Insight into the effect mechanism of sedimentary record of polycyclic aromatic hydrocarbon: Isotopic evidence for lake organic matter deposition and regional development model.

Deciphering the temporal patterns of polycyclic aromatic hydrocarbons (PAHs) in sediment cores, and the effect mechanism of sedimentary organic matter (OM) and regional development model on PAHs are crucial for pollution control and environmental management. Herein, sediment core was collected from Chenhu international wetland in Wuhan, central China. Meanwhile, historical trend and source of PAHs and sedimentary OM were presented, respectively. Result demonstrated that the most significant growth of PAHs (increased by 158.8%) was attributed to the significant enhancement of traffic emission (5.57 times), coal combustion (4.59 times), and biomass burning (8.09 times). Similarly, the percentage of phytoplankton (stage Ⅲ: 37.9%; stage Ⅳ: 31.2%) and terrestrial C3 plants (stage Ⅲ: 24.6%; stage Ⅳ: 29.2%) to sedimentary OM hold the dominant position after the stage Ⅱ. The obvious shifts of historical trend and sources in PAHs were highly related to economic development models (r = 0.72, p < 0.001) and sedimentary OM (r = 0.82, p < 0.001). It demonstrated that eutrophication of lake accelerated the burial of PAHs. Redundancy analysis results suggested that TOC was dominating driver of sedimentary PAHs (16.56%) and phytoplankton occupied 9.58%. To further confirm the significant role of economic development models, three different historical trends of PAHs in different regions of China were presented. The result of this study provides the new insight into the geochemistry mechanism of lake sedimentary OM and PAHs. Meanwhile, the relationship of regional development model and sedimentary PAHs was highlighted in this study. Significantly, the main environmental implications of this study are as follows: (1) lake eutrophication of phytoplankton OM accelerated the burial of PAHs in lake sediment; (2) economic development models and energy structure significantly influence the sedimentary PAHs. This study highlights the coupling relationship between OM burial and PAHs sedimentation, and the importance of accelerating the transformation of economic energy structure.

New insight into the geochemical mechanism and behavior of heavy metals in soil and dust fall of a typical copper smelter.

The desorption mechanism of heavy metals (HMs) in soil around the mining region are complex and affected by multiple pollution sources, including sewage discharge and atmospheric deposition. Meanwhile, pollution sources would change soil physical and chemical properties (mineralogy and organic matter), thus affecting the bioavailability of HMs. This study aimed to investigate the pollution source of HMs (Cd, Co, Cu, Cr, Mn, Ni, Pb, and Zn) in soil near mining, and further evaluate influence mechanism of dust fall on HMs pollution in soil by desorption dynamics processes and pH-dependence leaching test. Result presented that dust fall is the primary pollution source to HMs accumulation in soil. Additionally, the result of mineralogical analysis in dust fall revealed that quartz, kaolinite, calcite, chalcopyrite, and magnetite are the major mineralogical phases by XRD and SEM-EDS. Meanwhile, the abundance of kaolinite and calcite in dust fall is higher than in soil, which is the primary reason of higher acid-base buffer capacity of dust fall. Correspondingly, the weakened or disappeared of hydroxyl after the adding acid extraction (0-0.4 mmol· g-1) demonstrated that hydroxyl is the main participants of HMs absorption in soil and dust fall. These combined findings suggested that atmospheric deposition not only increases the pollution loading of HMs in soil, but also changes the mineral phase composition of soil, which would increase the adsorption capacity and bioavailability of HMs in soil. This is very remarkable that heavy metals in soil influenced by dust fall pollution could be released preferentially when soil pH is changed. The present results of this study would provide efficient and scientific targeted strategies for pollution control of HMs in soil near mining areas.

Bioavailability and regional transport of PM2.5 during heavy haze episode in typical coal city site of Fenwei Plain, China.

