Polycyclic Aromatic Hydrocarbons In Groundwater Research Articles

Seasonal distribution, source apportionment and risk assessment of polycyclic aromatic hydrocarbons in groundwaters in Owo, Southwestern Nigeria

Abstract The study focused on evaluating the seasonal distribution, source apportionment, and probabilistic risk assessment of polycyclic aromatic hydrocarbons (PAHs) in groundwater. Groundwater samples were obtained from Owo, southwestern Nigeria and subjected to liquid–liquid extraction and quantified using gas chromatography–mass spectrometry. Total PAH concentrations varied from about 180 to 23,600 ng/L during the dry season. The wet season, on the other hand, exhibited a wider range, from about 1,550 to 150,000 ng/L. Seasonal variations were also found in PAH types and concentrations, with relatively higher concentrations recorded during the wet season. Diagnostic ratios and positive matrix factorization indicated that coal/biomass combustion and traffic-related vehicular emissions were the prevalent sources of PAHs in groundwater. Health risk assessment indicated potential carcinogenic risks (incremental lifetime cancer risk (ILCR) > 1E − 04), while ecological assessment suggested medium (RQNC < 800 and RQMPC ≥ 1) and high ecological risks (RQNC ≥ 800 and RQMPC ≥ 1). The study reflected the need for effective mitigation strategies.

Evaluating the potential of wax impregnated reactive components for long-term acenaphthene removal

The catalytic oxidation of acenaphthene (ANA) was investigated using a controlled-release persulfate candle (PSC) and Fe(II) candle (Fe(II)C) to provide long-lasting oxidation conditions during groundwater remediation. To the best of our knowledge, this study is the first attempt to compare the pseudo-first-order rate constant (kobs) and % removal of ANA oxidation using PSC/Fe(II)C, PS solution (PSaq)/Fe(II) solution (Fe(II)aq), PSC/Fe(II)aq, and PSaq/Fe(II)C systems. The kobs and % removal of ANA in the PSC/Fe(II)C system exceeded those in the other systems. The optimal degradation conditions used were 0.1 mM ANA; 3.08 mM equilibrium concentration of PS (Ce,PS) released from PSC (controlled-release rate constant, kcr = 7.731 day−1); 5.673 mM equilibrium concentration of Fe(II) (Ce,Fe(II)) released from Fe(II)C (kcr = 3.796 day−1); unadjusted pH (~7.0); and 25 °C. Radical scavenger studies and electron spin resonance (ESR) spectra showed that sulfate (SO4•−) and hydroxyl (•OH) radicals were involved in the ANA oxidation, but •OH was the dominant radical species in the PSC/Fe(II)C system. Cl−, SO42−, and HCO3− acted as radical scavengers. The introduction of hydroxylamine (HA) into the PSC/Fe(II)C system resulted in a notable enhancement of ANA removal efficiency, increasing it from 51.8 % to 82.6 % within 10 min. Additionally, the PSC/Fe(II)C + HA system exhibited a higher Fe(II) consumption efficiency of 96.6 %, surpassing that of the PSC/Fe(II)aq + HA system, which registered an efficiency of 88.6 %. Intermediate byproducts after 24 h of reaction were detected as non-toxic byproducts by liquid chromatography-mass spectrometry (LC-MS). The PSC/Fe(II)C system would be beneficial for the remediation of polycyclic aromatic hydrocarbons in groundwater due to the continuous supply of Fe(II) and PS for a long time.

Kill two birds with one stone: Solubilizing PAHs and activating PMS by photoresponsive surfactants for the cycle remediation of contaminated groundwater

