Determination of resin acids during production of wood pellets--a comparison of HPLC/ESI-MS with the GC/FID MDHS 83/2 method

Resin acids are constituents of natural and technical products of widespread use. Exposure is known to cause health effects in the airways and on the skin. Liquid chromatography/positive ion electrospray-mass spectrometry (HPLC/pos ESI-MS) was investigated for determination of 7-oxodehydroabietic (7-OXO), dehydroabietic (DHAA) and abietic acid (AA) in wood dust-containing air samples as a derivatisation-free alternative to the GC/FID HSE method 83/2, developed by the Health and Safety Executive UK. The resin acid 7-OXO was measured as a marker for oxidised resin acids, which are known to be the main contact allergens in colophonium. The found detection limits were 0.42 ng m(-3) for 7-OXO, 5.2 ng m(-3) for DHAA and 9.4 ng m(-3) for AA, respectively, which are considerably lower than with the GC/FID method (24, 115 and 89 ng m(-3)). The two methods correlated well, although consistently and significantly lower concentrations of 7-OXO were detected with LC/MS. The higher concentration of this compound with MDHS 83/2 is suggested to be an artefact from the derivatisation step in the presence of soluble wood dust remains.     

Evaluation of a tape-stripping technique for measuring dermal exposure to pyrene and benzo(a)pyrene

Epidemiological studies have shown an increased incidence of cancer among workers occupationally exposed to polycyclic aromatic hydrocarbons (PAHs). As the dermal route is considered important for exposure to PAHs in the workplace, the aim of this study was to develop and evaluate a tape-stripping technique for monitoring dermal exposure to pyrene and benzo(a)pyrene. The tape-stripping method was evaluated by applying different concentrations of pyrene and benzo(a)pyrene directly onto tape strips (spiked tapes), clean glass plates, and on the skin of five volunteers. The glass plates were stripped using a single strip of tape and the skin of the volunteers was stripped with five consecutive strips of tape after 0 and 30 minutes. The method was also tested on five chimney sweeps at three exposure sites. High-performance liquid chromatography with fluorescence detection was employed for the quantification of pyrene and benzo(a)pyrene. The mean recovery from the spiked tapes was 97% for pyrene and 93% for benzo(a)pyrene. The mean overall recovery from the glass plates was 88% and 76% for pyrene and 88 and 85% for benzo(a)pyrene. The recovery from human skin was 70% and 63% for pyrene and 60 and 54% for benzo(a)pyrene, after 0 and 30 minutes, respectively. A concentration gradient was clearly detected between the five consecutive strips. Detectable amounts of pyrene and benzo(a)pyrene were found on all chimney sweeps at all exposure sites. This method can thus be used to detect and quantify dermal exposure to pyrene and benzo(a)pyrene. The results also show that pyrene and benzo(a)pyrene may be taken up by the skin.     

A method for measuring dermal exposure to multifunctional acrylates

UV-curable acrylates are used increasingly for coating wood surfaces in the furniture industry. One of the active components, tripropylene glycol diacrylate (TPGDA), is known to be both an allergen and irritant to the skin. Methods to measure dermal exposure to skin irritants and allergens, such as acrylates, are insufficient for exposure assessment and there is none for this compound. The aim of this investigation was to develop a skin and surface sampling method, based on tape stripping, and a gas chromatographic method for quantitative analysis for assessing occupational skin exposure to multifunctional acrylates. Twelve adhesives were tested for their efficiency to remove TPGDA and UV-coating from a glass surface, the skin of guinea pigs and human volunteers employing the tape-stripping method in order to find the best performing tape. Variables that affect removal efficiency such as the applied dose and its retention time on the skin, tape adhesion time on the skin, and the number of strippings required to detect the contaminant from the skin were studied. Fixomull tape performed the best during sampling and analysis and had the most consistent removal efficiencies for the studied substances. The average removal efficiency with a single stripping at the 2 microliters TPGDA exposed skin sites was 85% (RSD = 14.1), and for UV-resin exposed sites 63% (RSD = 20.2). The results indicated that this method can be used for measuring dermal exposure to multifunctional acrylates efficiently, accurately, and economically. This method provides a sensitive and powerful tool for the assessment of dermal exposure to multifunctional acrylates both from the skin and from other contaminated surfaces in occupational field settings.     

