Characterization of soil remediation workers’ dermal exposure
to polycyclic aromatic compounds
Beatrice Johansson
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are organic compounds that are composed by at least two aromatic rings. PAHs can be found in coal and petroleum, but can also be formed from incomplete combustion of for example fossil fuels, tobacco, wood and when smoking food. PAHs has been shown to cause several health risks such as carcinogenic effects, which led to that the U.S Environmental Protection Agency (U.S. EPA) selected 16 PAHs as priority pollutants. Those 16 PAHs is usually analysed when investigating PAH exposure. To analyze dermal exposure of PAHs a tape-stripping technique can be used. The tape-stripping method involves that a tape piece is placed on the skin to absorb the present PAHs and then the tape is removed and the PAHs can be extracted and cleaned-up from the tape. The aim of this study is to optimize a recently elaborated clean-up method for PAHs sampled by the tape-stripping technique. Also, to apply the method and measure the dermal exposure of 16 PAHs among soil remediation workers.
Two clean-up methods were evaluated, Florisil SPE columns and deactivated silica (10%). Clean-up using Florisil columns were evaluated using 10 and 12 ml of n-hexane. For elution, poor recoveries were achieved for both elution volumes tested. On the other hand, tests using deactivated silica generated good recoveries for both elution solvents tested (i.e. 4 ml n-hexane:dichloromethane + 4 ml dichloromethane and 8 ml n-hexane). As for the elution solvents, no significant difference could be seen in the recoveries and the mixture of n-hexane and dichloromethane was used for the real samples. The dermal exposure of PAHs for the soil remediation workers were investigated using dermal tapes from the palm and neck of 18 soil remediation workers. Samples from the palm were sampled before and after a working day and there was a small difference between the total PAH concentration before and after a work-shift. For all categories of workers (office staff, machine operators and persons performing sampling) an increase in dermal concentration of PAHs could be observed for ten of the workers, but this increase were highest among the workers active in taking samples at the contaminated site. However, an increase in PAH exposure was not observed for all study participants and possible this is due to hand-washing after toilet visits. Overall, the concentrations of PAHs on the dermal samples from soil remediation workers were low, especially in comparison to other occupations such as chimney sweeps and pavers where PAH exposure is known to exist. The detected PAHs on the dermal tapes corresponded to PAH profiles in soil samples from the site.
Table of content
Abstract ...
1. Introduction ... 1
1.1 Polycyclic aromatic hydrocarbons ... 1
1.2 Creosote ... 1
1.3 Dermal exposure and previous studies ... 2
1.4 Objective ... 3
2. Materials and method ... 3
2.1 Chemicals, standards and materials ... 3
2.2 Method development ... 4
2.2.1 Preparation of tapes and dermal sampling... 4
2.2.2 Extraction ... 4
2.2.3 Clean-up methods ... 5
2.2.4 Transfer of extract to GC vials ... 6
2.3 Samples from soil remediation workers... 6
2.3.1 Sampling ... 6
2.4 Instrumental analysis ... 7
2.5 QA/QC ... 7
2.6 Calculations ... 7
3. Results and discussion ... 8
3.1 Method development ... 8
3.2 Soil remediation workers ... 9
4. Conclusion ... 15
References ... 16
1
1. Introduction
1.1 Polycyclic aromatic hydrocarbons
Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds that is characterized by two or more aromatic rings. PAHs are formed by incomplete combustion or pyrolysis of organic materials such as fossil fuels, wood, tobacco and in cooking process of food, especially in fried and smoked food. PAHs can also be found in tar and mineral oils (Kammer, Tinnerberg and Eriksson, 2011). Several PAHs has been classified as carcinogenic to humans by The International Agency for Research on Cancer (IARC). This due to that studies have shown that workers occupationally exposed to PAHs in various industries, by ingested, inhaled or dermal exposure, have an increased risk of developing for example skin, lung, laryngeal and urinary bladder cancer (Bosetti, Bofetta and La Vecchia, 2005). U.S. Environmental Protection Agency (U. S. EPA) have selected 16 PAHs as priority pollutants which are usually analyzed when PAH exposure is suspected. Three of these 16 PAHs were selected because they were included in “the original list of 65 toxic pollutants”, which is a set of different chemical pollutants that are regulated by the U.S EPA. The list was an initiative to ensure good water quality in drinking water. A lot of petrochemicals industries were located nearby rivers and water sources and the PAHs were known to have carcinogenic effects, therefore PAHs were added to the list, to be on the safe side (Keith, 2015). Seven of them where included in the 16 priority PAHs partly because analytical standards were available. Three additional PAHs were selected due to that they were suspected to be carcinogens in water supplies. Regarding the remaining three PAHs, two was chosen because those compounds were often used in dyes as a chemical intermediate and the last one due to it represent PAHs composed of six rings (Keith, 2015). These 16 PAHs can be divided into subgroups, for example PAH-L, PAH-M and PAH-H which stands for PAHs with low, mid and high molecular weight respectively. Transport and distribution of PAHs in the environment are depending on their chemical and physical properties. In general, PAHs with low molecular weight are more water-soluble and volatile, and are distributed in soil and groundwater more readily (Naturvårdsverket, 2011). They occur in the atmosphere mainly as vapors. Volatility and solubility in water tend to decrease with increasing molecular weight of the compound while the solubility in fat increases. High molecular weight PAHs exist therefore mainly adsorbed to particles in the environment (air, water and soil), and are therefore less available for degradation processes.
1.2 Creosote
In distillation of coal tars and coal tar pitchers one main fraction is creosote, which is a mixture of many chemicals but the main component are aromatic compounds and phenols (Kemikalieinspektionen, 2017). At least 75% of the creosote content is PAHs, based on weight (Bofetta, Jourenkova and Gustavsson, 1997). Creosote has been used as a preservative for wood, in for example railway sleepers and telephone poles, which is the only allowed area to use creosote in Sweden today. Usage on a workplace also requires a professional worker with specialist training (Kemikalieinspektionen, 2016). As a consequence of this preservative usage, several areas are contaminated with creosote and PAHs (Eriksson et al. 2001). Because of the toxic properties of PAHs those areas are highly prioritised for remediation. Concentrations and composition of PAHs in contaminated areas are related to the history of contamination, the availability and the degradability of the compounds. Availability and degradability of PAHs in soil commonly decrease with time, a phenomenon referred to as aging (Alexander, 2000). In Ruby et al. (2016) it’s reported that soil contaminated with coal tar and that aged 110 days had an approximately two-fold reduction in availability of benzo(a)pyrene. The fraction of bioavailable PAHs will reduce over time due to diffusion of the PAHs in to the soil particles.
