High-risk Pollutants Research Articles

Priority Organic Pollutant Monitoring Inventory and Relative Risk Reduction Potential for Solid Waste Incineration.

Incineration is a promising sustainable treatment method for solid waste. However, the ongoing revelation of new toxic pollutants in this process has become a controversial issue impeding its development. Thus, identifying and regulating high-risk pollutants emerge as pivotal strides toward reconciling this debate. In this study, we proposed a workflow aimed at establishing priority monitoring inventories for organic compounds emitted by industries involving full-component structural recognition, environmental behavior prediction, and emission risk assessment, specifically focusing on solid waste incineration (SWI). A total of 174 stack gas samples from 29 incinerators were first collected. Nontarget full organic recognition technology was then deployed to analyze these samples, and 646 organic compounds were identified. The characteristics, i.e., toxicity effects, toxicity concentrations, persistence, and bioaccumulation potential, of these compounds were assessed and ranked based on the TOXCAST database from the US Environmental Protection Agency and structural effect models. Combined with consideration of changes in seasons and waste types, a priority control inventory consisting of 28 organic pollutants was finally proposed. The risks associated with SWI across different regions in China and various countries were assessed, and results pinpointed that by controlling the priority pollutants, the average global emission risk attributed to SWI was anticipated to be reduced by 71.4%. These findings offer significant guidance for decision-making in industrial pollutant management, emphasizing the importance of targeted regulation and monitoring to enhance the sustainability and safety of incineration processes.

Evidence for high-risk pollutants and emerging microbial contaminants at two major bathing ghats of the river Ganga using high-resolution mass spectrometry and metagenomics

An efficient wastewater treatment plant is imperative to limit the entry of emerging pollutants (EPs) and emerging microbial contaminants (EMCs) in the river ecosystem. The detection of emerging EPs in aquatic environments is challenging due to complex sample preparation methods, and the need for sophisticated accurate analytical tools. In Varanasi (India), the river Ganga holds immense significance as a holy river but is consistently polluted with municipal (MWW) and hospital wastewater (HWW). We developed an efficient method for untargeted detection of EPs in the water samples using High-resolution mass spectrometry (HRMS), and identified 577 and 670 chemicals (or chemical components) in the water samples from two major bathing ghats, Assi Ghat (AG) and Dashashwamedh Ghat (DG), respectively. The presence of EPs of different categories viz chemicals from research labs, diagnostic labs, lifestyle and industrial chemicals, toxins, flavor and food additives indicated the unsafe disposal of MWW and HWW or inefficient wastewater treatment plants (WWTPs). Besides, shotgun metagenomic analysis depicted the presence of bacteria associated with MWW viz Cloacibacterium normanse, Sphaerotilus natans (sewage fungi), E. coli, and Prevotella. Also, the presence of human pathogens Arcobacter, Polynucleobacter, Pseudomonas, Klebsiella, Aeromonas, Acinetobacter, Vibrio, and Campylobacter suggests the discharge of HWW. EPs are linked to the development, and transmission of antimicrobial resistance (AMR). Occurrence of antibiotic resistance genes (ARGs), plasmid-borne β-lactamases, aminoglycoside transferases, and ARGs associated with integrons, transposons and plasmids viz mcr-3 gene that confer resistance to colistin, the last resort of antibiotics confirmed the presence of emerging microbial contaminants. Subsequent genome reconstruction studies showed the presence of uncultivable ARB and transmission of ARGs through horizontal gene transfer. This study can be used to monitor the health of aquatic bodies as well as the efficiency of WWTPs and raise an urgent need for efficient WWTPs to safeguard the river, Ganga.

Identification of Omitted Pollutants in Environmental Water via In Situ Thin-Film Microextraction.

