Conventional Pollutants Research Articles

Short time PM2.5 prediction model for Beijing-Tianjin-Hebei region based on Generalized Space Time Autoregressive (GSTAR)

In recent years, with the rapid development of China’s economy and urbanization, the irrational industrial structure, large energy consumption, and increased car ownership have made China’s air pollution increasingly serious, especially in Beijing-Tianjin-Hebei, Yangtze River Delta, and the Pearl River Delta. As the primary pollutant affecting the air quality in the Beijing-Tianjin-Hebei region, the accurate prediction of PM2.5 concentration is of great significance for predicting heavy pollution weather, formulating the start-up mechanism of emergency plan and optimizing the production of enterprises. This study used the online hourly data of conventional pollutants from 80 national control stations in Beijing, Tianjin and Hebei from May 1, 2015 to May 31, 2019. Considering the influence of time and space, the GSTAR model of PM2.5 prediction is established. Comparing the prediction results of GSTAR model with ARMA and STAR, the validity of GSTAR model is verified by applying relevant accuracy evaluation indicators.

Role of treatment configuration in simultaneous removal of priority phthalic acid esters and nitrogen in a post anoxic integrated biofilm activated sludge system

To develop future wastewater treatment systems, focus is to improve/investigate existing biological wastewater treatment processes for the concurrent treatment of conventional pollution parameters (essentially nitrogen) and micro pollutants. Majority of the existing biological wastewater treatment systems were not designed for the removal of micro pollutants. This study focuses on understanding the role of treatment configuration for efficient removal of nitrogen and priority phthalic acid esters (PAEs) from real municipal wastewater in an integrated biofilm activated sludge (IBAS) system. The reactor was operated in two phases: Run I, without external carbon source in anoxic reactor and Run II, a nitrogen removal process, with partial diversion of untreated wastewater in anoxic reactor. Nitrogen removal was 70 ± 12% in both operational phases, however, during Run I, removal of PAEs fluctuated with an average removal of 60–78%. Comparatively, removal of PAEs in Run II varied over a smaller range with average removal increased to 89–95%. In both operational scenarios, secondary oxic tank contributed maximum to the overall removal of PAEs in treatment system. Mass balance calculations showed significant contribution of biodegradation towards overall removal of PAEs which was enhanced by the supply of external carbon source. Kinetics and model output supported the PAEs removal performance observed in different reaction environments of IBAS process. A correlation between food to microorganism (F/M) ratio and PAEs removal showed increase in PAEs removal with decrease in F/M ratio. The study showed that treatment configuration and F/M ratio may be one of the guiding parameters for efficient removal of PAEs in biological wastewater treatment.

Triclosan enhances short-chain fatty acid production from sludge fermentation by elevating transcriptional activity of acidogenesis bacteria

Triclosan (TCS) is an emerging contaminant in waste activated sludge (WAS). However, the effects of TCS on WAS anaerobic fermentation is still unknown. Herein, we investigated the impacts of different TCS levels on the short-chain fatty acid (SCFA) accumulation. TCS at 100 mg/kg TSS (total suspended solids) significantly (p < 0.05) enhanced SCFA production by 35.8 ± 4.1% through increasing the production of propionic and butyric acid, while the higher TCS level inhibited the SCFA production processes. The results of batch tests with real sludge showed that 100 mg/kg TSS TCS enhanced acidogenesis process and had no significant impact on other processes, while higher TCS level caused negative effects on acidogenesis, acetogenesis and methanogenesis. Generally, 2,4-dichlorophenol was considered as the main metabolic product of TCS under anaerobic condition. However, in this study, TCS was found to be converted into (Z)-4-(2,4-dichlorophenoxy)penta-1,3-dien-3-ol, 2,4-dichloro-1-(4-chloro-2-methoxyphenoxy)benzene and other substances, and its hypothetical metabolic pathway were reformulated. The microbial community structure in the WAS anaerobic fermentation system did not significantly change with TCS addition, but 100 mg/kg TSS TCS contributed to the modest enrichment of SCFA producers. Further analyses of key enzyme activity and abundance of enzyme-encoded genes revealed that TCS at 100 mg/kg TSS up-regulated the expression of enzyme-coding genes (i.e. butyrate kinase (BK) and oxaloacetic acid carboxylase (OAATC)), and this is the primary reason for the increased SCFA production. This work provides a new insight for pollutant effects in WAS anaerobic fermentation, which will help to reveal the impact of emerging contaminants and relearn the role of conventional pollutants.