Polycyclic aromatic hydrocarbons (PAHs) represent a dangerous threat to the groundwater environment. PAHs are difficult to be effectively removed from groundwater because of their hydrophobicity. In this study, a combination of a Gemini photosensitive surfactant (N1, N2-bis[4-[4-[(4-butylphenyl) azo] phenoxy] butyl]-N1, N2-tetramethylethane-1,2-diammonium bromide, AzoPBT) with peroxymonosulfate (PMS) is developed to treat PAHs-contaminated groundwater. To investigate the reaction mechanism of the PMS/AzoPBT process, we chose naphthalene (Nap) and phenanthrene (Phe) as target pollutants. The quenching experiments, electron paramagnetic resonance (EPR) spectroscopy and the identified degradation products indicated that singlet oxygen could contribute to the degradation of PAHs. A tentative solution for Phe degradation was proposed based on the degradation products. The role of surfactant micelles in the PMS/AzoPBT process is further explored. The positively charged micelles in the PMS/AzoPBT process escalate the removal of PAHs by electrostatically polymerizing Br- and HSO5- in the solution. Although increasing the number of micelles can enhance the solubilization of PAHs by surfactant solutions, the encapsulation of PAHs by micelles can “protect” PAHs, which hinders the removal of PAHs. The PMS/AzoPBT process can be applied in a broad range of pH values. In the process of recycling AzoPBT to activate PMS to remediate groundwater, PAHs can be completely removed in the first cycle, and 51.4 % of them can be removed after four times of surfactant use. The combination of photoresponsive surfactants and PMS achieves efficient oxidation of PAHs without additional activators while increasing the solubility of PAHs in groundwater. This novel technology of PAHs-contaminated groundwater treatment may provide insights into the degradation mechanism of the PMS/AzoPBT process.

Estimation of Polycyclic Aromatic Hydrocarbons in Groundwater from Campania Plain: Spatial Distribution, Source Attribution and Health Cancer Risk Evaluation.

The aim of this study was to evaluate the concentrations of polycyclic aromatic hydrocarbons (PAHs) in 1168 groundwater samples of the Campania Plain (Southern Italy), taken using a municipal environmental pressure index (MIEP), and to analyze the distribution of these compounds to determine source PAHs using ratios of isomers diagnostic. Lastly, this study also aimed to estimate the potential health cancer risk in groundwaters. The data indicated that the highest concentration of PAHs was found in groundwater from Caserta Province and the contents of BghiP, Phe, and Nap were detected in the samples. The spatial distribution of these pollutants was evaluated using the Jenks method; moreover, the data indicated that incremental lifetime cancer risk ILCRingestion ranged from 7.31 × 10-20 to 4.96 × 10-19, while ILCRdermal ranged from 4.32 × 10-11 to 2.93 × 10-10. These research findings may provide information about the Campania Plain's groundwater quality and aid in the development of preventative measures to lessen PAH contamination in groundwater.

Analysis on Contamination Characteristics, Pollution Source Identification and Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbons of Groundwater in a Large Coking Plant Site of Province

Polycyclic aromatic hydrocarbons (PAHs), as a highly toxic persistent organic pollutant, are commonly found in soil and water environments. In recent years, the pollution of PAHs in groundwater has attracted wide attention from scientists. To study the pollution characteristics and sources of polycyclic aromatic hydrocarbon in groundwater of the coking site, 16 PAHs priorly controlled by the US EPA were analyzed and discussed. In this study, we identified the contamination characteristics of PAHs in groundwater, analyzed the pollution sources of PAHs, and evaluated the ecological risk of PAHs in the coking site by combining statistical techniques, the positive matrix factorization (PMF) model, and risk quotient (RQ) methods. The results indicated that the total detection rate of PAHs in groundwater of the coking plant was 46.7%. The concentrations of PAHs in groundwater of the coking plant ranged from below the detection limit to 444.9 μg·L-1, with the average value of 1.88 μg·L-1. The concentration of PAHs in the groundwater of different production workshops was significantly different. The most polluted workshop was in the tar-refining area, and the concentration of 16 PAHs was 444.9 μg·L-1. Based on the PMF model, we identified the two primary contamination sources of PAHs in groundwater of the coking plant:① oil combustion and ② coal and biomass combustion and oil leakage. The contribution ratios of the two sources to PAHs of groundwater were 38.6% and 61.4%, respectively. The results of the ecological risk assessment indicated that Σ16PAHs in groundwater of the coking plant had high ecological risk, and the ecological risk of single PAHs in 53.4% of the groundwater sampling site was at a high ecological risk level. In conclusion, it is urgent to carry out the treatment and restoration of the groundwater environment in the coking plant site.