Development and application of quantitative methods for monitoring dermal and inhalation exposure to propiconazole

Quantitative methods to measure dermal and inhalation exposure to the fungicide propiconazole were developed in the laboratory and applied in the occupational exposure setting for monitoring five farm workers' exposure during pesticide preparation and application to peach crops. Dermal exposure was measured with tape-strips applied to the skin, and the amount of propiconazole was normalized to keratin content in the tape-strip. Inhalation exposure was measured with an OVS tube placed in the worker's breathing-zone during pesticide handling. Samples were analyzed by GC-MS in EI+ mode (limit of detection 6 pg microl(-1)). Dermal exposure ranged from non-detectable to 32.1 +/- 22.6 ng per microg keratin while breathing-zone concentrations varied from 0.2 to 2.2 microg m(-3). A positive correlation was observed between breathing-zone concentrations and ambient air temperature (r2 = 0.87, p < 0.01). Breathing-zone concentrations did not correlate with dermal exposure levels (r2 = 0.11, p = 0.52). Propiconazole levels were below limit of detection when rubber gloves, coveralls, and full-face mask were used. The total-body propiconazole dose, determined for each worker by summing the estimated dermal dose and inhalation dose, ranged from 0.01 to 12 microg per kg body weight per day. Our results show that tape-stripping of the skin and the OVS can be effectively utilized to measure dermal and inhalation exposure to propiconazole, respectively, and that the dermal route of exposure contributed substantially more to the total dose than the inhalation route.     

Quantitative monitoring of dermal and inhalation exposure to 1,6-hexamethylene diisocyanate monomer and oligomers

Respiratory sensitization and occupational asthma are associated with exposure to 1,6-hexamethylene diisocyanate (HDI) in both monomeric and oligomeric forms. The monomer and polymers of diisocyanates differ significantly in their rates of absorption into tissue and their toxicity, and hence may differ in their contribution to sensitization. We have developed and evaluated a liquid chromatography/mass spectrometry (LC-MS) method capable of quantifying HDI and its oligomers (uretidone, biuret, and isocyanurate) in air, tape-stripped skin, and paint samples collected in the automotive refinishing industry. To generate analytical standards, urea derivatives of HDI, biuret, and isocyanurate were synthesized by reaction with 1-(2-methoxyphenyl)piperazine and purified. The urea derivatives were shown to degrade on average by less than 2% per week at -20 degrees C over a 2 month period in occupational samples. The average recovery of HDI and its oligomers from tape was 100% and the limits of detection were 2 and 8 fmol microl(-1), respectively. Exposure assessments were performed on 13 automotive spray painters to evaluate the LC-MS method and the sampling methods under field conditions. Isocyanurate was the most abundant component measured in paint tasks, with median air and skin concentrations of 2.4 mg m(-3) and 4.6 microg mm(-3), respectively. Log-transformed concentrations of HDI (r = 0.79, p < 0.0001) and of isocyanurate (r = 0.71, p < 0.0001) in the skin of workers were correlated with the log-transformed product of air concentration and painting time. The other polyisocyanates were detected on skin for less than 25% of the paint tasks. This LC-MS method provides a valuable tool to investigate inhalation and dermal exposures to specific polyisocyanates and to explore relative differences in the exposure pathways.     