Effectiveness of single-stage and sequential sludge digestion on removal of recalcitrant pharmaceuticals and conventional pollutants

The fate of pharmaceuticals, azithromycin (AZI), carbamazepine (CBZ), diclofenac (DCF), mefenamic acid (MFA), ibuprofen (IBP) and one ibuprofen metabolite (1-hydroxy ibuprofen (1-OH IBP)), were investigated in single-stage anaerobic (AN) and sequential anaerobic/aerobic/anoxic (AN/AERO/ANOX) sludge digestion under thermophilic conditions (55 °C). Intermittent aeration was used for the sequential AERO/ANOX vessel. Digesters showed an increase in CBZ, MFA and DCF at a hydraulic retention time (HRT) of 18 days as organic matter is degraded. However, the rate of increase for MFA was 10 times lower in sequential digestion compared to single-stage AN digestion (control). Sequential AN/AERO/ANOX digestion showed a 50% decrease in IBP levels while increasing IBPs aerobic metabolite 1-OH IBP by 12%. The control AN digester showed a 62% increase in IBP and a 34% decrease in 1-OH IBP. Sequential digestion provided other benefits, including reduced ammonia generation (44.5%), improved solids removal (4.1%) and enhanced digestate dewaterability (20%) compared to the control.

Evaluating Pollutants of Emerging Concern in Aquatic Media Through E-PRTR Regulation. A Case Study: Cordoba, Spain, 2009-2018

The E-PRTR EU Regulation can be followed for the evaluation of the level of pollutants of emerging concern in treated wastewater. This regulation is of regional responsibility in the UE, and establishes for the Andalusian region of Spain the following pollution parameters as mandatory to be controlled periodically in treated wastewater in Waste Water Treatment Plants (WWTPs) with more than 100.000 equivalent inhabitants of treatment capacity: COD, N-Kjeldahl, total P, Cl-, F- (conventional pollution); As, Cd, Cr, Cu, Hg, Ni, Zn and Pb, as heavy metals; PAHs (polycyclic aromatic hydrocarbons), adsorbed organic halides (AOXs), benzene and chloroform, as organic compounds. This paper shows results obtained in the application of the E-PRTR Regulation to the wastewater of Cordoba during 2009-2018. As shown, average of COD, N-Kjeldahl an total P values, respectively, in urban and treated wastewater were 604 and 89 mg/L, 54.1 and 33.4 mg/L and 3.4 and 1.4 mg/L. With respect to heavy metals, the mean content in treated wastewater was 0.135 mg/L, starting from 0.226 mg/L in raw wastewater. The majority of these are Cu and Zn (0.043 mg/L and 0.107 mg/L, respectively, in raw wastewater). For pollutants of emerging concern, the mean content of PAHs was 13 ng/L in treated water vs 31 ng/L in raw wastewater. Moreover, concentration of AOXs in raw wastewater was of 20 ng/L while in treated wastewater decreased up to 16 ng/L. Also, benzene content in raw wastewater and treated wastewater decreased from 40 ng/L to 11 ng/L. Finally, the major organic compound was chloroform, with a level in raw wastewater of 5.6 ng/L that was reduced along the treatment up to 3.2 ng/L. The provided data indicated a low concentration of the compounds of emerging concern in the wastewater of Cordoba and its minimal impact on the receiving aquatic environment (the Guadalquivir river).

Defending blue sky in China: Effectiveness of the “Air Pollution Prevention and Control Action Plan” on air quality improvements from 2013 to 2017

