Availability of lead (Pb) in soil is a major factor controlling the phytoremediation efficiency of plants. This study was focused on investigating the plant-induced changes in rhizosphere and corresponding effect on bioavailable fraction of Pb and accumulation in different plant parts. For rhizosphere study, special cropping device was designed locally. Two Pb accumulator plants Stigmatocarpum criniflorum (L. f.) L. Bolus and Pelargonium × hortorum L.H. Bailey were grown in cropping device setup containing Pb spiked soil (500, 1000, 1500, and 2000 mg kg⁻¹) for a period of 3 weeks. Further plants were also analyzed for Pb-induced oxidative stress. The results indicated higher ability of soil adjustment for Pb uptake by P. hortorum. The soil pH was (p < 0.05) decreased (ΔpH = − 0.22 pH), and dissolved organic carbon (DOC) content was significantly increased (by 1.7-fold) in rhizosphere of P. hortorum. The bioavailable fraction of Pb was twofold higher in rhizosphere of P. hortorum than S. criniflorum at the same soil Pb concentration (2000 mg kg⁻¹). Maximum Pb concentration in root and shoot of S. criniflorum was 755 ± 99 and 207 ± 12 mg Pb/kg DW and for P. hortorum was 1281 ± 77 and 275 ± 7 mg Pb/kg DW. P. hortorum uptakes more Pb per plant by threefold compared with S. criniflorum. The oxidative stress results indicated higher Pb tolerance and suitability of P. hortorum for phytoextraction of Pb-contaminated soil.

Phytoplankton and bacterioplankton perform important ecological functions in lake ecosystem. In this paper, the abundance and composition of phytoplankton and bacterioplankton at 13 sites of Dianchi lake during the wet and dry seasons were monitored, and the relationship between phytoplankton and bacterioplankton in this plateau lake was studied. Phytoplankton community structure analysis was carried out by ocular method, and bacterioplankton was investigated by high-throughput 16S rRNA gene Illumina sequencing. The relationship between phytoplankton and bacterioplankton was observed using redundancy analysis. The results showed that 87 species of phytoplankton belonging to 5 phyla and 29 genera were identified in Dianchi lake. Phytoplankton diversity and richness were higher in the wet season than those in the dry season. In the wet season, Cyanophyta was the dominant phylum whose density was 2.01 × 10⁸ cells/L, accounting for more than 90% of the total algae, then followed by Chlorophyta, Bacillariophyta, Chrysophyta, and Cryptophyta. The spatial distribution of phytoplankton in the wet season and dry seasons showed significant differences. In the dry season, the north-central part of Dianchi lake was dominated by Limnothrix redekei and Microcystis minutissima of Cyanophyta, while Pseudanabaena moniliformis and Coelosphaerium nagelianum of Cyanophyta mainly was dominated in the south of Dianchi lake. In the wet season, Microcystis minutissima of Cyanophyta was the dominant species all the area, while Limnothrix redekei of Cyanophyta was second dominant. Proteobacteria and Bacteroidetes were the dominant phyla among bacterioplankton. The community structure of bacterioplankton was influenced by Cyanophyta and Bacillariophyta. Cyanophyta had a major influence on Pseudomonas, Acinetobacter of Proteobacteria, and Flavobacterium of Bacteroidetes. Bacillariophyta showed a strong correlation with Gemmobacter, Stenotrophomonas, and Aeromonas of Proteobacteria. Cyanophyta and Bacillariophyta produced the most significant impact on predicted functional genes of bacterioplankton, and the predicted functional genes of the samples were different in different seasons. Cell densities of Cyanophyta were positively related to metabolism-predicted functional genes of bacterioplankton. Bacillariophyta and Cryptophyta had an impact on most of the cellular processes and signaling predicted functional genes. Bacterioplankton-predicted functional gene information storage and processing were significantly affected by cell densities of Chlorophyta. Therefore, the analysis of the phytoplankton community and the bacterioplankton-predicted functional gene in Dianchi lake exerts a great significance in revealing the ecosystem function of plateau lakes and harmful algal bloom control.

