Variations in methane (CH₄) and carbon dioxide (CO₂) emissions in municipal sewer driven by pollution sources are complex and multifaceted. It is important to investigate the role of dissolved organic matter (DOM) components and microbiota to better understand what and how those variations occurred. For this purpose, this study provides a systematic assessment based on short-term in-sewer conditioned cultivations, in conjunction with a field survey in four typical sewers in Shanghai Megacity. The results are as follows: (1) Sediment plays a main role in driving the sewer carbon emission behavior owing to its strong associations with the utilized substrates and predominant microbes that significantly promoted the gas fluxes (genera Bacteroidete_vadinHA17, Candidatus_competibacter, and Methanospirillum). (2) Aquatic DOM in overlying water is an indispensable factor in promoting total carbon emissions, yet the dominant microbes present there inversely correlated with gas fluxes (genera Methanothermobacter and Bacteroides). (3) The total fluxes of both CH₄ and CO₂ enhanced by pavement runoff were limited. Its high COD-CH₄/CO₂ conversion efficiencies can be ascribed to its dominant anthropogenic humic-like components and the emerged aquatic tyrosine-like components. (4) Domestic sewage can significantly enhance the total fluxes because of its high concentration of bioavailable DOM. However, these substrates, which were more suitable for supporting microbial growth, as well as the substrate competition caused by sulfate reduction and the nitrogen cycle (revealed by the dominant functional microbes genera Acinetobacter, Pseudomonas, Dechloromona, and Candidatus_competibacter and their correlations with indicators), seemed to be responsible for the low COD-CH₄/CO₂ conversion efficiencies of domestic sewage. (5) A field survey indicated the distinct features of carbon emissions of sewer sewage discharged from different catchments. An extreme hydraulic condition in a sewer in the absence of influent showed unexpectedly high levels of CO₂, while a small amount of CH₄ emissions.

Phoxim, a broad-spectrum organophosphate pesticide, is widely used in agriculture to control insect pests in vegetable crops as well as in farm mammals. However, the indiscriminate use of phoxim has increased its release into the environment, leading to the contamination of plant-based foods such as vegetables. In this study, we investigated the effect of Trichoderma asperellum (TM, an opportunistic fungus) on phoxim residue in tomato roots and explored the mechanisms of phoxim metabolism through analysis of detoxification enzymes and gene expression. Degradation kinetics of phoxim showed that TM inoculation rapidly and significantly reduced phoxim residues in tomato roots. Phoxim concentrations at 5d, 10d and 15d post treatment were 75.12, 65.71 and 77.45% lower in TM + phoxim than only phoxim treatment, respectively. The TM inoculation significantly increased the glutathione (GSH) content, the activity of glutathione S-transferase (GST) and the transcript levels of GSH, GST1, GST2 and GST3 in phoxim-treated roots. In addition, the activity of peroxidase and polyphenol peroxidase involved in the xenobiotic conversion also increased in TM + phoxim treatment. The expression of detoxification genes, such as CYP724B2, GR, ABC2 and GPX increased by 3.82, 3.08, 7.89 and 2.46 fold, respectively in TM + phoxim compared with only phoxim. Similarly, the content of ascorbate (AsA) and the ratio of AsA to dehydroascorbate increased by 45.16% and 57.34%, respectively in TM + phoxim-treated roots. Our results suggest that TM stimulates plant detoxification potential in all three phases (conversion, conjugation and sequestration) of xenobiotc metabolism, leading to a reduced phoxim residue in tomato roots.

