI

R

Children 1.6 2.6 3.7 4.5 1.7

× × × × ×

10−5 10−6 10−6 10−6 10−5

Adults

8.3 1.4 2.0 2.4 9.1

× × × × ×

10−5 10−5 10−5 10−5 10−5

3.7 6.1 8.8 1.1 4.0

× × × × ×

10−5 10−6 10−6 10−5 10−5

1.3 2.2 3.2 3.8 1.4

× × × × ×

10−8 10−9 10−9 10−9 10−8

7.9 1.2 1.2 1.3 6.1

× × × × ×

10−11 10−11 10−11 10−11 10−11

3.7 5.4 5.5 5.9 2.9

× × × × ×

10−11 10−12 10−12 10−12 10−11

4.4 6.5 6.5 7.0 3.4

× × × × ×

10−10 10−11 10−11 10−11 10−10

1.4 6.3 8.4 4.2 4.0

× × × × ×

10−5 10−7 10−7 10−7 10−5

6.6 3.0 4.0 2.0 1.9

× × × × ×

10−6 10−7 10−7 10−7 10−5

3.0 1.4 1.8 9.2 8.8

× × × × ×

10−9 10−10 10−10 10−11 10−9

7.4 3.5 4.9 7.0 2.1

× × × × ×

10−5 10−6 10−6 10−6 10−4

3.5 1.7 2.3 3.3 1.0

× × × × ×

10−5 10−6 10−6 10−6 10−4

4.3 2.0 2.9 4.1 1.2

× × × × ×

10−9 10−10 10−10 10−10 10−8

(pg B[a]P eq./kg BW-day) 10−1 10−2 10−2 10−2 10−2

6.1 9.0 9.0 9.8 4.7

× × × × ×

10−2 10−3 10−3 10−3 10−2

(pg/kg BW-day) 188.6 8.6 11.4 5.7 548.6

(pg/kg BW-day) Benzene

CDI (pg WHO-TEQ/kg BW-day)

98.6 4.5 6.0 3.0 286.8 (pg/kg BW-day)

300.0 14.3 20.0 28.6 865.7

156.9 7.5 10.5 14.9 452.6

M. Palmiotto et al. / Environment International 68 (2014) 16–24 Table 6 Cumulative hazard index (HI) and cancer risk (R) for every receptor considering all exposure pathways and all pollutants. Receptor

HI

R

Children A B C D E

1.7 1.8 2.6 3.1 3.4

× × × × ×

10−4 10−5 10−5 10−5 10−4

Adults 7.9 8.1 1.2 1.4 1.6

× × × × ×

10−5 10−6 10−5 10−5 10−4

2.1 2.6 3.7 4.4 3.6

× × × × ×

10−8 10−9 10−9 10−9 10−8

4. Conclusion The study of environmental impact deriving from municipal solid waste landfill is a complex process, requiring an approach that integrates different local information, analytical methods, knowledge of the toxicological properties of the emitted compounds and risk assessment procedures. This paper describes an air quality impact assessment study based on an environmental characterization, with the identification of sources of main known carcinogen emissions, taking into account their diffusion in different environmental media and population exposure considering different pathways. In our study we evaluated the air quality around a landfill site combining information regarding odor emission and nuisance implications and the possible human health effects (carcinogenic and non-carcinogenic) due to chemical exposure. The results of the olfactometric analysis and odor dispersion simulation show that the odor impact might be relevant for a specific downwind area, near the landfill, and that the most problematic odor source is a lagoon where the leachate is stored uncovered. Compared with the indicated odor impact criteria, we identified a potential odor annoyance due to this emission. In order to minimize potential landfill odor impacts, the lagoon has been removed. The health risk assessment carried out in this study indicates that the potential incremental cancer risk, for residents living in the vicinity of the facility, is negligible, and other health effects are not likely to occur. Nevertheless the land degradation at a landfill site tends to give a greater vulnerability of the surrounding environment, the effects of hazards present are more pronounced and the residents are seriously concerned with the environmental impact of landfills, mainly for potential toxic emissions and health-related issues. A deeper knowledge of the real risks associated with these facilities might be a starting point to build more controlled landfills for more constructive dialogs with hosting communities. Appendix A. Supplementary data Supplementary data to this article can be found online at http://dx. doi.org/10.1016/j.envint.2014.03.004. References Aatamila M, Verkasalo PK, Korhonen MJ, Suominen AL, Hirvonen M, Viluksela MK, et al. Odour annoyance and physical symptoms among residents living near waste treatment centers. Environ Res 2011;111:164–70. Alberta Environment. , Preparation of Alberta Environment Regional AERMOD Screening Meteorology data sets. Available at http://environment.gov.ab.ca/info/library/6783. pdf, 2002. ATSDR. Toxicological profile for benzene. Atlanta, Georgia: Division of Toxicology and Environmental Medicine/Applied Toxicology Branch; 2007. p. 30333. ATSDR. Case studied in Environmental Medicine, Toxicity of Polycyclic Aromatic Hydrocarbons (PAHs). Available at http://www.atsdr.cdc.gov/csem/pah/docs/pah.pdf, 2009. Capelli L, Sironi S, Del Rosso R, Céntola P, Rossi A, Austeri C. Olfactometric approach for the evaluation of citizens' exposure to industrial emissions in the city of Terni, Italy. Sci Total Environ 2011;409:595–603. Chemel C, Riesenmey C, Batton-Hubert M, Vaillant H. Odour-impact assessment around a landfill site from weather-type classification, complaint inventory and numerical simulation. J Environ Manage 2012;93:85–94.

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Influence of a municipal solid waste landfill in the surrounding environment: toxicological risk and odor nuisance effects.

The large amounts of treated waste materials and the complex biological and physicochemical processes make the areas in the proximity of landfills vul...
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