Nowadays, veterinary drug application has become an integral practice in livestock farming. Veterinary antibiotics (VAs) are administered onto animals for therapeutic use; meanwhile, in some countries, they are used for growth promotion. To indicate the level of VAs use in livestock breeding in two countries, Albania and Kosovo, their presence was studied in the animal manure. In total, 38 manure samples, 22 from Kosovo and 16 samples from Albania, belonging to cattle, pig, and poultry, were collected and investigated for the presence of VAs. Seven VAs and 2 metabolites, from the groups of sulfonamides and tetracyclines, were identified by ultra-high pressure liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The detected antibiotics were sulfadiazine (SDZ), sulfathiazole (STZ), sulfamethazine (SMZ), oxytetracycline (OTC), tetracycline (TC), chlortetracycline (TC), and doxycycline (DOY). VAs were detected in 27% and 31.2% of the manure samples, from Kosovo and Albania, respectively, and the levels ranged from 0.04 to 10.1 mg kg⁻¹. VAs were widely detected (100%) in poultry manure from Kosovo, as well as poultry manure from Albania. The contamination rate ranged from pig manure (25%) to cow manure (66.6%). Sulfonamides were the most commonly detected VAs with maximum concentration of sulfadiazine (10.1 mg kg⁻¹) in poultry manure. Tetracyclines were most widely detected in poultry manure, as well as other animal manures. When it comes to the comparison between the two countries, VAs residues are more frequent per analyzed sample and higher in concentrations in the manure samples from Albania. Therefore, an environmental impact of VAs on both countries may be expected. These results indicate that VAs may enter the local ecosystem through manure application to agriculture and potentially may bring ecological risks.

Rare earth elements (REEs) have been widely used in recent decades, and their exploitation has led to industrial REE emission and to contaminated soils especially in former mining areas. This raised people concerns on the accumulation and toxicity of REEs in soils and plants, and consequences on plant health. Although many studies dealt with REE in soils and plants, there is still a need to precise their toxicity, bioavailability and transfer to plants in contaminated sites in order to restore such ecosystems. We studied the bioavailability and transfer of a REE to Medicago sativa grown on two contaminated soils differing in their chemical characteristics. A pot experiment was set up in a growth chamber where two natural soils were spiked or not with samarium (Sm) as a model REE. Two chemical extractants were tested to estimate the bioavailability of Sm in the soil, its decrease with time and its transfer to the plants. Results showed that DTPA extractable Sm was well correlated with Sm uptake in alfalfa shoots. The experiment pointed out a significant ageing effect since DTPA extractable Sm significantly decreased within 2 weeks in the soils and was significantly lower in the less acidic soil than in the other. The uptake of Sm from soil to alfalfa shoots depended on the soil pH and on the spiking concentration. The soil to plant transfer factor was low (< 0.08), but a 30% reduction of alfalfa biomass was observed when the soils were spiked with 100 to 200 mg kg⁻¹ of Sm.

Fishery byproducts were acidogenically fermented with agricultural wastes (corncob, cabbage waste, and fruit peel), and fishery acidogenic fermentation broth (FFB) was used to observe sludge reduction and biogas production in anaerobic co-digestion. The experiment was conducted using a batch test for 30 days in mesophilic conditions. Samples with FFB showed a short response delay time of 1.50–3.06 (day), and total solid (TS) and volatile solid (VS) removal efficiencies of 23–43% and 20–30%, respectively, which were higher than those without FFB. In addition, the process produced 2.63–3.86 times more biogas with a methane content of over 70%. These results indicate that FFB improves the biodegradability of sewage sludge and that microbial communities were activated in a short time during the anaerobic co-digestion process. In particular, the highest TS and VS removal efficiency, biogas production, and high methane content were observed in FFB with corncobs. This suggests that nutrients such as sugar and minerals in corncobs may have positively affected the activity of methane-producing archaea. The anaerobic co-digestion process, which combines FFB and sewage sludge, enhanced the treatment efficiency of sludge and has an advantage of energy recovery.

Zoige alpine peatland as the highest and largest peat swamp area in the world plays an important role in regulating global climate change and stabilizing GHG emissions, and GHG emissions are getting more and more concern due to water table decline induced by the combined effects of climate warming and digging ditches in Zoige alpine peatland. Therefore, emissions of CH₄, CO₂, and N₂O were investigated in situ along different water table transects in Zoige peatland. Results showed that the CO₂ and N₂O fluxes increased along the reduced water table gradient except the lowest water table sites, while CH₄ flux was decreased. Meanwhile, the global warming potential decreased from 798.6 to 430.9 g CO₂ eq m⁻ ² h⁻ ¹ with the declined water table. Stepwise multiple regression analysis demonstrated that SOC was the primary factor explaining the variations of CO₂ and N₂O fluxes across different water table levels, and soil water content was the most important factor to explain the CH₄ flux. Water table was the primary driver to determine the GHG fluxes, and the CO₂ and N₂O emissions were also dependent on the SOC variations. Overall, our results would be beneficial to understand the mechanism of water table effect on GHG emission in alpine peatland ecosystem and provide supports for alpine peatland management in the future.

This paper employs a recently constructed consumption-based carbon dioxide emissions data in which emissions computations are made based on fossil fuel usage domestically, in addition to emissions emanating from imports minus exports. We contrast this measure with the commonly measured territory-based carbon dioxide emissions data and examine how trade performance (split into imports, exports, and total trade) impacts these two measures of carbon dioxide. We focus on 22 sub-Saharan African countries over the period 1995–2014. Employing the system generalized method of moments, we find trade to generally have positive effect on emissions. The results are consistent across the different measures of trade and carbon dioxide emissions. The results of the paper allow us to give some policy suggestions regarding carbon dioxide emissions in sub-Saharan Africa.