Changes in soil nutrients variability could significantly interact with other global change processes (such as community dynamics, biological invasion). Global exchange and accumulation of alien species caused environmental and economic threats in the introduced ranges. Their invasion success or not in local plant communities is largely depended on the interactions and competitive outcomes with other species and environmental conditions. Here, we tested whether the interactions of nutrient variability and competitor identity influence plant performance, potential invasion success of invasive species and their co-existence with native species. In both greenhouse and field experiment, we subjected three congeneric and naturally co-occurring pairs of invasive alien and native clonal plants in China to different nutrient variability (constant high, multiple pulses and/or single pulse) and competitor identity (intra-specific competitors, native competitors, invasive competitors and both native & invasive competitors). Our results showed that total biomass or the increase of cover of invasive species was significantly larger than those of the native species regardless of competitor identity. Native competitors significantly decreased biomass proportion of native species, but did not affect that of invasive species. The whole community with invasive target species accumulated more total biomass than with native species under multiple pulses nutrient when with the native competitors. Invasive species produced significantly higher biomass proportion than natives under all competitor identity treatments except for native & invasive competitors. Multiple mixed competitors (i.e. native & invasive competitors) decreased the plant performance and dominance of invasive target species, to some extent, thus construction of multi-species competition might facilitate coexistence of native and invasive species in communities. Interactions between native competitors or native & invasive competitors, and nutrient variability play important roles in plant performance and potential invasion success in communities. Multiple invasional interference may have significant implications for the co-existence of invasive and native species, and for management of invasive species.

To date limited information’s are available concerning unintentional productions, screening, profiling, and health risks of polychlorinated naphthalenes (PCNs) in ambient environment and occupational environment. Literature reveals that dust is a neglected environmental matrix never measured for PCNs. To our knowledge, this is the first study to investigate the concentrations and health risks of PCNs in indoor dust, air, and blood of major e-waste recycling hubs in Pakistan. Indoor air (n = 125), dust (n = 250), and serum (n = 250) samples were collected from five major e-waste hubs and their vicinity to measure 39 PCN congeners using GC-ECNI-MS. ∑₃₉PCN concentrations in indoor air, dust, and serum (worker > resident > children) samples ranged from 7.0 to 9583 pg/m³, from 0.25 to 697 ng/g, and from 0.15 to 401 pg/g lipid weight, respectively. Predominant PCN congeners in indoor air and dust were tri- and tetra-CNs, while tetra- and penta-CNs were dominant in human serum samples. The higher PCNs contribution was recorded at the recycling units, while the lower was observed at the shops of the major e-waste hubs. Higher contribution of combustion origin CNs in air, dust and human samples showed combustion sources at the major e-waste hubs, while Halowax and Aroclor based technical mixture showed minor contribution in these samples. Mean toxic equivalent (TEQ) concentrations of PCNs were 2.79E⁺⁰⁰ pg-TEQ/m³, 1.60E⁻⁰² ng-TEQ/g, 8.11E⁻⁰¹ pg-TEQ/g, 7.14E⁻⁰¹ pg-TEQ/g, and 6.37E⁻⁰¹ pg-TEQ/g for indoor air, dust, and serum samples from workers, residents, and children, respectively. In our study, CNs- 66/67 and −73 in indoor air, dust, and human serum were the great contributors to total TEQ concentrations of PCNs. This first base line data directs government and agencies to implement rules, regulation to avoid negative health outcomes and suggests further awareness in regard of provision of proper knowledge to the target population.

The objectives of this research are: identify the hydrocarbons in water from the Bitzal River, Tabasco; select a carbon source that serves as a representative substrate of the determined compounds; and finally, design an experimental proposal for bioreactors that are capable of consuming compounds formed by complex mixtures and, therefore be effective in the elimination of specific hydrocarbons. We identified 16 compounds that belong to different hydrocarbon fractions. Pentacene (24.3 ± 0.09 mg L⁻¹), n-nonane (2.11 ± 0.96 mg L⁻¹) and benzo [a] pyrene (1.39 ± 0.57 mg L⁻¹) were the compounds with the highest concentrations in water. Two culture media, mineral medium and seawater were used. Diesel and Mayan crude oil were used for each culture medium, with a total of four bioreactors. Diesel represented light- and medium-fraction hydrocarbons, while Mayan crude oil represented the heavy fraction as well as the recalcitrant and polycyclic aromatic hydrocarbons (PAH). The maximum growth of suspended solids for diesel in mineral medium reached 2.95 g L⁻¹, and diesel was completely consumed in 8 days. In seawater, suspended solids for diesel reached 2.70 g L⁻¹, and diesel was consumed in 12 days. For Mayan crude oil in mineral medium, suspended solids increased from 0.8 to 2.41 g L⁻¹, and Mayan crude oil was completely consumed in 12 days. Using seawater, Mayan crude oil also degraded in 12 days, and suspended solids growth reached 2.11 g L⁻¹. Compounds that simulate complex mixtures of hydrocarbons from light to heavy fractions could be degraded, and the use of bioreactors is an alternative method of hydrocarbon pollution remediation in the Bitzal River.