Dermal exposure to monoterpenes during wood work

The dermal exposure to the suspected allergenic monoterpenes [small alpha]-pinene, [small beta]-pinene and [capital Delta](3)-carene was assessed with a patch sampling technique. The patch used was made of activated charcoal sandwiched between two layers of cotton cloth. Patches were fastened at 12 different spots on a sampling overall and at the front of a cap to estimate the potential exposure of the body. Fastening two patches on a cotton glove, one patch representing the dorsal side and one patch representing the palm of the hand respectively, assessed the exposure on the hands. Sampling was carried out during collecting of pine and spruce boards in sawmills and during sawing of pine wood pieces in joinery shops respectively. The potential dermal exposure of the total body was 29.0-1 890 mg h(-1) with a geometric mean (GM) of 238 mg h(-1) during sawing. During collecting the GM was estimated to 100 mg h(-1) with a range of 12.2-959 mg h(-1). The hands had a mean exposure of 9.24 mg h(-1) during sawing and 3.25 mg h(-1) during collecting respectively. The good correlation between the mass of contamination on the individual body parts and the potential body exposure indicates that sampling can be performed on one body part to give a good estimation of the potential body exposure. Monoterpenes were detected at patches fastened underneath the protective clothing indicating a contamination of the skin of the worker. The patch used may overestimate the dermal exposure.     

An FTIR investigation of isocyanate skin absorption using in vitro guinea pig skin

Isocyanates may cause contact dermatitis, sensitization and asthma. Dermal exposure to aliphatic and aromatic isocyanates can occur in various exposure settings. The fate of isocyanates on skin is an important unanswered question. Do they react and bind to the outer layer of skin or do they penetrate through the epidermis as unreacted compounds? Knowing the kinetics of these processes is important in developing dermal exposure sampling or decontamination strategies, as well as understanding potential health implications such exposure may have. In this paper the residence time of model isocyanates on hairless guinea pig skin was investigated in vitro using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometry. Model isocyanates tested were octyl isocyanate, polymeric hexamethylene diisocyanate isocyanurate (pHDI), polymeric isophorone diisocyanate isocyanurate (pIPDI) and methylenediphenyl diisocyanate (MDI). Isocyanates in ethyl acetate (30 microL) were spiked directly on the skin to give 0.2-1.8 micromol NCO cm(-2) (NCO = -N=C=O), and absorbance of the isocyanate group and other chemical groups of the molecule were monitored over time. The ATR-FTIR findings showed that polymeric isocyanates pHDI and pIPDI may remain on the skin as unreacted species for many hours, with only 15-20% of the total isocyanate group disappearing in one hour, while smaller compounds octyl isocyanate and MDI rapidly disappear from the skin surface (80+% in 30 min). Isocyanates most likely leave the skin surface by diffusion predominantly, with minimal reaction with surface proteins. The significance of these findings and their implications for dermal exposure sampling and isocyanate skin decontamination are discussed.     

Assessment of dermal exposure to benzene and toluene in shoe manufacturing by activated carbon cloth patches

OBJECTIVES: The aim of this investigation was to use activated carbon cloth (ACC) patches to study the probability and extent of dermal exposure to benzene and toluene in a shoe factory. METHODS: Inhalation and dermal exposure loading were measured simultaneously in 70 subjects on multiple days resulting in 113 observations. Dermal exposure loading was assessed by ACC patches attached to likely exposed skin areas (e.g. the palm of the hand and abdomen). A control patch at the chest and an organic vapor monitor (OVM) were used to adjust the hand and abdomen patches for the contribution from the air through passive absorption of benzene and toluene on the ACC patches. Systemic exposure was assessed by quantification of unmetabolized benzene (UBz) and toluene (UTol) in urine. RESULTS: Mean air concentrations for the study population were 1.5 and 7.5 ppm for benzene and toluene, respectively. Iterative regression analyses between the control patch, OVM and the dermal patches showed that only a small proportion of the ACC patches at the hand had likely benzene (n = 4; mean 133 microg cm(-2) h(-1)) or toluene (n = 5; mean 256 microg cm(-2) h(-1)) contamination. Positive patches were exclusively observed among subjects performing the task of gluing. Significant dermal exposure loading to the abdomen was detected only for toluene (n = 2; mean 235 microg cm(-2) h(-1)). No relation was found between having a positive hand or abdomen ACC patch and UBz or UTol levels. In contrast a strong association was found between air levels of benzene (p = 0.0016) and toluene (p < 0.0001) and their respective urinary levels. CONCLUSIONS: ACC patches are shown to be a useful technique for quantifying the probability of dermal exposure to organic solvents and to provide estimates of the potential contribution of the dermal pathway to systemic exposure. Using ACC patches we show that dermal exposure to benzene and toluene in a shoe manufacturing factory is probably rare, and when it occurred exposures were relatively low and did not significantly contribute to systemic exposure.     