Air pollution control has become one of the top priorities of China's “Ecological Civilization” development. As a quick response to the 2013 PM2.5 episodes, the Chinese Government issued the “Air Pollution Prevention and Control Action Plan” as the national strategy and roadmap for air quality improvements consisting of phased quantitative targets and concrete measures. Taking this into account, this study explores the spatiotemporal variations of the five conventional pollutants—PM2.5, PM10, SO2, NO2, and O3—as well as the Air Quality Index and primary pollutants in 338 Chinese cities from 2013 to 2017 in order to comprehensively understand China's current air pollution situation and evaluate the effectiveness of the Action Plan. The results indicate that: (1) the overall air quality has been significantly improved, with the concentrations of PM2.5, PM10, and SO2 decreasing noticeably, although the still high PM level, the dramatically increasing O3 concentration, and the stagnant amounts of NO2 present further challenges, along with the intensification of regional compound air pollution problems; (2) in contrast to the three key regions under the Action Plan exhibiting significant decreases in PM and SO2, the Fen-Wei Plain (FWP) is suffering from serious compound pollution, suggesting that there is an urgent need for the development of a regional joint prevention and control mechanism in the FWP and similar areas; (3) with the exception of the common pollution hot spots mainly concentrated in the FWP as well as Beijing-Tianjin-Hebei (BTH) and its surrounding regions, the distribution of each pollutant exhibited remarkable spatial heterogeneity due to their distinctive emission sources, a finding that strongly indicates the need for regionally differentiated management; and (4) the most frequent primary pollutant at the national level was O3, followed by PM2.5 and PM10. In the Wuhan Metropolitan Area (WHM), Changsha-Zhuzhou-Xiangtan Metropolitan Area (CZT), and Sichuan-Chongqing Region (CY), PM2.5 pollution is playing the dominant role, while in the FWP, BTH, Yangtze River Delta region (YRD), and Pearl River Delta region (PRD), the synergistic control of PM2.5 and O3 pollutants is urgently needed as soon as possible, which will require that more attention be paid to emission mitigation in the transportation sector, as well as the synergistic control of NOx and VOC emissions.

Grand Challenges Cannot Be Treated in Isolation

If not well understood, linkages among the grand challenges of poverty alleviation, environment protection, and climate mitigation could lead to paralyzed policies and even conflicting consequences. Quick changes need to happen at the institutional, societal, and scientific levels to maximize the synergy of addressing these challenges instead of treating them in isolation.

“Qualitative Analysis to Assess the Best Renewable Energy Scenario for Sustainable Energy Planning”

Rural population in developing nation is having limited access to the clean and modern energy sources. Rural poor in India are mostly dependent on electricity, fire wood, dung, and biomass for their domestic energy need. Due to the dependence on conventional energy sources pollution and rural health are the issue of concern which directly affect on the national productivity. Ministry of New and Renewable Energy of the Government of India giving stress to intensify the energy supply and modern sources of energy to rural area up to normal consumption level through renewable energy sources The aim of the present study is to determine the best renewable energy scenario for sustainable development of rural area. For this aim, author used both quantitative and qualitative analysis technique to determine the best energy scenario for application. For quantitative analysis multi objective goal programming model is used and the result obtained by it validated with multi-attribute decision making approach. The present work specifically focused on Analytic Hierarchy Process (AHP) methodology. In the proposed method, the weights of the selection criteria are determined by pair-wise comparison matrices of the AHP. Results indicate that Cost Employment Generation Scenario (CEGS) is the most appropriate renewable energy option.

Incorporating health co-benefits into regional carbon emission reduction policy making: A case study of China’s power sector

How to maximize the synergies between CO2 and conventional air pollutants (CAP) emission reductions have been extensively discussed in previous studies. However, few studies have explored the essential policy concern, which is, how to maximize the social benefits including both carbon mitigation and human health co-benefits from the co-abated conventional air pollutants. Besides, for some sectors that have extensive inter-regional trade, using more low-carbon technologies to produce goods (and thus reducing its own CO2 emissions) in one region may influence the need of goods imported from another region and consequently the associated conventional air pollutants emissions. Therefore, the health co-benefits may also be transferred to the other regions. This transfer effect has seldom been quantified before. To bridge these research gaps, this paper took China’s power sector as an example and quantified the operating margin (OM) emission factors of SO2, NOX and PM2.5 in China’s six power grids. Then the co-abatement rates of these three pollutants when reducing each kiloton of CO2 in different grids were calculated. Finally, considering different grids’ meteorological conditions, population densities, baseline incidences, baseline death rates, and the inter-grid electricity trade, this paper computed and compared the values and regional distribution of health co-benefits per kiloton of CO2 reduced. It is found that grids with the highest co-abatement rates in conventional air pollutants do not necessarily bring maximum health co-benefits. Although the northeast grid could achieve the largest co-reduction in NOX and PM2.5, it is the south grid that has the largest health co-benefits. The differences in health co-benefits of the same amount of CO2 reduced among grids vary as much as fivefold. Besides, the share of trans-grid health co-benefits can be as high as 14.1% if CO2 reduction takes place in the east grid. Therefore, it is suggested that the health co-benefits of CO2 reduction and their trans-regional distribution should be taken seriously when making regional carbon emission reduction plans, in order to maximize the social benefits of CO2 reduction.

