Ecological risk assessment of commonly used antibiotics in aquatic ecosystems along the coast of China.

The consistent input of antibiotics into aquatic environments may pose risks to various creatures and ecosystems. However, risk assessment of pharmaceuticals and personal care products (PPCPs) in aquatic environments is frequently limited by the lack of toxicity data. To investigate the risk of commonly used antibiotics to various aquatic creatures, we focused on the distribution patterns and temporal dynamics of antibiotics in the coastal estuary area of China and performed a comprehensive ecological risk assessment for four antibiotics: erythromycin (ERY), tetracycline (TCN), norfloxacin (NOR) and sulfamethoxazole (SMX). An interspecies correlation estimation (ICE)-species sensitivity distribution (SSD) combined model was applied to predict the toxicity data of untested aquatic species, and an accurate ecological risk assessment procedure was developed to evaluate the risk level of PPCPs. The results of risk quotient assessments and probabilistic risk assessments (PRAs) suggested that four objective antibiotics in the Chinese coastal estuary area were at a low risk level. These antibiotics posed a high risk in antibiotic-related global hot spots, with probabilistic risk values for ERY, NOR, SMX, and TCN of 81.33 %, 27.08 %, 21.13 %, and 15.44 %, respectively. We applied an extrapolation method to overcome the lack of toxicity data in ecological risk assessment, enhanced the ecological reality of water quality criteria derivation and reduced the uncertainty of risk assessment for antibiotics.

Distribution and transfer rules of polycyclic aromatic hydrocarbons in soil-wheat ecosystems in China.

The translocation and accumulation patterns of polycyclic aromatic hydrocarbons (PAHs) in the soil-crop system have important implications for the fate of PAHs and human health. This study summarized the concentrations of 16 priority PAHs in the soils and various parts of mature winter wheat in China, sourced from a screening of previous literature in English and Chinese databases. The study analyzes the distribution characteristics, transfer patterns, and human health risks of PAHs in sites studied in Shaanxi, Henan, and Shandong provinces. The results showed that the concentrations of Σ16 PAHs in the rhizosphere soil of wheat ranged from 10.30 to 893.68 ng/g, in descending order of Shaanxi > Henan > average > Shandong. In sites with mild to moderate contamination (200 < Σ16 PAHs < 600 ng/g; i.e., Henan and Shaanxi), the concentration of Σ16 PAHs in the roots was higher than that in the stems or the grains, while in contamination-free sites (Σ16 PAHs < 200 ng/g; i.e., Shandong), the highest concentration of Σ16 PAHs was found in the stems. Generally, the concentrations of PAHs increased in the order of roots-stems-grains. The predominant PAHs in each part of wheat were 2- or 3-ring compounds, with five- or six-ring PAHs being more prevalent in wheat from Shanghe, Shandong. The bioaccumulation factors of different wheat parts from Shaanxi and Henan were consistently smaller than 1, and low- and medium-ring (2-4 rings) PAHs had bigger bioconcentration factors than high-ring (5-6 rings) PAHs. However, the accumulation of PAHs in the aboveground parts of wheat was larger than that in the underground parts of the Shandong sites. The linear regression relationship between the octanol-water partition coefficient and root concentration factor (RCF) of PAHs reflected that low and medium-ring PAHs were more easily absorbed by wheat roots than high-ring PAHs in Shaanxi and Henan. Our assessment of the health risks of oral wheat intake in adults and children by the incremental lifetime cancer risk (ILCR) model found a potential carcinogenic risk for both age groups in each province, with higher risks in adults than in children.

Topsoil selenium (Se) under Se-rich farming in China: Current status, cropping impacts and ecological risk assessment.

Selenium (Se), as an essential microelement, can be supplied through Se-biofortified food from Se-rich soils and associated farming practices for human health, while it can also cause eco-risks if overapplied. In this study, a multi-scale spatiotemporal meta-analysis was conducted to guide sustainable Se-rich farming in China by combining a long-term survey with a reviewed database. The weighted mean concentration, spatial distribution of soil Se, nationwide topsoil Se variation from cropping impacts and its bioavailability-based ecological risks were assessed and quantified. The results showed that the weighted mean content (0.3 mg kg-1) of China was slightly higher than that of previous nationwide topsoil Se surveys, as more Se-rich areas were found in recent high-density sampling surveys. Cropping has overall reduced Se content by 9.5% from farmland across China and deprived more with the increase in farming rotation driven by geo-climatic conditions. Long-term cropping removed Se from Se-rich areas but accumulated it in Se-deficient areas. Additionally, the bioavailable Se content of topsoil in China ranged from 0 to 332 µg kg-1, and the bioavailability-based eco-risks indicated that high eco-risks only existed in overfertilized and extremely high-Se soils, such as in Enshi, Ziyang and some coalfield areas. This work provides evidence for the development of sustainable Se-rich farming with proper utilization of soil Se resources, simultaneously protecting the soil eco-environment.