2 1.3 Dermal exposure and previous studies
The area of interest in this project is an old railway depot where impregnation of for example railway sleepers with creosote oil has been going on for 75 years. This lead to one of the largest remediation projects in Swedish history which took two years to finish (Trafikverket, 2017). During the summer of 2016 samples were collected from the area (i.e. soil and air samples) and from the soil remediation workers (dermal, blood and urinary samples). There are some methods for measuring dermal exposure of PAHs, for example washing of the skin or fluorescent techniques, which use a fluorescent tracer and by measuring at the emitted light it’s possible, with a software, to look at concerned dermal areas and exposure (Cherrie et al., 2000). These methods give a good estimation of the presence of PAHs on the skin but cannot quantify the actual exposure. A method that can remove the significant compounds on the skin and at the same time include the outermost skin layer is a tape-stripping method. Tape stripping is a technique were a piece of tape is placed on the skin and left for one minute to bind PAHs from the skin. The PAHs are extracted from the tape piece, usually by an organic solvent. The extract undergoes sample clean-up and is then analyzed (Kammer, Tinnerberg and Eriksson, 2011).
There is none, to my knowledge, published method where the tape-striping technique of analyzing dermal exposure of PAHs has been analyzed by gas chromatography (GC). Using GC-MS will enable analyzing all 16 PAHs at the same time but also make it possible to detect and identify other polycyclic aromatic compounds. Consequently, GC-MS is overall a good method to analyze PAHs with. One study combined tape-striping and analysis using high-performance liquid chromatography (HPLC) to investigate dermal exposure of pyrene and benzo(a)pyrene among chimney sweeps (Kammer, Tinnerberg and Eriksson, 2011). The results from the study showed detectable levels of both pyrene and benzo(a)pyrene, where the levels of pyrene after a work shift ranged from 2.1 to 6.3 ng/cm2 for the back of the hand and lower
arm. Benzo(a)pyrene levels, on the same dermal areas, ranged from 0.3-3.3 ng/cm2 for chimney
sweepers after a work day. The results also showed that tape stripping can be used to determine the dermal exposure of pyrene and benzo(a)pyrene with HPLC.
In a study by Dor et al. (2000) the dermal exposure of pavement workers was investigated using reversed phase HPLC and fluorometric detection. To sampling the workers got to wear pads with a monitoring surface at their center at five different body locations during an 8 hours work shift. The workers were placed at three previous manufactured gas plant sites, at different locations but all in the metropolitan area of Paris, where they were supposed to pavement-cover the soil. The study showed that the workers that worked outdoor all the time had PAH contamination above the detection limit. None of the two other working groups, mixed (i.e. subjects working outside part of the time and inside part of the time) and office (i.e. workers that spent all their work time inside) had detectable PAH contamination on any of the sampling sites (Dor et al., 2000).
Another study investigating road pavers’ dermal exposure of PAH with two different methods, exposure pads (pads were worn during whole work shift and were supposed to absorb the PAHs similar to the skin) and a hand-washing method, were the workers’ hands were washed with sunflower oil and paper tissue (Väänänen et al., 2005). Sampling were done at six paving sites and samples from the road pavers was taken both pre- and post-shift. At each paving site, seven different job assignments existed divided on four to nine workers. Six of the seven assignments were in direct contact with the paving site while the last assignment guided the passing traffic which led to that this worker was further away from the paving site. The results from this study by Vännänen et al. (2005) showed a significant difference in PAH concentrations in the before
3 and after shift samples by both methods. The report also revealed that the six of the seven job assignments that were in direct contact with the paving site had an exposure of PAHs 40 times higher than the workers that were further away from the paving site (Väänänen et al., 2005).
1.4 Objective
The aim of this study is to develop a recently elaborated method for GC-MS analysis of the US EPA 16 PAHs on tape-stripping samples. Also, to measure the dermal exposure of the 16 PAHs among soil remediation workers during the remediation of a large creosote contaminated area.
2. Materials and method
2.1 Chemicals, standards and materials
The organic solvents used were dichloromethane and toluene from Scharlau (Sentmenat, Spain) of HPLC grade, n-hexane with 98.0% purity SupraSolv® from Merck Millipore (Darmstadt, Germany) and acetonitrile of HPLC grade from Fisher Scientific (Loughborough, UK).
All standards used were supplied from Dr. Ehrenstorfer GmbH (Augsburg, Germany) and had 98% purity. The internal standard (IS) used where a deuterium-labelled mixture of 16 PAHs, abbreviated PAH-Mix 9, which can be seen in Table 1.
Table 1. Product name of internal standards (IS) with number of deuterium labelled hydrogens and mass to charge (m/z) for the molecule.
As recovery standard (RS) deuterium labelled perylene was used with a purity of 98,1%. A mixture of native PAHs, called PAH-Mix 45, was used as quantification standard and had a purity of 98%. Chemicals included in the PAH-Mix 45 are presented in Table 2.
Table 2. Product name and CAS number for native compounds included in the PAH-mix 45.
Product name m/z CAS-number Purity (%)
Acenaphthene 154 83-32-9 99.500
Acenaphthylene 152 208-96-8 99.000
Anthracene 178 120-12-7 98.500
Product name m/z CAS-number Purity (%)
Acenaphthene D10 164 15067-26-2 99.000 Acenaphthylene D8 160 93951-97-4 98.000 Anthracene D10 188 1719-06-8 98.500 Benzo[a]anthracene D12 240 1718-53-2 98.500 Benzo[b]fluoranthene D12 264 99.000 Benzo[k]fluoranthene D12 264 99.000 Benzo[g,h,i]perylene D12 288 93951-66-7 99,000 Benzo[a]pyrene D12 264 63466-71-7 99.000 Chrysene D12 240 1719-03-5 98.500 Dibenzo[a,h]anthracene D14 292 99.000 Fluoranthene D10 212 99.500 Fluorene D10 176 81103-79-9 99.000 Indeno[1,2,3-c,d]pyrene D12 288 99.800 Naphthalene D8 136 1146-65-2 99.300 Phenanthrene D10 188 1517-22-2 99.500 Pyrene D10 212 1718-52-1 99.500
4 Benz[a]anthracene 228 56-55-3 98.700 Benzo[b]fluoranthene 252 205-99-2 99.900 Benzo[k]fluoanthene 252 207-08-9 99.000 Benzo[g,h,i]perylene 276 191-24-2 99.600 Benzo[a]pyrene 252 50-32-8 99.000 Benzo[e]pyrene 252 192-97-2 98.500 Chrysene 228 218-01-9 99.000 Dibenz[a,h]anthracene 278 53-70-3 99.800 Fluoranthene 202 206-44-0 98.500 Fluorene 166 86-73-7 98.000 Indeno[1,2,3-c,d]pyrene 276 193-39-5 98.900 Naphthalene 128 91-20-3 99.900 Perylene 252 198-55-0 99.500 Phenanthrene 178 85-01-8 98.000 Pyrene 202 129-00-0 99.000
Fixomull tape from BSN medical GmbH & Co (Hamburg, Germany) was used for sampling dermal samples in this project. For the solid phase extraction (SPE) Florisil columns (Isolute FL 500 mg/3 ml; Biotage, Uppsala, Sweden) were used and for the mini-silica columns Silica gel 60 mesh was supplied from Sigma Aldrich (Stockholm, Sweden).
