PM10 and Elemental Concentrations in a Dismantling Plant for Waste of Electrical and Electronic Equipment in Greece

Processing Waste of Electrical and Electronic Equipment (WEEE) causes serious environmental problems, especially when WEEE is processed in uncontrolled conditions. WEEE recycling under controlled conditions consists of the following major steps: disassembly, upgrading and refinement. Disassembly is usually done manually, and, at this stage, certain components (cases, external cables, cathode ray tubes [CRTs], printed circuit boards [PCBs], batteries etc.) are separated. This activity releases coarse and fine particles, which may also contain additional noxious substances, into the atmosphere. The current study determines the concentration of indoor PM10 in a Greek plant for the dismantling and temporary storage of WEEE, based on a short-term sampling campaign. Elemental concentrations in the PM10 have also been determined. Results show that the indoor PM10 concentration in the disassembly area did not exceed the timeweighted average (TWA) for total particles set by Greek legislation or the 8-h TWA for total particles set by the Occupational Safety and Health Administration (OSHA). Nevertheless, these concentrations were higher than those measured in the ambient air of Greek cities. Regarding the measured elements, Zn, As, Br, Pb and Cd were quite enriched in PM10, indicating significant indoor sources. Factor analysis of elements of possible anthropogenic origin showed a clear distinction between cathode ray tubes (CRT) and other possible sources. Finally, the risk assessment for metals of toxicological concern showed a non-negligible lifetime risk for 8-h workers. This is the first report of WEEE indoor air pollution in Greece and its associated origins and effects.


INTRODUCTION
Management of Waste of Electrical and Electronic Equipment (WEEE) has been listed among the priority issues in European and national policies related to waste management (2003/108/EC, 2012/19/EU).WEEE management has become an urgent issue due to substances included in WEEE which are often hazardous as well as due to the increasing amounts of WEEE that are produced worldwide.
WEEE contain a high percentage of metals (approximately 60% w/w) as well as plastics (15%), cathode ray tubes (CRT) and liquid crystal display (12%), mixed materials of metal and plastics (5%) and many others (Makenji and Savage, 2012) which eventually may be released to the environment and become a threat to humans.In addition, dioxins may be formed as the original e-waste components are degraded (Swedish Environmental Protection Agency, 2011) and polybrominated diphenyl-ethers may be released from the surface of these e-products (Gou et al., 2016).The best option, both from an environmental and a recovery efficiency point of view, is to recycle the WEEE; however, the recycling process may also cause serious environmental problems, especially when taking place informally under uncontrolled conditions.Several research works have been published on the uncontrolled recycling of WEEE, and especially on case studies in developing countries (Deng et al., 2006;Leung et al., 2006;Huo et al., 2007;Wong et al., 2007;Leung et al., 2008;Liu et al., 2008;Xing et al., 2009;Gu et al., 2010;Sepúlveda et al., 2010;Chen et al., 2011;Tsydenova and Bengtsson, 2011;Song and Li, 2014;Zheng et al., 2016).
On the contrary, studies on WEEE recycling under controlled conditions in European factories adapted for this purpose are few (Julander et al., 2014;Zimmermann et al., 2014).It is obvious that recycling under controlled conditions is better from a risk perspective for the workers, the local residents, and the environment; nevertheless, risks may occur during these processes as well (Swedish Environmental Protection Agency, 2011).
In this framework, the current study was performed in an organized WEEE dismantling facility in Greece, with the objectives of: (i) determining the PM 10 concentrations, as well as the concentrations of selected elements found in PM 10 , inside a WEEE manual dismantling and temporarystorage plant in Greece; (ii) estimating the possible origin of the different components of airborne particulate matter (PM); (iii) assessing the corresponding health risks for the workers.
This study aims at enriching our knowledge on the state of the art of organized WEEE recycling facilities in developed countries, as well as on the risks and problems that may arise from these activities.Finally, it may act as a database for further similar research in WEEE recycling processes and their environmental impact in Greece.