Despite the decrease in anthropogenic emissions, haze episodes were still frequent in the Fenwei Plain, which was identified as one of the three key areas for air pollution control. Herein, PM2.5 samples were collected to investigate the influence of festival effect during the Chinese Spring Festival from February 2rd to 13th, 2019, in Linfen on the Fenwei Plain. The characteristics of element pollution, enrichment factor, source apportionment, regional transport of PM2.5, and health risk assessment were discussed. Meanwhile, the simulated lung fluid method (SLF) was carried out to accurately assess the inhalation risks of heavy metals (HMs). Results indicated that the average concentration of PM2.5 was 195.6 µg·m-3 during the studying period. Road fugitive dust (15.6%), firework burning source (25.6%), industrial emission (30.5%), and coal combustion (28.3%) were identified by positive matrix factorization (PMF) modeling. Using the HYSPLIT trajectory model, air masses from the central Shaanxi, southern Hebei, and northern Henan were the dominant transport paths during the Spring Festival, which contributed 21.9 and 41.2% of total trajectories, respectively. The findings that high PSCF and CWT levels were found in central Shaanxi, southern Hebei, and northern Henan were confirmed. The SLF mean bioaccessibility (%) of the solubility of particulate metals was in order of Mn > Ni > Sb > Ba > Zn > Pb > Cr. However, the carcinogenic risk value of Cr was the highest, exceeding the maximum acceptable risk. The present study provided important information for further analyzing the air pollution cause of Fenwei Plain.

On-road emissions of fine particles and associated chemical components from motor vehicles in Wuhan, China.

Vehicle emission is an important contributor to urban air pollution with the increasing number of motor vehicles. Ten typical vehicles were selected in Wuhan to study the emissions of fine particular matters (PM2.5) and associated chemical components by on-road tests through a Portable Emission Monitoring System (PEMS). The emission factors of PM2.5 and the compositions of it from different types of vehicle were obtained. Results showed that the average emission factors of PM2.5 from gasoline and diesel vehicles were 1.266 and 16.589 mg/km. As the emission standard of vehicles increased from China III to China V, PM2.5 emission factor gradually decreased from 17.385 to 1.520 mg/km. Emission rate of PM2.5 was 0.0384 mg/s under low speed, and it increased to 0.0775 and 0.0964 mg/s under the medium and high speeds. The ratio of organic carbon versus elemental carbon (OC/EC) in PM2.5 from gasoline vehicles was 6.89, which was greater than that of diesel vehicles as 3.12. Because gasoline was made of small molecules and the compression ratio of gasoline engine was relatively low, some OC remained in the area where the ignition failed in the cylinder. The top four water-soluble ions with high emission factors were Cl-, SO42-, Ca2+, and Na+, while K, Na, Ca and Mg had a larger emission factors in the 21 tested inorganic elements. These water-soluble ions and inorganic elements mainly came from the oil burning, fuel additives and engines wear. Results of PM2.5 emission characteristics would help to improve the air quality in Wuhan.

Variation of pollution sources and health effects on air pollution before and during COVID-19 pandemic in Linfen, Fenwei Plain.

