Peatlands are often regarded as metal repositories, but under drought conditions may switch from sinks to sources of metals and contaminate downstream ecosystems. To evaluate whether the release of metals into soil solution in peatlands is predictable using simple, widely available soil parameters, six peatlands, with varying levels of metal contamination, including a previously limed peatland, were sampled around the Sudbury, Ontario, region, and were subjected to simulated drought. The simulated drought lowered soil water pH and dissolved organic carbon (DOC) concentrations, which is consistent with field observations. Metal partitioning (K d) values for Co, Mn, Ni, and Zn, with just one exception at one peatland, could be significantly predicted by just the pH of the soil water, although the strength of the relationship varied considerably among sites. The metal speciation model WHAM VII predicted that the free metal ion concentration of all metals tested, including Cu and Al, increased significantly with decreasing pH. At the same time, DOC-bound metal concentrations were predicted to decrease as DOC levels were lower, which for metals with strong organic matter affinities (Cu and Al) offset the increase in free metal ion concentration in soil solution following summer drought. Climate change forecasts for more frequent and sustained droughts may promote metal release from peatlands and increased mobilization to surface waters, and importantly, for some metals, the potential toxicity of the metals released from peatlands may increase to a greater extent than expected from increases in total metal concentrations because of decreased DOC following drought.

The effluent of the ornamental rock industry is characterized by presenting great concentrations of total solids, high contents of iron, and elevated pH, all responsible for the contamination of the superficial and ground waters, destruction of the soil, the vegetation, and the silting of the rivers. The purpose of this study is to assess the cytotoxic and genotoxic effects and the anatomical changes caused by the effluents arising from the ornamental rock polishing industry in root apex cells of Allium cepa L. (Amaryllidaceae). The samples of the effluent were collected in a polishing industry located in Nova Venécia, State of Espírito Santo, and were analyzed by mass spectrometry and atomic emission. Bulbs of A. cepa were exposed to the effluent at 12.5, 25, 37.5, 50, 75, and 100 % concentrations (residue in raw form) (v/v) for a period of 20 days. For the positive control, metilmethanesulfonate (MMS) at 4 × 10⁻⁴-M concentration was used, and distilled water was used for the negative control. The experiment was assessed taking into consideration the following parameters: mitotic index, frequency of chromosomal and nuclear abnormalities in the root apical meristem, and root anatomy. The mitotic index suffered a decrease proportional to the increase in the concentration of effluent. All the concentrations of the effluent led to chromosomal and nuclear abnormalities being stickiness and nuclear shoots the most frequent. The root apex evidenced changes that reflected on the decrease of the percentage area of the protoderm and the fundamental meristem and the increase in the areas of the cap and quiescent center. The symptoms of toxicity are related to the high frequency of cell in cellular death process observed in the roots exposed to the higher concentrations and to the decrease in the mitotic index of the apical root meristem.

Rhizoctonia zeae SOL3 fungus was isolated from contaminated soil based on its ability to decolorize remazol brilliant blue R in solid medium. This fungus has been used to degrade pyrene a four-ring polycyclic aromatic hydrocarbon. R. zeae SOL3 could biodegrade pyrene as a sole source of carbon and energy. Different parameters were investigated to study their effect on the biodegradation rate. The highest biodegradation rate reached at 28 °C, non-agitated culture, 20 g/L glucose, 24 g/L NaCl, and 20 mg/L pyrene. The metabolites of pyrene were detected by thin layer chromatography (TLC) and confirmed by gas chromatography–mass spectrometry (GC-MS), which were identified as benzoic acid, 4-hydroxybenzoic acid and botanic acid.

In the present study, facile and competent homogeneous liquid–liquid microextraction via flotation assistance (HLLME-FA) method combined with flow injection flame atomic absorption spectrometry (FI-FAAS) was proposed for simultaneous separation/preconcentration and determination of trace amounts of cadmium and copper in water samples. The efficient 2-(3,4-dihydroxyphenyl)-1,3-dithiolane (DHPDTO) with thiol groups was used as chelating reagent. The predominant parameters influencing the HLLME-FA, such as solution pH, concentration of DHPDTO, extraction and homogeneous solvent types and volumes, ionic strength, and extraction time were studied. Applying all the optimum conditions in the process, the detection limits of 0.008 and 0.01 μg L⁻¹, linear ranges of 0.08–40 and 0.1–45 μg L⁻¹, and the precision (RSD%, n = 7) of 3.4 and 3.9 % were obtained, respectively, for cadmium and copper. The proposed procedure showed satisfactory results for analysis of tap water, river water, well water, and seawater.

Marine tar residues originate from natural and anthropogenic oil releases into the ocean environment and are formed after liquid petroleum is transformed by weathering, sedimentation, and other processes. Tar balls, tar mats, and tar patties are common examples of marine tar residues and can range in size from millimeters in diameter (tar balls) to several meters in length and width (tar mats). These residues can remain in the ocean environment indefinitely, decomposing or becoming buried in the sea floor. However, in many cases, they are transported ashore via currents and waves where they pose a concern to coastal recreation activities, the seafood industry and may have negative effects on wildlife. This review summarizes the current state of knowledge on marine tar residue formation, transport, degradation, and distribution. Methods of detection and removal of marine tar residues and their possible ecological effects are discussed, in addition to topics of marine tar research that warrant further investigation. Emphasis is placed on benthic tar residues, with a focus on the remnants of the Deepwater Horizon oil spill in particular, which are still affecting the northern Gulf of Mexico shores years after the leaking submarine well was capped.

