Cadmium (Cd) is a heavy metal toxicant as a common pollutant derived from many agricultural and industrial sources. The absorption of Cd takes place primarily through Cd-contaminated food and water and, to a significant extent, via inhalation of Cd-contaminated air and cigarette smoking. Epidemiological data suggest that occupational or environmental exposure to Cd increases the health risk for osteoporosis and spontaneous fracture such as itai-itai disease. However, the direct effects and underlying mechanism(s) of Cd exposure on bone damage are largely unknown. We used primary bone marrow-derived mesenchymal stromal cells (BMMSCs) and found that Cd significantly induced BMMSC cellular senescence through over-activation of NF-κB signaling pathway. Increased cell senescence was determined by production of senescence-associated secretory phenotype (SASP), cell cycle arrest and upregulation of p21/p53/p16ᴵᴺᴷ⁴ᵃ protein expression. Additionally, Cd impaired osteogenic differentiation and increased adipogenesis of BMMSCs, and significantly induced cellular senescence-associated defects such as mitochondrial dysfunction and DNA damage. Sprague-Dawley (SD) rats were chronically exposed to Cd to verify that Cd significantly increased adipocyte number, and decreased mineralization tissues of bone marrow in vivo. Interestingly, we observed that Cd exposure remarkably retarded bone repair and regeneration after operation of skull defect. Notably, pretreatment of melatonin is able to partially prevent Cd-induced some senescence-associated defects of BMMSCs including mitochondrial dysfunction and DNA damage. Although Cd activated mammalian target of rapamycin (mTOR) pathway, rapamycin only partially ameliorated Cd-induced cell apoptosis rather than cellular senescence phenotypes of BMMSCs. In addition, a selective NF-κB inhibitor moderately alleviated Cd-caused the senescence-related defects of the BMMSCs. The study shed light on the action and mechanism of Cd on osteoporosis and bone ageing, and may provide a novel option to ameliorate the harmful effects of Cd exposure.

Despite the wide applications of end member mixing analysis (EMMA) for assigning the sources of dissolved organic matter (DOM) in aquatic environment, there was no study attempting to test the applicability of EMMA for predicting environmental reactivity of DOM. This study aimed to explore the feasibility of EMMA, or the concept of ideal mixing behavior of end members, for describing several well-known DOM reactivities using two DOM end member sources (i.e., soil and algae) at varying mixing ratios. The selected DOM reactivities were trihalomethane formation potential (THMFP), mineral adsorption amount, pyrene binding, membrane resistance, and biodegradation potential. Among the tested DOM functions, all were found to follow the ideal mixing behavior, presenting the linear relationships between the source mixing ratios and the tested reactivity with the R² value of >0.80. The ideal mixing behavior of the DOM functions was more pronounced than that based on several spectroscopic indicators derived from UV absorption and fluorescence spectroscopy. This study provided insight into potential applicability and limitation of EMMA approach in monitoring and predicting environmental functions of DOM in aquatic systems where identified DOM sources are mixed and vary dynamically with the mixing ratios.

Environmental water quality guidelines often work under the assumption that the toxicity of environmental pollutants is identical when present in isolation or in a complex chemical mixture. Thus, there is a crucial gap in our knowledge regarding how these toxicants interact and alter the toxicological effects in aquatic organisms. The present study examined the effects of acute (72-hr) aqueous exposures of Cadmium (Cd), a highly toxic non-essential trace metal, and Benzo[a]Pyrene (B[a]P), a prototypical polycyclic aromatic hydrocarbon (PAH) in adult zebrafish. Following a range-finding series of individual single-toxicant exposures, a second series was carried out using select concentrations in binary mixture exposures (using 5.8 or 22 μg/L for Cd; 0.44 or 1.07 μg/L for B[a]P). Our results demonstrated that tissue accumulation of both toxicants increased significantly in the presence of the second toxicant relative to single-toxicant exposures. Cd-only and B[a]P-only single toxicant exposures caused a significant downregulation of cytochrome p4501a (CYP1A1) and metallothionein-2 (MT2) mRNA in the gills, respectively, however binary co-exposures using both toxicants resulted in strong up-regulation of CYP1A1 and MT2. Additionally, co-exposures caused a strong induction of SOD1 and CAT mRNA transcript levels in the gill. The observed increase in body burden and transcript modulation did not translate into additive or more-than-additive toxic effects (oxidative stress) in zebrafish.

