Population exposure to emerging perfluoroalkyl acids (PFAAs) via drinking water resources: Application of multivariate statistics and risk assessment models.

This study assessed the occurrence, origins, and potential risks of emerging perfluoroalkyl acids (PFAAs) for the first time in drinking water resources of Khyber Pakhtunkhwa, Pakistan. In total, 13 perfluoroalkyl carboxylic acids (PFCAs) with carbon (C) chains C4-C18 and 4 perfluoroalkyl sulfonates (PFSAs) with C chains C4-C10 were tested in both surface and ground drinking water samples using a high-performance liquid chromatography system (HPLC) equipped with an Agilent 6460 Triple Quadrupole liquid chromatography-mass spectrometry (LC-MS) system. The concentrations of ∑PFCAs, ∑PFSAs, and ∑PFAAs in drinking water ranged from 1.46 to 72.85, 0.30-8.03, and 1.76-80.88 ng/L, respectively. Perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), and perfluoropentanoic acid (PFPeA) were the dominant analytes in surface water followed by ground water, while the concentration of perfluorobutane sulfonate (PFBS), perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), and perfluorododecanoic acid (PFDoDA) were greater than long-chain PFOA and PFOS. The correlation statistics, which showed a strong correlation (p < 0.05) between the PFAA analytes, potentially indicated the fate of PFAAs in the area's drinking water sources, whereas the hierarchical cluster analysis (HCA) and principal component analysis (PCA) statistics identified industrial, domestic, agricultural, and commercial applications as potential point and non-point sources of PFAA contamination in the area. From risk perspectives, the overall PFAA toxicity in water resources was within the ecological health risk thresholds, where for the human population the hazard quotient (HQ) values of individual PFAAs were < 1, indicating no risk from the drinking water sources; however, the hazard index (HI) from the ∑PFAAs should not be underestimated, as it may significantly result in potential chronic toxicity to exposed adults, followed by children.

Redox mediators boost NOx reduction via trade-off electron charges using a cube-shaped (cMn@rGO) catalyst; mechanism and electrochemical study.

Gaseous pollutants like sulfur dioxide and nitrogen oxide(s) (SO2, NOx) have been increasing exponentially for the last two decades, which have had adverse effects on human health, aquatic life, and the environment. Recently, for air pollution taming, manganese/oxide (Mn/MnO) has become a very promising heterogeneous catalyst due to its environment-friendly, low-price, and remarkable catalytic abilities for toxic gases. In this work, cube-shaped Mn nanoparticles (cMn NPs) were decorated on the surface of reduced graphene oxide (rGO) by the solvothermal method. The resulting cMn@rGO composite was employed for electrochemical NOx reduction. However, the microscopic (TEM/HRTEM) and structural analysis were utilised to investigate the morphology and characteristics of the cMn@rGO composite. This electrochemical-based treatment for NOx reduction is employed by using electron shuttle or redox mediators. Here, four distinct redox mediators are used to address electrochemical obstacles, which effectively facilitate electron transportation and promoted NOx reduction on the electrode surface. These mediators not only significantly enhanced the NOx conversion into valuable products, i.e., N2 and N2O, but also made the process smooth with high performance. Among these mediators, neutral red (N.R) exhibited extraordinary potential in enhancing NOx reduction. The obtained results indicated that the remarkable catalytic performance (∼93%) of the cMn@rGO can be attributed to several factors, including the catalyst's three-dimensional architecture structure and abundant active sites. The designed catalyst (cMn@rGO) is not only cost-effective and sustainable but also exhibits excellent potential in effectively reducing NOx, which could be beneficial for large-scale NOx abatement.

Heavy metals in five commonly consumed fish species from River Swat, Pakistan, and their implications for human health using multiple risk assessment approaches.

