Arch Environ Contam Toxicol DOI 10.1007/s00244-015-0136-9
Occurrence and Source Appraisal of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Waters of the Almendares River, Cuba Jorge Luis Santana • Carlos German Massone • Michel Valde´s • Rene Vazquez • La´zaro Antonio Lima Susana Olivares-Rieumont
•
Received: 18 March 2014 / Accepted: 1 February 2015 Ó Springer Science+Business Media New York 2015
Abstract In this work, 14 polycyclic aromatic hydrocarbons (PAHs) included in the United States Environmental Protection Agency pollutant priority list were analyzed in the surface water of the upper urbanized part of Almendares River, the most important water course in Havana, Cuba. Surface water from five sampling sites was collected at the end of dry season and analyzed by highperformance liquid chromatography-fluorescence detection method after solid phase extraction procedure. Total PAHs concentrations varied from 836 to 15 811 ng L-1 with a geometric mean value of 2512 ng L-1. PAH typology was dominated by low molecular-weight PAHs (2- to 3-ring components). Pollutant source appraisal was determined by diagnostic ratios method in five sampling sites. Factor analysis of normalized samples was used to concentration identified two factors as the main significant pollutant sources and to cluster similar sampling sites corresponding to petrogenic and combustion inputs, respectively. Ecological risks were considered. For animal aquatic life, acute toxicity values exceed the permissible values in the morepolluted sampling sites.
Polycyclic aromatic hydrocarbons (PAHs) represent a widespread class of environmental chemical pollutants (Shi et al. 2005; Zhang et al. 2012a, b). Owing to their J. L. Santana (&) M. Valde´s R. Vazquez L. A. Lima S. Olivares-Rieumont Facultad de Medio Ambiente, Instituto Superior de Tecnologia y Ciencias Aplicadas, La Habana, Cuba e-mail: [email protected] C. G. Massone Chemistry Department, Pontificia Universidad Cato´lica, Rio de Janeiro, Brasil
persistency, toxicity, and high mutagenic and carcinogenic activity, PAHs have attracted the attention of scientists from many countries (Christensen and Bzdusek 2005; Meyer et al. 2011; Wang et al. 2013; Man et al. 2013; Ballesteros-Go´mez et al. 2008). PAHs are common pollutants in air, water, sediments, and biota contributing to serious environmental and health problems including cancer. The majority of scientific literature concerning PAHs are related to the atmospheric (Khairy and Rainer 2013) or sediment (Tolosa et al. 2009; Massone et al. 2013) matrices. Studies have also documented PAHs in water mainly to record recent inputs of contamination (Zhang et al. 2012a, b). PAHs are known to enter aquatic environments mainly through industrial discharges, petroleum spills, combustion of fossil fuel, urban runoff, and atmospheric deposition among others (Qiu et al. 2009; Li et al. 2006; Pereira et al. 2006). These compounds may exist in a free dissolved phase bounded to dissolved organic matter, adsorbed to suspended particulate matter and associated with surface sediments (Shi et al. 2005). Due to their high hydrophobicity, PAHs in water tend to associate with particulate matter and accumulate in bottom sediment (Shi et al. 2005). Sediments can act as a sink that may operate as a further source of pollution; hence, pollutants may release pollutants back into the water column (Sofowote et al. 2008). The distribution of PAHs among these phases is mainly controlled by the physicochemical properties of the individual compounds in specific systems (Zhou and Maskaoui 2003) and may be modified in the presence of several additives such as surfactants. Natural processes, such as diffusion, storms, tidal changes, transport properties, and even anthropogenic action, can cause resuspension, mobilization, or enhancement of the solubility of
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PAHs in aquatic system as a part of local hydrodynamic phenomena (Geffard et al. 2003). The Almendares Rivers basin is one of the most important hydrological basins in Cuba (Olivares-Rieumont et al. 2005). The river’s waters are used by approximately 500,000 inhabitants for social, recreational, agricultural, or industrial purposes in which recreational uses and land irrigation are significant activities. Inadequate water management, urban runoff, and uncontrolled contaminant inputs were identified as causes of water-quality deterioration (Graham et al. 2011; Alcolado-Prieto et al. 2012). Cooperative fisheries (350 tons year-1) normally were performed in the lowest reach of the river. Recently, evidence of antibiotic gene resistance was found in Almendares River (Graham et al. 2011; Knapp et al. 2012). The population discharges contaminants to the river through domestic, municipal, and industrial wastewaters. Contaminant loadings increase through runoff and atmosphere depositions in the city from one of the oldest and contaminant vehicle fleets in the world. Knowledge about PAH determination in Almendares River water is of concern because the river is used by residents for important social activities. Concerning PAHs apportion pollution sources, several receptor models have been developed in past decades (Shi et al. 2011; Zhang et al. 2012a, b; Ma et al. 2010; Yang et al. 2013). Among them, the diagnostic ratios method has been frequently used. The diagnostic ratios method (Yunker et al. 2002; Mares and Pereira 2009; Szabo et al. 2012; Tobiszewski and Namiesnik 2012) is based on conservativeness of the chemical balance proportion of isomeric mass ratios of pollutants in sources and in the environmental samples; it is able to supply useful information and constitutes the most frequent method for source appraisal. The objective of the present study was to document the composition and distribution of PAHs, especially those listed by the USEPA with human carcinogenic or mutagenic effects, in the Almendares River, Havana, Cuba. We compare results from the present study to PAH levels reported in other rivers.