2.2 Method development
2.2.1 Preparation of tapes and dermal sampling
Tools such as scissors and tweezer, were rinsed with 70 % ethanol before use. Pieces of fixomull tape was cut in 35 cm each and were used to tape the skin. Tape was applied on the inside of the right forearm, the left side of the neck, the right ankle and in the right palm on non-exposed persons, then rubbed three times back and forth before they were removed with tweezer and placed in scintillation vial. On each skin surface, the taping was done in triplicate and three blanks without skin matrix were also prepared. The skin samples were stored in scintillation vials in a freezer until sample preparation. During the second method trial, five dermal samples were taken from each forearm of a non-exposed person.
2.2.2 Extraction
Prior to extraction the samples and IS were let to stand in room temperature for 30 minutes before 25 µl of IS was added on each tape. After another 30 minutes 5 ml of acetonitrile (ACN) was added to each sample and the vials were let to stand in ultrasonic bath for 20 minutes. The ACN was transferred to a glass centrifugation tube and an additional volume of 5 ml ACN was added to each sample and extraction using ultra-sonication was repeated. The solvent of each sample was combined with the first fraction. The ACN was removed by placing the glass centrifugation tubes in a vacuum centrifuge were the samples were evaporated to complete dryness. The vacuum centrifuge was pre-heated to 36 °C and a 42 minutes long program with heating the first 36 minutes was used. Pressure (P) was held at Pmin. (i.e. approximately 8 mbar).
The evaporation cycle was extended by use of shorter programs to completely remove all ACN, i.e. run in steps of 7 (at 36 °C) respectively 10 minutes (at 38 °C). Temperature had to be increased to 38 °C to evaporate the solvent in some samples. When no ACN was left in the glass vials a small volume of n-hexane were added immediately to resolve the analytes.
In the second method trial, four of the samples were extracted with acetonitrile and for the six remaining samples, an extraction with 5+5 ml of n-hexane: dichloromethane (9:1) was tested.
5 This test of using another extraction solvent was due to that with hexane:dichloromethane it’s not necessary to evaporate to complete dryness before the sample clean-up which will shorten the evaporation time and thereby increase the chance of getting a better recovery for the more volatile PAHs, i.e. PAHs with low and mid molecular weight. The samples that were extracted with n-hexane:dichloromethane were evaporated under a gentle flow of nitrogen while the acetonitrile extracts were evaporated in the vacuum centrifuge. The extended time of the evaporation procedure was approximately 30 minutes in steps of 2 to 7 minutes.
2.2.3 Clean-up methods
Skin samples might contain residues from for example old skin, fat and skin lotion which may affect the results of the analytical procedure. To minimize those influences the samples must go through a sample clean up step. In this study two different clean-up methods were evaluated; first solid phase extraction was applied and secondly a clean-up step using deactivated silica was tested.
The SPE was performed using Florisil columns. The cartridge was washed with 6 ml of a mixture of n-hexane and dichloromethane (1:1 v/v) at a flow rate of 1 drop/sec. The sample were loaded into the cartridge and the tube were washed with a small amount of n-hexane three times which were transferred to the SPE cartridge. The flow was adjusted to 1 drop/sec and n-hexane were used to elute the PAHs from the cartridge, the column was never let dry. Two different elution volumes, 10 and 12 ml, were tested to optimize the extraction of PAHs. All samples were then evaporated down to a volume of approximately 0.7 ml by the use of a vacuum centrifuge. The vacuum centrifuge was pre-heated to 36° C, then a 35 minutes long program with heating the first 30 minutes and a pressure at P=180 mbar was set. The evaporation program had to be extended for both validation trials, first 15 minutes with heating during the whole session and then with 9 minutes with heating for the first 7 minutes.
In the second method trial, clean up was done on 10% deactivated silica columns instead of Florisil columns. Pasteur pipettes were plugged with glass wool and then filled with 4 cm of 10% deactivated silica. Shortly after the preparation of the columns, n-hexane were added to wash the silica and also to prevent further deactivation of the silica. The samples were loaded on the silica and the centrifuge tubes were washed three times with small volumes of n-hexane that were transferred to the silica. Analytes in five of the samples (two of the acetonitrile samples and three of the hexane:dichloromethane samples) were eluted with 8 ml of n-hexane while PAHs in the other five samples were eluted with 4 ml of n-hexane:dichloromethane (3:1 v/v) and 4 ml of dichloromethane (Figure 1).
6
Figure 1. A schematic picture of the second method trial showing an overview of the different extraction solvent used (ACN and n-hexane: dichloromethane (9:1)), and the different elution solvents tested during the sample clean-up (8 ml of n-hexane and 4 ml of n-hexane: dichloromethane plus 4 ml of dichloromethane).
The samples eluted with 8 ml of n-hexane were evaporated in the vacuum centrifuge while the other samples (eluted with 4 ml n-hexane:dichloromethane plus 4 ml dichloromethane) were evaporated under a gentle flow of nitrogen down to approximately 0.7 ml. The program set for the vacuum centrifuge followed the protocol.
2.2.4 Transfer of extract to GC vials
All extracts were transferred to v-vials and the centrifuge tubes were washed three times with a small amount of n-hexane which were transferred to the corresponding v-vials. The n-hexane were evaporated under a gentle flow of nitrogen down to a volume of 50 µl and a small amount of toluene (5 drops with a Pasteur pipette) followed by 25 µl of recovery standard (RS) were added to each sample. A total volume of 100 µl were obtained by letting the samples evaporate in the fume hood. However, the extracts from extraction using n-hexane:dichloromethane could not be transferred to v-vials due to their very viscous character and they were discarded from the method development protocol.
2.3 Samples from soil remediation workers
2.3.1 Sampling
Samples from remediation workers had already been collected during summer 2016 using the same procedure as described for the samples used in the method development. From the remediation workers’ the following samples were included in the study: one field blank, 18 samples from palm collected before start of the working day, 18 samples from palm after the end of the working day and 14 samples from neck taken after the end of the working day. Assignments among the workers differed, and were for example, sampling of soil or water, machine operator or desk staff. Only the workers’ dermal exposure was investigated in the present study. The samples taken in palm before working day was analyzed as a “zero-sample” and the sample after working day from palm was chosen to be able to directly compare the zero samples. The neck samples were chosen due to that the neck might not be so covered by protective clothing as other parts of the body, and could therefore possible be a high contaminated area.