This study analyzed the levels of heavy metals bioaccumulation in commonly consumed riverine fish species, including G. cavia, T. macrolepis, G. gotyla, S. plagiostomus, and M. armatus from River Swat in Pakistan, and quantify their potential risk to children and adults in general and fisherfolk communities using multiple pollution and risk assessment approaches. The highest metal detected by inductive coupled plasma mass spectrometry (ICP-MS) was Zn, which ranged from 49.61 to 116.83 mg/kg, followed by Fe (19.25-101.33 mg/kg) > Mn (5.25-40.35 mg/kg) > Cr (3.05-14.59 mg/kg) > Ni (4.26-11.80 mg/kg) > Al (1.59-12.25 mg/kg) > Cu (1.24-8.59 mg/kg) > Pb (0.29-1.95 mg/kg) > Co (0.08-0.46 mg/kg) > Cd (0.01-0.29 mg/kg), demonstrating consistent fluctuation with the safe recommendations of global regulatory bodies. The average bioaccumulation factor (BAF) values in the examined fish species were high (BAF > 5000) for Pb, Zn, Mn, Cu, Cr, Ni, and Cd, bioaccumulate (1000 > BAF < 5000) for Co, and probable accumulative (BAF <1000) for Fe, and Al, while the overall ∑heavy metals pollution index (MPI) values were greater than one (MPI > 1) indicating sever heavy metals toxicity in G. cavia, followed by S. plagiostomus, M. armatus, G. gotyla, and T. macrolepis. The multivariate Pearson's correlation analysis identified the correlation coefficients between heavy metal pairs (NiCr, CuCr, PbCr, AlCo, CuNi, and PbNi), the hierarchical cluster analysis (CA) determined the origin by categorizing heavy metal accumulation into Cluster-A, Cluster-B, and Cluster-C, and the principal component analysis (PCA) discerned nearby weathering, mining, industrial, municipal, and agricultural activities as the potential sources of heavy metals bioaccumulation in riverine fish. As per human risk perspective, S.plagiostomus contributed significantly to the estimated daily intake (EDI) of heavy metals, followed by G.cavia > M.armatus > G.gotyla > T.macrolepis in dependent children and adults of the fisherfolk followed by the general population. The non-carcinogenic target hazard quotient (THQ) and hazard index (HI) values for heavy metal intake through fish exposure were < 1, while the carcinogenic risk (CR) for individual metal intake and the total carcinogenic risk (TCR) for cumulative Cr, Cd, and Pb intake were within the risk threshold of 10-6-10-4, suggesting an acceptable to high non-carcinogenic and carcinogenic risk for both children and adults in the fisherfolk, followed by the general population.

Source apportionment and risk assessment of soil heavy metals around a key drinking water source area in northern China: multivariate statistical analysis approach.

With the intensive urbanization and industrialization in recent years, lots of products containing heavy metals (HMs) have brought in severe environment problems. Yuqiao Reservoir (YQR) is an important drinking water source area in Tianjin of China, and the soil environmental quality of YQR is vital for human health. The goal of this study was to identify the priority control pollutants and hotspots of HMs contamination of YQR catchment. Thus, an integrated field investigation was conducted to analyze the major elements such as As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in soils around YQR. Geoaccumulation index (Igeo), enrichment factor (EF) and potential ecological risk index (PERI) were employed to assess the contamination status of HMs. The average contents of these elements were given as follows: As 7.97 mg/kg, Cd 0.31 mg/kg, Cr 86.1 mg/kg, Cu 24.7 mg/kg, Hg 0.044 mg/kg, Ni 30.7 mg/kg, Pb 27.3 mg/kg and Zn 76.7 mg/kg. According to geoaccumulation index (Igeo) and enrichment factor (EF) values, Cd, Cr, Pb and As showed a prominent enrichment. The result of multivariate statistics showed that Cd, Cr, Cu, As, Ni, Pb and Zn concentrations were mainly affected by human activities, whereas Hg was mainly from natural release. The anthropogenic activities were the major sources with a contribution of 91.46%, while natural origins only contributed 8.54%. And agricultural fertilization, mining and traffic activities are the most probable sources of these heavy metals in the soil. The PERI values indicated that 65.7% of total HMs were at low risk, 22.5% in moderate risk and 11.8% in considerable risk. To ensure soil environmental quality and human health, cadmium should be listed as a priority control pollutant. Spatial maps of HMs and their integrated PERI provided clear hotspots that indicated lower risk in the region close to YQR but higher risk in the region far from YQR.

Heavy metal pollution in the soil of a riverine basin: distribution, source, and potential hazards.