Sample preparation is an inevitable step in the screening workflow for the identification of unknown pollutants in the aquatic environment. However, the possible loss of pollutants during sample preparation has aroused serious concern but remains not effectively resolved. This study shows that high-risk pollutants omitted in solid-phase extraction (SPE) can be identified via in situ thin-film microextraction (TFME) coupled with high-resolution mass spectrometry. It was observed that a total of 541 features showed higher mass spectrometry signal intensity by using in situ TFME in comparison with SPE. Subsequently, 28 compounds were identified from the features with higher intensity by comparing the recorded tandem mass spectra with the online database and validating with standards. Notably, six out of these compounds were completely omitted using SPE, including a dye, drug, and industrial product. It was confirmed that the lower extraction efficiencies of SPE were attributed to the limited sample volumes, the losses of compounds during sample transportation and storage, and the entrapment of compounds in SPE columns. This study demonstrates that in situ TFME should be used as a supplementary technique to SPE for extending the coverage of pollutants in the screening workflows.

Screening of Characteristic Pollutants and Risk Pollutants in Different Media in the Yangtze River Basin Using Comprehensive Evaluation and Risk Quotient Methods

A variety of pollutants have frequently been detected in the Yangtze River Basin with the rapid economic development, the population increase, and the acceleration of urbanization, which threaten the aquatic ecosystem and human health. A multi-criteria comprehensive evaluation method was developed to identify the characteristic pollutants, and the risk quotient method was used to derive the risk pollutants in water and sediment samples in this article. A total of 155 pollutants from 11 categories were detected in the Yangtze River Basin according to the literature research. Then, the K-means method was used to analyze the cluster of pollutant comprehensive scores. All pollutants were graded based on their scores and recorded as Ⅰ-Ⅵ according to the number of cases in each cluster. A total of 43 pollutants with high scores of Ⅰ and Ⅱ were listed as the characteristic pollutants, which included 11 polycyclic aromatic hydrocarbons, 11 organochlorine pesticides, 10 polychlorinated biphenyls, eight dioxins, two heavy metals, and one phthalate ester. The top five median concentrations of contaminants in water and sediment samples were heavy metals, polycyclic aromatic hydrocarbons, phthalates esters, bisphenols, and pharmaceuticals and personal care products. According to the principle of risk maximization, the risk entropy value （RQ） was calculated based on the highest pollutant concentration. A total of 38 risky pollutants were screened in the water samples （RQ ≥ 0.1）. There were eight high-risk pollutants with RQ ≥ 1, which included benzo[a,h]-anthracene, anthracene, benzo[a]anthracene, pyrene, methoxychlor, aldrin, 2,4'-dichlorodiphenyl, and cadmium. There were 15 high-risk contaminants in the sediment, which included benzo[b]fluoranthene, anthracene, acenaphthene, fluoranthene, cadmium, lead, chromium, arsenic, selenium, dibutyl phthalate, dimethyl phthalate, diisobutyl phthalate, norfloxacin, perfluorobutyric acid, and bisphenol A. The risk pollutants contained emerging pollutants, which included ten pollutants in water samples and nine pollutants in sediments. Antibiotic pollutants accounted for the largest proportion of these emerging pollutants. The information provided in this article may be useful for the relevant departments to monitor the pollutants and propose management programs for the Yangtze River Basin. Additionally, it is of great significance for the ecological environmental protection and management of the Yangtze River Basin.

Toxicity prediction and risk assessment of per- and polyfluoroalkyl substances for threatened and endangered fishes