ACN were used as extraction solvent for the samples from the soil remediation workers and extraction followed same procedure as described in first part of 2.2.2 Extraction. Clean-up was
7 performed on deactivated silica following the protocol described in second part of 2.2.3 Clean-up methods, using hexane: dichloromethane and dichlorormethane (4+4 ml) as elution solvents. All samples were evaporated under constant flow of nitrogen to a volume of approximately 0.7 ml. The remaining sample preparation before GC/MS analysis followed the same procedure as previously described in the method development part.
2.4 Instrumental analysis
Quantification of 16 PAHs were done by use of an Agilent 6890 Series gas chromatography system coupled to a 5973-mass selective detector, equipped with a DB-5MS column (30m0.250mm, 0.25µm film thickness; Agilent Technologies, Part number 122-5532). Electron ionization (EI) was used as ionization technique. A constant flow of 1.1 ml/min was held for the helium gas. For the GC oven, the following temperature program was set; 90 °C (hold for 2 min), 8 °C/min to 300 °C (hold 7 min). Post temperature was 310 °C (hold 5 min). Injection were done in splitless mode with an injection volume of 1 µl. Single ion monitoring (SIM) mode was used to detect the PAHs.
2.5 QA/QC
Quantification of the analytes was performed by use of the isotopic dilution method, using deuterium-labelled IS and RS. In lack of internal standard, the IS nearest in retention time was used to calculate the relative response factor (RRF) for the analyte. Deuterium labelled RS was used for calculation of the recovery and recoveries should be in a range of 50-120%. Quantification standards (QS) were analyzed after every tenth sample followed by a method blank. The limit of detection (LOD) was calculated from the mean concentration of five method blanks + three times standard deviation. A field blank was taken to evaluate possible contamination during sampling and a method blank without skin matrix were run with each batch.
2.6 Calculations
To quantify the concentrations of PAHs, isotopic dilution was used. The relative response factor (RRF) was calculated for each compound by following formula:
𝑅𝑅𝐹 = 𝐴𝑟𝑒𝑎𝐴𝐶𝑜𝑛𝑐𝐼𝑆 𝐴𝑟𝑒𝑎𝐼𝑆𝐶𝑜𝑛𝑐𝐴
Where AreaA is the peak area of the native compound in the quantification standard and ConcA
stands for the concentration of the native compound in the quantification standard. AreaIS and
ConcIS is the peak area and concentration of the deuterium labelled standard in the
quantification standard.
Total concentration of PAHs in the sample can then be calculated using the RRF values and following formula:
𝐶𝑜𝑛𝑐𝑠𝑎𝑚𝑝𝑙𝑒 =
𝐶𝑜𝑛𝑐𝐼𝑆𝐴𝑟𝑒𝑎𝑠𝑎𝑚𝑝𝑙𝑒
𝐴𝑟𝑒𝑎𝐼𝑆𝑅𝑅𝐹 𝑐𝑚2
The results from this calculation is given in ng/cm2 and correspond to how many ng of the
compound that were present on each square centimeter of tape piece. Areasample is the peak area
8 labelled standard in the sample. RRF for respectively compound is given from the calculation above and square centimeters indicates the area of the tape piece. In this case the tape pieces are 15 cm2 (35 cm).
3. Results and discussion
3.1 Method developmentThe results from the method development are shown in Table 3, which displays the recovery for PAHs in six samples and one blank that have been cleaned up using Florisil columns and eluted with 10 ml of hexane. In Table 1-appendix, the recovery for PAHs in the samples eluted with 12 ml is presented.
Table 3. Recovery of deuterated PAHs from clean-up using Florisil columns and 10 ml n-hexane as elution solvent. Zero values are set when no recovery could be obtained. Recovery between 50% and 120% is good and is shown in green, yellow represents moderately good recovery between 20-50% and 120-150% and anything outside those values will be red and show a poor recovery.
Recovery Blank #3 Palm #1 Palm #3 Forearm
#1 Neck #1 Neck #2 Ankle #1
Naphthalene-D8 1.4 6.3 7.3 7.5 3.2 1.2 5.3 Acenaphthylene-D8 25 32 33 31 24 19 25 Acenaphthene-D10 23 28 30 28 23 19 22 Fluorene-D10 70 75 78 81 65 60 60 Phenanthrene-D10 56 56 59 56 49 50 45 Anthracene-D10 40 38 41 37 34 35 33 Fluoranthene-D10 50 50 47 45 39 38 36 Pyrene-D10 54 50 51 45 42 42 39 Benzo[a]anthracene-D12 69 69 70 69 52 49 47 Chrysene-D12 42 45 41 43 32 29 27 Benzo[b]fluoranthene-D12 10 79 22 81 4.7 4.4 7.0 Benzo[k]fluoranthene-D12 9.1 46 17 44 2.5 1.7 3.1 Benzo[a]pyrene-D12 1.5 65 7.7 69 0 0 0 Benzo[g,h,i]perylene-D12 0 57 0 73 0.4 0 0 Indeno[1,2,3-c,d]pyrene-D12 0 51 0.5 60 0 0 0 Dibenz[a,h]anthracene-D14 0 51 0 86 1.6 0 0
The two different elution volumes, 10 and 12 ml, were tested to optimize recovery of PAHs with high molecular weight, especially. When the method was previously developed, tape samples without skin matrix were used and cleaned up was performed using Florisil columns, which resulted in good recoveries for most of the PAHs (except naphthalene and acenaphthylene). However, when applying the method on real samples poor recoveries were encountered when skin matrix was present. Results from the method validation in this study, also showed poor recovery for many of the compounds in presence of skin matrix and no significant difference could be seen between the two elution volumes that were tested. The low recovery of high molecular weight PAHs might be due to matrix effects such as fat residues from the skin, which affected the elution efficiency of the PAHs from the columns. Skin is a complex matrix and contain most likely both non-polar and polar interferences which are probably not efficiently removed when using Florisil during the clean-up step. This could be seen in the chromatograms where there were a lot of background noise and the integration of the peaks became harder. It would have been interesting to test a GC-HRMS to try and identify the possible source of contamination, since GC-HRMS give the opportunity to look at much more accurate masses. A tandem MS would perhaps also have lowered the background noise.
9 For the samples purified on deactivated silica, the recoveries (19-111%) were overall much better, see table 4. No significant difference could be seen between the two elution solvents tested (i.e. 8 ml of n-hexane or 4 ml n-hexane:dichloromethane followed by 4 ml of dichloromethane).
Table 4. Recovery of deuterium-labeled PAHs from the four samples extracted with ACN and cleaned up on 10% deactivated silica columns. Sample 1 and 2 are eluted with 8 ml of n-hexane while sample 3 and 4 is eluted with n-hexane: dichloromethane plus dichloromethane (4+4 ml).