Penetration patterns of monomeric and polymeric 1,6-hexamethylene diisocyanate monomer in human skin

We investigated penetration patterns of monomeric and polymeric 1,6-hexamethylene diisocyanate (HDI), experimentally and as part of commercial products, in excised full-thickness human skin at 5, 10, 30, or 60 min after exposure. We observed that both monomeric and polymeric HDI were readily absorbed into the skin and that the clearcoat composition affects the penetration rate of the individual isocyanates. The short-term absorption rates for HDI monomer, biuret, and isocyanurate were determined and used to estimate the exposure time required to reach a body burden equal to the American Conference of Governmental Industrial Hygienists (ACGIH) inhalation threshold limit value (TLV) or Oregon State occupational exposure limit (OEL). Oregon is the only government entity in the United States to promulgate a short-term exposure limit (STEL) for HDI-based polyisocyanates biuret and isocyanurate. Based on these absorption rates for a slow-drying clearcoat after 10 min (1.33 μg cm(-2) h(-1)) or 60 min (0.219 μg cm(-2) h(-1)), we calculated that 6.5 and 40 min dermal exposure, respectively, is required to achieve a dose of HDI equivalent to the ACGIH TLV. For biuret, the time to achieve a dose equivalent to the Oregon OEL for slow-drying clearcoat was much shorter (<31 min) than that for fast-drying clearcoat (618 min). Isocyanurate had the shortest skin absorption times regardless of clearcoat formulation (14 s-1.7 min). These results indicate that the dose received through dermal exposure to HDI-containing clearcoats has a significant potential to exceed the dose equivalent to that received through inhalation exposure at established regulatory limits. A critical need exists to monitor dermal exposure quantitatively in exposed workers, to use proper protective equipment to reduce dermal exposure, and to re-evaluate regulatory exposure limits for isocyanates.     

Hygienic guidance values for wipe sampling of antineoplastic drugs in Swedish hospitals

The use of antineoplastic drugs in health care steadily increases. Health care workers can be occupationally exposed to antineoplastic drugs classified as carcinogenic or teratogenic. Monitoring of surface contamination is a common way to assess occupational exposure to antineoplastic drugs, since wipe sampling is used as a surrogate measure of dermal exposure. Since no occupational limits for antineoplastic drugs in work environments exist, 'hygienic guidance values' (HGVs) should be used instead. HGVs are practicable, achievable levels, not health based, and can be calculated from exposure data from representative workplaces with good occupational hygiene practices. So far, guidance values for surface monitoring of antineoplastic drugs only exist for pharmacies where antineoplastic drugs are prepared. The objective was to propose HGVs for surface monitoring of cyclophosphamide (CP) and ifosfamide (IF) in Swedish hospitals where antineoplastic drugs are administered to patients. In total, 17 workplaces located at six hospitals in Sweden were surveyed by wipe sampling. Wipe samples were collected, worked up and then analyzed with liquid chromatography tandem mass spectrometry. Surface contamination of CP and IF was found on 80% and 73% of the sampled surfaces, thus indicating that there is potential for health care workers to be exposed to CP and IF via the skin. The median surface load of CP was 3.3 pg cm(-2) (range <0.05-10,800 pg cm(-2)). The corresponding value for IF was 4.2 pg cm(-2) (range <0.13-95,000 pg cm(-2)). The highest surface loads were found on the floors. The proposed HGVs were set at 90th percentile values, and can be applicable to hospital workplaces where patients are treated with CP or IF. Surface monitoring combined with HGVs is a useful tool for health care workers to regularly benchmark their own surface loads which could control and reduce the occupational exposure to CP and IF in hospital workplaces. Thus, the occupational safety of the health care workers will be increased.     