A prospective ecological risk assessment method based on exposure and ecological scenarios (ERA-EES) to determine soil ecological risks around metal mining areas.

Soil heavy metal (HM) contamination around metal mining areas (MMAs) is a global concern that requires a cost-effective ecological risk assessment (ERA) method for preventive management. Traditional ERAs, comparing environmental HM concentrations with benchmarks, are labor- and cost-intensive in field investigations and chemical analyses, which challenge the management demands of numerous MMAs. In this study, a prospective ecological risk assessment method based on exposure and ecological scenario (ERA-EES) was developed to predict the eco-risk levels (low/medium/high) around MMAs prior to field sampling. Five exposure scenario indicators related to soil HM exposure and three ecological scenario indicators reflecting the soil bioreceptor response were selected and combined with the analytic hierarchy process and fuzzy comprehensive evaluation methods for ERA-EES development. Case application and performance evaluation with 67 MMAs in China demonstrated that the ERA-EES method had an overall effective and conservative performance when referring to potential ecological risk index (PERI) levels, with an accuracy of 0.87, kappa coefficient of 0.7, and low or medium eco-risk levels in PERI classified to high levels in ERA-EES. Overall, the selected scenario indicators could efficiently reflect the risk levels of soil HM pollution from mining activities. Besides, more regulatory efforts should be paid to the MMAs of nonferrous metals, underground and long-term mining and those located in southern China. This work provided a convenient and cost-effective prospective ERA method under the trend of ERA being tiered and refined, facilitating the risk management of various MMAs.

The past 40 years' assessment of urban-rural differences in Benzo[a]pyrene contamination and human health risk in coastal China.

China has implemented many environmental regulations to battle against polycyclic aromatic hydrocarbon (PAH) contamination since the 1990s. It remains unclear how the exposure levels of PAHs changed quantitatively since reform and opening up in 1978 in China, whether the human health risks decreased or not, and how about the discrepancy between urban and rural areas. Here, taking Benzo[a]pyrene (BaP) in the rapidly urbanized Bohai region of China as a case, we used the improved Berkeley-Trent-Urban-Rural model to simulate the multimedia concentrations of BaP from 1980 to 2020 based on BaP emissions at a regional scale. The total emission of BaP in 1990 was the highest, with a value of 240 t, while the urban emission peaked in 2010. The BaP emissions from rural areas were two to seven times higher than urban areas, and the differences became smaller over time. Despite this, the average modeled BaP concentrations in urban air and soil were two to tens fold higher than in rural areas, particularly in highly urbanized or industrialized cities. Mostly, the concentrations of BaP in rural areas peaked in 1990, while those in urban areas peaked in 1990 or 2010. Early urbanized Beijing and Tianjin were the hot-spot cities of BaP contamination before 2000, while after 2010, higher concentrations were found in late industrialized Shandong and Hebei. BaP posed potential cancer risks to local residents, and air inhalation accounted for more than 80 % of the total risk. Under the stronger implementation of environmental regulations since the 1990s, it showed great health benefits, particularly for the urban residents in Beijing and Tianjin. The biggest decline in cancer risk was found in the period 2010-2020, and the average decreasing rates were 61.4 % and 57.4 % for urban and rural areas, respectively.

Ecological Responses of Soil Microbial Communities to Heavy Metal Stress in a Coal-Based Industrial Region in China.

Soil microorganisms play vital roles in ecosystem functions, and soil microbial communities might be affected by heavy metal contamination caused by the anthropogenic activities associated with the coal-based industry. This study explored the effects of heavy metal contamination on soil bacterial and fungal communities surrounding different coal-based industrial fields (the coal mining industry, coal preparation industry, coal-based chemical industry, and coal-fired power industry) in Shanxi province, North China. Moreover, soil samples from farmland and parks away from all the industrial plants were collected as references. The results showed that the concentrations of most heavy metals were greater than the local background values, particularly for arsenic (As), lead (Pb), cadmium (Cd), and mercury (Hg). There were significant differences in soil cellulase and alkaline phosphatase activities among sampling fields. The composition, diversity, and abundance of soil microbial communities among all sampling fields were significantly different, particularly for the fungal community. Actinobacteria, Proteobacteria, Chloroflexi, and Acidobacteria were the predominant bacterial phyla, while Ascomycota, Mortierellomycota, and Basidiomycota dominated the studied fungal community in this coal-based industrially intensive region. A redundancy analysis, variance partitioning analysis, and Spearman correlation analysis revealed that the soil microbial community structure was significantly affected by Cd, total carbon, total nitrogen, and alkaline phosphatase activity. This study profiles the basic features of the soil physicochemical properties, the multiple heavy metal concentrations, and the microbial communities in a coal-based industrial region in North China.