Recovery Sample 1 Sample 2 Sample 3 Sample 4
Naphthalene-D8 37,7 44,5 95,2 18,9
Acenaphthylene-D8 n.a.* n.a.* n.a.* n.a.*
Acenaphthene-D10 70,7 59,1 55,8 48 Fluorene-D10 77,4 64,4 84,9 77,8 Phenanthrene-D10 81,6 67,5 68,9 70,1 Anthracene-D10 55,7 61 60,5 59,5 Fluoranthene-D10 93,5 81,2 83,9 81,7 Pyrene-D10 98,4 82,9 82 81,4 Chrysene/benzo(a)anthracene-D12a 108 93,6 98,5 105,5 Benzo(b)fluoranthene-D12 99,2 84,1 95,9 93,5 Benzo(k)fluoranthene-D12 94,9 84,4 93 88,3 Benzo(a)pyrene-D12 90,9 84 94,7 82,1 Benzo(g,h,i)perylene-D12 104,1 88 106,6 98,4 Indeno(1,2,3-c,d)pyrene-D12 110,6 80,6 101 90,7 Dibenz(a,h)anthracene-D14 n.a.* n.a.* n.a.* n.a.*
*not analyzed.
a Benzo(a)anthracene-D12 and chrysene-D12 co-eluted for both internal standards and native compounds,
therefore the recovery is based on both standards, integrated as one peak.
Due to the good recovery of most PAHs (Table 4), the deactivated silica was used as clean-up method for the samples from the soil remediation workers. Since no distinct difference was seen in recovery regarding the two elution solvents, 4 ml of n-hexane:dichloromethane (3:1) followed by 4 ml of dichloromethane were used to enable quantification of oxy-PAHs in future studies.
3.2 Soil remediation workers
The recovery of the deuterium labelled naphthalene in samples from the soil remediation workers varied between 0.5-43%. A recovery below 20% is considered very poor and therefore the results of naphthalene in most of the samples is not reliable. Naphthalene is a volatile compound, which can explain the poor recovery, and naphthalene was because of this excluded from further calculations. The deuterium labelled acenaphthylene and dibenzo[a,h]anthracene were not included in the SIM method so consequently no recovery can be presented for these compounds. Since no recovery was obtained for acenaphthylene and because this compound, as well as naphthalene, is volatile, a poor recovery is expected and acenaphthylene was also excluded from further calculations.All samples from the soil remediation workers, except five samples showed a good recovery (50-120%) for almost all remaining compounds (appendix-Table 3), with a few exceptions for acenaphthene-D10 in some samples that had a moderate recovery (i.e. 24-50%). Recoveries were on the other hand very high in two samples, #20 after working day and #21 before working day (appendix-Table 4), which can for example be due to co-elution of interfering compounds. Fluorene-D10 was included in the recovery calculations but the native fluorene was analyzed in the wrong SIM time window and couldn’t be quantified in the samples. If there would had been more time the samples would have been reanalyzed on
10 the GC-MS to enable quantification of fluorene. Due to the poor recovery (0.4-43%) of all compounds in sample #20 collected before the working day, the result for this samples should be taken as an estimation of the dermal PAH exposure.
Concentrations of PAHs were detected in all method blanks, and naphthalene was present in highest concentration, but was excluded from further calculations due to its poor recovery. Low concentrations of PAHs were detected in all blanks, especially for acenaphthene, phenanthrene and benzo(b,k)fluoranthene, but remaining compounds could also be detected but in even lower concentrations. From the five method blanks LOD was calculated and is presented in Table 5.
Table 5. LODs calculated as the mean blank concentration plus three times standard deviation for all five blanks.
Compound LOD (ng/cm2) Acenaphthene 0.78 Phenanthrene 1.37 Anthracene 0.36 Fluoranthene 0.13 Pyrene 0.14 Chrysene/benzo(a)anthracene 0.18 Benzo(b,k)fluoranthene 1.74 Benzo(a)pyrene 0.02 Benzo(g,h,i)perylene 0.07 Dibenz(a,h)anthracene 0.05 Indeno(1,2,3-c,d)pyrene 0.04
There were also PAHs present in the field blank. However, all concentrations of the detected PAHs in the field blank were below LOD, see Figure 2.
Figure 2. Concentration of each compound in the field blank compared to the LOD obtained from analysing five method blanks.
Upper bound concentrations are used to present the total PAH concentrations on the dermal tapes in Figure 3. When applying upper bound concentrations, a concentration corresponding to LOD/2 is used for analytes that have concentrations below LOD. In appendix Table 5Table
0 0.5 1 1.5 2 2.5 Co nc en tra tio n ( ng/ cm 2) Fieldblank LOD
11 7, a more detailed compilation of the complete data set is presented, where both lower and upper bound concentrations are shown. When calculating lower bound concentrations all concentrations below LOD are considered to be zero.
Figure 3. Total concentration (upper bound) of US EPA priority PAHs (except of naphthalene, acenaphthylene and fluorene) in samples collected before and after a working day. Samples collected in palms before working day can be seen as blue bars, samples collected in palms after the working day is presented as orange bars and samples from necks after a working day are shown as grey bars. The black line represents the total concentration of LOD divided by two. The recovery of sample #20 was overall poor (≤ 43%), and the results should only be taken as an estimation.
Eighteen study participants were included in this study, and all were providing dermal samples from the palm before and after a working day. However, dermal samples from the neck were only collected from fourteen of the study participants. There were only a few PAHs detected on the dermal tapes, i.e. acenapthene, pyrene, phenanthrene, fluoranthene, chrysene/benzo[a]anthracene and benzo[a]pyrene. Overall, the concentrations of the detected compounds were low and close to LOD. When comparing the dermal samples from before and after a working day it can be seen that the detection frequencies of PAHs increase in the samples collected after the working day. The total PAH concentration (upper bound) in samples also increase slightly after the working day. The samples taken before the working day ranged from <2.4 to 3.8 ng/cm2 (mean 3.0 ng/cm2) in upper bound concentrations when sample #20 is
excluded due to uncertain results. The samples taken after the working day ranged from <2.4 to 5.2 ng/cm2 (mean 3.1 ng/cm2) and the samples taken from the neck after a working day had
concentrations in the following range: <2.4 to 7.1 ng/cm2 (mean 4.1 ng/cm2).
From Figure 3 it can be seen that for ten of the study participants the total concentration was higher or slightly higher in palm samples taken after the working shift. Four of the samples showed similar levels of PAHs in the samples taken before and after the working shift while
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 1 2 4 7 8 9 10 11 12 13 14 15 16 18 19 20 21 22 Co nc en tra tio n ( ng/ cm 2) Worker
Before working day After working day, palm
After working day, neck
12 four of the samples from palms showed decreased concentrations of PAHs after the working shift. The observation that four of the study participants have lower concentrations after the working day can be because they forgot that they weren’t supposed to wash their hands, perhaps after a toilet visit and did that anyway. However, the samples collected from the necks of the study participants after the working day, shows higher concentrations compared to the concentrations measured in the palms before the working day in all samples except for worker #2 and #22. This might support the theory that some of the study participants had washed their hands during the day. On the other hand, this can also point on that the neck is more exposed and not covered with protective clothing in the same extent as the hands. To summarize, from Figure 3 it can be seen that the total PAHs concentration increase during a work shift for most of the workers. However, the difference is quite small and many of the detected compounds have concentrations close to their LOD both before and after working shift, indicating that the exposure is relatively low.
