The high pollutants loading of road-deposited sediment (RDS) make it the main threat to receiving water bodies in stormwater management; however, the characteristics of RDS have not yet been sufficiently studied. In this study, samples were collected from three different land-use type areas (campus, residential, and commercial) in Beijing, China, and analyzed for particle size distribution, chemical compositions, and dissolution characteristics. The results revealed that RDS in the sampling sites mainly consisted of particles < 63 μm, which accounted for 40.3%, 30.5%, and 30.3% of the total in samples from campus, residential, and commercial sites, respectively. In addition, the mass percentage of sediments decreased with increasing particle size in all three sampling sites. The highest pollutants loading were mainly found in particles between 125 and 250 μm. The pollutant loading occurred in the following order: commercial > residential > campus for COD and heavy metals (Cr, Cd, Pb, Cu), and campus > residential > commercial for TN, NH₄⁺-N, and PO₄³⁻-P. The pollutants dissolved capacity (DC) and pollutants dissolved velocity (DV) both decreased with increasing particle size. Overall, the results of this study highlight the importance of removing fine particles to controlling road runoff pollution.

The ingestion of microplastics (MPs) is well documented for various animals and spherical MPs (beads) in many studies. However, the retention time and egestion of MPs have been examined less, especially for irregular MPs (fragments) which are predominantly found in the environment. Furthermore, the accumulation of such particles in the gastrointestinal tract is likely to determine whether adverse effects are induced. To address this, we investigated if the ingestion and egestion of beads are different to those of fragments in the freshwater shrimp Neocaridina palmata. Therefore, organisms were exposed to 20–20,000 particles L⁻¹ of either polyethylene (PE) beads (41 μm and 87 μm) or polyvinyl chloride (PVC) fragments (<63 μm). Moreover, shrimps were exposed to 20,000 particles L⁻¹ of either 41 μm PE and 11 μm polystyrene (PS) beads or the PVC fragments for 24 h, followed by a post-exposure period of 4 h to analyze the excretion of particles. To simulate natural conditions, an additional fragment ingestion study was performed in the presence of food. After each treatment, the shrimps were analyzed for retained or excreted particles. Our results demonstrate that the ingestion of beads and fragments were concentration-dependent. Shrimps egested 59% of beads and 18% of fragments within 4 h. Particle shape did not significantly affect MP ingestion or egestion, but size was a relevant factor. Medium- and small-sized beads were frequently ingested. Furthermore, fragment uptake decreased slightly when co-exposed to food, but was not significantly different to the treatments without food. Finally, the investigations highlight that the assessment of ingestion and egestion rates can help to clarify whether MPs remain in specific organisms and, thereby, become a potential health threat.

This work examines the effect of ultrasound irradiation (UI) on biodiesel properties and transesterification parameters. Methanol content, reaction time, reaction temperature, and catalyst concentration are varied, and the optimum condition for maximum possible yield was held constant for both processes. Biodiesel obtained from non-edible oils is the most promising alternative fuel for conventional diesel fuel. In this study, sterculia foetida seed oil was used for biodiesel production. Sterculia foetida oil was transesterified to lower its FFA using UI and compared with the conventional process. Both heating processes were optimized to yield a maximum of 94.3% at a six molar ratio, 50 °C, (water temp), 1% wt of catalyst (KOH), and 75 min reaction time. Transesterification by UI reduced the total reaction time to 4 min compared to 75 min at the conventional process. Further UI influenced the properties of biodiesel (SOBD) from SO. UI lowered viscosity by 7.3% and density by 5.5% and facilitated using oxygen content of SOBD.

Spatiotemporal variations of industrial carbon emissions (IE) must be scientifically understood, which will be helpful to formulate reasonable emission reduction strategies. Given that spatial distribution of IE is irrelevant to space agents commonly used (such as population and nighttime light), estimation and spatialization methods for total carbon dioxide (CO₂) emissions are not entirely suitable for IE. Therefore, this paper used greenhouse gases observing satellite level 4A product to estimate IE at the city level and used industrial land density to obtain the distribution of IE within the administrative districts. Sectoral emission inventories of 182 cities and a mosaic Asian anthropogenic emission inventory named MIX were used to verify the results. Then, spatiotemporal variation characteristics of China’s IE were analyzed from multiple levels. Results showed that (1) the mean relative error of estimation results was 56.11%, among which 62 cities had relative error of less than 30%. Gridded IE in this paper had high consistency with MIX. (2) Cities with high IE experienced rapid growth from 2009 to 2012, followed by slower growth from 2012 to 2017. (3) Centroid of significant cold and hot spots moved to the southeast and northwest, respectively. Most cities with high annual IE growth had relatively low emission efficiency, mainly located in Inner Mongolia and Xinjiang. Aggregation of medium and high IE grids may represent high emission efficiency. Significant differences still exist between cities in IE, and sustainable development strategies should be formulated according to local conditions. Regions with high annual growth or low emission efficiency are the key to achieving IE reduction targets in future.