Stringent pollution control measures are generally applied to improve air quality, especially in the Spring Festival in China. Meanwhile, human activities are reduced significantly due to nationwide lockdown measures to curtail the COVID-19 spreading in 2020. Herein, to better understand the influence of control measures and meteorology on air pollution, this study compared the variation of pollution source and their health risk during the 2019 and 2020 Spring Festival in Linfen, China. Results revealed that the average concentration of PM2.5 in 2020 decreased by 39.0% when compared to the 2019 Spring Festival. Organic carbon (OC) and SO42- were the primary contributor to PM2.5 with the value of 19.5% (21.1%) and 23.5% (25.5%) in 2019 (2020) Spring Festival, respectively. Based on the positive matrix factorization (PMF) model, six pollution sources of PM2.5 were indicated. Vehicle emissions (VE) had the maximum reduction in pollution source concentration (28.39 µg· m-3), followed by dust fall (DF) (11.47 µg· m-3), firework burning (FB) (10.39 µg· m-3), coal combustion (CC) (8.54 µg· m-3), and secondary inorganic aerosol (SIA) (3.95 µg· m-3). However, the apportionment concentration of biomass burning (BB) increased by 78.7%, indicating a significant increase in biomass combustion under control measures. PAHs-lifetime lung cancer risk (ILCR) of VE, CC, FB, BB, and DF, decreased by 44.6%, 43.2%, 34.1%, 21.3%, and 2.0%, respectively. Additionally, the average contribution of meteorological conditions on PM2.5 in 2020 increased by 20.21% compared to 2019 Spring Festival, demonstrating that meteorological conditions played a crucial role in located air pollution. This study revealed that the existing control measures in Linfen were efficient to reduce air pollution and health risk, whereas more BB emissions were worthy of further attention. Furthermore, the result was conducive to developing more effective control measures and putting more attention into unfavorable meteorological conditions in Linfen.

Supergene geochemistry of arsenic and activation mechanism of eucalyptus to arsenic source.

Arsenic (As) migration and transformation in the supergene environment and eucalyptus planting have essential effects on ecology or even human health, respectively. However, the combined environmental impact of As migration and transformation and eucalyptus planting has not been studied. Here we report a case of soil As contamination caused by eucalyptus planting and address the fate of As in Longmen county, Guangdong Province, China. We found high As content in weathered arsenopyrite bearing granite or granite-derived soil, where a large area of eucalyptus is planted. The release of organic acids from eucalyptus roots promoted the electrochemical reaction of arsenopyrite to produce AsO33-. In the subsequent supergene migration process, As species change from arsenite to arsenate with the addition of oxygen and the effect of clay minerals, last with As infiltration, precipitation, and enrichment, forming the As contamination in soil. The whole process reveals the activation process of eucalyptus to the As source (arsenopyrite), the migration and transformation process of As in the supergene environment, and the formation mechanism of soil As contamination. This finding provides a new perspective of soil As contamination around arsenopyrite bearing granite of the Nanling area with eucalyptus planting and proposes that the negative effects of Nanling eucalyptus planting may be greater than expected.

Background levels of OCPs, PCBs, and PAHs in soils from the eastern Pamirs, China, an alpine region influenced by westerly atmospheric transport.

Long-range atmospheric transport (LRAT) plays a crucial role in the occurrence of persistent organic pollutants (POPs) in remote regions. When studying the LRAT of POPs on the Tibetan Plateau, westerly-controlled regions have received insufficient attention compared with regions influenced by the Indian monsoon or air flow from East Asia. We investigated the residual levels of POPs in soils from the eastern Pamirs and used air backward trajectory analysis to elucidate the influence of potential source regions via LRAT. Organochlorine pesticides (OCPs, mainly comprising DDTs, HCHs, and HCB), polychlorinated biphenyls (PCBs, mainly comprising penta- and hexa-CBs), and polycyclic aromatic hydrocarbons (PAHs, mainly comprising three- and four-ring) were detected at low concentrations of 40-1000,

First High-Resolution Emission Inventory of Levoglucosan for Biomass Burning and Non-Biomass Burning Sources in China.