Per- and polyfluoroalkyl substances (PFASs) are severely polluted in aquatic environments and can harm aquatic organisms. Due to the limitation of conducting toxicity experiments directly on threatened and endangered (T&E) species, their toxicity data is scarce, hindering accurate risk assessments. The development of computational toxicology makes it possible to assess the risk of pollutants to T&E fishes. This study innovatively combined machine learning models, including random forest (RF), artificial neural network (ANN), and XGBoost, and the QSAR-ICE model to predict chronic developmental toxicity data of PFASs to T&E fishes. Among these, the XGBoost model exhibited superior performance, with R2 of 0.95 and 0.81 for the training and testing sets, respectively. Internal and external validation further confirmed that the XGBoost model is robust and reliable. Subsequently, it was used to predict chronic developmental toxicity data for seven priority PFASs to T&E fishes in the Yangtze River. Acipenseridae fishes (e.g., Acipenser dabryanus and Acipenser sinensis) showed high sensitivity to PFASs, possibly due to their unique lifestyle and physiological characteristics. Based on these data, the predicted no-effect concentration (PNEC) of individual PFASs was calculated, and the risk for T&E fishes in the Yangtze River was assessed. The results indicated that the risk of PFASs to T&E fishes is low (3.85 × 10−9∼8.20 × 10−4), with perfluorohexanoic acid (PFHxA) and perfluorooctanoic acid (PFOA) as the high-risk pollutants. The risk in the middle and lower reaches of the river is higher than in the upper reaches. This study provides a new approach for obtaining chronic toxicity data and conducting risk assessments for T&E species, advancing the protection of T&E species worldwide.

Which pollutants and sources should be prioritized for control in multi-pollutants complex contaminated areas?

Risk assessment and source identification of multi-pollutants are essential for accurate control of soil contamination. However, complexity in pollutant properties and diversity in source types raise challenges to the target. Therefore, this study constructed a hierarchical ecological risk quantification method combined with risk ranking, risk of single pollutant using potential affected fraction (PAF), and joint risk of multi-pollutants employing msPAF. Taking regional contamination in South China as a case, the risk ranking was determined, while single and joint effects showed msPAF reaching 79.4 %, with risk as heavy metals (HMs) > per- and polyfluoroalkyl substances (PFASs) > polycyclic aromatic hydrocarbons (PAHs). Meanwhile, an integrated source apportionment method was established from three layers by principal component analysis to classify source types, multiple linear regression of distance to identify key sources, and positive matrix factorization to track omitted sources. Consequently, key sources were captured, with 80.8 %−93.2 % contribution of farmland and electroplating to three main HMs, 52.2 %−69.4 % contribution of roads to three main PAHs, and 71.1 %−73.2 % contribution of electroplating to two main PFASs. Further, omitted sources were tracked with contribution of 31.2 %−84.1 % to eight pollutants. The established methods can identify control targets, including high-risk pollutants and their key sources.

Integration of Nontarget Screening and QSPR Models to Identify Novel Organophosphate Esters of High Priority in Aquatic Environment.

With the development of large numbers of novel organophosphate esters (OPEs) alternatives, it is imperative to screen and identify those with high priority. In this study, surface water, biofilms, and freshwater snails were collected from the flow-in rivers of Taihu Lake Basin, China. Screened by target, suspect, and nontarget analysis, 11 traditional and 14 novel OPEs were identified, of which 5 OPEs were first discovered in Taihu Lake Basin. The OPE concentrations in surface water ranged from 196 to 2568 ng/L, with the primary homologue tris(2,4-ditert-butylphenyl) phosphate (TDtBPP) being newly identified, which was likely derived from the transformation of tris(2,4-ditert-butylphenyl) phosphite. The majority of the newly identified OPEs displayed substantially higher bioaccumulation and biomagnification potentials in the biofilm-snail food chain than the traditional ones. Quantitative structure-property relationship models revealed both hydrophobicity and polarity influenced the bioaccumulation and biomagnification of the OPEs, while electrostatic attraction also had a contribution to the bioaccumulation in the biofilm. TDtBPP was determined as the utmost priority by toxicological priority index scheme, which integrated concentration, bioaccumulation, biomagnification, acute toxicity, and endocrine disrupting potential of the identified OPEs. These findings provide novel insights into the behaviors of OPEs and scientific bases for better management of high-risk pollutants in aquatic ecosystem.