Solubilization and remediation of polycyclic aromatic hydrocarbons in groundwater by cationic surfactants coupled nanobubbles: Synergistic mechanism and application

Polycyclic aromatic hydrocarbons pose a severe threat to groundwater and the soil environment. Improving the efficiency of the surfactant-enhanced remediation (SER) technique is a research hotspot. Nanobubbles (NBs) were introduced to enhance the solubilization effect of cationic surfactant dodecyltrimethylammonium bromide (DTAB) on phenanthrene (PHE). The interaction between NBs and DTAB was favorable in reducing the critical micelle concentration of DTAB. The equilibrium solubilization of DTAB to PHE was upgraded by up to 30.4% with the synergy of NBs. The effect of DTAB concentration on the stability of NBs was an essential reason for the different upgrade rates. The kinetic study showed that the process of equilibrium solubilization was accelerated, while NBs were “consumed”. Based on the classic DLVO framework, OH– and inorganic ions in groundwater can participate in the formation of micelles and change the double electric layer thickness of bubbles, which are the key factors affecting the stability of NBs. The results revealed the colloidal interface characteristics and the particle behavior of micelles with NBs, providing new insight into the combined application of micelles or vesicles with NBs.

Polycyclic aromatic hydrocarbons in groundwater of oil-rich regions of upper Brahmaputra Valley, India: linkages of colloidal transport

Polycyclic aromatic hydrocarbons in groundwater of oil-rich regions of upper Brahmaputra Valley, India: linkages of colloidal transport

Pollution Characteristics and Risks of Polycyclic Aromatic Hydrocarbons in Underground and Surface Drinking Water Sources in Northeast Inner Mongolia

Polycyclic aromatic hydrocarbons (PAHs) are hazardous and ubiquitous pollutants in the aquatic environment, and understanding the pollution characteristics and risk levels of PAHs is of great significance to the sustainable development of drinking water sources and drinking water safety. Hence, PAHs residues were measured qualitatively and quantitatively with solid-phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS) in 33 water samples (including 22 groundwater and 11 surface water samples) of the drinking water sources in the Manzhouli and Xinyouqi areas of northeast Inner Mongolia, and assessments of the pollution level of PAHs and the health and ecological risks were carried out. The results showed that PAHs were detected in all 33 sampling points of Manzhouli drinking water sources, except for benzo[k] fluoranthene, benzo[a] pyrene, and dibenzo[a,h] anthracene, with detection rates ranging from 36.36% to 95.45%; the detection rates of the other 13 PAHs monomers were 100%. The detection range of ρ（ΣPAHs） was 42.76-164.50 ng·L-1, and the mean value was 90.82 ng·L-1. The detection ranges of ρ（ΣPAHs） in surface water and groundwater were 66.39-164.50 ng·L-1 and 42.76-147.70 ng·L-1, respectively. The concentration of the detected naphthalene was the highest, with a mean value of 36.91 ng·L-1, and the concentration of anthracene was the lowest, with a mean value of 0.81 ng·L-1; there were no significant differences among the concentrations of all the PAHs monomers of the surface and groundwater (P>0.05). The pollution of PAHs was at a median level in China and abroad, mainly in the middle and low loops (3-4 loops). The analysis of the sources of PAHs in groundwater and surface water in Manzhouli using the ratio feature method and principal component analysis showed that the PAHs in the drinking water source water bodies in the Manzhouli area were mainly affected by the combustion of coal and biomass and oil, and some surface water sources were affected by the oil source. The human health and ecological risk assessment results showed that the water body of drinking water would not cause health risks to the human body, and the ecological risk was at a medium level; however, the high risk of benzo[b] fluoranthene (BbF) monomer production should be continuous cause for concern. From the perspective of the sustainable development of drinking water sources and drinking water safety, the necessary supervision and protection measures should be considered to prevent further pollution. The results of this research provide a scientific basis for the pollution control and prevention and control of PAHs in drinking water sources.