Metabolic variation and oxidative stress response of blue mussels (Mytilus sp.) perturbed by norfloxacin exposure.

Antibiotics are currently widely applied in agricultural cultivation, animal husbandry, and medical treatment, but the effects and ecological risks of antibiotics need to be further investigated. Norfloxacin is one of the most widely applied fluoroquinolone antibiotics and is commonly detected in aquatic ecosystems. In this study, the activities of catalase (CAT) and glutathione S-transferase (GST) in blue mussels (Mytilus sp.) exposed to norfloxacin (from 25 to 200 mg/L) for 2 d of acute exposure and 7 d of subacute exposure were measured. 1H nuclear magnetic resonance (1H-NMR)-based metabolomics was applied to identify the metabolites and to investigate the physiological metabolism of blue mussels (Mytilus sp.) under different concentrations of norfloxacin. The activity of the CAT enzyme was induced in acute exposure, while the activity of GST was inhibited in subacute exposure when the concentration of norfloxacin reached 200 mg/L. Orthogonal partial least squares discriminant analysis (OPLS-DA) revealed that the increased concentrations of norfloxacin might cause greater metabolic differences between the treatment and control groups and cause greater metabolic variation within the same treatment group. The contents of taurine in the 150 mg/L acute exposure group were 5.17 times higher than those in the control group. The pathway analysis indicated that exposure to high concentrations of norfloxacin disturbed different pathways involved in energy metabolism, amino acid metabolism, neuroregulation, and the regulation of osmotic pressure. These results may provide a molecular and metabolic view of the effects of norfloxacin and the regulatory mechanism of blue mussels when exposed to extremely high doses of antibiotics.

Factors influencing teachers' satisfaction and performance with online teaching in universities during the COVID-19.

The COVID-19 pandemic has significantly changed the teaching model, promoting educational institutions to initiate more explorations in online teaching. This study examines the factors influencing teachers' online teaching performance and satisfaction in universities during the COVID-19. We applied a model of technology acceptance (TAM), expectation confirmation (ECM), and computer self-efficacy (CSE) to develop a questionnaire. The survey was used to collect data from 347 teachers from 6 universities in eastern China to identify factors affecting teachers' performance and satisfaction during the COVID-19. The results indicated that teachers' performance of online teaching is significantly affected by satisfaction, perceived usefulness, and perceived ease of use of online teaching. Meanwhile, confirmation of online teaching expectations and computer self-efficacy significantly impacted teachers' satisfaction with online teaching. This work is an original empirical study guided by multiple theories. It contributes to the online education literature and provides advice regarding how teachers' online teaching satisfaction and performance can be developed in a situation like the one that occurred with COVID-19. This work also broadens the application of TAM and provides an alternative theoretical framework for future research on teachers' online teaching performance.

Multiple pollutants stress the coastal ecosystem with climate and anthropogenic drivers.

Coastal ecosystem health is of vital importance to human well-being. Field investigations of major pollutants along the whole coast of China were carried out to explore associations between coastal development activities and pollutant inputs. Measurements of target pollutants such as PFAAs and PAHs uncovered notable levels in small estuary rivers. The Yangtze River was identified to deliver the highest loads of these pollutants to the seas as a divide for the spatial distribution of pollutant compositions. Soil concentrations of the volatile and semi-volatile pollutants showed a cold-trapping effect in pace with increasing latitudinal gradient. The coastal ecosystem is facing high ecological risks from metal pollution, especially copper (Cu) and zinc (Zn), while priority pollutants of high risks vary for different kinds of protected species, and the ecological risks were influenced by both climate and physicochemical properties of environmental matrices, which should be emphasized to protect and restore coastal ecosystem functioning.

Optimized cross-correlation method for Brillouin frequency shift estimation in Brillouin scattering-based sensors.