Occurrence, distribution, and potential ecological risks of antibiotics in a seasonal freeze-thaw basin

Antibiotics have gained increasing attention as pharmaceuticals widely existing in human society. Under low temperature conditions, antibiotics tend to have higher environmental persistence, which poses a potential threat to ecological environment, but research on antibiotics in low-temperature basins is still lacking. Therefore, for investigating occurrence, spatio-temporal distributions, and ecological risks of antibiotics in a seasonal freeze-thaw basin, rivers in Tumen River basin were selected and sampled, including 25 samples during the river-freezing season and 27 samples during the non-freezing season. Overall, climate characteristics of different latitudes and renewal frequency of antibiotics are important factors that lead to diversity of antibiotics in basins. Eleven target antibiotics were detected and their average concentrations during the river-freezing season (0.83–27.5 ng L−1) were lower than that during the non-freezing season (2.80–45.30 ng L−1), severely impacted by river flow, ice sealed-melting, and local feeding practices. In addition, total antibiotic concentrations are usually highest in downstream areas of human settlements, receiving input from husbandry and sewage, respectively. Through ecological risk assessment, norfloxacin and amoxicillin posed high risks to algae, which were identified as high-risk pollutants in basin

Novel BTEX-degrading strains from subsurface soil: Isolation, identification and growth evaluation

Monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and o, m, and p-xylenes (BTEX) are high-risk pollutants because of their mutagenic and carcinogenic nature. These pollutants are found with elevated levels in groundwater and soil in Canada at several contaminated sites. The intrinsic microbes present in the subsurface have the potential to degrade pollutants by their metabolic pathways and convert them to non-toxic products. However, the low subsurface temperature (5–10 °C) limits their growth and degradation ability. This study examined the feasibility of subsurface heat augmentation using geothermal heating for BTEX bioremediation. Novel potent BTEX-degrading bacterial strains were isolated from soil at 3.0, 42.6, and 73.2 m depths collected from a geothermal borehole during installation and screened using an enrichment technique. The selected strains were identified with Sanger sequencing and phylogenetic tree analysis, revealing that all the strains except Bacillus subtilis are novel with respective to BTEX degradation. The isolates, Microbacterium esteraromaticum and Bacillus infantis showed the highest degradation with 67.98 and 65.2% for benzene, 72.8 and 71.02% for toluene, 77.52 and 76.44% for ethylbenzene, and 74.58 and 74.04% for xylenes respectively. Further, temperature influence at 15 ± 1 °C, 28 ± 1 °C and 40 ± 1 °C was observed, which showed increased growth by two-fold and on average 35–49% more biodegradation at higher temperatures. Results showed that temperature is a positive stimulant for bioremediation, hence geothermal heating could also be a stimulant for in-situ bioremediation.

Pollution and Risk Level Assessment of Pollutants in Surface Water Bodies

The study was carried out to assess the pollution, impact, and risk level to the surface water environment of pollutants in the water bodies of Soc Trang province, Vietnam. The parameters for evaluating surface water quality and risks included temperature, pH, TSS, DO, BOD, COD, NH4+-N, NO2--N, NO3--N, PO43--P, Cl-, Fet, and coliform. Surface water samples were collected at 35 locations with a frequency of six times (February, April, June, August, October, and December) in 2022. The water quality index (WQI), impact and risk level (risk quotient or RQ, RQ-F), correlation analysis, and principal component analysis (PCA) were utilized in the study. The results show that the surface water has been seriously polluted due to organic matter, nutrients, microorganisms, iron, and salinity. The values of WQI in the dry and rainy seasons fluctuated between bad and very good, indicating that surface water quality is suitable for water transport and other purposes with higher quality requirements. TSS, COD, Fet and coliform have a high impact and risk for the environment in this study area. There were no environmental impacts and risks to NO3--N. Locations with many high-risk pollutants were mainly distributed in residential and coastal areas. The significant negative correlation between the WQI and RQ indicated that the lower the WQI, the higher the environmental risk. The PCA results show that at least six polluting sources affected water quality and caused environmental risks. The results of this study contribute essential and valuable information for improving water quality in the study area through the assessment of environmental impacts and risks. Doi: 10.28991/CEJ-2023-09-08-03 Full Text: PDF

