Environ Sci Pollut Res DOI 10.1007/s11356-015-4459-x
RESEARCH ARTICLE
PAHs in leachates from thermal power plant wastes and ash-based construction materials Natalya Irha 1 & Janek Reinik 1 & Jekaterina Jefimova 1,3 & Arina Koroljova 2,5 & Lembi-Merike Raado 4 & Tiina Hain 4 & Mai Uibu 2 & Rein Kuusik 2
Received: 30 January 2015 / Accepted: 27 March 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract The focus of the current study is to characterise the leaching behaviour of polycyclic aromatic hydrocarbons (PAHs) from oil shale ashes (OSAs) of pulverised firing (PF) and circulating fluidised-bed (CFB) boilers from Estonian Thermal Power Plant (Estonia) as well as from mortars and concrete based on OSAs. The target substances were 16 PAHs from the EPA priority pollutant list. OSA samples and OSA-based mortars were tested for leaching, according to European standard EN 12457-2 (2002). European standard CEN/TC 15862(2012) for monolithic matter was used for OSA-based concrete. Water extracts were analysed by GC– MS for the concentration of PAHs. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene were detected. Still, the release of PAHs was below the threshold limit value for inert waste. The amount of the finest fraction (particle size PF/1A EF1-3 ash>CFB/8A EF1 ash>PF/1A EF1 ash>PF/1A CA ash. Analysis of the distribution of individual PAHs revealed that leachates from ash
Average pH, EC (μS/cm) and concentration of individual PAHs (μg/L) in leachates from OSA samples (the value of the SD in parentheses)
pH EC Naphthalene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Sum of PAHs nd not detected
PF/1A EF1
PF/1A EF1-3
PF/1A CA
CFB/8A EF1
CFB/8Amix
13.10 (0.02) 13540 (27) 0.014 (0.003) 0.004 (0.008) 0.002 (0.0004) 0.010 (0.002) nd 0.004 (0.001) 0.014 (0.003) 0.048
13.10 (0.02) 14440 (29) 0.020 (0.004) 0.005 (0.001) 0.001 (0.0002) 0.014 (0.003) nd 0.004 (0.001) 0.011 (0.002) 0.055
13.0 (0.03) 11180 (22) 0.002 (0.004) 0.001 (0.002) nd 0.002 (0.004) 0.004 (0.008) 0.003 (0.001) 0.013 (0.002) 0.025
13.10 (0.03) 11520 (23) 0.002 (0.006) nd 0.001 (0.0002) 0.011 (0.002) 0.014 (0.003) 0.007 (0.001) 0.016 (0.003) 0.051
13.30 (0.03) 10880 (22) 0.004 (0.008) nd 0.001 (0.0002) 0.009 (0.002) 0.028 (0.005) 0.004 (0.008) 0.013 (0.002) 0.059
Environ Sci Pollut Res
a
b
Fig. 2 a Release (C, μg/kg) and b distribution of individual PAHs (% of sum of 16 PAHs) in leachates from OSA samples. The value of the SD was approximately 20 %
samples of electrostatic precipitators were characterised by a high percentage (>20 % of sum PAHs) of phenanthrene and pyrene. Nevertheless, the composition of leached PAHs from PF ash samples included significant amounts of naphthalene, whereas in the case of CFB ash samples, the composition comprised of 27–48 % anthracene. In the case of cyclone ash, pyrene contributed 52 % to the sum of PAHs in the leachate. The results of the experiment indicate that PAHs with low solubility including mutagenic and highly carcinogenic benzo[a]pyrene are not extracted by water because they are more hydrophobic (Table 3). The concentration of these PAHs was lower than the detection limit of the analytical methods applied.
