Gramshelton7821

The toxic metal(loid)s TMs resistant bacterium Brevundimonas diminuta was isolated for the first time from mines polluted soil in Fengxian, China, and assessed for its potential for Cd and Zn precipitation in Cd and Zn co-contaminated aqueous solution at various Cd and Zn levels (20, 40, 80, 160, and 200 mg L-1), pH values (5, 6, 7, 8, and 9), and temperatures (20, 25, 30, and 35 °C). B. diminuta showed a high resistance to both Cd and Zn and was able to precipitate up to 99.2 and 99.7% of dissolved Cd and Zn respectively, at a pH of 7 and temperature of 30 °C. B. diminuta reduced the dissolved concentrations of Cd and Zn below the threshold levels in water. The 3D-EEM analysis revealed the presence of extracellular polymeric substances (EPS) such as tryptophan indicating bacterial growth under Cd/Zn stress. FTIR showed polysaccharides, CO32-, CaCO3, PO43-, and proteins, which may enhance bacterial growth and metal precipitation. SEM-EDS confirmed the leaf-like and granular shape of the biological precipitation and reduction in the percent weight of TMs, which promoted the adhesion/adsorption of Cd2+, Zn2+, and Ca2+. Moreover, XRD analysis confirmed the precipitation of Cd, Zn, and Ca in the form of CdCO3/Cd3(PO4)2, ZnCO3/ZnHPO4/Zn2(OH)PO4/Zn3(PO4)2, and CaCO3/Ca5(PO3)4OH, respectively. These findings indicate that Brevundimonas diminuta can be used for the bioremediation of TMs-contaminated aquatic environments.Microplastic, a well-documented emerging contaminant, is widespread in aquatic environments resulting from the production and fragmentation of large plastics items. The knowledge about the chronic toxic effects and behavioral toxicity of microplastics, particularly on freshwater benthic macroinvertebrates, is limited. In this study, adult Asian clams (Corbicula fluminea) were exposed to gradient microplastic solutions for 42 days to evaluate behavioral toxicity and chronic biotoxicity. The results showed that microplastics caused behavior toxicity, oxidative stress, and tissue damage in high-concentration treatments. Siphoning, breathing, and excretion was significantly inhibited (p less then 0.05) at high-concentration treatments, suggesting that high-concentration microplastics induced behavioral toxicity in C. fluminea. Malondialdehyde content, superoxide dismutase, catalase, and glutathione reductase activities were significantly enhanced (p less then 0.05) and the acetylcholinesterase was significantly inhibited (p less then 0.05) throughout the exposure period in high-concentration treatments. Enzymes associated with energy supply were significantly higher at high-concentration microplastics treatments on D7 and D21. However, they recovered to a normal level on D42. The instability of the enzymes indicated that high-concentration microplastics induced oxidative stress and disorder in neurotransmission and energy supply. The gills of C. fluminea in treatments underwent cilia degeneration, which indicated that microplastics caused tissue damage in the gills. The analysis of integrated biomarker response values revealed that high-concentration microplastics led to long-term effects on the health of C. fluminea. In conclusion, continuous exposure to microplastics (10 mg L-1) would damage physical behavior and the antioxidant system of C. fluminea.Understanding the cumulative risk of chemical mixtures at environmentally realistic concentrations is a key challenge in honey bee ecotoxicology. Ecotoxicogenomics, including transcriptomics, measures responses in individual organisms at the molecular level which can provide insights into the mechanisms underlying phenotypic responses induced by one or more stressors and link impacts on individuals to populations. Here, fifth instar honey bee larvae were sampled from a previously reported field experiment exploring the phenotypic impacts of environmentally realistic chronic exposures of the pesticide imidacloprid (5 μg.kg-1 for six weeks) and the acaricide thymol (250 g.kg-1 applied via Apiguard gel in-hive for four weeks), both separately and in combination. RNA-seq was used to discover individual and interactive chemical effects on larval gene expression and to uncover molecular mechanisms linked to reported adult and colony phenotypes. Pirinixic The separate and combined treatments had distinct gene expression profiles which represented differentially affected signaling and metabolic pathways. The molecular signature of the mixture was characterised by additive interactions in canonical stress responses associated with oxidative stress and detoxification, and non-additive interactions in secondary responses including developmental, neurological, and immune pathways. Novel emergent impacts on eye development genes correlated with long-term defects in visual learning performance as adults. This is consistent with these chemicals working through independent modes of action that combine to impact common downstream pathways, and highlights the importance of establishing mechanistic links between molecular and phenotypic responses when predicting effects of chemical mixtures on ecologically relevant population outcomes.The commercially sold cigarettes contain more than 7000 chemicals, and their combustion produces potential toxicants in mainstream smoke (MS), sidestream smoke (SS), secondhand smoke (SHS), thirdhand smoke (THS), and discarded cigarette butts (CBs). We conducted a systematic review of published literature to compare the toxicants produced in each of these phases of tobacco combustion (MS, SS, and CBs). The initial search included 12,301 articles, but after screening and final restrictions considering the aims of this review, 159 published studies were selected for inclusion. Additionally, SHS and THS are briefly discussed here. Overall, polycyclic aromatic hydrocarbons (PAHs) and other aromatic hydrocarbons have been represented in more studies than other compounds. However, metals and nitrosamines were detected in higher