Comprehensive profiling of the distribution, risks and priority of pharmaceuticals and personal care products: A large-scale study from rivers to coastal seas

Pharmaceuticals and personal care products (PPCPs) have captured global concern due to their detrimental effects on aquatic organisms. Thirty PPCPs were analyzed in the water of the Jiaozhou Bay watershed, the Yellow Sea (YS) and the East China Sea (ECS) in China to investigate the distribution and risk of PPCPs from rivers to coastal seas, which are not yet well documented. The results showed the prevalence of the target PPCPs with a downward trend in detection frequencies and total concentrations from rivers (675 ng/L on average) to bay (166 ng/L) and to coastal seas (103 ng/L). Antibiotics and personal care products (PCPs) were dominated by amoxicillin (AMOX) and p-hydroxybenzoic acid, respectively, while the dominant estrogens were inconsistent in different regions. Spatially, the total PPCP concentrations were higher in the ECS than that in the YS due to the larger quantity of sewage flowing into the ECS. Additionally, higher total PPCP concentrations were appeared in the southeastern waters outside the Yangtze estuary and Hangzhou Bay of the ECS. The PPCP mixtures might pose medium to high risk to aquatic organisms in general. The total risk quotient (RQT) of antibiotics and PCPs to algae was higher than that to crustacean and fish, while estrogens may cause the greatest damage to fish. Despite the higher PPCP concentrations in river water than in seawater, the RQT of PPCPs in bay water was generally higher than that in river water, which may be associated with the susceptibility of marine organisms. Furthermore, the high-risk pollutants that need special concern in different regions were clarified, showing that AMOX, 17ß-estradiol, and estriol deserve the highest-priority in rivers, bay, and coastal waters, respectively.

Synthesis of porous materials by the modification of coal fly ash and its environmentally friendly use for the removal of heavy metals from wastewater

Wastewater is a complex mixture of many pollutants, where the high-risk pollutants are heavy metals (HMs) in industrial wastewater due to their difficult removal. In this study, the waste CFA was used as the main raw material for production of new innovated flocculants porous particles by modification of coal fly ash (CFA) using a multi-step base–acid–base (NaOH–HCl–NaOH) modification method. The morphological structure and elemental composition of the prepared MCFA were analyzed through characterization analysis, i.e., SEM, EDX, FT-IR, BET, XPS, and XRD. Results found that the surface area of the flocculant particles of MCFA was increased from 5.241 to 32.011 m2/g, which increased the adsorption process of HMs (Mn2+, Cu2+, Ni2+, and Pb2+). The maximum removal efficiencies (Re %) of MCFA for Mn2+, Cu2+, Ni2+, and Pb2+ were recorded at 94.26%, 95.88%, 71.04%, and 99.91%, respectively. The Freundlich isotherm model was fitted for the adsorption process, and the maximum adsorption amounts of MCFA for Mn2+, Cu2+, Ni2+, and Pb2+ were 558.9219, 0.4341, 210.9737, and 12.1957 mg/g, respectively. Moreover, the kinetic model indicated that physicochemical adsorption occurred between the adsorbate materials and the adsorbent.