Extracellular Polymeric Substances (EPS) influenced Poly Cyclic Aromatic Hydrocarbons (PAHs) degrading Klebsiella pneumoniae was isolated from the marine environment. To increase the EPS production by Klebsiella pneumoniae, several physicochemical parameters were tweaked such as different carbon sources (arabinose, glucose, glycerol, lactose, lactic acid, mannitol, sodium acetate, starch, and sucrose at 20 g/L), nitrogen sources (ammonium chloride, ammonium sulphate, glycine, potassium nitrate, protease peptone and urea at 2 g/L), different pH, carbon/nitrogen ratio, temperature, and salt concentration were examined. Maximum EPS growth and biodegradation of Anthracene (74.31%), Acenaphthene (67.28%), Fluorene (62.48%), Naphthalene (57.84%), and mixed PAHs (55.85%) were obtained using optimized conditions such as glucose (10 g/L) as carbon source, potassium nitrate (2 g/L) as the nitrogen source at pH 8, growth temperature of 37 °C, 3% NaCl concentration and 72 h incubation period. The Klebsiella pneumoniae biofilm architecture was studied by confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM). The present study demonstrates the EPS influenced PAHs degradation of Klebsiella pneumoniae.

In this study, we investigated the daily variability of PM₁₀ concentrations in January in Korea during the past 19 years (2001–2019), as well as the associated atmospheric circulation patterns. The daily PM₁₀ concentrations were classified into three cases: low (L; < 50 μg/m³), high (H; 50–100 μg/m³), and extremely high (EH; ≥ 100 μg/m³). We found that the strength of the East Asian winter monsoon influenced the PM₁₀ variability in the L and H cases. However, the EH cases were strongly influenced by the rapid growth of barotropic warming (anticyclonic anomaly) over the eastern North Atlantic and Northern Europe (ENE), and the stationary Rossby waves grew rapidly over Eurasia within only four days. Analysis of the quasi-geostrophic geopotential tendency budget revealed that the anticyclonic anomaly over the ENE was enhanced by vorticity advection. Linear baroclinic model experiments confirmed that vorticity forcing over the ENE induces favorable atmospheric conditions for the occurrence of EH PM₁₀ events in East Asia. As a result, the PM₁₀ concentration sharply increased sharply by approximately three times over four days. This study suggests that understanding atmospheric teleconnections between the ENE and East Asia can effectively predict the occurrence of EH PM₁₀ events in Korea, helping to reduce the human health risks from atmospheric pollution.

Arsenic (As) is a toxic pollutant that mainly enters the human body via plants. Therefore, understanding the strategy for reducing arsenic accumulation in plants is important to human health and the environment. Aquaporins are ubiquitous water channel proteins that bidirectionally transport water across cell membranes and play a role in the transportation of other molecules, such as glycerol, ammonia, boric acid, and arsenic acid. Previously, we observed that Arabidopsis PIP2;2, encoding a plasma membrane intrinsic protein, is highly expressed in NtCyc07-expressing Arabidopsis, which shows a higher tolerance to arsenite (As(III)). In this study, we report that the overexpression of AtPIP2;2 enhanced As(III) tolerance and reduced As(III) levels in yeast. Likewise, AtPIP2;2-overexpressing Arabidopsis exhibited improved As(III) tolerance and lower accumulation of As(III). In contrast, atpip2;2 knockout Arabidopsis showed reduced As(III) tolerance but no significant change in As(III) levels. Interestingly, the AtPIP2;2 transcript and protein levels were increased in roots and shoots of Arabidopsis in response to As(III). Furthermore, As(III) efflux was enhanced and As(III) influx/accumulation was reduced in AtPIP2;2-expressing plants. The expression of AtPIP2;2 rescued the As(III)-sensitive phenotype of acr3 mutant yeast by reducing As levels and slightly reduced the As(III)-tolerant phenotype of fps1 mutant yeast by enhancing As content, suggesting that AtPIP2; 2 functions as a bidirectional channel of As(III), while the As(III) exporter activity is higher than the As(III) importer activity. All these results indicate that AtPIP2;2 expression promotes As(III) tolerance by decreasing As(III) accumulation through enhancing As(III) efflux in Arabidopsis. This finding can be applied to the generation of low arsenic crops for human health.

This study develops an oil spill environmental vulnerability model for predicting and mapping the oil slick trajectory pattern in Kota Tinggi, Malaysia. The impact of seasonal variations on the vulnerability of the coastal resources to oil spill was modelled by estimating the quantity of coastal resources affected across three climatic seasons (northeast monsoon, southwest monsoon and pre-monsoon). Twelve 100 m³ (10,000 splots) medium oil spill scenarios were simulated using General National Oceanic and Atmospheric Administration Operational Oil Modeling Environment (GNOME) model. The output was integrated with coastal resources, comprising biological, socio-economic and physical shoreline features. Results revealed that the speed of an oil slick (40.8 m per minute) is higher during the pre-monsoon period in a southwestern direction and lower during the northeast monsoon (36.9 m per minute). Evaporation, floating and spreading are the major weathering processes identified in this study, with approximately 70% of the slick reaching the shoreline or remaining in the water column during the first 24 h (h) of the spill. Oil spill impacts were most severe during the southwest monsoon, and physical shoreline resources are the most vulnerable to oil spill in the study area. The study concluded that variation in climatic seasons significantly influence the vulnerability of coastal resources to marine oil spill.