Study Site and Production Process
The measurement campaign was carried out in a WEEE treatment plant, located in central Greece with a main dismantling area of 1344 m 2 and a maximum capacity of 3000 tn year -1 .The main activities taking place in the treatment plant are manual disassembly of the WEEE and removal of any hazardous substances, according to the Directive 2002/96/EU.The recycling stages in the treatment plant are: a) arrival and sorting of WEEE by category, b) WEEE processing (manual disassembly and remediation for the recovery of selective treatment substances such as PCB, capacitors, batteries, toners and cartridges etc.) and c) temporary storage and shipping to certified companies and treatment plants for further processing.WEEE categories treated in the treatment plant include: a) IT and telecommunications equipment such as PCs, monitors, printers, phones, etc.; b) consumer equipment such as TVs, radio-CD-DVD players, audio equipment, etc.; c) monitoring and control instruments such as smoke and movement detectors, control panels, measuring, weighing or adjusting appliances etc. (WEEE plant, personal communication).

Sample Collection and Analysis
Sampling campaigns were conducted during the months October and November of 2012.Climatological data for this time-period are given in Table 1 (National Observatory of Athens, 2018).The samples were collected in 11 different points in the WEEE treatment plant, 7 of which were located in the main dismantling area of the treatment plant, 2 were located in the offices of the administrative stuff and 2 were located in the area surrounding the treatment plant.A layout of the treatment plant, including the sampling points and the number of sampling dates in each point is shown in Fig. 1.Sampling points have been strategically chosen, in relation to the process that takes place near them.In Point 1, CRT glass remediation takes place; the tube is split into the electron gun part, the neck/funnel glass and the face plate glass.Each part is then further reduced into smaller parts.In Point 2, activities which precede the activities in Point 1 take place, namely dismantling of TV monitors into TV case part and remaining parts.The latter are then divided into CRT part and other subparts.In Point 3, various electronic equipment, small in size such as fans and mixing machines are dismantled.In Point 4, dismantling of PC monitors, CD players and cell phones take place.CRTs deriving from this process are also subsequently transported to Point 1. Photocopiers are dismantled in Point 5. Dismantling of PCBs takes place in Point 7 while Point 6 was next to the static PM sampler (Tecora Echo PM LVS) and the equipment conveyor belt.Points 9 and 8 are within the office spaces of the plant, which are adjacent to the dismantling area.Point 10 is on the outside, next to the back door of the plant, while Point 11 is also outside in the backyard 37 m from the plant.No mechanical ventilation exists in the treatment plant and the offices, and the rooms are naturally ventilated in daytime through open doors and windows.The WEEE treatment plant did not operate in the weekends.
A Tecora Echo PM LVS sampler was used for the gravimetric determination of PM 10 mass concentration in the indoor air of the main dismantling area of the WEEE treatment plant.The sampler operated for 4 hours a day, during working hours.The sampling period was selected such as to prevent overloading of the collected filter samples.The sampler operated at a flow rate of 2.3 m 3 h -1 , in accordance with the sampling procedure standardized in EN 12341: 1998.The samples were collected on Teflon (Zefluor) filters, 47 mm in diameter and with 2.0 µm pore size.In order to determine PM 10 concentrations, filters were equilibrated before and after sampling for at least 24 hours at controlled conditions (20 ± 1°C and 50 ± 5% relative humidity) and were then weighed with the use of a microbalance (d = 0.01 mg).The samples were then analyzed for major and trace elements, by Electrothermal Atomic Absorption Spectroscopy (ET-AAS) and X-ray Fluorescence (XRF).A total number of 10 filters were collected and subsequently analyzed.Details on both analytical techniques are given below.
In addition, two real-time monitors, MIE Thermo Personal DataRAM™ pDR-1000AN and pDR-1200 Particulate Monitors, were used for the determination of PM 10 mass concentration inside and outside the WEEE treatment plant.µΙΕ Thermo Personal DataRAM™ pDR-1000AN was used for the determination of PM 10 mass concentration at seven different sites inside the WEEE treatment plant.The other monitor was used for the determination of PM 10 mass concentration at the other four different sites, two at the offices and two outside the treatment plant.The two monitors were operating 24 h a day, giving data per 30 sec.Raw data collected by the real-time monitors were calibrated based on gravimetric measurements.Specifically, the realtime concentration data recorded inside the dismantling area were averaged over the sampling period of the PM sampler and were compared to the corresponding gravimetric measurements.A very good correlation was observed (Pearson coefficient = 0.82).The linear regression equation that was obtained, was used for the calibration of the indoor concentration data.Ambient real-time concentrations were calibrated based on concurrent gravimetric and real-time measurements conducted in the ambient atmosphere in previous experiments (unpublished data).A different calibration equation was used for indoor and outdoor data, since the aerosol composition and size distribution both play a major role in determining the relationship between gravimetric and real-time measurements and these aerosol properties may vary significantly between the indoor and outdoor environments (Diapouli et al., 2008).