Global attributed burden of death for air pollution: Demographic decomposition and birth cohort effect

BackgroundTo identify the high-risk pollutants and evolving patterns of attributed mortality burden, more detailed evidence is needed to examine the contribution of different air pollutants to death across the disease spectrum, particularly considering population change as well as the context of the era. MethodsWe explored the evolving patterns of all-cause and disease-specific deaths attributed to overall air pollution and its main subcategories by using the estimated annual percentage change and additionally assessing the contribution of population growth and ageing to death burden using the decomposition method. Age-period-cohort model and Joinpoint analysis were used to evaluate birth cohort effects specific-disease death burden owing to high-risk air pollution subcategories. FindingsThe number of deaths caused by air pollution increased by 2.62 %, which was driven by ambient particulate matter pollution and ambient ozone pollution, whereas household air pollution decreased. Population ageing contributed 28.88 % of the deaths increase change for air pollution. Compared with other subcategories, the age-standardized mortality rate (ASMR) attributed to ambient particulate matter pollution remained the heaviest attributed death burden, comprehensively considering of bivariate burden. In 2019, ischemic heart disease attributed to ambient particulate matter pollution exhibited the highest ASMR, which may be impacted by a rapid increase era from 1950 to 1980 birth cohort in woman and 1970 to 1990 birth cohort in man. Diabetes mellitus attributed to ambient particulate matter pollution showed the largest increase for ASMR, which was driven primarily by men born 1910–1975 and women born 1950–1975.Uzbekistan showed the highest ASMR for ischemic heart disease, with Equatorial Guinea showing the fastest increase for diabetes mellitus. ConclusionPriority intervention targets for air pollution and health should emphasize the susceptibility of the elderly population as well as the structural factors of the era, in particular sensitive diseases to the ambient particulate matter pollution.

Methylene blue removal using raw and modified biomass Plumeria alba (white frangipani) in batch mode: isotherm, kinetics, and thermodynamic studies.

Hazardous dyes used in textile industries are considered high-risk pollutants to the environment. The raw as well as acid-treated Plumeria alba (white frangipani) leaf powder (WFLP and SWFLP) were used for the adsorption of methylene blue (MB) that is available in industrial wastewaters following the batch adsorption technique. The characterizations of adsorbents were done by FTIR, SEM, EDX, TGA, and zeta potential parameters. The adsorption was considered for the effects of temperature, initial dye concentration, solution pH, adsorbent dosage, and contact time. The experimental results obtained in the adsorption of MB were examined by nonlinear error functions like chi-square (χ2), ARE, and MPSD for three isotherm models: Langmuir, Freundlich, and Temkin. The maximum monolayer adsorption capacity, qmax (mg/g), was 45.45mg/g for raw WFLP and 250mg/g for SWFLP. The adsorbents fitted to the pseudo-second-order kinetic model (R2 = 0.99) using the experimental data of batch adsorption. The thermodynamic studies explained the spontaneity and nature of adsorption for raw and acid-treated adsorbents. The batch experimental results and characterizations of the adsorbents revealed that the selected adsorbents would be the best adsorbents for the removal of MB from the wastewater solution.

Occurrence, exposure and risk assessment of semi-volatile organic compounds in Chinese homes

Indoor semi-volatile organic compounds (SVOCs) can have a significant impact on human health. Previous studies involved the detection of limited classes of indoor SVOCs in different regions of China. However, overall indoor pollution profiles and the associated health risks via multiple exposure pathways remain unclear. High-throughput screening of SVOCs would help clarify the overall indoor pollution status and identify high-risk pollutants. We collected indoor air and dust samples from 35 Chinese homes and investigated the occurrence of a wide range of SVOCs. Ninety-seven SVOCs including phthalate esters (PAEs), polycyclic aromatic hydrocarbons (PAHs), organophosphate esters, alcohols, fatty acids, phenols, etc., were detected in the air (total concentrations: 0.13–48 μg/m3; median: 3.4 μg/m3) and dust (total concentrations: 120–1500 μg/g; median: 490 μg/g) samples. PAEs were the most abundant, accounting for 55.3 ± 28.6% and 43.4 ± 16.9% of the total SVOC concentrations in the air and dust samples respectively. Human exposure and health risks of 34 SVOCs with detection frequencies >10% were assessed based on inhalation, ingestion and dermal absorption of SVOCs from air and dust by infants and adults. In the case of indoor SVOCs with log Koa < 9, inhalation and dermal contact with air was >90% for adults and >69% for infants. The following five SVOCs in air samples posed significant non-carcinogenic risks and are listed based on their decreasing risk level: dibutyl phthalate > phenanthrene > stearic acid > methyl palmitate > lauryl alcohol. Four PAHs with 2–4 rings posed potential carcinogenic risks, with phenanthrene exceeding the acceptable risk level of 10−4. The high risks posed by SVOCs were due to inhalation exposure. Therefore, keeping the air concentrations of SVOCs, especially that of PAEs and PAHs under check would greatly benefit human health in indoor environments.

