Mercury (Hg) poses environmental and health risks due to its global distribution and high toxicity exhibited in some of its chemical forms. Although Hg is naturally present in the environment, human activities have increased its cycling among the land, atmosphere and ocean by a factor of three to five comparing the pre-industrial period to the present day. The Torviscosa chlor-alkali plant (CAP), which operated since the beginning of twentieth century, was one of the most important Cl₂ production capacity in the Northern Italy and was responsible for an uncontrolled discharge of Hg in the surrounding area. Previous studies reported the high degree of Hg pollution in soils, river sediments and surface waters of the area, but the Hg level in the atmospheric media was never taken into consideration. In this work, an integrated approach was applied with the aim to assess the level, distribution and dispersion of gaseous elemental mercury (GEM) close to the CAP area. GEM levels were monitored by means of four surveys conducted from September 2014 to July 2015, at fixed locations and covering an area of about 10 km² (including CAP area, Torviscosa village and reclaimed land), accomplished to Hg bioaccumulation measurements in selected lichens. The results indicate that the CAP area currently represents the main source of GEM in the Friuli Venezia Giulia region. The highest levels were found close to the old factory’s buildings (more than 5000 ng m⁻³), whereas other sites are less impacted. The emission of GEM is not clearly related to the intensity of solar radiation (temperature) at the soil level; however, this latter influences the release from the old buildings employed in the past for the production activities. The most important factor driving the GEM dispersion is the wind, as confirmed by the map of lichens bioaccumulation. In this context, the GEM plume partially affects the nearby village of Torviscosa (about 1 km), but the values found were always well below the international thresholds for residential areas, thus excluding the risk of inhalation for local inhabitants.

Roof runoff is an important source of urban stormwater and a main source of rainwater harvesting. Deposition of pollutants on rooftops can have a negative impact on runoff quality and, therefore, on harvested rainwater. Laboratory experiments with simulated rainfall were performed in order to study the washout of fine sand particles deposited on a ceramic tile roof, by runoff, considering the effect of the particle position, particle areal load, particle connectivity and roof slope. Results indicated that particle washout was influenced by the particle position on the roof; particle transport peak and transported mass was higher for the particle mass positions closer to the outlet. Increase in particle areal load decreased particle transport whereas particle connectivity had no effect on particle transport. However, roof slope was a dominant aspect in the particle washout; increase in roof slope greatly increased particle transport peak and transported mass. It also remarkably increased the first flush effect.

The textile industry is responsible for the disposal of a large volume of effluents containing synthetic dyes, which are considered to be highly toxic compounds for both human health and the environment. The aim of the present study was to test potential use of a renewable, low-cost product—Luffa cylindrica in disk and powder form—as adsorbent material for the treatment of textile effluents containing dyes. Saccharomyces cerevisiae cells were also immobilized on L. cylindrica to increase the adsorbent capacity. Batch experiments were conducted for the evaluation of the removal of the azo dye Direct Red 23. The Langmuir, Freundlich, and Temkin isotherms were used for a better interpretation of the data. The results showed that adsorption is more efficient at acidic pH and all adsorbent materials best fit the Langmuir model, indicating the formation of a monolayer. The isotherm results also demonstrated that the materials immobilized with the yeast had a greater sorption rate, but the cell-free L. cylindrica powder had a higher adsorbate/adsorbent interaction. The comparison with a spectrophotometrically defined standard revealed that the powder without and with yeast cells was able to achieve an acceptable removal rate of the dye from the solution. Moreover, the difference in adsorption between the powder without and with yeast cells was very small. Thus, the application of the cell-free L. cylindrica powder is economically more feasible. The findings demonstrate the potential use of L. cylindrica powder as an adsorbent for the treatment of effluents containing textile dyes.

