Edible muscle tissues of Solea solea, Mullus barbatus, and Sardina pilchardus marketed in Mersin were analyzed for their Cr (total), Mn, Fe, Ni, Cu, Zn, As (total), Cd, Sn, and Pb levels. Metal levels of the tissues were determined using inductively coupled plasma-mass spectrophotometric (ICP-MS) methods. Muscle levels of Cr, Mn, Fe, Ni, Cu, Zn, As, Sn, and Pb were determined as 0.19–2.80, 0.08–3.88, 0.93–25.76, 0.03–0.63, 0.01–1.96, 1.28–45.95, 0.49–25.26, 0.14–4.03, and 0.02–1.37 mg kg⁻¹ w.w., respectively. Cadmium levels were below detection limits in all the muscle samples taken. Mean metal levels of the tissues were compared with the provisional tolerable daily (PTDs) and weekly (PTWIs) intake limits. Mean metal levels taken by the consumption of analyzed tissues were below PTDs and PTWIs; hence, the fish species studied do not pose any risk for human consumption from the point of heavy metals.

This study was carried out to examine heavy metal accumulation in rice grains and brassicas and to identify the different controls, such as soil properties and soil heavy metal fractions obtained by the Community Bureau of Reference (BCR) sequential extraction, in their accumulation. In Guangdong Province, South China, rice grain and brassica samples, along with their rhizospheric soil, were collected from fields on the basis of distance downstream from electroplating factories, whose wastewater was used for irrigation. The results showed that long-term irrigation using the electroplating effluent has not only enriched the rhizospheric soil with Cd, Cr, Cu, and Zn but has also increased their mobility and bioavailability. The average concentrations of Cd and Cr in rice grains and brassicas from closest to the electroplating factories were significantly higher than those from the control areas. Results from hybrid redundancy analysis (hRDA) and redundancy analysis (RDA) showed that the BCR fractions of soil heavy metals could explain 29.0 and 46.5 % of total eigenvalue for heavy metal concentrations in rice grains and brassicas, respectively, while soil properties could only explain 11.1 and 33.4 %, respectively. This indicated that heavy metal fractions exerted more control upon their concentrations in rice grains and brassicas than soil properties. In terms of metal interaction, an increase of residual Zn in paddy soil or a decrease of acid soluble Cd in the brassica soil could enhance the accumulation of Cd, Cu, Cr, and Pb in both rice grains and brassicas, respectively, while the reducible or oxidizable Cd in soil could enhance the plants’ accumulation of Cr and Pb. The RDA showed an inhibition effect of sand content and CFO on the accumulation of heavy metals in rice grains and brassicas. Moreover, multiple stepwise linear regression could offer prediction for Cd, Cu, Cr, and Zn concentrations in the two crops by soil heavy metal fractions and soil properties.

Saline melt water from road salt applications that has percolated into a fine sandy soil in winter is rinsed out of the soil by infiltrating rainwater in the following warmer seasons. This sequence of saturated and unsaturated flow processes associated with saline water transport in a fine sandy soil was studied by simulation and exploratory laboratory experiments. Experiments in soil columns of 300-μm sand revealed that two rinses of pure water, each of one pore volume, were sufficient to reduce the salt concentration by 99% of its original value in the soil column. Simulated time variations of salt concentration in the effluent from the column agreed with experimental results. Based on simulated and experimental results, a sandy soil must become saturated to experience pore water flow in order to efficiently rinse saline snowmelt water. Depending on the saturated hydraulic conductivity and the soil depth, days, weeks, or months of freshwater infiltration in summer are needed to rinse saline melt water from an unsaturated sandy soil after road salt applications in winter. This explains findings of significant salt concentrations in surface and shallow groundwater during summer months, long after road salt application and infiltration has ceased.