Silicate clay materials are promising natural adsorbents with abundant, low cost, stable, and eco-friendly advantages, but the limited adsorption capacity restricts their applications in many fields. Herein, palygorskite (PAL) was facilely activated with alkali to enhance its adsorptive removal capability for methylene blue (MB). The effects of alkali activation on the microstructure, physicochemical, and adsorption properties of PAL for MB were intensively investigated. It was found that the moderate alkali activation can partially remove the metal cations (i.e., Al³⁺, Mg²⁺) and Si in the crystal backbone of PAL by which new “adsorption sites” were created and the surface negative charges increased. The adsorption capacity and rate of PAL for MB were evidently enhanced due to the effective activation. The adsorption isotherms were described by Freundlich isotherm model very well, and the adsorption kinetics can be accurately presented by a pseudo-second-order model. It can be inferred from the fitting results that the overall adsorption process was controlled by external mass transfer and intra-particle diffusion (the dominant role). The multiple adsorption interactions (hydrogen bonding, electrostatic interactions, mesopore filling, and complexing) were turned out to be the dominant factors to improve the adsorption properties. It was revealed that the activated PAL could be used as a potential adsorption candidate for environmental applications.

Sixty years of air pollution from two Cu-Ni smelting plants (“Pechenganikel” and “Severonikel”) in the Kola region in northwest Russia have posed a severe threat for water quality, specifically acidification, in subarctic lakes. In the last two decades, emissions of SO2, Cu and Ni from the smelters have declined with 33 %, 40 % and 36 %, respectively. The 75 lakes in Kola Peninsula were sampled with 5-year intervals for the period 1990 to 2010. In addition, were analysed for major anions and cations, DOC and heavy metals. The lakes were grouped according to geology and distance to emission sources into 6 subregions. The most acid-sensitive lakes are located on granites, quartz sands or in highlands. Since 1990, ANС has increased, which is connected to the reduction of the contents strong acids in water (sulphate, chloride) while base cations concentrations have been almost unchanged. Despite the reduction of sulphate, concentrations of alkalinity have not increased in lake water. We have found an increase in concentration of dissolved organic carbon (DOC) and nutrients in Kola lake waters over a 20-year period. We suggest this phenomenon can be explained by two mechanisms: a reduction in deposition of strong acids and warming climate. Concentrations of Ni and Cu have decreased 5-10-fold over the last 20 years. We conclude that reduced emissions from Cu-Ni smelting plants has led to improved water quality in the Kola region.

Fluoroquinolone antibacterial agents (FQs) are the most commonly detected antibiotics in soil/groundwater which cause chronic effects on human beings as well as aquatic ecosystems. The current situation of the regulation, occurrence, fate, and sources of FQs in soil/groundwater was systematically analyzed in this paper. And then, the important factors affecting milligram per liter concentration of FQs sorption in soil, such as pH, cation exchange, clay minerals, organic content, surface complexation, and microbial degradation or transformation, were summarized. Actually, nanogram-microgram per liter concentration is detected frequently in soil/groundwater by far. Due to the extensive application of FQs and its relatively stable physicochemical characteristics, the higher concentration in soil/groundwater would appear in the coming decades which may exert a threat to freshwater and human beings. To the knowledge of the authors, no full-scale fate, occurrence, spatial, and temporal variations of FQs in soil/groundwater have been reported in the scientific literature. Therefore, it is recommended that more comprehensive studies are required to fill knowledge gaps in low-concentration transport, fate and occurrence, spatial, and temporal variations of FQs in soil/groundwater and their potential risk assessment to human and ecosystem.

The effects of ultrasonic wave irradiation on bacterial inactivation were investigated as functions of the ionic strength (IS), humic acid, and temperature. Escherichia coli (E. coli) D21g was selected as a model bacterium to better catch the effect of three parameters on the cell inactivation behavior. The Suwannee River humic acid (SRHA) was chosen as a representative humic acid, and the concentration for ultrasonic tests was kept to 10 ppm. The frequency of ultrasonic wave employed was 20 kHz, and the inactivation efficiency at two exposure times (5 and 10 min) was compared. The removal efficiency of E. coli D21g was confirmed to be 100 % at 10 min in all conditions except the 10-min temperature-controlled condition. The removal efficiency with the high IS was greater than that with the low IS, by 26 %, confirming an increase in the bacterial inactivation level with increasing IS. The bacterial removal efficiency with SRHA (96.6 %) was much greater than that without SRHA (69.6 %). The removal efficiency in the temperature-controlled condition (at a relatively low temperature) was significantly lower than that in the uncontrolled condition. Furthermore, the trend obtained using two other types of bacteria with more complex surface structure was consistent with that using the E. coli D21g cells.

Lignin is the major polluting and colouring constituent present in pulp and paper mill effluent. To degrade lignin and its derivatives, bacterial enzymes can play an important role due to stability at extreme environmental conditions. This study explored the degradation of pulp and paper mill effluent by a rod-shaped Gram-positive bacterial strain RJH-1, isolated from sludge, based on its efficiency to reduce COD, colour, AOX and lignin content. This bacterial isolate was able to grow in nitrogen-free Jensen medium. Further, RJH-1 was identified as Brevibacillus agri strain after 16 s rRNA gene sequencing. Degradation potential of this isolated bacterial strain was evaluated by batch and semi-continuous reactor study. In batch study, the isolate reduced 69 % COD, 47 % colour, 37 % lignin and 39 % AOX after 5 days whereas in control flask, 40 % COD, 26 % colour, 19 % lignin and 22 % AOX reduction was observed by the indigenous bacteria present in wastewater. During semi-continuous reactor study, it reduced 62 % COD, 37 % colour, 30 % lignin and 40 % AOX of effluent at a retention time of only 32 h whereas the reduction in control reactor was 36 % COD, 21 % colour, 18 % lignin and 29 % AOX. This study confirmed that the B. agri has the potential to degrade the lignin and reduce the colour and COD of the pulp and paper mill waste water.