Occurrence of disinfection by-products in tap water distribution systems and their associated health risk

The concentrations of trihalomethanes (THMs), including chloroform, bromodichloromethane, dibromochloromethane, and bromoform, and haloacetic acids (HAAs; monochloroacetic acid, monobromoacetic acid, dibromoacetic acid, dichloroacetic acid, and trichloroacetic acid) were measured in tap waters passing through water distribution systems of six water treatment plants in Seoul, Korea, and their associated health risks from exposure to THMs through ingestion, dermal contact, and inhalation were estimated using a probabilistic approach. The concentration ranges for total THMs and HAA₅ were 3.9–53.5 and <LOD–49.5 μg/L, respectively. Among DBPs, chloroform, bromodichloromethane, dichloroacetic acid, and trichloroacetic acid were the most frequently detected. Spatial and seasonal variations in concentrations of THMs and HAAs in the six water distribution systems were significant (P?<?0.001).The mean lifetime cancer risks through ingestion, dermal contact, and inhalation during showering ranged as 7.23–10.06?×?10^?6, 2.19–3.63?×?10^?6, and 5.22–7.35?×?10^?5, respectively. The major exposure route to THMs was inhalation during showering. Sensitivity analysis showed that shower time and shower frequency had a great impact on the lifetime cancer risk by the exposure to THMs in tap water.     

Dermal Insecticide Residues from Birds Inhabiting an Orchard

The US Environmental Protection Agency conducts risk assessments of insecticide applications to wild birds using a model that is limited to the dietary route of exposure. However, free-flying birds are also exposed to insecticides via the inhalation and dermal routes. We measured azinphos-methyl residues on the skin plus feathers and the feet of brown-headed cowbirds (Molothrus ater) in order to quantify dermal exposure to songbirds that entered and inhabited an apple (Malus x domestica) orchard following an insecticide application. Exposure to azinphos-methyl was measured by sampling birds from an aviary that was built around an apple tree. Birds sampled at 36 h and 7-day post-application were placed in the aviary within 1 h after the application whereas birds exposed for 3 days were released into the aviary 4-day post-application. Residues on vegetation and soil were also measured. Azinphos-methyl residues were detected from the skin plus feathers and the feet from all exposure periods. Our results underscore the importance of incorporating dermal exposure into avian pesticide risk assessments.     

Addressing analytical uncertainties in the determination of trichloroacetic acid in soil

Soil is an important compartment in the environmental cycling of trichloroacetic acid (TCA), but soil TCA concentration is a methodologically defined quantity; analytical methods either quantify TCA in an aqueous extract of the soil, or thermally decarboxylate TCA to chloroform in the whole soil sample. The former may underestimate the total soil TCA, whereas the latter may overestimate TCA if other soil components (e.g. humic material) liberate chloroform under the decarboxylation conditions. The aim of this work was to show that extraction and decarboxylation methods yield different TCA concentrations because the decarboxylation method can also determine "bound" TCA. Experiments with commercial humic acid solutions showed there was no additional chloroform formation under decarboxylation conditions, and that all TCA in a TCA-humic acid mixture could be quantitatively determined (108 +/- 13%). Anion exchange resin was used as a provider of solid-phase TCA binding; only 5 +/- 1% of a TCA solution mixed with the resin was present in the aqueous extract subsequently separated from the resin, yet the decarboxylation method yielded mass balance (123 +/- 22%) with TCA remaining in the resin. In aqueous extraction of a range of soil samples (with or without added TCA spike), the decarboxylation method was able to satisfactorily account for TCA in the extractant + residue post-extraction, compared with whole-soil TCA (+ spike) pre-extraction: e.g. mass balances for unspiked soil from Sikta spruce and larch forest were 99 +/- 8% and 93 +/- 6%, respectively, and for TCA-spiked forest and agricultural soils were 114 +/- 13% and 102 +/- 2%. In each case recovery of TCA in the extractant was substantially less than 100%(<20% for unspiked soils, <55% for spiked soils). Extraction efficiencies were generally lower in more organic soils. The results suggest that analytical methods which utilise aqueous extraction may underestimate whole-soil TCA concentrations. Application of both methodologies together may enhance insight into TCA behaviour in soil.     

