Biomass burning tracers have been widely used to identify biomass burning types, but such tools can sometimes cause large uncertainties in the source attribution studies of PM₂.₅ (particles with an aerodynamic diameter of smaller than 2.5 μm). To quantify the relative importance of the major biomass burning tracers in PM₂.₅ released from biofuels combusted in the North China Plain, combustion experiments under the smoldering and flaming combustion conditions were conducted using nine types of typical household biofuels including two types of agricultural wastes, five types of hardwoods, one softwood, and one mixed wood briquette. PM₂.₅ samples were collected from the combustion experiments and source profiles of PM₂.₅ were thus determined for various biofuels under the two different combustion conditions. Carbonaceous species including organic carbon (OC) and elemental carbon (EC) were the major chemical components of the PM₂.₅ released from combustion of all the tested biofuels, with mass fractions of 37–45% and 4–7% under the smoldering condition and 11–25% and 7–29% under the flaming condition, respectively. Higher mass fractions of water-soluble inorganic ions (WSIIs, e.g., K⁺ and Cl⁻) in PM₂.₅ were observed under the flaming than smoldering combustion condition, while anhydrosugars (levoglucosan (LG) and mannosan (MN)) presented in an opposite pattern. The average LG/MN ratio in PM₂.₅ changed significantly with biofuel type (20–55 for agricultural wastes, 10–22 for hardwoods (except elm) and 3–6 for softwood), but varied little with combustion condition. In contrast, the K⁺/LG ratio in PM₂.₅ varied significantly between smoldering (<0.2) and flaming (>0.6) combustion conditions for all the biofuel types except softwood. Results from this study suggested that the ratio LG/MN was the best tracer for identifying the biofuel types and the ratio K⁺/LG is suitable for identifying the combustion conditions in this region.

Degradation of freshwater ecosystems by uncontrolled human activities is a growing concern in the tropics. In this regard, we aimed at testing an integrative framework based on the IFEQ index to assess freshwater ecosystem health of river basins impacted by intense livestock and agricultural activities, using the Muchacho River Basin (MRB) as a case study. The IFEQ combine multiple lines of evidence such as riverine hydromorphological analysis (LOE 1), physicochemical characterization using ions and pesticides (LOE 2), aquatic macroinvertebrate monitoring (LOE 3), and phytotoxicological essays with L. sativa (LOE 4). Overall, results showed an important reduction in streamflow and an elevated increase in ion concentrations along the MRB caused by deforestation and erosion linked to agricultural and livestock activities. Impacts of the high ion concentrations were evidenced in macroinvertebrate communities as pollution-tolerant families, associated with high conductivity levels, represented 92 % of the total abundance. Pollution produced by organophosphate pesticides (OPPs) was critical in the whole MRB, showing levels that exceeded 270-fold maximum threshold for malathion and 30-fold for parathion, the latter banned in Ecuador. OPPs concentrations were related to low germination percentages of Lactuca sativa in sediment phytotoxicity tests. The IEFQ index ranged from 44.4 to 25.6, indicating that freshwater ecosystem conditions were “bad” at the headwaters of the MRB and “critical” along the lowest reaches. Our results show strong evidence that intense agricultural and livestock activities generated significant impacts on the aquatic ecosystem of the MRB. This integrative approach better explains the cumulative effects of human impacts, and should be replicated in other basins with similar conditions to help decision-makers and concerned inhabitants generate adequate policies and strategies to mitigate the degradation of freshwater ecosystems.

Microbial-mediated Sb volatilization is a poorly understood part of the Sb biogeochemical cycle. This is mostly due to a lack of laboratory and field-deployable methods that are capable of quantifying low-level emissions of Sb from diffuse sources. In this study, we validated two methods using a H₂O₂ -HNO₃ liquid chemotrap and an activated coconut shell charcoal solid-phase trap, achieving an absolute limit of detection of 4.6 ng and below 2.0 ng Sb, respectively. The activated charcoal solid-phase trapping method, the most easily operated method, was then applied to contaminated shooting range soils. Four treatments were tested: 1) flooded, 2) manure amended + flooded, 3) 70 % water holding capacity, and 4) manure amendment +70 % water holding capacity, since agricultural practices and flooding events may contribute to Sb volatilization. Volatile Sb was only produced from flooded microcosms and manure amendment greatly influenced the onset and amount of volatile Sb produced. The highest amount of volatile Sb produced, up to 62.1 ng kg⁻¹ d⁻¹, was from the flooded manure amended soil. This suggests that anaerobic microorganisms may potentially be drivers of Sb volatilization. Our results show that polluted shooting range soils are a source of volatile Sb under flooded conditions, which may lead to an increase in the mobility of Sb. Some of these volatile Sb species are toxic and genotoxic, highlighting the role of Sb volatilization on environmental health, especially for individuals living in contaminated areas exposed to wetlands or flooded conditions (e.g., rice paddy agriculture surrounding mining areas). This work paves way for research on Sb volatilization in the environment.