Distribution, source and ecological risk assessment of polycyclic aromatic hydrocarbons in groundwater in a coal mining area, China

The impact of exposure to polycyclic aromatic hydrocarbons (PAHs) on the ecological environment has aroused widespread concern in coal mining areas. Coal mining and solid waste accumulation are among the main reasons for the widespread occurrence of PAHs in groundwater in mining areas. In this study, the PAH content in groundwater in a coal mining area in northern Anhui, China, was determined via gas chromatography–mass spectrometry (GC–MS). The seasonal variation, composition, spatial distribution and sources of PAHs were analyzed, and their potential ecological risks were evaluated. The concentration of ∑PAHs in groundwater ranged from 15.04 to 449.13 ng/L, mainly including 2- and 3-ring PAHs. There were obvious differences in the PAH distribution in groundwater, and higher PAH concentrations were detected in groundwater near industrial parks and solid waste dumping areas. Diagnostic ratio analysis indicated that the PAHs mainly originate from the combustion of coal, biomass and petroleum. The positive matrix factorization (PMF) results revealed that coal and biomass combustion, traffic emissions, coking emissions and oil leakage contributed 46.59%, 20.06%, 18.70% and 14.65%, respectively, to the detected PAHs. The ecological risk assessment results indicated that this area experienced a moderate ecological risk, and the mean ecological risk values during the wet season were lower than those during the dry season.

Source, Partition and Ecological Risk of Polycyclic Aromatic Hydrocarbons in Karst Underground River Environment, Southern China

As the main source of drinking water in the karst areas of southern China, underground rivers play an important supporting role in local economic and social development. However, due to the special aquifer structure in the karst areas of southern China, polycyclic aromatic hydrocarbons (PAHs) can easily enter the water environment of underground rivers and cause serious pollution, which will affect the water quality safety. In this study, Qing-shui Spring underground river in Nanning city was selected as a representative of the typical underground river in southern China, and the pollution characteristics, source analysis, ecological risk assessment and diffusion law of PAHs were studied. The results showed that the total concentration of PAHs in groundwater and surface sediments was in the range of 282.42–464.88 ng/L and 400.14–1194.69 ng/g, respectively, and the overall concentrations of PAHs were below the moderate pollution level. Pollutant discharge and physical and chemical properties of PAHs caused the concentrations of PAHs to decrease gradually from upstream to downstream, but the proportion of high-cyclic PAHs increased gradually. According to the source analysis results of the ratio method, PAHs sources in groundwater were mainly biomass combustion sources in the upstream, oil sources in the middle and mixed sources in the downstream. Sediment and groundwater had some differences. The middle and upper reaches were the source of biomass combustion, while the middle and lower reaches were the mixed source. The ecological risk assessment results showed that the ecological risk of groundwater was at a moderate level, while the ecological risk of sediment was at a low level. Benzo[a]anthracene (BaA) and benzo[b]fluoranthene (BbF) in groundwater and acenaphthylene (Acy) and fluoranthene (Flu) in sediment should be monitored intensively. Appropriate control measures should be put in place to prevent further pollution. Partition coefficients varied from 0.73 to 3.85 L/g in the sediment–water interface, increasing with the rise of PAH compounds. All of the organic carbon partition coefficients (Koc) in the sediment–water interface were higher than predicate values based on the typical model of equilibrium distribution; this indicated that PAHs were strongly adsorbed in the sediment. The linear free energy relationship coefficient between the Koc value and the n-octanol-water partition coefficient (Kow) was 0.85 but the slope was lower than 1, indicating that sediment in the Qing-shui Spring underground river had weak lipophilic characteristics and adsorption ability for PAHs. The results can provide a reference for the risk assessment and pollution control of PAHs in the karst underground rivers in South China.

Evaluation and risk assessment of polycyclic aromatic hydrocarbons in groundwater and soil near a petroleum distribution pipeline spill site, Eleme, Nigeria

Evaluation and risk assessment of polycyclic aromatic hydrocarbons in groundwater and soil near a petroleum distribution pipeline spill site, Eleme, Nigeria

Sources and pollution path identification of PAHs in karst aquifers: an example from Liulin karst water system, northern China