X-ray Fluorescence (XRF)
The collected PM 10 samples were analysed for 19 elements (µg, Al, Si, S, P, Cl, Ca, K, Ti, Mn, Fe, Cu, Zn, As, Br, Sr, Sn, Ba and Pb) by means of energy dispersive X-Ray Fluorescence (ED-XRF).ED-XRF analysis was performed applying a "thin-layer" measurement on Ø 25 mm disks cut from each Teflon filter.Details on ED-XRF instrumentation, calibration method, detection limits and overall precision are provided in Grigoratos et al. (2014).The analytical data were validated using the NIST 2783 Standard Reference Material (Air particulate on filter media) and single-element XRF Calibration Standards obtained from Micromatter™.Duplicate ED-XRF analyses were performed for about 10% of all ambient samples according to standard operating procedures (Grigoratos et al., 2014).

Electrothermal Atomic Absorption Spectrometer (ET-AAS)
The remaining part of the PM 10 filters was analysed by ET-AAS by a Varian 220 spectrometer equipped with a GTA 110 graphite furnace, for the determination of V, Cr, Co, Cd and Ni.Lab and field filter blanks were also prepared and analyzed together with the samples, and the concentrations measured were subtracted from sample measurements (Karanasiou et al., 2005).Details on the analytical procedure followed are provided in Diapouli et al. (2017) and Manousakas et al. (2014).The analytical data were validated using the NIST 1648 Standard Reference Material.Standards for calibration were obtained from Merck and solutions were prepared by adding ultrapure water from a Millipore Milli-Q System.Palladium was used as modifier for Cd (as Pd, 10 g L -1 ) and Mg for V (as Mg(NO 3 ) 2 , 10 g L -1 ).All modifiers were of suprapure grade and were obtained from Merck.Hollow cathode lamps were used as radiation sources for all elements.ET-AAS conditions were carefully optimized for the compensation or elimination of interferences (Karanasiou et al., 2009).Detection limits for the different elements were calculated based on field blank filters and were in the range 0.1 ng m -3 (Cd) to 6.8 ng m -3 (V).

Calculation of Enrichment Factor
In order to calculate the contribution of natural or anthropogenic sources, the enrichment factor was used (Baeyens and Dedeurwaerder, 1991).The general formula to express the enrichment factor (EF) is: where EF is the enrichment factor of element X, Y is the reference element of crustal material, X/Y AIR is the concentration ratio of X to Y in air sample, and X/Y CRUST is the concentration ratio of X to Y in the crust (Mason, 1966).If EF approaches unity, crustal soils are likely the predominant source for element X.If EF is > 5, the element X may have a significant fraction contributed by non-crustal sources (Gao et al., 2002).EF was calculated for 22 elements, Mg, Si, Al, P, S, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, As, Br, Sr, Sn, Ba, Pb, Cd, Cr, with Al used as the reference element for crustal material.Values for crustal material were obtained from Mason (1966).Due to the low number of observations above the limit of quantification, V and Co were excluded from this analysis.

Correlations between PM 10 Values and between elements Found in PM 10
Correlations for 8-h PM 10 mean concentrations (working hours) between dismantling area and office area were explored, using Pearson product-moment correlation coefficient, for the days that simultaneous measurements were available (7 days in total) on SPSS22 (IBM, Armonk, NY, USA).Principal component analysis (PCA) was used to identify the underlying latent factor structure of the PM 10 data for the elements of probable anthropogenic origin that are also of toxicological concern: Mn, Ni, As, Sr, Sn, Pb, Cr and Cd.PCA was conducted using maximum likelihood estimation and oblimin rotation.The assumption of homoscedasticity of variance was assessed with Bartlett's test of sphericity.

Human Risk Assessment for Elements Found in PM 10
Non-carcinogenic health risk assessment for inhalation exposure was calculated for a number of elements of toxicological concern, namely Pb, As, Cd, Ni, Sn Cr and Mn, according to Li et al. (2013).Inhalation exposure concentration was calculated according to the formula RfDs for Ni, Mn, Cd, Cr and As were derived from IRIS database (USEPA, 2017); RfD for Pb was the one used in Qu et al. (2012); Sn RfD was derived from the subchronic MRL for inorganic tin (ATSDR, 2005).
Finally, the hazard index (HI) was calculated as the sum of HQs: where i corresponds to different contaminants.HI ≤ 1 indicates no adverse health effects whereas HI > 1 indicates likely adverse health effects.Carcinogenic risk assessment was performed for the metals As, Ni, Cr and Cd according to the formula (Lau et al., 2014): where IUR = inhalation unit risk from IRIS database (USEPA, 2017) and where AT = averaging time (613,200 h) In order to minimize the uncertainties associated with the calculation of risk, Monte Carlo simulation technique was used, considering 1,000 iterations.A probabilistic distribution of HQ values and of cancer risk was obtained as simulation result.

