In this study, the concentrations of Zn, Cr, Ni, Cu, Pb, As, Cd, and Hg in the surface sediments of 94 sites sampled from six water systems in the Lake Taihu Basin in China were measured, and the pollution risks and sources of the metals were identified. The results showed that the mean concentrations of Zn, Cr, Ni, Cu, Pb, As, Cd, and Hg in the riverine surface sediments were 163.6, 102.5, 45.5, 44.7, 37.0, 13.3, 0.5, and 0.1 mg/kg, respectively, higher than the corresponding background values (except for Hg). According to the geoaccumulation index (Igₑₒ), the Pb, Ni, Zn, Cu, and Cd concentrations in the riverine surface sediments were generally at low levels of pollution. Based on a pollution load index (PLI) evaluation, the Pb, Ni, Zn, and Cu concentrations in the riverine surface sediments were generally at moderate levels of pollution. According to the thresholds of potential ecological risk, the Cd and Hg concentrations in the riverine surface sediments exhibited moderate potential ecological risks. Multivariate statistical analysis indicated that the Pb in the riverine surface sediments primarily originated from domestic sewage, agricultural wastewater discharge, and petroleum combustion; the concentrations of Cr, Ni, and Zn were influenced by the electroplating and alloy manufacturing industries; the concentrations of Cu and As mainly originated from pesticide use and industrial wastewater discharge; and those of Cd and Hg primarily stemmed from industrial wastewater discharge. This research provides information regarding metallic contamination and the possible associated ecological risks to benthic organisms in the surface sediments of river systems and is useful for developing sustainable strategies for environmental pollution control and management in the Lake Taihu Basin.

The potential of using iron-oxidizing and sulfur-oxidizing bioleaching process for removal of heavy metals (HMs) was investigated at initial unadjusted pH of pig manure (PM). The indigenous iron-oxidizing and sulfur-oxidizing microorganisms enriched from PM were primarily Alicyclobacillus and Acidithiobacillus thiooxidans, respectively. After 12 days of bioleaching, 95% of Cu, 96.5% of Zn, 93.6% of Mn, and 92.7% of Cd were removed from the PM in sulfur-oxidizing bioleaching process. Besides, 92.9% of Cu, 94.1% of Zn, 91.9% of Mn, and 90.5% of Cd were removed in iron-oxidizing bioleaching process. Furthermore, 18.1% of TN, 63.3% of TP, 65.4% of TK, and 45.6% of TOC were leached from the PM in the sulfur-oxidizing bioleaching process, whereas only 21.6% of TN, 32.8% of TP, 4% of TK, and 49% of TOC were solubilized in the iron-oxidizing bioleaching process. The X-ray diffraction analysis results demonstrated that there was a large amount of sulfur remained in bioleached manure from the sulfur-oxidizing process which poses a potential risk of soil re-acidification. The Standards, Measurements and Testing Program extraction protocol study on fraction of P in PM showed that the amount of bioavailable P in the sulfur-oxidizing bioleaching process was dramatically declined, whereas it was elevated by 25.9% in the iron-oxidizing bioleaching process. The results obtained in this study indicated that both the sulfur- and iron-oxidizing bioleaching process were able to efficiently remove HMs from PM at initial unadjusted pH, whereas the iron-oxidizing process was proved better method in reserving the fertilizing property and more friendly to the environment.

Nepal’s efforts to reduce manufacturing-related water pollution have faltered because they rely on traditional methods and regulation. We employed an environmentally extended input–output model to establish direct and indirect relations between water pollution and production in 19 Nepalese manufacturing sectors. We identify which are chief emitters of biochemical oxygen demand and total suspended solids. We categorize three sectors as pollution abatement industries (heavy polluters that portend relatively low clean-up costs) and three as pollution prevention industries (polluters responsible for accelerating pollution by inducing the release of pollutants from other linked sectors). We then draw upon statistical analysis to recommend appropriate pollution-reducing incentives or penalties for both categories. We find that incentives to meet discharge standards are effective for pollution abatement industries and that penalties (e.g., polluter pay) are effective in pollution prevention industries because they underpin Nepal’s economy. If these policies do not succeed as desired, emission control policies are warranted.