The aim of this study was to investigate the presence of heavy metals/metalloids (Pb, Cd, Hg, Cu, Fe, Zn, As) in the muscle tissue of fish from the Danube River (two locations: Zemun and Grocka). For the purpose of heavy metal determination in fish muscle, 120 samples of six different fish species, Prussian carp, barbel, bream, carp, pike perch, and catfish were collected. For determining heavy metals, we used microwave oven digestion and atomic absorption spectrometer methods. The highest average content of Pb (0.084 ± 0.004 mg kg⁻¹), Cd (0.082 ± 0.003 mg kg⁻¹), Hg (0.466 ± 0.006 mg kg⁻¹), and As (0.333 ± 0.007 mg kg⁻¹) was found in the muscle of carp (an omnivorous fish) from Grocka, while the highest average level of Fe (13.60 ± 0.03 mg kg⁻¹) was deposited in bream (also omnivorous) from Zemun. Also, the average Cu level (1.62 ± 0.13 mg kg⁻¹) was the highest in catfish muscle (a carnivorous fish) from Grocka, while the highest Zn content (11.16 ± 0.17 mg kg⁻¹) was determined in muscle of Prussian carp (an omnivorous fish) from Zemun. The highest content of heavy metals (Cu, Fe, and Zn, respectively) in muscle of the six different types of fish from both locations was symmetrically arranged by species (catfish, barbel, and Prussian carp, respectively). Concentrations of Pb, Hg, and As in the Danube River fish muscle were under the maximum residual levels prescribed by the European Union (EU) and the maximum allowed concentrations (MAC) for Serbia. On the other hand, in all fish muscle from both locations (Zemun and Grocka), higher concentrations of Cd than prescribed (MAC) were found, with the exception of bream and pike perch.

Spontaneous colonization of mine tailing dams by plants is a potential tool for phytostabilization of such reservoirs. However, the physical and chemical properties of each mine tailings deposit determine the success of natural plant establishment. The plant Baccharis linearis is the main native nanophanerophyte species (evergreen sclerophyllous shrub) that naturally colonizes abandoned copper tailings dams in arid to semiarid north-central Chile. This study compare growth of B. linearis against the physical and chemical properties of a Technosol derived from copper mine tailings. Five sites inside the deposit were selected based on B. linearis vegetation density (VD), at two soil sampling depths under the canopy of adult individuals. Physical and chemical properties of tailings samples and nutrient concentrations in tailings and plants were each determined. Some morphological features of the plants (roots and aerial parts) were also quantified. There were significant differences in soil available water capacity (AW) and relative density (Rd) at different VD. Sites with low AW and high Rd had lower nutrient concentrations and higher Zn content in tailings, decreased infection by arbuscular mycorrhizal fungi, and increased fine root abundance and root hair length in individual plants. In contrast, higher AW, which was positively correlated with fine particles and organic matter content, had a positive effect on vegetation coverage, increased N and P contents in tailings, and increased N contents in leaf tissues, even when available N and P levels in tailings were low. Multiple constraints, such as low AW, N, P, and B contents and high Zn concentrations in the tailings restricted vegetation coverage, but no phenotypic differences were observed between individuals. Thus, in order to promote dense coverage by B. linearis, water retention in these tailings must be improved by increasing colloidal particles (organic and/or inorganic) contents, which have a positive effect on colonization by this species.

With the increase in the occurrence of heavy metal polluted rice in Asian countries, food safety of rice products is of utmost concern to consumers. The current study discusses the distribution of trace elements Cr, Cu, Zn, As, Se, Cd, Hg, and Pb in Asian rice-derived food products. Three types of food products, rice noodles, rice vinegar/wine, and rice snacks, were chosen for examination. Most toxic heavy metals and metalloid such as As, Cd, Hg, and Pb were found to be within the safe level of EPA. Since rice vinegar/wine is not the staple food for people, there is no noticeable safety concern. Rice noodles and snacks are consumed with noticeable Se content and they are possible for human Se source addition. With comparison with raw rice, rice-derived food products showed better quality in terms of toxic heavy metals and metalloids. This study is for the first time reporting a thorough understanding of safety concern of rice-derived food products. It provides baselines and understanding on current levels of trace elements and heavy metals in Asian-derived rice products as affected by food processes. It would also help consumers build up confidence on the food safety of Asian rice products.