PM 10 Concentrations
The analysis of the collected data showed that the WEEE dismantling activities resulted in elevated mass concentrations in the indoor environment based on the pDR continuous measurements.8-h indoor PM 10 mass concentrations during working hours are summarized in Fig. 2(b).
While there are no universally accepted upper limits for PM 10 mass concentration for the indoor air of different environments, there are quite a few recommendations for Occupational Exposure Limits (OELs).According to the Greek legislation, TWA concentration for total particles emitted during the production phase should not exceed 100 × 10 3 µg m -3 .This limit involves both the indoor and the outdoor environments (Glytsos et al., 2013).Furthermore, OSHA 8-h TWA limit is 15 × 10 3 µg m -3 for total particulate matter.As such the indoor PM 10 concentration in the dismantling area (based on the 8-h average concentrations) did not exceed the above limits.Kim et al. (2015) conducted a U.S.-based study on an e-waste recycling facility that utilized mechanical processing in three lines.In this study they found that the PM 10 concentration in two size reduction lines ("low density e-waste" and "high density e-waste", employing various size reduction methods) was 439 ± 233 µg m -3 and 543 ± 67 µg m -3 respectively, while in CRT disassembly line the respective concentration was 535 ± 165 µg m -3 .In general, the PM concentration is expected to be increased when size reduction operations are performed comparing to dismantling operation (Tsydenova and Bengtsson, 2011).
Our results of the 8-h PM 10 mean concentration are comparable with the results of Fang et al. (2013) who measured an average PM 10 concentration of 360.4 µg m -3 in the mechanical workshop of a licensed and permitted enterprise of waste TV recycling, located in the industrial zone of Shanghai, processing 740,000 television sets per year.Xue et al. (2012) reported slightly lower PM 10 levels (202.0 µg m -3 ) in a PCB qualified recycling plant located in Jiangsu, China, processing up to 600 kg PCBs per hour.Song et al. (2015) measured Total Suspended Particles (TSP) concentrations in the CRT and PCB workshops of a mobile waste recycling plant processing up to 48,000 units per year, equal to 246.5 µg m -3 and 650.7 µg m -3 , respectively.
It is expected that PM concentration will be increased during working hours in relation to non-working hours and weekends inside the recycling plant.The daily periodicity inside the dismantling area is clearly depicted with the concentration increasing in the beginning of the shift at 07:00 in the morning and decreasing after the end of the shift at 16:00 in the afternoon as shown in Fig. 3.The results indicate that there is no clear association between the activity that was taking place and the variability of PM 10 concentrations, which however were different from day to day.Consistent with the results of Kim et al. (2015), the fluctuations of PM 10 were associated with both PM 10 emissions and resuspension of dust, since forklifts and collection bins were in constant motion during working hours.
Regarding the PM 10 levels in the administrative office, the values were lower but comparable to other occupational areas of increased PM 10 concentrations in Greece, such as offices or mixed office-lab rooms and photocopying places in Thessaloniki (75 ± 43 µg m -3 ) (Gemenetzis et al., 2006) and to concentrations found in school classrooms in residential areas in Athens (80-100 µg m -3 ) (Diapouli et al., 2007).No correlation was found between daily 8-h PM 10 mean concentrations in main dismantling area and in offices (R = 0.74, p = 0.072).
Since the main equipment in the administrative office were two computers and smoking was not permitted it can be assumed that the main source of PM 10 was the resuspension of dust from people's movements.No direct comparison can be made with the outdoor PM 10 concentration, since indoor and outdoor concentrations were measured on different days.In any case, the plant is situated in the countryside, next to a fairly busy National Road that connects two mainland cities in central Greece, both of which have exhibited elevated PM 10 due to increased car traffic (Papamanolis, 2015).It is possible that some enrichment of offices and the dismantling area with outdoor PM 10 due to traffic may have taken place.However, wind velocity was quite low for the dates of measurements as shown in Table 1.

