Trichloroethylene (TCE) is a chlorinated aliphatic organic compound often detected as pollutant in soils and ground water. “Green technologies” based on phytoremediation were proven to be effective to reclaim organic pollutants (e.g. TCE) and heavy metals from different environmental matrices. In this work, we use Zea mays L. for the removal of high TCE concentrations from medium cultures. In particular, we investigated a sealed bioreactor where the growth medium was contaminated with an increasing amount of TCE, in the range 55–280 mg/L; the removal capability of the maize plants was assessed by means of GC-MS and LC-MS analyses. An accurate mass balance of the system revealed that the plants were able to remove and metabolise TCE with an efficiency up to 20 %, depending on the total amount of TCE delivered in the bioreactor. Morphometric data showed that the growth of Z. mays is not significantly affected by the presence of the pollutant up to a concentration of 280 mg/L, while plants show significant alterations at higher TCE concentrations until the growth is completely inhibited for [TCE] ≃ 2000 mg/L. Finally, the presence of several TCE metabolites, including dichloroacetic and trichloroacetic acids, was detected in the roots and in the aerial part of the plants, revealing that Z. mays follows the green liver metabolic model. These results encourage further studies for the employment of this plant species in phytoremediation processes of soils and waters contaminated by TCE and, potentially, by many other chlorinated solvents.

A composite catalyst for the selective catalytic reduction (SCR) of NOₓ with NH₃ is investigated, in which the rare earth (RE, including La, Ce, Pr, and Nd) is doped into manganese oxides supported on activated semi-coke (MnOₓ/ASC) via hydrothermal method at the molar ratio of Mn:RE = 1:5. It is evidenced that the addition of RE at a rather low molar ratio can enhance the catalytic activity of MnOₓ/ASC. The catalyst with a Mn:Ce molar ratio of 10:1 yields an over 90% NOₓ removal efficiency in the temperature range of 150–250 °C. An approximate 100% NO conversion and 95% N₂ selectivity are achieved at about 200 °C. The catalysts are characterized by N₂ physisorption, X-ray powder diffraction (XRD), scanning electron microscope (SEM), hydrogen temperature-programmed reduction (H₂-TPR) and X-ray photoelectron spectroscopy (XPS). The results indicated that the Ce additive is conducive to the NOₓ adsorption and then accelerates the SCR reaction due to the formation of more chemisorbed oxygen (Oᵦ), which is favored during the oxidation of NH₃ and NO. Moreover, the in situ diffused reflectance infrared Fourier transform spectroscopy (DRIFTS) results confirm that the Ce additive on MnOₓ/ASC catalyst could provide more active Brønsted acid sites, which eventually contributes to the SCR reaction. The generation of ad-NH₄ ⁺ and nitrite species is proved to play the crucial role in the promotional effect of RE addition.

Organochlorinated pesticides and Aroclors were measured in the muscle of two edible fish species (gray mullet, sea bream) and blue crab, collected from eastern Mediterranean coast in 2013. The concentration of organochlorinated pesticides (OCPs) and Aroclors in biota samples which were collected at six sites ranged from 1.0–8.6 and 9–47.5 ng g⁻¹ wet weight, respectively. Total DDT concentrations in seafood samples were compared to tolerance level established by the US Food and Drug Administration (FDA); the concentrations were detected below the tolerence level. Health risk assessment was conducted related to the consumption of chemically contaminated seafood. The estimated daily intake of OCPs calculated by using the estimated daily fish consumption in Turkey was far below the acceptable daily intake as established by FAO/WHO. Our data indicated that consumption of blue crab, gray mullet, and sea bream collected from the Mediterranean coast of Turkey could pose “no risk” for human health in terms of OCPs.

The detection of nickel in water is of great importance due to its harmfulness for living organism. A way to detect Ni is the use of whole-cell biosensors. The aim of the present work was to build a light-emitting bacterial biosensor for the detection of Ni with high specificity and low detection limit properties. For that purpose, the regulatory circuit implemented relied on the RcnR Ni/Co metallo-regulator and its rcnA natural target promoter fused to the lux reporter genes. To convert RcnR to specifically detect Ni, several mutations were tested and the C35A retained. Deleting the Ni efflux pump rcnA and introducing genes encoding several Ni-uptake systems lowered the detection thresholds. When these constructs were assayed in several Escherichia coli strains, it appeared that the detection thresholds were highly variable. The TD2158 wild-type E. coli gave rise to a biosensor ten times more active and sensitive than its W3110 E. coli K12 equivalent. This biosensor was able to confidently detect Ni concentrations as little as 80 nM (4.7 μg l⁻¹), which makes its use compatible with the norms governing the drinking water quality.

Nanomaterials have increasingly gained a great amount of interest due to their widespread applications, while their potential impacts on invertebrates in soil lack thorough investigation. This study is mainly aimed at determining the acute and subacute toxicity to the earthworm Eisenia fetida, induced by different levels of nanoscale zerovalent iron (nZVI) (100, 500, 1000 mg kg⁻¹) in natural soils. The results showed that compared to the controls, exposure to 500 and 1000 mg kg⁻¹ of nZVI significantly (P < 0.05) inhibited growth and respiration and increased avoidance response in earthworms. The perturbations of antioxidant enzyme activities (superoxide dismutase—SOD and catalase—CAT), malondialdehyde (MDA) content, and reactive oxygen species (ROS) clearly revealed that oxidative stress was induced in E. fetida exposed to nZVI. Good correlations were observed in current results among the growth, respiration, MDA, and ROS (R > 0.8; P < 0.05), and that ROS was the most sensitive parameter in response to the stress caused by nZVI. Additionally, the histopathological examination of transverse sections of the exposed earthworms passing through the body wall illustrated that there was a serious injury in epidermal tissue after an exposure of 28 days. These findings will provide a comprehensive understanding of toxicological effects of nZVI in a soil-earthworm system.