This study focuses on the preparation of sodium alginate–coated iron-carbon granules (FeCGs) and their capacity to remove ibuprofen (IBU) by combining Fenton and ultrasound technologies. The preferred preparation conditions are as follows: 2% (w/v) sodium alginate, 10% (w/v) iron fillings and biochar, and used CaCl₂ as the cross-linking agent. 74.72% of IBU was removed by ultrasound/FeCG under 10 g/L FeCG and 250 W ultrasound power. Fenton/FeCG could remove 92.41% of IBU under 10 g/L FeCG and 2 mM H₂O₂. Under the above experimental conditions, ultrasound/FeCG has higher reaction speed (9.44 × 10⁻³ min⁻¹) than Fenton/FeCG (4.95 × 10⁻³ min⁻¹). However, Fenton/FeCG could remove more TOC than ultrasound/FeCG. During the reaction using the Fenton/FeCG system, 11 degradation intermediates were detected, but only 7 intermediates were produced by the ultrasound/FeCG system. A common single-chain product C₅H₁₀O₃ formed by IBU degradation was detected in the reaction products during Fenton/FeCG reaction, which benzene ring structure was destroyed; however, the minimum molecular weight of the product detected using the ultrasound/FeCG system was that of C₈H₁₀O; the benzene ring structure of IBU is not destroyed. This study provides guidance in the preparation of sodium alginate–coated FeCGs, evaluating the applicability of Fenton/FeCG and ultrasound/FeCG, which was meaningful for organic pollution wastewater treatment.

In history, the Yellow River has been suffering from endless floods, which has brought great damage or destruction to agriculture, cities, and people’s lives and property along the river. In this study, the rainfall and runoff characteristics of the Yellow River upstream (Tangnaihai and Lanzhou) after the vegetation restoration were analyzed. With the government implementation of ecological restoration policy since 1999, the vegetation cover in this area has been greatly improved and the normalized difference vegetation index (NDVI) shows a fluctuating increase, with the maximum value of 0.323 (in 2010) and the minimum value of 0.289 (in 2008). The trend of rainfall from 1948 to 2019 was increased, with an average increase of 1.747mm per 10 years. Before the implementation of ecological policy (1948 to 1999), the rainfall decreased by an average of 0.953mm per 10 years, and then increased by an average of 16.519mm per 10 years (2000 to 2019). From 1998 to 2017, the runoff increased by 11.13×10⁸m³ per 10 years (Tangnaihai) and 30.517×10⁸ m³ (Lanzhou) per 10 years, which was due to the increase in rainfall. Annual sediment discharge and annual average sediment concentration decreased by 0.002×10⁸t and 0.103 kg/m³ per 10 years in Tangnaihai, 0.081×10⁸t and 0.395kg/m³ per 10 years in Lanzhou respectively. The decreasing intensity of Lanzhou station was greater. The sediment runoff modulus of Tangnaihai and Lanzhou decreased by 1.4875 km²·year and 4.9439 km²·year respectively. The increase of vegetation has a decreasing effect on sediment discharge. The implementation of ecological restoration policy reduces the amount of sediment into the Yellow River and plays an important role in the protection of ecological environment in the Yellow River Basin.

The speciation, behaviour, and bioavailability of released selenium (Se) from mine effluent discharge to sediments and plants were assessed. Discharged mine effluent containing 65±0.9 μg/L of total Se subsequently contaminated the exposed sediment with an average total Se concentration of 321 mg/kg as well as exposed Typha latifolia plants where 534 and 92 mg/kg were found in roots and leaves, respectively. The strategy of T. latifolia in Se phytoremediation consisted of a phytostabilization and accumulation of Se predominantly in roots. Se plant root uptake was promoted by synergistic effects of Cu, Pb, Zn, and Cd while Co, Fe, Mn, Ni, Na, K, and Mg had antagonistic effects. Se plant uptake was also governed by sediment characteristics mainly pH, total Se, and iron concentration. Se speciation results demonstrated that the most accumulated Se species by T. latifolia roots were selenite and selenomethionine with average concentrations of 2.68 and 2.04 mg/kg respectively while other Se species were the most translocated (average translocation factor of 1.89). Se speciation in roots was positively correlated with sediment pH, organic matter, electrical conductivity, and iron concentration. This study confirms deploying corrective measures for mine effluent treatment before discharge in a sediment-plant environment to protect living organisms from toxic effects. T. latifolia is recommended as a Se-hyperaccumulator to be used for mine soil phytoremediation in cold regions in Canada.