Common plasticizers and their alternatives are environmentally ubiquitous and have become a global problem. In this study, common plasticizers (phthalates and metabolites) and new alternatives [bisphenol analogs, t-butylphenyl diphenyl phosphate (BPDP), and bisphenol A bis(diphenyl phosphate) (BDP)] were quantified in urine and hair samples from children in Hong Kong, drinking water (tap water/bottled water) samples, and airborne particle samples from 17 kindergartens in Hong Kong. The results suggested that locally, children were exposed to various plasticizers and their alternatives. High concentrations of BPDP and BDP were present in urine, hair, tap water, bottled water, and air particulate samples. The geometric mean (GM) concentrations of phthalate metabolites in urine samples (126–2140 ng/L, detection frequencies < 81%) were lower than those detected in Japanese and German children in previous studies. However, a comparison of the estimated daily intake values for phthalates in tap water [median: 10.7–115 ng/kg body weight bw/day] and air particles (median: 1.23–7.39 ng/kg bw/day) with the corresponding reference doses indicated no risk. Bisphenol analogs were detected in 15–64% of urine samples at GM concentrations of 5.26–98.1 ng/L, in 7–74% of hair samples at GM concentrations of 57.5–2390 pg/g, in 59–100% of kindergarten air samples at GM concentrations of 43.1–222 pg/m³, and in 33–100% of tap water samples at GM concentrations of 0.90–3.70 ng/L. A significant correlation was detected between the concentrations of bisphenol F in hair and urine samples (r = 0.489, p < .05). The estimated daily urinary excretion values of bisphenol analogs suggest that exposure among children via tap water intake and airborne particle inhalation in kindergartens cannot be ignored in Hong Kong.

The study aimed to evaluate the ecotoxicity of soil (S) amended with biochars (BCKN) produced by the thermal conversion of sewage sludge (SSL) at temperatures of 500 °C, 600 °C, or 700 °C and SSL itself. The ecotoxicological tests were carried out on organisms representing various trophic levels (Lepidium sativum in plant, Folsomia candida in invertebrates, and Aliivibrio fischeri in bacteria). Moreover, the study evaluated the effects of three plants (Lolium perenne, Trifolium repens, and Arabidopsis thaliana) growing on BCKN700-amended soil on its ecotoxicological properties. The experiment was carried out for six months. In most tests, the conversion of sewage sludge into biochar caused a significant decrease in toxicity by adding it to the soil. The pyrolysis temperature directly determined this effect. The soil amended with the biochars produced at higher temperatures (600 °C and 700 °C) generally exhibited lower toxicity to the test organisms than the SSL. Because of aging, all the biochars lost their inhibition properties against the tested organisms in the solid-phase tests and had a stimulating influence on the reproductive ability of F. candida. With time, the fertilizing effect of the BCKN700 amended soil also increased. The aged biochars also did not have an inhibitory effect on A. fischeri luminescence in the leachate tests. The study has also demonstrated that the cultivation of an appropriate plant species may additionally reduce the toxicity of soil fertilized with biochar. The obtained results show that the conversion of sewage sludge to biochar carried out at an appropriate temperature can become a useful method in reducing the toxicity of the waste and while being safe for agricultural purposes.

Tetrachlorobenzoquinone (TCBQ) is a common metabolite of persistent organic pollutants pentachlorophenol (PCP) and hexachlorobenzene (HCB). Current reports on the toxicity of TCBQmainly focused on its reproductive toxicity, neurotoxicity, carcinogenicity and cardiovascular toxicity. However, the possible immunotoxicity of TCBQ remains unclear. The release of neutrophil extracellular traps (NETs) is a recently discovered immune response mechanism, however, excess NETs play a pathogenic role in various immune diseases. In an attempt to address concerns regarding the immunotoxicity of TCBQ, we adopted primary mouse neutrophils as the research object, explored the influence of TCBQ on the formation of NETs. The results showed that TCBQ could induce NETs rapidly in a reactive oxygen species (ROS)-dependent manner. Moreover, TCBQ promoted the phosphorylation of c-Jun N-terminal kinase (JNK) mitogen activated protein kinase (MAPK), but not p38 or extracellular signal related kinase (ERK) in neutrophils. Mechanistically, JNK activation enhanced the expression of NADPH oxidase enzyme 2 (NOX2), which further accelerated the generation of ROS and thus amplified the formation of NETs. The pharmacologic blockage of JNK or NOX2 effectively ameliorated TCBQ-induced ROS and NETs, implying that ROS-JNK-NOX2 positive feedback loop was involved in TCBQ-induced NETs. In conclusion, we speculated that targeting NETs formation would be a promising therapeutic strategy in modulating the immunotoxicity of TCBQ.