Are pharmaceuticals removal and membrane fouling in electromembrane bioreactor affected by current density?

Pharmaceutical active compounds (PhACs) have been detected at significant concentrations in various natural and artificial aquatic environments. In this study, electro membrane bioreactor (eMBR) technology was used to treat simulated municipal wastewater containing widely-used pharmaceuticals namely amoxicillin (AMX), diclofenac (DCF) and carbamazepine (CBZ). The effects of varying current density on the removal of PhACs (AMX, DCF and CBZ) and conventional pollutants (chemical oxygen demand (COD), dissolved organic carbon (DOC), humic substances, ammonia nitrogen (NH4-N), nitrate nitrogen (NO3-N) and orthophosphate (PO4-P) species) were examined. High COD and DOC removal efficiencies (~100%) were obtained in all the experimental runs regardless of applied current density. In contrast, enhanced removal efficiencies for AMX, DCF and CBZ were achieved at high current densities. Membrane fouling rate in eMBR with respect to conventional MBR was reduced by 24, 44 and 45% at current densities of 0.3, 0.5 and 1.15 mA/cm2, respectively. The mechanism for pharmaceutical removal in this study proceeded by: (1) charge neutralization between negatively-charged pharmaceutical compounds and positive electro-generated aluminium coagulants to form larger particles and (2) size exclusion by membrane filtration.

Interaction of graphene oxide with co-existing arsenite and arsenate: Adsorption, transformation and combined toxicity

The outstanding commercial application potential of graphene oxide (GO) will inevitably lead to its increasing release into the environment, and then affect the environmental behavior and toxicity of conventional pollutants. Interactions between arsenite [As (III)]/arsenate [As (V)] with GO and their combined toxicity to Chlorella pyrenoidosa were investigated. Under abiotic conditions, approximately 42% of the adsorbed As (III) was oxidized by GO with simulated sunlight illumination, which was induced by electron-hole pairs on the surface of GO. Co-exposure with GO greatly enhanced the toxicity of As (III, V) to alga. When adding 10 mg/L GO, the 72 h median effect concentration of As (III) and As (V) to C. pyrendoidosa decreased to 12.7 and 9.4 mg/L from 30.1 and 16.3 mg/L in the As alone treatment, respectively. One possible mechanism by which GO enhanced As toxicity could be that GO decreased the phosphate concentration in the algal medium, and then increased the accumulation of As (V) in algae. In addition, transmission electron microscope (TEM) images demonstrated that GO acted as a carrier for As (III) and As (V) transport into the algal cells. Also, GO induced severe oxidative stress, which could have subsequently compromised important detoxification pathways (e.g., As complexation with glutathione, As methylation, and intracellular As efflux) in the algal cells. Our findings highlight the significant impact of GO on the fate and toxicity of As in the aquatic environment.

Effect of gold and iron nanoparticles on photocatalytic behaviour of titanium dioxide towards 1-butyl-3-methylimidazolium chloride ionic liquid

The high water solubility, chemical stability and low volatility of ionic liquids (ILs) have made them potentially persistent than conventional pollutants and toxic to the aquatic organisms. Therefore, extensive research efforts are being directed with an aim to develop cheap and efficient protocols to reduce the uncontrolled release of ILs in the environment. In the same line of action, titanium dioxide (TiO2) loaded with gold and iron nanoparticles were trialled for the photocatalytic degradation of highly concentrated 1-butyl-3-methylimidazolium chloride [BmimCl] ionic liquid. Furthermore, results pertaining to the degradation of the [BmimCl] using TiO2 loaded with gold nanoparticles (AuNPs) were compared with results obtained by using TiO2 loaded with Fe (NO3)3.9H2O and pristine TiO2 under same set of conditions. It was found that TiO2 decorated AuNPs demonstrated 7 times higher photocatalytic degradation for highly concentrated [BmimCl] in 60 min of reaction time in comparison to the pristine TiO2. Congruently, investigations also revealed that TiO2 loaded AuNPs expressed 3.3 times higher photocatalytic degradation of [BmimCl] in comparison to conventional photocatalyst TiO2@Fe under same reaction conditions. The higher photocatalytic performance associated with TiO2 loaded AuNPs was due to the enhanced Schottky barrier, which could have minimized the photocharge carrier resistance separation and migration. The mechanism for photocatalytic degradation of [BmimCl] using TiO2 loaded AuNPs has been also been described.

