In the original publication, the given name of the fourth author was mispelled as Adolp instead of Adolph. The correct name of the fourth author is Adolph Anga Muleja.

In this study, we investigated the effect of acute administration of gold nanorods (AuNRs) on testicular function, sexual hormones, and oxidative stress parameters in male albino rats. Forty mature male albino rats were divided into two equal groups (n = 20/each). The first group received 1 ml saline solution intraperitoneally (i.p.). The second group received single i.p. injection of 75 μg 50 nm AuNRs/kg/bwt. Five rats from each group were sacrificed on days 1, 3, 7, and 14 post treatment and blood samples were collected for hormonal and biochemical analysis. Testes were collected from each group at each time point for histopathology, morphometric, and transmission electron microscope analyses of testis and epididymis. Results indicated that i.p. injection of AuNRs did not produce any histopathological changes. Morphometric analysis of testicular samples revealed that the height of lining epithelium was significantly (P < 0.05) higher in AuNR group on days 3 and 14 post treatment, and the minor axis of seminiferous tubules was higher (P < 0.05) in AuNR-injected rats than in control group. For the epididymis, the number of spermatozoa was significantly (P < 0.05) higher on days 7 and 14 after AuNR injection when compared with control rats. AuNRs were not detected by TEM at all time points of the experiment. Serum analysis demonstrated that total and free testosterone values significantly (P < 0.05) increased on days 1, 3, 7, and 14 post AuNR injection. LH was higher (P < 0.05) in AuNRs-injected rats on days 3, 7, and 14 post injection, while FSH values were higher (P < 0.05) in AuNR group on days 3 and 14. Malondialdehyde significantly (P < 0.05) decreased on days 3, 7, and 14 in AuNR group, while catalase, glutathione peroxidase, and superoxide dismutase values were significantly (P < 0.05) elevated on days 3, 7, and 14 in AuNRs-injected rats compared with control group. In conclusion, intraperitoneal injection of 50 nm AuNRs is safe on the reproductive function and has an antioxidant action.

Management procedures (MPs) based on data-limited methods (DLMs) recently developed to give management advices for data-limited stocks worldwide are scarce or yet to be implemented on freshwater species. In this study, case studies (CSs) were developed using length-frequency data (LFD) of common carp species harvested from Dianshan Lake to estimate life-history parameters from existing methods. These CSs were later used to examine their influences when tested with various MPs under scenarios when operating models (OMs) were subjected to observation and estimation uncertainties. The results after management strategy evaluation (MSE) was run for various defined OMs showed that three MPs emerged best for providing managing advice. For high yield to be maintained during short-term periods, MinlenLopt1 suggested the smallest length at full retention (sLFR) to be 42.11 cm; while Slotlim and matlenlim2 suggested that to maintain biomass and stable spawning biomass (SBMSY) and also avoid overfishing from occurring in this fishery, sLFR should be 56.1 cm. Values given by these MPs allowed the removal of species that spawned at least once. Also, life-history parameters derived from CS4 presented the best results, being more reliable in presenting better inputs for effective management of the said fishery.

The efficient removal of heavy metals from aqueous environment is imperative and challenging. A novel ternary composite constructed of diaminopyridine polymers, graphene oxide, and ferrite magnetic nanoparticles was designed by a facile in situ polymerization strategy for the removal of Pb(II) from aqueous solution. Detailed characterization of morphological, chemical, and magnetic properties was employed systematically to confirm the formation of the composite material. Batch adsorption experiment studies suggested that the composite was an excellent adsorbent for Pb(II) which was easily collected after use via exposure to an external magnetic field for 30 s. The effects of different parameters such as solution pH, adsorbent dosage, contact time, initial Pb(II) concentration, temperature, and co-existing ions were examined. The maximum adsorption capacity at pH = 5 was estimated to be 387.2 mg g⁻¹ at 298 K by the Langmuir isotherm model, accompanied by favorable adsorption recyclability according to the investigation of regeneration experiments. Thermodynamic studies revealed that the Pb(II) adsorption via our ternary composite was endothermic and spontaneous. The corresponding removal performance for effluent containing Pb(II) from the battery industry was successfully examined. The present results indicated that our designed adsorbent is beneficial to the practical Pb(II) removal in wastewater purification.

