In the present study, the 16S-rRNA sequencing of heavy metal-resistant and susceptible bacterial strains isolated from the industrial and agriculture soil showed resemblance with Pseudomonas taiwanensis. Based on the growth rate, two bacterial strains SJPS_KUD54 and KUD-MBBT4 exhibited 10 ppm tolerance to Arsenic and Cadmium. These two heavy metals caused, a significant increase in stress enzymes like superoxide dismutase, catalase and glutathione S-transferase activities in SJPS_KUD54 when compared to KUD-MBBT4. Following heavy metal treatment, the atomic-force-microscopy observations showed no change in the cell-wall of SJPS_KUD54, whereas the cell-wall of KUD-MBBT4 got ruptured. Moreover, the protein-profile of SJPS_KUD54 treated with heavy metals exhibited varied patterns in comparison with untreated control. In addition, the accumulation of hydroxyl, thiol and amides were found in the SJPS_KUD54 relative to its control. Furthermore, the resistant SJPS_KUD54 strain showed a remarkable bioaccumulation properties to both Arsenic and Cadmium. Thus, it is inferred that the growth rate, stress enzymes and functional-groups play a significant role in the physiological-adaption of SJPS_KUD54 during stress conditions, which is positively involved in the prevention or repair mechanism for reducing the risks caused by heavy metal stress.

Data from National Health and Nutrition Examination Survey for 2013–2016 were used to compare observed levels of cadmium, lead, and total mercury in blood among US residents aged ≥12 years who were users of cigars, cigarettes, cigars and cigarettes, e-cigarettes and dual users of cigarettes and e-cigarettes. Total sample size available for analysis was 1139. Adjusted geometric means (AGM) among cigarette, cigar, e-cigarette, cigarette and cigar, and cigarette-e-cigarette users were comparable for blood cadmium lead, and total mercury. Cigar only users had lower AGM than cigar and cigarette users for total mercury (0.56 vs. 0.97 μg/L, p = 0.03). There is no evidence yet that can show concentrations of blood and urine cadmium, lead, and mercury among e-cigarette users are any different than among cigarette and/or dual users of cigarettes and e-cigarettes.

Interaction mechanisms of tetracycline (TC, as a typical antibiotic) on polystyrene microsphere (PSs, as a typical nanoplastic) were conducted by the batch, spectroscopic and theoretical techniques. The batch results showed that Na+ and K+ had no obvious effects on TC adsorption towards PSs, whereas Mg2+ significantly inhibited TC adsorption at pH > 5.0 due to its induced aggregations of PSs. The maximum TC adsorption capacity of PSs in the presence of humic acid (50.99 mg/g) was higher than that of PSs (44.77 mg/g) at pH 6.0. The highly effective adsorption was attributed to electrostatic attraction, π-π interaction and hydrophobic effect, which was determined by FT-IR and XPS analysis. According to DFT (density functional theory) calculations, the adsorption energy of TC/TC+ on PSs (1.52 eV) was significantly higher than that of negative TC− (0.57 eV), whereas minimum distance of TC on PSs (3.684 Å) was shorter than that of TC− on PSs (3.988 Å). The results of theoretical calculations indicated that TC was more preferably adsorbed on PSs with more stable configuration compared to TC−. These findings indicated that PSs can be used as a promising adsorbent for immobilization and pre-concentration of TC from aqueous solutions.

This study examined to what degree bioaccumulated pesticides in transplanted zebra mussels can give an insight to pesticide bioavailability in the environment. In addition, it was investigated if pesticide body residues could be related to ecological responses (changes in macroinvertebrate community composition). For this at 17 locations, 14 pesticide concentrations and nine dissolved metals were measured in translocated zebra mussels and the results were related to the structure of the macroinvertebrate community. Critical body burdens in zebra mussel, above which the ecological status was always low, could be estimated for chlorpyrifos, terbuthylazine and dimethoate being respectively 8.0, 2.08 and 2.0 ng/g dry weight.With multivariate analysis, changes in the community structure of the macroinvertebrates were related to accumulated pesticides and dissolved metals. From this analysis, it was clear that the composition of the macroinvertebrate communities was not only affected by pesticides but also by metal pollution. Two different regions could be clearly separated, one dominated by metal pollution, and one where pesticide pollution was more important.The results of this study demonstrated that zebra mussel body burdens can be used to measure pesticide bioavailability and that pesticide body burdens might give insight in the ecological impacts of pesticide contamination. Given the interrelated impacts of pesticides and heavy metals, it is important to further validate all threshold values before they can be used by regulators.