Evolution of four-decade atmospheric mercury release from a coal-fired power plant in North China

Coal-fired power plants (CFPPs) are an important anthropogenic emission source of atmospheric mercury (Hg). Understanding the co-benefits of conventional air pollution control devices (APCDs) on Hg reduction is crucial for reducing Hg emission from this source. In this study, atmospheric Hg emission from a pulverized coal (PC) utility boiler in North China was investigated along the emission control stage of selective catalytic reduction (SCR), electrostatic precipitator (ESP) and fabric filter (FF) and lime stone-gypsum wet flue gas desulfurization (WFGD). Historical atmospheric Hg emission from this CFPP with total 1550 MW capacity since its operation in 1976 was estimated based on the implementation of different configurations of APCDs. The results showed that a combination of SCR + ESP-FF + WFGD leads to a co-beneficial Hg control of 96%, with the in-stack Hg concentration (0.87 μg m−3) much lower than the Chinese national standard for CFPPs (30 μg m−3), and the stack Hg speciation (Hg0:Hg2+:Hgp) was in 86%:13%:1%. Mass balance analysis indicates that Hg from the input of feed coal and limestone was mainly ended up in fly ash (89%), followed by gypsum (5%), stack gas (5%) and bottom ash (1%), respectively. During the past 42 years of operation (1976–2017), the total air Hg emission from this CFPP summed to 17.62 tonnes, in which Hg0 make up 14.02 tonnes (79.5%), Hg2+ make up 3.15 tonnes (17.9%) and Hgp 0.45 tonne (2.6%). Although the speciation of emitted Hg into the atmosphere changed with respect to the configuration of APCDs, Hg0 was the most dominated emission species (64–98%) for all time. Nearly 90% of total Hg emissions occurred in the first three decades when venturi scrubber (VS) and ESP were the primary APCDs. The installation of WFGD and SCR substantially decreased the Hg emission factors by 17 times compared to the peak values during 1998–2004. This study demonstrates the combination of SCR + ESP-FF + WFGD as a best available technology (BAT) for Hg control in CFPPs in China.

Diethylhexyl phthalate removal in full scale activated sludge plants: Effect of operational parameters

Removal of emerging contaminants (ECs) is a serious concern in wastewater industry especially for public acceptance of reclaimed water. Diethylhexyl phthalate (DEHP) is one of the ubiquitous and detectable plasticizers in municipal wastewater across the globe. Water Framework Directive (2000/60/EC) has prioritized it for the establishment of discharge regulations. A cost-effective strategy, especially for developing nations, may be the re-engineering of the existing biological process for the simultaneous removal of ECs and conventional pollutants. Wastewater treatment plants are one of the main sources for DEHP occurrence in surface water. In this study, possible role of activated sludge process operational parameters in effective removal of DEHP was assessed. Principal component analysis of occurrence data showed dissimilarity with the organic and nutrient characteristics of sewage. DEHP concentration in more than half (55%) of treated wastewater samples was more than environmental quality standard value for inland and surface water bodies (1.3 μg/L). At a mixed liquor suspended solid (MLSS) concentration range of 3461–4972 mg/L, overall removal was 23.9 μg/gMLSS.d (92 ± 6%) with biodegraded portion as 22.4 μg/gMLSS.d (85 ± 4%) and sorbed portion of 1.5 μg/gMLSS.d (7 ± 4%). DEHP removal showed an increasing trend at higher oxygen uptake rates (OUR) of sludge with DEHP removal of 8.1 μg DEHP/gMLSS.d (70 ± 6%), in the OUR range of 20-28mgO2/L/h. Increase in overall removal of DEHP showed a positive correlation (r2 = 0.7) with increasing sludge retention time (SRT) and so does the decreasing food to microorganism (F/M) ratio with increasing removal of DEHP (r2 = 0.8). A temperature decrease of 13 °C caused a decrease of 30% in overall removal of DEHP.