Karst water, with constituting major sources for water supply worldwide, is vulnerable and prone to be polluted. In this study, it is reported that karst water polycylic aromatic hydrocarbons (PAHs) pollution is caused by the infiltration of surface runoff in the bared carbonate areas, which is of universal significance for the protection of groundwater resources in karst region. Hydro-geochemistry, stable isotopes (δD, δ18O and 87Sr/86Sr) and characteristic ratio method were conducted together to illustrate the concentration, distribution, sources and pollution path of polycyclic aromatic hydrocarbons in groundwater in the Liulin karst water system of northern China. The results showed that total concentration of polycyclic aromatic hydrocarbons ranged from 39.25 to 16,830 ng/L in groundwater, with Naphthalene being the dominant component, and the median value increased gradually along the flow path. The highest polycyclic aromatic hydrocarbons concentrations in karst water were mainly observed in the coal mining and the discharge areas. Based on the characteristic ratios, the polycyclic aromatic hydrocarbons in the study area mainly come from local incomplete combustion of woods, fossil fuels, coal and liquid fuels. The slight shift of δD and δ18O and moderate 87Sr/86Sr ratios suggest that the polycyclic aromatic hydrocarbons in karst water is mainly polluted by surface runoff during rain events in the bared karst region. The leakage of river water may partly contribute to the polycyclic aromatic hydrocarbons in some karst water, which normally located close to the karst water - river water mixing line. This study provides a new technical method for tracing the sources and identifying the pollution paths of organic pollution in a karst water system.

Polychlorinated Biphenyls and Polycyclic Aromatic Hydrocarbons in Groundwater of Fuel-Impacted Areas in Ado-Ekiti, Nigeria

Polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyl (PCB) congeners in groundwater samples from selected fuel stations in Ado-Ekiti, Southwestern Nigeria, were analyzed to investigate the impact of increased anthropogenic activities. Qualitative and quantitative evaluations of the PAHs and PCBs were done using gas chromatography coupled with appropriate detectors. The PAHs concentrations ranged from ND − 0.98 mg/L, while the PCBs ranged from ND − 164 µg/L. The study reflected that NNPC sampling point had the least contaminated with PCBs, whereas 5Os evinced the highest. The concentrations of the high molecular weight PAHs were generally high compared to low molecular weight PAHs. Using specific ratio distribution, PAH fingerprints suggest pyrogenic origin. Further statistical analysis revealed that 69.0% of the PCBs congeners showed significant difference among the sampling sites with RIHD and 5Os contributing values responsible for the significant levels, while Chi-square revealed no significant difference in the PAHs levels.

Influencing factors and health risk assessment of polycyclic aromatic hydrocarbons in groundwater in China

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants. This study investigated the occurrence of 16 PAHs in groundwater of representative regions of China (the cities of Lanzhou, Shijiazhuang, and Golmud and in Du’an County) using a gas chromatograph mass spectrometer. The total concentrations of 16 PAHs (∑PAHs) were in the range 0–29.06 μg/L (average: 594.8 ng/L). Acenaphthylene (Acy) and Naphthalene (Nap) had the highest detected frequency (74.56 %) and highest average concentration (632.7 ng/L), respectively. The average concentration of ∑PAHs in each study area exhibited the following trend: Lanzhou > Golmud > Du’an dry season > Du’an wet season > Shijiazhuang. The dominant PAHs in the study areas comprised mainly 2–4-ring PAHs, i.e., Nap (38.71 %; Shijiazhuang), BaA (40.09 %; Du’an wet season), Ace (16.84 %; Du’an dry season), Nap (43.51 %; Lanzhou), and BaA (57.43 %; Golmud). Overall, the PAHs of 101 samples were derived primarily from combustion and a small number of samples of PAHs originated from petroleum sources. Owing to strong adsorption in the vadose zone, the concentrations of PAHs in Shijiazhuang groundwater were lower than those in the groundwater of Golmud and Du’an. The groundwater in Du’an, Lanzhou and Golmud exhibits potential carcinogenic risk if consumed without further treatment.

Occurrence of polycyclic aromatic hydrocarbons in groundwater from rural areas in eastern China: Spatial distribution, source apportionment and health cancer risk assessment

Polycyclic aromatic hydrocarbons (PAHs) pollution in well water has become more widespread, especially in rural areas. The development of small workshops has brought economic growth; however, a sharp increase in the level of pollution due to combustion of fossil fuels has also been observed. A lack of effective measures to control environmental pollution and strict legislation in these regions can contribute to higher PAHs emissions. In the study, the distribution and level of 16 PAHs in well water in rural eastern China were reported. The total concentrations of 16 priority PAHs varied from 4 to 169 ng/L, and an arithmetic mean of 38 ± 25 ng/L. Moreover, the highest PAHs content was found in well water from Shandong Province, and the average concentration was 60 ± 48 ng/L. The distribution of total 16 PAHs illustrated a decreasing trend from north to south. However, the distribution of PAHs with 2-rings and 4-rings was found to be higher in Jiangsu and Hebei province, respectively. The PAHs source identification results showed that the dominant source was coal and biomass combustion, which was consistent with the local conditions. The values of health cancer risks (CRs) were calculated, and that indicated that hazard quotients of nine non-carcinogenic contaminants were lower than one and might not have negative health risks. However, for carcinogenic PAHs, CRs values of the dermal pathway were higher than 10−6, and those for benzo [a]pyrene (BaP) and dibenzo [a, h] anthracene (DbA) were even higher (>10−4), indicating significant high risks to children and adults.