Intracellular and extracellular protective mechanisms of the anammox consortia against exogenous sulfadimidine

Antibiotics and antibiotic resistance genes (ARGs) have been recognized as emerging high-risk pollutants for human and animal health. This study systematically investigated the comprehensive effects of a typical antibiotic (sulfadimidine, SDM) in livestock and poultry breeding wastewater on the anammox process, with the aim of elucidating the intracellular and extracellular protective mechanisms of the anammox consortia to the antibiotic stress. Results revealed that the high-concentration SDM significantly reduced the specific anammox activity (SAA) by 37.8%. Changes in the abundance of Candidatus Kuenenia showed a similar trend with that of SAA, while other nitrogen-related microorganisms (e.g., Nitrosomonas and Nitrospira) contributed to the nitrogen removal especially during the inhibitory period. Resistance of the anammox consortia to SDM mainly depended on the protection of ARGs and EPS. Network analysis revealed the host range of eARGs was relatively larger than that of iARGs, and intI1 was closely associated with representative denitrifiers. In addition, metaproteomic analysis and molecular docking results indicated that abundant proteins in EPS could detain SDM in the extracellular matrix through forming complex via hydrogen bond. These findings provide a guidance for the stable operation of anammox process and ARGs transfer controlling.

Genetic system underlying responses of Cryptococcus neoformans to cadmium.

Cryptococcus neoformans, basidiomycetous pathogenic yeast, is basically an environmental fungus and, therefore, challenged by ever changing environments. In this study, we focused on how C. neoformans responds to stress caused by cadmium that is one of high-risk pollutants. By tracking phenotypes of the resistance or sensitivity to cadmium, we undertook forward and reverse genetic studies to identify genes involved in cadmium metabolism in C. neoformans. We found that the main route of Cd2+ influx is through Mn2+ ion transporter, Smf1, which is an ortholog of Nramp (natural resistance-associated macrophage protein 1) of mouse. We found that serotype A strains are generally more resistant to cadmium than serotype D strains and that cadmium resistance of H99, a representative of serotype A strains, was found to be due to a partial defect in SMF1. We found that calcium channel has a subsidiary role for cadmium uptake. We also showed that Pca1 (P-type-ATPase) functions as an extrusion pump for cadmium. We examined the effects of some metals on cadmium toxicity and suggested (i) that Ca2+ and Zn2+ could exert their protective function against Cd2+ via restoring cadmium-inhibited cellular processes and (ii) that Mg2+ and Mn2+ could have antagonistic roles in an unknown Smf1-independent Cd2+ uptake system. We proposed a model for Cd2+-response of C. neoformans, which will serve as a platform for understanding how this organism copes with the toxic metal.

Profiling of the spatiotemporal distribution, risks, and prioritization of antibiotics in the waters of Laizhou Bay, northern China