Materials and Methods Site Description Almendares River is the most important river of Havana, the capital city of Cuba. The river discharges an average of 15,576,000 m3 year-1 (0.53 m3 s-1) (Domı´nguez et al. 2004) of water from a 40,202 km2 drainage basin. Almendares River and its small tributaries run almost 6 km through the upper urban section of Havana. Through this route it receives numerous uncontrolled inputs from sewer
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and different factories (foods, pharmaceutical, paint, and electronics). The largest provincial Calle 100 landfill for solid-waste discharge lixiviates into the river. Pollutants as PAHs can reach the river through city runoff or atmospheric fall-out. Although the river has little waterfalls along its course, which may act to improve water quality, pollution levels are considerable. High values of chemical oxygen demand (2034 tons year-1) were recently determined (Alcolado-Prieto et al. 2012). Aquatic life in the river is scarce in general and practically absent in some intermediate places of the urban reach of the river. The average depth of the river is 0.62 m in dry season, and the width in all studied locations is approximately 7 m (Dominguez et al. 2004). The climate is subtropical with a dry winter and rainy summer season. The zone under study is located in approximately four densely populated municipalities. In Fig. 1, the localization of sampling sites is shown. Sample Collection River water samples were collected and stored as recommended by the American Public Health Association (2005). Sampling campaign was performed in March 2013 (dry season) to determine the worst-case scenario for organic contamination in river waters. Approximately triplicate 1000 mL samples of surface waters were collected in each of five sampling stations (Table 1) in previously cleaned amber flasks (1 L) and baked overnight at 400 °C. Before analysis, samples were filtrated using a 0.45 lm glass fiber filters. The sites of water sampling are listed in Table 1. Chemical and Reagents A standard solution, traceable to NIST containing 16 priority USEPA PAHs. Solid PAHs were received from Sigma-Aldrich. High-performance liquid chromatography (HPLC)-grade methanol, n-hexane, dichloromethane, and acetonitrile were purchased from Merck. Milli-Q-quality water was used in the analytical procedure. Analyticalgrade silica gel and alumina (100–200 mesh) were washed twice with dichloromethane and then baked at 250 °C for 12 h. Sodium sulfate was baked at 450 °C and then stored in sealed desiccators. Analytical Methods PAHs in water phase were concentrated by solid phase extraction in 1 g C18 cartridges from LiChrosorb, Merck. Before extraction, the cartridges were conditioned with 5 mL of methanol under vacuum conditions followed by 5 mL of ultra-pure water. After spiking with surrogate
Arch Environ Contam Toxicol
Fig. 1 Sampling stations localization in Almendares River for water analysis
Table 1 Locations of the sampling stations along the Almendares River No
Sampling sites
Position
Description
1
El bosque bridge
Latitude 23°, 060 , 30.100 ; longitude 82°, 240 , 26.400
Site is situated in a recreational parkland with vegetation along the sides
2
Puentes grandes
Latitude 23°, 050 , 30.100 ; longitude 82°, 240 , 55.300
Site is adjacent to a high-traffic road; road runoff discharges directly to river waters
3
Husillo bridge
Latitude 23°, 050 , 06.900 ; longitude 82°, 240 , 00.700
Site is covered by vegetation; detergent inputs cause a considerable stable foam formation on surface waters
4
Marinero
Latitude 23°, 030 , 58.000 ; longitude 82°, 240 , 14.800
Station is situated near the outfall of Calle 100 landfill lixiviates channel; under direct influence of aerosols and fumes from spontaneous fires from landfill
5
Calle Sur
Latitude 23°, 030 , 30.400 ; longitude 82°, 240 , 02.400
Site is situated in parallel with Calle 100 landfill near small farmer ranch; visible presence of oil spills in surface waters
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standards, a total volume of river water samples (1 L) was passed through the cartridges at flow rate of 5 mL min-1. The organic pollutants retained on the C18 cartridges were eluted with 6 mL of n-hexane. The sample extract was separated over 5 % alumina in silica gel mixed sorbent column, 5 % w/w H2O. The first fraction was eluted from the column with n-hexane (10 mL), and the second fraction was eluted with a mixture of 2:7 v/v n-hexane and dichloromethane (20 mL). The second fraction was concentrated in a micro Kuderna–Danish device to 1 mL. Qualitative and quantitative determination of PAHs was performed by HPLC with fluorescence detection (FLD). A Shimadzu 20 A T Series chromatograph with an automatic injector, a column oven, a quaternary flow pump, and a fluorescence detector was used. A C18 Phenomenex HPLC column (250 9 4.6 mm, id 5 lm) was used with a binary polarity elution gradient of 1.2 mL/min water (A) and acetonitrile (B), in a temperate column (40 °C). The gradient was as follows: 40 % of B held for 10 min, increased linearly up to 100 % after 35 min, held for 10 min, and decreased to 40 % to allow for equilibration before the next injection. Acenaphthylene was not evaluated in the samples because of its low fluorescence intensity. The recommended maximum excitation and emission wavelengths were employed for PAH detection (Titato and Lanc¸as 2006). Laboratory solutions software was used for data analysis. Calibration curves were built from 0.1 and 200 lgL-1 of standard solution containing the studied PAHs. Determination of detection limits (DL) and quantification limits (QL) were established from calibration curves. DL and QL were established from the analytical background response (y value, intercept value of regression curve) plus three times the SD of this response value (Miller and Miller 2002). Quality-assurance procedures included analysis of duplicates, blanks, blanks spikes, and matrix duplicates spikes. Replicate samples were analyzed for all collected samples from each station. Reagent blank and recovery procedures were analyzed simultaneously for every five samples. The accuracy of the analytical procedure was examined by recovering the PAHs that had been previously added in different amounts to river samples (Titato and Lanc¸as 2006). The final concentrations were corrected by surrogate recovery data. Analysis of Data The results of determinations (Table 2) were expressed as a means values in samples from each site with associated expanded uncertainty and calculated using K = 2 as a covertures factor according to EuroChem Guide (2002). Pollutant source appraisal was performed by diagnostic
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ratios method (Yunker et al. 2002). Principal component analysis (PCA) factor plotting was used to group similar sample composition sets. PCA of randomized concentration data were performed to identify the latent factors of results variability (factor loadings). Ecological Risk Determination Individual PAH potency equivalency factors (PEFs) relative to benzo(a)pyrene (BaP) were adopted for the assessment of seven carcinogenic PAHs (PAHscarcinogenic), i.e., benzo(a)anthracene (BaA), chrysene (Chr), benzo(b)fluoranthene (BbF), benzo(b)fluoranthene (BkF), BaP, indeno(1,2,3-cd) pyrene (InP), and dibenzo (a,h) anthracene (DBA). These factors were taken from the recommendations of Canadian Council of Ministers of the Environment (CCME) Declaration document (CCME 2010) and from Nisbet and LaGoy (1992) to estimate multicomponent PAH exposure in ecosystems. Individual carcinogenic PAH concentrations were multiplied by their toxic equivalent concentration factor and the result were summed up leading to total toxic equivalent concentrations (TTEC). For the ecological assessment, data were compared with reported Canadian Water Quality Guidelines values for BaP according to aquatic life protection criteria. In addition, chronic and acute toxicity exposition levels for aquatic life protection in the river were estimated according to the United States Environmental Protection Agency (2004) approach model of Equilibrium Sediment Benchmark calculation (USEPA PAH ESB).