Removal of toxic metals from aqueous solutions is of high priority in environmental chemistry. Most of the available techniques for this task are considered expensive; however, the adsorption process has been considered the easiest and the cheapest way of removing toxic metals from aqueous solution. The performance of adsorption setup largely depends on the characteristic of adsorbents. One of these characteristic is availability of large surface area. The more the available sites for chelation, the more the amount of metals removed. Therefore, the production of materials of nanoscale is expedient for adsorption purposes. Electrospinning process is one of the technologies that have been employed to produce polyacrylonitrile nanofibres (PAN-nfs). Moreover, PAN-nfs surfaces have also been chemically modified so as to introduce chelating groups such as amine, carboxyl, imines, etc. Here we review PAN-nfs as metal ion adsorbent. With characteristics such as high surface area as well as good mechanical strength, modified PAN-nfs are considered good adsorbents and have been used to remove toxic metals such as cadmium, lead, chromium, mercury, uranium, silver and copper in different ion states from their aqueous solutions. The ease of immobilization of metal-specific ligands on PAN-nfs has been of great interest in selective extraction of metal ions from their aqueous solutions. Also, toxic metals adsorbed on modified PAN-nfs can be recovered through desorption process using acids or bases of various concentrations.

Rapid increase in impervious surfaces due to urbanization often intensifies the frequency of flooding which in turn increases runoff of environmental pollutants. The Brays Bayou watershed (BBW) is a heavily urbanized and densely populated watershed located mostly in Harris County, TX. The objectives of our study are (1) to analyze and interpret the spatial and temporal land use and land cover changes in BBW and (2) to determine nutrient, heavy metal, and bacterial contamination in the Brays Bayou. Water and sediment samples were collected from selected sampling locations along the Brays Bayou and analyzed for various nutrient and metal concentrations. Bacterial analysis was conducted to enumerate the fecal coliform bacteria in water samples. Landsat Thematic Mapper (TM) satellite images sampled from over three decades (1980–2010) for the BBW study area were processed and analyzed for land use and land cover changes. Our remote sensing analysis revealed that the BBW lost about 28.4% (9463 acres) vegetation during the period of 1984 to 2010. The loss in vegetative areas resulted in increased impervious surface areas. In sediment samples, increasing trends for Al, Cu, Fe, Pb, and Zn were observed towards the downstream of Brays Bayou. Lead concentrations were found at the highest concentration (70 mg/kg) in certain Brays Bayou sampling locations. Escherichia coli concentrations decreased towards the downstream of Brays Bayou and were found below 200 maximum probable numbers/100 ml. Integration of remote sensing along with the chemical and biological analysis helped to understand the impact of land cover changes on the bayou water quality.

TiO₂ nanoparticles and nanofibers have been used to carry out a comparative study of the destruction of H₂S gas. Effects of sulphur doping have also been incorporated to assess the maximum destruction potential of the nanomaterials. An analysis has been made in this paper to evaluate and compare the performance of pure and sulphur-doped TiO₂ nanoparticles and nanofibers for the destruction of H₂S gas using photocatalysis under laboratory conditions. Regression modelling has been performed to ascertain the individual degradation rates of the nanoparticles and nanofibers. In addition, oxidation rates of H₂S gas using the nanoparticles and nanofibers have been used to further elucidate our findings. It was observed that the destruction potential of nanofibers was 10 times more as compared to nanoparticles.

Graphitic carbon nitride (g-C₃N₄) is a photocatalyst with wide application in removal of organic pollutants. In this study, we designed a porous g-C₃N₄ (p-g-C₃N₄)/8-quinolinolato iron(III) (Q₃Fe)/H₂O₂ system to enhance the organic pollutant removal efficiency by combining photocatalysis and Fenton interaction under neutral condition. The p-g-C₃N₄ was prepared through a two-step thermal oxidation reaction. Afterwards, Q₃Fe-coupled p-g-C₃N₄ was prepared by an impregnating method. The 2,4-dichlorophenol (2,4-DCP) photodegradation ratio and decomposition rate of the p-g-C₃N₄/Q₃Fe/H₂O₂ system are approximately 5 and 18 times as high as those of individual p-g-C₃N₄ system, respectively. Besides, its degradation rate is 4.3 times as high as that in the p-g-C₃N₄/H₂O₂ system. Meanwhile, Q₃Fe/g-C₃N₄ also exhibits higher activity than individual p-g-C₃N₄ in 2,4-DCP photo-decomposing. On the basis of the results of the radical trapping experiments and the Fe(II) concentration in different systems, the synergistic effect between photocatalysis and Fenton reaction is vital for the efficient pollutant degradation. The coupled system combining p-g-C₃N₄ with Q₃Fe and H₂O₂ shows potential for efficient treatment of recalcitrant organic pollutants. The combined system in this work indicated a new idea for the decomposition of organic pollutants.