Optimising wastewater treatment solutions for the removal of contaminants of emerging concern (CECs): a case study for application in India

Abstract The aim of this study was to produce optimal wastewater treatment solutions to calculate the removal of different contaminants of emerging concern (CECs) found in developing countries. A new methodology was developed for a decision support tool (WaStewater Decision support OptiMiser, WiSDOM), which focuses on producing treatment solutions suited to treating water for reuse to Indian Water Quality Standards. WiSDOM-CEC analyses the removal of CECs through different treatment solutions and was also used to evaluate the performance of each treatment train solution in terms of the removal of conventional pollutants using multi-objective optimisation and multi-criteria decision analysis. Information was collected on different CECs across different regions of India, and the removal of 18 different CECs through 42 wastewater treatment unit processes for five different regions of India was analysed. Comparisons between similar categories of CECs, such as non-steroidal anti-inflammatory, showed that emerging contaminants all react differently with individual treatment options. For example, the removal of ibuprofen (IBP) and naproxen (NPX) varied from &amp;gt;80% and 0%, respectively, for a solution in Karnataka involving sedimentation, submerged aerated filter, ultrafiltration and nanofiltration. In Tamil Nadu, results ranged from 36.8% to 72% for diclofenac, 10.7% to 66.5% for IBP, and 0% for NPX.

Effect of plant physiological characteristics on the removal of conventional and emerging pollutants from aquaculture wastewater by constructed wetlands

Four horizontal subsurface flow pilot-scale constructed wetlands (CWs) named as S1, S2, M1 and M2 were constructed to treat aquaculture wastewater. And two different plant species (Iris pseudacorus and Phragmites australis) were cultivated in single and mixed planting patterns in these four CWs. The removal rate of conventional pollutants (nutrient and organic compounds), antibiotics including enrofloxacin (ENR), sulfamethoxazole (SMZ), and antibiotic resistance genes (ARGs) were evaluated among those CWs. The total nitrogen and NH4+–N removal rates of all CWs were 73.24%–91.46% and 61.20%–92.27%, respectively. CWs with mixed planting patterns, such as M1 (planted with Iris pseudacorus at the forepart and Phragmites australis at the back) and M2 (alternate cultivation with Iris pseudacorus and Phragmites australis) showed better performances than CWs planted with single plant species, such as S1 (Iris pseudacorus) and S2 (Phragmites australis). However, S1 and S2 exhibited higher removal efficiencies for emerging contaminants: S1 had removal efficiencies of 77.64%, 68.70%, and 58.21% for ENR, SMZ, and total ARGs, respectively, and S2 had removal efficiencies of 81.11%, 64.94%, and 56.26% for ENR, SMZ, and total ARGs, respectively. Compared with single planting, the dominant genera in mixed planting exhibited lower relative abundance in anaerobes and higher percent of bacteria associated with nitrogen metabolism, indicating that different plant physiological characteristics affected the microbial community structures of the CWs.

Rapid assessment of heavy metal pollution using ion-exchange resin sachets and micro-XRF core-scanning

Conventional pollution monitoring strategies for heavy metals are often costly and unpractical. Innovative sampling and analytical approaches are therefore needed to efficiently monitor large areas. This study presents a novel, simple, fast, and inexpensive method to monitor heavy metal pollution that uses cation-exchange resin sachets and the micro-XRF core-scanning technique (XRF-CS). The resin passive samplers act as concentrators of cationic species and can be readily deployed spatially and temporally to record pollution signals. The large number of analytical tasks are then overcome by the fast and non-destructive XRF-CS to precisely assess elemental concentrations. Quantifying element loading involves direct comparison with a set of identically prepared and scanned resin reference standards containing Ca, Ti, Cr, Mn, Ni, Cu, Zn, Pb. The results show that within the test range (from 0–1000 s mg kg−1), the calibration lines have excellent regressions (R2 ≥ 0.97), even at the shortest exposure time (1 s). A pilot field survey of a suspected polluted area in central Taiwan, where 30 resin sachets had been deployed, identified a pollution hot spot in a rapid and economical manner. Therefore, this approach has the potential to become a valuable tool in environmental monitoring and forensics.