Results and Discussion Calibration curves used for analysis presented correlation coefficients (r2 C 0.999) showing a good relationship between concentrations and fluorescence intensity in the studied range. Metrological limits were sufficiently low (0.25–8.1 ng L-1) to determine 14 PAH concentrations in all sampling stations. Acenaphthylene was excluded due to its low intensity florescence emission, and naphthalene was excluded due to low recovery values. The measured concentration of 14 individual PAHs and total PAH concentrations in water in the all sampling sites were tested for their distribution patterns using Kolmogorov–Smirnov test. The result shown the data were distributed according normal function, p B 0.05. PAH Concentrations in Almendares River Water PAH concentrations determined in the surface waters of Almendares River are listed in Table 2. The calculation of uncertainty of determinations was performed according to
Arch Environ Contam Toxicol Table 2 Determination of PAHs in Almendares River waters (ng/L) with associated uncertainties (K = 2) PAH
S1
S2
S3
S4
S5
Acenaphthene
190 ± 36
208 ± -40
449 ± -66
115 ± -26
1407 ± -102
Fluorene
185 ± -43
216 ± -37
563 ± -58
257 ± -65
2537 ± -226
Phenanthrene
242 ± -5
287 ± -34
1268 ± -137
950 ± -72
7337 ± -317
Anthracene
40 ± -8
46 ± -10
73 ± -14
180 ± -38
594 ± -92
Fluoranthene
43 ± -13
60 ± -15
249 ± -52
210 ± -47
1191 ± -118
Pyrene
45 ± -8
57 ± -12
487 ± -57
126 ± -27
1700 ± -189
Benzo(a)anthracene
17 ± -4
28 ± -5
53 ± -12
83 ± -15
104 ± -12
Chrysene
23 ± - 4
29 ± -4
178 ± -32
130 ± -19
681 ± -94
Benzo(b)fluoranthene
6 ± -2
12 ± -3
45 ± -8
37 ± -5
15 ± -5
Benzo(k)fluoranthene
8 ± -3
10 ± -2
37 ± -4
30 ± -4
26 ± -8
Benzo(a)pyrene Indeno(1,2,3-cd) pyrene
14 ± -5 4 ± -1
19 ± -5 6 ± -2
43 ± -5 22 ± -3
26 ± -4 7 ± -2
79 ± -18 18 ± -3
Dibenzo(a,h) anthracene
5 ± -2
6 ± -2
56 ± -4
15 ± -5
34 ± -6
Benzo(g,h,i)perylene
7 ± -4
5 ± -3
58 ± -6
19 ± -8
67 ± -10
RPAHs14
836 ± -178
1001 ± -137
3530 ± -458
2140 ± -337
15811 ± -1200
2 rings (%)
22
21
13
4
9
3 rings (%)
61
61
61
70
61
4 rings (%)
11
13
22
20
16
5 to 6 rings (%)
6
5
4
16
14
77 ± -1
80 ± -3
434 ± -68
339 ± -62
957 ± -146
RPAHscarcinogenic
Values represent means of at least three determinations in each site Table 3 Geometric mean values of total PAHs concentrations (ng L-1) in rivers worldwide Sampling sites
Mean
References
Mississippi River, USA
115
Zhang et al. (2007)
Seine River, France
20
Fernandes et al. (1997)
Slave River, Canada
29
McCarthy et al. (1997)
St. Lawrence River, Canada
326
Pham et al. (1999)
Yangtze River, China
491
Guo and co-workers (2012b)
Huaihe River, China
4385
Guo and co-workers (2012b)
Liaohe River, China Tianjins River
4021 35,000
Guo and co-workers (2012b) Cao et al. (2005)
Almendares River, Cuba
2784
This study
EuraChem Guide (2002). In Table 3, total PAH concentrations (geometric means) of some representative rivers in the world are listed. Total PAHs concentrations (RPAHs14) in dissolved phase ranged from 836 to 15,811 ng L-1. The average confidence interval for measured value (RPAHs14) in the five studied sampling stations achieved 15 % of central values. The geometric mean of RPAHs14 values in the present investigation was 2512 ng L-1 indicating the high pollutant level of river waters. The highest concentration corresponds to site 5. Relatively high content of 2-ring PAHs, which are well known for their lower persistence in aquatic ecosystems due to photolysis, degradation, and evaporation, among
other processes, possibly indicates a process that involves systematic and/or recent inputs of contaminants from petrogenic sources. PAH concentrations between the upstream sites (e.g., site 5) and the downstream sites are significantly different. Even when the pollutant concentration level is descending from upstream to downstream sites in a river, the hypothesis of dilution transport concentration of pollutant will be inadequate to describe the contaminant behavior in the river waters. In fact, among the low river flow of Almendares River, which allows PAHs to move from river waters to sediment or atmosphere phases, the presence of some small waterfalls, which improve the water quality in the Almendares River, contribute significant contaminant inputs of tributaries containing industrial discharges without treatment and high suspended particulate matter influents (e.g., site 4) affect the composition and total concentration of PAHs in Almendares River waters. These facts render difficult the analysis of probable dilution transportation model of PAH contamination from site 5. In average, [95 % of total PAH concentrations in a river is represented by 2- to 4- ring PAHs, which is consistent with their higher solubility in water. Specifically 3-ring PAHs were predominant (66 %). Phenanthrene was the predominant pollutant in the samples. As listed in Table 3, the Almendares River water PAH content is high. The PAH concentration levels found were
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higher than levels reported for some larger, navigable rivers such as the Mississippi, Seine, or Saint Lawrence rivers, belonging to developed countries with considerable industrial and energy production and fossil fuel consumption. Northern China rivers, immersed in highly polluted industrial environments, have higher pollutant concentrations than the Almendares River. A decreased amount of Cuban industrial production compared with those countries allow consideration that petrogenic inputs, such as industrial residual waters or oil spillage, are the main cause of the high pollution level present in more contaminated waters. Identification of PAH Sources The relative contributions of the major origins of PAH pollution was additionally estimated using factor analysis (PCA). PCA was also performed using a randomized data of PAH concentrations to determine significant factors. The initially obtained three factors with eigenvalues [1 were subjected to parallel analysis procedure using software ViSta v.7.9.2.5 (Ledesma and Valero 2007) to retain only the significant eigenvalues and their corresponding loading factors. Only two factors were significant in the parallel analysis. The obtained loading factors (Fig. 2) for each variable were used to characterize a possible pollutant source. Obtained factor scores show the variable’s behavior in each sampling station. Values for factor loadings and graphic representation of contribution of factors are shown (Fig. 2).
Fig. 2 Factor loadings and scores after PCA analysis
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Loadings for factor 1 characterize a petrogenic input. All of the sites, with exception of sampling site 4 (combustion source), were predominantly affected by a petrogenic source. Sites 3 and 5 were the best represented by this dominant petrogenic factor according to factor scores values. Stations 1 and 2 have a mixed influence from petrogenic and combustion sources. Factor 2 represents a combustion factor. The best represented stations were the stations 1 and 2. Factor-plotting analysis (Fig. 3) allows clustering of similar sites. In addition, it is possible to differentiate the petrogenic inputs in the sites. The diagnostic ratios method is used to distinguish the sources whether petrogenic and pyrogenic (combustion). PAHs in different environment media depend on thermodynamic properties similarities of isomers, such as partitioning and kinetic mass transfer coefficients and stability against photolysis (Yunker et al. 2002). This method is sustained on the assumption of conservativeness of different species’ isomeric ratios proportions in each evaluated source and its nonmodification from source and measurement points. Although it is recognized that before that source appraisal can be based on this, is not a robust enough asumption (Wagener et al. 2012); however, it is very useful method of probable source identification of PAHs. If the ratio of Ant/Ant ? Phe is [0.1, the source is usually assumed to be pyrogenic, whereas a ratio \0.1 suggests petroleum sources. However, for some specific
Arch Environ Contam Toxicol Fig. 3 Factors plot for sampling stations. Case F1 versus F2