Respiratory quotient (RQ) is a parameter proposed as a tool for practical and online monitoring of petroleum hydrocarbon biodegradation. Various environmental factors and remediation conditions affect RQ values. Occasionally, actual RQ values deviate from theoretical RQ values of petroleum hydrocarbon biodegradation. In addition, different RQ calculation and interpretation approaches investigated in literature make it difficult to compare the results. In this study, different RQ calculation and interpretation methods given in the literature were compared and the effects of nitrogen biostimulation with ammonium and nitrate salts on RQ values of petroleum hydrocarbon biodegradation were investigated. Respirometric reactors were used in bioremediation of diesel fuel–contaminated soils. Ammonium sulfate and potassium nitrate were amended to enhance hydrocarbon biodegradation. Total n-alkane levels in the soils were analyzed after the incubation period. RQ values were calculated based on continuous CO₂ and O₂ measurements. Biostimulation with ammonium and nitrate led to significant contaminant biodegradation. The nitrogen source type affected RQ values significantly. It was concluded that in evaluating hydrocarbon biodegradability properties and interpreting biostimulation properties, the use of graphical RQ evaluation methods that include plotted statistical approaches allows access to more useful information than using individual theoretical RQ values.

Fluoride (F) and cadmium (Cd) are two common water pollutants. There is low information about their co-exposure in low doses. So, in this study, we evaluated the combination effects of non-toxic doses of F and Cd and the possible mechanism of their combined interaction. Male rats were exposed to non-toxic doses of sodium fluoride (30 mg/l) and/or cadmium chloride (40 mg/l) in drinking water for 6 weeks. Then, liver tissues were separated and several factors including oxidative stress, mitochondrial toxicity, inflammation, apoptosis, and biochemical and histopathological changes were evaluated. Cd and F alone did not induce any significant changes in evaluated factors compared to control group, while significant elevation in liver enzymes as well as histopathological changes were observed in rats treated with F+Cd. Also, a remarkable increase in oxidative stress markers including reactive oxygen species, lipid peroxidation, and protein carbonyl and also decreasing glutathione and superoxide dismutase levels were detected following co-exposure to F and Cd. Furthermore, a combination of F and Cd resulted in mitochondrial dysfunction, swelling, as well as a reduction in mitochondrial membrane potential in isolated liver mitochondria. On the other hand, TNF-α, IL-1β, and NF-kB inflammatory genes were upregulated in the liver after combined exposure to F and Cd compared to individual treatments. Also, F+Cd treatment increased the Bax expression but decreased the expression of Bcl-2 significantly. These findings suggest that Cd and F can potentiate their individual toxic effects on the liver tissue through disruption of the cellular redox status, inflammation, and apoptosis pathway.

Rivers play an irreplaceable role in nature and human society but are the most vulnerable ecosystem in the world to multiple environmental stressors. However, the global-scale research status and the distribution patterns of major stressors in large rivers remain unclear. This study analysed research publications (12,807 documents from 1900 to 2019) related to six large rivers with continental representativeness to tackle these knowledge gaps. The results showed that the total outputs have grown rapidly over the study period, particularly since the 1990s. Consistent with the varied environmental characteristics and problems among the rivers, the research outputs and focuses demonstrated clear differences, which could further be attributed to geographical location, journal preferences and the economic strength of the country in which the river is located. Overall, climate change was the most frequently and widely considered environmental stressor in large rivers. Regardless of climate change, species diversity and hydropower development were widely addressed in the Amazon, Congo and Mekong river basins. Water pollution was the main stressor studied in the Rhine River and Mississippi River, while agricultural irrigation and drought were the most frequently addressed research subjects in the Murray-Darling River. This study provides a comprehensive understanding of the research status and stressor distribution in large global rivers, highlighting the relationship between river research and geographical regions, pointing out future research directions and providing management guidance for large rivers.