Simultaneous determination of 16 polycyclic aromatic hydrocarbons in groundwater by GC-FID after solid-phase extraction

Groundwater contamination by polycyclic aromatic hydrocarbons (PAH) may pose a risk to human health, as these compounds are considered to be highly toxic, carcinogenic and/or mutagenic and bioaccumulative. The aim of this study was to evaluate and determine PAH levels in groundwater samples collected from tubular wells in a city of northern Brazil by gas chromatography with flame ionization detector (GC-FID) used by the population for consumption. Sample pre-treatment using solid-phase extraction cartridges was performed in order to promote an enrichment of the PAH fraction of interest and to remove interferences from the matrix to further determine PAH in samples by GC-FID. The results obtained showed that all groundwater samples studied presented PAH levels lower than maximum values allowed by MS 2914/2011 and CONAMA 396/2008. The developed procedure is characterized by low limits of detection and quantification, equal to 0.024–0.113 µg L−1 and 0.079–0.378 μg L−1, respectively, good linearity (r2 > 0.99). The recoveries obtained for 16 PAH by the addition and recovery method ranged from 85.4 to 105.7% with good precision (RSD < 5.0%). The results of this study showed that the method developed is fast, accurate and robust with high efficiency for identification and determination of 16 PAH in groundwater samples.

Determination of Polycyclic Aromatic Hydrocarbons in Commercial Parenteral Formulations and Medications Using High-Performance Liquid Chromatography with Diode Array Detection.

HPLC coupled to UV diode array detection (DAD) is proposed for the determination of polycyclic aromatic hydrocarbons (PAHs) in pharmaceutical products for parenteral administration. Because rubber is a possible source of PAHs for these products, samples stored in containers with rubber parts were selected for the analysis. The basis for method optimization was EPA Method 8310, which determines 16 priority PAHs in ground water and wastewater by HPLC using both UV and fluorescence detection. Using DAD, two channels were selected for detection, with one operating at 254 nm for the detection of nine PAHs and the other at 225 nm for the detection of seven PAHs. This method allowed for the detection of PAHs using external calibration with LODs and LOQs ranging from 0.001 to 0.060 µg/mL and from 0.003 to 0.167 µg/mL, respectively. Within-day precision, expressed as RSD, varied from 1.24 to 7.76% for PAH concentrations from 0.05 to 0.50 µg/mL, and intraday precision varied from 3.10 to 9.40% for the same concentration range. Method accuracy was confirmed by recoveries of 75-120% of the spiked samples. This method was applied for the determination of PAHs in three commercial infusion solutions and in nine different medications stored in syringes prior to administration to patients. Twelve of 16 PAHs were found in these samples. Total PAH concentrations varied from 0.13 to 13.50 µg/mL. Pyrene was the most prevalent contaminant, being present in 11 of 12 samples in concentrations ranging from 0.17 to 4.80 µg/mL. This method presented good sensitivity for the measurement of PAH in the target samples, allowing for the determination of the 16 priority PAHs in one run and in 30 min.

Determination of Polycyclic Aromatic Hydrocarbons in Commercial Parenteral Formulations and Medications Using High-Performance Liquid Chromatography with Diode Array Detection.