fuels (diesel, used engine oil) the indicator must be[0.1. In our study, the values of the Ant/Ant ? Phe ratio were 0.2, 0.12, and 0.13 for sampling sites 1, 2, and 4, respectively, which allow their classified as being mainly affected by pyrogenic sources. Petroleum source was proposed for sites 3 and 5, where the indicator values were 0.05 and 0.07, respectively. Possible contributing sources of PAHs in the former sites (sites 1, 2, and 4) are the combustion of fossil fuels (industries and cars) and dry and wet deposition (atmospheric and road runoff). Additionally, site 4 s influenced by fumes, aerosols, and direct atmospheric depositions of combustion products from spontaneous fires of organic materials (wood, exhausted oils, and trees foliage among other flammable residues) from Havana landfill, which is located near this site. The Flu/(Flu ? Pyr) indicator values for site 3 occupies an intermediate position (0.35) between petroleum sources of PAHs and those corresponding to combustion products. It is probable that mixed sources can be responsible for PAHs presence in this sampling station. Attention must be paid to the relatively high contents of heavy PAHs compared with other sites as listed in Table 3. For site 5, a ratio of Flu/(Flu ? Pyr) \ 0.5 indicates a petroleum sources. This fact corresponds with the source identification described in previous text. The disposal of exhausted oils and petroleum derivatives is probably the main cause of higher PAH concentrations in the studied sites. According to Yunker et al. (2002), a ratio of BaA/ (Chr ? BaA) \ 0.2 indicates petroleum sources. Values between 0.2 and 0.35 indicate possible mixed sources
(petroleum and combustion contamination), and values [ 0.35 values indicate combustion sources. Similar behavior it is observed for ratio of indeno(1,2,3-cd) pyrene/ [indeno(1,2,3-cd) pyrene ? benzo(g,h,i)perylene] according to Yunker et al. (2002), Li et al. (2006), and Zhang et al. (2007). Taking into account the limitations of the diagnostic ratios methods already described, PCA was applied to obtain additional information from factor analysis. Two factors showed significant eigenvalues[1 according to the results of parallel analysis (Fig. 2). Composition of factor 1 must be associated with petrogenic input and explains 51 % of the total variance (Fig. 2). The sites 3 and 5 are the best represented by this factor, but the contribution of this factor is not negligible in sites 1 and 2. This fact was expected and is consistent with the visual diagnostic record of sampling procedure listed in Table 1. There is a complete correspondence with the results of the diagnostic ratio method, which identified a dominant petrogenic pollution source in sites 3 and 5. For sampling site 2, intermediate results between petrogenic and combustion sources are shown due to fluctuating results from the different observations (n = 4, 5, and 6 observations in the same sampling site). This result is consistent with previous pollutant source identification by the diagnostic ratio method (Table 4). Explanation of this experimental fact must be founded in water sampling in a river with low, nonturbulent water flow that receives inputs from different sources without adequate mixing process. Factor 2 has positive loadings for light and heavy PAHs with increased thermodynamic stability and must be associated with combustion pollution sources. This factor
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Arch Environ Contam Toxicol Table 4 Site-specific results for diagnostic ratios source appraisal method Station
Ant/(Ant ? Phe)
BaA/(Chr ? BaA)
Flu(/Flu ? Pyr)
InP/(InP ? BgP)
Criterion
1
0.14
0.48
0.43
0.4
C
2
0.86
0.5
0.49
0.5
C
3
0.05
0.34
0.23
0.16
P
4
0.16
0.62
0.39
0.26
C
5
0.07
0.4
0.13
0.21
P
Sources*
[0.1 combustion (C)
\0.2 petroleum (P)
\0.4 petroleum (P)
\0.2 petroleum (P)
\0.1
\0.2 \ x \ 0.35 mixed (M)
\0.4 \ x \ 0.5 combustion
\0.2 \ x \ 0.5 combustion
Petroleum P
[0.35 combustion
[0.5 coal, wood comb
[0.5 coal, wood comb
* Yunker et al. (2002), Li et al. (2006), and Zhang et al. (2007)
explains 32 % of the total variance. The sites with better representation by this factor are sites 1 and 2. PCA analysis (factor plotting) allows clustering of the sites with the same composition pattern under influence of different sources considering the pollution contributions from different sources in a complex river system (Fig. 3). Analysis of factors plots showed four groups of sampling stations differentiated by the results of factor 1 and 2 ratios. Sampling stations 3 and 5 were predominantly affected by petrogenic input. Stations 1 and 2 have similar positions, indicating a similar composition for both sites, largely influenced by petrogenic and combustion processes. It is possible to differentiate in these sites (sites 1 and 2) recent petrogenic inputs due to the presence of lighter weight PAHs from the oldest one, which is present in stations 3 and 5. Sampling station 4 presents the most dispersive cluster possibly due to the influence of high particulate matter content in water samples due to landfill proximity and its influence in the determination of individual components. The same cause is responsible for the ambiguity in source identification using PCA at the same station due possibly to pattern typology changes.
Fig. 4 Total toxic equivalent concentrations (TTEC) in the five sampling stations for water quality monitoring in Almendares River. The results are expressed in ng BaP eq. L-1. Critical reference value: 15 ng L-1 (CCME, 2010)
Ecological Risk Determination The values of total toxic equivalent concentration for the studied sites are shown in Fig. 4. The calculated results for model of the equilibrium sediment benchmark calculation (USEPA PAH ESB) procedure for acute and chronic exposition of aquatic life in the Almendares River are shown in the Fig. 5. The highest PAH concentrations were found in site 5, which is in correspondence with visibly the more deteriorated ecosystem due to oil spillage inputs from industrial sources. The lowest PAH concentrations were found in site 1 corresponding to recreational activities. Regarding risk assessment, in all cases the achieved values were [0.015 lg L-1, which is the recommended
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Fig. 5 EPA PAHs ESB results for acute (black color columns) and chronic (grey color columns) toxicity values for aquatic life in the Almendares River. Critical reference value: 1 lgL-1
value for BaP concentration in Canadian Water Quality Guidelines, or 0.0038 and 0.018 lg L-1 for chronic and acute human safety exposition in freshwaters systems, respectively, according to USEPA. Acute toxicity values
Arch Environ Contam Toxicol
(black column values in Fig. 5) exceed the permissible value of 1 in sites 3, 4, and 5. In site 5, the proposed limit value exceeds [10 times that of the analyzed waters. Concerning chronic exposure, only station 5 is affected according to the determined pollutant concentration.
Conclusion The present study provided important data on the occurrence, distribution, and source apportionment of PAHs in the surface waters of Almendares River. To minimize the uncertainties in pollution source identification and to obtain a better description of all possible inputs influences in the river, diagnostic ratio analysis and PCA factor analysis were applied to estimate source contributions for water PAH contamination. The derived individual diagnostic PAH ratios suggested that important contribution for this pollution has come from petrogenic activity. Consistent with the aforementioned method, similar conclusions were achieved applying PCA analysis for randomized samples. The identification of major emission sources is an essential step in seeking to control, manage, and ameliorate environmental pollution. Regarding ecological risk assessment, it was undertaken to study the potential ecological risk induced by seven carcinogenic PAHs in Almendares River surface water. The results of this study indicate that despite probable uncertainties common in toxicity risk assessment, these results could be useful for the identification and management of ecological risk posed by PAHs in surface water, and mitigation efforts should be considered in the near future. Acknowledgments The authors are grateful to Coordinac¸ao de Aperfeic¸oamento de Pessoal de Nı´vel Superior for supporting determinations and discussion of obtained results through CAPES-MES project 149/12.