Levoglucosan (LG) emitted from non-biomass burning (non-BB) sources has given rise to biased or even unreasonable source identification results when adopting LG as a distinct marker of biomass burning (BB). The estimation of LG emission and its spatiotemporal variation for various sources are the keys to reducing uncertainty. This study first developed a LG emission inventory for China from 25 sub-type sources belonging to eight categories, with a 3 km × 3 km spatial resolution and monthly distribution. The total LG emission in 2014 was 145.7 Gg. Domestic BB and open BB contributed 39.2 and 34.3% of the total emission. Non-BB sources, including municipal solid waste burning (9.7%), firework burning (9.6%), meat cooking (5.4%), domestic coal burning (1.5%), ritual item burning (0.2%), and industrial coal burning (0.1%), contributed to 26.5% of the total emission. LG emission varied spatially and temporally. Non-BB sources have a significant spatiotemporal impact on BB source contributions, even in high BB emission regions or in sowing, harvesting, and winter heating seasons. The local BB contributions have been substantially overestimated by 4.28-369% in previous studies, wherein LG was solely referred to as the BB source. By 2018, LG emission from BB might decrease to 63.9% of its total emission. This high-resolution LG emission inventory can be greatly useful for source identification studies in China. It also supports future research on the modeling of smoke aging and pollution control.

Assessment of commercial porous polyethylene frit for extraction of polycyclic aromatic hydrocarbons from water.

Exploring commercial and inexpensive sorbents for extraction of organic pollutants is still an active area of research. Ultrahigh molecular weight polyethylene sieve plate (UMPESP) is a commercially available, low-cost, and porous frit, which has been widely used in solid-phase extraction cartridges to fix the filling materials. In this work, UMPESP was investigated for the extraction of polycyclic aromatic hydrocarbons (PAHs) from water samples. The desorption and sorption efficiencies of UMPESP were first evaluated and compared with two previously reported sorbents, low-density polyethylene plastic pellet (LDPEP) and silicone rod (SR). The comparative results showed that quantitative desorption of analytes from UMPESP, which could be easily achieved with 2 × 1.5 mL n-hexane, was more effective than that of LDPEP (>6 × 1.5 mL n-hexane) and comparable to that of SR. Additionally, shorter equilibrium time was rendered by UMPESP (shaking for 120 min) compared with SR (>480 min), due to the porous structure and larger surface area of the former. Different parameters that affect the extraction efficiency, including organic modifier, ionic strength, and pH value, were then studied. The optimized method coupled with gas chromatography-mass spectrometry afforded good linearity in a concentration range of 10-5000 ng L-1 (except acenaphthene in the range of 25-5000 ng L-1) with coefficients of determination ranging from 0.9957 to 0.9995 and relative standard deviations below 13.8%. The limits of detection and quantification were 0.04-3.35 ng L-1 and 0.13-11.16 ng L-1, respectively. Finally, the method was successfully applied to determine PAHs in real water samples, and the results showed no statistically significant difference with the concentrations derived from liquid-liquid extraction.

Occurrence of N-nitrosamines and their precursors in the middle and lower reaches of Yangtze River water.

The presence of some types of N-nitrosamines in water bodies is of great concern worldwide due to their carcinogenic risks and harmful mutagenic effects on human health. In the present study, eight N-nitrosamines and their formation potentials (FPs) were primarily investigated in Yangtze River surface water to evaluate their spatial distribution, mass loads, and ecological risks. The results showed that of the eight N-nitrosamines investigated, NDMA (<1.5-17 ng/L), NDEA (<1.4-9.5 ng/L), NDPA (1.0 ng/L), NMOR (<1.0-1.3 ng/L), NPIP (<2.1-3.7 ng/L), and NDBA (<3.6-30 ng/L) were detected. The FPs of NDMA (<27-130 ng/L), NDEA (<0.9-2.3 ng/L), NDPA (<1.2-1.9 ng/L), NPYR (<1.4-2.9 ng/L), NMOR (<1.0 ng/L), and NDBA (<1.1-14 ng/L) were significantly identified. NDBA was predominantly observed in surface water, while NDMA was noticeably detected in chloraminated water samples. It was estimated that approximately 5.4 t/y of N-nitrosamines were carried by the Yangtze River to the East China Sea, whereas the input flux of N-nitrosamine precursors was estimated to be approximately 69.5 t/y. Spatial variations were observed due to the input of N-nitrosamines from the upstream dams and lakes. The origin of N-nitrosamine precursors was not associated with the presence of sediment in river water. NDEA could be introduced into river water by the discharge of wastewater. NDBA and its precursors could originate from industrial and aquaculture activities. NDMA and its precursors could result from both of the aforementioned sources. Moreover, the wastewater discharge from small cities, pH value, wastewater treatment ratio, and dilution could be the key factors that influence the occurrence of N-nitrosamines along the Yangtze River. More attention should be paid to the cancer risks posed by N-nitrosamines. The ecological risks posed by N-nitrosamines in the Yangtze River can be ignored.