Nitrogen is one of the most significant pollutants in the Yangtze River estuary (YRE), China. Reliable estimation of nitrogen concentration in the water is crucial for assessment of the water quality of the estuary. Because ocean fronts exist in the YRE, which divide water masses into different regions, it is necessary to account for the heterogeneity of the water surface when predicting nitrogen concentrations. A new geostatistical method, called spatiotemporal point mean of surface with non-homogeneity (ST-PMSN), is proposed to model the non-stationary spatiotemporal random process of nitrogen concentrations between 2004 and 2013 in the YRE. The method considers the spatiotemporal correlation of surface water nitrogen and uses information from both sides of a boundary for heterogeneous water masses. Comparing with several other interpolating methods, including spatial ordinary kriging (OK), stratified ordinary kriging (SOK), point mean of surface with non-homogeneity (P-MSN), spatiotemporal ordinary kriging (STK), and stratified spatiotemporal ordinary kriging (SSTK), the cross-validation results show that ST-PMSN has the highest accuracy, followed by SSTK, STK, P-MSN, SOK, and OK in descending order. ST-PMSN is therefore demonstrated to be effective in estimating the nitrogen pollutant concentrations in a stratified estuary. According to interpolated nitrogen concentrations in the YRE, water quality has generally deteriorated—with fluctuations—from 2004 to 2013. The average annual reduction in area of water quality of Grades I and II from 2004 to 2013 was 1.10%. At the same time, the average annual increase in area of water quality of Grades III and IV was 0.89% and that of Grade V was 0.21%. The results of this study provide a new and more accurate interpolating method for assessing the pollutant concentration in the marine and offers guidance for more precise classification of water quality in the YRE.

Dissolved organic matter (DOM) occurs ubiquitously in aquatic environments and plays an intrinsic role in altering the chemical speciation and toxicity of methylmercury (MeHg). However, interactions between MeHg and natural DOM remain poorly understood, especially at the functional group level. We report here the mitigative effects of three natural organic matter (NOM) and five model-DOM under different concentrations (0, 1, 3, 10, 30 and 100 mg-C/L) on the toxicity of MeHg in embryonic zebrafish (<4 h post-fertilization, hpf). NOM are those from the Mississippi River, Yukon River, and Suwannee River, while model-DOM include those containing thiosalicylic acid, L-glutathione, dextran, alginic acid, and humic acid. We selected a MeHg concentration (100 n-mol/L) that reduces the survival rate of embryos at 24 hpf by 18% and increases malformations at 72 and 96 hpf. In the presence of DOM, however, the malformation rates induced by MeHg can be mitigated to a different extent depending on DOM concentrations, specific functional groups, and/or specific components. Model DOM with aromatic thiols was the most effective at mitigating the effects of MeHg, followed by L-glutathione, carbohydrates, and humic acid. NOM also mitigated the toxicity of MeHg dependent on their composition and/or effective DOM components as characterized by fluorescence excitation-emission matrix techniques. Specifically, humic-like DOM components are more effective in reducing the MeHg toxicity in the embryonic zebrafish compared to protein-like components. Further studies are needed to elucidate the interactions between DOM and MeHg and the mitigative mechanisms at the molecular level.

Heavy metal contamination is widespread in Bangladesh. Previous studies have observed lead increases blood pressure over time. However, the role of other metal contaminants and essential micronutrients, which could also adversely affect blood pressure or act as protective factors, is understudied.We therefore evaluated the associations of lead, manganese, and selenium with blood and pulse pressure trajectories.We prospectively followed placebo-assigned participants nested within a randomized trial for the prevention of arsenic-related skin cancer (n = 255). Blood lead, manganese, and selenium were measured at baseline; blood pressure was measured at baseline and at 3 biennial follow-up examinations. Mixed-effect linear regression models were used to estimate associations with average annual changes in systolic, diastolic, and pulse pressure.In models simultaneously adjusted for baseline blood lead, manganese, and selenium concentrations in addition to other potential confounders, lead was linearly associated with increases in systolic blood pressure, but not with diastolic blood pressure or pulse pressure. A non-linear association was observed for manganese, such that mid-range concentrations were associated with decreases in systolic, diastolic, and pulse pressure. Baseline selenium concentrations in the highest quartile were also associated with longitudinal decreases in both systolic and diastolic blood pressure, while null associations were observed with pulse pressure. In exploratory analyses, the combination of mid-range manganese and high selenium concentrations completely offset lead-associated increases in blood and pulse pressure.The results indicate a direct, linear association of lead exposure with systolic blood pressure, and manganese and selenium exposures within certain ranges may have a blood pressure-lowering effect in this population.