References Alcolado-Prieto P, Caballero Arago´n H, Alcolado P, Lopeztegui Castillo A (2012) Reclutamiento de corales pe´treos en arrecifes coralinos a diferentes distancias de fuentes de contaminacio´n en La Habana Cuba. Rev Biol Trop 60(3):981–994 American Public Health Association (2005) Standard methods for the examination of water and wastewaters. APHA, Washington, DC Ballesteros-Go´mez A, Rubio S, Pe´rez-Bendito D (2008) Determination of priority carcinogenic polycyclic aromatic hydrocarbons in wastewater and surface water by coacervative extraction and liquid chromatography–fluorimetry. J Chromatogr A 1203(2): 168–176 Canadian Council of Ministers of the Environment (2010) Canadian soil quality guidelines: Carcinogenic and other polycyclic aromatic hydrocarbons (PAHs): Environmental and human health effects. Scientific supporting document. PN 1401. CCME
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risk assessment. Final. USEPA/540/R-99/005, OSWER 9285.702EP Wagener ALR, Meniconi MFG, Hamacher C, Farias CO, Silva GC, Gabardo IT et al (2012) Hydrocarbons in sediments of a chronically contaminated bay: the challenge of source assignment. Mar Pollut Bull 64(2):284–294 Wang XT, Miao Y, Zhang Y, Li YC, Wu MH, Yu G (2013) Polycyclic aromatic hydrocarbons (PAHs) in urban soils of the megacity Shanghai: Occurrence, source apportionment and potential human health risk. Sci Total Environ 447(1):80–89 Yang D, Qi S, Zhang Y, Xing X, Liu H, Qu C et al (2013) Levels, sources and potential risks of polycyclic aromatic hydrocarbons (PAHs) in multimedia environment along the Jinjiang River mainstream to Quanzhou Bay, China. Mar Pollut Bull 76(1):298–306 Yunker MB, Macdonal RW, Vingarzan R, Mitchell RH, Goyette D, Sylvestre S (2002) PAHs in the Fraser River Basin: a critical appraisal of PAH ratios as indicators of PAH source and composition. Organic Geochem 33(4):489–515 Zhang SY, Zhang Q, Darisaw S (2007) Simultaneous quantification of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pharmaceuticals and personal care products (PPCPs) in Mississippi river water, in New Orleans, Louisiana, USA. Chemosphere 66(6):1057–1069 Zhang L, Dong L, Ren L, Shi S, Zhou L, Zhang T et al (2012a) Concentration and source identification of polycyclic aromatic hydrocarbons and phthalic acid esters in the surface water of the Yangtze River Delta, China. J Environ Sci 24(2):335–342 Zhang Y, Guo CS, Xu J, Tian YZ, Shi GL, Feng Y-C (2012b) Potential source contributions and risk assessment of PAHs in sediments from Taihu lake, China: Comparison of three receptor models. Water Res 46(9):3065–3073 Zhou JL, Maskaoui K (2003) Distribution of polycyclic aromatic hydrocarbons in water and surface sediments from Daya Bay, China. Environ Pollut 121(2):269–281
Occurrence and Source Appraisal of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Waters of the Almendares River, Cuba Jorge Luis Santana • Carlos German Massone • Michel Valde´s • Rene Vazquez • La´zaro Antonio Lima Susana Olivares-Rieumont
•
Received: 18 March 2014 / Accepted: 1 February 2015 Ó Springer Science+Business Media New York 2015
Abstract In this work, 14 polycyclic aromatic hydrocarbons (PAHs) included in the United States Environmental Protection Agency pollutant priority list were analyzed in the surface water of the upper urbanized part of Almendares River, the most important water course in Havana, Cuba. Surface water from five sampling sites was collected at the end of dry season and analyzed by highperformance liquid chromatography-fluorescence detection method after solid phase extraction procedure. Total PAHs concentrations varied from 836 to 15 811 ng L-1 with a geometric mean value of 2512 ng L-1. PAH typology was dominated by low molecular-weight PAHs (2- to 3-ring components). Pollutant source appraisal was determined by diagnostic ratios method in five sampling sites. Factor analysis of normalized samples was used to concentration identified two factors as the main significant pollutant sources and to cluster similar sampling sites corresponding to petrogenic and combustion inputs, respectively. Ecological risks were considered. For animal aquatic life, acute toxicity values exceed the permissible values in the morepolluted sampling sites.
Polycyclic aromatic hydrocarbons (PAHs) represent a widespread class of environmental chemical pollutants (Shi et al. 2005; Zhang et al. 2012a, b). Owing to their J. L. Santana (&) M. Valde´s R. Vazquez L. A. Lima S. Olivares-Rieumont Facultad de Medio Ambiente, Instituto Superior de Tecnologia y Ciencias Aplicadas, La Habana, Cuba e-mail: [email protected] C. G. Massone Chemistry Department, Pontificia Universidad Cato´lica, Rio de Janeiro, Brasil
persistency, toxicity, and high mutagenic and carcinogenic activity, PAHs have attracted the attention of scientists from many countries (Christensen and Bzdusek 2005; Meyer et al. 2011; Wang et al. 2013; Man et al. 2013; Ballesteros-Go´mez et al. 2008). PAHs are common pollutants in air, water, sediments, and biota contributing to serious environmental and health problems including cancer. The majority of scientific literature concerning PAHs are related to the atmospheric (Khairy and Rainer 2013) or sediment (Tolosa et al. 2009; Massone et al. 2013) matrices. Studies have also documented PAHs in water mainly to record recent inputs of contamination (Zhang et al. 2012a, b). PAHs are known to enter aquatic environments mainly through industrial discharges, petroleum spills, combustion of fossil fuel, urban runoff, and atmospheric deposition among others (Qiu et al. 2009; Li et al. 2006; Pereira et al. 2006). These compounds may exist in a free dissolved phase bounded to dissolved organic matter, adsorbed to suspended particulate matter and associated with surface sediments (Shi et al. 2005). Due to their high hydrophobicity, PAHs in water tend to associate with particulate matter and accumulate in bottom sediment (Shi et al. 2005). Sediments can act as a sink that may operate as a further source of pollution; hence, pollutants may release pollutants back into the water column (Sofowote et al. 2008). The distribution of PAHs among these phases is mainly controlled by the physicochemical properties of the individual compounds in specific systems (Zhou and Maskaoui 2003) and may be modified in the presence of several additives such as surfactants. Natural processes, such as diffusion, storms, tidal changes, transport properties, and even anthropogenic action, can cause resuspension, mobilization, or enhancement of the solubility of
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PAHs in aquatic system as a part of local hydrodynamic phenomena (Geffard et al. 2003). The Almendares Rivers basin is one of the most important hydrological basins in Cuba (Olivares-Rieumont et al. 2005). The river’s waters are used by approximately 500,000 inhabitants for social, recreational, agricultural, or industrial purposes in which recreational uses and land irrigation are significant activities. Inadequate water management, urban runoff, and uncontrolled contaminant inputs were identified as causes of water-quality deterioration (Graham et al. 2011; Alcolado-Prieto et al. 2012). Cooperative fisheries (350 tons year-1) normally were performed in the lowest reach of the river. Recently, evidence of antibiotic gene resistance was found in Almendares River (Graham et al. 2011; Knapp et al. 2012). The population discharges contaminants to the river through domestic, municipal, and industrial wastewaters. Contaminant loadings increase through runoff and atmosphere depositions in the city from one of the oldest and contaminant vehicle fleets in the world. Knowledge about PAH determination in Almendares River water is of concern because the river is used by residents for important social activities. Concerning PAHs apportion pollution sources, several receptor models have been developed in past decades (Shi et al. 2011; Zhang et al. 2012a, b; Ma et al. 2010; Yang et al. 2013). Among them, the diagnostic ratios method has been frequently used. The diagnostic ratios method (Yunker et al. 2002; Mares and Pereira 2009; Szabo et al. 2012; Tobiszewski and Namiesnik 2012) is based on conservativeness of the chemical balance proportion of isomeric mass ratios of pollutants in sources and in the environmental samples; it is able to supply useful information and constitutes the most frequent method for source appraisal. The objective of the present study was to document the composition and distribution of PAHs, especially those listed by the USEPA with human carcinogenic or mutagenic effects, in the Almendares River, Havana, Cuba. We compare results from the present study to PAH levels reported in other rivers.