Level, source, and distribution of organochlorine pesticides (OCPs) in agricultural soils of Tanzania.

This study investigated the level, composition, and spatial and vertical distribution of the organochlorine pesticides (OCPs) at 0-2 cm and 2-20 cm in the agricultural surface soils from Southeastern to Central-western Tanzania. Although the most abundant OCPs were DDT with a mean concentration of 2.29 ng/g, dieldrin (1.57 ng/g), and methoxychlor (0.79 ng/g), HCH was the most dominant (with detection frequency of 88%). OCP dominance was in the Southern Highlands, which is the most productive agricultural zone. Though there were indicators of recent inputs for some sites, OCP contamination was mainly historical. DDT contamination was dominated by p,p'-DDE and resulted from both technical DDT and dicofol while HCH contamination was dominated by γ-HCH and resulted from both technical HCH and lindane. Based on depth, the OCPs dominated mainly the upper 2 cm, which was associated with soil and environmental factors rather than recent inputs since most of the detected compounds were historical. Nevertheless, some sites showed exceptional high abundance in the lower soil with more concentration of parent compounds. Therefore, this study recommends the need for further studies on the influence of soil properties on OCPs' transport in the soil, surface water, and air. Besides, detection of recent inputs at some sites calls for more mapping of the OCPs in the country to strengthen their control and prevention of future risks.

Historical residues of organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in a flood sediment profile from the Longwang Cave in Yichang, China.

Historical residual of persistent organic pollutants (POPs) in flood sediment from a karst cave were investigated. Fifteen vertical sediment samples were collected from a 6 m-deep flood sediment profile in the Longwang Cave, and the concentrations of organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and particle size distribution in the sediments were analysed. The concentrations of OCPs and PAHs varied from 0.85 ng g-1 to 63.1 ng g-1 (mean 8.11 ng g-1) and 5.05 ng g-1 to 82.6 ng g-1 (mean 13.9 ng g-1), respectively; major PAHs in the profile were 2- and 3-ringed PAHs and a few were 5- or 6- ringed PAHs, which indicated less influence from industry but a high impact from the local combustion of coal and biomass; HCHs and DDTs in the profile were historically residual in this region, and HCHs mainly originated from the application of Lindane, while DDTs originated from the application of dicofol and technical DDTs; no significant correlation between the concentrations of OCPs and PAHs and the sedimental particle size in the sediments was found.

Characterization and source identification of PM2.5-bound polycyclic aromatic hydrocarbons in urban, suburban, and rural ambient air, central China during summer harvest.

Characterization and source identification of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) are conducted in urban Wuhan (WH), suburban Pingdingshan (PDS), and rural Suizhou (SZ) in China during summer harvest. This study analyzes 16 priority PAHs with 38 PM.2.5 samples in June. PAHs had similar physical-chemical properties like polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), which had been listed as Priority Pollutants. The concentration and detection frequency of OCPs and PCBs were considerably lower than those of PAHs in PM2.5. Results indicate that PDS adjoining the highway has the highest PM2.5-bound PAHs. SZ possesses the lowest concentration of PAHs. Principal component analysis and multivariate linear regression model and molecular diagnostic ratio distinguish the sources. Vehicle emissions and coal combustion are extracted in three sites, while the source of PDS also includes gas combustion. SZ was affected by gas combustion and petroleum. The potential source contribution function and the concentration-weighted trajectory track the potential pollution area. The sampling places might be affected by the local sources and short distance transmission cannot be neglected. The incremental lifetime cancer risks (ILCRs) model evaluates the exposure risk of PAHs. According to the ILCR model, WH and PDS are exposed to harmful PAHs. By contrast, SZ is a substantially safe place.