HPLC coupled to UV diode array detection (DAD) is proposed for the determination of polycyclic aromatic hydrocarbons (PAHs) in pharmaceutical products for parenteral administration. Because rubber is a possible source of PAHs for these products, samples stored in containers with rubber parts were selected for the analysis. The basis for method optimization was EPA Method 8310, which determines 16 priority PAHs in ground water and wastewater by HPLC using both UV and fluorescence detection. Using DAD, two channels were selected for detection, with one operating at 254 nm for the detection of nine PAHs and the other at 225 nm for the detection of seven PAHs. This method allowed for the detection of PAHs using external calibration with LODs and LOQs ranging from 0.001 to 0.060 &#x03BC;g/mL and from 0.003 to 0.167 &#x03BC;g/mL, respectively. Within-day precision, expressed as RSD, varied from 1.24 to 7.76% for PAH concentrations from 0.05 to 0.50 &#x03BC;g/mL, and intraday precision varied from 3.10 to 9.40% for the same concentration range. Method accuracy was confirmed by recoveries of 75&#x2013;120% of the spiked samples. This method was applied for the determination of PAHs in three commercial infusion solutions and in nine different medications stored in syringes prior to administration to patients. Twelve of 16 PAHs were found in these samples. Total PAH concentrations varied from 0.13 to 13.50 &#x03BC;g/mL. Pyrene was the most prevalent contaminant, being present in 11 of 12 samples in concentrations ranging from 0.17 to 4.80 &#x03BC;g/mL. This method presented good sensitivity for the measurement of PAH in the target samples, allowing for the determination of the 16 priority PAHs in one run and in 30 min.

Occurrence and source apportionment of PAHs in highly vulnerable karst system

The concentration and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in topsoil, groundwater and groundwater suspended solids (SS) at Guozhuang karst water system of northern China were investigated. The total concentration of PAHs ranged from 622 to 87,880ng/g dry weight in topsoil, from 4739 to 59,314ng/g dry weight in SS, and from 2137 to 9037ng/L in groundwater, with mean values of 17,174ng/g, 11,990ng/g and 5020ng/L, respectively. High concentrations of PAHs were mainly observed in the coal mining industrial area and the discharge area. The composition of PAHs indicated that low molecular weight PAHs were predominant in groundwater samples, the content of medium molecular weight PAHs was elevated in SS, and carcinogenic high molecular weight PAHs were frequently detected in topsoil. The high contents of low-medium molecular weight PAHs in groundwater and SS suggested relatively recent local sources of PAHs that were transported into the aquifer via leakage of contaminated surface water and/or infiltration of PAH-containing precipitation. The results of evaluating sources of PAHs using ratios of specific PAH compounds showed that PAHs mainly originated from coal and wood combustion. Furthermore, five sources were identified by positive matrix factorization (PMF) model, and the contribution to the total loadings of groundwater PAHs were: 2% for unburnt oil, 32% for coal combustion, 22% for vehicle emission, 27% for biomass combustion and 18% for coke production, respectively. Furthermore, strong correlations of total PAHs with total organic carbon (TOC) in topsoil indicated co-emission of PAHs and TOC. Poor correlations of PAHs with dissolved organic carbon (DOC) in groundwater indicated that other factors exert stronger influences. Therefore, PAHs might have posed a major threat to the quality of potable groundwater in Guozhuang karst water system.

PAHs contamination in groundwater from a part of metropolitan city, India: a study based on sampling over a 10-year period

Presence of polycyclic aromatic hydrocarbons (PAHs) in the soil and water is of serious environmental concern as they are carcinogenic in nature. The present study was carried out with an aim to identify the presence of PAHs in groundwater of Chennai, Tamil Nadu, India. This is an industrialised area where petrochemical storage tanks are located. Groundwater sampling was carried out in the years 2001, 2011 and 2012 to understand the variation in PAHs content in this area. Concentration of major ions, pH and EC were measured during the year 2001. Of the 24 groundwater samples collected in the year 2001, most of them were alkaline and 62.5 % were not permissible for drinking based on pH and EC, respectively. Influence of seawater was the major reason for the Na–Cl dominant nature of groundwater. TPH and PAHs analysis of groundwater carried out in 2001 and 2011, and physical examination of groundwater in 2012 indicate the increased level of contamination in the eastern part of the study area. The contamination in the eastern part persists because of the fact that groundwater is flowing towards the east and also due to the presence of petrochemical storage tanks near the coast. Thus this area is affected by PAHs pollution which has endured over the past 50 years. An underground storage tank that was functioning in this area was closed about 50 years ago and leakage of PAHs from this tank was reported in the year 1993. However, the present study indicates the decrease in the area of zone of pollution, possibly due to natural flushing of groundwater zone.