This study investigates the occurrence and distribution of microplastics in water, sediment, and crayfish samples within pond and rice-crayfish co-culture breeding modes in Jianli prefecture, China. Microplastics in environmental and biological samples were systematically extracted by CaCl₂ solution, digested by H₂O₂ and KOH, and identified by μ-FTIR. A cleansing treatment for crayfish was performed in pure water before dissection and microplastic accumulation in different tissues (gill, stomach, gut, and flesh) of non-cleansed and cleansed crayfish were compared. The average microplastic abundances were 1.3 ± 0.1–2.5 ± 0.1 particles/L, 0.03 ± 0.01–0.04 ± 0.02 particles/g, and 0.17 ± 0.07–0.92 ± 0.19 particles/individual in water, sediment, and crayfish samples, respectively. Microplastics were detected in all studied crayfish tissues, except the flesh. There were no significant differences in microplastic abundances in water (P = 0.82), sediment (P = 0.90), and crayfish (P = 0.47 for non-cleansed samples; P = 0.30 for cleansed samples) between two breeding modes despite the detection of relatively higher microplastic abundances in the samples from the pond breeding mode. Microplastic accumulation in non-cleansed crayfish stomachs and guts (0.71 ± 0.18 particles/individual) was higher (P < 0.01) than that recorded in their gills (0.13 ± 0.06 particles/individual). Moreover, microplastics present in the stomachs and guts of cleansed crayfish were significantly less abundant (P < 0.01) than in non-cleansed crayfish, although this was not observed in the gills (P = 0.99). The majority of microplastic particles in this study had fiber-like shapes, blue and transparent colors, a size smaller than 1 mm, and polymer types of PP:PE and PE. The results demonstrate that microplastics in the environment can accumulate in the internal tissues of crayfish, which may pose a potential risk to humans through food consumption without the removal of the gills, stomach, and guts. This study provides valuable information for understanding microplastic accumulation in the different tissues of crayfish and the potential risk of human exposure to microplastics from crayfish as a food supplement.

In the present work, we propose a novel algorithm to determine the scattering coefficient of OA by evaluating the relationships of the MSEs for primary organic aerosol (POA) and secondary organic aerosol (SOA) with their mass concentrations at three distinct sites, i.e. an urban site, a rural site, and a background site in China. Our results showed that the MSEs for POA and SOA increased rapidly as a function of mass concentration in low mass loading. While the increasing rate declined after a threshold of mass loading of 50 μg/m³ for POA, and 15 μg/m³ for SOA, respectively. The dry scattering coefficients of submicron particles (PM₁) were reconstructed based on the algorithm for POA and SOA scattering coefficient and further verified by using multi-site data. The calculated dry scattering coefficients using our reconstructing algorithm have good consistency with the measured ones, with the high correlation and small deviation in Shanghai (R² = 0.98; deviations: 2.9%) and Dezhou (R² = 0.90; deviations: 4.7%), indicating that our algorithms for OA and PM₁ are applicable to predict the scattering coefficient of OA and Submicron particle (PM₁) in China.

Total concentration and chemical partitioning of heavy metals are commonly used in environmental quality assessment; however, their comparability and comprehensive application are far less discussed. Herein, bioavailability, pollution and eco-risk of As, Cd, Cr, Cu, Ni, Pb and Zn in surface sediments of Erhai Lake were evaluated referring to multiple indices following the experimental methods of complete digestion, optimized Community Bureau of Reference (BCR) and 1.0 M HCl extractions. Results of bioavailability for most metals were similar and comparable from BCR and HCl extractions. While bioavailable concentrations of Cd and Pb from HCl extraction were significantly (p < 0.01) lower than those from BCR extraction, indicating BCR extraction is more efficient. Results of enrichment factor (EF) and concentration enrichment ratio (CER) suggested that Cd was the highest polluted element followed by As, Pb and Zn, whereas Cr, Cu and Ni were mainly natural in origin. Similar concentrations of anthropogenic As from EF and CER assessments indicated anthropogenic As mainly existed in bioavailable form. However, anthropogenic Cd, Pb and Zn existed in both bioavailable and residue forms, resulting in the underestimation of anthropogenic metals by the CER assessment. The sediment quality guidelines (SQGs), potential ecological risk index (Er) and risk assessment code (RAC) showed inconsistent eco-risks for each of the metals except Cd. Combining pollution level and chemical partitioning with SQGs, Er and RAC assessments, high eco-risk of Cd, moderate eco-risk of As and Pb, and low eco-risk of Cr, Cu, Ni and Zn were graded. Our study highlights the limitation of single index and the necessity of integrating multiple indices following total concentration and chemical partitioning in metal pollution and eco-risk assessments.