Fate of PM2.5-bound PAHs in Xiangyang, central China during 2018 Chinese spring festival: Influence of fireworks burning and air-mass transport.

Variations of levels, possible source and air mass transmission were investigated for 16 USEPA priority-controlled PAHs in PM2.5 during 2018 Chinese Spring Festival (CSF) in Xiangyang City, central China which is the North-South pollutant airmass transport channel of China. Totally 37 samples were collected. Mass concentrations of Σ16PAHs for the Pre-CSF day (Pre-CSFD), during the CSF day (CSFD) and after the CSF day (Af-CSFD) are 33.78 ± 17.68 ng/m3, 22.98 ± 6.49 ng/m3, and 8.99 ± 4.44 ng/m3, respectively. High resolution samples showed that Σ16PAHs are higher in the morning (06:00-11:00) or afternoon (11:30-16:30), than those in the evening (17:00-22:00) and at night (22:30-05:30), whereas the result is reversed during the CSFD. Fireworks burning can obviously increase the mass concentration of PAHs. Air mass trajectory indicated that Xiangyang is a sink area of pollutants for northwest and southeast, and the sources of the northeast and southwest. The air mass only can be transmitted out through northeast and southwest. It is effective for improvement of air quality in Wuhan and Hunan to control fireworks emission in Henan and local areas. Fireworks burning was an important source for PAHs during CSFD, biomass, coal combustion, and traffic emission were the main sources of PAHs for Pre-CSFD and Af-CSFD periods. The health risk on the CSFD was higher than the acceptable levels, especially during the intensive fireworks burning, the risk value far exceed 1.0 × 10-4, controlling burning fireworks is required.

Study on four metal organic frameworks as cleanup adsorbents for polycyclic aromatic hydrocarbons determined by GC-MS/MS.

A new application of MOFs as adsorbents in the cleanup procedure of polycyclic aromatic hydrocarbons (PAHs) in soils was explored. Four MOFs, specifically MIL-101(Cr), MIL-125(Ti), MIL-100(Fe) and UiO-66(Zr), were synthesized and characterized. A screening study was carried out to select the best adsorbent for the purification of sixteen PAHs in complex soil extract. It is found that the nature of metal ion, pore size, surface area and surface charge affect the purification efficiencies of the various MOFs. MIL-101(Cr) was then selected because of its best purification efficiency. The effects of amount of adsorbent, cleanup solvent and cleanup time on cleanup efficiency were investigated. Under the optimum conditions, the matrix effect of the target analytes was reduced by more than 65%. The method was then combined with ultrasonic extraction and quantitation by gas chromatography with triple quadrupole mass spectrometric detection. The method allows for the determination of PAHs in soils with linear in the range of 5-5000 ng g-1 and with LODs between 50 and 420 pg g-1. The method was applied to the analysis of (spiked) soil samples, and results compared well with the established EPA method. Graphical abstract Schematic presentation of metal organic frameworks (MOF) as cleanup adsorbents for purifying polycyclic aromatic hydrocarbons in soil organic matter (SOM) and further determined by gas chromatography with triple quadrupole mass spectrometry detection (GC-MS/MS).

Polycyclic aromatic hydrocarbons (PAHs) in agricultural soils from Ningde, China: levels, sources, and human health risk assessment.