Epidemiological evidence suggests that phthalate plasticizers may act as “obesogens”, which are chemicals that exacerbate obesity. The gastrointestinal (GI) system is the primary exposure route for phthalates, however, the relationship between phthalate-driven perturbations of GI system functions that can influence obesity has yet to be examined. To address this knowledge gap, we exposed Danio rerio (zebrafish) for 60 days to either (1) Control feeding (5 mg/fish/day), (2) Overfeeding (20 mg/fish/day) or (3) Overfeeding with diethyl-hexyl phthalate (DEHP) (20 mg/fish/day with 3 mg/kg DEHP). After 60 days, Overfed and Overfed + DEHP zebrafish had elevated body mass, and hepatosomatic and gonadosomatic indices. RNAseq analysis of the GI revealed enrichment of gene networks related to lipid metabolism in the Overfed + DEHP group. Many of the enriched networks were under transcriptional control of peroxisome proliferator activated receptor alpha (pparα), a known modulator of lipid metabolism, immune function, and GI function. Real-time PCR confirmed that pparα was overexpressed in the Overfed + DEHP zebrafish, further revealing a pathway by which DEHP may influence lipid metabolism via the GI. These data increase our understanding of phthalate-driven effects on GI function and lipid metabolism, identifying gut-specific gene networks that may drive phthalate-exacerbated obesity.

The toxic sensitivity in different physiological levels of chromium (Cr) contaminated soils with environmentally equivalent concentrations (EEC) was fully unknown. The earthworm Eisenia fetida was exposed to a Cr-contaminated soil at the EEC level (referred to as Cr-CS) to characterize the induced toxicity at the whole body, organ, tissue, subcellular structure and metabolic levels. The results showed that the survival rate, weight and biodiversity of the gut microorganisms (organ) had no significant difference (p > 0.05) between control and Cr-CS groups. Qualitative histopathological and subcellular evaluations from morphology showed earthworms obvious injuries. The organelle injuries combined with the metabolic changes provided additional evidence that the Cr-CS damaged the nucleus and probably disturbed the nucleic acid metabolism of earthworms. 2-hexyl-5-ethyl-3-furansulfonate, dimethylglycine, betaine and scyllo-inositol were sensitive and relatively quantitative metabolites that were recommended as potential biomarkers for Cr-CS based on their significant weights in the multivariate analysis model. In addition, the relative abundance of Burkholderiaceae, Enterobacteriaceae and Microscillaceae of the earthworm guts in the Cr-CS group significantly increased, particularly for Burkholderiaceae (increased by 13.1%), while that of Aeromonadaceae significantly decreased by 5.6% in contrast with the control group. These results provided new insights into our understanding of the toxic effects of the EEC level of Cr contaminated soil from different physiological levels of earthworms and extend our knowledge on the composition and sensitivity of the earthworm gut microbiota in Cr contaminated soil ecosystems. Furthermore, these toxic responses from gut microorganisms to metabolites of earthworms provided important data to improve the adverse outcome pathway and toxic mechanism of the Cr-CS if the earthworm genomics and proteomics would be also gained in the future.

Microsorum pteropus is a novel potential Cd (cadmium) aquatic hyperaccumulator. In the present study, hydroponic experiments were conducted to assess the accumulation and subcellular distribution of Cd in the root, stem and leaf of M. pteropus. SEM (scanning electron microscopy) – EDX (energy dispersive X-ray fluorescence spectrometer) and TEM (transmission electron microscopy) were used to observe the ultrastructure of different tissues under 500 μM Cd exposure. After exposure to 500 μM Cd for 7 days, the root, stem and leaf of M. pteropus can accumulate to be > 400 mg/kg Cd in dry mass with no significant influence on the growth. In the root and leaf of M. pteropus, the Cd was more likely to store in the cell wall fraction. However, Cd in the stem was mainly stored in both the cell wall fraction and the cytoplasm fraction. Under SEM observation and EDX detection, 1) Cd was found to be sequestrated in the epidermis or chelated in the root cells, 2) no significant deposit spots were observed in the stem, 3) Cd was found in the trichome of the leaf, and the sporangium was not damaged. TEM observations revealed 1) possible Cd precipitations in the root cell and 2) no significant ultrastructure variation in the stem, and 3) the chloroplast retained its structure and was not affected by the Cd. M. pteropus showed great capacity for Cd accumulation without influencing growth. In addition, the ultrastructure of all the tissues was not damaged by the Cd. M. pteropus showed a great potential in phytoremediation in heavy metal polluted water solutions, and may provide new directions for the study of resistance mechanisms of aquatic hyperaccumulators.