Iodide-assisted total lead measurement and determination of different lead fractions in drinking water samples

Lead and its compounds are toxic and can harm human health, especially the intelligence development in children. Accurate measurement of total lead present in drinking water is crucial in determining the extent of lead contamination and human exposure due to drinking water consumption. The USEPA method for total lead measurement (no. 200.8) is often used to analyze lead levels in drinking water. However, in the presence of high concentration of the tetravalent lead corrosion product PbO(2), the USEPA method was not able to fully recover particulate lead due to incomplete dissolution of PbO(2) particles during strong acid digestion. In this study, a new procedure that integrates membrane separation, iodometric PbO(2) measurement, strong acid digestion and ICP-MS measurement was proposed and evaluated for accurate total lead measurement and quantification of different lead fractions including soluble Pb(2+), particulate Pb(II) carbonate and PbO(2) in drinking water samples. The proposed procedure was evaluated using drinking water reconstituted with spiked Pb(2+), spiked particulate Pb(II) carbonate and in situ formed or spiked PbO(2). Recovery tests showed that the proposed procedure and the USEPA method can achieve 93-112% and 86-103% recoveries respectively for samples containing low PbO(2) concentrations (0.018-0.076 mg Pb per L). For samples containing higher concentrations of PbO(2) (0.089-1.316 mg Pb per L), the USEPA method failed to meet the recovery requirement for total lead (85-115%) while the proposed method can achieve satisfactory recoveries (91-111%) and differentiate the soluble Pb(2+), particulate Pb(II) carbonate and PbO(2).     

A method for measuring the potential dermal exposure to methyl methacrylate during two different dental technical work tasks

Dental technicians are exposed on a daily basis to undiluted methyl methacrylate (MMA) when performing various routine tasks. Although the clinical effects of this chemical have been known for decades, no previous studies have been performed to estimate the potential dermal exposure to it. In this study we describe a patch-sampling technique to intercept the MMA that would otherwise have contaminated the skin on different parts of the hand and lower arm. Two different work tasks, making an orthodontic splint and denture preparation, were both performed under simulated workplace conditions twice by two recent graduated dental technicians. Air measurements were collected simultaneously. The results indicate that the exposure patterns associated with producing an orthodontic splint and denture preparation differed. We found work task-dependent differences in the amounts of MMA collected at the different parts of each hand, and differences between the right and left hands. There was also an interaction between hand and work task, especially for the right hand. The air measurements were positively correlated with the dermal exposure. This study highlights the importance of using a measurement strategy that takes the variability within the hand/arm body parts into account when measuring potential exposure during these kinds of work tasks. In order to establish future dermal exposure limits, more workplace and experimental studies are required.     

Road pavers' occupational exposure to asphalt containing waste plastic and tall oil pitch