Soil-bound polycyclic aromatic hydrocarbons (PAHs) in farmland are critical to human health. The level, composition, source, and cancer risk of sixteen PAHs in agricultural soil from Ningde, China, were investigated. The results indicated that the total concentrations of 16 PAHs ranged from 77.3 to 1188 ng g-1, with a mean value of 406 ng g-1. Five-ring PAHs were found to have the highest concentrations (148 ± 133 ng g-1), followed by four-ring (120 ± 101 ng g-1), three-ring (61.9 ± 54.2 ng g-1), six-ring (44.6 ± 61.0 ng g-1), and two-ring (31.3 ± 31.0 ng g-1). Employing positive matrix factorization (PMF), four PAH sources including biomass burning (36.3%), coal combustion (35.5%), traffic emissions (16.4%), and coke source (11.8%) were identified. Incremental lifetime cancer risk (ILCR) results showed that ILCR values ranged from 7.1 × 10-4 to 1.1 × 10-3, which will cause moderate-to-high cancer risk to human health mainly via the soil ingestion and dermal contact exposure pathways. The source-oriented results indicated that coal combustion (32.7%), traffic emission (34.3%), and biomass burning (32.4%) had similar contributions to the total cancer risk. Therefore, more attention should be paid to these pyrolysis-originated sources to protect humanity from the health risk of PAHs.

Source patterns and contamination level of polycyclic aromatic hydrocarbons (PAHs) in urban and rural areas of Southern Italian soils.

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants. They have been identified as a type of carcinogenic substance and are relatively widespread in environment media such as air, water and soils, constituting a significant hazard for human health. In many parts of the world, PAHs are still found in high concentrations despite improved legislation and monitoring, and it is therefore vital defining their profiles, and assessing their potential sources. This study focused on a large region of the south of Italy, where concentration levels, profiles, possible sources and toxicity equivalent quantity (TEQ) level of sixteen PAHs were investigated. The survey included soils from five large regions of the south of Italy: 80 soil samples (0-20 cm top layer) from urban and rural locations were collected and analysed by gas chromatography-mass spectrometry. Total PAHs and individual molecular compounds from the US Environmental Protection Agency priority pollutants list were identified and measured. Results showed that 16 PAHs varied significantly in urban and rural areas, and different regions presented discordant characteristics. Urban areas presented concentrations ranging from 7.62 to 755 ng g-1 (mean = 84.85 ng g-1), whilst rural areas presented ranges from 1.87 to 11,353 ng g-1 (mean = 333 ng g-1). Large urban areas, such as Rome, Naples and Palermo, exhibited high PAHs total concentration, but high values were also found in rural areas of Campania region. Different PAHs molecular ratios were used as diagnostic fingerprinting for source identification: LWMPAHs/HWMPAHs, Fluo/(Fluo + Pyr), BaA/(BaA + Chr), Ant/(Ant + Phe) and IcdP/(IcdP + BghiP). These ratios indicated that PAHs sources in the study area were mainly of pyrogenic origin, i.e. mostly related to biomass combustion and vehicular emission. On the other hand, values in Sicilian soils seemed to indicate a petrogenic origin, possibly linked to emissions from crude oil combustion and refineries present in the region. Finally, results allowed to calculate the toxicity equivalent quantity (TEQBAP) levels for the various locations sampled, highlighting that the highest values were found in the Campania region, with 661 and 54.20 ng g-1, in rural and urban areas, respectively. These findings, which could be linked to the presence of a large solid waste incinerator plant, but also to well-documented illegal waste disposal and burning, suggest that exposure to PAH may be posing an increased risk to human health in some of the studied areas.

Trace metals in aquatic environments of a mangrove ecosystem in Nansha, Guangzhou, South China: pollution status, sources, and ecological risk assessment.