Soil pollution with heavy metals (HMs) has become a world environmental problem. This study focuses on surface soil contamination with Cr, Mn, Co, Ni, Cu, Zn, Cd, Hg, Pb, Fe, and Al, their sources, and potential hazards along the basin of River Swat, Pakistan. The average concentrations (mg/kg) of HMs were the most abundant for Al (24,730.19) followed by Fe (22,419.41) > Mn (386.78) > Zn (57.75) > Cr (38.07) > Ni (32.46) > Cu (23.43) > Pb (19.59) > Co (10.77) > Cd (3.18) > Hg (0.12). The concentrations of Cr and Mn in 5.45% each, Co in 10.90%, Zn in 27.27%, Cu in 36.36%, Ni in 41.81%, and Hg in 92.72% of the total soil samples exceeded their respective background values. The geostatistical approaches determined the distribution patterns of HM pollution along the basin, whereas the statistics of principal component analysis exposed the likely sources of HM contamination in the area. Pollution indices evaluated the overall HM distribution and pollution status in the area. Contamination factor showed a high degree of HM contamination in 82% of the total sampling sites, while the geo-accumulation index designated low to moderate contamination with Cr, Mn, Co, Ni, Cu, Zn, Hg, and Pb, and moderate to extreme contamination with Cd, Fe, and Al. The trend of ecological toxicity showed potential ups and downs along with the sites from low to considerable hazard (< 95 < PEHI < 190), whereas the human carcinogenic hazard was within the USEPA acceptable limits (1 × 10-7-1 × 10-4), but the non-carcinogenic hazard was higher than the threshold (HI > 1) for children because they are more exposed than adults.

An integrated approach towards marble waste management: GIS, SFA, and recycling options.

Marble units generate an enormous amount of non-biodegradable waste during the processing operations and are considered one of the environmentally unfriendly industrial sectors. This sector has become a global nuisance due to its multi-dimensional damaging nature. Therefore, a multidimensional approach is needed to geographically describe the pollution sources, their waste load, collection mechanism, and their proper disposal or reuse. This article highlights an integrated approach to sorting out the multidimensional issues associated with the marble sector. More than 150 marble processing units (MPUs) are scattered in the study area pouring waste into the environment in the form of slurry. The produced waste roots environmental issues both for fauna and flora of the terrestrial and aquatic segments of the environment. A geospatial-based attempt has been made through geographic information system (GIS) for the identification and description of the pollution sources, MPUs, in the study area. The quantitative assessment has been made through substance flow analysis (SFA) by taking raw marble as the input source and marble product as output. Furthermore, material characterization has been carried out to confirm the chemical composition of the slurry waste for its potential use. Results confirmed that a major part (> 90%) of marble powder is calcium carbonate (CaCO3) which has so many potential uses as raw material. The integrated approach of GIS, SFA, and chemical characterization set forth a model that satisfies multi-dimensional queries regarding pollution sources, pollution load, and sustainable solutions to the problem. The output integrated model provides a digital environmental baseline for the monitoring of MPUs, the amount of waste generated by these MPUs, and its potential reuse options. The proposed model can be utilized worldwide as a decision support tool due to its optimum results.

Effects of land use and landscape on the occurrence and distribution of microplastics in soil, China.

Microplastic pollution in the soil environment has gathered widespread attention. However, little is known about the effects of land use and landscape patterns on the occurrence and distribution of microplastics in the soil. Herein, the microplastic pollution in different land uses (facility farmland, traditional farmland, orchard, grassland, and woodland) in Yuanmou County, Yunnan Province was investigated. The results showed that the abundance of microplastic ranged from 50.000 to 3450.0 items·kg-1, with an average abundance of 595.00 ± 740.00 items·kg-1 and a median of 375.00 items·kg-1. Microplastics were found to primarily be green-coloured (28.4 %), fragment (72.7 %) in shape, <1 mm (75.7 %) in size, and composed of polypropylene (51.4 %). There were significant differences in the abundance and characteristics of the microplastics between different land use types. Microplastic abundance in facility farmlands, traditional farmlands, and orchard lands was significantly higher than that of grasslands and woodlands (p < 0.05). The main shape of the microplastics in facility farmlands, traditional farmlands, and orchards was fragments and it was fibers in grasslands and woodlands. The median particle size of microplastics in facility farmlands (539.50 µm) and traditional farmlands (574.00 µm), was smaller than those in the orchard (737.60 µm), grasslands (697.60 µm), and woodlands (1239.4 µm). Discrepancies among different land uses may be due to various reasons, such as different pollution sources and the weathering degree of microplastics. The results of the redundancy analysis showed that the microplastic abundance was negatively correlated with the largest patch index. It also showed that microplastic pollution was closely related to human activities. This study provides an important basis for further research on microplastic ecosystem risks that are associated with land use and provides a data basis for formulating effective prevention and control strategies and measures to mitigate soil microplastic pollution.