To investigate the potential pollution risk of permeable brick paving systems in areas with high groundwater levels, a system was constructed by using ceramic permeable bricks as the surface and a Chinese character “well”-shaped frame as the base on the top of a 1.0 m clay layer. The concentrations of total suspended solids (TSS), total phosphorus (TP), ammonia nitrogen (NH₄⁺-N), total nitrogen (TN), chemical oxygen demand (COD), and heavy metals (Zn, Cu, and Pb) at different underground depths were measured, the potential pollution of the groundwater was assessed, and the effectiveness of the fillers inside the frame for improving the quality of the groundwater was discussed. The results showed that NH₄⁺-N and COD concentrations detected at the depth of 0.6 m were higher than that of the national standard for groundwater (GBT14848-2017), these two pollutants had the potential pollution risk. The pollution risk by heavy metals was comparatively low because most of the heavy metals were likely retained in the surface soil by adsorption, complexation, and precipitation, while the pollution risk by TSS and TP was negligible due to the good purification ability in the clay layer. The results suggest that the removal rates of TSS, TP, TN, COD, and heavy metals can be improved by appropriate fillers’ adjustment, such as iron filings, coal slag, or volcanic rocks. This research offers a new perspective on the potential risk of pollution and the governance of groundwater.

In this study, a pre-isolated dye-decolorizing bacterium, Pseudomonas aeruginosa ZM130, was tested to explore its potential for the treatment of synthetic and real textile wastewaters in aerobic and anaerobic bench-scale sequencing batch bioreactors (SBRs) as well as in constructed soil columns. The decolorizing ability of strain ZM130 against reactive black-5 (RB5) was optimized following a response surface methodology (RSM)-based approach, and this strain was observed to effectively decolorize RB5 even in presence of a substantial quantity of NaCl salt along multi-metal mixture including Cr⁶⁺, Pb²⁺, Cd²⁺, and Zn²⁺. In the SBR containing the immobilized cells of the strain ZM130, more than 80% of the RB5, hexavalent chromium [Cr(VI)], and chemical oxygen demand (COD) were removed from the textile wastewater under partially anaerobic condition using yeast extract as an additional carbon co-substrate. Furthermore, while studying the bioremediating ability of strain ZM130 in constructed soil columns, the maximum color removal (> 90%), Cr(VI) removal (> 95%), and COD removal (> 90%) were achieved in the soil columns bioaugmented with ZM130 together with either sludge or yeast extract. Interestingly, it was further noticed that soil columns augmented with P. aeruginosa ZM130 also showed maximum color removal from real textile wastewater in vertical columns filled with sterilized (> 87%) and non-sterilized soil (> 91%). Based on the results of the present research work, it can be concluded that P. aeruginosa ZM130 can serve as an excellent potential candidate for treatment of textile wastewaters in bioreactors as well as in soils.

Petroleum-industry wastewater (PI-WW) is a potential source of water that can be reused in areas suffering from water stress. This water contains various fractions that need to be removed before reuse, such as light hydrocarbons, heavy metals and conditioning chemicals. Constructed wetlands (CWs) can remove these fractions, but the range of PI-WW salinities that can be treated in CWs and the influence of an increasing salinity on the CW removal efficiency for abovementioned fractions is unknown. Therefore, the impact of an increasing salinity on the removal of conditioning chemicals benzotriazole, aromatic hydrocarbon benzoic acid, and heavy metal zinc in lab-scale unplanted and Phragmites australis and Typha latifolia planted vertical-flow CWs was tested in the present study. P. australis was less sensitive than T. latifolia to increasing salinities and survived with a NaCl concentration of 12 g/L. The decay of T. latifolia was accompanied by a decrease in the removal efficiency for benzotriazole and benzoic acid, indicating that living vegetation enhanced the removal of these chemicals. Increased salinities resulted in the leaching of zinc from the planted CWs, probably as a result of active plant defence mechanisms against salt shocks that solubilized zinc. Plant growth also resulted in substantial evapotranspiration, leading to an increased salinity of the CW treated effluent. A too high salinity limits the reuse of the CW treated water. Therefore, CW treatment should be followed by desalination technologies to obtain salinities suitable for reuse. In this technology train, CWs enhance the efficiency of physicochemical desalination technologies by removing organics that induce membrane fouling. Hence, P. australis planted CWs are a suitable option for the treatment of water with a salinity below 12 g/L before further treatment or direct reuse in water scarce areas worldwide, where CWs may also boost the local biodiversity. [Figure not available: see fulltext.]