Fate and removal of antibiotics and antibiotic resistance genes in hybrid constructed wetlands

Hybrid design and artificial aeration has been widely applied in wetlands, but little is known about their effectiveness in the removal of antibiotics and antibiotic resistance genes (ARGs). Here we investigated the performance of various mesocosm-scale constructed wetlands (CWs) with artificial aeration and hybrid design in removal of antibiotics and ARGs from antibiotics-spiked domestic sewage. Four hybrid constructed wetland systems with zeolite as substrate and Iris tectorum Maxim as plant were set up to have different artificial aeration designs. The aqueous removal efficiencies of total antibiotics ranged from 87.4% to 95.3%, while those of total ARGs varied from 87.8% to 99.1%. The mass removal of antibiotics by the CWs was attributed mainly to the microbial degradation. The present study imply that sorption of substrates and biological processes could be the two main mechanisms for ARGs elimination. The results from this study showed the hybrid CWs with artificial aeration could enhance treatment efficiencies of antibiotics and ARGs as well as conventional pollutants.

Seasonal quimiometric study of formaldehyde and acetaldehyde atmospheric levels and health risk assessment, in urban areas of Salvador-Bahia, Brazil

Air pollution affects the health of the population in a number of ways. In 2015, it was responsible for 6.4 million deaths worldwide. Among the aldehydes present in the atmosphere, formaldehyde (HCHO) and acetaldehyde (CH3CHO) are the most abundant ones and they are considered carcinogenic and probably carcinogenic to humans, respectively. The objective of this work was to correlate the concentrations of HCHO and CH3CHO in urban areas of the city of Salvador, in the northeast of Brazil, with levels of concentrations of conventional pollutants and meteorological parameters, and to calculate the risks of the atmospheric levels of these aldehydes to the health of the population. Formaldehyde and acetaldehyde were passively sampled in the air, with 7 days of exposure, using the AnalyzeAr kit in 9 sampling points, in rainy and dry periods. The samples were analyzed by high performance liquid chromatography (HPLC) with UV–Vis detection at 360 nm. The data were submitted to multivariate analysis, applying the principal component analysis (PCA). Formaldehyde and acetaldehyde concentrations ranged from 2.80 to 18.2 μg m−3 from to ≤ LQ (1.19) -16.8 μg m−3, not exceeding in only two places, during the rainy season, the short-term exposure limit (3.3 μg m−3) indicated by the Texas Environmental Quality Commission (USA), which limits this compound in the air at a lower level comparing with other international organizations. The variances of the first three main components together (PC1, PC2 and PC3) described 70.7% of the total data variance, with a tendency to separate the samples according to the seasonality. The average risk of cancer calculated for the local population was (7.2 ± 1.2) × 10−6 and (1.4 ± 0.81) × 10−5 for HCHO and (4.0 ± 1.0) × 10−7 and (2.2 ± 0.16) × 10−6 for CH3CHO, in the rainy and dry periods, respectively, which are above the safety limit established by the US Environmental Protection Agency (1.0 × 10−6) for HCHO in both periods, as well as for CH3CHO in the dry period.

Assessment of metal pollution in groundwater using a novel multivariate metal pollution index in the mining areas of the Singhbhum copper belt

Groundwater samples were collected from 22 locations for 3 seasons in mining areas of Singhbhum copper belt. The concentrations of Al, As, Ba, Co, Cu, Fe, Mn, Ni, V and Zn were evaluated using inductively coupled plasma mass spectrometry to assess the metal pollution using conventional heavy metal pollution index (HPI) and multivariate indexing approaches. Considering all the seasons, metal concentrations exceeded the drinking water standards for Fe and Mn for most of the locations and Al, Cu, Ni and Zn at some of the locations. An assessment using principal component analysis suggested that metals in groundwater in the area are derived from both geogenic and anthropogenic sources. The PCA-based index (PMI) was computed using the factor scores, which does not need any permissible limits or standards for its calculation. A classification of the index is also done using the terciles (3 quantiles) to demarcate the locations into “low”, “moderate” and “high” pollution classes. Marked differences could be identified between the results of HPI and the PCA-based index, of which the latter was found to be robust and more suitable for the study.