In the past decades, research on water pollution microplastics (MPs) has intensified tremendously. However, the relationship between MPs and environmental factors in urban river networks is under researched. Our study selected 65 sampling sites from a sophisticated urban river network system in Shanghai Municipality, China. Here, the combined influence of land-use types, river width, and water quality parameters to explore MPs distribution patterns. We found that MPs abundance ranged from 0.7 to 24.3 items/L, and the spatial difference in abundance was significant at a limited number of sampling sites. Fibrous MPs were the most abundant MPs in the river system. 72.7% of MPs <3 mm. Of the ten polymers detected, polypropylene and polyethylene terephthalate were predominant. In addition, cotton fiber was the main non-plastic component found in the samples. Moreover, land-use types showed no significant impact on MPs in the buffer zone of the sampling sites. However, point source pollution may cause an abnormal increase in MPs abundance. Through redundant analysis, we found that the phytoplankton abundance (e.g., chlorophyll-a) was influenced by MPs shape, while the river width influence MPs size. Construction activities were identified as the leading point source of pollution for the abnormal increase in local MPs pollution. Our results will inform on MPs distribution patterns in the super-metropolis river system.

In this study, the influencing factors and sources of historical changes in polycyclic aromatic hydrocarbons (PAHs) in the sediment core of Fuxian Lake were analyzed. Before 1970, the Σ₁₆PAH concentration fluctuated widely, with one or more maximum values. During 1971–2004, the Σ₁₆PAH concentration showed a slow growth trend, while during 2005–2017, the concentration increased sharply, reaching a peak value of 821 ng g⁻¹. dw in 2017. The results of a positive matrix factorization (PMF) model demonstrated that before 1970, PAHs were mainly derived from biomass burning in the Fuxian Lake sediment core, with an overall contribution of 40 %. During 1971–2004, the source of PAHs was mainly coal combustion, with an overall contribution of 34 %. During 2005–2017, PAHs primarily originated from traffic, with an overall contribution of 33 %. Population, coal, GDP, motor, and petroleum had a significant influence on low molecular weight (LMW) PAHs in 1980–2004 and 2005–2017. Motor, coal, population, and GDP had a greater impact on high molecular weight (HMW) PAHs. Before 1970 and in 1971–2004, meteorological factors had little effect on PAHs in the sediment core in Fuxian Lake. During 2005–2017, day and rainfall were significantly negatively correlated with HMW PAHs, while temperature and wind were not correlated with PAH concentrations. During 2005–2017, total organic carbon (TOC) and total nitrogen (TN) had greater adsorption effects on HMW PAHs than on LMW PAHs. Before 1970 and in 1971–2004, the adsorption effects of TOC and TN on 3–4-ring PAHs were greater than those of 2-ring and 5–6-ring PAHs. Total phosphorus (TP) had no adsorption effect on PAHs in the entire sedimentary column.

The hazardous effects of herbicides are well known; however, their effects on the reproductive system remain unclear. In this study, we demonstrated the anti-proliferative effects of dinitramine (DN) on immature murine testicular cell lines (Leydig and Sertoli cells) mediated via endoplasmic reticulum (ER) stress-induced calcium dysregulation in the cytosol and mitochondria. The results demonstrated that the viability and proliferation of DN-treated TM3 and TM4 cells decreased significantly, even in the spheroid state. DN induced the apoptosis of TM3 and TM4 cells and decreased the expression of genes related to cell cycle progression. Treatment with DN increased the cytosolic and intramitochondrial levels of calcium by activating ER stress signals. DN activated the Erk/P38/Jnk Mapk pathway and inactivated the Pi3k/Akt pathway in murine testicular cells. Co-treatment with 2-aminoethoxydiphenyl borate (2-APB) mitigated DN-induced calcium upregulation in both testicular cell lines. Although 2-APB did not antagonize the anti-proliferative effect of DN in TM3 cells, treatment with 2-APB and 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid restored the proliferation of DN-treated TM4 cells.

The remarkable journey of progression of mankind has created various impacts in the form of polluted environment, amassed heavy metals and depleting resources. This alarming situation demands sustainable energy resources and approaches to deal with these environmental hazards and power deficit. Pyrolysis and co-pyrolysis address both energy and environmental issues caused by civilization and industrialization. The processes use hazardous waste materials including waste tires, plastic and medical waste, and biomass waste such as livestock waste and agricultural waste as feedstock to produce gas, char and pyrolysis oil for energy production. Usage of hazardous materials as pyrolysis and co-pyrolysis feedstock reduces disposal of harmful substances into environment, reducing occurrence of soil and water pollution, and substituting the non-renewable feedstock, fossil fuels. As compared to combustion, pyrolysis and co-pyrolysis have less emission of air pollutants and act as alternative options to landfill disposal and incineration for hazardous materials and biomass waste. Hence, stabilizing heavy metals and solving the energy and waste management problems. This review discusses the pyrolysis and co-pyrolysis of biomass and harmful wastes to strive towards circular economy and eco-friendly, cleaner energy with minimum waste disposal, reducing negative impact on the planet and creating future possibilities.