This study describes the immobilization of ginger peroxidase on amino-functionalized silica-coated titanium dioxide nanocomposite and its application in bioremediation process. A dramatic enhancement in enzyme activity was observed after immobilization on nanosupport which was evident from the effectiveness factor (η) value of 1.76. Immobilization of enzyme on nanosupport was confirmed by transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. Immobilized peroxidase exhibited higher activity in a broad range of pH and temperature as compared to free enzyme. Also, the thermostability of peroxidase was strikingly improved upon immobilization. After six repeated uses, the immobilized peroxidase retained around 62% of its dye decolorization activity. V ₘₐₓ of the enzyme was changed to 35.01 μmol L⁻¹ min⁻¹ from 8.42 μmol L⁻¹ min⁻¹ after immobilization on nanocomposite, which was a fourfold increase as compared to the free enzyme. Circular dichroism spectroscopy demonstrated conformational changes in the secondary structure of the enzyme, a possible reason for the enhanced enzyme activity after immobilization. Immobilized peroxidase was highly efficient in the removal of acid yellow 42 dye in a stirred batch process, i.e., 90% of the dye was decolorized within 1.5 h as compared to the free enzyme decolorizing only 69% of the dye in the same period. Our results clearly demonstrate that this nanobioconjugate with enhanced catalytic activity, high stability, and very good reusability has remarkable potential for the treatment of aromatic pollutants present in wastewater. Graphical Abstract Schematic representation of immobilization of ginger peroxidase on amino functionalized silica coated titanium dioxide nanocomposite and its use in dye decolorization process.

In order to determine the possible impact on the marine environment, we present a study on the dispersal and bioavailability of sediment-associated heavy metals related to underwater blasting and dredging of bedrock operations during a quay construction. The environmental impact was primarily assessed by deploying a buoy setup including sediment traps, blue mussels, and passive samplers (diffusive gradient in thin films, DGTs) in a gradient from the construction site during the operations. Samplings were made during five separate periods covering a total span of about 2.5 months. Analyses included sedimentation rates, organic content, and metal concentrations of the material collected in the sediment traps and metal concentrations of the mussels and passive samplers. The construction work was associated with a considerable dispersion of sediments, organic material, and associated heavy metals. The major fraction of the sediment settled in the vicinity of the construction site. While the mussels were found to accumulate some metals in a distance-related manner to the construction site and no such accumulation in the DGTs occurred, we conclude that most of the dispersed metals were particle associated. It was found that while a large part of the material settled in the vicinity of the construction site, most of the fine-grained and/or organic sediment that was brought into suspension was transported further away from the construction site (beyond the 350 m) most likely carrying contaminants including heavy metals. For future studies of risks and monitoring of underwater blasting and dredging, we recommend to include a larger monitoring area and more importantly water samples of the suspended plumes. Graphical Abstract The dispersal of sediments and bioavailability of heavy metals were assessed using a buoy setup during underwater blasting and dredging. ᅟ

A treatment system combining the coal-based carbon membrane with electrochemical oxidation process was designed for the enhanced microalgae removal from simulated ballast water. The effects of various parameters including microalgae species, microalgae density, electric field intensity, and electrical conductivity on the separation performance were carried out. Fouling test was further performed for assessing the antifouling ability of the treatment system. The results showed big microalgae species tended to form a thick fouling layer on the carbon membrane, resulting in low permeate flux. High microalgae density gave rise to serious membrane fouling, which decreases the permeate flux. The treatment system showed enhanced permeate flux and fouling resistance by coupling with electrochemical oxidation process. High conductivity favored the electrochemical reactions on the surface of the carbon membrane, which reduces the clogging of the microalgae to the carbon membrane. After cleaning, the treatment system still kept high permeate flux, implying its good regeneration ability.

Modification of a catalyst with polyethylene glycol (PEG) created a dramatic increase in the catalytic activity for the degradation of phenol wastewater. The Fe/PEG-modified γ-Al₂O₃ catalyst was prepared by an impregnation method. The as-prepared catalyst was characterized by X-ray photoelectron spectroscopy, wide- and small-angle X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and N₂ adsorption-desorption experiments, and the results showed that the Fe species were highly dispersed on the surface of the PEG-modified support. At the same time, the PEG modification resulted in an increase in the Brunauer-Emmett-Teller surface area and pore volume. The catalytic activity test showed that the Fe/PEG-modified γ-Al₂O₃ catalyst exhibited a superior performance for the degradation of phenol wastewater in this study, and the phenol and COD removal values reached 94.1 and 88.9%, respectively, within 60 min. The results clearly show that PEG modification is a promising methodology for the preparation of a catalyst with good dispersal of the active component on the support.