The composition of SrCuₓO mixed metal oxides (MMOs) was engineered via varying the amount of copper relative to strontium. As-synthesized SrCuₓO were highly active for degrading methyl orange (MO) pollutant at dark ambient conditions without the aid of other reagents. The catalytic activity of SrCuₓO demonstrated a reverse-volcano relationship with copper content. Copper-rich MMOs (SrCu₂O) exhibited the highest degradation activity for MO by far and degraded ca. 96% MO within 25 min. MO degradation over SrCu₂O was a surface-catalytic reaction and fitted pseudo-first-order reaction kinetics. The contact between MO molecules and catalyst surface initiated the reaction via the catalytic-active phase (Cu⁺/Cu²⁺ redox pair), which serves as an electron-transfer shuttle ([Formula: see text]) from MO to dissolved O₂, inducing the consecutive generation of reactive oxygen species, which resulted in MO degradation as evidenced by radical trapping experiment. XPS and XRD analysis revealed that active phases in SrCu₂O materials underwent irreversible transformation after reaction, contributing to the observed deactivation in the cycling experiment. The observations in this study demonstrate the significance of chemical composition tailoring in catalyst synthesis for environmental remediation under dark ambient conditions. Graphical abstract

This study investigated the soil pollution level and evaluated the phytoremediation potential of 25 native plant species on a former gold mine-tailing site in Ghana. Plant shoots and associated soil samples were collected from a tailing deposition site and analyzed for total element concentration of As, Hg, Pb, and Cu. Soil metal(loid) content, bioaccumulation factor (BAFₛₕₒₒₜₛ), and hyperaccumulator thresholds were also determined to assess the current soil pollution level and phytoextraction potential. The concentration of As and Hg in the soil was above international risk thresholds, while that of Pb and Cu were below those thresholds. None of the investigated plant species reached absolute hyperaccumulator standard concentrations. Bioavailability of sampled metal(loid)s in the soil was generally low due to high pH, organic matter, and clay content. However, for Cu, relatively high bioaccumulation values (BAFₛₕₒₒₜₛ > 1) were found for 12 plant species, indicating the potential for selective heavy-metal extraction via phytoremediation by those plants. The high levels of As at the study site constitute an environmental and health risk but there is the potential for phytoextraction of Cu (e.g., Aspilia africana) and reclamation by afforestation using Leucaena leucocephala and Senna siamea.

Despite the controversy, the ecological risk of microplastics research has increased sharply from only one in 1966 to 495 in 2018, according to Web of Science with microplastics as keyword. To date, an upward trend of global microplastics mass emission was confirmed by many environmental scientists. The ocean is the ultimate destination of land-based microplastics sources; therefore, most of efforts were concentrated on microplastics in aquatic environment. In this brief article, the global release of microplastics and flux into the ocean in the recent decade were estimated roughly. The plastics fragmentation in the marine environment only accounted for 22% of total microplastics release (assuming defined emission rate per capita and fragmentation rate of plastics). Future research is needed for microplastics generation and retention in the terrestrial system, especially indoor environments. The accumulated microplastics over the environmental self-purification capacity certainly increases stress for the marine, freshwater and terrestrial ecosystem.