Informal E-waste recycling can pose a risk to human health and the environment which this study endeavours to evaluate. The distribution of a number of heavy metals in soil from an informal recycling site in the largest market for used and new electronics and electrical equipment in West Africa was investigated. The potential bioavailability of heavy metals, extent of contamination, potential risk due to the recycling activities and impact of external factors such as rainfall were also assessed. The concentrations of all the heavy metals tested were higher in the area where burning of the waste occurred than at the control site, suggesting an impact of the recycling activities on the soil. The order of total metal concentrations was Cu > Pb > Zn > Mn > Ni > Sb > Cr > Cd for both the dry and wet seasons. The total concentrations of Cd, Cu, Mn, Ni and Zn were all significantly higher (p < 0.001) in the dry season than in the wet season. The concentrations of Cu (329–7106 mg kg⁻¹), Pb (115–9623 mg kg⁻¹) and Zn (508–8178 mg kg⁻¹) were consistently higher than international soil guideline values. Using a sequential extraction method, the potential bioavailability of the heavy metals was indicated as Cd > Sb > Zn > Cu > Ni > Pb > Cr. When the risk was assessed using the Potential Ecological Risk Index (PERI), Cu was found to contribute the most to the potential ecological risk and Cd gave rise to the greatest concern due to its high toxic-response factor within the study site. Similarly, utilising the Risk Assessment Code (RAC) suggested that Cd posed the most risk in this site. This research establishes a high level of contamination in the study site and underscores the importance of applying the appropriate chemical speciation in risk assessment.

Urban gardening has recently experienced rapid development; however, the risk of the transfer of toxic elements from neighboring industry needs to be evaluated. We performed a multi-elemental analysis with several common edible crops (cucumber, pepper, cabbage, and lettuce) and poplar grown directly on a titanium ore landfill as a maximized scenario of exposure. Despite elevated concentrations of soil Ca, Fe, Mn, and Ti resulting from the industrial process, we did not register higher accumulation of these elements in the edible parts of crops or in poplar leaves grown on red gypsum compared with the control soil. Only S concentrations were higher in plants grown on the red gypsum, especially for cabbage. The principal component analysis among elements for plants grown on red gypsum indicated that S and Mn were accumulated by different plant species than Cd, Cu, and Zn. The poplar clone had a significantly higher transfer of S and Cr than the control and is a suitable tree species for monitoring element transfer to vegetation in this industrial context. By comparing our data with tolerable daily intake (TDI) recommendations, we demonstrated the low risk of cultivating edible crops directly on an industrial substrate in a maximized scenario of exposure, except for Cr, for which the toxicity depends on the bioavailable form. However, we did not consider the cumulative effects of the various elements because there are no current guidelines, and further research is needed to address this question.

One of the cheapest, environmentally friendly methods for cleaning an environment polluted by heavy metals is phytoextraction. It builds on the uptake of pollutants from the soil by the plants, which are able to grow under conditions of high concentrations of toxic metals. The aim of this work was to assess the possibility of growing and phytoextraction potential of Miscanthus x giganteus and Sida hermaphrodita cultivated on two different soils contaminated with five heavy metals simultaneously: Cd, Cu, Ni, Pb, and Zn. A 3-year microplot experiment with two perennial energy crops, M. x giganteus and S. hermaphrodita, was conducted in the experimental station of IUNG-PIB in Poland (5° 25′ N, 21° 58 ‘E), in the years of 2008–2010. Miscanthus was found more tolerant to concomitant soil contamination with heavy metals and produced almost double biomass than Sida in all three tested years, independent of soil type. Miscanthus collected greater amount of heavy metals (except for cadmium) in the biomass than Sida. Both energy crops absorb high levels of zinc, lower levels of lead, copper, and nickel, and absorbed cadmium at least, generally more metals were taken from the sandy soil, where plants also yielded better. Photosynthesis net rate of Miscanthus was on average 40% higher compared to Sida. Obtained results indicate that M. x giganteus and S. hermaphrodita can successfully be grown on moderately contaminated soil with heavy metals.

Water pollution is gradually increasing in natural waters through anthropogenic activities. This study aimed to use fish scales as a bio-indicator of pollution, along with water quality parameters, and the assessment and detection of selected heavy metals in water samples collected from the River Chenab, including the Chakbandi drain that gathers domestic sewage waste and industrial effluents from Faisalabad and deposits it into this freshwater body. All water quality parameters (pH, total dissolved solids (TDS), total suspended solids (TSS), salinity, conductivity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), phenols and sulphates) and concentrations of selected heavy metals (Cd, Cu, Mn, Pb and Cr) were found to be considerably higher than permissible limits as defined by the WHO, and therefore capable of causing ill health effects in aquatic organisms. Specimens of fish scales from selected fish were described qualitatively and observed quantitatively. In Catla catla, Labeo rohita and Cirrhinus mrigala, the scales showed several deformities in shape and different scale structures such as circuli, radii and annuli. In each of the three types of fish, considerable variation in the morphology of their scales was observed in specimens collected from polluted sites.