Fungi have an exceptional capability to flourish in presence of heavy metals and pesticide. However, the mechanism of bioremediation of pesticide (lindane) and multimetal [mixture of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn)] by a fungus is little understood. In the present study, Aspergillus fumigatus, a filamentous fungus was found to accumulate heavy metals in the order [Zn(98%)>Pb(95%)>Cd(63%)>Cr(62%)>Ni(46%)>Cu(37%)] from a cocktail of 30 mg L⁻¹ multimetal and lindane (30 mg L⁻¹) in a composite media amended with 1% glucose. Particularly, Pb and Zn uptake was enhanced in presence of lindane. Remarkably, lindane was degraded to 1.92 ± 0.01 mg L⁻¹ in 72 h which is below the permissible limit value (2.0 mg L⁻¹) for the discharge of lindane into the aquatic bodies as prescribed by European Community legislation. The utilization of lindane as a cometabolite from the complex environment was evident by the phenomenal growth of the fungal pellet biomass (5.89 ± 0.03 g L⁻¹) at 72 h with cube root growth constant of fungus (0.0211 g¹/³ L⁻¹/³ h⁻¹) compared to the biomasses obtained in case of the biotic control as well as in presence of multimetal complex without lindane. The different analytical techniques revealed the various stress coping strategies adopted by A. fumigatus for multimetal uptake in the simultaneous presence of multimetal and pesticide. From the Transmission electron microscope coupled energy dispersive X-ray analysis (TEM-EDAX) results, uptake of the metals Cd, Cu and Pb in the cytoplasmic membrane and the accumulation of the metals Cr, Ni and Zn in the cytoplasm of the fungus were deduced. Fourier-transform infrared spectroscopy (FTIR) revealed involvement of carboxyl/amide group of fungal cell wall in metal chelation. Thus A. fumigatus exhibited biosorption and bioaccumulation as the mechanisms involved in detoxification of multimetals.

In order to determine the current levels, spatial distribution patterns, and potential pollution of trace elements (TEs) in the atmosphere of the Tibetan Plateau (TP), snow pit samples were collected in May 2016 from five TP glaciers: Qiyi (QY), Hariqin (HRQ), Meikuang (MK), Yuzhufeng (YZF), and Xiaodongkemadi (XDKMD). Concentrations of 13 TEs (Al, Ba, Cd, Co, Cr, Cu, Fe, Li, Pb, Sb, Sr, U, and Zn) in the snow were measured. The spatial distribution patterns and depth profiles of TEs from the studies sites revealed that the influence of dust on TEs was more significant on the MK and YZF glaciers than on the QY, HRQ, and XDKMD glaciers. The spatial distributions of TE EFFₑ values differed from their concentrations, however. The enrichment factor (EF) values and concentrations of some TEs in the YZF, QY, and XDKMD glaciers revealed that the pollution levels of these elements were significantly lower than those found in previous research. Examination based on EFs, principal component analysis, as well as the calculated non-dust contributions of TEs, revealed that dust was the principal source for most TEs in all five glaciers, while biomass burning was another potential natural source for TEs in some glaciers, such as QY. In contrast, Cd, Ba, Sr, Cu, Pb, Zn, and Sb were occasionally affected by anthropogenic sources such as road traffic emissions, fossil fuel combustion, and mining and smelting of nonferrous metals in and beyond the TP. Air mass backward trajectories revealed that potential pollutants were transported not only from local sources but also from Xinjiang Province in northwestern China, as well as South Asia, Central Asia, the Middle East, and Europe.