First report of perfluoroalkyl acids (PFAAs) in the Indus Drainage System: Occurrence, source and environmental risk.

Perfluoroalkyl acids (PFAAs) are of global interest due to their persistence in the aquatic environment. This study assessed the occurrence of PFAAs in the Indus Drainage System and discerned their potential sources and environmental risks for the first time in Pakistan. 13 perfluoroalkyl carboxylic acids (PFCAs) and 4 perfluoroalkyl sulfonates (PFSAs) were analyzed to verify the dominant prevalence of short-chain PFAAs in the environment since the phase-out of long-chain perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). A significant variation (p ≤ 0.05) of individual PFAAs between the monitoring sites was confirmed by data normality tests Kolmogorov-Smirnov and Shapiro-Wilk, suggesting that different locations contribute differently to individual PFAAs concentrations. ΣPFAAs concentrations in riverine water and sediments ranged from 2.28 to 221.75 ng/L and 0.78-29.19 ng/g dw, respectively. PFBA, PFPeA, and PFHxA were the most abundant PFAAs, and on average accounted for 14.64, 13.75, and 12.97 ng/L of ∑PFAAs in riverine water and 0.34, 0.64, and 0.79 ng/g dw of ∑PFAAs in sediments. ΣPFAAs mean contamination in the drainage was significantly (p < 0.05) high in River Chenab followed by River Indus > Soan > Ravi > Kabul > Swat with more prevalence of short-chain (C4-C7) PFCAs followed by PFOA, PFBS, PFOS, PFNA, PFDA, PFHxS, PFUnDA, and PFDoDA. The correlation analysis determined the PFAAs' fate and distribution along the drainage, indicating that PFAAs with carbon chains C4-C12, except for PFSAs with carbon chains C6-C8, were most likely contaminated by the same source, the values of Kd and Koc increased linearly with the length of the perfluoroalkyl carbon chain, better understand the transport and partitioning of individual PFAAs between riverine water and sediments, where the HCA and PCA discerned industrial/municipal wastewater discharge, agricultural and surface runoff from nearby fields, and urban localities as potential sources of PFAAs contamination. The collective mass flux of short-chain (C4-C7) PFCAs was 5x higher than that of PFOS + PFOA, suggesting a continuous shift in the production and usage of fluorinated replacements for long-chain PFAAs with short-chain homologs. In terms of risk, individual PFAAs pollution in the drainage was within the world's risk thresholds for human health, with the exception of PFBA, PFPeA, PFHpA, PFHxA, PFOA, PFNA, and PFBS, whereas for ecology, the concentrations of individual PFAAs did not exceed the ecological risk thresholds of the United States of America, Canada, European Union (EU), Italy, Australia, and New Zealand, with the exception of PFSAs, whose detected individual concentrations were significantly higher than the EU, Australian and New Zealander PFSAs guidelines of 0.002 µg/L, 0.00047 µg/L, 0.00065 µg/L, 0.00013 µg/L, and 0.00023 µg/L, respectively, which may pose chronic risks to the regional ecosystem and population.

Heavy metals contamination, potential pathways and risks along the Indus Drainage System of Pakistan.

Riverine water exposed to heavy metals (HMs) pollution is a major concern in the world because of its serious effects on ecosystem and human health. This study assessed the pollution status, sources, diffusion and potential risks of Mn, Co, Cu, Zn, Cr, Ni, Cd, Hg and Pb for the first time along the entire Indus Drainage System of Pakistan. The concentrations of nine HMs in the riverine water ranged from 5.05-101.59 µg/L with a mean value of 41.51 µg/L. The overall metals quantification along the drainage was significantly high (27% of the total) in River Chenab followed by River Indus (26%) > Soan (20%) > Ravi (19%) > Kabul (5%) > Swat (3%). The potential sources of contamination were identified to be the surrounding geogenic activities, industrial/municipal wastewater discharges, agricultural and surface runoffs by using multivariate statistics including metals correlation analysis, hierarchical cluster analysis and principal component analysis. The average mass flux of ∑HMs in the entire drainage was approximately 10.24 tons/year, to which the River Indus contributed 84% of the total, Chenab 11%, Ravi 3%, Kabul 1%, and Soan 1% with more prevalence of biological essential (Zn&Mn) and non-essential (Ni&Cr) metals. In terms of ecological risk, the riverine water metals contamination (1.59 to 57.06) was within the risk threshold (ERI < 110), while the risks of ∑carcinogenic metals for exposed children and adults along the basin were significantly influenced between acceptable to high cancer risk by Cd, Co, Ni, Cr and Pb.

