This study investigated selected trace elements toxicity in sea turtles Caretta caretta population from Baja California Sur (BCS), Mexico, by analyzing associations among Zn, Se, Cu, As, Cd, Ni, Mn, Pb, and Hg with various biochemical parameters (packed cell volume, leukocytes, and selected blood parameters), and whether their concentrations could have an impact on the health status of sea turtles. Blood samples from 22 loggerhead (C. caretta) sea turtles from BCS, Mexico, were collected for trace elements on biochemistry parameter analyses. Significant associations among trace element levels and the biochemistry parameters were found: Cd vs ALP (R ² = 0.874, p ˂ 0.001), As vs ALP (R ² = 0.656, p ˂ 0.001), Mn vs ALP (R ² = 0.834, p ˂ 0.001), and Ni vs LDH (R ² = 0.587, p ˂ 0.001). This study is the first report of the biochemical parameters of the North Pacific loggerhead sea turtle (C. caretta) from Baja California Sur, Mexico, and it is the first to observe several associations with toxic and essential trace elements. Our study reinforces the usefulness of blood for the monitoring of the levels of contaminating elements and the results suggest that, based on the associations with health clinical parameters, high levels of Cd and As could be representing a risk to the North Pacific loggerhead population health.

In this work, visible light-responsive carbon nanotubes (CNTs)/Bi₄VO₈Cl composite photocatalysts have been prepared by a facile in situ hydrothermal method and characterized by various techniques. The photocatalytic properties of the photocatalysts are evaluated by the degradation of refractory azo-dye methyl orange (MO), hexavalent chromium Cr(VI), and bisphenol A (BPA) in water under visible light irradiation. It is found that the as-prepared composite with 4 wt% CNTs shows an optimal photocatalytic performance, and its photocatalytic activity is 30% higher than that of pure Bi₄VO₈Cl. The enhanced photocatalytic activity is ascribed to the synergetic effects induced by increased light absorption, increased adsorption efficiency for pollutant, and suppressed recombination rate of photogenerated charge carriers. Furthermore, efficient removals of Cr(VI), bisphenol A (BPA), and combined contamination of Cr(VI) and BPA over CNTs/Bi₄VO₈Cl composite further confirm that the degradation of organic pollutants is a photocatalytic mechanism rather than photosensitization of dye. Of particular importance is that removal efficiency of single pollutant can be promoted by the coexistence of the Cr(VI) and organics. The mechanism of synergetic promotion is discussed and attributed to the accelerated separation of charge carriers resulted from their simultaneously being captured by pollutants. Moreover, the CNTs/Bi₄VO₈Cl composite exhibits good stability and recycling performance in the photocatalytic degradation process. Therefore, the composite photocatalysts developed in the present work are expected to have the potential in purification of complex wastewater. Graphical abstract The separation of photogenerated charge carriers and adsorbing capacity as well as visible light absorption ability of Bi₄VO₈Cl are significantly promoted by coupling with carbon nanotubes. Simultaneous removal of Cr(VI) and organic pollutants can be achieved by CNTs/Bi₄VO₈Cl composite photocatalysts under visible light irradiation.

Manipulation of bio-technological processes in treatment of dyestuffs has attracted considerable attention, because a large proportion of these synthetic dyes enter into natural environment during synthesis and dyeing operations that contaminates different ecosystems. Moreover, these dyestuffs are toxic and difficult to degrade because of their synthetic origin, durability, and complex aromatic molecular structures. Hence, bio-assisted phytoremediation has recently emerged as an innovative cleanup approach in which microorganisms and plants work together to transform xenobiotic dyestuffs into nontoxic or less harmful products. This manuscript will focus on competence and potential of plant-microbe synergistic systems for treatment of dyestuffs, their mixtures and real textile effluents, and effects of symbiotic relationship on plant performances during remediation process and will highlight their metabolic activities during bio-assisted phytodegradation and detoxification.

Dust is an environmental, geotechnical, health, and economical hazard. Fugitive dust emanating along transportation systems such as roads, railways, and airports especially can have significant impacts on health, safety, material loss, cost of maintenance, and interfere with the facilities. Quantitative studies on the effectiveness of the proper dust palliatives and their environmental impact have been studied with a number of biological and chemical methods. The objective of this study was to establish a method for using the microbial Induced calcium carbonate precipitation (MICP) approach to reduce the percent of mass loss against erosive force of wind regarding to the concentration and characteristics of aggregate used, climate, and traffic amounts. The results of this study showed that the required precipitation for dust control of sand by 70% is less than 15 g CaCO₃/m² between sand grains in bio-treated sand. The wind tunnel test results of this study also indicate that the effectiveness of the bio-treatment method for dust control depends on many variables, such as the percent of precipitated calcium carbonate and tensile strength.