In isolated areas without direct human impact where several species of seabirds nest, transformations affecting the soil come mainly from natural processes, such as chemical enrichment caused by seabirds. Penguins constitute an important bird biomass in the Southern Hemisphere, where they breed in colonies on different sites from 100 to thousands of individuals. The accumulation of trace elements and nutrients in soils within two perennial colonies of Humboldt penguins (Spheniscus humboldti) located in north western Chile and three colonies of Adélie penguins (Pygoscelis adeliae) in the Antarctic Peninsula area were investigated here. Surface soil samples were collected directly from nesting sites. Control samples were taken outside the colonies within sites adjacent to the nesting areas, but not affected by bird excrement. The contents of Cd, Co, Cr, Cu, Mo, Ni, Sr, V and Zn were determined by inductively coupled plasma optical emission spectrometry. Ammonium (NH₄) and nitrate (NO₃) ions were determined colorimetrically. Extractable potassium (K) was determined by flame emission spectrometry, and available phosphorus (Olsen-P) was determined by spectrophotometry. The highest concentrations of trace metals (Cd, Co, Cr, Cu, Mo, V and Zn) and macronutrients (available N, K and P), along with an increase in salinity and acidity levels, were found directly below the seabird colony, a situation occurring in northern Chile as well as in the Antarctic Peninsula area, highlighting the role that penguins have as bio-vectors on generating geochemical changes in different ecosystems. Some terrestrial plants and animals that live near those penguin colonies might be affected at a greater level than the organisms that live in sites similar but distant from colonies of birds. New data about the role of these species of seabirds as bio-vectors of chemical contaminants are added.

Arsenic concentrations in a drinking water reservoir system in the Eastern Ore mountains (Osterzgebirge, Germany) were observed over a 17-year period. The region experienced an environmental change during the past 20 years with decreasing acid, sulphur and nitrogen deposition and a recovering vitality of forested catchment sites. An increase of the arsenic content in the reservoir waters during that change was observed. This was caused by a diminished nitrate supply leading to lower redox potential in the sediments favouring sediment arsenic release. The recent annual cycle in the Altenberg reservoir water arsenic concentration was found to be independent from artificial aeration of the hypoxic hypolimnion during the summer stratification. However, we found a strong seasonal dependent change in water As concentration, with a maximum in autumn and a minimum in spring. The low productive system is driven by peat derived organic matter. For the recent arsenic catchment yield coherencies to dissolved organic carbon export and runoff intensity were found, indicating rising arsenic loads due to climate-related soil organic matter destabilization. Thus, in the reservoir system, both dry and wet climate conditions can increase the water As concentrations due to an internal arsenic release and a catchment arsenic import.

This paper explores the proposition that we are living in an era marked by unprecedented quantities and exotic types of human waste and environmental contamination by examining the impact of anthropogenic activity on the Earth’s epiderm. Specifically, the paper introduces anthrosols and technosols as critical markers of unfettered human activity as recorded in the terrestrial stratigraphic signature of soils and sediments adversely impacted by municipal, agricultural, industrial and maritime activities. The paper presents examples of the sources and fates of some of the most worrisome contaminants, many of them persistent organic pollutants, including common heavy metals-metalloids and hydrocarbons but also instances of more unfamiliar drug residues and antibiotic resistant genes, at Australia’s 160,000 contaminated sites.Consideration is given to how anthropogenic elements and compounds in soil may bioaccumulate and bioconcentrate in animals, and how they can subsequently be consumed to the detriment of human health. Among the 75,000 identified contaminants in Australian soils are tributyltin, which has a half-life of at least 10 years and is one of the most toxic chemicals introduced into the environment by man, and uranium-contaminated mine tailings, which require constant and careful management for up to 75,000 years if their polluting effects are to be minimized. The author concludes that anthrosols and technosols provide evidence of the Anthropocene in Australia.