Antioxidant enzymes and association of CAT SNP-21 A/T (rs7943316) with male infertility.

Infertility is a multifactorial and polygenic disease. A vast majority of infertility is still unexplained despite modern diagnostic techniques. Oxidative stress is considered a factor for male infertility but etiology in terms of functional gene polymorphism and experimental studies on human subjects is scarcely reported. The aim of the study was to investigate the status of three antioxidant enzymes; catalase, superoxide dismutase (SOD), and glutathione reduced (GSH) in clinically diagnosed infertile males and find the potential association of CAT gene variant in the promoter region -21 A/T (rs7943316). The study consisted of 55 clinically diagnosed infertile males and 50 non-infertile volunteers. The activity of antioxidant enzymes was measured through a spectrophotometer. Polymerase chain reaction-restriction fragment length polymorphism was performed for genotyping of single-nucleotide polymorphism. Catalase enzyme activity was significantly decreased while SOD and GSH were substantially increased (p ≤ 0.01) in infertile men in comparison to non-infertile. CAT gene variant rs7943316 had shown significant association in dominant, recessive model and allelic frequencies. The study concludes that rs7943316 has a substantial role in male infertility. The outcome of the study may help in resolving idiopathic infertility cases and may help in evolving novel diagnostic and therapeutic approaches. Other variants of CAT and antioxidant genes are suggested to ascertain further insight.

Bioaccumulation and human exposure of perfluoroalkyl acids (PFAAs) in vegetables from the largest vegetable production base of China.

This study investigated perfluoroalkyl acids (PFAAs) in edible parts of vegetables, soils, and irrigation water in greenhouse and open filed, for the first time, in Shouguang city, the largest vegetable production base in China, which is located nearby a fluorochemical industrial park (FIP). The bioaccumulation factors (BAFs) were calculated, and the human exposures of PFAAs via consumption of the vegetables for different age groups assuming the maximum levels detected in each vegetable and average consumption rates were also estimated. The ΣPFAA levels ranged from 1.67 to 33.5 ng/g dry weight (dw) in the edible parts of all the vegetables, with perfluorobutanoic acid (PFBA) being the dominant compound with an average contribution of 49% to the ΣPFAA level. The leafy vegetables showed higher ΣPFAA levels (average 8.76 ng/g dw) than the fruit and root vegetables. For all the vegetables, the log10 BAF values of perfluorinated carboxylic acids showed a decreasing trend with increasing chain length, with PFBA having the highest log10 BAF values (average 0.98). Cabbage had higher bioaccumulation of PFBA (log10 BAF 1.24) than other vegetables. For the greenhouse soils and vegetables, the average contribution of perfluorooctanoic acid (PFOA) to ΣPFAA was lower than that in the open field samples, while the contributions of PFBA, PFHxA, PFPeA to ΣPFAA were higher. Irrigation water may be an important source of PFAAs in greenhouse, while for open field vegetables and soils, atmospheric deposition may be an additional contamination pathway. The estimated maximum exposure to PFOA through vegetable consumption for urban preschool children (aged 2-5 years) was 63% of the reference dose set by the European Food Safety Authority. Suggestions are also provided for mitigating the health risks of human exposure to PFAAs.

Hydrogeochemistry and quality of surface water and groundwater in the drinking water source area of an urbanizing region.