The cross-correlation method has a low computational burden and is less sensitive to noise, but the method may have a long spectra measurement time, especially for Brillouin spectra with an asymmetric frequency sweep span. To improve the real-time performance of spectra measurement, the influence of the frequency sweep span, sweep span deviation, and frequency step on the error in the estimated Brillouin frequency shift (BFS) is systematically investigated. Based on the results, the optimal sweep span and its influencing factors are investigated. The results reveal that when the frequency sweep span is not wide enough and there is a sweep span deviation, the BFS error will not decrease with a decreasing frequency step. The error decreases rapidly with an increasing frequency sweep span, and then it tends to a stable value. The linewidth and sweep span deviation have an important effect on the optimal sweep span. An estimation formula for the optimal sweep span is presented, and an improved cross-correlation method is proposed based on it. The proposed method is compared with existing classic cross-correlation methods. The results reveal that the proposed method can ensure high BFS accuracy and decrease measurement time.

Cross-species extrapolation of chemical sensitivity.

Ecosystems are usually populated by many species. Each of these species carries the potential to show a different sensitivity towards all of the numerous chemical compounds that can be present in their environment. Since experimentally testing all possible species-chemical combinations is impossible, the ecological risk assessment of chemicals largely depends on cross-species extrapolation approaches. This review overviews currently existing cross-species extrapolation methodologies, and discusses i) how species sensitivity could be described, ii) which predictors might be useful for explaining differences in species sensitivity, and iii) which statistical considerations are important. We argue that risk assessment can benefit most from modelling approaches when sensitivity is described based on ecologically relevant and robust effects. Additionally, specific attention should be paid to heterogeneity of the training data (e.g. exposure duration, pH, temperature), since this strongly influences the reliability of the resulting models. Regarding which predictors are useful for explaining differences in species sensitivity, we review interspecies-correlation, relatedness-based, traits-based, and genomic-based extrapolation methods, describing the amount of mechanistic information the predictors contain, the amount of input data the models require, and the extent to which the different methods provide protection for ecological entities. We develop a conceptual framework, incorporating the strengths of each of the methods described. Finally, the discussion of statistical considerations reveals that regardless of the method used, statistically significant models can be found, although the usefulness, applicability, and understanding of these models varies considerably. We therefore recommend publication of scientific code along with scientific studies to simultaneously clarify modelling choices and enable elaboration on existing work. In general, this review specifies the data requirements of different cross-species extrapolation methods, aiming to make regulators and publishers more aware that access to raw- and meta-data needs to be improved to make future cross-species extrapolation efforts successful, enabling their integration into the regulatory environment.

Icon Familiarity Affects the Performance of Complex Cognitive Tasks.

The purpose of this study was to investigate whether and how users' familiarity with symbols affects the performance of complex cognitive tasks which place considerable demands on working memory resources. We combined a modified math task paradigm with our previous icon familiarity training paradigm. Participants were required to complete a mathematical task involving icons to test their ability to perform complex cognitive tasks. The complexity of the task was manipulated using three independent variables: icon familiarity (high-frequency vs. low-frequency), whether or not the equation requires substitution (substitution vs. no-substitution), and the number of steps required for solution (one step vs. two steps). The results showed that participants performed better on the equation-solving task when it used icons they were more extensively trained on. Importantly, icon familiarity interacted with the complexity of the task and the familiarity effect on performance (accuracy and response time) became greater when the complexity increased. These findings provide evidence that familiarity affects not only the ease of information retrieval but also the ease of subsequent processing activities associated with these information, which extends our understanding of how familiarity affects working memory. Moreover, our findings have practical implications for improving interaction efficiency. Before the operators formally use a digital system, they need to learn the precise meaning of those complex or unfamiliar symbols in a certain context as much as possible.

Antioxidant defenses and metabolic responses of blue mussels (Mytilus edulis) exposed to various concentrations of erythromycin.

Erythromycin, one of the most widely used macrolide antibiotics, has been detected in various aquatic environments, so erythromycin ecotoxicity should deserve more attention. In this study, blue mussels (Mytilus edulis) were exposed to erythromycin to explore its potential physiological toxicity. After 2d acute and 7d sub-acute exposure to erythromycin, blue mussel glutathione S-transferase (GST) and catalase (CAT) activities were determined with microplate methods and metabolic responses were analyzed using 1H nuclear magnetic resonance (1H NMR). The results revealed that GST was approximately 1.6 times higher in exposed mussels at 200 mg/L and higher concentrations. CAT was about 1.9 times higher in exposed mussels at 200 mg/L, indicating that erythromycin exposure led that blue mussels enhanced antioxidant responses. Low doses of erythromycin exposure had a relatively small impact on the metabolism, while high doses of erythromycin exposure (200 and 400 mg/L) disturbed metabolic balance. With the increase of erythromycin concentrations, the individual metabolic differences within the same treatment groups also increased. The significant increase in alanine, glutamate, taurine, glycine and betaine were observed after acute and subacute exposure. Betaine played an important role in protecting antioxidant enzyme activities through adjusting osmotic pressure. The metabolomic results also showed the modes of erythromycin acted on the energy metabolism, osmoregulation, nerve activities and amino acid metabolism. This study highlighted how metabolomics can provide a comprehensive picture of metabolic responses, although significant antioxidant and metabolic responses were observed at high exposure concentrations.