Materials and Methods Site Description Almendares River is the most important river of Havana, the capital city of Cuba. The river discharges an average of 15,576,000 m3 year-1 (0.53 m3 s-1) (Domı´nguez et al. 2004) of water from a 40,202 km2 drainage basin. Almendares River and its small tributaries run almost 6 km through the upper urban section of Havana. Through this route it receives numerous uncontrolled inputs from sewer
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and different factories (foods, pharmaceutical, paint, and electronics). The largest provincial Calle 100 landfill for solid-waste discharge lixiviates into the river. Pollutants as PAHs can reach the river through city runoff or atmospheric fall-out. Although the river has little waterfalls along its course, which may act to improve water quality, pollution levels are considerable. High values of chemical oxygen demand (2034 tons year-1) were recently determined (Alcolado-Prieto et al. 2012). Aquatic life in the river is scarce in general and practically absent in some intermediate places of the urban reach of the river. The average depth of the river is 0.62 m in dry season, and the width in all studied locations is approximately 7 m (Dominguez et al. 2004). The climate is subtropical with a dry winter and rainy summer season. The zone under study is located in approximately four densely populated municipalities. In Fig. 1, the localization of sampling sites is shown. Sample Collection River water samples were collected and stored as recommended by the American Public Health Association (2005). Sampling campaign was performed in March 2013 (dry season) to determine the worst-case scenario for organic contamination in river waters. Approximately triplicate 1000 mL samples of surface waters were collected in each of five sampling stations (Table 1) in previously cleaned amber flasks (1 L) and baked overnight at 400 °C. Before analysis, samples were filtrated using a 0.45 lm glass fiber filters. The sites of water sampling are listed in Table 1. Chemical and Reagents A standard solution, traceable to NIST containing 16 priority USEPA PAHs. Solid PAHs were received from Sigma-Aldrich. High-performance liquid chromatography (HPLC)-grade methanol, n-hexane, dichloromethane, and acetonitrile were purchased from Merck. Milli-Q-quality water was used in the analytical procedure. Analyticalgrade silica gel and alumina (100–200 mesh) were washed twice with dichloromethane and then baked at 250 °C for 12 h. Sodium sulfate was baked at 450 °C and then stored in sealed desiccators. Analytical Methods PAHs in water phase were concentrated by solid phase extraction in 1 g C18 cartridges from LiChrosorb, Merck. Before extraction, the cartridges were conditioned with 5 mL of methanol under vacuum conditions followed by 5 mL of ultra-pure water. After spiking with surrogate
Arch Environ Contam Toxicol
Fig. 1 Sampling stations localization in Almendares River for water analysis
Table 1 Locations of the sampling stations along the Almendares River No
Sampling sites
Position
Description
1
El bosque bridge
Latitude 23°, 060 , 30.100 ; longitude 82°, 240 , 26.400
Site is situated in a recreational parkland with vegetation along the sides
2
Puentes grandes
Latitude 23°, 050 , 30.100 ; longitude 82°, 240 , 55.300
Site is adjacent to a high-traffic road; road runoff discharges directly to river waters
3
Husillo bridge
Latitude 23°, 050 , 06.900 ; longitude 82°, 240 , 00.700
Site is covered by vegetation; detergent inputs cause a considerable stable foam formation on surface waters
4
Marinero
Latitude 23°, 030 , 58.000 ; longitude 82°, 240 , 14.800
Station is situated near the outfall of Calle 100 landfill lixiviates channel; under direct influence of aerosols and fumes from spontaneous fires from landfill
5
Calle Sur
Latitude 23°, 030 , 30.400 ; longitude 82°, 240 , 02.400
Site is situated in parallel with Calle 100 landfill near small farmer ranch; visible presence of oil spills in surface waters
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standards, a total volume of river water samples (1 L) was passed through the cartridges at flow rate of 5 mL min-1. The organic pollutants retained on the C18 cartridges were eluted with 6 mL of n-hexane. The sample extract was separated over 5 % alumina in silica gel mixed sorbent column, 5 % w/w H2O. The first fraction was eluted from the column with n-hexane (10 mL), and the second fraction was eluted with a mixture of 2:7 v/v n-hexane and dichloromethane (20 mL). The second fraction was concentrated in a micro Kuderna–Danish device to 1 mL. Qualitative and quantitative determination of PAHs was performed by HPLC with fluorescence detection (FLD). A Shimadzu 20 A T Series chromatograph with an automatic injector, a column oven, a quaternary flow pump, and a fluorescence detector was used. A C18 Phenomenex HPLC column (250 9 4.6 mm, id 5 lm) was used with a binary polarity elution gradient of 1.2 mL/min water (A) and acetonitrile (B), in a temperate column (40 °C). The gradient was as follows: 40 % of B held for 10 min, increased linearly up to 100 % after 35 min, held for 10 min, and decreased to 40 % to allow for equilibration before the next injection. Acenaphthylene was not evaluated in the samples because of its low fluorescence intensity. The recommended maximum excitation and emission wavelengths were employed for PAH detection (Titato and Lanc¸as 2006). Laboratory solutions software was used for data analysis. Calibration curves were built from 0.1 and 200 lgL-1 of standard solution containing the studied PAHs. Determination of detection limits (DL) and quantification limits (QL) were established from calibration curves. DL and QL were established from the analytical background response (y value, intercept value of regression curve) plus three times the SD of this response value (Miller and Miller 2002). Quality-assurance procedures included analysis of duplicates, blanks, blanks spikes, and matrix duplicates spikes. Replicate samples were analyzed for all collected samples from each station. Reagent blank and recovery procedures were analyzed simultaneously for every five samples. The accuracy of the analytical procedure was examined by recovering the PAHs that had been previously added in different amounts to river samples (Titato and Lanc¸as 2006). The final concentrations were corrected by surrogate recovery data. Analysis of Data The results of determinations (Table 2) were expressed as a means values in samples from each site with associated expanded uncertainty and calculated using K = 2 as a covertures factor according to EuroChem Guide (2002). Pollutant source appraisal was performed by diagnostic
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ratios method (Yunker et al. 2002). Principal component analysis (PCA) factor plotting was used to group similar sample composition sets. PCA of randomized concentration data were performed to identify the latent factors of results variability (factor loadings). Ecological Risk Determination Individual PAH potency equivalency factors (PEFs) relative to benzo(a)pyrene (BaP) were adopted for the assessment of seven carcinogenic PAHs (PAHscarcinogenic), i.e., benzo(a)anthracene (BaA), chrysene (Chr), benzo(b)fluoranthene (BbF), benzo(b)fluoranthene (BkF), BaP, indeno(1,2,3-cd) pyrene (InP), and dibenzo (a,h) anthracene (DBA). These factors were taken from the recommendations of Canadian Council of Ministers of the Environment (CCME) Declaration document (CCME 2010) and from Nisbet and LaGoy (1992) to estimate multicomponent PAH exposure in ecosystems. Individual carcinogenic PAH concentrations were multiplied by their toxic equivalent concentration factor and the result were summed up leading to total toxic equivalent concentrations (TTEC). For the ecological assessment, data were compared with reported Canadian Water Quality Guidelines values for BaP according to aquatic life protection criteria. In addition, chronic and acute toxicity exposition levels for aquatic life protection in the river were estimated according to the United States Environmental Protection Agency (2004) approach model of Equilibrium Sediment Benchmark calculation (USEPA PAH ESB).