The water quality in drinking water source area is essential for human health. Due to rapid urbanization and industrialization, the pollutants, especially trace elements, are continuously discharged into aquatic environment and pose a risk to human health. An extensive investigation was carried out in drinking water source area in highly urbanized Tianjin of China. Long-term monitoring data of the water body was collected on conventional physical and chemical parameters (pH, ions, TOC etc.) and metallic elements (Hg, As Cd, Pb, Co, U etc.) from 2005 to 2017. Our results showed that CaMg-Cl-SO4 and CaMg-HCO3 were the two prominent hydrochemical materials, implying that the pollution of aquatic system was mainly caused by anthropogenic activities and mineral dissolution within terms of drinking water guidelines (national and international standards), the concentrations of arsenic (As) and iron (Fe) were beyond the quality standards. Multivariate statistical approaches were applied to assess the origins of the elements. The results showed that human activities, as well as endogenous release, contributed significantly to appearance of trace elements. A transformation from low-trophic state to high-trophic state was in progress from 2005 to 2017 in Yuqiao reservoir, and most of the water was not heavily polluted by trace elements. The health risk assessment suggested that As had the potential to cause carcinogenic harm to the local residents, with daily dietary ingestion as the most predominant pathway.

Occurrence, sources and health risk of polyfluoroalkyl substances (PFASs) in soil, water and sediment from a drinking water source area.

Polyfluoroalkyl substances (PFASs) enter into environmental metric via various pathways in the process of manufacturing and consuming the products containing PFASs. Yuqiao reservoir (YQR) is a major drinking water source in Tianjin of China, where little attention was given to PFASs. To explore the occurrence, source and risk of 17 PFASs, multi-media environmental including soil, water, and sediment were sampled from this water source area. The ∑PFASs concentrations of surface water, groundwater, soil and sediment ranged from 5.839 to 120.885 ng/L, 1.426 to 17.138 ng/L, 0.622 to 5.089 µg/kg dw, and 0.240 to 1.210 µg/kg dw respectively. Some short-chained (C4-C8) PFASs were detected widely such as PFOA, PFBA, PFHxA, PFBS, PFHpA and PFPeA in surface water and groundwater, with the detection frequency of ＞78%, and PFBA and PFOA dominated in the 17 PFASs. In addition, the correlations between total PFASs and TOC were significant at 0.05 level, especially in surface water with R2 = 0.9165 (p = 0.011). In terms of vertical distribution characteristics of ∑PFASs, the ∑PFASs in four sediment cores showed a decreasing trend at first, and then an increasing trend from the bottom to the top associated with TOC. PFBA/PFOA and PFHpA/PFOA showed better linear correlations with R2 of 0.5541 (p = 0.039), and for PFNA/PFOA and PFHpA/PFOA with R2 of 0.6312 (p = 0.032) at the 0.05 level in the surface water, which indicated that sewage and atmospheric precipitation were the major sources. Though the RQ results based on the measured concentrations and reference values in environmental media revealed lower risks, the potential hazard may occur due to accumulation characteristics and long-distance transmission capability of PFASs. Hence, the corresponding management strategies should be taken, such as control over emission at source, product substitution and strengthening legislation, to eliminate potential risks to human health.

Simulating transport, flux, and ecological risk of perfluorooctanoate in a river affected by a major fluorochemical manufacturer in northern China.

Perfluoroalkyl acids (PFAAs) have been widely detected and pose potential risks to both human and ecosystem health. Since the probation of perfluorooctane sulfonate (PFOS) by the Stockholm Convention, perfluorooctanoate (PFOA) has frequently been used as a chemical intermediate and processing aid. Owing to a lack of effective treatment technologies for PFOA, surrounding environments have been highly affected. Previous studies by our group have reported elevated PFOA levels in the Xiaoqing River, which receives sewage from a major fluorochemical manufacturer in northern China. To further explore the transport, flux, and ecological risk of the perfluorooctanoate in the river, this study conducted a 2-year sampling campaign of surface water from 2014 to 2015. An extremely high PFOA concentration (mean: 62.3 µg L-1) was observed for the Xiaoqing River in comparison with other studies. The highest average concentration and flux of PFOA were recorded in the autumn and summer, respectively. With data on selected hydrological parameters and cross-sections, PFOA concentrations were modeled using DHI MIKE 11. To explore the current loads and environmental capacity of PFOA, two scenarios (i.e., emissions based on observed concentrations and on the predicted no-effects concentration, PNEC) were set. The simulation results based on observed data showed that PFOA loads in the Xiaoqing River were 11.4 t in 2014, and 12.5 t in 2015. Based on the PNEC, the environmental carrying capacity of PFOA was estimated to be 13.9 t in 2014, and 13.8 t in 2015. The current loads of PFOA were found to approach the maximum environmental carrying capacity. Relatively high risks around both the fluorine industrial park (FIP) and estuary area were identified. In comparison with other suggested guidelines, threats to the ecological status of the river would be severe, which suggests that stringent management and emission criteria are needed for this industry.