Mangrove forests are widely located along coastlines. They have been identified to be inimitable and dynamic ecosystems. This study investigated the trace metals in mangrove water and surface sediments of Nansha, Guangzhou, China. Zn (148.42 ± 247.47 µg L-1) was the most abundant metal in waters, followed by As (82.34 ± 118.95 µg L-1), Pb (22.96 ± 120.50 µg L-1), and Ni (19.42 ± 47.84 µg L-1). In sediments, the most abundant metal was Fe (27.04 ± 1.91 g kg-1), followed by Mn (1049.04 ± 364.11 mg kg-1), Zn (566.33 ± 244.37 mg kg-1), and Cr (106.9 ± 28.51 mg kg-1). Higher contents of trace metals were detected in vicinity areas of the river mouth. The results of pollution indexes, including contamination factor, enrichment factor, and geo-accumulation index, indicated the pollution of Cd, Cu, Pb, and Zn in sediments. The Spearman correlation and cluster analysis were used to evaluate the metal sources. In water, the significant correlations among Zn and water chemical parameters (Na, Mg, K, Ca, conductivity, pH, and Cl) might indicate the natural source of Zn from the seawater. Water sampling sites in estuaries and coastal areas were clustered separately, which might indicate the influences of upstream water and the seawater, respectively. In sediments, the significant relationships among Cd, Pb, and Zn concentrations were likely to imply the emissions from industries and exploitation of the Pb-Zn mine. The occurrence of Cr and Cu in sediments can be attributed to the spills of lubricants or oil. Cd in sediments could cause serious ecological risk.

Rapid preparation of methyltrimethoxy-modified magnetic mesoporous silica as an effective solid-phase extraction adsorbent.

A time-saving method was applied to synthesize methyltrimethoxy-modified magnetic mesoporous silica with or without p-toluenesulfonic acid as the catalyst for magnetic solid-phase extraction. The synthesized materials were systematically characterized. Results demonstrated that methyltrimethoxy modified magnetic mesoporous silica with p-toluenesulfonic acid as the catalyst has a relatively smaller aperture and extreme hydrophobicity (water contact angle of 135°). To evaluate the feasibility of these prepared materials as effective adsorbents, it was combined with gas chromatography and electron capture detection to determine 26 polychlorinated biphenyls in environmental water. The result revealed that methyltrimethoxy modified magnetic mesoporous silica with p-toluenesulfonic acid as the catalyst had the best extraction efficiency and recovery. Under the optimized extracted conditions, the proposed method showed good linearity within the concentration range of 5 to 200 ng/L with correlation coefficients of 0.9969 to 0.9999. The limits of detection and quantification based on signal-to-noise ratios of 3 and 10 were in the range of 0.16 to 0.91 and 0.52 to 3.0 ng/L, respectively. The polychlorinated biphenyl concentrations in environmental water samples were successfully determined using the developed method. PCB008 and PCB110 were 4.05 and 8.52 ng/L in Red-Star lake water (Hubei Province, China), respectively.

Using solar cell to phytoremediate field-scale metal polluted soil assisted by electric field.

Eucalyptus globulus were used to remediate a real scale site endangered by e-waste with electric fields supplied by solar cell and conventional storage battery. The capacity of the species to produce biomass, absorb pollutants and decontaminate metals, as well as the soil moisture of various layers under different treatments was compared. During the 3-month experiment, the output potential of solar cell influenced by weather conditions was less stable (ranging from 0 to 8.3 V) comparing with traditional power supply. Solar cell and storage battery stimulated the growth of the species from 5.92 in control to 7.21 and 7.38 kg per plant, respectively, demonstrating their similar improvement effect. Electric fields of either power source increased the metal concentrations of plant roots and shoots in equal proportions and subsequently greatly promoted the efficiency to decontaminate pollutants. Relative to the control without electric field, solar cell and storage battery treatments reduced the soil moisture of each corresponding layer and consequently, alleviated the leaching risk. At the termination of the experiment, metals tended to distribute in the surface layer under electric field assisted phytoremediation either by solar cell or storage battery. Comparing with conventional battery, solar cell has similar effect on improving remediation and mitigating leaching risk, but is less energy consuming and easier to manage, especially under real scale field. Solar cell treatment was suggested to be a suitable supplementary means to improve phytoremediation efficiency.