Results and Discussion Calibration curves used for analysis presented correlation coefficients (r2 C 0.999) showing a good relationship between concentrations and fluorescence intensity in the studied range. Metrological limits were sufficiently low (0.25–8.1 ng L-1) to determine 14 PAH concentrations in all sampling stations. Acenaphthylene was excluded due to its low intensity florescence emission, and naphthalene was excluded due to low recovery values. The measured concentration of 14 individual PAHs and total PAH concentrations in water in the all sampling sites were tested for their distribution patterns using Kolmogorov–Smirnov test. The result shown the data were distributed according normal function, p B 0.05. PAH Concentrations in Almendares River Water PAH concentrations determined in the surface waters of Almendares River are listed in Table 2. The calculation of uncertainty of determinations was performed according to
Arch Environ Contam Toxicol Table 2 Determination of PAHs in Almendares River waters (ng/L) with associated uncertainties (K = 2) PAH
S1
S2
S3
S4
S5
Acenaphthene
190 ± 36
208 ± -40
449 ± -66
115 ± -26
1407 ± -102
Fluorene
185 ± -43
216 ± -37
563 ± -58
257 ± -65
2537 ± -226
Phenanthrene
242 ± -5
287 ± -34
1268 ± -137
950 ± -72
7337 ± -317
Anthracene
40 ± -8
46 ± -10
73 ± -14
180 ± -38
594 ± -92
Fluoranthene
43 ± -13
60 ± -15
249 ± -52
210 ± -47
1191 ± -118
Pyrene
45 ± -8
57 ± -12
487 ± -57
126 ± -27
1700 ± -189
Benzo(a)anthracene
17 ± -4
28 ± -5
53 ± -12
83 ± -15
104 ± -12
Chrysene
23 ± - 4
29 ± -4
178 ± -32
130 ± -19
681 ± -94
Benzo(b)fluoranthene
6 ± -2
12 ± -3
45 ± -8
37 ± -5
15 ± -5
Benzo(k)fluoranthene
8 ± -3
10 ± -2
37 ± -4
30 ± -4
26 ± -8
Benzo(a)pyrene Indeno(1,2,3-cd) pyrene
14 ± -5 4 ± -1
19 ± -5 6 ± -2
43 ± -5 22 ± -3
26 ± -4 7 ± -2
79 ± -18 18 ± -3
Dibenzo(a,h) anthracene
5 ± -2
6 ± -2
56 ± -4
15 ± -5
34 ± -6
Benzo(g,h,i)perylene
7 ± -4
5 ± -3
58 ± -6
19 ± -8
67 ± -10
RPAHs14
836 ± -178
1001 ± -137
3530 ± -458
2140 ± -337
15811 ± -1200
2 rings (%)
22
21
13
4
9
3 rings (%)
61
61
61
70
61
4 rings (%)
11
13
22
20
16
5 to 6 rings (%)
6
5
4
16
14
77 ± -1
80 ± -3
434 ± -68
339 ± -62
957 ± -146
RPAHscarcinogenic
Values represent means of at least three determinations in each site Table 3 Geometric mean values of total PAHs concentrations (ng L-1) in rivers worldwide Sampling sites
Mean
References
Mississippi River, USA
115
Zhang et al. (2007)
Seine River, France
20
Fernandes et al. (1997)
Slave River, Canada
29
McCarthy et al. (1997)
St. Lawrence River, Canada
326
Pham et al. (1999)
Yangtze River, China
491
Guo and co-workers (2012b)
Huaihe River, China
4385
Guo and co-workers (2012b)
Liaohe River, China Tianjins River
4021 35,000
Guo and co-workers (2012b) Cao et al. (2005)
Almendares River, Cuba
2784
This study
EuraChem Guide (2002). In Table 3, total PAH concentrations (geometric means) of some representative rivers in the world are listed. Total PAHs concentrations (RPAHs14) in dissolved phase ranged from 836 to 15,811 ng L-1. The average confidence interval for measured value (RPAHs14) in the five studied sampling stations achieved 15 % of central values. The geometric mean of RPAHs14 values in the present investigation was 2512 ng L-1 indicating the high pollutant level of river waters. The highest concentration corresponds to site 5. Relatively high content of 2-ring PAHs, which are well known for their lower persistence in aquatic ecosystems due to photolysis, degradation, and evaporation, among
other processes, possibly indicates a process that involves systematic and/or recent inputs of contaminants from petrogenic sources. PAH concentrations between the upstream sites (e.g., site 5) and the downstream sites are significantly different. Even when the pollutant concentration level is descending from upstream to downstream sites in a river, the hypothesis of dilution transport concentration of pollutant will be inadequate to describe the contaminant behavior in the river waters. In fact, among the low river flow of Almendares River, which allows PAHs to move from river waters to sediment or atmosphere phases, the presence of some small waterfalls, which improve the water quality in the Almendares River, contribute significant contaminant inputs of tributaries containing industrial discharges without treatment and high suspended particulate matter influents (e.g., site 4) affect the composition and total concentration of PAHs in Almendares River waters. These facts render difficult the analysis of probable dilution transportation model of PAH contamination from site 5. In average, [95 % of total PAH concentrations in a river is represented by 2- to 4- ring PAHs, which is consistent with their higher solubility in water. Specifically 3-ring PAHs were predominant (66 %). Phenanthrene was the predominant pollutant in the samples. As listed in Table 3, the Almendares River water PAH content is high. The PAH concentration levels found were
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higher than levels reported for some larger, navigable rivers such as the Mississippi, Seine, or Saint Lawrence rivers, belonging to developed countries with considerable industrial and energy production and fossil fuel consumption. Northern China rivers, immersed in highly polluted industrial environments, have higher pollutant concentrations than the Almendares River. A decreased amount of Cuban industrial production compared with those countries allow consideration that petrogenic inputs, such as industrial residual waters or oil spillage, are the main cause of the high pollution level present in more contaminated waters. Identification of PAH Sources The relative contributions of the major origins of PAH pollution was additionally estimated using factor analysis (PCA). PCA was also performed using a randomized data of PAH concentrations to determine significant factors. The initially obtained three factors with eigenvalues [1 were subjected to parallel analysis procedure using software ViSta v.7.9.2.5 (Ledesma and Valero 2007) to retain only the significant eigenvalues and their corresponding loading factors. Only two factors were significant in the parallel analysis. The obtained loading factors (Fig. 2) for each variable were used to characterize a possible pollutant source. Obtained factor scores show the variable’s behavior in each sampling station. Values for factor loadings and graphic representation of contribution of factors are shown (Fig. 2).