Application of maize straw and biochar can potentially improve soil fertility and sequester carbon (C) in the soil, but little information is available about the effects of maize straw and biochar on the mineralization of soil C and nitrogen (N). We conducted a laboratory incubation experiment with five treatments of a cultivated silty loam, biochar produced from maize straw and/or maize straw: soil only (control), soil + 1 % maize straw (S), soil + 4 % biochar (B1), soil + 4 % biochar + 1 % maize straw (B1S), and soil + 8 % biochar + 1 % maize straw (B2S). CO₂ emissions, soil organic C, dissolved organic C, easily oxidized C, total N, mineral N, net N mineralization, and microbial biomass C and N of three replicates were measured periodically during the 60-day incubation using destructive sampling method. C mineralization was highest in treatment S, followed by B2S, B1S, the control, and B1. Total net CO₂ emissions suggested that negative or positive priming effect may occur between the biochar and straw according to the biochar addition rate, and biochar mineralization was minimal. By day 35, maize straw, irrespective of the rate of biochar addition, significantly increased microbial biomass C and N but decreased dissolved organic N. Biochar alone, however, had no significant effect on either microbial biomass C or N but decreased dissolved organic N. Mixing the soil with biochar and/or straw significantly increased soil organic C, easily oxidized C and total N contents, and decreased dissolved organic N content. Dissolved organic C contents showed mixed results. Notably, N was immobilized in soil mixed with straw and/or biochar, but the effect was stronger for soil mixed with straw, which may cause N deficiency for plant growth. The application of biochar and maize straw can thus affect soil C and N cycles, and the appropriate proportion of biochar and maize straw need further studies to increase C sequestration.

We studied the possible metal offloading onto the progeny of three pregnant female ragged-tooth sharks (Carcharias taurus) (C. taurus). The presences of five metals, i.e. aluminium (Al), arsenic (As), cadmium (Cd), lead (Pb) and selenium (Se) were validated by mass spectrometry in the maternal plasma as well as the intracapsular and uterine fluids (UF) in which embryos develop. Metals were ranked in a decreasing concentration as follows: Plasma: As > Al > Se > Pb > Cd; ICF: As > Se > Al > Cd > Pb and UF: As > Se > Al > Cd > Pb. As was present in the highest concentration in all three sharks. Al, Pb and Cd were found to be the highest within the plasma, while concentrations of Se were similar in all three fluids. These results indicate that C. taurus embryos are exposed to metals during early development, but the impact of this exposure remains unknown. To the best of our knowledge, this is the first investigation to confirm the presence of metals in the fluids that surround the developing C. taurus embryos, a species that is already listed as vulnerable.

The present research explains environmental performance using an ecological composite index as the dependent variable and focusing on two national dimensions: sociopolitical characteristics and economics. Environmental performance is measured using the Composite Index of Environmental Performance (CIEP) indicator proposed by García-Sánchez et al. (2015). The first model performs a factor analysis to aggregate the variables according to each analyzed dimension. In the second model, the estimation is run using only single variables. Both models are estimated using generalized least square estimation (GLS) using panel data from 152 countries and 6 years. The results show that sociopolitical factors and international trade have a positive effect on environmental performance. When the variables are separately analyzed, democracy and social policy have a positive effect on environmental performance while transport, infrastructure, consumption of goods, and tourism have a negative effect. Further observation is that the trade-off between importing and exporting countries overshadows the pollution caused by production. It was also observed that infrastructure has a negative coefficient for developing countries and positive for developed countries. The best performances are in the democratic and richer countries that are located in Europe, while the worst environmental performance is by the nondemocratic and the poorest countries, which are on the African continent.

In this paper, Fe₃O₄@graphene (Fe₃O₄@G) magnetic nanocomposite was prepared via in situ precipitation method for the removal of oxytetracycline (OTC) and tetracycline (TC) from aqueous solution. The properties of the prepared nanocomposite were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and magnetic property measurement system (MPMS). Adsorption isotherm and kinetics of OTC and TC were studied in batch experiments. The influence of the dosage of Fe₃O₄@G, the solution pH, and ion strength on the adsorption process were also assessed. The results demonstrated that the Langmuir model fitted the adsorption equilibrium data better than did the Freundlich model, and the pseudo-first-order model was more suitable than the pseudo-second-order to describe the adsorption process, with a good adsorption rate constant (k = 0.974 and 0.834 g mg⁻¹ h⁻¹, respectively). The adsorption ability reached maximum at pH of 7 with no NaCl. The removal efficiency of Fe₃O₄@G in lake, tap, and pool water were 95.45, 96.68, and 89.82 % for OTC and 98.77, 98.23, and 89.09 % for TC, respectively. The π-π interaction and cation-π bonding of the adsorbent and analytes make it suitable for the removal of OTC and TC. The present study suggests that the prepared composite can be deemed as a promising material for the removal of tetracycline antibiotics from aqueous solution.

Surface water samples were collected from 20 sampling sites throughout the Ganjiang River during pre-monsoon, monsoon, and post-monsoon seasons, and the concentrations of dissolved trace elements were determined by inductively coupled plasma-mass spectrometry (ICP-MS) for the spatial and seasonal variations, risk assessment, source identification, and categorization for risk area. The result demonstrated that concentrations of the elements exhibited significant seasonality. The high total element concentrations were detected at sites close to the intensive mining and urban activities. The concentrations of the elements were under the permissible limits as prescribed by related standards with a few exceptions. The most of heavy metal pollution index (HPI) values were lower than the critical index limit, indicating the basically clean water used as habitat for aquatic life. As was identified as the priority pollutant of non-carcinogenic and carcinogenic concerns, and the inhabitants ingesting the surface water at particular site might be subjected to the integrated health risks for exposure to the mixed trace elements. Multivariate statistical analyses confirmed that Zn, As, Cd, and Tl were derived from mining and urban activities; V, Cd, and Pb exhibited mixed origin; and Co, Ni, and Cu mainly resulted from natural processes. Three categorized risk areas corresponded to high, moderate, and low risks, respectively. As a whole, the upstream of the Ganjiang River was identified as the high-risk area relatively.