The difference in upper bound total PAHs concentration in samples taken in palm after working day compared to before working day are presented in Figure 4 where focus is on what type of job assignment the workers had. Red staple indicates higher PAH concentration before working start while a green staple indicates higher PAH concentration after working day.
Figure 4. Difference in upper bound total PAH concentration of US EPA priority PAHs before and after a working day from samples taken in palm for all workers. Green staple indicates higher concentration of PAH after working day, while red staple indicates higher PAH concentration before working day. The workers been categorized into three different work assignments based on their majority work task that week that the samples were taken. *unknown work task
Although the concentrations are low, it seems as all three categories of workers (office workers, machine operators and persons collecting samples) are exposed to PAHs from the working site. Still, the two persons with the highest increase in PAH concentrations after a full working day, i.e. worker 8 and 14, are persons that work outdoors on the contaminated area during the majority of the working hours. A small difference between the office workers and the machine operators can be distinguished, that the machine operators generally had a slightly higher concentration of PAHs on their hand compared to the office workers, but overall the difference among the working groups is not so remarkable. The results for study participant #20 and #21
-6.00 -5.00 -4.00 -3.00 -2.00 -1.00 0.00 1.00 2.00 3.00 4.00 1 7 15 18 21 2 9 12 13 16 19 20 22 4 8 10 14 11
Office worker Machine operator Sample taking u.k*
Concent ra tion (ng/ cm )2
13 should be considered with caution as the recovery for two of these samples were very high. It could be interesting to compare these results with results from the urine and blood samples that also were collected from the workers to see if there is a correlation between work assignment and exposure, and also if the workers are more exposed via another route, for example via inhalation than the dermal exposure.
In Dor et al. (2000) the dermal exposure of gaswork site workers was investigated, which showed that the workers’ that had an “outdoor work” were the only category (the other two in this study were mixed categories i.e. both outdoor and office, and office category) where PAH contamination could be detected. From this, it can be expected that the soil remediation workers in this study that only worked outdoors at the sampling site, were most exposed when looking from a dermal point of view, which also was the case. Same thing can also be concluded when looking at the results from Väänänen et al. (2005) where the traffic controller that worked further away from the paving site had approximately 40 times lower concentration of PAHs detected on the exposure pads than the screedmen (which give the desired dimensions for the paving site) and paver operators (which controls the paving machine). Due to this is can be expected that soil remediation workers that work outdoors in the contaminated area are at greater risk of PAH exposure.
Even though some of the machine operators and office personal showed some possible exposure, the persons active on the site collecting samples seem to be more exposed. Probably due to that they were closest to the exposure source. Things that can have an impact on the small difference that could be seen are, routines for when gloves and other protective clothing are used, if the offices are ventilated and that the machine operators are protected by a cabin equipped with carbon filter. How passage in and out from the office and machine cabin take place. But also, how much the protective clothing covers the skin and how the worker handles and acts around the contaminated area, how often the working clothes are washed and changed, and the personal factor of hygiene routine before, but perhaps more important, after working shifts.
Concentrations of 16 US EPA PAHs in two soil samples from the contaminated area are presented in appendix Figure 1Figure 2. Phenanthrene is the compound that contributes the most to the total PAH concentration in the soils, followed by fluoranthene. A small variation in the third most abundant compound can be seen between the two samples but both fluorene and pyrene contribute in a relative large amount in both samples. The two most abundant compounds are PAHs with mid molecular weight. Since they are less volatile than low molecular weight PAHs, and less bound to particles in the soil compared to the high molecular weight PAHs, it’s expected that those contribute most to the exposure of the workers. If this is the scenario the profile from the workers would match the profile from the soil.
In Figure 5 the PAH profile from the worker with the second highest total concentration of PAH after a working day is shown (i.e. study participant #8). The most abundant compound in the worker’s profile is phenanthrene, which match the profiles in soil samples (Appendix Figure 1Figure 2). This can be seen as a represent of all the workers since in 20 of the 32 (14 from neck and 18 from palm) samples taken after the working day, phenanthrene is the most abundant compound. Fluoranthene and pyrene also have a high detection frequency among the samples taken after the working day and are also shown in the PAH profile presented in Figure 5. This also correlates with the profile present in the soil from the contaminated site. However, the sampling of the workers showed small dermal concentrations of PAHs and indicate that the PAHs are bound to the soil and that the exposure from soil is rather low when looking from a
14 dermal point of view over one day. It would be interesting to look at the dermal exposure of other parts of the body and also over a longer period than one workday and to include seasonal variations and variations from weather conditions and investigate if that can affect the degree of exposure.
Figure 5. PAH profile for worker #8 using lower bound concentrations.
In Kammer et al., (2011) samples from the back of the hand showed detectable concentrations of pyrene within a range of 2.1-6.3 ng/cm2 for chimney sweeps after a work shift. Only four of
the soil remediation workers had pyrene concentrations above LOD in the samples taken before working day (0.16-0.42 ng/cm2). After the working day, pyrene was detected in the palm
samples from 12 of the 18 workers indicating that some of the workers were exposed to pyrene during soil remediation work. However, the exposure was low (0.09-0.32 ng/cm2) when
comparing with the concentrations from before working day and the results from Kammer et al. (2011). It can be concluded that the soil remediation workers were exposed to pyrene but not in so high amounts when compared to the chimney sweeps. Väänänen et al., (2005) studied pavers exposure to PAHs and detected fluoranthene on the wrists of the pavers in concentrations ranging from 0.06 to 24 ng/cm2 (all concentrations were above LOD). The concentrations were
much higher than the concentration detected for fluoranthene in the samples taken from the soil remediation workers in this study (0.08-0.69 ng/cm2, in palm after working day). It can be said
that the exposure from the contaminated soil isn’t as near as high as the exposure from pavement, but it’s hard to directly compare the values from the road pavers’ wrists to the soil remediation workers’ palms, due to a few reasons. It may be assumed that the wrist is closer to the contaminated area as it is reasonable to assume that both pavers and persons working with soil remediation use protective gloves during work. Additionally, the road pavers might not cover their wrist with so much cloths due to the very high temperature that is required for the work which can lead to higher concentrations. Washing of hands will remove a lot of the contamination which may have occurred even though that instructions during sample day told the workers not to wash their hands. According to Wester et al., (1990) approximately 95% of the PAH (benzo(a)pyrene) is washed away after water and soap wash. When comparing the PAH exposure for different occupations (i.e. chimney sweepers, road pavers and soil remediation workers) it seems as the soil remediation workers’ exposure is low.