Climate change induced eutrophication of cold-water lake in an ecologically fragile nature reserve.

Aquatic ecosystem sustainability around the globe is facing crucial challenges because of increasing anthropogenic and natural disturbances. In this study, the Tianchi Lake, a typical cold-water lake and a UNESCO/MAB (Man and Biosphere) nature reserve located in high latitude and elevation with the relatively low intensity of human activity was chosen as a system to examine the linkages between climate change and eutrophication. As a part of the UNESCO Bogda Man and Biosphere Reserve, Tianchi Lake has been well preserved for prevention from human intervention, but why has it been infected with eutrophication recent years? Our results show that climate change played a significant role in the eutrophication in the Tianchi Lake. Increased temperature, changed precipitation pattern and wind-induced hydrodynamic fluctuations in the summer season were suggested to make a major contribution to the accelerated eutrophication. The results also showed that the local temperature and precipitation changes were closely linked to the large-scale atmospheric circulation, which opens the door for the method to be applied in other regions without local climatic information. This study suggests that there is an urgent need to take into consideration of climate change adaptation into the conservation and management of cold-water lakes globally.

NO Removal with Efficient Recovery of N2O by Using Recyclable Fe3O4@EDTA@Fe(II) Complex: A Novel Approach toward Resource Recovery from Flue Gas.

Traditional technologies for handling nitrogen oxides (NO x) from flue gas commonly entail the formation of harmless nitrogen gas (N2), while less effort has been made to recover the N-containing chemicals produced. In this work, we developed a novel nanomagnetic adsorbent, Fe3O4@EDTA@Fe(II) (MEFe(II)), for NO removal. The NO adsorbed by MEFe(II) was then selectively converted to N2O, a valuable compound in many industries, by using sulfite (a product from desulfurization in flue gas treatment) as the reductant for the regeneration of MEFe(II). Because of the magnetic and solid properties of MEFe(II), the processes of NO adsorption and N2O recovery can be readily carried out under their optimal pH conditions in separate systems. In addition, the produced N2O is easily handled without unwanted release to the atmosphere. At the optimal pH (7.5 and 8.0 for NO adsorption and N2O recovery, respectively), the maximum NO adsorption capacity of MEFe(II) was measured as 0.303 ± 0.037 mmol·g-1, over 90% of which was converted to N2O during the recovery process. Moreover, MEFe(II) exhibited good five consecutive cycles. All of above reactions were performed at room temperature. These findings indicate MEFe(II) may hold great potential for application to NO removal from flue gas with the benefits of resource recovery, decreased chemical use, and low energy consumption.

Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan.

Fecal bacteria contaminate water resources and result in associated waterborne diseases. This study assessed drinking water quality and evaluated their potential health risks in Swat, Pakistan. Ground and surface drinking water were randomly collected from upstream to downstream in the River Swat watershed and analyzed for fecal contamination using fecal indicator bacteria (Escherichia coli) and physiochemical parameters (potential of hydrogen, turbidity, temperature, electrical conductivity, total dissolved solid, color, odor and taste). The physiochemical parameters were within their safe limits except in a few locations, whereas, the fecal contaminations in drinking water resources exceeded the drinking water quality standards of Pakistan Environmental Protection Agency (Pak-EPA), 2008 and World Health Organization (WHO), 2011. Multivariate and univariate analyses revealed that downstream urbanization trend, minimum distance between water sources and pit latrines/sewerage systems, raw sewage deep well injection and amplified urban, pastures and agricultural runoffs having human and animal excreta were the possible sources of contamination. The questionnaire survey revealed that majority of the local people using 10-20years old drinking water supply schemes at the rate of 73% well supply, 13% hand pump supply, 11% spring supply and 3% river/streams supply, which spreads high prevalence of water borne diseases including hepatitis, intestinal infections and diarrhea, dysentery, cholera, typhoid fever, jaundice and skin diseases in children followed by older and younger adults.

Plastic waste as a significant threat to environment - a systematic literature review.