The particle-size distribution, grain shape and surface characteristics of OSA samples as well as the content of amorphous phase were the main factors that could affect the accessibility of PAHs to leaching. The ash fractions used in the study had similar physical characteristics and chemical compositions to those employed in previous works (Irha et al. 2014; Kuusik et al. 2012; Raado et al. 2014a; Raado et al. 2014b). The corresponding PF and CFB ash types differed in grain shape, surface characteristics and particle-size distribution (Table 5). The chemical composition of OSA mainly includes CaO, SiO 2 and Al 2 O 3 (Table 6). Fresh OSA is rich in free lime, anhydrite, secondary Ca(Mg)–silicate minerals and, especially in PF ashes, an amorphous Al–Si glass phase. The content of the amorphous Al–Si glass phase in PF ash fractions varies significantly with the position in the ash removal system (Table 7) (Mõtlep et al. 2010). In the case of CFB ash fractions, the content of the amorphous phase was found at about 10–15 %, showing no significant variation between ash fractions (Kuusik et al. 2012; Pihu et al. 2012). However, the results and previously obtained data (Kuusik et al. 2012; Mõtlep et al. 2010; Pihu et al. 2012) revealed that the most important factors in PF ashes are Al–Si glass-phase content, the amount in the finest fraction (particles size
RESEARCH ARTICLE
PAHs in leachates from thermal power plant wastes and ash-based construction materials Natalya Irha 1 & Janek Reinik 1 & Jekaterina Jefimova 1,3 & Arina Koroljova 2,5 & Lembi-Merike Raado 4 & Tiina Hain 4 & Mai Uibu 2 & Rein Kuusik 2
Received: 30 January 2015 / Accepted: 27 March 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract The focus of the current study is to characterise the leaching behaviour of polycyclic aromatic hydrocarbons (PAHs) from oil shale ashes (OSAs) of pulverised firing (PF) and circulating fluidised-bed (CFB) boilers from Estonian Thermal Power Plant (Estonia) as well as from mortars and concrete based on OSAs. The target substances were 16 PAHs from the EPA priority pollutant list. OSA samples and OSA-based mortars were tested for leaching, according to European standard EN 12457-2 (2002). European standard CEN/TC 15862(2012) for monolithic matter was used for OSA-based concrete. Water extracts were analysed by GC– MS for the concentration of PAHs. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene were detected. Still, the release of PAHs was below the threshold limit value for inert waste. The amount of the finest fraction (particle size PF/1A EF1-3 ash>CFB/8A EF1 ash>PF/1A EF1 ash>PF/1A CA ash. Analysis of the distribution of individual PAHs revealed that leachates from ash
Average pH, EC (μS/cm) and concentration of individual PAHs (μg/L) in leachates from OSA samples (the value of the SD in parentheses)
pH EC Naphthalene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Sum of PAHs nd not detected
PF/1A EF1
PF/1A EF1-3
PF/1A CA
CFB/8A EF1
CFB/8Amix
13.10 (0.02) 13540 (27) 0.014 (0.003) 0.004 (0.008) 0.002 (0.0004) 0.010 (0.002) nd 0.004 (0.001) 0.014 (0.003) 0.048
13.10 (0.02) 14440 (29) 0.020 (0.004) 0.005 (0.001) 0.001 (0.0002) 0.014 (0.003) nd 0.004 (0.001) 0.011 (0.002) 0.055
13.0 (0.03) 11180 (22) 0.002 (0.004) 0.001 (0.002) nd 0.002 (0.004) 0.004 (0.008) 0.003 (0.001) 0.013 (0.002) 0.025
13.10 (0.03) 11520 (23) 0.002 (0.006) nd 0.001 (0.0002) 0.011 (0.002) 0.014 (0.003) 0.007 (0.001) 0.016 (0.003) 0.051
13.30 (0.03) 10880 (22) 0.004 (0.008) nd 0.001 (0.0002) 0.009 (0.002) 0.028 (0.005) 0.004 (0.008) 0.013 (0.002) 0.059
Environ Sci Pollut Res
a
b
Fig. 2 a Release (C, μg/kg) and b distribution of individual PAHs (% of sum of 16 PAHs) in leachates from OSA samples. The value of the SD was approximately 20 %
samples of electrostatic precipitators were characterised by a high percentage (>20 % of sum PAHs) of phenanthrene and pyrene. Nevertheless, the composition of leached PAHs from PF ash samples included significant amounts of naphthalene, whereas in the case of CFB ash samples, the composition comprised of 27–48 % anthracene. In the case of cyclone ash, pyrene contributed 52 % to the sum of PAHs in the leachate. The results of the experiment indicate that PAHs with low solubility including mutagenic and highly carcinogenic benzo[a]pyrene are not extracted by water because they are more hydrophobic (Table 3). The concentration of these PAHs was lower than the detection limit of the analytical methods applied.
The particle-size distribution, grain shape and surface characteristics of OSA samples as well as the content of amorphous phase were the main factors that could affect the accessibility of PAHs to leaching. The ash fractions used in the study had similar physical characteristics and chemical compositions to those employed in previous works (Irha et al. 2014; Kuusik et al. 2012; Raado et al. 2014a; Raado et al. 2014b). The corresponding PF and CFB ash types differed in grain shape, surface characteristics and particle-size distribution (Table 5). The chemical composition of OSA mainly includes CaO, SiO 2 and Al 2 O 3 (Table 6). Fresh OSA is rich in free lime, anhydrite, secondary Ca(Mg)–silicate minerals and, especially in PF ashes, an amorphous Al–Si glass phase. The content of the amorphous Al–Si glass phase in PF ash fractions varies significantly with the position in the ash removal system (Table 7) (Mõtlep et al. 2010). In the case of CFB ash fractions, the content of the amorphous phase was found at about 10–15 %, showing no significant variation between ash fractions (Kuusik et al. 2012; Pihu et al. 2012). However, the results and previously obtained data (Kuusik et al. 2012; Mõtlep et al. 2010; Pihu et al. 2012) revealed that the most important factors in PF ashes are Al–Si glass-phase content, the amount in the finest fraction (particles size