We investigated the spatiotemporal distributions, risks, and prioritization of 15 widely used antibiotics in Laizhou Bay (LZB). Water samples (145) were collected from LZB and its estuaries and analyzed. Twelve antibiotics, with total concentrations of 241–1450 and 69–289 ng L−1 in estuarine water and seawater, respectively, were detected, with the contributions of norfloxacin, ciprofloxacin, and amoxicillin exceeding 70%. Amoxicillin was firstly determined, which contributed to 20% and 46% of the total antibiotics during summer and spring, respectively. Higher antibiotic concentrations were observed in the sea located adjacent to aquaculture bases and the Yellow River Estuary, which are significantly influenced by mariculture and riverine inputs, respectively. Veterinary antibiotics showed higher total concentrations in summer compared to spring, indicating a higher degree of their usage in mariculture in summer. The antibiotic mixtures posed high risk to algae and low to medium risks to crustaceans and fish. Amoxicillin and norfloxacin were identified as high-risk pollutants. Additionally, amoxicillin and ciprofloxacin showed medium to high resistance development risks. Previous studies on antibiotics in the LZB did not determined amoxicillin and thus underestimated antibiotic contamination, ecological risk, and resistance development risk. Amoxicillin, norfloxacin, and ciprofloxacin should be prioritized in risk management.

Treatment Effect and Ecological Risk Assessment of Typical Antibiotics in Wastewater from Large-scale Dairy Farms in Tianjin

To obtain the content level and treatment efficiency of typical antibiotics in wastewater treatment in large-scale dairy farms in Tianjin, the SPE-UPLC-MS/MS (ultra-high performance liquid chromatography tandem triple quadruple mass spectrometry combined with solid-phase extraction for pretreatment) technology was utilized to investigate and monitor seven typical antibiotics in wastewater from 12 large-scale dairy farms in Tianjin. Antibiotic residues were detected in 12 large-scale dairy farms before and after wastewater treatment. In the wastewater before treatment, the detection rates of tilmicosin (TIL), oxytetracycline hydrochloride (OTC), sparfloxacin (SPA), sulfathiazloe (STZ), ofloxacin (OFL), and sarafloxacin hydrochloride (SAR) were all 100%, whereas the detection rate of sulfadiazine (SDZ) was 83.33%. Among them, TIL and OTC were the main antibiotic components in untreated wastewater, the concentrations were 25.21 μg·L-1 and 9.87 μg·L-1, respectively. The detection rates of SDZ and OFL in the treated wastewater dropped to 25.00% and 41.66%, respectively. The main components were TIL and OTC and the concentrations were 11.30 μg·L-1 and 3.71 μg·L-1, respectively. There were significant decreases in the concentrations. The treatment effect on antibiotics from different farms ranged from 24.95% to 81.05%. The comprehensive treatment effect of the anaerobic-anoxic-oxic (AAO) treatment process was better than that of the anoxic-oxic (AO) treatment process. OFL, SAR, and OTC were the main high-risk pollutants in treated wastewater. Each large-scale dairy farm contained one or more antibiotic with RQs>1, and their emissions pose an ecological risk to the environment.

Biomimetic Planar Polymer Membranes Decorated with Enzymes as Functional Surfaces.

Functional surfaces were generated by a combination of enzymes with polymer membranes composed of an amphiphilic, asymmetric block copolymer poly(ethyleneglycol)- block-poly(γ-methyl-ε-caprolactone)- block-poly[(2-dimethylamino)ethylmethacrylate]. First, polymer films formed at the air-water interface were transferred in different sequences onto silica solid support using the Langmuir-Blodgett technique, generating homogeneous monolayers and bilayers. A detailed characterization of these films provided insight into their properties (film thickness, wettability, topography, and roughness). On the basis of these findings, the most promising membranes were selected for enzyme attachment. Functional surfaces were then generated by the adsorption of two model enzymes that can convert phenol and its derivatives (laccase and tyrosinase), well known as high-risk pollutants of drinking and natural water. Both enzymes preserved their activity upon immobilization with respect to their substrates. Depending on the properties of the polymer films, different degrees of enzymatic activity were observed: bilayers provided the best conditions in terms of both overall stability and enzymatic activity. The interaction between amphiphilic triblock copolymer films and enzymes is exploited to engineer "active surfaces" with specific functionalities and high efficacy resulting from the intrinsic activity of the biomolecules that is preserved by an appropriate synthetic environment.