0.00 0.50 1.00 1.50 2.00 2.50 Concent ra tion (ng/ cm 2)
15
4. Conclusions
The recently developed method for tape-stripping samples analyzed on GC-MS showed poor recovery when skin matrix was present in the samples. The ambition to use larger elution volumes during the clean-up using Florisil SPE columns did not improve the poor recoveries. However, clean-up using deactivated silica (10%) gave good recoveries for almost all 16 PAHs, with exception for the low molecular weight PAHs. For the clean-up on silica two different extraction solvents, acetonitrile and n-hexane:dichloromethane (9:1), and two different elution solvents, n-hexane and n-hexane:dichloromethane plus dichloromethane, were tested to evaluate the silica as a clean-up method. The n-hexane:dichloromethane extraction resulted in very viscous samples that couldn’t be transferred to a GC-vial. Therefore, acetonitrile was the best choice of extraction solvent. The two different elution solvents that were tested, n-hexane and n-hexane:dichloromethane plus dichloromethane, showed no difference in recovery and were both suitable for eluting PAHs from deactivated silica. However, the n-hexane: dichloromethane plus dichloromethane enable analysis of oxy-PAHs which was the reason to why these solvents were chosen.
Dermal exposure of 16 US EPA PAHs among soil remediation workers was measured and a limited number of PAHs were detected above LOD. These PAHs were acenaphthene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene/benzo(a)anthracene and benzo(a)pyrene. Although it could be concluded that workers that were in direct contact with the contaminated area (i.e. persons collecting samples) had in general higher concentration of PAHs after the working day than the other workers that worked as machine operators or at the office. In comparison with other PAHs exposed working groups such as chimney sweeps and road pavers, the total PAH exposure of the soil remediation workers was low, and concentrations ranged from <2.4 ng/cm2 to 7.1 ng/cm2 (after working day in samples taken in
neck). More research is needed to determine how the contributions from the air respectively the soil influence the dermal exposure. Although, it seems as soil remediation workers are not highly exposed according to the results from this study, which showed low dermal concentrations after a working day even though the concentrations of PAHs in the soil in some areas were very high.
16
References
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18
Appendix
Table 1. Recovery from using Florisil column for samples eluted with 12 ml hexane.
Recovery Blank #1 Blank #2 Palm #2 Forearm #2 Forearm #3 Neck #3 Ankle #2 Ankle #3 Naphthalene-D8 7.8 2.8 2.1 2.2 1.2 1 3.7 6.6 Acenaphthylene-D8 32 24 33 26 23 37 30 41 Acenaphthene-D10 29 22 27 21 19 29 25 33 Fluorene-D10 71 57 83 72 64 98 76 88 Phenanthrene-D10 53 43 62 59 56 77 66 71 Anthracene-D10 36 29 43 40 39 57 45 49 Fluoranthene-D10 44 39 44 50 45 55 53 54 Pyrene-D10 47 39 48 48 47 62 55 56 Benzo[a]anthracene-D12 70 59 72 66 62 81 73 79 Chrysene-D12 54 41 50 41 40 49 47 47 Benzo[b]fluoranthene-D12 59 23 34 22 23 24 49 73 Benzo[k]fluoranthene-D12 51 18 25 17 18 10 22 29 Benzo[a]pyrene-D12 34 14 17 6.3 5.8 0 20 59 Benzo[g,h,i]perylene-D12 6.7 0 0 0 0 0 0 40 Indeno[1,2,3-c,d]pyrene-D12 9.9 0 0 0 0.5 0 0 43 Dibenz[a,h]anthracene-D14 0 0 0 0 0 0 0 27
Table 2. Concentration of each compound in the five method blanks. The concentration of benzo(g,h,i)perylene and indeno(1,2,3-c,d)pyrene is calculated as 3 times signal to noise.
Compound Blank #1 (ng/cm2) Blank #2 (ng/cm2) Blank #3 (ng/cm2) Blank #4 (ng/cm2) Blank #5 (ng/cm2) Naphthalene 2.31 2.90 3.93 1.83 8.14 Acenaphthylene 0.15 0.11 0.11 0.10 0.12 Acenaphthene 0.63 0.57 0.60 0.55 0.69 Phenanthrene 1.01 0.93 0.81 1.15 1.04 Anthracene 0.23 0.21 0.13 0.07 0.07 Fluoranthene 0.10 0.09 0.08 0.11 0.08 Pyrene 0.11 0.11 0.10 0.13 0.11 Chrysene/benzo[a]anthracene 0.09 0.11 0.13 0.13 0.14 Benzo[b,k]fluoranthene 1.41 1.46 1.42 1.33 1.60 Benzo[a]pyrene 0.01 0.01 0 0.01 0 Benzo[g,h,i]perylene 0.02 0.04 0.03 0.03 0.05 Dibenz[a,h]anthracene 0.03 0.03 0.01 0 0.01 Indeno[1,2,3-cd]pyrene 0.01 0.02 0.03 0.02 0.03
19
Table 3. Selected samples from the soil remediation workers with moderate or poor recovery of the deuterium labelled standards.
Recovery 7 EM HF 20 FM HF 20 EM HF 21 FM HF 21 Hals
Naphthalene-D8 4.8 2.2 43 21 6.5
Acenaphthylene-D8 NA* NA* NA* NA* NA*
Acenaphthene-D10 19 7.6 110 95 24 Fluorene-D10 40 31 129 115 45 Phenanthrene-D10 35 8.3 119 119 35 Anthracene-D10 39 11 145 148 45 Fluoranthene-D10 46 7.7 148 154 42 Pyrene-D10 46 11 148 162 44 Benzo(a)anthracene-D12 61 43 162 131 48 Chrysene-D12 52 13 175 164 44 Benzo(b)fluoranthene-D12 54 22 108 110 36 Benzo(k)fluoranthene-D12 46 4.1 151 150 47 Benzo(a)pyrene-D12 44 9.9 154 156 46 Benzo(g,h,i)perylene-D12 56 13 175 161 53
Indeno(1,2,3-c,d)pyrene-D12 NA* NA* NA* NA* NA*
Dibenz(a,h)anthracene-D14 52 11 177 163 52
Naphthalene-D8 104 93 99 68 84
* not analysed because included in wrong SIM time window.
Table 4. Lowest and highest values of recovery of deuterium labelled standards in samples from soil remediation workers.