Context Materials which exceed the balance of their production and destruction lead to the deterioration in the environment. Plastic is one such material which poses a big threat to the environment. A huge amount of plastic is produced and dumped into the environment which does not readily degrade naturally. In this paper, we address the organization of a large body of literature published on the management of waste plastics being the most challenging issue of the modern world. Objectives To address the issue of the management of waste plastics, there is a dire need to organize the literature published in this field. This paper presents a systematic literature review on plastic waste, its fate and biodegradation in the environment. The objective is to make conclusions on possible practical techniques to lessen the effects of plastic waste on the environment. Method A systematic literature review protocol was followed for conducting the present study [Kitchenham B, Brereton OP, Budgen D, Turner M, Bailey J, Linkman S. Systematic literature reviews in software engineering - A systematic literature review. Inf Softw Technol 2009;51(1):7-15.]. A predefined set of book sections, conference proceedings and high-quality journal publications during the years 1999 to September 2017 were used for data collection. Results One hundred and fifty-three primary studies are selected, based on predefined exclusion, inclusion and quality criteria. These studies will help to identify the fate of different waste plastics, their impact and management and the disposal techniques frequently used. The study also identifies a number of significant techniques and measures for the conversion of waste plastic materials into useful products. Conclusion Five fundamental strategies are used for the handling of plastic waste. These strategies include: recycling, depositing in landfill, incineration, microbial degradation and conversion into useful materials. All of these methods have their own limitations, due to which there is need to explore the studies for optimum solutions of the management of plastics waste.

Multimedia fate and transport simulation of perfluorooctanoic acid/ perfluorooctanoate in an urbanizing area.

Strong global demand leads to significant production of fluoropolymers (FP) in China which potentially release large quantities of perfluorooctanoic acid/perfluorooctanoate (collectively called PFOA/PFO) to the environment. Modelling the fate and transport of PFOA/PFO provides an important input for human health risk assessment. Considering the effects of urbanization and existing forms of PFOA/PFO, this study used the modified multispecies Berkeley-Trent-Urban-Rural model to simulate the transfer behavior of PFOA/PFO in the Bohai Rim, China. Spatial distributions of PFOA/PFO emissions during the year 2012 for the study area were illustrated. About two thirds of the total amount of PFOA/PFO was estimated to be released into fresh water, and the total releases to rural areas were 160-fold higher than those to urban areas due to the location of fluorochemical industrial parks. The simulations predicted that hydrosphere was the fate of PFOA/PFO, followed by soil and vegetation, which was consistent with field data. The highest PFOA/PFO concentration was modeled in the Xiaoqing River basin with a value of 32.57 µg/L. The PFOA/PFO concentrations in urban soils were generally higher than those in rural soils except for grids 1, 3 and 46. In addition, it was estimated that the total flux of PFOA/PFO entering into the Bohai Sea was 24.57 ton/year, 100-fold higher than that of perfluorooctane sulfonates (PFOS).

Toxicological effects on earthworms (Eisenia fetida) exposed to sub-lethal concentrations of BDE-47 and BDE-209 from a metabolic point.

Earthworms improve the soil fertility and they are also sensitive to soil contaminants. Earthworms (Eisenia fetida), standard reference species, were usually chosen to culture and handle for toxicity tests. Metabolic responses in earthworms exposed to 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) and decabromodiphenyl ether (BDE-209) were inhibitory and interfered with basal metabolism. In this study, 1H-NMR based metabolomics was used to identify sensitive biomarkers and explore metabolic responses of earthworms under sub-lethal BDE-47 and BDE-209 concentrations for 14 days. The results revealed that lactate was accumulated in earthworms exposed to BDE-47 and BDE-209. Glutamate increased significantly when the concentration of BDE-47 and BDE-209 reached 10 mg/kg. The BDE-47 exposure above 50 mg/kg concentration decreased the content of fumarate significantly, which was noticed different from that of BDE-209. Whereas, the BDE-207 or BDE-209 exposure increased the protein degradation into amino acids in vivo. The increased betaine content indicated that earthworms may maintain the cell osmotic pressure and protected enzyme activity by metabolic regulation. Moreover, the BDE-47 and BDE-209 exposure at 10 mg/kg changed most of the metabolites significantly, indicating that the metabolic responses were more sensitive than growth inhibition and gene expression. The metabolomics results revealed the toxic modes of BDE-47 and BDE-209 act on the osmoregulation, energy metabolism, nerve activities, tricarboxylic acid cycle and amino acids metabolism. Furthermore, our results highlighted that the 1H-NMR based metabolomics is a strong tool for identifying sensitive biomarkers and eco-toxicological assessment.