Resource endowment and economic development of different provinces in China vary greatly, resulting in large amount of CO₂ transfers. We need further exploration to help decision makers allocate emission responsibilities reasonably. We construct China’s embodied CO₂ transfer network (CTN) in 2012 from the perspective of provinces and sectors based on multi-regional input-output (MRIO) model and complex network analysis. The key CO₂ transfer nodes and paths, final demand decomposition, topological structure, clustering characteristics, and influencing factors are analyzed. The results show that the average CO₂ transfer length from one province (sector) to another is only 1.323 (1.584). The top three net CO₂ importers (45.39% of the total), located in developed eastern coastal area, mainly import CO₂ from energy-rich but underdeveloped provinces such as Heilongjiang. It presents a CO₂ transfer pattern from north to south and from west to east. CO₂ transfer in energy industry is mainly driven by urban household consumption. Non-adjacent provinces with distance greater than 750 km have no significant spillover effect and difference in technology level has the greatest impact on CTN. This work is important for differentiating the roles of provinces and sectors in CTN, guiding the allocation of carbon credits and controlling total CO₂ emissions.

Air pollution can significantly accelerate the process of material corrosion, which may cause significant economic losses and serious safety incidents. Atmospheric corrosion maps provide atmospheric corrosivity in a given geographic scope, which can guide the designers to select the most suitable anti-corrosion materials for outdoor projects, also provide useful information for maintenance. This article investigated mapping of atmospheric corrosivity in Shandong Province, China. In order to obtain atmospheric corrosivity data, 100 exposure corrosion test sites were established in Shandong according to International Standard Organization (ISO) 8565. Hot-dip galvanized steel samples were exposed for 1 year in the test sites. Taking the results of exposure corrosion test as the data, inverse distance weighting (IDW) and ordinary kriging (OK) interpolation algorithm were used to estimate the atmospheric corrosivity of Shandong Province according to ISO 9223. The validity of OK and IDW was compared in developing atmospheric corrosion maps of Shandong Province on a 1 × 1 km resolution. The cross-validation results showed that OK interpolation algorithm with Gaussian semivariogram model get the best result in the prediction of corrosion rate. When the corrosion category was used as the criterion, the IDW interpolation algorithm of power 4 performed best, predicted results of 74 sites (n = 100) were consistent with observed. However, high mean relative errors (MRE more than 37%) and relatively low correlation (R² about 24%) indicated that the prediction results of the two interpolation algorithms had a large error, which was caused by the low data density and the complicated corrosive factors of the atmosphere.

Over the past 40 years since China’s reform and opening up, the industrial structure has undergone tremendous changes. The rapid development of the economy has been accompanied by a surge in carbon emissions. How to achieve a win-win situation for economic growth and carbon emissions reduction has aroused widespread concern from all sectors of society. Here, this paper discusses the dynamic relationship of industrial structure upgrading, economic growth, and carbon emission reduction. Results show that there is a long-term equilibrium relationship among industrial structure upgrading, economic growth, and carbon emissions. In the short term, when the three variables deviate from the long-term equilibrium state, the non-equilibrium state will be pulled back to equilibrium with the adjustment strength of − 0.0633, − 0.0097, and 0.0013. Carbon emission reduction promotes industrial structure upgrading. Industrial structure upgrading has a greater positive impact on economic growth. Industrial structure upgrading and economic growth have a negative impact on carbon emissions, thereby promoting emission reduction. And at the 10% significance level, there is a one-way Granger causality from carbon emissions to industrial structure upgrading, economic growth can cause one-way changes in carbon emissions, and industrial structure upgrading is a one-way Granger cause of economic growth. Finally, several carbon emission reduction policies are proposed promote industrial restructuring and sustainable economic development.

Fluoride is highly present in the environment, especially in water and its derivatives. Excessive fluoride contribution to diet poses a health risk. Tea leaves accumulate fluoride and the consumption of tea (Camellia sinensis) could pose a risk to human by the excessive fluoride intake. Ninety tea samples were analyzed by potentiometry using a selective fluoride ion electrode. Mixed tea samples (2.82 ± 1.11 mg/L) and black tea samples (2.28 ± 0.79 mg/L) recorded the highest fluoride levels. The contribution of drinking water is important for increasing fluoride levels in teas. The daily consumption of two cups (250 mL per cup) of mixed and black teas prepared with La Laguna tap water does pose a health risk for children (4–8 years old) because of the high contribution percentages (74.4% and 63.6%, respectively) of the Tolerable Upper Intake Level set in 2.5 mg/day by the EFSA (European Food Safety Authority). A minor consumption in children (4–8 years old) and adults during pregnancy is advisable.