PM 10 Elemental Composition
The elemental concentrations associated to indoor PM 10 are given in Table 2.The OSHA, NIOSH and Greek  Legislation Permissible Exposure Levels (PELs) of selected elements are presented in Table 3 and it can be seen that all elemental concentrations (based on 4-h average values) were lower than the corresponding 8-h TWA limit values.Ca was by far the most abundant element in the PM 10 size fraction (~60 µg m -3 ), followed by Fe (~13 µg m -3 ) and Si (~9 µg m -3 ).Si, Al, Mg, Fe, Ca, Ti and P are elements included in the earth's crust composition (Mason, 1966) so it may be assumed that these elements were most likely derived from resuspension of dust due to indoor human activities and the forklift's movement.
Regarding elements that are commonly found in WEEE, namely Pb, Ni, Cu, Cr, Mn, As and Zn (Andreola et al., 2005;Mostaghel and Samuelsson, 2010;Nnorom et al., 2011;Tsydenova and Bengtsson, 2011;Makenji and Savage, 2012;Dai et al., 2015), these were also detected in PM 10 as shown in Table 2 but were all below the permissible exposure limits set by OSHA, NIOSH and the Greek legislation.
Consistent with other studies (Xue et al., 2012;Julander et al., 2014;Lau et al., 2014;Kim et al., 2015), Zn concentrations were the highest of all WEEE-related elements and Pb was the second highest.Concerning Pb, Cu, Mn, Fe, Ni, Ba and Cr concentrations, our results were within the range of values reported in Julander et al. (2014), Kim et al. (2015) Lau et al. (2014) and Xue et al. (2012).
Focusing on the comparison of elemental concentrations between indoor PM 10 in the WEEE dismantling plant and typical ambient levels, As concentrations in indoor samples were 140 times higher and Pb concentrations were 40 times higher than these measured in the ambient air of the city of Volos (Emmanouil et al., 2017).Significantly increased were also the indoor concentrations of Cu, Ni, Zn, Cd (> 10 times) and of Cr (> 5 times).Comparing with ambient elemental concentrations in the city of Thessaloniki, Greece (Diapouli et al., 2017), Pb concentrations were found 150 times higher and As was 140 times higher.Pb is commonly the most enriched element in WEEE processes in comparison to ambient air concentrations (Kim et al., 2015).
The enrichment factor with respect to the earth's crust composition was calculated for 22 elements (Mg, Si, Al, P, S, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, As, Br, Sr, Sn, Ba, Pb, Cd, Cr) found in the samples of indoor PM 10 in the WEEE recycling plant.Αl was used as the reference element based on the chemical composition of the earth crust (Mason, 1966).The results (Table 4) suggest that P, S, Cl, Ca, Ni, Cu, Zn, As, Br, Sr, Sn, Pb, Cd and Cr were enriched indicating sources other than resuspension of dust; it can therefore be assumed that these elements derive    (Andreola et al., 2005) while Pb is also commonly-but not exclusivelyfound in the back funnels of CRTs (Mear et al., 2007).Pb is still also found in PCBs (Tsydenova and Bengtsson, 2011), but in reducing trends (Lau et al., 2014;Holgersson et al., 2018), hence its negligible contribution to the two other components here.Cd is also found in older types of  , 2003).Cd is also a material in PCBs (Tsydenova and Bengtsson, 2011) and it was detected in PCBs dust of disassembly workshops to smaller, but comparable concentrations to CRTs disassembly workshops (Song et al., 2015).As is supposedly found in various metal alloys, and circuit boards (U.S. Geological Survey, 2014) and in older type CRTs (Nguemaleu and Montheu, 2014).Steel alloy elements such as Ni (U.S. Geological Survey, 2014) and Sn contributed to Component 2, and other steel alloy elements such as Mn (Dai et al., 2015) and Cr (Kogel et al., 2006) contributed to Component 3. Ni and Cr are found in PCBs (Tsydenova and Bengtsson, 2011).
Regarding the health impacts of occupational exposure (Τable 6), non-carcinogenic risk assessment for the metals of toxicological concern shows non-acceptable risk based on the sum of HQs, for Pb, As, Cd, Ni, Sn, Cr and Mn, mainly due to the contribution of HQ of Pb, based on the quite conservative (and non-IRIS derived) RfD found in Qu et al. (2012).In agreement with our results, Pb was the main factor creating possible human health risk (out of Pb, Cu and Cd, based on dust concentrations) in a mobile e-waste recycling plant in China (Song et al., 2015).Pb again was the metal contributing to unacceptable risk (out of Cu, Pb, Cr and Cd; based on dust concentrations), mainly through ingestion, in a PCB recycling factory (Xue et al., 2012).The threat of Pb in recycling workers has also been highlighted in the study of Julander et al. (2014), in a formal recycling plant in Sweden.
Carcinogenic risk was also elevated and non-acceptable (one in a million chance of additional human cancer over a 70-year lifetime), based on inhalation exposure, due to all elements of concern (As, Ni, Cd and Cr).This is further corroborated by the probabilistic risk assessment of Li et al. (2013) in a vehicle-inspection line in China, with Ni concentrations comparable to ours (50.4 ng m -3 , 100.2 ng m -3 ; gasoline and bus line respectively), As concentrations less than half of ours (33.9 ng m -3 , 76.7 ng m -3 ; as before), Cd concentrations less than quarter of ours (2.7 ng m -3 ; as before) and Cr concentrations more than double than ours (266.2 ng m -3 , 652.5 ng m -3 ; as before).In that study, the incremental life cancer risk (based on Ni, As, Co and Cd) was within the 10 -5 rate, for half of the exposed population, signifying unacceptable adverse health effects.Unacceptable risk (in the range of 10 -4 ) was also recorded for the dismantling area of a formal e-waste plant in China, based on dust concentrations of Cd, Cr and Ni (Lau et al., 2014).Limitations in the present risk assessment study, among others, include the inherent uncertainty in risk estimation (Li et al., 2013), the variability in reference values (here selected preferentially from IRIS; Tier 1 according to USEPA, 2003) and the use of airborne particulates instead of surface and floor dust.More realistic risk assessment in the future should also include possible metal bioaccessibility in simulated fluids (Huang et al., 2018).