Inland waters emit large amounts of carbon dioxide (CO₂) to the atmosphere, but emissions from urban lakes are poorly understood. This study investigated seasonal and interannual variations in the partial pressure of CO₂ (pCO₂) and CO₂ flux from Lake Wuli, a small eutrophic urban lake in the heart of the Yangtze River Delta, China, based on a long-term (2000–2015) dataset. The results showed that the annual mean pCO₂ was 1030 ± 281 μatm (mean ± standard deviation) with a mean CO₂ flux of 1.1 ± 0.6 g m⁻² d⁻¹ during 2000–2015, suggesting that compared with other lakes globally, Lake Wuli was a significant source of atmospheric CO₂. Substantial interannual variability was observed, and the annual pCO₂ exhibited a decreasing trend due to improvements in water quality driven by environmental investment. Changes in ammonia nitrogen and total phosphorus concentrations together explained 90% of the observed interannual variability in pCO₂ (R² = 0.90, p < 0.01). The lake was dominated by cyanobacterial blooms and showed nonseasonal variation in pCO₂. This finding was different from those of other eutrophic lakes with seasonal variation in pCO₂, mostly because the uptake of CO₂ by algal-derived primary production was counterbalanced by the production of CO₂ by algal-derived organic carbon decomposition. Our results suggested that anthropogenic activities strongly affect lake CO₂ dynamics and that environmental investments, such as ecological restoration and reducing nutrient discharge, can significantly reduce CO₂ emissions from inland lakes. This study provides valuable information on the reduction in carbon emissions from artificially controlled eutrophic lakes and an assessment of the impact of inland water on the global carbon cycle.

The Gulf of Mexico (GoM) is exposed to a diversity of contaminants, such as hydrocarbons and heavy metal(oid)s, either from natural sources or as a result of uncontrolled coastal urbanisation and industrialisation. To determine the effect of these contaminants on the marine biota along the Mexican GoM, the biological responses of the shoal flounder Syacium gunteri, naturally exposed, were studied. The study area included all the Mexican GoM, which was divided into three areas: West-southwest (WSW), South-southwest (SSW) and South-southeast (SSE). The biological responses included the global DNA methylation levels, the expression of biomarker genes related to contaminants (cytochrome P450 1A, glutathione S-transferase, glutathione reductase, glutathione peroxidase, catalase, and vitellogenin), histopathological lesions and PAH metabolites in bile (hydroxynaphthalene, hydroxyphenanthrene, hydroxypyrene and Benzo[a]pyrene). The correlation between the biological responses and the concentration of contaminants (hydrocarbons and metal(oid)s), present in both sediments and organisms, were studied. The shoal flounders in WSW and SSW areas presented higher DNA hypomethylation, less antioxidative response and biotransformation gene expression and a higher concentration of PAH metabolites in bile than SSE area; those responses were associated with total hydrocarbons and metals such as chromium (Cr). SSE biological responses were mainly associated with the presence of metals, such as cadmium (Cd) and copper (Cu), in the tissue of shoal flounders. The results obtained on the physiological response of the shoal flounder can be used as part of a permanent active environmental surveillance program to watch the ecosystem health of the Mexican GoM.

Cell wall acts as a major metal sink in plant roots, while a few studies focused on root cell wall binding in plants for the phytostabilization of multi-metal contaminated soils. A pot experiment was performed to characterize root cell wall properties of the mining ecotype (ME) and non-mining ecotype (NME) of Athyrium wardii (Hook.) in response to Cd and Pb. The cell wall was found to be the major sink for Cd (41.3–54.3%) and Pb (71.4–73.8%) accumulation in roots of the ME when exposed to Cd and/or Pb. The ME showed more Cd and Pb accumulation in root cell walls when exposed to Cd and Pb simultaneously, compared with those exposed to single Cd or Pb as well as the NME, suggesting some modifications for cell walls. The uronic acid contents of pectin and hemicellulose 1 (HC1) in root cell walls of the ME increased significantly when exposed to Cd and Pb simultaneously, suggesting enhanced cell wall binding capacity, thus resulting in more Cd and Pb bound to pectin and HC1. In particular, pectin was found to be the predominant binding site for Cd and Pb. Greater pectin methylesterase activity along with a lower degree of methylesterification were observed in the cell walls of the ME when exposed to Cd and Pb simultaneously. Furthermore, the ME present more O–H, N–H, C–OH, C–O–C, C–C and/or Ar–H in root cell walls when exposed to Cd and Pb simultaneously. These changes of root cell wall properties of the ME lead to enhanced cell wall binding ability in response to the co-contamination of Cd and Pb, thus could be considered a key process for enhanced Cd and Pb accumulation in roots of the ME when exposed to Cd and Pb simultaneously.