Unintentional injuries pose a great risk for human health in China. Few studies have focused on unintentional injuries at national level from urbanization perspective. The panel data of mortality rate of transportation accidents (TA), fall and drowning and sinking (DS) is investigated, and urbanization development index is collected. Global Moran’s I and linear regression of panel data are applied to determine the spatial distribution and spatial influencing factors of unintentional injuries. The results are the following: (1) The unintentional injury such as TA, fall, and DS shows clear non-uniformity of spatial distribution and relative immobility through time. (2) A 10,000 tons increase in SO₂ emission amount (SO₂ EA) and emission of smoke and dust (ESD) can result in 15.7 and 12.5 increases in TA death in eastern region, respectively. Meanwhile, A 10,000 tons increase in NOₓ emission amount can cause 15.1 increase in TA death in western region. For every 100 billion yuan increase in GDP, the fall death can reduce by 8.4 in central region. One bed increase in number of hospital beds per 10,000 population (NHBP) is favorable for decreasing in fall death by 16.7 in eastern region. However, increase in number of workers enjoying industrial injury (NEWII) does not reduce the fall death in eastern region. (3) For every 1 ten thousand people increase in number of students in ordinary high schools (NSOHS) is conductive to reducing DS death by 7.8 in the western region. Our findings show that there exist spatial differences for urbanization influencing TA, fall, and DS death in eastern, western, and central regions. This study is expected to provide a reference for unintentional injuries control in those three regions.

Toxic metal(loid)s released from tailing residues of mining operations have become a global issue with regard to environmental impacts. Biochar derived from the agriculture waste is considered as a cost-effective and stable material, which could be applied for remediation of sites contaminated with toxic metal(loid)s. In the present study, tailings were amended for 90 days with increasing concentrations of Arundo donax L. stem-derived biochar (ASBC; at 0, 1, 3, and 5%). The 7-day wheat seed germination toxicity test was then used to assess the bioavailability of toxicants in aqueous leachates of the biochar-amended tailing samples. Concentrations of As, Cd, Cu, Pb, and Sb in leachates and the Community Bureau of Reference chemical fractions were determined using ICP-OES. The results indicated that tailing leachates were phytotoxic, an effect that was partially decreased due to increasing concentrations of ASBC, with maximum effects (∼47% of tailing phytotoxicity) occurring at 3% ASBC. Results of further fractionation analyses indicated that increasing concentrations of ASBC amendment decreased the mobile fractions of Cd, Cu, and Pb in tailing samples, but increased the mobilities of As and Sb. A novel approach using the relative toxicity index (= sum of toxicities of individual potentially toxic elements) indicated that the toxicity of the tailings decreased when As was not present, since As decreased the biochar-reduced toxicity. Our results suggest that the ability of using biochar to decrease toxicity in tailings (by sequestration of cationic metals such as Cd, Cu, and Pb) is limited by its inability to immobilize oxyanionic metalloids such as As and Sb.

There is growing interest in recent times for microalgae as a sustainable energy source. However, efficient harvesting of microalgal biomass for various industrial applications is still considered a bottleneck. The present study attempts to evaluate microalgae Scenedesmus sp. harvesting using electro-coagulation–flocculation (ECF). Plackett–Burman design was exploited to explore the significant process parameters, whereas Taguchi’s array design was employed for optimization. The optimal conditions were optimized as initial pH 5.0, electrolysis time 15 min, electrode distance 2 cm, sedimentation time 60 min, and current density 12 mA cm⁻² for complete harvesting. Under optimum conditions, the energy utilization and the operation cost of ECF process was estimated to be 2.65 kWh kg⁻¹ and USD 0.29 kg⁻¹, respectively. Thus, ECF-based microalgae harvesting was found as a low-cost technique. In addition, neutralizing pH and supplementing macro- and micronutrients enabled the flocculated medium to maintain an approximate growth yield in algal cultivation to that of the fresh BG11 medium. ECF did not affect the amount of microalgal lipids (28.6 ± 1.2, % wt.), chlorophyll a (8.3 ± 0.3 μg mL⁻¹), and fatty acid methyl ester composition (C15:0, C16:0, C17:0, and C18:0) as well. These results strongly recommend ECF as the most appropriate and promising method for harvesting Scenedesmus sp. for biofuel production.