concentrations than other components in SS. The concentrations of most PAHs and other aromatic hydrocarbons in MS and SS are higher compared to concentrations found in CBs. Also, the concentrations of all the studied carbonyl compounds, aldehydes and ketones in SS and MS were higher than in CBs. The mean levels of alcohols and phenols in SS were higher than those reported for both MS and CBs. Tobacco toxicants are inhaled by smokers and transmitted to the environment through SS, SHS, THS, and discarded CBs. However, further studies are necessary to assess adverse effects of toxicants found in CBs and THS not only on human health, but also on the environment and ecosystems. The results of this review provide updated information on the chemical contents of MS, SS, SHS, THS, and CBs. It adds to the growing understanding that smoking creates major health problems for smokers and passive smokers, but also that it generates environmental hazards with consequences to the ecosystems and human health through discarded CBs, SHS, and THS exposure.Worldwide, about one out of two people depend on groundwater resources to satisfy their drinking water needs. While groundwater typically is of higher quality than surface water, pollution and geologic conditions may require treating groundwater to meet safe water quality criteria. Herein, a critical overview is presented of water treatment technologies for rural and underserved communities in emerging economies that depend on groundwater. Given that small to medium sized rural communities in emerging economies often lack the financial resources to support technologically complex and expensive centralized public water treatment systems, the focus is on proven technologies that are sustainable and acceptable by the rural population. After an overview of the underlying treatment mechanisms and the principal groundwater contaminants targeted by the traditional, advanced, and experimental water treatment technologies, we identify the groundwater quality parameters that may impact or interfere with the technology performance. We also introduce enabling environmental factors that might govern the implementation of water treatment technologies in the target communities and a brief discussion of safe storage of water after treatment to underline the importance of protecting the water from re-contamination. Our overview is further supported by tabulated summaries of the principal (dis)advantages of each technology covered herein, including cost considerations and social acceptance. Overall, our review suggests that underserved rural communities have sustainable and affordable options for cases where the quality of local groundwater resources requires treatment.Although filtration has been a widely applied sample pretreatment step in environmental analytical chemistry, its impact on the quality of the data produced is often underappreciated in the scientific community. The objective of this literature review and modeling exercise was to examine nine existing sorption models with input parameters including hydrophobic interactions, pH, and structural features to predict the loss of analytes during wastewater filtration due to sorption to suspended solids and to assess the impact of filtration on data quality. Models' sorption estimates were further validated with a set of comprehensive metadata collected and analyzed from 20 peer-reviewed research papers that reported physical measurements of the suspended solids sorbed fraction of analytes obtained during wastewater filtration of contaminants of emerging concern (CECs). Data on the impact of filtration were obtained from the literature for 156 organic compounds reported both for the dissolved and particulate bound analyte mass. Approximately 40% of CECs (62/156) showed significant filtration loss (>20%) as a result of the removal of suspended solids during filtration. The loss of analyte mass due to filtration ranged from 95% for acenaphthene. Collected literature data were then used to evaluate the utility of sorption modeling to predict analyte losses during sample pretreatment. Among nine sorption models, three were found to predict filtration loss of at least 70% of the CECs evaluated within a range of ±20% of the actually measured filtration loss of analytes, assuming a suspended solid concentration of 200 mg/L and a fraction of organic carbon in suspended solids of 0.43. Thus, sorption modeling can help reduce error when calculating mass loadings based on samples filtered before analysis. It is concluded that the estimates could be further improved by considering the following factors ionic interactions, characteristics of the water-borne sorbents, and filtration media properties.Plant encroachment in alpine regions, caused by global changes and human activities, has been well documented. However, our knowledge of the effects of plant encroachment on belowground microbial communities is limited. Here, we investigated soil physicochemical properties and microbial community structures under the impact of plant encroachment along an elevation gradient in the alpine tundra of the Changbai Mountain, China. We found that plant encroachment had insignificant (P > 0.05) and inconsistent effects on the α-diversity (number of observed OTUs, Shannon, Chao1, Faith's PD) of soil microbial communities. Plant encroachment indirectly influenced soil microbial community structures by altering soil physicochemical properties, which differed between elevations and plant types (P less then 0.05). In all, 40 bacterial indicator taxa and 57 fungal indicator taxa significantly shifted in response to plant encroachment, some of which were involved in soil biogeochemical cycle. Overall, our results documented the impacts of plant encroachment on soil microbial diversity and community composition, and provided a scientific basis for predicting future changes in alpine ecosystem structure and function and its subsequent feedbacks to global change.