Fig. 2 Factor loadings and scores after PCA analysis
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Loadings for factor 1 characterize a petrogenic input. All of the sites, with exception of sampling site 4 (combustion source), were predominantly affected by a petrogenic source. Sites 3 and 5 were the best represented by this dominant petrogenic factor according to factor scores values. Stations 1 and 2 have a mixed influence from petrogenic and combustion sources. Factor 2 represents a combustion factor. The best represented stations were the stations 1 and 2. Factor-plotting analysis (Fig. 3) allows clustering of similar sites. In addition, it is possible to differentiate the petrogenic inputs in the sites. The diagnostic ratios method is used to distinguish the sources whether petrogenic and pyrogenic (combustion). PAHs in different environment media depend on thermodynamic properties similarities of isomers, such as partitioning and kinetic mass transfer coefficients and stability against photolysis (Yunker et al. 2002). This method is sustained on the assumption of conservativeness of different species’ isomeric ratios proportions in each evaluated source and its nonmodification from source and measurement points. Although it is recognized that before that source appraisal can be based on this, is not a robust enough asumption (Wagener et al. 2012); however, it is very useful method of probable source identification of PAHs. If the ratio of Ant/Ant ? Phe is [0.1, the source is usually assumed to be pyrogenic, whereas a ratio \0.1 suggests petroleum sources. However, for some specific
Arch Environ Contam Toxicol Fig. 3 Factors plot for sampling stations. Case F1 versus F2
fuels (diesel, used engine oil) the indicator must be[0.1. In our study, the values of the Ant/Ant ? Phe ratio were 0.2, 0.12, and 0.13 for sampling sites 1, 2, and 4, respectively, which allow their classified as being mainly affected by pyrogenic sources. Petroleum source was proposed for sites 3 and 5, where the indicator values were 0.05 and 0.07, respectively. Possible contributing sources of PAHs in the former sites (sites 1, 2, and 4) are the combustion of fossil fuels (industries and cars) and dry and wet deposition (atmospheric and road runoff). Additionally, site 4 s influenced by fumes, aerosols, and direct atmospheric depositions of combustion products from spontaneous fires of organic materials (wood, exhausted oils, and trees foliage among other flammable residues) from Havana landfill, which is located near this site. The Flu/(Flu ? Pyr) indicator values for site 3 occupies an intermediate position (0.35) between petroleum sources of PAHs and those corresponding to combustion products. It is probable that mixed sources can be responsible for PAHs presence in this sampling station. Attention must be paid to the relatively high contents of heavy PAHs compared with other sites as listed in Table 3. For site 5, a ratio of Flu/(Flu ? Pyr) \ 0.5 indicates a petroleum sources. This fact corresponds with the source identification described in previous text. The disposal of exhausted oils and petroleum derivatives is probably the main cause of higher PAH concentrations in the studied sites. According to Yunker et al. (2002), a ratio of BaA/ (Chr ? BaA) \ 0.2 indicates petroleum sources. Values between 0.2 and 0.35 indicate possible mixed sources
(petroleum and combustion contamination), and values [ 0.35 values indicate combustion sources. Similar behavior it is observed for ratio of indeno(1,2,3-cd) pyrene/ [indeno(1,2,3-cd) pyrene ? benzo(g,h,i)perylene] according to Yunker et al. (2002), Li et al. (2006), and Zhang et al. (2007). Taking into account the limitations of the diagnostic ratios methods already described, PCA was applied to obtain additional information from factor analysis. Two factors showed significant eigenvalues[1 according to the results of parallel analysis (Fig. 2). Composition of factor 1 must be associated with petrogenic input and explains 51 % of the total variance (Fig. 2). The sites 3 and 5 are the best represented by this factor, but the contribution of this factor is not negligible in sites 1 and 2. This fact was expected and is consistent with the visual diagnostic record of sampling procedure listed in Table 1. There is a complete correspondence with the results of the diagnostic ratio method, which identified a dominant petrogenic pollution source in sites 3 and 5. For sampling site 2, intermediate results between petrogenic and combustion sources are shown due to fluctuating results from the different observations (n = 4, 5, and 6 observations in the same sampling site). This result is consistent with previous pollutant source identification by the diagnostic ratio method (Table 4). Explanation of this experimental fact must be founded in water sampling in a river with low, nonturbulent water flow that receives inputs from different sources without adequate mixing process. Factor 2 has positive loadings for light and heavy PAHs with increased thermodynamic stability and must be associated with combustion pollution sources. This factor
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Arch Environ Contam Toxicol Table 4 Site-specific results for diagnostic ratios source appraisal method Station
Ant/(Ant ? Phe)
BaA/(Chr ? BaA)
Flu(/Flu ? Pyr)
InP/(InP ? BgP)
Criterion
1
0.14
0.48
0.43
0.4
C
2
0.86
0.5
0.49
0.5
C
3
0.05
0.34
0.23
0.16
P
4
0.16
0.62
0.39
0.26
C
5
0.07
0.4
0.13
0.21
P
Sources*
[0.1 combustion (C)
\0.2 petroleum (P)
\0.4 petroleum (P)
\0.2 petroleum (P)
\0.1
\0.2 \ x \ 0.35 mixed (M)
\0.4 \ x \ 0.5 combustion
\0.2 \ x \ 0.5 combustion
Petroleum P
[0.35 combustion
[0.5 coal, wood comb
[0.5 coal, wood comb
* Yunker et al. (2002), Li et al. (2006), and Zhang et al. (2007)
explains 32 % of the total variance. The sites with better representation by this factor are sites 1 and 2. PCA analysis (factor plotting) allows clustering of the sites with the same composition pattern under influence of different sources considering the pollution contributions from different sources in a complex river system (Fig. 3). Analysis of factors plots showed four groups of sampling stations differentiated by the results of factor 1 and 2 ratios. Sampling stations 3 and 5 were predominantly affected by petrogenic input. Stations 1 and 2 have similar positions, indicating a similar composition for both sites, largely influenced by petrogenic and combustion processes. It is possible to differentiate in these sites (sites 1 and 2) recent petrogenic inputs due to the presence of lighter weight PAHs from the oldest one, which is present in stations 3 and 5. Sampling station 4 presents the most dispersive cluster possibly due to the influence of high particulate matter content in water samples due to landfill proximity and its influence in the determination of individual components. The same cause is responsible for the ambiguity in source identification using PCA at the same station due possibly to pattern typology changes.
Fig. 4 Total toxic equivalent concentrations (TTEC) in the five sampling stations for water quality monitoring in Almendares River. The results are expressed in ng BaP eq. L-1. Critical reference value: 15 ng L-1 (CCME, 2010)
Ecological Risk Determination The values of total toxic equivalent concentration for the studied sites are shown in Fig. 4. The calculated results for model of the equilibrium sediment benchmark calculation (USEPA PAH ESB) procedure for acute and chronic exposition of aquatic life in the Almendares River are shown in the Fig. 5. The highest PAH concentrations were found in site 5, which is in correspondence with visibly the more deteriorated ecosystem due to oil spillage inputs from industrial sources. The lowest PAH concentrations were found in site 1 corresponding to recreational activities. Regarding risk assessment, in all cases the achieved values were [0.015 lg L-1, which is the recommended
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Fig. 5 EPA PAHs ESB results for acute (black color columns) and chronic (grey color columns) toxicity values for aquatic life in the Almendares River. Critical reference value: 1 lgL-1
value for BaP concentration in Canadian Water Quality Guidelines, or 0.0038 and 0.018 lg L-1 for chronic and acute human safety exposition in freshwaters systems, respectively, according to USEPA. Acute toxicity values
Arch Environ Contam Toxicol
(black column values in Fig. 5) exceed the permissible value of 1 in sites 3, 4, and 5. In site 5, the proposed limit value exceeds [10 times that of the analyzed waters. Concerning chronic exposure, only station 5 is affected according to the determined pollutant concentration.
Conclusion The present study provided important data on the occurrence, distribution, and source apportionment of PAHs in the surface waters of Almendares River. To minimize the uncertainties in pollution source identification and to obtain a better description of all possible inputs influences in the river, diagnostic ratio analysis and PCA factor analysis were applied to estimate source contributions for water PAH contamination. The derived individual diagnostic PAH ratios suggested that important contribution for this pollution has come from petrogenic activity. Consistent with the aforementioned method, similar conclusions were achieved applying PCA analysis for randomized samples. The identification of major emission sources is an essential step in seeking to control, manage, and ameliorate environmental pollution. Regarding ecological risk assessment, it was undertaken to study the potential ecological risk induced by seven carcinogenic PAHs in Almendares River surface water. The results of this study indicate that despite probable uncertainties common in toxicity risk assessment, these results could be useful for the identification and management of ecological risk posed by PAHs in surface water, and mitigation efforts should be considered in the near future. Acknowledgments The authors are grateful to Coordinac¸ao de Aperfeic¸oamento de Pessoal de Nı´vel Superior for supporting determinations and discussion of obtained results through CAPES-MES project 149/12.
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