Dissolved silicate (DSi) and particulate silica (PSi) concentrations were measured at Arakawa River and at sewage treatment plants (STP) during October 2018 to October 2019. These included flooding observations after super Typhoon Hagibis. At ordinary water levels, the STP effluents were found to be the largest source of DSi in the river. Although DSi concentrations during the flooding events (165 μmol L⁻¹) decreased by about 25% compared to that of ordinary water level (221 μmol L⁻¹), PSi was more than sixteen times higher value (301 μmol L⁻¹) compared to that of ordinary water level (18 μmol L⁻¹). Loading amounts of DSi and PSi (± 1 standard error) were 1.5 × 10⁸ (± 0.1 × 10⁸) and 0.15 × 10⁸ (± 0.02 × 10⁸) mol year⁻¹, respectively, excluding the data of Typhoon Hagibis. Loading amounts during flooding events of DSi and PSi were 1.2 × 10⁸ (± 0.1 × 10⁸) and 2.4 × 10⁸ (± 0.4 × 10⁸) mol 15 days⁻¹, respectively. Although the silica loading at ordinary water level was mainly derived from DSi, the silica loading during flooding events was extremely large due to both high level of DSi and PSi; moreover, it was higher than the annual loading amount.

Ferrous fractions in incinerated bottom ash (IBA) are linked to lower metal dissolution. In the present study, a novel eco-friendly biotechnological approach has been tested for multi-metal leaching using meso-acidophilic Fe²⁺/S° oxidizing bacterial consortium from magnetically separated IBA, owing to the inherent property of IBA to release Fe²⁺. Comprehensive lab-scale studies, first-of-its-kind, considered all the potential elements to understand targeted metal dissolutions from the sample under differential conditions. Concentrations of metals, Al > Ti > Ni > Zn > Cu, as analyzed by ICP-OES, were targeted to be bioleached. XRD analysis indicated the sample to be amorphous with magnetite (Fe₃O₄) and iron (Fe) forming major phases in the magnetic part (IBAM) and titano-magnetite (Fe₃–ₓ. TixO₄) and iron (Fe) for the nonmagnetic part (IBAN). The study indicated that 73.98% Cu, 98.68% Ni, 59.09% Zn, 58.84% Al, and 92.85% Ti could be leached from IBAM when the bioleaching system operates at pH 1.5, 5% pulp density for 8 days. Under similar conditions, within 6 days, 37.55% Cu, 87.99% Ni, 45.03% Zn, 40.72% Al, and 63.97% Ti could be leached from IBAN. Two routes were identified and the mechanism of action has been proposed for the leaching of metals.

In this study, a novel wastewater sampling method based on biofilm collection on a multi-armed polyethylene strips (so called “Octopus”) is proposed. The implementation of this method is a step forward to prevent illegal industrial discharges into sewerage systems and receiving water bodies. Prior applications of biofilm collection were performed in Bielefeld, Germany, in 1994. The success of the method encouraged other municipalities to apply this method for monitoring indirect discharges into sewerage systems. Municipality of Konya, Turkey, started to use the method in 2013. Continuous monitoring has been performed for the determination of regulated heavy metals: chromium (Cr), copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), mercury (Hg) and cadmium (Cd). Unauthorized discharges of Cr, Zn and Ni were identified in Konya by performing sewerage slime tests through biofilm analyses. 2686 mg/kg d.m. Cr, 3949 mg/kg d.m. Zn and 3300 mg/kg d.m. Ni were highest values determined for biofilm samples taken from monitoring sites. In this paper, the principles of the method will be introduced, and findings from the wastewater of Konya City will be given in comparison with findings from Bielefeld, Germany. Conducted results reveal high (and likely illegal) heavy metal discharges into the sewerage system in Konya. The continuous monitoring of sewerage systems with biofilm collectors is an effective and efficient method for point source control of wastewater pollutants.

Proteins of extracellular polymeric substances (EPS) in sewage sludge play a key role in the sludge dewatering. Ethanol can denature proteins and improve sludge dewaterability. In this study, ethanol was used to precondition and combined with Fe³⁺ and rice husk (RH) for dewatering enhancement. The experimental results of the capillary suction time (CST) reduction efficiency indicated that the sewage sludge pretreated with ethanol and Fe³⁺-RH revealed well cooperative formation mechanism with regard to dewatering performance. Using the response surface methodology (RSM) determined that CST reduction efficiency of sewage sludge reached 78.5% under optimal conditions of ethanol 25.21 g/g dry solid (DS), Fe³⁺ 185.70 mg/g DS, and RH 406.02 mg/g DS, respectively. Moreover, the results showed that the composite conditioner is effective for the specific resistance to filtration decreased from initial 1.66E + 13 m/kg to 2.44E + 11 m/kg. The analysis of EPS showed that extractable proteins in EPS increased to maximum when the sludge was pretreated by Fe³⁺-RH because EPS were destroyed and proteins in EPS were released. After the addition of ethanol, extractable protein content was reduced because of protein precipitation and released interstitial water and bound water. The sludge morphology analysis indicated that the RH as a skeleton builder provided the outflow passages, which enhanced the dewatering performance of sludge. From these results, the combination treatment of ethanol and Fe³⁺-RH is a promising synergetic strategy to enhance the dewaterability of sewage sludge.