Mortality, growth and metabolic responses by 1H-NMR-based metabolomics of earthworms to sodium selenite exposure in soils.

The rapid development of selenium-enriched agriculture leads to the accumulation of selenium in the soil, which has an adverse impact on terrestrial ecosystems. In the present study, the mortality, growth inhibition rate and metabolism of earthworms were examined to investigate the toxicological effects of sodium selenite (Na2SeO3) on earthworms (Eisenia fetida) after exposuring for 14 days (d). We used 1H-NMR-based metabolomics to identify sensitive biomarkers and explored the metabolic responses of earthworms exposed to Na2SeO3. The mortality and growth inhibition rate of earthworms exposed to 70 and 90 mg/kg Na2SeO3 were significantly higher than the rate of control group. The LC50 (the median lethal concentration) of Na2SeO3 was 57.4 mg/kg in this artificial soil test of E. fetida exposed to Na2SeO3 for 14 d. However, there was no significant differences when earthworms were exposed to different concentrations of Na2SeO3. The selected metabolic markers were ATP, lactic acid, leucine, alanine, valine, glycine, glutamic acid, lysine, α-glucose and betaine. Na2SeO3 affected the metabolic level of earthworms, as the percentage of metabolic markers in the earthworm changes when exposed to different concentrations of Na2SeO3. The metabolic disturbances were greater with increasing concentrations of Na2SeO3. The differential metabolic markers were significantly changed when exposed to Na2SeO3 comparing to those in the control group, affecting the tricarboxylic acid cycle process and breaking the metabolic balance. This study showed that Na2SeO3 had toxic effect on the growth and development of earthworms. In addition, this study provided a biochemical insights for the development of selenium-enriched agriculture.

A review of multimedia transport and fate models for chemicals: Principles, features and applicability.

The frequent use of chemicals has caused ecosystems and humans to be threatened due to their discharge into the environment. Multimedia environmental fate models could provide a comprehensive picture of transport behaviour and fate for organic chemicals in multiple environmental media. They have been designed and widely used for chemical risk assessment, chemical ranking and management support, and determination of chemical bioaccumulation. This study reviewed the principles, features and applicability of recent commonly used multimedia fate models from peer-reviewed literature. Fugacity-based and concentration-based models are now widely adopted for use in chemical fate evaluation, while they are more appropriate for volatile and semi-volatile chemicals. Or the fugacity-based models can use aquivalence equilibrium criterion to cations, anions and involatile chemicals. The MAMI and SESAMe models based on activity approach are applicable to neutral and ionizable molecules. However, interactions of ionic species with other water solutes are not taken into account in these models. Additionally, they could not directionally simulate how chemicals transported form one grid to another. Future attention should be focused on the reliability of transfer behaviour and fate of ionizable chemicals, as integrating the advantages of these two kinds of models into a reconstructed one may be a better choice. In a word, environmental multimedia models have been beneficial tools for chemical control and management, risk and effect estimation, and decision supporting.

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.

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.

Integrated regional ecological risk assessment of multiple metals in the soils: A case in the region around the Bohai Sea and the Yellow Sea.

Methodology to quantify and distinguish the spatial distribution of the risks from multiple pollutants within the region was developed in this paper. An integrated quantitative risk assessment was conducted by utilizing a large amount of information available to explore spatial distribution of risk by single and multiple pollutants, and the magnitude of the overall risk from multiple pollutants based on the current concentrations of pollutants and toxicity data. Two target criteria levels - level I (NOEC/LOEC based) and level II (LC/EC/IC50 based) - were employed, and thus, the regional and sub-regional risks were evaluated according to these two levels. The risk of multiple toxic metals (As, Cd, Cr, Hg and Pb) to a terrestrial ecosystem for the region around the Bohai Sea and the Yellow Sea were evaluated as a case. The total overall ecological risks from heavy metals in the region for level I and level II were 21.73% and 12.53%, respectively. The risks were ranked in the order of Cr > As > Pb > Cd > Hg with Cr posing the greatest ecological risk, which was 61.12% for level I. The top three cities according to the level II ecological risk were Cangzhou > Lianyungang > Panjin, while the top three cities of level I ecological risk were Cangzhou > Panjin > Lianyungang. This method provides a quantitative risk assessment with multiple and clear protection levels for risk management.

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.