Waste plastic (WP) and tall oil pitch (T), which are organic recycled industrial by-products, have been used as a binder with bitumen in stone mastic asphalt (SMA) and asphalt concrete (AC). We compared the exposure over one workday in 16 road pavers participating in a survey at four paving sites, using mixes of conventional asphalt (SMA, AC) or mixes containing waste material (SMA-WPT, AC-WPT). The concentrations of 11 aldehydes in air were 515 and 902 microg m(-3) at the SMA-WPT and AC-WPT worksites, being 3 and 13 times greater than at the corresponding worksites laying conventional asphalt. Resin acids (2-42 microg m(-3)), which are known sensitizers, were detected only during laying of AC-WPT. The emission levels (microg m(-3)) of total particulates (300-500), bitumen fumes (60-160), bitumen vapour (80-1120), naphthalene (0.59-1.2), phenanthrene (0.21-0.32), pyrene (<0.015-0.20), benzo(a)pyrene (<0.01) and the sum of 16 PAHs (polycyclic aromatic hydrocarbons, 1.28-2.00) were similar for conventional and WPT asphalts. The dermal deposition of 16 PAHs on exposure pads (on workers' wrist) was low in all pavers (0.7-3.5 ng cm(-2)). Eight OH-PAH biomarkers of naphthalene, phenanthrene and pyrene exposures were quantified in pre- and post-shift urine specimens. The post-shift concentrations (mean +/- SD, micromol mol(-1) creatinine) of 1- plus 2-naphthol; 1-,2-,3-,4- plus 9-phenanthrol; and 1-hydroxypyrene were, respectively, for asphalt workers: 18.1+/- 8.0, 2.41 +/- 0.71 and 0.66+/- 0.58 (smokers); 6.0+/- 2.3, 1.70+/- 0.72 and 0.27+/- 0.15 (non-smokers); WPT asphalt workers: 22.0+/- 9.2, 2.82+/- 1.11 and 0.76+/- 0.18 (smokers); 6.8+/- 2.6, 2.35+/- 0.69 and 0.46+/- 0.13 (non-smokers). The work-related uptake of PAHs was low in all pavers, although it was significantly greater in smokers than in non-smokers. The WPT asphalt workers complained of eye irritation and sore throat more than the pavers who had a much lower exposure to aldehydes and resin acids.     

Uptake and bioavailability of persistent organic pollutants by plants grown in contaminated soil

This paper assesses the uptake of persistent organic pollutants (POP's) into plants. In particular, uptake of alpha-endosulfan, beta-endosulfan and endosulfan sulfate from lettuce. The lettuce plants were grown on compost that had previously been contaminated at 10 and 50 microg g(-1) per POP. The soil was slurry spiked by adding the appropriate amount of POP in acetone in an approximate ratio of 1 ratio 2, w/v soil ratio solvent. The solvent was left to evaporate at ambient temperature for 24 hours. Lettuce plants were grown under artificial daylight for 12 hours a day. The influence of soil ageing on the recovery of POP's from spiked soil samples was also assessed. The average recovery of endosulfan compounds from slurry spiked soil (10, 20 and 40 microg g(-1)) was consistent (92.9 +/- 4.4% for n= 9). However, ageing of endosulfan compounds on the slurry spiked soil resulted in lower recoveries (average losses were 12.5% after 14 days ageing of slurry spiked soil). The uptake of POP's was assessed by measuring the amount of endosulfan compounds in roots and leaves from lettuce plants after 10, 20 and 33 days. In addition, control plants grown in uncontaminated soil were monitored and analysed. It was found that endosulfan compounds were present in the roots of all lettuce plants irrespective of soil spike level or age of plant. In the 33 day lettuce plants where the soil was spiked at the highest level (50 microg g(-1)) endosulfan compounds were determined in the leaves. The root to leaf ratio was found to be 3.1 for alpha-endosulfan, 46.0 for beta-endosulfan, and 24.3 for endosulfan sulfate. Spiked lettuce samples were subjected to in vitro gastrointestinal extraction to assess the bioavailability of endosulfan compounds. No detectable endosulfan compounds were determined in the gastric extracts while small quantities (range 0.06-0.12 microg g(-1)) were found in the intestinal extraction. All samples (soil and lettuce) were extracted using pressurised fluid extraction and analysed using gas chromatography with mass selective detection.     

Molecular characterisation of organic material in air fine particles (PM10) using conventional and reactive pyrolysis-gas chromatography-mass spectrometry

Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) was applied to study the composition of organic constituents in air particulate matter (PM10) collected inside an industrial area. A few milligrams of sampling filters containing air particles were pyrolysed at 700 degrees C directly (conventional) or after the addition of a derivatising reagent (tetramethylammonium hydroxide, TMAH, for pyrolysis-methylation; hexamethyldisilazane, HMDS, for pyrolysis-silylation). Py-GC-MS was also applied to synthetic polymers (poly(styrene-co-isoprene), polylimonene and polypinene) and vegetation samples (coniferous pollen, bark and resin) to identify markers indicative of possible precursors. Pyrolysates of PM10 showed the same suite of compounds in all the four seasons, dominated by hydrocarbons like styrene, limonene and clusters of isomeric alkenes with 14, 15 and 16 carbon atoms. Pyrolysis products of natural origin, including furaldehyde, benzeneacetonitrile, dehydroabietin and other diterpenoids were found, while no specific markers of synthetic rubbers were detected. The principal products released from reactive pyrolysis of PM10 were methyl or trimethylsilyl (TMS) derivatives of 1,6-anhydroglucose (levoglucosan), fatty acids, dehydroabietic acid and other resin acids along with hydroxy (di)carboxylic acids. Possible sources of the detected products (e.g. pine forest, biomass combustion) are discussed.     

Distribution and health-risk of polycyclic aromatic hydrocarbons in soils at a coking plant

Nineteen soil samples were collected in and around Songshan coking plant in Guangdong province of China and analyzed for eighteen polycyclic aromatic hydrocarbons (PAHs) by gas chromatography-mass spectrometry (GC-MS). The total concentration of PAHs ranged from 2.36 to 1146.39 mg kg(-1) dry weight, varying significantly among the sampling sites, most individual PAHs were correlated with each other. A cluster analysis was performed to examine the correlation of PAH distribution, five groups were observed with sample types in the coking plant. 2-3 ring PAHs were predominant in group I and II, while 4-5 ring PAHs showed great abundance in group III, IV and V, which contributed to the distance from the emission sources in the coking plant and the behaviors of particle-bound and gaseous PAHs. The ratios of Flu?:?(Flu + Pyr), BaA?:?(BaA + Chr), InP?:?(InP + BgP) and Ant?:?(Ant + Phen) ratios were 0.51-0.87, 0.16-0.89, 0.47-0.68 and 0.03-0.60, respectively. The total index of all studied soils was > 6, indicating that the source of the PAHs in coking plant soils were from the pyrolysis processes. Health risk assessments were carried out by dermal PAH exposure data to quantify cancer risk. The resultant lifetime exposure levels due to TEQ(BaP) desorbed onto skin for workers ranged from 2.25 × 10(-7) to 7.86 × 10(-5) mg kg(-1) per day, and the estimated cancer risks were between 8.45 × 10(-6) and 2.94 × 10(-3), indicating that the dermal exposures of PAHs to coking workers might be acceptable in most soil sites.     

Analysis of HO-PCBs and PCP in blood plasma from individuals with high PCB exposure living on the Chukotka Peninsula in the Russian Arctic

A trace analytical method is presented for the analysis of hydroxylated polychlorinated biphenyl metabolites (HO-PCBs) and pentachlorophenol (PCP) in human plasma. The described methodology is a modification of a previously validated method used for PCB and organochlorine pesticide analysis. The modified method enables the combined analysis of phenolic and neutral halogenated compounds. A tandem Florisil column is used for separating the HO-PCBs and PCP from the neutral fraction, instead of the more common chemical partitioning. In the same step the neutral fraction is purified for GC analysis. The extraction of the HO-PCBs and PCP was found to be highly dependent on sufficient acidification of the sample and the polarity of the extracting solvent. Analysis of plasma samples gave recovery rates for (13)C(6)-PCP and (13)C(12)-4-HO-CB 187 of 64 and 72%, respectively. The limit of detection ranged between 2-20 pg g(-1) plasma for the HO-PCBs and 5 pg g(-1) plasma for PCP. No matrix interferences were observed in the chromatograms. In plasma samples (n = 15) from the native Chukchi people in Uelen (Russian Arctic), a population with high PCB exposure, the median ratio of sum HO-PCBs to sum PCBs was as high as 0.4 and the sum HO-PCBs and PCBs were significantly correlated (r(2) > 0.7, p < 0.01). The median sum HO-PCBs (10 congeners) was 5920 pg g(-1) plasma with 4-HO-CB 107 as the dominating congener (median: 1670 pg g(-1) plasma). The median PCP level was measured at 642 pg g(-1) plasma.