Rapid detection of oil released from underground storage tanks and estimation of its flow rate allows for the prevention of further contamination or the limitation of the spread of contaminants. In this research, we developed a method for oil release detection by sensing volumetric water contents (VWC) in a hydraulic control system. Oil release detection tests were conducted at bench and pilot scales. In the bench-scale test, oil and water were released directly on top of the oil release detection system. In the pilot-scale test, the release detection system was installed in the soil and the oil was spilled on the soil surface. The new oil release monitoring system was capable of detecting the oil release using the VWC decrease (0.42 → 0.11 m³/m³). The infiltration of water did not affect the value of VWC. Sequential injection or mixture of oil and water also showed a decrease in VWC (0.42 → 0.12 m³/m³). The rate of VWC decrease was directly proportional (− 0.003 ml/min) to the rate of oil infiltration. A conceptual model was suggested to delineate the mechanism of oil release detection and to estimate the rate of oil infiltration. The detectability of the oil release in soil was also verified in the pilot-scale test (0.45 → 0.12 m³/m³). The rate of oil infiltration could be estimated using the slope of the measured VWC. The amount of time for oil infiltration through the soil and dispersion during the migration should be considered to analyze the VWC curve properly. These results showed that the oil release detection system can be used to monitor oil release and to determine the rate of oil infiltration by installation in the soil near an underground storage tank.

Mires and peatlands in general are heavily influenced by anthropogenic stressors like acidification, eutrophication, desiccation and fragmentation. Groundwater-fed mires are, in contrast to rainwater-fed mires, often well protected against desiccation due to constant groundwater discharge. Groundwater-fed mires can however be influenced by groundwater pollution such as groundwater nitrate enrichment, a threat which has received minor attention in literature. The present case study demonstrates how groundwater nitrate enrichment can affect the biogeochemical functioning and vegetation composition of groundwater-fed mires through direct nitrogen enrichment and indirect nitrate-induced sulphate mobilisation from geological deposits. Biogeochemical and ecohydrological analyses suggest that the Dutch groundwater-fed mire studied is influenced by different water sources (rainwater; groundwater of local and regional origin) with differing chemical compositions. The weakly buffered and nitrate-enriched groundwater leads, where it reaches the uppermost peat, to nitrogen enrichment, enhanced isotopic nitrogen signatures and altered the vegetation composition at the expense of characteristic species. Nitrate-induced sulphate mobilisation in the aquifer led to enhanced sulphate reduction, sulphide toxicity and elemental sulphur deposition in the mire. Despite sulphate reduction and nitrate enrichment, internal eutrophication did not play an important role, due to relatively low phosphorus concentrations and/or low iron-bound phosphorus of the peat soil. Future management of groundwater-fed mires in nitrate-polluted aquifers should include the reduction of nitrate leaching to the aquifer at the recharge areas by management and ecohydrological restoration measures on both a local and landscape scale.

San Juan de los Planes agricultural valley (SJPV) was studied to determine the pollution of the soils and the source of the pollutants, and revise possible ecological risks and health risks for the inhabitants due to the presence of these elements. On average, the total concentration order was As > Zn > Cu > Co > Cd. A multivariate analysis was made to identify the source of the elements and a correlation analysis to relate the concentrations and soil properties. Seven geochemical indices, two ecotoxicological, and two health risk indices were estimated. The enrichment factor (EF) showed minor or no enrichment, and the geoaccumulation index (Igeo) defined the valley as uncontaminated to moderately contaminated. The contamination factor (Cf), contamination degree (CD), and modified contamination degree (mCD) showed low or moderate contamination. The pollution load index (PLI) and comprehensive pollution index (Pn) indicated that four sites are moderately to seriously polluted with As and Cd. The potential ecological risk factor (Er) classified the area with a low potential, and the potential ecological risk index (RIEc) resulted as low ecological risk for 87% of the sites. The hazard index (HI) revealed that the contents of As and Cd can cause non-carcinogenic health problems and the carcinogenic risk index (RI) showed that As is a potential threat to the inhabitants. Given that the pollution with As and Cd is occurring in only four of the sites and that they were correlated with silt fraction, it can be said that this is related to the agrochemicals and not from the mining activities uphill.