The organophosphate (OP) pesticides are neurotoxic compounds widely used around the world. Evaluation of OP exposure in human studies is important for enabling adequate data analyses and drawing accurate conclusions. The aim of this study was to analyze OP exposure biomarkers and their relationships in a Mexican population with different exposure levels. Dialkylphosphates (DAP) were determined through gas chromatography-mass spectrometry (GC-MSD); acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), arylesterase (AREase), basal paraoxonase 1 (PONase), and β-glucuronidase activities were detected using spectrophotometric methods. The albumin content was determined in a certified clinical laboratory. The DMTP metabolite was found in the highest concentration, and a negative and significant correlation between DAP and cholinesterase activity was observed. Our results suggested that BuChE is a considerably more sensitive biomarker than AChE. In addition, β-glucuronidase was positively correlated with albumin, BuChE, and PONase. In conclusion, our data strongly support the use of two or more biomarkers of exposure in human monitoring and the application of a strong and validated questionnaire.

The current experimental investigation aimed to evaluate performance of a non-cross flow type solar air heater (SAH). The design comprises of an array of continuous longitudinal fins which extends the bottom of absorber surface and alongside to it a jet plate with inline holes has also been encapsulated. The experiments were performed in natural outdoor conditions for a specified range of flow and geometrical parameters, namely, {[Formula: see text], 5700≤ Re ≤ 11700, 0.046 ≤ Dⱼ/Dₕ ≤ 0.076, and X/Dₕ, w/Dₕ = 0.23, 0.46}, respectively. The key indices such as temperature rise parameter (TRP) and collector thermal efficiency are chosen to analyze the performance characteristics of collector. The influence of the above listed parameters on these constraints has been investigated in details. As a function of the entire range of geometrical parameters, an increase in the air flow rate degrades the value of TRP. At the same situation, collector thermal efficiency was found to increase. The peak values of TRP were obtained between 12:00 and 01:00 pm. The rise in air temperature corresponding to hourly deviation of solar intensity has been interpreted at different fin spacing ratios. Furthermore, a parametric optimization approach is employed to identify the optimum values of fin and jet plate parameters yielding maximum collector thermal efficiency. The obtained data have been worked out to plot the design curves for fin and jet parameters. The experimental results were validated with similar literature. The comparative analysis reports a maximum enhancement in TRP of 20.5 % at Dⱼ/Dₕ = 0.076. The percentage improvement in collector thermal efficiency of 16.4% at w/Dₕ = 0.23 and 9.8% at Dⱼ/Dₕ = 0.076 has also been noted with reference to compared works.

Nearly 80% of the population in the Colombo district fulfill their major requirement from the Kelani river. Recent studies are interoperating: most groundwater and surface water in Sri Lanka are contaminated with waterborne pathogens and antibiotics. In the present study, nine antibiotic resistance genes (ARGs) were screened which were belonging to two common groups of antibiotic: penicillin — OPR D, bla TEM, bla OXA, amp a, and amp b — and tetracycline — tet A, tet M, tet B, and tet S. The results of the study reveled that the surface and groundwater of the entire lower part of the Kelani river basin were contaminated with TC and FC (98%). None of the penicillin and tetracycline group antibiotics were detected either surface or groundwater samples except the Kelani river mouth (amoxicillin (AMX) at 0.003 ± 0.001 µg/ml). The results showed that 5 to 15% of surface water samples were positive for penicillin resistance genes (bla TEM, bla OXA, OPR D, amp a, amp b) where ~ 10% of groundwater samples were positive against tetracycline resistance genes (tet A, tet M, tet S, tet B). Among the penicillin resistance genes, the bla TEM (700.576 × 10² copy/ml) was recorded as the highest concentration where the highest tet A gene (439.875 × 10² copy/ml) was detected among the tetracycline resistance genes. Therefore, water quality management and regular monitoring are essential to maintain the quality of drinking water in the meandering part of the Kelani river basin to safeguard river water consumers.