CONCLUSIONS
A sampling campaign in a WEEE-disassembly plant in Greece showed elevated 8-h indoor PM 10 concentrations during working hours in relation to surrounding offices or ambient air in outdoor locations.These values did not exceed the limits set by OSHA, NIOSH or Greek legislation.Elemental analysis also revealed values below the corresponding limits set by OSHA, NIOSH or Greek legislation; however, significant enrichment due to WEEE disassembly and processing was evident for the majority of the analyzed elements, especially As, Pb, Cd and Zn.Furthermore, As concentrations in the indoor samples were 140 times higher and Pb concentrations were 40 times higher than those that have been measured in the ambient air of the nearby city of Volos.Compared to other WEEE, CRT processing seemed to release different elements into the ambient air, namely, Sr, which is almost exclusively found in CRTs; Pb, which is commonly found in the back funnels of CRTs; and Cd and As, which are found in older types of CRTs.A conservative risk assessment for selected elements revealed a non-negligible lifetime risk for the workers engaging in WEEE disassembly and processing, with the non-carcinogenic risk mainly being due to the Pb and the carcinogenic risk being due to all the elements of concern (As, Ni, Cd and Cr)
and Health Administration, 2017; b National Institute for Occupational Safety and Health; c Presidential Decree 90/1999.

Table 1 .
(a) Climatological data from 25 to 31 of October 2012; (b) Climatological data from 1 to 14 of November 2012.

Table 3 .
OSHA, NIOSH 8-h TWA exposure limits and Greek Legislation 15-minutes permissible exposure levels during working hours for selected elements of toxicological concern.

Table 4 .
Enrichment factor results for certain elements in PM 10 .

Table 5 .
Pattern and Structure Matrix for PCA with Oblimin Rotation for 3 Factor Solution for elements of toxicological concern.
. More research on WEEE recycling in the EU is urgently needed.the Council of 27 January 2003 on waste electrical and electronic equipment (WEEE).Directive 2003/108/EC of the European Parliament and of the Council of 8 December 2003 amending Directive 2002/96/EC on waste electrical and electronic equipment (WEEE).Directive 2012/19/EU of the European Parliament and of the Council of 4 July 2012 on waste electrical and electronic equipment (WEEE) Emmanouil, Ch., Drositi, E., Vasilatou, V., Diapouli, E., Krikonis, K., Eleftheriadis, K. and Kungolos, A. (2017).Study on particulate matter air pollution, source origin, and human health risk based of PM 10 metal content in Volos City, Greece.Toxicol.Environ.Chem.99: 691-709.

Table 6 .
Calculated risk derived for each element of toxicological concern (Cr, Mn, Ni, Sn, Cd, Pb and As).