Recovery Min Max
Max when #20 from palm after work and #21 before
work are excluded
Naphthalene-D8 0.5 43 29
Acenaphthylene-D8 NA* NA* NA*
Acenaphthene-D10 19 110 70 Fluorene-D10 40 129 113 Phenanthrene-D10 35 119 93 Anthracene-D10 39 148 108 Fluoranthene-D10 42 154 118 Pyrene-D10 44 162 114 Benzo(a)anthracene-D12 48 162 109 Chrysene-D12 44 175 119 Benzo(b)fluoranthene-D12 36 110 107 Benzo(k)fluoranthene-D12 46 151 117 Benzo(a)pyrene-D12 44 156 108 Benzo(g,h,i)perylene-D12 53 175 124
Indeno(1,2,3-c,d)pyrene-D12 NA* NA* NA*
Dibenz(a,h)anthracene-D14 52 177 119
20
Table 5 Concentration in ng/cm2 of each compound in samples before working day, LOD and LOD/2. Digits highlighted in red indicates values below LOD and the given concentration corresponds
to LOD/2. Total PAH concentration lower bound is calculated on all concentrations >LOD. In upper bound, values below LOD are set to LOD/2 for the calculation of the total PAHs concentration.
Worker Compound 1 2 4 7 8 9 10 11 12 13 14 15 16 18 19 20 21 22 Conc. of LOD (ng/cm2) Conc. of LOD/2 (ng/cm2) Acenaphthene 1.21 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 0.90 0.78 0.39 Phenanthrene <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 4.97 1.69 <0.68 1.37 0.68 Anthracene <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 1.05 <0.18 <0.18 0.36 0.18 Fluoranthene <0.06 <0.06 0.65 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 1.11 0.26 0.19 0.13 0.06 Pyrene 0.16 <0.07 0.42 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 0.19 0.16 0.14 0.07 Chrysene/benzo[a]anthracene <0.09 <0.09 0.27 <0.09 <0.09 <0.09 <0.09 <0.09 <0.09 <0.09 <0.09 <0.09 <0.09 <0.09 <0.09 <0.09 <0.09 0.23 0.18 0.09 Benzo[b,k]fluoranthene <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 1.74 0.87 Benzo[a]pyrene <0.01 <0.01 0.02 0.03 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.03 <0.01 <0.01 0.01 0.01 Benzo[g,h,i]perylene <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 0.07 0.03 Dibenz[a,h]anthracene <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 0.05 0.03 Indeno[1,2,3-c,d]pyrene <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 0.04 0.02 Total PAH conc. (lower
bound) 1.37 0 1.35 0.03 0 0 0 0 0 0 0 0 0 0 0 7.15 2.14 1.47
Total PAH conc. (upper
21
Table 6. Concentration of PAH (ng/cm2) from samples taken at the palm after working day. Red value indicates concentration below LOD and the given concentration corresponds to LOD/2.
Worker Compound 1 2 4 7 8 9 10 11 12 13 14 15 16 18 19 20 21 22 Conc. of LOD (ng/cm2) Conc. of LOD/2 (ng/cm2) Acenaphthene <0.39 <0.39 <0.39 0.88 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 1.30 <0.39 <0.39 <0.39 <0.39 <0.39 <0.39 0.99 0.78 0.39 Phenanthrene <0.68 <0.68 <0.68 1.42 2.33 <0.68 <0.68 <0.68 <0.68 <0.68 1.80 <0.68 <0.68 <0.68 <0.68 <0.68 <0.68 1.52 1.37 0.68 Anthracene <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 0.36 0.18 Fluoranthene <0.06 0.18 0.54 0.34 0.69 0.45 <0.06 0.17 0.15 <0.06 0.49 <0.06 0.25 <0.06 0.48 0.59 0.17 0.33 0.13 0.06 Pyrene <0.07 0.14 0.32 0.25 0.29 0.31 <0.07 0.14 <0.07 <0.07 0.24 <0.07 0.19 <0.07 0.28 0.32 0.15 0.19 0.14 0.07 Chrysene/benzo[a]anthracen e <0.09 <0.09 0.24 0.18 0.24 0.31 <0.09 <0.09 <0.09 <0.09 0.19 <0.09 0.20 <0.09 0.22 0.27 <0.09 0.22 0.18 0.09 Benzo[b,k]fluoranthene <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 1.74 0.87 Benzo[a]pyrene <0.01 <0.01 <0.01 0.01 0.01 0.02 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.01 0.01 Benzo[g,h,i]perylene <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 0.07 0.03 Dibenz[a,h]anthracene <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 0.05 0.03 Indeno[1,2,3-c,d]pyrene <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 0.04 0.02
Total PAH conc. (lower bound)
0 0.32 1.10 3.07 3.55 1.09 0 0.31 0.15 0 4.02 0 0.64 0 0.98 1.19 0.32 3.25
Total PAH conc. (upper bound)
22
Table 7 Concentrations in samples taken in neck after working day for each compound in ng/cm2. Values lower than LOD are indicated in red and the given concentration corresponds to LOD/2.
Worker Compound 2 4 8 9 11 12 13 14 16 18 19 20 21 22 Conc. Of LOD (ng/cm2) Conc. Of LOD/2 (ng/cm2) Acenaphthene <0.39 0.79 0.84 <0.39 1.13 <0.39 <0.39 1.09 0.98 1.40 <0.39 <0.39 <0.39 <0.39 0.78 0.39 Phenanthrene <0.68 2.70 1.81 <0.68 1.90 <0.68 <0.68 2.09 1.61 2.55 <0.68 1.70 1.97 <0.68 1.37 0.68 Anthracene <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 <0.18 0.36 0.18 Fluoranthene <0.06 1.31 <0.06 0.29 0.38 0.23 <0.06 0.31 0.21 0.28 0.19 0.23 0.37 0.27 0.13 0.06 Pyrene <0.07 0.65 0.23 0.20 0.25 0.16 <0.07 0.16 0.16 0.19 0.15 0.17 0.22 0.19 0.14 0.07 Chrysene/benzo[a]anthracene <0.09 0.53 0.19 0.19 0.18 <0.09 <0.09 <0.09 <0.09 <0.09 <0.09 0.18 0.21 0.21 0.18 0.09 Benzo[b,k]fluoranthene <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 <0.87 1.74 0.87 Benzo[a]pyrene 0.01 0.02 <0.01 <0.01 0.01 <0.01 <0.01 0.01 0.01 <0.01 <0.01 <0.01 0.01 0.01 0.01 0.01 Benzo[g,h,i]perylene <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 0.07 0.03 Dibenz[a,h]anthracene <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 0.05 0.03 Indeno[1,2,3-c,d]pyrene <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 0.04 0.02
Total PAH conc. (lower
bound) 0.01 5.99 3.07 0.67 3.85 0.39 0 3.65 2.97 4.43 0.34 2.27 2.77 0.67
Total PAH conc. (upper
23
Figure 1 Total concentrations of 16 US EPA PAHs in a soil sample from the creosote contaminated area in µg/kg dm soil.
Figure 2 Another soil sample from the creosote contaminated area showing total concentrations of 16 US EPA PAHs in ug/kg dm soil.
0 50000 100000 150000 200000 250000 300000 350000 400000 Concent ra tion µg /k g 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 Concent ra tion µg /k g