Silicon (Si) is a beneficial element which was proven to enhance the tolerance of plants to excess metal in a given growth medium. However, the efficacy of Si in mitigating Cu toxicity in plants can vary between plant species and with the amount of copper (Cu) present in the soil/medium. An experiment was performed to investigate the role of Si in alleviating Cu toxicity in Tanzania guinea grass (Panicum maximum cv. Tanzania). The experimental design consisted on complete random blocks with tree replicates containing three Si rates (0, 1, and 3 mmol L⁻¹) and four Cu rates (0.3, 250, 500, and 750 μmol L⁻¹). The grass was grown for 62 days in a greenhouse under hydroponic conditions, with a total of 36 pots. Thirteen days after sowing, seedlings were transplanted to pots and grown for further 25 days, and then exposed to the set Cu rates for 7 days. The plants were also evaluated more for 30 days after the first harvesting. The results confirmed that the Si supply to Tanzania guinea grass can alleviate the effects of excessive Cu. Plant yield increased with Si supply and decreased with the increment of Cu rates in both growth periods. Copper concentration in diagnostic leaves (DL) and in roots, and Cu content in shoots and roots were higher in plants exposed to Cu of 750 μmol L⁻¹ with no Si application than in other combinations. Besides reducing Cu concentration in plant tissues, the most important Si role was reducing the transport of Cu from roots to shoots, which allowed successive harvesting. Graphical abstract

Cladoceran remains (e.g., Daphnia ephippia) in sediments are usually able to accurately reflect the historical succession of cladoceran in lakes. However, mechanisms describing the interaction between density changes of empty ephippia and ephippia containing resting eggs in lake sediments and environmental factors remain unclear. The diversity and vertical changes of Daphnia ephippia in the 30-cm sedimentary layer (equivalent to about 90 years) were investigated in a subtropical Chinese lake, Lake Chaohu. The ephippia of D. similoides sinensis, D. pulex, and D. galeata were identified in the lake sediments. The densities and accumulation rates of both empty ephippia and ephippia containing resting eggs of three Daphnia species showed similar patterns. The values in the surface sedimentary layers (after the 1970s) were notably higher than in the bottom sedimentary layers (before the 1970s). The densities and accumulation rates of both empty ephippia and ephippia containing resting eggs of D. similoides sinensis were higher than those of D. pulex and D. galeata. Highly significant relationships (P < 0.001) between the TN contents and the ephippial densities and accumulation rates of D. similoides sinensis and D. galeata. TP contents had also significant correlations with the ephippial densities and accumulation rates of D. similoides sinensis and D. galeata, whereas it was not significant correlations with those of D. pulex (P > 0.05). Our results suggested that long-term eutrophication and cyanobacterial blooms might significantly affect the production of Daphnia ephippia and their vertical distribution in the sediments in eutrophic lakes.

This study empirically examined the relationship between CO₂ emissions and good governance in oil- and non-oil-producing countries in the SSA region. The findings from this paper revealed very interesting results proving that good governance has a negative relationship with CO₂ emissions. Oil-producing countries have good governance system to help control and reduce CO₂ emissions as compared to non-oil-producing countries. Particularly, in oil-producing countries, business regulatory environment, budget and fiscal management, as well as fiscal policy have a significant negative relationship with CO₂ emissions. But there is rather a positive relationship between these indicators and CO₂ emissions in non-oil-producing countries as they do not have the required structures and arrangements to control CO₂ emissions. Also, in oil-producing countries, property rights and rules have positive relationship with CO₂ emissions but in the case of non-oil-producing countries, there is a negative relationship, meaning that non-oil-producing countries have good legal system and rule-based governance structures that is capable of protecting property rights. There is positive relationship between quality of government administration and CO₂ emissions in oil-producing countries but negative for non-oil-producing countries. Trade liberalization and economic growth have positive relationship with CO₂ emissions in both categories. But urbanization has a negative relationship with CO₂ emissions in non-oil-producing countries but positive for oil-producing. The findings point that effective and efficient institutions is a vital element for SSA countries to help combat the increased emissions of CO₂ to engender growth.